Revision for adverse local tissue reaction following metal-on-polyethylene total hip arthroplasty is associated with a high risk of early major complications

This is the author accepted manuscript. The final version is available from the British Editorial Society of Bone and Joint Surgery via the DOI in this record. Aims Fretting and corrosion at the modular head/neck junction, known as trunnionosis, in total hip arthroplasty (THA) is a cause of adverse reaction to metal debris (ARMD). We describe the outcome of revision of metal-on-polyethylene (MoP) THA for ARMD due to trunnionosis with emphasis on the risk of major complications. Patients and Methods A total of 36 patients with a MoP THA who underwent revision for ARMD due to trunnionosis were identified. Three were excluded as their revision had been to another metal head. The remaining 33 were revised to a ceramic head with a titanium sleeve. We describe the presentation, revision findings, and risk of complications in these patients. Results The patients presented with pain, swelling, stiffness, or instability and an inflammatory mass was confirmed radiologically. Macroscopic material deposition on the trunnion was seen in all patients, associated with ARMD. Following revision, six (18.2%) dislocated, requiring further revision in four. Three (9.1%) developed a deep infection and six (18.2%) had significant persistent pain without an obvious cause. One developed a femoral artery thrombosis after excision of an iliofemoral pseudotumor, requiring a thrombectomy. Conclusion The risk of serious complications following revision MoP THA for ARMD associated with trunnionosis is high. In the presence of extensive tissue damage, a constrained liner or dual mobility construct is recommended in these patients

Outcome of kinematic alignment using patient-specific instrumentation versus mechanical alignment in TKA: a meta-analysis and subgroup analysis of randomised trials

This is the author accepted manuscript. The final version is available from Springer via the DOI in this record. Introduction Kinematic alignment (KA) in total knee arthroplasty (TKA) matches component position to the pre-arthritic anatomy of an individual patient, with the aim of improving functional outcomes. Recent randomised controlled trials (RCTs) comparing KA to traditional neutral mechanical alignment (MA) have been mixed. This collaborative study combined raw data from RCTs, aiming to compare functional outcomes between KA using patient-specific instrumentation (PSI) and MA, and whether any patient subgroups may benefit more from KA technique. Materials and methods A literature search in PubMed, EMBASE and Cochrane databases identified four randomised controlled trials comparing patients undergoing TKA using PSI-KA and MA. Unpublished data including Western Ontario McMaster Universities Arthritis Index (WOMAC) and Knee Society Score (KSS) were obtained from study authors. Metaanalysis compared MA to KA change (post-op minus pre-op) scores. Subgroup-analysis on KA patients looked for subgroups more likely to benefit from KA and the impact of PSI accuracy. Results Meta-analyses of change scores in 229 KA patients versus 229 MA patients were no different from WOMAC (mean difference 3.4; 95% confidence interval − 0.5 to 7.3), KSS function (1.3, − 3.9 to 6.4) or KSS combined (7.2, − 0.8 to 15.2). A small advantage was seen for KSS pain in the KA group (3.6, 95% CI 0.2–7.1). Subgroup-analysis showed no difference between varus, valgus and neutral pre-operative alignment groups, and those who did and did not achieve KA plans. Painfree patients at 1-year were more likely to achieve KA plans. Conclusion Patient-reported outcome scores following TKA using PSI-KA are similar to MA. No identifiable subgroups benefited more from KA, and long-term results remain unknown. Inaccuracy of the PSI system used in KA patients could potentially affect outcome