Recently, I attended The London Hip Meeting. Throughout the day there was a lot of discussion suggesting that Hip Resurfacing was a difficult surgery to learn and perform. I discussed this with my Managing Director, who set me the following task.
I am to convince him, by performing a quick literature comparison that Hip Resurfacing (HRA) is a more difficult procedure to learn when compared to Direct Anterior Approach Total Hip replacement (DAA THA).
As you know I am no researcher, so what follows are my unbiased findings...so far!
Recently, Peters et al (2022) identified a 64% risk of revision for patients undergoing THA using DAA for the first 50 cases per surgeon¹, the results were taken from 15,875 procedures performed between 2007 and 2019. From 100 cases onwards, the study found a steady state had been reached relative to revision rate¹. This set of data allowed the authors to establish an estimated learning curve for DAA THA to be around 100 cases.
An earlier study by Kong et al, (2019) stated DAA is a “technically demanding procedure” associated with a high complication rate early in the learning curve. Their experience reported a decrease in the complication rate from 44% in the first 50 cases to 16% in the second 50². The results led the authors to estimate surgeons need to complete 88 cases before complication rates normalize, and 72 cases before surgical times normalize. This work is supported by Nairm et al (2021) who found complication rates decreased substantially from early to late groups³. The assessment compared twenty-one studies in a systematic review which consisted of 9,738 patients and demonstrated a substantial learning curve associated with DAA.
From the range of articles I’ve read, DAA THA is perceived to be technically challenging, and transitioning surgeons may experience a considerable increase in complication rates with an average learning curve of around 100 cases. Some authors such as De Steiger reported that 400 cases are required “to achieve a surgical time similar to a posterior lateral approach in surgeons adopting the DAA”⁷.
So, onto Hip Resurfacing...
“Learning from the learning curve in total hip resurfacing: a radiographic analysis” suggests the learning curve of the first 40 total hip resurfacings to be acceptable⁴. Although this was a single-person study, the result was not too different from Van Der Straeten, and De Smet (2014) who reported the consensus of an international faculty of expert (MoM) hip surgeons with a combined experience of over 40,000 cases. While it is acknowledged HRA is “technically demanding”, the results from the consensus concluded 50 hip resurfacing procedures were necessary to get past the learning curve⁵; half as many as the average suggested for DAA.
Nunley et al (2010) published an article that reported a learning curve for achieving the desired component positioning radiographically was much longer at 75 to 100 cases⁶.
These results lead me to believe both procedures are equally challenging, but importantly both can be learned in a similar amount of time. I guess the current frequency of Hip Resurfacing serves as a rate limiter, However, I do not understand why Hip Resurfacing is frequently reported as more difficult to learn... Let me know your thoughts!
1. Peters, RM et al. “The direct anterior approach learning curve is 100 cases: an analysis based on 15,875 total hip arthroplasties in the Dutch Arthroplasty Register.” Acta orthopaedica vol. 93 775-782. 27 Sep. 2022, doi:10.2340/17453674.2022.4802
2. Kong, Xiangpeng, et al. “Adopting the direct anterior approach: experience and learning curve in a Chinese patient population.” Journal of orthopedic surgery and Research vol. 14,1 218. 16 Jul. 2019, doi:10.1186/s13018-019-1272-0
3. Nairn, Leah, et al. “The learning curve for the direct anterior total hip arthroplasty: a systematic review.” International orthopaedics vol. 45,8 (2021): 1971-1982. doi:10.1007/s00264-021-04986-7
4. Witjes, Suzanne et al. “Learning from the learning curve in total hip resurfacing: a radiographic analysis.” Archives of orthopaedic and trauma surgery vol. 129,10 (2009): 1293-9. doi:10.1007/s00402-009-0875-z
5. Van Der Straeten, Catherine, and Koen A De Smet. “Current expert views on metal-on-metal hip resurfacing arthroplasty. Consensus of the 6th advanced Hip resurfacing course, Ghent, Belgium, May 2014.” Hip International: the journal of Clinical and experimental research on hip pathology and Therapy vol. 26,1 (2016): 1-7. doi:10.5301/hipint.5000288
6. Nunley, Ryan M et al. “The learning curve for adopting hip resurfacing among hip specialists.” Clinical orthopedics and related research vol. 468,2 (2010): 382-91. doi:10.1007/s11999-009-1106-1
7. Noel d SR, Michelle L, Michael S. What is the learning curve for the anterior approach for total hip arthroplasty? Clin Orthop Relat Res. 2015;473:3860–3866. doi: 10.1007/s11999-015-4565-6.
Hip Resurfacing Surgical Technique