[Early clinical efficacy of metaphyseal metal sleeves for AORI type 2B/3 severe bone defect in revision total knee arthroplasty].

Objective: To investigate the early clinical efficacy and safety of metaphyseal metal sleeves in reconstructing Anderson Orthopedic Research Institute (AORI) type 2B/3 bone defects during revision total knee arthroplasty (rTKA). Methods: A retrospective analysis was performed on the 32 patients with severe metaphyseal bone defects who underwent rTKA and received metaphyseal reconstruction using a metal sleeve at West China Hospital, Sichuan University, from July 2018 to December 2023. All patients were followed-up regularly at 1, 3, 6, and 12 months postoperatively, and then annually thereafter. The knee joint range of motion (ROM) was recorded preoperatively, postoperatively, and at each follow-up visit. The pain was evaluated using the visual analogue scale (VAS), the knee function was assessed with the American Knee Society Score (KSS), and the clinical effectiveness was determined by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The integration quality of the sleeve-bone interface and prosthetic stability were evaluated by reviewing the full-length weight-bearing radiographs of both lower extremities as well as the anteroposterior and lateral radiographs of the knee joint obtained at the final follow-up. Compare the differences in indicators before the operation and at each follow-up. Results: In this cohort, there were 13 males and 19 females, with a mean age of (65.5±8.8) years; there were 18 cases of left-side and 14 cases of right-side revision. All the patients were followed-up for (36.8±7.7) months. All indicators were significantly improved from preoperative to final follow-up, with statistically significant differences (all P<0.05): the VAS score decreased from (4.8±2.3) points to (1.3±1.3) points; the knee joint ROM increased from 67.8°±14.1° to 98.8°±7.7°; the total KSS increased from (73.0±15.5) points to (177.6±8.2) points, among which the KSS functional score reached (88.0±5.5) points, significantly higher than the preoperative score of (30.5±15.2) points (P<0.001); the WOMAC score decreased from (64.1±20.6) points to (34.4±12.6) points. Radiological examinations confirmed that continuous osseointegration zones formed around the sleeves in 30 patients (93.75%), and all periprosthetic radiolucent lines were less than 2 mm. Postoperative complications included 1 case of incisional infection (cured by debridement) and 1 case of periprosthetic fracture (cured by internal fixation), with no revision cases reported. Conclusions: Metaphyseal metal sleeves, applied for the reconstruction of AORI type 2B/3 severe bone defects in rTKA, can achieve reliable biological fixation and mechanical support. The osseointegration rate reached 94% at short-term follow-up, with significant pain relief, remarkable improvements in joint function and range of motion observed in patients. Complications were manageable, and the short-term clinical efficacy was definite.