Radiological stability and functional performance of cementless modular long stems in revision hip arthroplasty: a minimum 4-year follow-up single-center experience

Revision total hip arthroplasty (rTHA) with substantial femoral bone loss is technically demanding, requiring durable distal fixation, biomechanical restoration, and early functional recovery. Cementless modular long stems provide diaphyseal fixation with intraoperative adjustability, yet mid-term evidence across diverse revision indications remains limited. This prospective single-center study evaluated radiological stability, functional outcomes, and modifiable prognostic factors, particularly early weight bearing.

Seventy-five patients underwent femoral rTHA with a cementless modular long-stem system between 2015 and 2020, achieving ≥ 4-year follow-up (mean 62 months). Indications included aseptic loosening (48%), periprosthetic fracture (29.3%), and two-stage reimplantation (16%); extended trochanteric osteotomy (ETO) was performed in 28%. Radiological evaluation assessed osseointegration, subsidence, and osteotomy union. Functional outcomes were measured using the Harris Hip Score (HHS), Oxford Hip Score (OHS), and EQ-VAS. Correlation and regression analyses examined relationships between bone defect grade, weight-bearing timing, and functional recovery.

Osseointegration was achieved in 94.6% of hips, with mean stem subsidence of 1.4 mm and complete ETO union. Functional scores improved significantly (HHS 44.2 → 87.6; OHS 22.3 → 40.5; EQ-VAS 54.6 → 82.1; all p < 0.001). Complications occurred in 9.2%, mainly superficial infection (5.3%) and dislocation (2.6%), with no aseptic loosening or modular junction failures. Earlier full weight bearing correlated with superior HHS (r = −0.47, p < 0.01). Four-year stem survival was 98.7%.

Cementless modular long stems provided reliable mid-term fixation, high osseointegration rates, and substantial functional improvement across varied revision indications. Low complication rates and absence of mechanical failures reinforce their utility in complex femoral revisions. Earlier achievement of full weight bearing was associated with superior functional outcomes.