Summary

Large claims-based study shows association and increased incidence of ACL reconstructions in FAI population.

Abstract

Objectives:
Femoroacetabular Impingement (FAI) is a common cause of hip pain and can result in decreased mobility to the hip joint. Compensatory movement patterns as a result of restriction of movement and pain in the hip seen in FAI have been demonstrated to increase forces on neighboring joints such as the knee and lumbar spine and are subsequently at risk for injury. Previous studies have demonstrated a high incidence of ACL reconstructions in athletic populations that have been retrospectively diagnosed with FAI. A population level analysis to evaluate the phenomenon of ACL reconstructions in patients with FAI, or the time course of ACL reconstruction relative to FAI surgery has not yet been investigated. This study sought to answer the following questions: (1) Do patients that undergo FAI-related hip arthroscopy have a higher incidence of ACL reconstruction? (2) Does ACL reconstruction tend to precede FAI-related arthroscopy?

Methods

We assessed all patients who underwent hip arthroscopy identified using two FAI-related Current Procedural Terminology (CPT) codes between January 2011 and December 2016 by retrospective analysis of the IBM® MarketScan® Research databases (formerly Truven Health Analytics). Patients were excluded if they did not meet continuous insurance enrollment criteria for two years surrounding the period of interest. The primary outcome was ACL reconstruction as indicated by the corresponding CPT code at any period of time within the database limits (January 2006 – December 2016). We identified 18,649 individuals that underwent hip arthroscopy for FAI between the years of 2011-2016. During this same period, 122,651 patients were treated with an ACL reconstruction. A cohort of 139 unique patients was identified that underwent FAI-related arthroscopy and ACL reconstruction that met inclusion criteria.

Results

The incidence of ACL reconstruction in patients with FAI-related arthroscopy was 0.0075, while the incidence of ACL reconstruction over the same time period in the MarketScan® database was 0.0014 (p < 0.0001). The final cohort with both FAI-related arthroscopy and ACL reconstruction totaled 139 unique patients consisting of 87 women (63%) and 52 men (37%) (p < 0.01). The average age at FAI-related arthroscopy was 33.7 years (SD 13.2 years). On average, patients underwent ACL reconstruction 14 months before FAI-related arthroscopy (95% CI 8.6 – 18.7 months).

Conclusions

Patients who underwent FAI-related arthroscopy were shown to have a significantly higher incidence of ACL reconstruction when compared to the general incidence of ACL reconstruction in this dataset. ACL reconstruction also occurs, on average, before FAI-related arthroscopy suggesting a potential causal or comorbid relationship that requires further investigation.

Level of Evidence: Level II