Query: Bone loss management in revision arthroplasty

title: Management of Bone Loss: Augments, Cones, Offset Stems
abstract: Trabecular metal augmentation has added new treatment options for severe proximal tibial bone defects in revision knee arthroplasty. Porous tantalum tibial cones provide mechanical support for the tibial component and have the potential for long term biologic fixation. These cones facilitate restoration of the proximal tibia metaphysis in Type 2 and 3 defects. Ten tantalum tibial cones were press fit into the prepared cavitary defect of a series of revision knee arthroplasties. Voids between the cone and host bone were filled with morselized grafting material. The core tibial component was cemented into the implanted tibial cone; fixation was enhanced with stem extensions, which were press fit in four knees and cemented in six knees. Extensions ranged from 75 200 mm with length dependent upon the residual bone quality. Offset stems were used in 3 tibias. At follow up (average 10 months) radiographic evaluation revealed no evidence of loosening or change in position. Strength, range of motion, and stability were comparable to previously reported series of revision arthroplasties. Trabecular metal cones can help reconstruct large cavitary defects and, along with stem extensions and offset stems, may eliminate the need for extensive bone grafting or structural allograft in revision knee arthroplasty.

title: Use of a trabecular metal patella for marked patella bone loss during revision total knee arthroplasty.
abstract: This study evaluates the short term results following patellar resurfacing with a trabecular metal patella shell in the setting of marked patellar bone loss at the time of revision total knee arthroplasty (TKA) Twenty consecutive patients undergoing revision TKA with the use of a trabecular metal patella were evaluated at a mean 23 month follow up. All patients had marked patellar bone loss at surgery precluding resurfacing with a standard cemented patellar button. Results were good or excellent in 17 of 20 patients. There were no displacements of any trabecular metal patella shells, and the fixation appeared excellent despite the poor quality of bone remaining. Complications included 3 patients with polar patella fractures postoperatively. Qualitatively, these results compare favorably with patellar resection arthroplasty in this setting.

title: Technique for impaction bone grafting of large bone defects in revision total knee arthroplasty.
abstract: Impaction bone grafting is an important tool in managing the irregularly sized and shaped bone defects observed in revision total knees. The technique is described in detail and includes tightly packing cancellous bone chips about an intramedullary stem and into the periprosthetic bone defects, then fully cementing a component in place. If needed, wire mesh can be used to contain bone defects. Results to date in 42 patients with 2 to 7 years of follow up are reported. They show the average flexion was 111 degrees; the final Knee Society score was 89 points, and there were no mechanical failures. There were 2 infections and 2 late periprosthetic fractures. The results have been encouraging, and this technique remains our procedure of choice for managing large bone defects in revision knee surgery.

title: Bone graft for revision hip arthroplasty: biology and future applications.
abstract: Revision total hip arthroplasty often presents surgeons with difficult bone loss problems. The selection of an appropriate bone graft is influenced by the size of the bone defect, the location, the biology of the bone graft site, and whether the graft is required for structural support. Autogenous bone graft remains the gold standard bone graft material but there only is a limited amount available and there is morbidity associated with the harvesting of these grafts. The most frequently used bone graft materials include autogenous iliac crest bone graft, cancellous allograft chips, demineralized bone matrix, and bulk structural allografts (femoral head, distal or proximal femoral allograft, whole acetabuli, and femoral strut grafts) It often is difficult to determine on plain radiographs whether nonstructural grafts actually incorporate into the host bone. Recently, attention has focused on the use of new materials for bone grafting including: new demineralized bone matrices, ceramics, autologous platelet concentrates, recombinant proteins, and stem cells. The purpose of this review was to assess the biologic potential of these nonstructural grafts in revision hip arthroplasty and their limitations. Are these agents actually incorporating into host bone? Future bone graft options, including tissue engineering and gene therapy will be discussed briefly.

title: Bone loss in total knee arthroplasty: graft augment and options.
abstract: The alternatives available for management of bone defects in total knee arthroplasty include prosthetic augments, autograft, allograft, and the use of bone cement. The selection of the augment technique should be based on the defect size, the patient age and life expectancy, and an assessment of the documented clinical results of each method. Prosthetic augments will address the vast majority of defects. The use of allograft is primarily indicated in the setting of major bone loss in revision knee arthroplasty, whereas the use of autograft is appropriate in the management of small defects in primary arthroplasty. Bone cement can be used for small defects if the stability of the implant is not compromised by the defect.

title: Results of revision total knee arthroplasty associated with significant bone loss.
abstract: The results of 40 revision total knee arthroplasties (TKAs) in 38 patients performed for aseptic failure with significant bone loss were reviewed. All knees were evaluated for at least two years, with an average of 41 months (range, two to nine years. Seventy five percent of the knees were considered excellent or good. Ten percent were considered failures. There were no infections. Overall complication rate was 30% of which wound complications were the most common. Revision TKA remains demanding, but results can be improved by (1) restoring the mechanical alignment of the knee with accurate component positioning; (2) filling all bone defects with bone, cement, or modular spacers; (3) using stems to assist in component support; and (4) adherence to soft tissue balancing and care.

title: Complications of ilioischial reconstruction rings in revision total hip arthroplasty.
abstract: The complications, management, and outcome of a consecutive series of 61 ilioischial reconstruction rings performed by 1 surgeon over a 15 year period are reported. Structural corticocancellous allografts were used in 48 cases. Twenty seven cases had no complications, 9 had medical complications, and 5 had complications related to femoral revision. Other complications included 4 sciatic and 2 peroneal nerve palsies, 4 rings that lost fixation, 1 possibly loose ring, 3 fractured flanges, 3 loose cups, 7 dislocations, and 3 deep infections. Success, defined as a stable reconstruction with no further acetabular revision and bone graft incorporation, was 76% We recommend a constrained acetabular liner to avoid dislocation in selected cases, slotting the ischial flange into bone for further ring stability and protection of the sciatic nerve.

title: Early failure of unicompartmental knee arthroplasty leading to revision.
abstract: The most common previously reported modes of failure of unicompartmental knee arthroplasty (UKA) in the first and second decades are polyethylene wear, progression of arthritis, and component loosening. The purpose of this study is to describe an early mechanism of failure of the medial UKA. Thirty two consecutive revisions from UKA to total knee arthroplasty were retrospectively reviewed. The predominant mode of failure observed in 15 (47% of 32 knees was medial tibial collapse. Of these, 87% were an all polyethylene design, and 7 of 15 failed in less than 16 months and required more complex reconstruction with stems, augments, and screws and cement. Increased tibial slope was associated with posterior tibial collapse. In our series, knees that failed by medial tibial collapse had more significant bone defects and required more complex reconstructions than is currently reported in the literature.

title: Risk of Subsequent Revision after Primary and Revision Total Joint Arthroplasty
abstract: BackgroundRevision is technically more demanding than primary total joint arthroplasty (TJA) and requires more extensive use of resources. Understanding the relative risk of rerevision and risk factors can help identify patients at high risk who may require closer postsurgical care. therefore evaluated the risk of subsequent revision after primary and revision TJA in the elderly (65 years or older) patient population and identified corresponding patient risk factors.Patients and MethodsUsing the 5% Medicare claims data set (1997 2006) we identified a total of 35,746 patients undergoing primary THA and 72,913 undergoing primary TKA; of these, 1205 who had THAs and 1599 who had TKAs underwent initial revision surgery. The rerevision rate after primary and revision TJAs was analyzed by the Kaplan Meier method. The relative risk of revision surgery for primary and revision TJAs was compared using hazard ratio analysis.ResultsThe 5 year survival probabilities were 95.9% 97.2% 81.0% and 87.4% for primary THA and TKA and revision THA and TKA, respectively. Patients with revision arthroplasty were five to six times more likely to undergo rerevision (adjusted relative risk, 4.89 for THA; 5.71 for TKA) compared with patients with primary arthroplasty. Age and comorbidities were associated with initial revision after primary THA and TKA.ConclusionsPatients should undergo stringent preoperative screening for preexisting health conditions and careful patient management and followup postoperatively so as to minimize the risk of an initial revision, which otherwise could lead to a significantly greater likelihood of subsequent rerevisions.

title: Classification and management of acetabular abnormalities in total hip arthroplasty.
abstract: Total hip arthroplasty, for both primary and revision operations, frequently involves bony abnormalities of the acetabulum. No standard nomenclature currently exists for the definition of acetabular deficiencies. A classification system is presented to assist in the preoperative evaluation and to provide a treatment protocol for these defects.