A Characterization of Sensory and Motor Neural Dysfunction in Patients Undergoing Hip Arthroscopic Surgery: Traction- and Portal Placement-Related Nerve Injuries.

BACKGROUND

There is a paucity of prospectively collected data as they relate to nerve injuries after hip arthroscopic surgery. Studies describing the relationship of neurological injuries to portal placement and the duration and magnitude of traction force with regular and standardized patient follow-up protocols are limited.

PURPOSE/HYPOTHESIS: The purpose of this study was to characterize nerve deficits in a series of patients undergoing hip arthroscopic surgery as these deficits relate to axial traction and portal placement. It was hypothesized that in patients who presented without nerve deficits after surgery, the magnitudes of traction-related measurements would exceed previous recommendations based on expert opinion (<50 lb). Additionally, it was hypothesized that sensory disturbance would commonly be observed (≥16%) localized to the distal anterolateral thigh related to portal placement.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 45 patients scheduled to undergo hip arthroscopic surgery between July 2012 and February 2014 were included in this study. Traction force was measured and recorded every 5 minutes during surgery, and patients were assessed by a physical examination for deficits in light touch sensitivity at all lower extremity dermatomes preoperatively and at 3 weeks, 6 weeks, 3 months, and 1 year postoperatively. Patients were also tested for strength deficits and rated on the manual muscle testing grading scale. Patients reported modified Harris Hip Score (mHHS), Hip Outcome Score-Activities of Daily Living and -Sport subscales (HOS-ADL and HOS-Sport, respectively), Short Form-12 (SF-12) mental and physical component summaries, and international Hip Outcome Tool-12 (iHOT-12) scores preoperatively and at 1 year postoperatively.

RESULTS

Thresholds for maximum traction force, mean traction force, duration of traction, and traction impulse were 120 lb, 82 lb, 61 minutes, and 7109 lb·min, respectively, below which no patients presented with sensory or motor dysfunction thought to be related to traction. A minority (17.8%) of patients presented with highly localized, distal anterolateral sensory deficits suggestive of injuries related to portal placement, and 2.2% of patients presented with perineal numbness localized to the distribution of the pudendal nerve. All nerve deficits had resolved by 1-year follow-up.

CONCLUSION

This study suggests that it may be possible to apply more axial traction force for a longer duration than expert opinion has previously suggested, without significant and, in the majority of cases (82.2%), any traction-related short-term complications. Transient traction- and portal placement-related nerve injuries after hip arthroscopic surgery may be more frequent (31.1% in this study) than have been reported historically.