Whilst Total Hip Arthroplasty (THA) remains a popular and reliable operation, the number of Hip Arthroscopy (HA) procedures performed has significantly increased in frequency over the past few years. Globally today, more patients are likely to undergo THA after previous HA (Conversion THA). The impact on post-operative clinical and functional outcomes remains controversial. We, therefore, aimed to compare the Patient-Reported Outcomes Measures (PROMs), satisfcation rates and complication rates after Conversion THA (>1 previous HA) with patients after Index THA (No previous HA).
We performed a retrospective case review of 898 consecutive patients for Primary THA by a high-volume surgeon with minimum 2-year follow-up using the Direct Anterior Approach. Demographic data and PROMs were recorded. All cases were assessed for complications and re-operations. Implant survival was calculated using Kaplan-Meier analysis. Statistical significance was p<0.05.
This study included 804 (89.53%) patients for Index THA (mean age 56.54years; BMI 28.54kg/m2) and 94 (10.47%) for Conversion THA (mean age 47.53years; BMI 29.91kg/m2), respectively. Satisfaction rates were similar for Index and Conversion THA patients (93.78% vs. 91.49%; p=0.009). The Patient Joint Perception (PJP) scores were “Native/Natural joint” for 68.78% of Index THA patients and 63.83% for Conversion THA patients (p=0.046). The mean pain score (p=0.003), modified Harris Hip Score (mHHS) (p=0.001) and Forgotten Joint Score-12 (p<0.000) favoured Index THA over Conversion THA patients. Conversion THA patients that had a single HA were 1.2-fold more likely to have a “Native/Natural joint” PJP compared to multiple HAs before THA (OR 1.42,1.18; p=0.008). Conversion THA patients that had a single HA are 2.01-fold more likely to have an mHHS =80 compared to multiple HAs (OR 3.3,1.64; p=0.018). Surgical complication rate was 7.45% for Index THA and 8.64% for Conversion THA (p=0.004). Deep PJI incidence for Index THA was 0.50% compared to 1.06% for Conversion THA (p=0.037). Total implant survival at 3 years was 97.9% (SE 0.005; 95%CI 96.9-98.9) for Index THA and 96.6% for Conversion THA (SE 0.019; 95%CI 92.9-1.00).
Medium-term PROMs are similar for Conversion THA and Index THA patients. However, Conversion THA following multiple HA’s show an increased risk for poor patient clinical outcomes compared to single HA.