Treatment of femoroacetabular impingement by arthroscopy versus anterior mini-open approach: Case-control study of a continuous series of 91 cases at a mean 4.6 years' follow-up

Abstract

Introduction: Femoroacetabular impingement is a frequent cause of hip pain, and can be managed by conservative surgery. Many studies assessed postoperative course, but none compared operative techniques within a given population. We therefore conducted a retrospective case-control study comparing the minimally invasive anterior Hueter approach versus arthroscopy, assessing difference in 1) functional gain and 2) complications and 3) analyzing the impact of labral or cartilage lesions on functional scores.

Hypothesis: Clinical results do not differ between the mini-open and arthroscopic approach.

Material and method: Between 2007 and 2018, 91 hips in 84 patients were treated for femoroacetabular impingement: 69/91 (75.8%) cam effect, 6/91 pincer effect (6.6%) and 16/91 mixed (17.6%). Fifty-five were treated by arthroscopy and 36 by the Hueter mini-open approach. There were 20 female and 71 male hips. Mean age at surgery was 32 years (range, 17-55 years). Potential predictive factors comprised Nötzli alpha angle, labral/cartilage lesion and type of surgery.

Results: Mean follow-up was 4.6 years (range, 1-16 years), with no loss to follow-up. The arthroscopy and Hueter groups showed no differences in functional improvement on Oxford-12 score (gain, -6.7±5.9 versus -6.2±8.1 (p=0.73), Postel Merle d'Aubigné (PMA) score (gain, 1.3±1 versus 1.1±0.9; p=0.41), operative time (75 versus 67min; p=0.16), or alpha angle correction (-10.9±12.9 versus -9.8±7.1; p=0.22). Complications did not differ: 1/55 severe complications after arthroscopy (1 definitive femoral nerve palsy) versus 4/36 non-severe complications after Hueter (3 cases of dysesthesia in the lateral cutaneous nerve of the thigh, 1 rectus femoris enthesopathy) (p=0.15). Labral lesions (37/91) did not affect clinical outcome: gain, 1.2±1 versus 1.3±0.9 on PMA (p=0.514) and -7.3±6 versus -6±7.3 on Oxford-12 (p=0.366). Cartilage lesions (27/91) were associated with poorer outcome on PMA (gain, 1±1.1 versus 1.3±0.9; p=002) but not on Oxford-12 (gain, -6.1±7.3 versus -6.7±6.6; p=0.288).

Conclusion: Impingement correction by the minimally invasive anterior Hueter approach gave clinical results comparable to those of hip arthroscopy in terms of Oxford and PMA scores, alpha angle correction, operative time and complications. Cartilage lesions were associated with poorer clinical results.

Level of evidence: III; retrospective case-control study.

Keywords: Anterior approach; Cam impingement; Femoroacetabular impingement syndrome; Hip arthroscopy; Mini-open Hueter approach; Pincer impingement.