What Are the Complication Rates and Factors Associated With Total Femur Replacement After Tumor Resection? Findings From the Japanese Musculoskeletal Oncology Group
Authors: Mori Tomoaki , Kobayashi Eisuke , Sato Yasunori , Takenaka Satoshi , Endo Makoto , Nakamura Tomoki , Morii Takeshi , Yoshida Yukihiro , Ueda Takafumi , Kawano Hirotaka , Kawai Akira 
Published: October 2023

Abstract

Background
Patients undergoing massive tumor resection and total femur replacement (TFR) face a substantial risk of hip dislocation and infection, often resulting in multiple implant revisions or hip disarticulation. These complications can impact their independence and prognosis. Additionally, their shorter life expectancy is influenced by challenges in achieving local radical resection and controlling metastases. Identifying suitable candidates for TFR is vital, necessitating investigations into dislocation, infection, implant failure rates, local recurrence, overall survival, and associated factors.

Questions/purposes
(1) What is the postsurgical complication (hip dislocation and infection) rate and factors associated with postsurgical complications in patients who underwent TFR after tumor resection? (2) What is the local recurrence rate, implant failure rate, overall survival rate, and factors associated with local recurrence and implant failure?

Methods
We retrospectively evaluated 42 patients (median [range] age 47 years [10 to 79 years]) who underwent TFR and tumor resection at the time of the same surgical procedure between 1990 and 2020 at 12 registered institutions that specialized in tumor treatment in Japan. A total of 55% (23) of the patients were men, and 79% (33) had bone sarcoma. The median (range) follow-up period was 36.5 months (2 to 327 months). Of the 42 patients, 12% (5) were lost to follow-up before 2 years without meeting a study endpoint (postsurgical complications, revision, or amputation), and another 19% (8) died before 2 years with implants intact, leaving 69% (29) of the original group who had either follow-up of at least 2 years or met a study endpoint before the minimum surveillance duration. Another 10% (4) had a minimum of 2 years of follow-up but had not been seen in the past 5 years. Infection was defined as deep-seated infection involving soft tissues, bones, joints, and the area around the implant. We did not consider superficial infections. Implant failure was defined when a patient underwent reimplantation or amputation. The complication and implant failure rates were assessed by the cumulative incidence function method, considering competing events. The Kaplan-Meier method was used to estimate the overall survival rate.

Results
The 1-month, 6-month, 1-year, and 2-year dislocation rates were 5%, 12%, 14%, and 14%, respectively. The 1-month, 6-month, 1-year, and 2-year infection rates were 5%, 7%, 10%, and 15%, respectively. Multivariable analyses for hip dislocation and infection revealed that resection of the abductor muscles and large tumor size were positively associated with hip dislocation. The 6-month, 1-year, and 2-year local recurrence rates were 5%, 15%, and 15%, respectively. The 6-month, 1-year, 2-year, and 5-year implant failure rates were 5% (95% confidence interval 1% to 15%), 7% (95% CI 2% to 18%), 16% (95% CI 6% to 29%), and 16% (95% CI 6% to 29%), respectively. Multivariable analyses of local recurrence and implant failure that led to reimplantation or amputation revealed that a positive surgical margin was positively associated with local recurrence. The 1-year, 2-year, and 5-year overall patient survival rates were 95% (95% CI 87% to 102%), 77% (95% CI 64% to 91%), and 64% (95% CI 48% to 81%), respectively.

Conclusion
Hip dislocation, infection, and local recurrence were frequently observed in patients who received massive tumor resection and TFR in our study, eventually leading to reimplantation or amputation. Preserving the abductor muscles and resecting the tumor with a wide margin can prevent postoperative dislocation and local recurrence. Future research should focus on patient selection criteria, prevention of hip dislocation, and innovative treatments.

Level of Evidence
Level IV, therapeutic study.