Purpose:
Clinical outcomes following surgical revision in cases of histologically confirmed arthrofibrosis after total hip arthroplasty (THA) have not been published to date. Consequently, the aim of this study is to present the clinical outcomes and to identify risk factors for poor clinical outcome following surgical intervention for histologically verified endoprosthesis-associated arthrofibrosis of the hip after THA.
Methods:
This study enrolled 7983 THA revision procedures during the study period, in 51 cases arthrofibrosis has been histologically confirmed based on the synovial-like interface membrane (SLIM) criteria. For the final statistical analysis 42 cases (59.5 % women) with an average age of 63.6 years were included, achieving a follow-up rate of 82.6 % with a mean follow up of 70 months. Of these, 73.8% underwent index surgery after primary THA implantation. The primary indication for revision surgery was predominantly the clinical suspicion of arthrofibrosis (n = 35). In addition to the complication and revision rates, the Harris Hip Score (HHS) and the EQ-5D-3L questionnaire were analysed for all cases at the time of follow-up.
For the risk analysis of a poor clinical outcome (HHS <55), the study cohort was divided into two different groups.
Results:
Open arthrolysis was performed in all cases (100 %), with a mobile component being replaced in 73.8 % of cases (n = 31) and only two cases requiring additional replacement of the femoral and acetabular components due to aseptic loosening.
The Harris Hip Score (HHS) had a mean value of 53.2 before revision surgery and increased significantly postoperatively to a mean value of 65.7 (p < 0.001). It is noteworthy that only 34.1 % of patients achieved the minimum clinical significance difference (MCID) of 18 HHS points after surgical revision. The EQ-5D Visual Analogue Scale (VAS) score and the Time Trade-Off (TTO) score averaged 0.226 (SD 0.245) and 0.221 (SD 0.37).
Complications occurred in seven cases (16.7 %,), with dislocation in 2 cases and persistent AF symptoms in 3 cases being the most common, accompanied by a revision rate of 14.3 % (n = 6). In three cases, a new open arthrolysis was performed due to persistent symptoms. Increased BMI (30.1 vs. 26.7 BMI, p < 0.05) or higher body weight (88.4kg vs. 78.7kg, p = 0.086) and a lower preoperative HHS (p = 0.022) were identified as risk factors for a poor clinical outcome, defined as HHS < 55.
Conclusion:
The initial clinical results following surgical intervention for endoprosthesis-associated arthrofibrosis show a moderate to poor postoperative outcome with an acceptable complication rate. The type of surgical intervention does not appear to have any influence on a poor clinical outcome.