Benjamin K. Wilke

Long term outcomes of cemented endoprosthetic reconstruction for periarticular tumors of the distal femur

BACKGROUND In order to achieve an oncological margin during limb salvage surgery for tumors of the distal femur, part or the entire knee joint is frequently sacrificed. Endoprosthetics make limb salvage possible through restoration of a functional extremity. Currently there remains a paucity of data concerning their long-term outcomes and associated risk factors for failure. METHODS We identified 152 patients who underwent an endoprosthetic reconstruction for an oncological process of the distal femur between 1972 and 2013. The mean follow-up was 10years. Mean age and body mass index (BMI) were 39years and 25.8 respectively. The most common pathology was osteosarcoma (n=78, 48%). Outcomes were compared to a control group of 20,643 patients undergoing total knee arthroplasty (TKA) for degenerative joint disease (DJD) during the same time period. RESULTS The mean five-, 10-, 15-, 20-, and 25-year revision-free survival for an endoprosthesis was 76%, 63%, 51%, 36%, and 28%. Compared to the five-, 10-, 15-, 20-, and 25-year survival of 95%, 90%, 82%, 74%, and 67% for control TKAs (p<0.0001 at all-time points). Overall limb survival was 93%, with 11 patients undergoing amputation. There was no difference in implant survival comparing modular and custom endoprostheses. CONCLUSION The results of this study show that given the complexity of these operations, the rate of revision surgery following endoprosthetic replacement is high. Nevertheless, the use of these modular reconstructions leads to a high rate of limb salvage (93%) over a 25-year period at our institution. LEVEL OF EVIDENCE Level III.

Long-Term Survival of Semi-Constrained Total Knee Arthroplasty for Revision Surgery

Semi-constrained implants provide stability in the setting of soft-tissue deficiency in revision total knee arthroplasty (TKA). This study evaluated our institutions long-term survival results with a semi-constrained implant used in the revision TKA setting. 234 semi-constrained revision total knee arthroplasties were performed in 209 patients. The average follow-up was 9 years. Forty repeat revisions were performed. 5-year survival was 91% and 10-year survival was 81%. Male gender significantly increased the risk of revision. At 10 years the average range of motion, pain level, and Knee Society score improved significantly (P < 0.001). Ninety percent of patients reported an improvement in their knee. The semi-constrained implant used in revision knee arthroplasty has acceptable implant survival and functional outcomes in the long-term follow-up period.

Radiographic and Functional Outcomes Following Bilateral Ankle Fusions

Background: Ankle arthrodesis is considered to be a well-accepted technique for end-stage ankle arthritis. Our purpose was to evaluate outcomes of patients with bilateral ankle arthrodeses with attention to radiographic and functional outcomes. Methods: Medical records of 31 patients were reviewed from 1977 through 2007. All patients had 1 year of clinical follow-up after their contralateral ankle arthrodesis, with an average follow-up of 11.2 years following the initial arthrodesis. Pertinent patient demographics and information pertaining to the operative procedure, complications, and subsequent adjacent joint fusions was collected. Radiographs were reviewed for time to fusion and adjacent joint arthritis. Functional outcomes were measured using the Foot and Ankle Ability Measure (FAAM) and the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle and Hindfoot scale. Results: Ten females and 21 males underwent bilateral ankle fusions at an average age of 57 years at the time of the initial fusion. The contralateral fusion occurred on average 3.1 years following the initial fusion. Radiographic fusion occurred 12 weeks following the initial fusion and 14 weeks following the contralateral fusion. There was a significant increase (P = .0001) in the average AOFAS score postoperatively in both ankles. The average FAAM score at last follow-up was 70. Adjacent joint arthritis developed in the majority of patients; however, most of the patients were free from adjacent fusions and reported their function as “normal” or “nearly normal” at last follow-up. Conclusion: Bilateral ankle arthrodesis was an acceptable treatment option for patients with bilateral, end-stage ankle arthritis. Level of Evidence: Level IV, retrospective case series.

Femoral Bow Predicts Postoperative Malalignment in Revision Total Knee Arthroplasty

Diaphyseal bowing may compromise axial alignment in revision total knee arthroplasty (TKA). 277 patients undergoing revision TKA were evaluated for coronal bowing and hip-knee-ankle (HKA) axis. The mean femoral bow was 1.52° ± 0.18° varus (-10.1° to +8.4°). The mean tibial bow was 1.25° ± 0.13° valgus (-5.9° to +10°). HKA axis averaged 3.08° ± 0.35° varus preoperatively compared to 0.86° ± 0.25° varus postoperatively. Inter-rater and intra-rater reliability was high. Femoral bow greater than 4° significantly correlated with postoperative HKA axis malalignment (r = 0.402, P = 0.008). 39.7% of patients deviated 3° or greater from a neutral mechanical axis with a significant difference in femoral bow (0.94° ± 0.31°, P = 0.003). Diaphyseal bowing clearly has an important effect on postoperative limb alignment in revision TKA.

Delayed Avascular Necrosis and Fragmentation of the Lunate Following Perilunate Dislocation.

Perilunate and perilunate fracture dislocations are high-energy injuries with the wrist loaded in extension, ulnar deviation, and intercarpal supination. The force vector travels from a radial to a ulnar direction and can result in complex carpal instability. The diagnosis is often delayed, which can result in suboptimal outcomes. Nonoperative management can produce inferior results, with patients experiencing pain and weakness. Therefore, early treatment with open reduction and internal fixation is recommended to assess the osteochondral and ligamentous disruption and to achieve anatomic reduction of the carpus. Despite this, these patients can develop radiographic degenerative joint disease, which can be seen in up to 90% of cases. This can be due to difficulty in holding and maintaining carpal reduction. Increased radiodensity of the lunate following these injuries has been observed but is believed to be a transient phenomenon without risk of progression to avascular necrosis. This may be due to the blood supply of the lunate, which has varied patterns of intraosseous and extraosseous vascularity. The authors report a patient who developed avascular necrosis and delayed lunate fragmentation following a May-field Type IV perilunate dislocation. This finding highlights the importance of long-term follow-up with these patients.

Long-term survival of a semi-constrained implant following revision for infection.

Revision total knee arthroplasty (TKA) in prosthetic joint infections (PJI) is a challenging problem. We evaluated our institutional experience with a semi-constrained implant placed in a PJI setting. Seventy-eight TKAs in 75 patients with a history of a PJI were identified. The average follow-up was 7.5 years. Twenty-three (29%) underwent repeat revision surgery. Five and 10 year survivals were 71% and 64%, respectively. The most common reason for repeat revision surgery was recurrent infection (78%). Smoking and elevated BMI increased the risk of repeat revision surgery. Significant improvements were maintained long term in pain and range of motion (P < 0.01 and P = 0.02). In the absence of repeat infection, long term pain relief and improved function may be expected with the semi-constrained implant.

Late complications and long-term outcomes following aseptic revision of a hip arthroplasty performed for oncological resection.

Purpose In order to achieve an oncological margin during limb salvage surgery for tumours around the hip, part or the entire hip joint is frequently sacrificed. Hip arthroplasty restores a functional extremity and achieves limb salvage. Currently there is a paucity of data concerning the late complications, long-term survival, and the risks of re-revision following aseptic revision of a total hip arthroplasty (THA) performed following an oncological resection. Methods We identified 78 patients who underwent aseptic revision of a THA which was performed for an oncological process involving the hip from 1972 to 2006. All patients had a minimum 5 years of follow-up with a mean of 13 years. Outcomes were compared to 1,378 patients undergoing aseptic revision of a THA that was performed for a diagnosis of osteoarthritis. Results The mean 5-, 10-, 15-, and 20-year re-revision-free survival for an oncologic process of the hip was 100%, 85%, 69%, and 57%. Within this cohort, younger patients were at an increased risk of revision surgery. There was no difference in survivorship of the revision implant at any of the aforementioned time points between the oncologic and osteoarthritis cohorts. Patients with an oncologic diagnosis had a higher rate of dislocations, component wear, and loosening compared to the osteoarthritis group. Conclusion Late complications following revision surgery of THA performed for an oncologic resection are common. The results of this study provide information for counselling patients on implant survivorship and complications following aseptic revision THA after index surgery for an oncologic indication.

What Factors Influence the Outcome of Surgically Treated Soft Tissue Sarcomas of the Hand and Wrist

Background: Soft tissue sarcomas (STS) of the hand are exceedingly rare. The aim of this study was to review our institution’s experience with STS of the hand to identify factors affecting outcomes and survivorship. Methods: We retrospectively reviewed the records of 46 hand STS treated with definitive surgery at our institution between 1992 and 2013. Pertinent demographics as well as information regarding the surgical procedure, and disease status at latest follow-up were reviewed. Mean age at diagnosis was 38 years with a mean follow-up of 5 years. Results: The most common tumor subtypes were epithelioid (n = 10) and synovial sarcoma (n = 8). Sixty-one percent were superficial in location. Thirty-three patients had had a nononcologic resection prior to definitive surgical treatment at our institution. Ultimately, negative margins were obtained in all cases. Local recurrence was observed in 5 patients and distant metastases in 14 patients. Tumor sizes ≥2 cm, American Joint Committee on Cancer (AJCC) grade, and depth of the tumor were found to adversely affect the outcome in terms of disease-free and overall survival. Reexcision of an inadvertently excised tumor at an outside institution did not adversely affect the outcome. The 10-year overall and disease-free survival was 72% and 63%. Conclusions: Local recurrence after a wide excision was observed infrequently; however, distant disease was relatively common. Tumors with a size ≥2 cm were associated with a worse disease-free and overall survival, highlighting the aggressive nature of these tumors.

Proximal Femoral Allograft Prosthetic Composites; Do They Really Restore Bone? A Retrospective Review of Revision Allograft Prosthetic Composites

BACKGROUND Large bone deficiencies are a challenging problem, historically treated with an allograft-prosthetic composite (APC) or megaprosthesis. There were several advantages of the APC compared with early megaprostheses, including the theoretical benefit of restoring bone stock. To our knowledge, there are no studies that have evaluated this claim. Our purpose was to review our institutions experience with APCs of the proximal femur that underwent revision for an aseptic cause and determine if the allograft bone was retained or removed during the revision procedure. METHODS We identified 203 proximal femoral allograft prosthetic composites placed from 1988 through 2014. Twenty-seven of these patients underwent a revision because of an aseptic cause. Three categories were devised to classify the amount of allograft retention: type A, complete allograft retention; type B, partial retention; and type C, no allograft retention. RESULTS The mean time from the initial APC to revision surgery was 5 years. The most common indication for revision included failure of the allograft (loosening or fracture). At the time of revision, there were 3 type A cases (11%), 4 type B cases (15%), and 20 type C cases (74%). Three of the 4 type B cases used the retained allograft as a strut graft around a newly inserted megaprosthesis. CONCLUSION The results of this study are contradictory to previous literature that suggests APCs restore bone stock. In this series, the allograft was retained in only a small percentage of cases when the APC was revised for an aseptic cause. LEVEL OF EVIDENCE IV.

Treatment of Unicameral Bone Cysts of the Proximal Femur With Internal Fixation Lessens the Risk of Additional Surgery

Little data exist to guide the treatment of unicameral bone cysts in the proximal femur. Methods of treatment include corticosteroid injections, curettage and bone grafting, and internal fixation. The authors completed a multi-institutional, retrospective review to evaluate their experience with proximal femoral unicameral bone cysts. They posed the following questions: (1) Does internal fixation reduce the risk of further procedures for the treatment of a unicameral bone cyst? (2) Is radiographic healing faster with internal fixation? Following institutional review board approval, the authors conducted a retrospective review of 36 patients treated for a unicameral bone cyst of the proximal femur at their institutions between 1974 and 2014. Medical records and radiographs were reviewed to identify patient demographics and treatment outcomes. Tumor locations included femoral neck (n=13), intertrochanteric (n=16), and subtrochanteric (n=7). Initial treatment included steroid injection (n=2), curettage and bone grafting (n=9), and internal fixation with curettage and bone grafting (n=25). Mean time was 9 months to radiographic healing and 15 months to return to full activity. The number of patients requiring additional surgeries was increased among those who did not undergo internal fixation. There was no difference in time to radiographic healing. However, time to return to normal activities was reduced if patients had received internal fixation. A significant reduction in additional procedures was observed when patients had been treated with internal fixation. Although this did not influence time to radiographic healing, patients did return to normal activities sooner. Internal fixation should be considered in the treatment of proximal femoral unicameral bone cysts. [Orthopedics. 2017; 40(5):e862-e867.].