Management of sarcoma recurrence after megaprosthesis of the knee

The Patient Acceptable Symptom State (PASS) after proximal and distal femoral replacement

INTRODUCTION

Femoral megaprostheses are used for bone reconstruction surgery in patients with local tumors or who require multiple revisions. Patient reported outcome measures (PROMs) provide a subjective result and, like patient satisfaction, have become an integral part of the outcomes in orthopedics. However, the threshold of satisfaction (PASS: Patient Acceptable Symptom State) has not yet been defined in a French population after this type of arthroplasty. This led us to carry out a retrospective study on a population of patients who received a femoral reconstruction megaprosthesis in order to 1) define the PASS for the Harris Hip Score (HHS), Knee Society Score (KSS) and the Musculoskeletal Tumor Society score (MSTS), 2) study the complications.

HYPOTHESIS

The PASS threshold for proximal femur and distal femur reconstruction prothesis for the HHS and the KSS, respectively, will be lower than the threshold for these same scores for primary arthroplasty.

MATERIALS AND METHODS

Forty-four patients who were operated on between 2009 and 2020 were included: 23 received a proximal femur prosthesis and 21 received a distal femur prosthesis. The PASS threshold was defined using an anchoring strategy by analyzing ROC curves for the HSS for the proximal femur, KSS for the distal femur and the MSTS for all the prostheses. Complications were classified according to Henderson.

RESULTS

The mean follow-up was 4.5 ± 3.6 (1-12.5) years. The PASS threshold was 47.5 (area under curve (AUC) 0.71 (0.45-0.97)) for the HHS, 69.5 (AUC 0.97 (0.92-1.0)) for the KSS knee and 62.5 (AUC 0.81 (0.61-0.99)) for the KSS function. Thirteen patients (29%) had complications, nine of whom required another surgery (20%). The most frequent were Henderson type 1 (soft tissue lesions, n = 5/44 [11%]) and type 2 (loosening, n = 5/44 [11%]) There was no relationship between satisfaction and postoperative complications (p = 0.071).

DISCUSSION

Most of the patients who undergo femoral resection and reconstruction (59%) are satisfied with their function, albeit reduced, despite a high complication rate (29%). Our hypothesis is confirmed for the PASS threshold for the HHS (47.5 versus 93) and the KSS knee and function (69.5 and 62.5 versus 85.5 and 72.5).

LEVEL OF EVIDENCE

IV; retrospective observational single-center study.

Induced-membrane technique for lower limb reconstruction after malignant bone tumour resection in paediatric patients: Complication and re-operation rates

BACKGROUND

The objective of this study was to assess the complication and re-operation rates, evaluate the risk of non-union, and describe the functional outcomes at last follow-up in children and adolescents after lower-limb malignant tumour resection and reconstruction using the induced-membrane technique.

HYPOTHESIS

Weight-bearing resumption 6 weeks after the second stage of the induced-membrane procedure promotes bone healing.

MATERIAL AND METHODS

The study included 13 patients (9 with osteosarcoma, 3 with Ewing's sarcomas, and 1 with alveolar sarcoma) managed between 2000 and 2020 by oncological femoral or tibial resection followed, at a distance from adjuvant chemotherapy, by reconstruction using the induced-membrane technique. Non-union was the primary outcome measure and the MusculoSkeletal Tumor Society (MSTS) lower-limb functional score was the secondary outcome measure. Mean follow-up was 6.1 years (range, 2.0-12.7). At last follow-up, mean age was 18.1 years (range, 11.0-26.0) and the mean MSTS score was 66.6% (37.0-93.0%).

RESULTS

After the second reconstruction stage, 8 complications developed in 6 patients (46%). Either a complication or limb-length inequality required 12 re-operations in 8 patients (61.5%). Non-union occurred after reconstruction in 5 (38.5%) patients. Early resumption of 50% weight-bearing 6 weeks after reconstruction was associated with bone healing (p=0.02).

CONCLUSION

The non-union rate was 38.5%. Partial, 50% weight-bearing with two elbow crutches and an orthosis, if allowed by construct stability, may promote bone healing.

LEVEL OF EVIDENCE

IV.

What to improve: Results of fixed-hinge knee endoprosthesis reconstructions over 40 years in a single tumor center

INTRODUCTION

Over the past decades, numerous structural changes in implants, medical treatments, and surgical techniques have been made for Malignant Bone Tumors (MBT) around the knee. However, the overall care improvement is still unclear. The method is crucial when analyzing outcomes in surveys involving tumors, and a thorough assessment of the mortality is mandatory because death acts as competing event. The aims of this study were: 1) a comprehensive and longitudinal assessment of the revisions with an extensive follow-up and adequate methods; 2) a complete mortality review to consider competing risks.

HYPOTHESIS

The hypothesis was that some prosthesis's structural improvements were made while the surgical toll increased as well as an improvement of mortality was also expected.

MATERIAL AND METHODS

Analyses were performed on 248 patients with MBT (mean follow-up was 8.7 years, surgeries between 1972 and 2017). Three prosthesis models were successively used over time: 120 Guepar (older model), 42 Tornier, and 86 Stanmore (more recent model). The primary outcome was the assessment of revisions sorted out according to Henderson: type-1 soft-tissue failures or instability, type-2 aseptic loosening, type-3 structural failures, type-4 periprosthetic infections, type-5 tumoral progression. Death and amputations were considered as competing events. An extensive assessment of mortality was performed by merging the dataset with the French register of Deaths (INSEE). Cumulative probabilities were computed at 2, 5, 10, and 15 years and compared with Gray's tests.

RESULTS

The overall 5-year survival was, 80% (95% CI: 73-87) for Guepar, 69% (95% CI: 56-84) for Tornier, and 71% (95% CI: 62-82) for Stanmore (p=0.4). The 5-year cumulative risks for type-1 were 5% (95% CI: 1-9), 9% (95% CI: 0-18), and 17% (95% CI: 9-25) for Guepar, Tornier, and Stanmore, respectively (p=0.01). The 15-year cumulative risks for type-2 were 22% (95% CI: 15-39), 8% (95% CI: 0-17) and 8% (95% CI: 2-14) for Guepar, Tornier, and Stanmore, respectively (p=0.10). Ten patients had an implant failure, nine Guepar, and one Tornier. The 5-year cumulative risks for type-4 were 7% (95% CI: 2-12), 19% (95% CI: 7-31), and 12% (95% CI: 5-18) for Guepar, Tornier, and Stanmore, respectively (p=0.08). There were 29 tumoral progressions; the 15-year risks were 16% (95% CI: 2-22), 2% (95% CI: 0-7%), and 12% (95% CI: 4-19%) for Guepar, Tornier, and Stanmore, respectively (p=0.08). No difference whatsoever was found between the proximal tibial and distal femur.

CONCLUSION

There were some improvements in prosthesis design (forged steel instead of cast steel) and probably also in cemented stem fixation, but not in prosthetic joint infection and local recurrence over forty years. The overall mortality did not change significantly over the last 40 years amongst this specific cohort of patients who benefited from a hinge reconstruction prosthesis.

LEVEL OF EVIDENCE

III; comparative case series with sensibility analysis.