Survival Rates and Patient-Reported Outcomes Support the Use of Custom Cement-Over Megaprosthesis (CCOM) in Complex Revision Lower Limb Arthroplasty.

Background: Patients presenting with periprosthetic osteolysis or fracture between ipsilateral hip and knee arthroplasties are challenging to treat successfully. Long-stem implants, osteopenic bones, and patient comorbidities all represent considerable surgical challenges. Poor results of fracture fixation in this group, coupled with the desire to retain well-performing implants and minimize soft-tissue trauma led to the developmentof the custom cement-over megaprostheses (CCOM). The aims of the study were to evaluate implant survivals, complications, and patient outcomes in those undergoing CCOM within our institution.

Methods: A retrospective analysis of patients undergoing CCOM between 2002 and 2022 was performed. We studied 34 cases, 33 patients, one patient underwent staged bilateral surgery with 26 women and 8 men.

Indications: trauma (16), failure of implants /aseptic loosening (9), or joint pathology. The mean Charlson comorbidity index was 3.5 (range, 0 to 8). All patients were followed up (mean 75 months [range, 9 to 170]) at 6 weeks, 6 months, 1 year, and annually thereafter. The VAS, EuroQol-5D-3L and MSTS scores were collected at 1 year.

Results: Implant survival defined by the primary outcome (all-cause revision of the implant at any time point) at 12 months of 97% (32 of 33). In surviving patients, implant survival was 90% (18 of 20) and all 7 survived at 5 and 10 years, respectively. Implant survival including those in the primary outcome group and those free of infection at 12 months was 84.8% (28 of 33) and in surviving patients, implant survival was 70% (14 of 20) and 7 out of 7 at 5 and 10 years, respectively.

Conclusions: The CCOM technique demonstrates good implant survivorships and satisfactory patient-reported outcomes in complex, often frail patients who have compromised bone stock. This series confirms the technique as an established alternative to total femoral replacement in these cases.