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

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.

The clinical outcome of chondrolabral-preserving arthroscopic acetabuloplasty for pincer- or mixed-type femoroacetabular impingement: A systematic review

While preservation and repair of the acetabular labrum are increasingly being recognized as important goals in hip arthroscopy, controversies still exist regarding the clinical outcome of arthroscopic acetabuloplasty with chondrolabral preservation. A systematic review was conducted and implemented by two independent reviewers, who used the MEDLINE/PubMed database and the Cochrane Database of Systematic Reviews for their search. These databases were queried with the terms "arthroscopic acetabuloplasty" and "chondrolabral preservation" and "arthroscopic acetabular recession." From the 55 initial studies the reviewers finally chose and assessed five clinical studies which were eligible to their inclusion-exclusion criteria. The reviewed studies included in total 444 patients, mainly young, between 30 and 40 years old. The follow-up evaluation varied between 24 and 41 months, while all studies utilized at least a 24-month final end-point assessment. All five studies illustrated improved outcome with the use of chondrolabral preservation acetabuloplasty without labral detachment. The rate of complications was very low. The different techniques of arthroscopic acetabuloplasty combined with chondrolabral preservation illustrated encouraging results in patients suffering from pincer-type or mixed-type FAI. However, the available clinical evidence was limited and insufficient to establish any superiority of these techniques over the traditional labral detachment and sequential reattachment. In relation to the optimal treatment of FAI without isolated CAM, further research of higher quality is recommended to be conducted in order to lead to definitive conclusions.

Size and shape of the lunate surface in different types of pincer impingement: theoretical implications for surgical therapy

OBJECTIVE

Acetabular rim trimming is indicated in pincer hips with an oversized lunate surface but could result in a critically decreased size of the lunate surface in pincer hips with acetabular malorientation. There is a lack of detailed three-dimensional anatomy of lunate surface in pincer hips. Therefore, we questioned how does (1) size and (2) shape of the lunate surface differ among hips with different types of pincer impingement?

METHOD

We retrospectively compared size and shape of the lunate surface between acetabular retroversion (48 hips), deep acetabulum (34 hips), protrusio acetabuli (seven hips), normal acetabuli (30 hips), and hip dysplasia (45 hips). Using magnetic resonance imaging (MRI) arthrography with radial slices we measured size in percentage of the femoral head coverage and shape using the outer (inner) center-edge angles and width of lunate surface.

RESULTS

Hips with retroversion had a decreased size and deep hips had normal size of the lunate surface. Both had a normal shape of the outer acetabular rim. Protrusio hips had an increased size and a prominent outer acetabular rim. In all three types of pincer hips the acetabular fossa was increased.

CONCLUSION

Size and shape of the lunate surface differs substantially among different types of pincer impingement. In contrast to hips with protrusio acetabuli, retroverted and deep hips do not have an increased size of the lunate surface. Acetabular rim trimming in retroverted and deep hips should be performed with caution. Based on our results, acetabular reorientation would theoretically be the treatment of choice in retroverted hips.

Pincer deformity does not lead to osteoarthritis of the hip whereas acetabular dysplasia does: acetabular coverage and development of osteoarthritis in a nationwide prospective cohort study (CHECK)

OBJECTIVE

Determining the relation between acetabular coverage, especially overcoverage which may lead to pincer impingement, and development of osteoarthritis (OA) of the hip.

DESIGN

From a prospective cohort study of 1,002 individuals with symptoms of early OA (Cohort Hip and Cohort Knee, CHECK), 720 participants were included. Standardized anteroposterior pelvic radiographs and false profile lateral radiographs were obtained at baseline and 5 years follow-up. Acetabular undercoverage (mild dysplasia) and overcoverage (pincer deformity) were measured by a centre edge angle of <25° and >40° respectively in both radiographic views. The strength of association between those parameters at baseline and development of incident OA (Kellgren and Lawrence (K&L) grade >2 or total hip replacement), or joint space narrowing within 5 years was expressed in odds ratio (OR) adjusted for K&L grade, age, body mass index (BMI), and sex using generalized estimating equations.

RESULTS

At baseline, 76% of the included hips had no signs of radiographic OA (K&L = 0) whereas 24% had doubtful OA (K&L = 1). Within 5 years, 7.0% developed incident OA. Acetabular dysplasia was significantly associated with development of incident OA with ORs between 2.62 (95% confidence interval (CI) 1.44-4.77) and 5.45 (95% CI 2.40-12.34), dependent on the radiographic view. A pincer deformity was not associated with any outcome measure, except for a significantly protective effect on incident OA when a pincer deformity was present in both radiographic views OR 0.34 (95% CI 0.13-0.87).

CONCLUSION

Acetabular dysplasia was significantly associated with development of OA. However, a pincer deformity was not associated with OA, and might even have a protective effect on its development, which questions the supposed detrimental effect of pincer impingement.

Femoro-acetabular impingement: the diagnosis-a review

BACKGROUND

The recognition of the importance of femoral acetabular impingement (FAI) as a potential cause of hip pain has been stimulated by major efforts to salvage hip joints by reconstruction in order to prevent or delay the need for replacement. The purpose of this review is to define the nature of FAI, the various types, and how to make the diagnosis.

METHODS

The review describes the characteristics of the hip that cause FAI and emphasizes understanding that the femoral and acetabular components normally function as a unit, complementing each other.

RESULTS/CONCLUSION

The methods of making the diagnosis of FAI and their limitations are described. If the acetabulum and femur are considered to be independent of each other, conflict may occur, hindering function, and not be apparent. The increasing frequency of making this diagnosis based on abnormal anatomy on one side of the joint, often in face of unclear physical findings, can bring the diagnosis into question. FAI seen in Perthes disease and acetabular dysplasia is explained. Knowing how to analyze the hip, being aware of the limitations of various available clinical and diagnostic studies, and recognizing the continued and ever-changing extensive body of literature is important and challenging. This primer is just the beginning.