Patent Publication Number: US-2022218364-A1

Title: Opening and closing wedge osteotomy guide and method

Description:
CROSS REFERENCE TO RELATED PATENT APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 17/157,146, filed Jan. 25, 2021, which is a continuation of U.S. patent application Ser. No. 14/994,362, filed Jan. 13, 2016, both titled OPENING AND CLOSING WEDGE OSTEOTOMY GUIDE AND METHOD, which claims the benefit of U.S. Provisional Application No. 62/103,397, filed Jan. 14, 2015, titled OSTEOTOMY GUIDE AND METHOD, all of which are incorporated herein by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to methods, implants, and instruments for performing an osteotomy on a bone. 
     BACKGROUND 
     Various conditions may affect skeletal joints such as the deterioration, elongation, shortening, or rupture of soft tissues, cartilage, and/or bone associated with the joint and consequent laxity, pain, and/or deformity. It is often desirable to change the angular alignment of a bone or a portion of a bone to restore function and/or reduce pain. To this end, various osteotomy procedures and instruments have been proposed. For example, osteotomies have been performed throughout the body to make various angular adjustments such as in a tibia, fibula, femur, pelvis, humerus, ulna, radius, metacarpal, metatarsal, and other bones. Prior osteotomies couple angular correction and change in bone length in ways that often produce undesirable results. 
     SUMMARY 
     The present invention provides methods, implants, and instruments for performing an osteotomy on a bone. 
     In one example of the invention, a method of performing an osteotomy on a bone includes removing a portion of bone from a first side of the bone to create a gap on the first side of the bone; making a cut on a second side of the bone, opposite the first side; and rotating the bone from a first position to a second position to close the gap on the first side of the bone and open the cut on the second side of the bone to create a gap on the second side of the bone. 
     In another example of the invention, a method of performing an osteotomy on a metatarsus of a first ray of the human foot includes positioning an osteotomy guide adjacent the metatarsus; guiding a cutter to remove a portion of bone from a first side of the metatarsus to create a gap on the first side of the metatarsus; guiding a cutter to make a cut on a second side of the metatarsus, opposite the first side; rotating the metatarsus from a first position to a second position to close the gap on the first side of the metatarsus and open the cut on the second side of the metatarsus to create a gap on the second side of the metatarsus; and filling the gap created on the second side of the metatarsus. 
     In another example of the invention, an osteotomy guide includes a guide body having a proximal end, a distal end, and first and second sides. The first side includes first and second guide surfaces that converge from the first side toward the second side. The first and second guide surfaces are operable to guide a cutter to remove a wedge of bone from a first side of a bone. The second side includes a third guide surface extending toward but stopping short of the first and second guide surfaces. The third guide surface being operable to guide a cutter to make a cut on a second side of a bone. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various examples of the present invention will be discussed with reference to the appended drawings. These drawings depict only illustrative examples of the invention and are not to be considered limiting of its scope. 
         FIG. 1  is side elevation view of a foot illustrating anatomic reference planes and relative directions; 
         FIG. 2  is a lateral view of a foot illustrating dorsiflexion and plantar flexion; 
         FIG. 3  is a coronal view of a foot illustrating inversion and eversion; 
         FIG. 4  is a dorsal view illustrating bones, tendons, and ligaments of the foot; 
         FIG. 5  is a plantar view illustrating bones, tendons, and ligaments of the foot; 
         FIG. 6  is a perspective view illustrating bones, tendons, and ligaments of the foot; 
         FIG. 7  is a medial view of the MTP joint of the first ray of the foot; 
         FIG. 8  is a sectional view taken along line  8 - 8  of  FIG. 7 ; 
         FIG. 9  is a dorsal view of the MTC joint of the first ray of the foot; 
         FIG. 10  is a medial view of the MTC joint of the first ray of the foot; 
         FIG. 11  is a dorsal view illustrating deformity of the foot; 
         FIG. 12  is a plantar view illustrating deformity of the foot; 
         FIG. 13  is a sectional view similar to that of  FIG. 8  but illustrating deformity of the foot; 
         FIG. 14  is an isometric view of an osteotomy guide according to the present invention; 
         FIG. 15  is a top plan view of the osteotomy guide of  FIG. 14 ; 
         FIG. 16  is a side elevation view of the osteotomy guide of  FIG. 14 ; 
         FIG. 17  is a front elevation view of the osteotomy guide of  FIG. 14 ; 
         FIGS. 18-21  are dorsal views illustrating the use of the osteotomy guide of  FIG. 14  to correct a deformity; 
         FIG. 22  is a medial view of the corrected deformity; 
         FIG. 23  is an isometric view showing the top of an osteotomy guide according to the present invention; 
         FIG. 24  is a top plan view of the osteotomy guide of  FIG. 23 ; 
         FIG. 25  is a front elevation view of the osteotomy guide of  FIG. 23 ; 
         FIG. 26  is a side elevation view of the osteotomy guide of  FIG. 23 ; 
         FIG. 27  is an isometric view showing the bottom of the osteotomy guide of  FIG. 23 ; and 
         FIG. 28  is a top plan view showing a set of osteotomy guides like that of  FIG. 23  having various correction angles and configured for left and right corrections. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following illustrative examples describe implants, instruments and techniques for performing an osteotomy on a bone. The present invention may be used to perform osteotomies on any bone including but not limited to a tibia, fibula, femur, pelvis, humerus, ulna, radius, metacarpal, and metatarsal. However, for convenience, the invention will be illustrated with reference to a metatarsal bone of the first ray of a human foot. 
       FIG. 1  illustrates the orientation of anatomic planes and relative directional terms that are used for reference in this application. The coronal plane  10  extends from medial  12  (toward the midline of the body) to lateral (away from the midline of the body) and from dorsal  14  (toward the top of the foot) to plantar  16  (toward the sole of the foot). The sagittal plane  18  extends from anterior  20  (toward the front of the body) to posterior  22  (toward the back of the body) and from dorsal  14  to plantar  16 . The transverse plane  24  extends anterior  20  to posterior  22  and medial to lateral parallel to the floor  26 . Relative positions are also described as being proximal or distal where proximal is along the lower extremity toward the knee and distal is along the lower extremity toward the toes. The following examples serve to demonstrate the relative directions. The great toe is medial of the lesser toes and the fifth toe is lateral of the great toe. The toes are distal to the heel and the ankle is proximal to the toes. The instep is dorsal and the arch is plantar. The toenails are dorsal and distal on the toes. 
       FIG. 2  illustrates dorsiflexion  23  in which the toes are moved dorsally, or closer to the shin, by decreasing the angle between the dorsum of the foot and the leg and plantar flexion  25  in which the toes are moved plantar, or further away from the shin, by increasing the angle between the dorsum of the foot and the leg. For example when one walks on their heels, the ankle is dorsiflexed and when one walks on their toes, the ankle is plantar flexed. 
       FIG. 3  illustrates inversion  27  in which the sole of the foot is tilted toward the sagittal plane or midline of the body and eversion  29  in which the sole of the foot is tilted away from the sagittal plane. 
       FIGS. 4-10  illustrate the arrangement of the bones within the foot  30 . A right foot is illustrated. Beginning at the proximal example of the foot, the heel bone or calcaneus  32  projects plantar. The talus  34  is dorsal to the calcaneus  32  and articulates with it at the talocalcaneal or subtalar joint. Dorsally, the talus articulates medially with the tibia  36  and laterally with the fibula  38  at the ankle joint. Distal to the ankle are the navicular bone  40  medially and the cuboid bone  42  laterally which articulate with the talus and calcaneus respectively. The navicular bone  40  and cuboid bone  42  may also articulate with one another at the lateral side of the navicular bone and the medial side of the cuboid bone. Three cuneiform bones lie distal to the navicular bone and articulate with the navicular bone and one another. The first, or medial, cuneiform  44  is located on the medial side of the foot  30 . The second, or intermediate, cuneiform  46  is located lateral of the first cuneiform  44 . The third, or lateral, cuneiform  48  is located lateral of the second cuneiform  46 . The third cuneiform  48  also articulates with the cuboid bone  42 . Five metatarsals  50 ,  52 ,  54 ,  56 ,  58  extend distally from and articulate with the cuneiform and cuboid bones. The metatarsals are numbered from I to 5 starting with the first metatarsal  50  on the medial side of the foot and ending with the fifth metatarsal  58  on the lateral side of the foot  30 . 
     The first metatarsal  50  articulates with the first cuneiform  44  at a metatarso cuneiform (MTC) joint  51 . The second metatarsal  52  articulates with the first, second and third cuneiforms  44 ,  46 ,  48  and may articulate with the first metatarsal as well. Five proximal phalanges  60 ,  62 ,  64 ,  66 ,  68  extend distally from and articulate with the five metatarsals respectively. The first proximal phalanx  60  articulates with the first metatarsal  50  at a metatarsophalangeal (MTP) joint  61 . One or more distal phalanges  70 ,  72 ,  74 ,  76 ,  78 ,  80  extend distally from the proximal phalanges. The first metatarsal  50 , first proximal phalanx  60 , and, first distal phalanx  70  together are referred to as the first ray of the foot. Similarly, the metatarsal, proximal phalanx, and distal phalanges corresponding to the lesser digits are referred to as the second through fifth rays respectively. 
       FIG. 4  is a dorsal view illustrating bones, tendons and ligaments of the foot. Plantar structures illustrated in  FIG. 5  are omitted from  FIG. 4  for clarity. The extensor hallucis longus muscle originates in the anterior portion of the leg, the extensor hallucis longus tendon  80  extends distally across the ankle and along the first ray to insert into the base of the distal phalanx  70 . The tibialis anterior muscle originates in the lateral portion of the leg and the tibialis anterior tendon  82  extends distally across the ankle and inserts into the first cuneiform  44  and first metatarsus  50  at the first MTC joint  51  where it contributes to the MTC capsular structure  84  ( FIGS. 9 and 10 ). A transverse intermetatarsal ligament  83  inserts into the capsule of the MTP joint such that it connects the heads of the first through fifth metatarsal bones. In  FIG. 4 , only the connection between the first and second metatarsal bones  50 ,  52  is shown. 
       FIG. 5  is a plantar view illustrating bones, tendons, and ligaments of the foot. Dorsal structures shown in  FIG. 4  are omitted from  FIG. 5  for clarity. The peroneus longus muscle originates at the head of the fibula and its tendon  86  passes posteriorly around the lateral malleolus  88  of the ankle, around the cuboid notch  90  on the lateral side of the cuboid bone  42 , along the peroneal sulcus  92  on the plantar surface of the cuboid bone  42 , and inserts into the first metatarsal  50 . The flexor hallucis brevis muscle  94  originates from the cuboid  42  and third cuneiform  48  and divides distally where it inserts into the base of the proximal phalanx  60 . 
     Medial and lateral sesamoid bones  96 ,  98  are present in each portion of the divided tendon at the MTP joint  61 . The sesamoids  96 ,  98  articulate with the planar surface of the metatarsal head in two grooves  100 ,  102  separated by a rounded ridge, or crista  104  ( FIG. 8 ). The flexor hallucis longus muscle originates from the posterior portion of the fibula  38 . The flexor hallucis longus tendon  106  crosses the posterior surface of the lower end of the tibia, the posterior surface of the talus, runs forward between the two heads of the flexor hallucis brevis  94 , and is inserted into the base of the distal phalanx  70  of the great toe. 
       FIG. 7  is a medial view of tendons at the MTP joint  61  of the first ray. A medial collateral ligament  108  originates from the head of the first metatarsus  50  and inserts into the proximal phalanx  60 . A medial metatarsosesamoid ligament  110  originates from the head of the first metatarsus  50  and inserts into the medial sesamoid bone  96 . Similar collateral and metatarsosesamoid ligaments are found on the lateral side of the first MTP joint. The flexor hallucis brevis  94  is shown inserting into the sesamoids  96 ,  98 . Ligamentous fibers extend further distally in the form of a phalangealsesamoid ligament  112  from the sesamoids to the proximal phalanx  60 . 
       FIG. 8  is a sectional view taken along line  8 - 8  of  FIG. 7  showing the metatarsal head  50 , the tendon of the extensor hallucis longus  80 , the medial and lateral sesamoid bones  96 ,  98 , the grooves  100 ,  102  in which the sesamoids articulate, the crista  104  separating the grooves, the flexor hallucis longus  106 , the abductor hallucis  114 , and the adductor hallucis  116 . 
       FIG. 9  is a dorsal view showing the dorsal capsular structure  84  of the MTC joint  51  of the first ray including the insertion of the tibialis anterior tendon  82 . 
       FIG. 10  is a medial view of the MTC joint  51  of the first ray showing the medial capsular structure  118 . 
       FIGS. 11-13  illustrate deformities of the first ray. In a dorsal view, as shown in  FIG. 11 , an intermetatarsal angle (IMA)  120  may be measured between the longitudinal axes of the first and second metatarsal bones  50 ,  52 . The angle is considered abnormal when it is 9 degrees or greater and the condition is known as metatarsus primus varus (MPV) deformity. A mild deformity is less than 12 degrees, a moderate deformity is 12-15 degrees, and a severe deformity is greater than 15 degrees. Similarly, a hallux valgus angle (HVA)  122  may be measured between the longitudinal axes of the first metatarsus  50  and the first proximal phalanx  60  at the MTP joint  61 . The angle is considered abnormal when it is 15 degrees or greater and the condition is known as a hallux valgus (HV) deformity. A mild deformity is less than 20 degrees, a moderate deformity is 20 to 40 degrees, and a severe deformity is greater than 40 degrees. 
     MPV and HV often occur together as shown in  FIGS. 11-12 . As the deformities progress several changes may occur in and around the MTC and MTP joints. Referring to  FIG. 13 , as the IMA and HVA increase, the extensors  80 , flexors  106 , abductors  114 , and adductors  116  of the first ray (along with the sesamoids  96 ,  98 ) are shifted laterally relative to the MTP joint. The laterally shifted tendons exert tension lateral to the MTP joint creating a bow string effect (as best seen in  FIGS. 11 and 12 ) that tends to cause the deformities to increase. The lateral shift of the sesamoids  96 ,  98  is often accompanied by erosion of the crista. The abnormal muscle forces cause the metatarsus  50  to pronate, or in other words, rotate so that the dorsal example of the bone moves medially and the plantar example moves laterally. Rotation in the opposite direction is referred to as supination. Soft tissues on the medial side of the MTP joint and lateral side of the MTC joint attenuate, through lengthening and thinning, thus weakening the capsule and permitting the deformities to progress. Soft tissues on the opposite sides of the capsule tend to shorten, thicken and form contractures making it difficult to reduce the joints to their normal angular alignment. 
     More generally, deformities of the first ray may include metatarsus primus varus, hallux valgus, abnormal pronation, abnormal supination, abnormal dorsiflexion, and/or abnormal plantarflexion. These deformities correspond to three different planar rotations. Metatarsus primus varus and hallux valgus result from rotations in the transverse plane  24 . Pronation and supination are rotation in the coronal plane  10 . Dorsiflexion and plantar flexion are rotation in the sagittal plane. 
     The terms “suture” and “suture strand” are used herein to mean any strand or flexible member, natural or synthetic, able to be passed through material and useful in a surgical procedure. The term “transverse” is used herein to mean crossing as in non-parallel. 
     The present invention provides methods and devices for performing an osteotomy on a bone.  FIGS. 14-17  depict an illustrative osteotomy guide  200  according to the present invention. The guide  200  includes a guide body  202  having a proximal end  204 , a distal end  206 , a first side  208 , a second side  210  opposite the first side  208 , an upper surface  4 , and a lower surface  211 . First and second guide surfaces  212 ,  214  are formed on the first side  208  of the guide body and are separated by a guide angle  217 . The first and second guide surfaces  212 ,  214  converge from the first side  208  toward the second side  210  of the guide body and define a wedge shaped slot  215 . The first and second guide surfaces are operable to guide a cutter to remove a wedge of bone from a first side of a bone. The open wedge shaped slot  215  shown in the illustrative example of  FIGS. 14-17  facilitates visualization of the bone to be cut and removal of the cut bone. A third guide surface  216  is formed on the second side  210  of the guide body. The third guide surface  216  is operable to guide a cutter to make a cut on a second side of a bone. For example, in the illustrative example of  FIGS. 14-17 , the first, second, and third guide surfaces  212 ,  214 ,  216  include planar surfaces against which a cutter may be supported to guide the cutter to make a cut coplanar with the guide surface. In the illustrative example of  FIGS. 14-17 , an optional fourth guide surface  218  is provided parallel to and opposite the third guide surface  216  to further constrain a cutter. The third and fourth guide surfaces  216 ,  218  define a parallel slot  220  between them operable to constrain a saw blade between them to a single plane. The third and fourth guide surfaces  216 ,  218  are spaced apart so that slot  220  receives a cutter, e.g. a saw blade, in planar sliding relationship. Similarly, rather than forming an open wedge, the first and second guide surfaces  212 ,  214  may be opposed by fifth and sixth guide surfaces to define narrow slots separated by the guide angle  217  and able to receive a cutter in planar sliding relationship. The guide surfaces  212 ,  214 ,  216  converge toward the center of the guide  200  but are spaced apart at the center by a solid portion  238 . The solid portion  238  of the guide acts as a cutter stop to prevent a cutter from cutting all the way through the bone so that a central portion of the bone is preserved to act as a hinge about which the bone may be rotated. 
     The guide body  202  includes one or more fixation elements for attaching the guide to a bone to be cut. In the illustrative example of  FIGS. 14-17 , a plurality of fixation elements are provided with at least one fixation element proximal to the guide surfaces and at least one fixation element distal to the guide surfaces. In the illustrative example of  FIGS. 14-17 , the fixation elements are in the form of holes  222 ,  224 ,  226 ,  228  through the guide body  202  from the upper surface  209  to the lower surface  211  and operable to receive pins, nails, screws or other suitable fasteners to attach the guide body  202  to a bone. In the illustrative example of  FIGS. 14-17 , three holes  222 ,  224 ,  226  are provided proximal to the guide surfaces  212 ,  214 ,  216  and one hole  228  is provided distal to the guide surfaces. 
     The lower surface  211  of the guide body  202  is curved to form a concave profile  230  to engage a curved outer surface of a bone. In the illustrative example of  FIGS. 14-17 , the third guide surface  216  is coplanar with the second guide surface  214  to aid in producing a bone wedge that will better fit the opposite side of the bone as will be explained in more detail below. The guide surfaces  212 , 214 ,  216  guide a cutter to make cuts that converge toward the center of the guide  200  from each of the first and second sides  208 ,  210  but stop short of meeting and completely bisecting the bone. This leaves a portion of bone intact toward the center of the bone. 
     A reference mark  232  is provided to indicate the amount of angular correction that the guide  200  will produce. The reference mark  232  is angled relative to a first, longitudinal axis  234  of the guide by the same amount as the first guide surface  212  is angled relative to a second axis  236  perpendicular to the first axis  234 . In the illustrative example of  FIGS. 14-17 , the first axis  234  extends proximodistally and the fixation holes  222 ,  224 ,  226 , and  228  are aligned on the first axis  234 . The second axis  236  is perpendicular to the first axis  234  and extends between the first and second sides  208 ,  210 . 
     The osteotomy guide  200  may include a set of two or more osteotomy guides, each of which has a different guide angle  217 . The osteotomy guide  200  may include guides with mirrored guide surface positions. For example, on one osteotomy guide, the first and second guide surfaces  212 ,  214  may form a wedge on the first side  208  of the guide (as shown) while on another guide, the first and second guide surface may form a wedge on the second side  210  of the guide. For example, a right guide may be provided for cutting a bone on the right side of a patient&#39;s body and a mirrored left guide may be provided for cutting a bone on the left side of a patient&#39;s body. For example, an osteotomy guide for guiding the formation of an osteotomy for correcting an MPV deformity of the first ray of a human foot may be provided in a right configuration with the wedge producing first and second guide surfaces  212 ,  214  on the first side  208  of the guide corresponding to the lateral side of a right foot metatarsus and a left configuration with the wedge producing first and second guide surfaces  212 ,  214  on the second side  210  of the guide corresponding to the lateral side of a left foot metatarsus. Alternatively, the guide may have sufficient symmetry to allow it to be rotated  180  degrees for use on a left or right bone. 
       FIGS. 18-22  illustrate a method of performing an osteotomy on a bone. While the osteotomy guide of  FIGS. 14-17  is well suited to performing the illustrative osteotomy, the osteotomy may be performed using another guide or no guide at all with the cuts being made freehand. However, the illustrative method will be described being performed with the illustrative guide of  FIGS. 14-17  along with advantages that result from using such a guide. 
     In an illustrative method according to the present invention, a portion of bone is removed from a first side of a bone to create a gap on the first side of the bone. A cut is made on a second side of the bone, opposite the first side. The bone is rotated from a first, initial position in which the bone was cut to a second position to close the gap on the first side of the bone and open the cut on the second side of the bone to create a gap on the second side of the bone. The bone may be cut through such that the cuts on opposite sides of the bone meet. Alternatively, the cuts may stop short of meeting so that a portion of bone remains connecting the proximal and distal bone portions and about which the bone may rotate or bend. The bone may be fixed in the second position to heal. The gap on the second side of the bone may be filled to facilitate bone healing. 
     For example, the gap may be filled with a filler including autograft tissue, allograft tissue, xenograft tissue, plastic, metal, or ceramic. The portion of bone removed from the first side of the bone may be used to fill the gap created on the second side of the bone to facilitate bone healing. For example, a wedge of bone may be removed from the first side of the bone and inserted into a wedge shaped gap formed on the second side of the bone when the bone is rotated. 
     The bone may be secured in the second position with a fixation element such as, for example, a plate, pin, screw, or other fixation element. 
     In the illustrative method of  FIGS. 18-22 , an osteotomy guide  200  is positioned over a bone to be cut. In the illustrative method of  FIGS. 18-22 , the bone is a first metatarsus  300  of a human foot having an MPV angular deformity. The osteotomy guide  200  is selected to have a guide angle  217  corresponding to a desired amount of MPV angular correction and a configuration appropriate for the operative side of the body. In the illustrative example of  FIGS. 18-22 , the deformity is on a right foot so it is desirable to move the distal end of the metatarsus  300  laterally. Therefore, a guide  200  is selected with the wedge producing first and second guide surfaces  212 ,  214  on the first or lateral side  208  of the guide. One or more pins, screw, nails, or other fixation members are inserted through the osteotomy guide  200  and into the bone to secure the osteotomy guide  200  to the bone. In the illustrative example of  FIGS. 18-22 , two pins  302 ,  304  are inserted through two holes  224 ,  226  in the proximal portion of the osteotomy guide  200  proximal to the guide surfaces. The pins secure the osteotomy guide  200  to the metatarsus  300 . Utilizing two pins and two holes advantageously constrains the osteotomy guide  200  rotationally relative to the metatarsus  300 . An additional pin may be placed in hole  222  to attach the osteotomy guide  200  to the first cuneiform bone  306 . 
     Referring to  FIG. 19 , a cutter is guided by first and second guide surfaces  212 ,  214  to remove a wedge  308  of bone from the lateral side of the metatarsus  300  leaving a lateral gap  309  and to make a cut  310  on the medial side of the metatarsus. 
     The central solid portion  238  of the guide prevents the cuts from the medial and lateral sides from meeting so that a portion of bone  312  is preserved as seen in  FIG. 20 . The distal portion of the metatarsus is rotated about the portion of bone  312  to close the lateral gap  309  and open the cut  310  on the medial side creating a medial gap  311 . The wedge  308  from the lateral side is inserted into the medial gap  311 . The bone is supported for healing with a plate  314  and screws  316 . Optionally, a fixation member may be placed through the distal fixation hole  228  in the guide after the bone is rotated to support the bone in the rotated position to facilitate grafting the medial gap and placing the plate  314  and screws  316 . The completed correction is shown in  FIGS. 21 and 22 . 
       FIGS. 23-27  depict another example of an illustrative osteotomy guide  400  configured generally like that of  FIG. 14 . The guide  400  includes a guide body  402  having a proximal end  404 , a distal end  406 , a first side  408 , a second side  410  opposite the first side  408 , an upper surface  409 , and a lower surface  411 . First and second guide surfaces  412 ,  414  are formed on the first side  408  of the guide body and are separated by a guide angle  417 . The first and second guide surfaces  412 ,  414  converge from the first side  408  toward the second side  410  of the guide body and define a wedge shaped slot  415 . A third guide surface  416  is formed on the second side  410  of the guide body. In the illustrative example of  FIGS. 23-27 , an optional fourth guide surface  418  is provided parallel to and opposite the third guide surface  416 . The third and fourth guide surfaces  416 ,  418  define a parallel slot  420  between them operable to constrain a saw blade between them. The guide surfaces  412 ,  414 ,  416  converge toward the center of the guide  400  but are spaced apart at the center by a solid portion  438 . 
     The guide body  402  includes one or more fixation elements for attaching the guide to a bone to be cut. In the illustrative example of  FIGS. 23-27 , a plurality of fixation elements is provided in the form of holes  422 ,  424 ,  426 ,  428  through the guide body  402  from the upper surface  409  to the lower surface  411  and operable to receive pins, nails, screws or other suitable fasteners to attach the guide body  402  to a bone. 
     The lower surface  411  of the guide body  402  is curved to form a concave profile  430  to engage a curved outer surface of a bone. 
     In the illustrative example of  FIGS. 23-27 , first and second walls  450 ,  452  are provided on the first and second sides  408 ,  410 . The first wall  450  caps the end of the wedge shaped slot  415  and the second wall  452  caps the end of the parallel slot  420 . The first and second walls  450 ,  452  project above the upper surface  409  to terminal ends  454 ,  456 . A saw blade guided by the one of the guide surfaces  412 ,  414 ,  416 ,  418  defining the slots  415 ,  420  is constrained to limited angles by impinging on the guide surfaces, the solid portion  438 , the walls  450 ,  452  and terminal ends  454 ,  456 . By adjusting the width and height of these features and the width and length of the saw blade, it is possible to protect structures surrounding the bone from being cut from accidental contact with the saw blade. 
     Reference marks  432 ,  434  are provided to indicate the amount of angular correction that the guide  400  will produce. A correction reference mark  432  is angled relative to an axial reference mark  434  by the same amount as the first guide surface  412  is angled relative to a second axis  436  perpendicular to the axial reference mark  434 . The reference marks give an immediate visual indication of the amount and direction of angular correction. The correction reference mark  432  is preferably labeled “Correction” for clarity. Additional text indicators may be provided such as a direction indicator  460  and a magnitude indicator  462 . For example, in the illustrative example of  FIGS. 23-27 , the direction indicator  460  contains the text “Left” or “Right” to indicate the direction of the correction or the side of the patient&#39;s body on which it is to be used. The magnitude indicator  462  contains text indicating the number of degrees of angular correction that the guide  400  provides. In the illustrative example of  FIGS. 23-27 , the guide further includes a label adjacent the proximal end  404  indicating where to position the proximal end. For example, in the illustrative example of  FIGS. 23-27 , the proximal end is labeled “Joint Line” to indicate that for a metatarsal corrective osteotomy, the proximal end should be positioned at the joint line of the MTC joint. In the illustrative example of  FIGS. 23-27 , the fixation holes  422 ,  424 ,  426 ,  428  are positioned to receive pins into the metatarsus with two proximal to the osteotomy cuts and two distal to the osteotomy cuts. 
     Referring to  FIG. 28 , a set  500  of osteotomy guides  504 ,  506 ,  508 ,  510 ,  512 ,  514  are provided in a tray  502 . In the illustrative example of  FIG. 28 , three “Left” guides  504 ,  508 ,  512  and three “Right” guides  506 ,  510 ,  514  are provided. The left guides are provided in three corrective angles corresponding to 5, 10, and 15 degrees of angular correction. The right guides are also provided with 5, 10, and 15 degrees of angular correction. 
     Various examples have been provided to illustrate the present invention. It will be understood that variations may be made and still be within the scope of the invention.