Patent Publication Number: US-2022233335-A1

Title: Methods and tools for hip replacement with supercapsular percutaneously assisted total hip approach

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to the following applications, which are incorporated by reference herein in their entireties: the present application is a continuation of U.S. patent application Ser. No. 17/143,591, filed on Jan. 7, 2021, which is pending; U.S. patent application Ser. No. 17/143,591 is a continuation of U.S. patent application Ser. No. 16/686,512, filed Nov. 18, 2019, which is pending; U.S. patent application Ser. No. 16/686,512 is a continuation of U.S. patent application Ser. No. 14/910,632, filed on Feb. 5, 2016, which issued as U.S. Pat. No. 10,478,317 on Nov. 19, 2019; U.S. patent application Ser. No. 14/910,632 is the national stage entry of PCT/IB2014/002418, filed Aug. 6, 2014, which is expired; PCT/IB2014/002418 claims the benefit of U.S. Provisional Pat. App. No. 61/862,865, filed Aug. 6, 2013, which is expired. 
    
    
     FIELD OF DISCLOSURE 
     The disclosed devices, systems, methods and tools relate to surgical techniques. More particularly, the disclosed devices, systems, methods and tools relate to providing a replacement for a patient&#39;s hip with a minimal loss of blood, minimal tissue trauma, and a minimal length of operating time and patient recovery time. 
     BACKGROUND 
     Great progress has been made in the field of total hip arthroplasty (THA), commonly known as hip replacement. Hip replacements, particularly among the elderly, are now common. In spite of the considerable progress which has been made, many hip replacement operations still use relatively crude procedures. For example, it is common to make an incision of a relatively great length in a patient&#39;s hip as one of the first steps in a hip replacement operation. The incision may be as long as approximately eight inches (8″) to approximately twelve inches (12″). Large incisions may increase operating time and cause patients to lose large amounts of blood, suffer significant trauma to surrounding tissues, and require longer recovery periods. 
     Examples of minimally invasive hip procedures are disclosed in U.S. Pat. No. 6,997,928, issued to Penenberg and titled “Apparatus for and Method of Providing a Hip Replacement,” U.S. Pat. No. 7,105,028, issued to Murphy and titled “Tissue Preserving and Minimally Invasive Hip Replacement Surgical Procedure,” U.S. Pat. No. 7,651,501, issued to Penenberg et al. and titled “Instrument for Use in Minimally Invasive Hip Surgery,” and U.S. Pat. No. 7,833,229, issued to Penenberg and titled “Apparatus for and Method of Providing a Hip Replacement,” each of which is incorporated by reference herein in its entirety. These patents also disclose numerous tools for use in performing the minimally invasive hip procedures. The devices, systems, and methods disclosed herein improve on the tools and methods disclosed in these patents. 
     SUMMARY OF THE INVENTION 
     The present disclosure provides a minimally invasive and tissue preserving surgical procedure for replacing a patient&#39;s hip joint with an artificial hip prosthesis, with a minimal loss of blood, minimal tissue trauma, and a minimal length of operating time and patient recovery time. The present disclosure also provides the related tools, devices, systems, and methods. These include but are not limited to the following examples. 
     In one aspect, an exemplary surgical procedure for replacing a hip joint is provided. In the surgical procedure, a patient is first placed in a lateral decubitus position on a peg board having at least two pegs. In some embodiments, at least two anterior pegs are placed against a pubic symphysis of the patient, to act as a femoral fulcrum to lever a proximal femur. A main incision is made on an operative leg. The main incision is initiated at a point being a projection of a tip of a greater trochanter and extends proximally about a distance in the range of from 1 cm to 8 cm (for example, in the range from 6 cm to 8 cm) in line with the femoral axis of the operative leg. An inline capsulotomy is made to expose the hip joint capsule for accessing the hip joint. The inline capsulotomy is performed while keeping muscles and posterior capsule intact. The surgical procedure further comprises preparing the femoral canal of the femur in the operative leg for receipt of a femoral implant, resecting and removing the femoral head of the femur, and performing a step of acetabular preparation using a retractor comprising two tip rails, each tip rail having a plurality of tines. 
     In some embodiments, the step of preparing the femoral canal comprises reaming the femur to enter the femoral canal and expand proximal opening therein, and broaching the femur by placing a femoral broach in the femoral canal for use as a template. The step of preparing the femoral canal may further comprise cutting and removing bone fragments using a round box cutter osteotome configured to cut a bone and remove bone fragments simultaneously while spinning in one direction. 
     In some embodiments, the step of resecting and removing the femoral head comprises inserting a first Schanz pin into a solid part of the femoral head, and moving the first Schanz pin to rotate the femoral head. The step of resecting and removing the femoral head may further comprise inserting a second Schanz pin into a different solid part of the femoral head, and moving the second Schanz pin to rotate the femoral head. The first Schanz pin or the second Schanz pin may comprise a tip having cross threads. In some embodiments, the first Schanz pin and the second Schanz pin point to different directions. The femoral head is rotated to tear the ligamentum  teres  or expose the ligamentum  teres  outside the acetabulum. 
     In some embodiments, a mobile window for showing the acetabulum of the femur is formed by sliding the retractor having the two tip rails along soft tissues. In some embodiments, the step of performing a step of acetabular preparation using a retractor having two tip rails with tines comprises placing a bone hook into a broach inside and along the femur. The bone hook and the two tip rails are configured to form a three-point capsular distraction. The surgical procedure may further comprise holding an acetabular cup and moving the acetabulum cup into the acetabulum of the femur. 
     In some embodiments, the surgical procedure further comprises a step of dissection or retraction of tissues of different tissue planes. The step of dissection or retraction comprises the steps of placing a sharp dissector between a first two tissue planes, and placing a retractor along inner space of the sharp dissector between the first two tissue planes. The step of dissection or retraction further comprises removing the sharp dissector, placing the sharp dissector between a second two tissue planes, removing the retractor between the first two tissue planes, and placing the retractor along inner space of the sharp dissector. 
     In some embodiments, the surgical procedure further comprises the following steps: reaming the acetabulum by placing and rotating a reamer basket in the main incision using a reamer basket holder, placing and aligning an acetabular cup into the acetabulum, trying a trial neck and a trial head, disassembling the trial neck and the trial head, and assembling implants for the hip joint. A screw can be also placed into the acetabular cup through a pilot hole, which is drilled to a predetermined depth with the aid of a depth gauge. 
     In some embodiments, in the step of disassembling the trial neck and the trial head, the tip end of a bone hook tool is placed into a hole of a trial part. The trial part is connected to the trial neck. The bone hook tool comprises a bent tip with an indented surface as described herein. A tip of a blunt trocar having a round surface is placed into a hole on the trial neck. The round surface of the blunt trocar is engaged with the indented surface of the bent tip of the bone hook tool. The blunt trocar is rotated against the indented surface of the bone hook tool to move the tip of the blunt trocar away from the tip end of the bone hook tool. 
     In another aspect, the present disclosure provides different tools suitable for the surgical procedure. For example, in some embodiments, the present disclosure provides a retractor for acetabular preparation in a surgical procedure of replacing a hip joint. Such a retractor comprises two tip rails. Each tip rail comprises a plurality of tines substantially parallel to each other and to the respective tip rail. In one embodiment, the plurality of tines are symmetrically distributed on both sides along each tip rail. In another embodiment, each tip rail is straight to the end and has only the plurality of tines on one side of the respective tip rail. The retractor further comprises two arms. Each respective arm is at an angle to each respective tip rail. The retractor is configured to be able to slide along soft tissues to show an acetabulum in surgical procedure of replacing a hip joint, and an acetabular cup can be held and moved to the acetabulum. A method of using such a retractor is also provided in this disclosure. 
     In some embodiments, the present disclosure provides a bone hook tool. The bone hook tool comprises a bent tip with an indented surface on an outer side of the bent tip. The indented surface is configured to accept a convex surface of a second tool (e.g., a blunt trocar) to remove or disassemble a part to be removed (e.g., a trial neck) from a trial part or an implant without any dislocation. The indented surface is configured to accept a round surface of the second tool. The indented surface may be smooth or textured. The bone hook is configured to be engaged with the second tool with a tip end of the bent tip inserted into a hole on the trial part or the implant and a tip of the second tool inserted into a hole on the part to be removed. The second tool is rotated against the indented surface of the bone hook tool. The part to be removed is disassembled when the tip of the second tool are moved away from the tip end of the bone hook tool. A method of using such a bone hook tool is also provided in this disclosure. 
     In some embodiments, the present disclosure provides a depth gauge for centering a screw in a surgical procedure. The depth gauge comprises a body, and a first end and a second end. The body may be straight and cylindrical. The first end comprises a screw head or is adapted to be coupled with a screw head. The second end comprises depth marks. In some embodiments, the depth gauge has an outer diameter and is configured to pass through a cannula having an inner diameter larger than the outer diameter of the depth gauge. The depth gauge has an inner diameter and is so configured that a pin (e.g., a Schanz pin) can pass through the depth gauge. The depth marks in the second end of the depth gauge are configured to indicate and control the depth of insertion of the pin. A method of using such a depth gauge is also provided in this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not necessarily to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Like reference numerals denote like features throughout specification and drawings. 
         FIG. 1  illustrates a “home position” of a patient lying on a peg board in accordance with some embodiments. 
         FIG. 2  illustrates an exemplary peg board in some embodiments. 
         FIG. 3  is an enlarged fragmentary sectional view illustrating patient positioning on the peg board of  FIG. 2  in some embodiments. 
         FIGS. 4-6  illustrate a method of making an incision of soft tissues on an operative leg in some embodiments. 
         FIGS. 7-12  illustrate an exemplary method of retraction using the placement and replacement techniques in some embodiments. 
         FIGS. 13-14  illustrate a step of capsular exposure in some embodiments. 
         FIGS. 15-16  illustrate an exemplary method of inline capsulotomy in some embodiments. 
         FIGS. 17-18  illustrate a step of capsular incision in some embodiments. 
         FIGS. 19-22  illustrate a method of femoral preparation in some embodiments. 
         FIGS. 23-24  illustrate a step of femoral broaching in some embodiments. 
         FIG. 25  illustrates a step of resecting femoral head in some embodiments. 
         FIGS. 26-28  illustrate exemplary tools and an exemplary method of measuring the femoral head before resecting the femoral head in accordance with some embodiments. 
         FIG. 29  illustrates an exemplary method of cutting and removing bone fragments during the step of preparation of femur in some embodiments. 
         FIG. 30  illustrates a step of femoral head removal in some embodiments. 
         FIGS. 31-35  are sectional views illustrating a method of removing the femoral head in accordance with some embodiments. 
         FIG. 36  illustrates a step of acetabular preparation in some embodiments. 
         FIGS. 37-39  illustrate a modified Zelpi retractor having tines in accordance with some embodiments. 
         FIGS. 40-42  illustrate exemplary methods of using the modified Zelpi retractor of  FIGS. 37-39  in some embodiments. 
         FIGS. 43-44  illustrate a step of percutaneous incision placement in some embodiments. 
         FIGS. 45-47  illustrate exemplary tools used in the step of  FIGS. 43-44  in some embodiments. 
         FIGS. 48-49  illustrate a step of acetabular reaming in some embodiments. 
         FIGS. 50-51  are sectional views illustrating a method and a tool for placing and removing a reamer basket in accordance with some embodiments. 
         FIGS. 52-53  illustrate a step of cup placement in some embodiments. 
         FIGS. 54-55  illustrate a depth gauge in accordance with some embodiments. 
         FIGS. 56-57  illustrate a method of using the depth gauge of  FIG. 57  in some embodiments. 
         FIG. 58  illustrates an alternative tool or method of having depth marks on a pin or drill in some embodiments. 
         FIG. 59  illustrates a step of trial reduction in some embodiments. 
         FIG. 60  illustrates a step of trial disassembly in some embodiments. 
         FIGS. 61-63  illustrate a bone hook tool having an indented surface in accordance with some embodiments. 
         FIGS. 64-68  illustrate exemplary method of using the bone hook tool of  FIGS. 61-63  in some embodiments. 
         FIGS. 69-70  illustrate a step of assembling implants in some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     This description of the exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. In the description, relative terms such as “lower,” “upper,” “horizontal,” “vertical,”, “above,” “below,” “up,” “down,” “top” and “bottom” as well as derivative thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. 
     The posterior approach is considered the gold standard of total hip arthroplasty (THA), commonly known as a hip replacement, allowing access to the hip joint for the placement of components without any femoral head size limitation. Specifically, the posterior approach allows for the use of big femoral head prostheses and ream-and-broach or broach-only femoral stems. 
     This invention provides devices, systems, methods and tools for hip replacements with supercapsular percutaneously assisted total hip (SUPERPATH™) approach, which is a modification of the standard posterior approach, with the added benefit of allowing for the short external rotators to remain intact. Preservation of these muscles can decrease operative time, post-operative recovery and intra-operative blood loss, and increase post-operative stability while requiring fewer post-operative movement restrictions. This approach maintains all of the advantages of the standard posterior approach and is also extensile, being easily converted to the standard posterior approach, making it easy to learn and providing the surgeon complete freedom during the operation. The resulting surgical technique provides a replacement for a patient&#39;s hip with a minimal loss of blood, minimal tissue trauma, a minimal length of operating time and patient recovery time. 
     The necessary size of a THA incision decreases as the angular constraints of the femoral component and acetabular reamers are addressed. Modularity in the design of the femoral component allows access to the femur in a manner similar to an intramedullary (IM) rod—that being directly superior. With the SUPERPATH™ approach, acetabular preparation can be performed through a percutaneous incision. 
     Accessing the femur through the trochanteric fossa with the femoral head intact absorbs some hoop stresses during reaming and allows for less chance of fracture associated with the insertion of noncemented femoral components. To prevent  varus  orientation of these components, a lateralizing trochanteric reamer is recommended. 
     Additionally, offset is easily determined after broaching the femur with the head in situ. When the appropriate size broach is seated, the neck osteotomy permits precise resection of the neck—representing the exact offset without major acetabular deformity. 
     Acetabular preparation is performed through a small portal incision, allowing medialization with the reamers. Direct visualization allows precise placement of the acetabular component. Working through a cannula, the leg can be moved to easily access all boundaries of the acetabulum, regardless of patient anatomy. In addition, acetabular preparation will not be obstructed by the greater trochanter or the proximal femur. And using an alignment handle and a blunt trocar, the risk of damaging the sciatic nerve is minimized, with a safe zone posterior to the femur of at least 2.5 cm. 
     The tools, devices, instruments, systems, implants, methods and surgical procedures provided in this disclosure are for use in total hip arthroplasty for reduction or relief of pain and/or improved hip function in skeletally mature patients. The indications for use include but are not limited to non-inflammatory degenerative joint disease such as osteoarthritis, avascular necrosis, ankylosis, protrusio  acetabuli , and painful hip dysplasia; inflammatory degenerative joint disease such as rheumatoid arthritis; correction of functional deformity; and revision procedures where other treatments or devices have failed. 
     The devices, systems, methods and tools provided in this disclosure are described based on a general sequence of the surgery. In the drawings, like items are indicated by like reference numerals, and for brevity, descriptions of the structure, provided above with reference to the previous figures, are not repeated. The methods or surgical techniques are described with reference to the exemplary structure described in the corresponding drawings. A surgical technique guide, titled “SUPERPATH™ Micro-Posterior Approach, SURGICAL TECHNIQUE,” published by Wright Medical Technology, Inc. (a part of which becomes MicroPort Scientific Corporation) in 2012 (No. MH382-512, hereinafter “Surgical Technique Guide”), is incorporated by references herein in its entirety. Some tools are described with reference to respective part or product numbers (P/N) described in the SURGICAL TECHNIQUE or other product brochures. All the tools and devices described in the present disclosure can be made of a suitable material, including but not limited to metal, plastics or any combinations thereof. 
     Accurate preoperative templating requires good quality standardized radiographs of the pelvis and operative hip. Preoperative templating may be used for estimation purposes. Final component size and position can be accurately determined intraoperatively. For example, X-ray templates may be used to estimate the size of the product to be used. The anatomy of the patient ultimately determines the size of the product for an individual patient. 
     (1) Patient Positioning 
     As shown in  FIG. 1 , a patient is placed in a lateral decubitus position in a location comfortable for the operating surgeon. A peg board  2  with pegs  4  is used for patient positioning. Pegs  4  may be radiolucent. The operative leg  6  for the surgery faces up as shown in  FIG. 1 . In some embodiments, due to the nature of this technique, it may not be needed to bias the location of the patient to the anterior edge of the operating table as maximal leg adduction is not needed. 
     In some embodiments, a peg board  2  comprises at least two pegs  4  configured to match the locations of the patient&#39;s body: two long pegs at the pubic symphysis, two long pegs at the sacrum, a long peg at the chest level and just below the breast, a long peg at the shoulder blades. 
     To ensure appropriate pelvic rotation, bias the hip to lean slightly posterior. Flex the operative hip 45° and internally rotate the operative leg 10°-15° to present the greater trochanter upward. With the operative foot resting on a padded mayo stand and the leg in slight adduction, the weight of the leg  6  will balance the hip, bringing the pelvis to neutral rotation. This is the “home position” of the technique as the operative leg  6  will remain there for most of the procedure. 
     Referring to  FIG. 2 , an exemplary peg board  2  is used for positioning a patient in some embodiments. Pegs  4 - 1  and  4 - 2  as anterior pegs are placed against pubic symphysis of the patient, and act as a femoral fulcrum to lever the proximal femur  10  out of the socket. Pegs  4 - 1  and  4 - 2  also prevents anterior “rolling” of pelvis  8 . Referring to  FIG. 3 , an enlarged view illustrates the patient positioning on the peg board  2  of  FIG. 2 . In this method of positioning the patient, a downward pressure exists on the knee and the operative leg  6 . The hip is “lifted” out the socket without any twisting. This positioning method does not require additional soft-tissue dissection due to mechanical advantage. 
     (2) Soft Tissue Dissection 
     Referring to  FIGS. 4-6 , in an exemplary method of making a main incision  12  of soft tissues on an operative leg  6  for subsequent accessing a hip joint in some embodiments, the main incision  12  is initiated at a point which is a projection of a tip of a greater trochanter and extends proximally about a suitable distance of 8 cm or less, for example, in the range from 1 cm to 8 cm. In some embodiments, the incision  12  is extended about 6-8 cm proximal, in line with the femoral axis (as shown in  FIG. 4 ). The incision  12  is made to the level of the gluteus maximus investing fascia  11 . The fascia  11  is then incised using electrocautery, starting at the tip of the greater trochanter and extending in line with the main incision  12 . 
     The operative leg  6  can be flexed, extended or adducted to adjust visualization through the main incision  12 . In some embodiments, two wing-tipped elevators (e.g., P/N 20070038; angled versions may also be used, e.g., P/N 20070040) are used to split the gluteus maximus, exposing the bursa overlaying the gluteus  medius . A very thin layer of bursa tissue is carefully incised along the posterior border of the gluteus  medius.    
     A Cobb elevator is placed under the gluteus  medius , then replaced with a blunt Hohmann retractor  14  (e.g., P/N 20073114). An assistant can use gentle pressure to maintain position of the retractors  14  and  16  while protecting the gluteus  medius . In some embodiments, the blade of the blunt Hohmann retractor  14  are not be forced beyond 90° from the wound and now is resting in the interval between the gluteus  medius  and gluteus minimus. Sometimes the release of short, external rotators may be necessary, especially in tight hips. 
     After dissecting soft tissue, the incision  12  is shown in  FIGS. 5 and 6 .  FIG. 6  is an enlarged view of the incision  12  and resulting hip socket. Different muscles without any damages can be seen. For example, these muscles may include superior  gemellus  muscle  18 ,  piriformis  muscle  20 , obturator  intermus  muscle  22 , and gluteus minimus muscle  24 . 
     Referring to  FIGS. 7-12 , an exemplary method for dissection or retraction (or both) is used in the step of soft tissue dissection (or the subsequent step of capsular exposure and any other suitable step in the surgical procedures) in some embodiments. This method can be also used for dissection or retraction (or both) of any tissue involving different tissue planes, either horizontally or vertically. This exemplary method, using techniques of placement and replacement, comprises the steps described as follows with references to  FIGS. 7-12 . 
     Referring to  FIG. 7 , a sharp dissector (or retractor) such as a Cobb elevator  28  is placed toward and inserted into a tissue  26  having three tissue planes  26 - 1 ,  26 - 2  and  26 - 3 . Three tissue planes  26 - 1 ,  26 - 2  and  26 - 3  can be oriented in any direction, including but not limited to either horizontally or vertically.  FIG. 7  and any other drawings in  FIGS. 8-12  can be interpreted as a top down view, a sectional view or a view from any other direction. Even though parallel tissue planes are shown in  FIGS. 7-12 , the tissue planes are not necessarily parallel in some other embodiments. 
       FIG. 8  illustrates that a sharp dissector such as a Cobb elevator  28  is placed in between a first two tissue planes, for example, between tissue planes  26 - 1  and  26 - 2 . The step of placing the Cobb elevator  28  can be performed while dissecting soft tissues. 
     Referring to  FIG. 9 , a retractor such as a blunt Hohmann retractor  30  is placed along inner space of the Cobb elevator  28  after the Cobb elevator  28  is placed in between two tissue planes ( 26 - 1  and  26 - 2 ). 
     Referring to  FIG. 10 , the sharp dissector such as the Cobb elevator  28  is removed. The retractor  30  is positioned between tissue planes  26 - 1  and  26 - 2  for retracting, and also provides temporary visibility for further dissection. 
     Referring to  FIG. 11 , the sharp dissector such as the Cobb elevator  28  is placed into (or used to dissect) a new interval or between two different tissue planes such as a second two tissue planes  26 - 2  and  26 - 3 . 
     Referring to  FIG. 12 , the retractor such as the blunt Hohmann retractor  30  is removed from the space between tissue planes  26 - 1  and  26 - 2 , and placed along inner space of the Cobb elevator  28  at the new interval, for example, between tissue planes  26 - 2  and  26 - 3 . 
     The Cobb elevator  28  is then removed, and these steps are repeated if needed. 
     This exemplary method of  FIGS. 7-12  with reduced invasiveness is referred as a “swimming” method of dissection and retraction. This method offers several advantages. For example, dissection is made only for what is required for retractor placement. Specialized dissectors and retractors that are matched in size are used. Additional dissection is avoided. This method may be used in existing potential spaces between structures, or in newly created spaces. 
     (3) Capsular Exposure 
     With an assistant abducting and externally rotating the hip (raise the knee while keeping the foot on the Mayo stand) to decrease tension in the external rotators, a surgeon can place a Cobb elevator  28  posteriorly between the  piriformis  tendon  20  and the gluteus minimus  24 . The sciatic nerve will be protected by the external rotators. The Cobb elevator  28  is then replaced with a blunt Hohmann retractor  14 , with the blunt Hohmann  14  now resting between the posterior capsule (hip joint capsule)  32  and the external rotators. The blade of the blunt Hohmann retractor  14  should not be forced beyond 90°, and the handles of the Hohmann retractors  14  should be parallel to one another. The knee is then lowered, and the leg returned to the “home position.” If excessive force is generated by the  piriformis  tendon  20 , it can be released at this time under direct visualization. After the step of capsular exposure, the exposed capsule  32  is illustrated in  FIGS. 13-14 . 
     As intra-operative views,  FIGS. 15-16  illustrate an exemplary method of inline capsulotomy  36  to expose the hip joint capsule  32  for accessing the hip joint in some embodiments. “A” and “P” in  FIGS. 15-16  represent “anterior” and “posterior,” respectively.  FIG. 15  is a sectional view of the incision site in preparation for the capsulotomy  36 . Femoral head  34 , femoral neck, and the greater trochanter  38  are shown in or around the capsule  32  relative to the locations of pelvis  8  and femur  10 .  FIG. 16  is a top-down view illustrating the inline capsulotomy  36 . Retractor  16  is shown relative to the locations of  piriformis  muscle  20 ,  medius  muscle  21  and minimus muscle  23 . 
     Inline capsulotomy  36  allows for keeping  piriformis  muscle  20  and posterior capsule intact for in-situ total hip arthroplasty (THA). Inline capsulotomy  36  facilitates all soft-tissue retraction due to the effect of “reverse tent.” The hip is placed in flexion, slight adduction and slight internal rotation. Inline capsulotomy  36  maintains tension from retractors  16 . The access to the hip joint will allow for a superior (vertical) capsulotomy to be performed on the hip joint. Inline capsulotomy  36  facilitates anatomic closure, “rotator—cuff repair,” and water-tight closure. 
     (4) Capsular Incision 
     Referring to  FIGS. 17-18 , a step of capsular incision is performed.  FIG. 18  is an enlarged view of the incision area of  FIG. 17 . 
     Use a Cobb elevator  28  to gently push the posterior border of the gluteus minimus  24  anteriorly to expose the underlying capsule  32 . The capsule  32  is then incised in-line with the main incision  12  using electrocautery  40 . In some embodiments, electrocautery  40  with a long tip is used to incise the trochanteric fossa to prevent bleeding of the anastomosis around the base of the femoral neck. Complete preparation of the entire saddle portion of the femoral neck and greater trochanter is ensured using electrocautery  40 . Over-preparation is better than under-preparation in regards to reducing bleeding amongst the many recurrent vessels in this area. The capsulotomy is extended from the saddle of the femoral neck to 1 cm proximally on the acetabulum. 
     The 1 cm capsular attachment subperiosteally can be carefully peeled off of the acetabular rim, extending 1 cm anteriorly and posteriorly. This part of the dissection can be limited to only 1 cm in all directions. An assistant can notify the surgeon of any foot movement as the sciatic nerve lies 2 cm posteriorly. The capsular incision should be a simple, straight line and will be repaired like a rotator cuff in the end. 
     With an assistant lifting the knee to decrease external rotator tension, a Cobb elevator  28  is placed intra-articularly between the posterior capsule and the posterior femoral neck. The Cobb elevator  28  is then replaced with the blunt Hohmann retractor  14  that was previously located at the posterior capsule, and the leg is returned to the “home position.” The anterior blunt Hohmann retractor  14  is re-positioned intra-articularly in a similar fashion. The capsule is tagged for identification during repair, and the  piriformis  fossa, the tip of greater trochanter and the anterior femoral neck (Saddle) are isolated. 
     (5) Femoral Preparation 
     Referring to  FIGS. 19-22 , a step of femoral preparation is performed in some embodiments. The femur  10  is reamed and broached with the head intact to minimize the risk of a femoral neck fracture. The step of femoral preparation includes reaming the femur to enter the femoral canal and expand proximal opening therein. With an assistant applying gentle adduction pressure to the knee of the patient, the saddle of the femoral neck is presented into the incision. 
     As shown from  FIG. 19  to  FIG. 20 , a reamer  42  such as a starter reamer (for example, with a product number P/N PRR00080 or 4700R09000) is used to enter the femoral canal through the trochanteric fossa. Another reamer  42  such as a metaphyseal reamer (e.g., P/N PTMR0001) can be used to expand the proximal opening, ensuring that subsequent instruments are properly aligned and not positioned in  varus.    
     Referring to  FIG. 21 , to allow for easier insertion of the femoral broaches subsequently, an appropriately sized round calcar punch  44  (e.g., P/Ns 20070052, 20070053 and 20070054) and impactor handle (e.g., P/N 8000010) are utilized in some embodiments. In some embodiments, a round box cutter osteotome  60  can be also used as described in  FIG. 29 . By opening the neck and starting at the reamer opening, a slot can be created toward the acetabular rim. Additional adduction pressure can be applied to maximize the exposure. 
     Referring to  FIG. 22 , a calcar curette  46  (e.g., P/N 20071006) is then introduced into the femur  10  to prepare the proximal-medial portion of the canal, making sure the surface provides good cortical contact to promote bone on-growth while preventing subsidence and micromotion. 
     Referring back to  FIG. 21  and forward to  FIG. 29 , an exemplary method of cutting and removing bone fragments can be used during the step of femur preparation in some embodiments. The round box cutter osteotome  60  can be a round calcar punch  44 , or a modified variation, and has a lower end of cylindrical shape with an opening on the wall parallel to the central axis. As illustrated in  FIG. 29 , the round box cutter osteotome  60 , which is coupled with a spinning tool (not shown), is configured to cut the bone when it spins in one direction, while removing the bone fragments simultaneously. The bone fragments are removed through the opening on the wall. In some embodiments, a “walking canoe” is prepared by forming a hole from the initial starting reamer hole  62  (on the right side as shown in  FIG. 29 ) at the end of femur  10  to the center of femoral head  34 . The round box cutter osteotome  60  is very efficient for rapid and precise preparation of femur in-situ with bone fragment removal. In addition, the round box cutter osteotome  60  can be repeatedly used during the surgery without the need of extensive cleaning. 
     (6) Femoral Broaching 
     Referring to  FIGS. 23-24 , a step of femoral broaching is performed in some embodiments.  FIG. 24  is an enlarged sectional view of a portion of  FIG. 23  illustrating the location of broaches  50  in the femur  10  having femoral head  34 . Femoral broaching, also a step of femoral preparation, is performed by placing a femoral broach in the femoral canal for use as a template. 
     To prepare the femoral canal, broaches  50  can be utilized according to the appropriate ream-and-broach or broach-only stem selected. A slotted broach handle  48  (e.g., P/N SLBROHAN) includes measurement markings to facilitate in the determination of the depth of the top of the broach with regards to the tip of the greater trochanter. The depth is typically 15-25 mm and varies depending on patient anatomy and preoperative leg length discrepancy and can also be checked using a canal feeler (e.g., P/N 20071008). Once the final broach  50  is seated, the broach handle  48  is removed and the broach  50  is used as an internal neck cutting guide. Broach  50  is removed subsequently before the hip replacement parts are implanted. 
     The methods and the tools related to broaching are also described in U.S. Pat. No. 7,105,028, which is incorporated herein by reference in its entirety. 
     (7) Femoral Head Resection 
     Referring to  FIG. 25 , a step of resecting femoral head  34  is performed in some embodiments. To bring the plane of the femoral neck osteotomy in-line with the surgical wound, an assistant can help to lift the knee in slight hip abduction. A saw  52  such as an oscillating saw with a narrow blade is used to create the femoral neck osteotomy along the top of the broach  50  (P/N PLSB0015, for example). The anterior and posterior sections of the cut are completed using another saw  52  such as a reciprocating saw. 
     Referring to  FIGS. 26-28 , exemplary tools and an exemplary method are used to measure the femoral head  34  before resecting the femoral head  34  in accordance with some embodiments. The exemplary method is a method of head-center offset measurement for in-situ total hip arthroplasty (THA).  FIG. 26  is a perspective view of a measuring tool  54  and a short modular neck  56  in a femoral head  34  having a broach  50 .  FIG. 27  is a sectional view of the measuring tool  54  inserted into the broach  50  or an implant  56  inside the femoral head  34 .  FIG. 28  is a top-down view of the set-up of  FIG. 27 . 
     In some embodiments, the measuring tool  54  is a “back hook” trial cup remover used to remove a trial cup in subsequent procedures. The measuring tool  54  can be also a modified “back hook” trial cup remover. The measuring tool  54  has a lower end near the tip. The length of the lower end x as shown in  FIG. 26  is configured to have about the same as the distance (x′) from the center of rotation in the femoral head and the top surface of an implant  56  such as a short profemur modular neck as shown in  FIG. 26 . The distance is the sum of the length of the implant  56  and additional femoral offset (y) of implant relative to native femur. The modular neck as an implant  56  can be inserted into the broach  50  in some embodiments. 
     As shown in  FIGS. 27-28 , the measuring tool  54  (e.g., a back hook trial cup removal or a modified variation) can be inserted into the broach  50  or an implant  56  inside the femoral head  34  to measure the center of rotation of the broach  50  or the implant  56 , and the additional femoral offset (y) of implant relative to native femur. In some embodiments, the measuring tool  54  can be modified to match with any implant or any sizing, including nonmodular stems. 
     (8) Femoral Head Removal 
     Referring to  FIG. 30 , a step of femoral head removal is performed in some embodiments. A first Schanz pin  66  (e.g., P/N 20070057) is inserted into a solid part of the femoral head  34 , and the first Schanz pin  66  is levered to rotate the femoral head  34  into maximum adduction. A Schanz pin  66  can be coupled with a handle  67 . A second Schanz pin  66  is then placed into another solid part of the femoral head  34  and, using the drill chucks still attached, the femoral head  34  is pulled from the main incision. Should the head be difficult to extract, the first Schanz pin  66  can be removed and the femoral head  34  rotated further into adduction before inserting another pin. The femoral head  34  can continually be “walked” into maximal adduction until the ligamentum  teres    70  is either torn or is presented so that it may be severed with electrocautery. 
     An exemplary method of removing the femoral head  34  is illustrated in details in  FIGS. 31-35  in accordance with some embodiments. This method is also referred as “Shantz pin walking” technique. Referring to  FIG. 31 , the femoral head  34  is located inside the acetabulum  68  and connected with the acetabulum  68  through ligamentum  teres    70 . The first Schanz pin  66  is inserted into a solid part of the femoral head  34 . The first Schanz pin  66  can be used to rotate the femoral head  34  into maximum adduction. 
     Referring to  FIG. 32 , a second Schanz pin  66  is then placed into another solid part (a different solid part) of the femoral head  34 . The ligamentum  teres    70  may be stretched at this stage. In some embodiments, the first Schanz pin  66  can be removed before inserting the second Schanz pin  66 . 
     Referring to  FIG. 33 , the second Schanz pin  66  can be used to rotate the femoral head  34  into maximum adduction. 
     Refereeing to  FIG. 34 , when the second Schanz pin  66  can be used to rotate the femoral head  34 , the ligamentum  teres    70  may be torn, exposed, or removed from the acetabulum  68 . The ligamentum  teres    70  outside the acetabulum  68  can be directly dissected in some embodiments. 
     Referring to  FIG. 35 , the first Schanz pin  66  can be inserted to another solid portion of the femoral head  34 . The two Schanz pins  66  can point to different directions. This cross-pin fixation can be used for extraction of the femoral head in situ total hip arthroplasty (THA). As shown in  FIG. 35 , in some embodiments, the pins  66  used have cross threads in the tips for better fixation and removal. 
     The pins  66  and the related techniques for the femoral head removal are for the illustration purpose only. The pins  66  and the related techniques described can be applied to any type of bones including bone fractures. The fixation/removal can be done with streamlining and less expensive tooling. 
     (9) Acetabular Preparation 
     Referring to  FIG. 36 , a step of acetabular preparation is performed in some embodiments. With the leg in the “home position,” two spiked Hohmann retractors (e.g., P/N 20073113, not shown) are placed into the axilla between the capsule and the labrum on both the front and back sides of the acetabulum  68 . Under direct visualization, any remaining tissue is removed from the acetabulum  68 , as well as the labrum, to expose the surface and volume  80  of the acetabulum  68 . The obturator artery is often encountered posteriorly. After removal of soft tissue, bleeding can be controlled using electrocautery (a long tip is recommended). 
     A Zelpi retractor  76  (e.g., P/N 20071004) or a modified variation is placed subperiosteally at the acetabular margin at the proximal incision, and a Romanelli retractor  78  (e.g., P/N 20071001) immediately distal intra-articularly. The combination of these self-retaining retractors  76  and  78  will provide rotational stability, as well as create a surface on which to introduce the reamers and the implant into the joint. The spiked Hohmann retractors are now removed. 
     Referring to  FIGS. 37-39 , the inventor has designed a series of new Zelpi retractor  76  having tines  81  in accordance with some embodiments.  FIG. 37  illustrates a Zelpi retractor  76  having two tip rails  77 . Referring to  FIG. 38 , in some embodiments, each tip rail  77 - 1  has a plurality of tines  81  symmetrically distributed on both sides along the tip rail  77 - 1 . Referring to  FIG. 39 , in some other embodiments, the tip rails  77 - 2  are straight to the end. Tip rail  77 - 2  has tines  81  only on one side of the tip rail  77 - 2 . In some embodiments, the tines  81  in either tip rail  77 - 1  or  77 - 2  are substantially parallel to each other and to the respective tip rail. The inventive Zelpi retractor  76  provided in the present disclosure can have tip rail type  77 - 1  or  77 - 2  with the tines  81  described, or any combinations thereof. The inventive Zelpi retractor  76  having tines can facilitate subsequent insertion of an acetabular cup, and also provide unencumbered access to the acetabulum  68 . 
     Referring to  FIGS. 40-42 , the modified Zelpi retractors  76  shown in  FIGS. 37-39  can be used to facilitate the surgery.  FIG. 40  is a top down view of a modified Zelpi retractor  76  being used. As shown in  FIG. 40 , the modified Zelpi retractor  76  having tines can be used to create an open space to show the acetabulum  68  with its surface/volume  80 . The modified Zelpi retractor  76  can be moved by sliding along soft tissues only to create a different open space (a mobile window) to facilitate subsequent insertion of an acetabular cup. Additionally, the modified Zelpi retractor  76  having tines has two arms. Each arm is at an angle (such as 90 degree) to a respective tip rail  77 - 1  or  77 - 2 . The modified Zelpi retractor  76  creates or functions as a “railway” to hold and move the acetabular cup or other parts such as a reamer basket, for example, into the acetabulum of the femur. 
       FIG. 41  is a side view and  FIG. 42  is a top down view of a modified Zelpi retractor  76  being used in combination with other tools such as a bone hook  82 , which is placed in the broach  50  inside and along the femur  10 . In all the traditional hip replacement techniques, bone retraction is used. As described, by retracting soft tissues only, the modified Zelpi retractor  76  in the present disclosure can be used to create a mobile window (over the existing capsule), including the surface/volume of the exposed acetabulum  68 . By moving retraction along or to the soft tissue, better exposed is achieved with less dissection by the method of creating a mobile window. The retractors are not fixed to stationary bony structures. The existing capsule can be used to further aid retraction. As shown in  FIG. 42 , with the aid of bone hook  82 , a three-point capsular distraction is achieved. The bone hook and the two tip rails are configured to form the three-point capsular distraction. The bone hook  82  placed in broach  50  allows distraction without force directly on any bone including the femur  10 . The three-point capsular distraction provides maximum protection to muscles, nerves, and vessels. Overall, by using the modified Zelpi retractor  76  having tines, a minimally invasive hip replacement is achieved. The incision is easily sealed and easily heals. 
     (10) Percutaneous Incision Placement 
     Referring to  FIGS. 43-44 , a step of percutaneous incision placement is performed in some embodiments. The exemplary tools shown in  FIGS. 45-48  are for the illustration purpose only. 
     With the leg still in the “home position,” have an assistant insert the tip of the bone hook  82  (e.g., P/N 20071011) into the top of the broach  50  and retract the femur  10  anteriorly. An assembly  92  comprising an alignment handle (e.g., P/N 20071009), a portal placement guide (e.g., P/N 20070015), a threaded cup adapter (e.g., P/N 20070013) and a trial cup  84  (e.g., P/N 20070146, shown in  FIG. 45 ), is seated in the acetabulum  68  with the top of the guide perpendicular to the patient&#39;s torso, and the guide shaft tilted 10°-15° from vertical to account for the pelvic tilt of the patient on the table. The methods and the tools related to using an assembly comprising an alignment handle are also described in U.S. Pat. No. 7,651,501, which is incorporated herein by reference in its entirety. 
     A blunt Trocar  90  (e.g., P/N 20070116,  FIG. 47 ) with a cannula  88  (e.g., P/N 2007ST20,  FIG. 46 ) is inserted until resting against the operative leg. At the point where the blunt Trocar  90  intersects the leg, a 1 cm stab incision (a portal incision) is made horizontally. The blunt Trocar  90  and the cannula  88  are then passed through the stab incision and 1-2 cm posterior to the femur  10  until they are visible through the main incision. The assembly  92  of alignment handle/portal placement guide/threaded cup adapter/trial cup and blunt Trocar  90  are then removed, leaving the cannula  88  in place. The cannula  88  can be easily moved for directional reaming by positioning the leg. 
     The methods and the tools related to using a cannula are also described in U.S. Pat. No. 6,997,928, which is incorporated herein by reference in its entirety. 
     (11) Acetabular Reaming 
     Referring to  FIGS. 48-49 , a step of acetabular reaming is performed in some embodiments.  FIG. 49  is an enlarged view of a portion of  FIG. 48 . An appropriately-sized reamer  94  such as a hex acetabular reamer (e.g., P/Ns PATHRM40-PATHRM64) is passed into the main incision using a reamer basket holder  96  (e.g., P/N 20070048). A reamer shaft  97  (e.g., P/N 20070011) is passed through the cannula  88  and mated to the reamer  94  such as the hex acetabular reamer in situ. Acetabular preparation is performed using the preferred reaming method. Medial reaming is often carried out through the main incision prior to deepening/enlarging the acetabulum  68 . 
     Referring to  FIGS. 50-51 , an exemplary method with an exemplary tool is used for placing and removing a reamer basket  94  in accordance with some embodiments. As shown in  FIG. 50 , a reamer basket  94  such as a hex acetabular reamer is placed into the acetabulum  68 . In some embodiments, this step is performed using a unique reamer basket holder  96  as shown in  FIG. 51 . The reamer basket holder  96  provided in the present disclosure comprises a substantially straight main body, a small bent bottom tip and a bigger bent top handle. The small bent bottom tip is at an angle with the main body, or is substantially perpendicular to the main body in some embodiments. The small bent bottom tip has a suitable size and is configured to be inserted into a hole on the reamer basket  94  as shown in  FIG. 51 . As shown in  FIG. 51 , the bent top handle can be bent twice. The top handle is configured to be easily grabbed by a hand. The reamer basket holder  96  is configured to rotate the reamer basket  94  around the contacting point after the tip of the reamer basket holder  96  is placed into the reamer basket  94  ( FIG. 51 ). 
     During the step of acetabular reaming, in some embodiments, the acetabulum  68  can be first reamed using different sized reamers. Second, at one size smaller than final implant size, the reamer basket  94  should display rotational resistance. The reamer basket  94  should remain in the position against its gravity. Third, final implant size is reamed using a limited number of revolutions, and the final implant has a minimal impact to sphericity of acetabular preparation. This method of acetabular reaming does not need to separately have trial cups. With streamlining tooling, it is not necessary to supply extra parts for the trialing steps. The method provides much reduced cost for manufacturing and inventory. The method also provides streamlined operational flow, with much easier procedure, higher surgeon adoption and easier set-up. 
     (12) Cup Placement 
     Referring to  FIGS. 52-53 , a step of cup placement is performed in some embodiments. A threaded cup adapter  98  is threaded into the apical hole of an acetabular cup  97 , and an acetabular cup  97  and threaded cup adapter  98  are seated on an assembly comprising an alignment handle  92 , as shown in  FIG. 52 . The alignment handle  92  is designed to provide 25° anteversion when perpendicular to the torso of the patient, and 40° abduction when perpendicular to the floor. 
     With the acetabular cup  97  in the acetabulum  68 , the alignment handle  92  is directly driven to medialize the acetabular cup  97 . In some embodiments, a cup impactor (e.g., P/N 20071010) is inserted through the cannula  88  and the tip of the alignment handle  92  until seated in the dimple of the threaded cup adapter  98 . With the shaft of the alignment handle  92  again tilted 10°-15° from vertical to account for the pelvic tilt of the patient on the table, the cup impactor is impacted until the acetabular cup  97  is firmly seated. An alignment guide (e.g., P/N 33330080) can be used for attachment on the cup impactor. With the acetabular cup  97  firmly seated, the threaded cup adapter  98  is unscrewed from the acetabular cup  97  using the hex tip of the cup impactor, and removed using a reamer basket holder  96 . 
     Referring to  FIG. 53 , in some embodiments, a screw centering tool or a depth gauge  100  is used in this step of placing the acetabular cup  97  or placing the screw as a following step in accordance with some embodiments. An exemplary depth gauge  100  is illustrated in  FIGS. 54-55 .  FIGS. 56-57  illustrate a method of using such a depth gauge  100  in some embodiments. The depth gauge  100  can be used for placing an acetabular cup  97  or any other implant  104 . 
     Referring to  FIG. 54 , an exemplary depth gauge  100  in accordance with some embodiments includes a straight body  102  having two ends: a first end  101  and a second end  103 . In some embodiments, the body  102  has a cylindrical shape, and is hollow throughout the entire depth gauge  100 . The end  101  may be a screw head itself, or adapted to be coupled with a screw head or a screw  105 . The end  101  may have equivalent screw geometry to a center of a hole thereon. In some embodiments, the end  101  has a geometry the same as that of screw head or a screw  105 , and is configured to allow centered placement in a hole, which may be for pre-drilling assessment of screw head position and seating. 
     As shown in  FIG. 54 , the end  103  in the exemplary depth gauge  100  has graduation or depth marks  103 - 1 . Referring to  FIG. 56 , in some embodiments, the depth gauge  100  has a suitable inner diameter, and is configured to be inserted into (or pass through) a cannula  88 . The depth gauge  100  is so configured that a Schanz pin  66  (as described above) can be inserted into or pass through the depth gauge  100 . In another word, the inner diameter of the depth gauge  100  is bigger than an outer diameter of the Schanz pin  66 , and the outer diameter of the depth gauge  100  is small than that of an inner diameter of the cannula  88 . 
     As shown in  FIGS. 56-57 , the depth gauge  100  is inserted into the cannula  88 , which is coupled with an implant  104  (or an acetabular cup  97 ) through a hole. The Schanz pin  66  is inserted into the depth gauge  100 . The depth marks  103 - 1  are configured to indicate and control the depth of insertion of a pin such as the Schanz pin  66 . The assembled structure is shown in  FIG. 57 . 
     The Schanz pin  66  is described here for illustration purpose only. Instead of a Schanz pin  66 , a drill  106  can be used in combination with the depth gauge  100  in some embodiments. In addition, as shown in  FIG. 58 , instead of having the depth marks  103 - 1  on one end of the depth gauge  100 , a drill  106  or the Schanz pin  66  can have the depth marks  107 , and is used in combination with one gauge  108  without depth marks, or the depth gauge  100 . 
     (13) Screw Placement 
     In some embodiments, a screw is placed into the acetabular cup through a pilot hole. The pilot hole can be drilled to a predetermined depth with the aid of a depth gauge for example the depth gauge  100 . In some embodiments, pilot holes for the placement of acetabular screws are created by inserting a long drill tube (e.g., P/N 20071012) through the cannula  88  until it engages the desired hole in the acetabular cup  97 . A screw drill (e.g., P/N 20071007) is then passed through the long drill tube. Using the measurement markings on the end of the screw drill, drilling is carried out to the desired depth. The screw drill and long drill tube are removed. Additionally, pilot holes can be created in a similar fashion using a drill tube (e.g., P/N 20071005) and a Schanz pin. When using this combination, the Schanz pin is advanced until bottoming on the drill tube. With continued revolutions of the pin, the threaded bone is stripped and a hole with a depth of 30 mm is created. In some embodiments, the screw drill (e.g., P/N 20071007) is only to be used with the long drill tube (e.g., P/N 20071012) and is not to be used with the drill tube (P/N 20071005) as the depth dimensions will not be accurate. 
     Screws can be held in position using a set of screw holding forceps (e.g., P/N 4820SH0000) through the main incision, and a ball joint screwdriver (e.g., P/N 20071002) or straight screwdriver (e.g., P/N 20071003) is attached to a ratchet screwdriver handle (e.g., P/N 2002QCRH) and passed through the cannula  88  to engage and tighten the screw(s). 
     (14) Trial Reduction 
     Referring to  FIG. 59 , a step of trial reduction is performed in some embodiments. Trials of femoral neck  110  and femoral head  116  are chosen by measuring the bone resection or using the components identified during pre-operative templating. For example, a PROFEMUR® Metal Trial Neck (e.g., P/Ns APA12102-APA12154) is placed into the seated broach while controlling the leg position. A set of forceps with angled tips can be used to facilitate this maneuver. A trial head (e.g., P/N APA02121-APA02154, or combination of P/Ns 41102800-41104800 and APAOTSS3-APAOTSL3 if large femoral heads with neck sleeves are used) in the socket and rotate its opening to a superior-posterior position. With the tip of the blunt trocar inserted into the top of the broach  50 , mate the trial neck  110  into the trial head  116 . During this maneuver, the surgeon controls the leg by pushing and translating the hip under direct visualization through the main incision, while an assistant controls the internal/external rotation of the hip by raising or lowering the foot or knee in some embodiment. 
     (15) Trial Disassembly 
     Referring to  FIG. 60 , a step of trial disassembly is performed in some embodiments. With the leg in the “home position,” an assistant can place the tip of a bone hook  82  or a bone hook tool  120  into the top of the broach  50  and applies lateral traction to the leg. The tip of a blunt trocar  90  is placed into the superior hole in the trial neck  110 . By engaging the side of the blunt trocar into the slot near the tip of the bone hook  82  and levering the two instruments against each other, the trial neck  110  is disassembled from the broach  50 . The trial components, including the femoral broach  50 , are then removed. 
     Referring to  FIGS. 61-63 , a bone hook tool  120  used has a bent tip  122  with an indented surface  124  in accordance with some embodiments.  FIG. 62  is an enlarged view of the bent tip  122 .  FIG. 63  is an enlarged view of the cross section  130  of the bent tip  122 . On the outer side of the bent tip  122 , the indented surface  124  is configured to be engaged with another tool  132  ( FIGS. 64-65 ) to remove or disassemble a part  136  such as a trial neck  110  without causing any dislocation ( FIGS. 66-67 ). Examples of another tool  132  include but are limited to a blunt trocar  90 . In another word, the bent tip  122  has a concaved surface, which is configured to accept a convex surface such as a round surface of the tool  132  such as the blunt trocar  90 . The indented surface  124  can be smooth or textured. In some embodiments, the indented surface  124  may optionally have marks  128 . 
     Referring to  FIGS. 64-67 , in an exemplary method of using the bone hook tool  120 , the tip end of the bone hook tool  120  is inserted into a hole  133  of a trial part or an implant such as a hip stem  134 . A suitable tool  132  (a second tool) such as a blunt trocar  90  is inserted into a hole  135  of a part  136  to be removed (such as a trial neck  110 ). In some embodiments, the second tool is a blunt trocar, and the part to be removed is a trial neck in a surgical procedure of replacing a hip joint. Meanwhile, the convex such as the round surface of the tool  132  is engaged with the indented surface  124  of the bone hook tool  120 . The handle or the arm of the tool  132  is rotated toward in such a way that the tip end of the bone hook tool  120  and the tip of the tool  132  are moved away from each other. The tool  132  is rotated against the indented surface of the bone hook tool  120 . The part to be removed is disassembled when the tip of the second tool are moved away from the tip end of the bone hook tool. The part  136  such as a trial neck  110  is then moved out of the hip stem  134 . In some embodiments, repeated rotation and movement back and forth may be used to achieve the step of disassembling the part  136  from the hip stem  134 . In some embodiments, the bone hook tool  120  having an indented surface  124  can be used to move against or disassemble a ball  138  away from the hip stem  134 , as shown in  FIG. 68 . 
     (16) Implant Assembly 
     Referring to  FIGS. 69-70 , a step of assembling implants is performed in some embodiments. After the associated tapers are cleaned and dried, a liner implant of the acetabular cup is then impacted into position using a cup impactor (through the cannula  88 ) and the appropriate liner impactor (e.g., P/Ns 20070023-20070025). A femoral stem is impacted into position. The depth of the femoral stem from the tip of the greater trochanter can be confirmed using the measurement markings on the end of a canal feeler. The femoral head implant (with neck sleeve if a large femoral head is selected) is placed into the acetabular cup with the opening in a superior-posterior position. In some embodiment, the femoral stem selected is modular, and the modular neck implant is placed into the femoral stem pocket using a set of forceps (e.g.,  140 ) with coated, angled tips to protect the neck taper. In some embodiments, to properly assemble and impact a modular neck, the modular neck and stem pocket tapers need to be clean and dry, and the modular neck can be seated using the offset neck impactor (e.g., P/N 20073009) with three very firm blows from a mallet. 
     With the tip of the blunt Trocar inserted into the top of the stem, the modular neck is mated into the femoral head after the neck and head tapers are cleaned and dried. As in the trial reduction maneuver, the surgeon controls the leg by pushing and translating the hip under direct visualization through the main incision, while an assistant controls the internal/external rotation of the hip by raising or lowering the foot or knee. Stability of the joint is verified by checking the range of motion, and proper leg length is also confirmed. 
     (17) Closure 
     The entire capsule has been preserved, and can be easily re-approximated in-line with the incision. Closure begins by approximating the joint capsule superiorly and inferiorly. If released, the  piriformis  is reattached to the posterior edge of the gluteus  medius . The remainder of the incision is closed in standard fashion. 
     Although the devices, systems, methods and tools have been described in terms of exemplary embodiments, they are not limited thereto. Rather, the appended claims should be construed broadly, to include other variants and embodiments of the disclosed devices, systems, and methods, which may be made by those skilled in the art without departing from the scope and range of equivalents of the devices, systems, methods and tools.