VOL. 95-B, No. 10, OCTOBER 2013 1297

EDITORIAL

Femoroacetabular impingementNOT JUST A SQUARE PEG IN A ROUND HOLE

F. S. Haddad,S. Konan

From The British Editorial Society of Bone & Joint Surgery, London, United Kingdom

F. S. Haddad, MD(Res), MCh(Orth), FRCS(Orth), Editor-in-ChiefThe Bone & Joint Journal, 22 Buckingham Street, London WC2N 6ET, UK.

S. Konan, MBBS, MD(res), MRCS, FRCS(Tr&Orth), Specialist Trainee, NE(UCH) Thames Rotation, LondonUniversity College London Hospitals, 235 Euston Road, London, NW1 2BU, UK.

Correspondence should be sent to Professor F. S. Haddad;e-mail: editorbjj@boneandjoint.org.uk

©2013 The British Editorial Society of Bone & Joint Surgerydoi:10.1302/0301-620X.95B10. 33025 $2.00

Bone Joint J 2013;95-B:1297–8.

Evidence surrounding the pathomechanical pro-cess that underpins femoroacetabular impinge-ment (FAI) continues to emerge. FAI, as weunderstand today, is a wide spectrum of mechan-ical variations of the femoral head and/or the ace-tabulum that manifests at extremes of hip motionoften associated with sporting activities. Chon-dral and labral damage that follows fromrepeated asymmetrical motion of the ball andsocket appears to predispose to later osteoarthri-tis. This issue of The Bone & Joint Journal fea-tures a paper1 that demonstrates the differencesin the location and mode of labral tears betweendysplastic hips and those with femoroacetabularimpingement and identifies some tears morelikely to be linked to adjacent acetabular cartilagedamage. It highlights some of the deficiencies inour understanding and stresses the importance ofa global understanding of the hip and of hippathoanatomy and not just of hip arthroscopy.

So let it be written…The concept of FAI was recognised more than a cen-tury ago. However, FAI in its current avataremerged around the 1990s. The world literature hasseen an exponential surge in the number of pub-lished articles on this topic. A quick scan of the Pub-Med reveals that there was one article publishedbefore 2000 and that nearly 60% of all articles onthe subject have been published since 2011. Theconcern however, is the paucity of Level I evidence.While dysplasia in the orthodox form has kept thehip surgeon intrigued since time immemorial,understanding FAI may be the harbinger of therenaissance necessary to change our outlooktowards the hip joint. While increasing literature isoften synonymous with better understanding, wehave seen an increased number of submissions withsmall cohorts, some with new unproven hiparthroscopy techniques with very short follow-upand very little basic translational data or in the wayof prospective comparative studies. The pathology,presentation, clinical features, diagnosis and man-agement of FAI are still not completely understood,and provide a wealth of opportunity for the ortho-paedic community. The Bone & Joint Journal iskeen to embrace this area but will place greatemphasis on originality of hypotheses, level of evi-dence, longevity of follow-up and validity of out-come measures.

The tip of the icebergIt is clear of course that some of our understand-ing of FAI has evolved. We have published gooddata that confirm the causal link between FAI

and osteoarthritis and the safety and efficacy ofsurgery in alleviating symptoms and improvinghip function in the early to mid-term follow-up.2

Hominid evolution may offer an explanation forthe variants in hip morphology associated withimpingement. The evolutionary conflict betweenupright gait and the birth of a large-brainedfetus is expressed in the female pelvis and hip,and can explain pincer impingement in a coxaprofunda. In the male hip, evolution mayexplain cam impingement in coxa recta as anadaptation for running.3

We have some understanding of the aetiologyof FAI. The persistent deformity with radiologi-cal cam FAI after slipped upper femoral epiphy-sis (SUFE) is associated with poorer clinical andradiological long-term outcome.4

However, it also appears that the cam-typefemoroacetabular deformity is not rare in theasymptomatic population. FAI appears to betwice as frequent in men as in women. Althoughan association between osteoarthritis and FAI isbelieved to exist, a long-term epidemiologicalstudy is needed to determine the natural historyof these anatomical abnormalities.5

We have observed that a substantial propor-tion of hips with FAI may not develop osteoar-thritis in the long-term. Accordingly, in theabsence of symptoms, prophylactic surgicaltreatment is not warranted.6

We now have a simple reproducible classifica-tion system for lesions of the acetabular carti-lage, which it is hoped will allow standardiseddocumentation to be made of damage to thearticular cartilage, particularly that associatedwith FAI.7

We have observed the benefit of arthroscopyof the hip in the treatment of FAI in terms ofquality of life (QoL). One year after surgery theQoL scores improve in approximately 76.6%,remained unchanged in 14.4% and deterioratein 9.0%.8

Our published studies show that patientswithout advanced degenerative changes in thehip can achieve significant improvement in theirsymptoms after arthroscopic treatment of FAI.Where appropriate, labral repair provides asuperior result to labral resection.9

We have also established benefits at 30-monthfollow-up after arthroscopic femoral osteochon-droplasty performed in selected patients over 60years of age, who have hip pain and mechanicalsymptoms resulting from cam FAI, is beneficialwith a minimal risk of complications at a meanfollow-up of 30 months.10

1298 F. S. HADDAD, S. KONAN

THE BONE & JOINT JOURNAL

Darkness reigns at the foot of the lighthouseIn the future, we need a well-rounded evidence-based approach tothe management of FAI and hope that this will include qualitativeresearch, the use of improved imaging technologies, prospectiverandomised studies that include non-operative treatments, andresearch into the cost-effectiveness of our interventions.

Hip osteoarthritis often causes functional limitations at anearly age and is an established economic burden on society. Pro-spective long-term longitudinal studies are needed to firmlyestablish the causal relationship between FAI and osteoarthritisand to better understand the role of asymptomatic FAI.

With increasing awareness, the diagnosis of asymptomaticFAI is predictably going to increase further. The clinician needswell-researched tests that can reliably confirm or discard the rel-evance of FAI and/or labral pathology in an individual hip. Theoptimum imaging modality to quantify and qualify the imping-ing anatomy and demonstrate labral tears and chondral injuriesneeds to be established. Any such imaging modality will alsoneed to be cost effective and easily available. Radiologists willneed to nourish and develop this sub-speciality interest and settraining pathways to adequately support our clinicians.

Non-operative management with activity modification andmuscular conditioning needs to be scrutinised to establish effi-cacy and prove long-term benefit. Ultimately, we need to beclear as to who may benefit from surgical treatment as at themoment it sometimes appears as if the hip arthroscopy revolu-tion risks creating a triumph for technique over reason.11

The open dislocation, mini-open and arthroscopic methodsfor treating symptomatic FAI are now well established in termsof reproducibility and safety. Each still has an important role.Arthroscopy is increasingly favoured due to equivalent surgicaloutcomes and the absence of trochanteric osteotomy-relatedcomplications and iatrogenic injuries to the lateral femoralcutaneous nerve seen with the open methods. The debate needsto move forward to establish who and what to treat ratherthan how to surgically approach the hip joint.

Treatment of FAI is not for the occasional hip surgeon. Therole of training, fellowships and research to improve the arma-mentarium of the treating surgeon is well acknowledged. Wehave great misgivings about the focus on the technique andprocedures rather than on understanding hip pathology as awhole. It is unfortunate that hip arthroscopy in the absence ofcareful pre-operative evaluation can lead to inappropriateintervention and some major complications.12-14

Patients, general practitioners, physiotherapists and otherreferring bodies need to be appropriately educated so that aninformed choice exists for surgeon and hospital selection. Inthe UK, many Primary Care Trusts do not currently commis-sion hip arthroscopy on a routine basis. Perhaps the focus herehas to shift to centralising care based on published perfor-mance indicators rather than arbitrary sieves which will onlyserve to add to the allegations of a postcode lottery within theNHS. Cost is now at the heart of health service delivery andestablishing the cost-effectiveness of the treatment of FAI, bothshort- and long-term, is essential.

Above all, the treating surgeon has a responsibility to estab-lish the benefits of surgery for FAI. There is a scarcity of clini-metric evidence to support the use of the current patientreported outcome measures when dealing with non-arthritic hippathology. It may be argued that we still do not understand whatrepresents a successful outcome after FAI surgery. The tools to

measure outcome and functional improvement need to improveif the long-term goal of hip preservation is to be realised.

The Non Arthroplasty Hip Register15 was launched inMarch 2012 and aims to collect longitudinal outcome data forany type of hip condition and/or surgery other than arthro-plasty and acute fractures. Surgeons treating FAI on a regularbasis should register and organise the protocol for the data col-lection for their practice. By collecting multicentre data we willstart to understand the benefits and risks of our interventions.

When going gets toughWe face challenging times. The profession as a whole realises theneed to define the natural history and rate of progression of FAI,the need for appropriate data collection, the need for transpar-ency in establishing the efficacy of the surgical interventions weundertake, and the need for appropriately robust research toshow the superiority of our techniques over other modalities.FAI is an exemplar of the times that we live in today. The Bone& Joint Journal is committed to supporting this path by encour-aging high quality published research in this area.

No benefits in any form have been received or will be received from a commer-cial party related directly or indirectly to the subject of this article.

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8. Malviya A, Stafford GH, Villar RN. Impact of arthroscopy of the hip for femoroac-etabular impingement on quality of life at a mean follow-up of 3.2 years. J Bone JointSurg [Br] 2012;94-B:466–470.

9. Schilders E, Dimitrakopoulou A, Bismil Q, Marchant P, Cooke C. Arthroscopictreatment of labral tears in femoroacetabular impingement: a comparative study ofrefixation and resection with a minimum two-year follow-up. J Bone Joint Surg [Br]2011;93-B:1027–1032.

10. Javed A, O’Donnell JM. Arthroscopic femoral osteochondroplasty for cam femo-roacetabular impingement in patients over 60 years of age. J Bone Joint Surg [Br]2011;93-B:326–331.

11. Colvin AC, Harrast J, Harner C. Trends in hip arthroscopy. J Bone Joint Surg [Am]2012;94:23.

12. Papavasiliou AV, Bardakos NV. Complications of arthroscopic surgery of the hip.Bone Joint Res 2012;1:131–144.

13. Matsuda DK. Acute iatrogenic dislocation following hip impingement arthroscopicsurgery. Arthroscopy 2009;25:400–404.

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15. British Hip Society. The Non Arthroplasty Hip Register. http://www.britishhipsoci-ety.com/NAHR (date last accessed 20 August 2013).