To investigate the clinical efficacy of the screwcement technique for reconstructing noncontained posteromedial tibial plateau bone defects during total knee arthroplasty (TKA) in patients with Kashin-Beck disease (KBD).

This study included patients who underwent TKA between November 2018 and December 2023 and met the following criteria: diagnosis of KBD according to the Chinese diagnostic standard (WS/T 10026—2024), failure of conservative treatment, presence of non contained posteromedial tibial plateau defects with varus deformity, and no contraindications to surgery. Exclusion criteria: knee surgery or fracture histories, valgus or other extra-articular knee deformities, neurological disorders affecting function, and active infection. Patients were stratified by defect depth: those with defects ≤10 mm were assigned to the shallow defect group, and those with defects >10 mm to the deep defect group. All the patients underwent bone defect reconstruction using the screw cement technique. Preoperative and final follow-up data were recorded, including the Knee Society score (KSS), Western Ontario and McMaster Universities osteoarthritis index (WOMAC) score, range of motion (ROM), radiographic findings, and tibiofemoral angle (TFA). Prosthesis implantation and the number of screws used were also documented. Paired t tests were used for within group comparisons between preoperative and postoperative continuous variables, equivalence testing was applied for intergroup efficacy comparisons, and chi square test was used to compare the incidence of radiolucent lines.

A total of 48 patients (50 knees) were enrolled, including two patients with bilateral involvement. The shallow defect and deep defect groups each comprised 25 knees. The mean defect depths were (6.4±2.9) mm and (15.1±3.2) mm, respectively. There were no statistically significant differences in gender, age, or body mass index between the two groups (all P>0.05). The follow up duration was (49±11) months for the shallow defect group and (54±18) months for the deep defect group. Both groups showed significant improvements in KSS clinical (t=-37.516, -19.859) and functional scores (t=-110.667, -40.208) , WOMAC scores (t=19.105, 11.941) and ROM (t=-33.963, -15.531) after surgery (all P<0.001). At the final follow up, all prostheses were well fixed without loosening or migration. Radiolucent lines <two millimeters at the bone cement interface were observed in 23 cases (eight in the shallow defect group and 15 in the deep defect group), with no progressive widening during follow up and no cases of subsidence or osteolysis. TFA [(166.1±5.5)° vs (166.9±5.6)°] showed no statistically significant difference between groups before surgery (P>0.05). Compared with the data before surgery, TFA values were significantly improved in both groups after surgery (t=-8.229, -7.132, both P<0.001), with no statistically significant difference between two groups (P>0.05). Equivalence testing demonstrated that the postoperative clinical outcomes and correction of lower limb alignment were equivalent between the two groups.

The screw cement technique is a viable option for reconstructing non contained posteromedial tibial plateau defects in KBD patients undergoing TKA. It effectively restores knee biomechanical performance, provides reliable fixation in the short term, and is cost effective, making it particularly suitable for widespread application in the impoverished KBD affected population.