A prospective randomised clinical trial in total hip arthroplasty - comparing early results between the direct anterior approach and the posterior approach

2017-03-02T23:20:24Z (GMT) by Cheng, Tze Ern
Early functional outcomes following direct anterior approach (DAA) total hip arthroplasty (THA) when compared with other approaches remains a contentious subject. This study aims to compare early clinical, functional and radiological outcomes in patients randomised between the DAA and posterior approach (PA) for THA. Between March 2014 and March 2015, 73 participants (35 DAA, 38 PA) received THA surgery at Eastern Health. Participants were evaluated pre-operatively, 2 weeks, 6 weeks and 3 months post operatively following THA surgery with multimodal outcome measures. The primary outcome measure was the Western Ontario McMasters Arthritis Index (WOMAC). Secondary measures included the Oxford Hip Score, EQ-5D, 10 metre walk test, radiological and clinical parameters. Clinical parameters analysed were length of stay, surgical time, opiate analgesic requirements, post-operative haemoglobin levels, complications, hip function and range of movement. The primary end point was time, 3 month post operatively. Statistical analysis was performed using liner mixed models and Wilcoxon Rank Sum Tests. The DAA group had longer operative times, smaller surgical wounds and higher blood loss. The length of acute hospital stay was significantly shorter for the DAA group with surgeon 1 but not for surgeon 2 or the combined results. There was no difference in total length of hospital stay between both groups. The DAA group also had a lower post-operative opiate analgesic usage 2 weeks after THA surgery. The DAA group additionally had better hip bending function 2 weeks and 6 weeks post-operatively. The DAA group had significantly weaker straight leg raise function at 2 weeks and 6 weeks post-operative time points compared to the PA group. The incidence of lateral cutaneous nerve of thigh (LCNT) neuropraxia was 83% in the DAA group. Excluding LCNT neuropraxia the other complications were not statistically significant between both groups. The study concludes that DAA THA has comparable results with PA THA. Results obtained support current evidence in the literature for both early outcomes and complications. Outcomes following DAA THA can vary between surgeons. DAA THA has benefits in improved hip bending in the early post-operative period in the absence of hip precautions. This comes at a price of weaker straight leg raise function.