[Medium- to long-term outcomes of total hip arthroplasty for sequelae of hip infection]

Objective: To investigate the medium- to long-term outcomes of total hip arthroplasty (THA) for the treatment of sequelae of hip infection. Methods: A retrospective case series analysis was conducted on 94 patients who underwent primary THA for sequelae of hip infection at the Department of Orthopaedics, the First Affiliated Hospital of Xinjiang Medical University from January 2012 to January 2025. There were 43 males and 51 females, with an age of (43.5±14.5) years(range:18 to 77 years). The etiologies included 42 cases of sequelae of suppurative hip arthritis, 45 cases of sequelae of hip tuberculosis, and 7 cases of sequelae of hip osteomyelitis. The quiescent period of infection was (25.8±14.9) years (range:0.3 to 64.0 years). Based on pathoanatomical characteristics, patients were classified into three types: secondary osteoarthritis type (47 cases), dislocation type (21 cases), and ankylosis type (26 cases). Outcome measures included Harris hip score (HHS), complications, and prosthesis survival. Multivariable linear regression was used to identify factors influencing the improvement in HHS. Prosthesis survival was analyzed using the Kaplan-Meier method, and comparisons between groups were performed using the Log-rank test. Results: The follow-up duration was (68.3±42.1) months (range:0 to 160 months). The overall postoperative complication rate was 24.5% (23/94), including periprosthetic joint infection in 1 case (1.1%), aseptic loosening in 1 case (1.1%), prosthetic dislocation in 1 case (1.1%), and persistent hip pain in 2 cases (2.1%). Other complications included nerve injury in 3 cases (3.2%), acute liver injury in 3 cases (3.2%), and deep vein thrombosis in 9 cases (9.6%), all of which resolved with symptomatic treatment. At the final follow-up, the HHS increased from 42.1±10.9 preoperatively to 82.3±11.4 postoperatively (t=-29.492, P<0.01). Multivariable linear regression showed that pathoanatomical classification was independently associated with the degree of HHS improvement. Compared with the secondary osteoarthritis type, patients with the dislocation type (β=-7.900, 95%CI:-14.909 to -0.891, P=0.028) and the ankylosis type (β=-9.521, 95%CI:-15.540 to -3.502, P=0.002) had significantly less improvement in HHS after THA. Kaplan-Meier analysis revealed a prosthesis survival time of (153.1±3.4) months (95%CI: 146.4 to 159.7 months) and a 10-year survival rate of 94.7%. There was no significant difference in cumulative prosthesis survival among the dislocation type, ankylosis type, and secondary osteoarthritis type (P=0.078). Conclusions: Under the premise of a long quiescent period of infection, THA for sequelae of hip infection can achieve satisfactory medium- to long-term functional improvement and prosthesis survival. The pathoanatomical classification of the hip provides some guidance for assessing surgical difficulty and predicting postoperative outcomes.