ISAKOS Congress 2021

2021 ISAKOS Biennial Congress Paper


Treatment of Bilateral Hip Femoroacetabular Impingement: Simultaneous or Staged?

Gen Lin Foo, MD, Singapore, Singapore SINGAPORE
Catherine J. Bacon, PhD, MSc, BSc, BPhed(Hons), Auckland NEW ZEALAND
Matthew J. Brick, MBChB, FRACS, Auckland NEW ZEALAND

Orthosports, Auckland, Auckland, NEW ZEALAND

FDA Status Not Applicable


Our study sets outs to assess the clinical outcome and complications rates between patients undergoing simultaneous versus staged surgery for bilateral hip femoroacetabular impingement.



Femoroacetabular impingement (FAI) typically involves both hips and presents a surgical dilemma when symptomatic at the same time. Bilateral simultaneous surgery can reduce the overall rehabilitation period compared to a staged surgery. However, the disadvantages are longer surgical time and possible higher complications. We hypothesize that there is no difference in the outcome and complication rates between bilateral simultaneous and staged surgery for FAI.


Patients who underwent simultaneous and staged bilateral primary hip arthroscopy for FAI between June 2005 and December 2018 were identified from our surgical database. Those who had their second surgery within 1 year of their index surgery were included in the staged group. The control group comprised patients who underwent a unilateral hip arthroscopy within the same time-frame. Patient Reported Outcome Measures (PROMs) including the 12-item International Hip Outcome Tool (iHOT-12), Non-Arthritic Hip (NAH) Total and Hip Disability and Osteoarthritis Outcome (HOOS) scores were collected pre-operatively and at regular intervals post-operatively up to 10 years. Two-year follow-ups scores were included in analysis if they were available, or later follow-ups if they were not. We also gathered data on complications and revision surgery rates including conversion to arthroplasty from a national registry.


A total of 186 patients (372 hips) in the bilateral simultaneous and 83 patients (166 hips) in the bilateral staged were compared with 1275 patients in the unilateral group. The median duration between staged surgeries was 57 days (range 14 to 347 days). Simultaneous and staged surgeries did not differ in follow-up duration, patients’ age, gender, or body mass index, although patients in the unilateral group were older (37±12 years compared with 30±11 years in the bilateral groups; p<0.001). Two-year minimum post-operative scores in all 3 groups were significantly improved compared to their pre-operative scores (bilateral simultaneous iHOT-12 pre-op 37.0±18.7 and post-op 74.7±22.2; bilateral staged iHOT-12 pre-op 41.2±19.3 and post-op 69.4±25.6 and unilateral iHOT-12 pre-op 39.3±20.4 and post-op 75.3±23.4; p<0.001 for all changes). We found a significant difference in several 2-year minimum post-operative scores between the 3 groups after statistically adjusting for the differing pre-operative scores. Overall, the staged group performed worse in all scores (p<0.05 for all apart from HOOS Sports subscale and NAH Total scores). There was no difference in revision rates between groups, but simultaneous surgeries were less likely to undergo conversion to arthroplasty within the study’s 6.4±2.6 years follow-up duration (1.1% conversion rate for simultaneous, versus 3.6% in staged and 4.5% in unilateral; p=0.009).


Patient who underwent bilateral simultaneous hip arthroscopy for FAI did better in most PROM scores than staged surgery at the 2-year follow-up period, and were less likely within the study time-frame to require conversion to arthroplasty. These differences are likely due to selection for simultaneous versus staged procedures.

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