The overall results, measuring the complication rate, revision rate and patient-reported outcome, were in favor of the peripheral-compartment-first technique. Those results are in accordance with previously published studies [9, 10, 19]. In our patient cohort with a mean follow-up period of 6.2 ± 2.1 years, about 3.7% of patients converted to THA, only 2.6% of patients underwent revision hip arthroscopy, and as little as 0.28% of patients experienced a serious complication requiring fixation of the femoral neck. As little as 9.8% of the patients would not have this procedure performed again retrospectively.

In comparison with the results from a recent meta-analysis of 31 clinical studies, including a total of 1981 hips, the complication rate (0.28% vs. 1.7% [2]) was lower in this study. Moreover, conversion to total hip arthroplasty was less common in our series [26/704 hips (3.7%) vs. 128/1981 hips (6.5%)], although the mean follow-up period was substantially longer (6.2 ± 2.1 years vs. 29.5 ± 13.9 months). An even more recent systematic review reported an average conversion to THA rate of 11.1% (range 3.0 to 17.9%) and a secondary hip preservation surgery rate of 8.9% (range 0.0 to 17.4%) in seven 5-year follow-up studies including a total of 873 hips [3]. Again, both reported rates are substantially higher than those found in our series. A detailed comparison of patient-reported outcome measures with recently published studies on hip arthroscopy starting in the central compartment was slightly in favor of the peripheral-first approach and is summed up in Table 2 [20,21,22].

Overall, our results are in accordance with previously published outcome studies of the peripheral-compartment-first technique by other authors, as shown by a single peripheral-compartment-first cohort of 154 patients who were followed up for 2 years [19], a single cohort of 72 hips followed up for 5 years [8], and a non-randomized controlled cohort study of 30 hips that underwent the peripheral-compartment-first technique and 30 hips that underwent the central-compartment-first technique [9]. All of the above-cited studies advocate the use of the peripheral-compartment-first technique, mainly because of a reduced complication rate associated with this technique.

The reason for the reduced complication rate remains unclear. However, hip arthroscopy is a complex surgical procedure with a significant learning curve. Iatrogenic damage to the labrum and cartilage is a common complication. In contrast to arthroscopy of the knee, shoulder, elbow, or ankle, palpation cannot be used to guide portal placement in this procedure, owing to the deep location of this joint. Portal placement may be the most dangerous step in hip arthroscopy in terms of iatrogenic labrum or cartilage damage, and direct visualization of portal placement seems a viable way to prevent damage; however, this has never been demonstrated in the literature. Another benefit of the peripheral-compartment-first technique with separate portals for intra-articular and peripheral arthroscopy might be the lack of large capsulotomies. The literature has shown significant concerns with unrepaired capsulotomies [23], and it may be assumed that small stabbing incisions are superior to large capsulotomies, even if repaired. However, well-designed comparative studies are needed to clarify the clinical significance of these theoretical advantages of the peripheral-compartment-first technique. The peripheral-compartment-first technique is simple and reproducible, and our clinical results are in accordance with previous literature. The peripheral-compartment-first approach is most popular in Europe, in specialized departments with a relatively high number of cases. Data on time efficacy show that the set-up time and procedure time of this technique are very similar to those of standard hip arthroscopy. The set-up in the peripheral-compartment-first technique required 5 min more than the traditional technique (38 min vs. 33 min) [24], and the surgery required only 3 min more (116 min vs. 119 min) than the traditional technique [24]. Overall, there was no seemingly relevant time difference between the two techniques.

Our cohort study, with a large sample size for this surgical technique and a midterm follow-up period of 6 years, adds to the existing literature. The major limitations of this study include a relatively small return rate for the patient-reported outcomes of 60.2%, the lack of a control group to compare this method with hip arthroscopy starting in the central compartment, and the lack of baseline patient-reported outcome assessment before surgery.