MID-TERM CLINICAL AND RADIOLOGICAL OUTCOMES OF SHORT-STEM VERSUS CONVENTIONAL-STEM TOTAL HIP ARTHROPLASTY IN PATIENTS WITH OSTEONECROSIS OF THE FEMORAL HEAD: A PROSPECTIVE CASE-CONTROL STUDY.

BACKGROUND: Total hip arthroplasty (THA) in young patients with osteonecrosis of the femoral head (ONFH) poses unique challenges related to bone preservation and implant longevity. Short femoral stems have gained popularity due to their bone-conserving design, but limited evidence exists regarding their performance in ONFH. METHODS: A single-centre, prospective case-control study was conducted involving 108 patients undergoing primary cementless THA for ONFH. Twenty-seven patients received a metaphyseal-fitting short femoral stem (Exacta RS®), while 81 received a conventional length stem (Alteon® or Exacta®). All patients received the same uncemented acetabular cup (Jump System Traser®). Clinical outcomes were assessed using the Harris Hip Score (HHS) and Roles and Maudsley score. Radiographic evaluation included stem fixation (Moore signs), subsidence, radiolucency, and cup position. RESULTS: At a mean follow-up of 4.2 years, both groups demonstrated excellent clinical improvement. The postoperative HHS was 91±3.7 in the short stem group and 92±3.5 in the conventional stem group. Radiological assessments revealed complete osseointegration, with no evidence of periprosthetic osteolysis, femoral radiolucency, or cup loosening in either group. Minor, asymptomatic subsidence (2 mm) was observed in 2 short stem and 3 standard stem cases. There were no significant differences in complication rates, operative time, or length of hospital stay. CONCLUSION: Short femoral stems provide comparable mid-term clinical and radiographic outcomes to standard stems in young patients with ONFH. These findings support their use as a reliable, bone-preserving option in THA for this population. LEVEL OF EVIDENCE: Level III (Case-Control Study).