Recovery of leg strength based on isokinetic testing after tumor resection and reconstruction with a modular rotating hinge knee system: Prospective cross-sectional study with a minimum follow-up of 24 months

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.

Distal femoral megaprosthesis fracture treated by RescueSleeve MEGASYSTEM-C

Escalating revision surgery after megaprosthesis knee replacement sometimes raises the question of "limb salvage". Here we present a salvage technique for megaprosthesis fracture at the junction between the stem and the metaphyseal component. In this young active patient, the short residual proximal femur was not loose and was difficult to extract without prosthetic escalation. The technique described here conserved the well-fixed primary stem and used a custom-made RescueSleeve MEGASYSTEM-C connection sleeve (Link, Hamburg, Germany) plus spacer and a standard epiphyseal implant. This semi-conservative procedure avoided femorotomy or larger morbid segmental femoral resection. It conserved maximal bone stock and achieved rapid functional recovery. To our knowledge, this is the first reported case of this technique using a custom-made connecting part to manage megaprosthesis fracture. LEVEL OF EVIDENCE: IV.