Hip Rotation and Femoral Anteversion and Its Influence on Traction Force of the Pulled Limb in Hip Arthroscopy.

Background: Several variables may affect the traction force during hip arthroscopy. Specifically, the degree of hip joint rotation may influence the magnitude of traction force during hip arthroscopy. However, there is currently limited research available on this particular issue.

Purpose: To quantify the traction force applied to the pulled limb in various traction states and rotational positions. Additionally, the study aimed to investigate potential correlations between femoral anteversion, BMI, anesthesia methods, and the traction force required for hip dislocation.

Hypothesis: It was hypothesized that traction force in different traction states and rotational positions would be different and that femoral anteversion, body mass index (BMI), and anesthesia methods may influence the traction force needed.

Study Design: Cross-sectional study; Level of evidence, 4.

Methods: Patients who attended the sports medicine clinic of our department and underwent arthroscopic surgery for the diagnosis of femoroacetabular impingement between June and December 2022 were retrospectively evaluated. The traction force at the following 6 key timepoints was measured-initial traction, traction to the operable width, after joint puncture, after capsulotomy, at 20 minutes after capsulotomy, and at 40 minutes after capsulotomy. In each state, the hip was rotated to the internal rotational position, external rotational position, and neutral position. The traction force at different states and positions was recorded and analyzed. The differences in traction force between the different joint capsular physical states and rotational positions were tested by analysis of variance and the Tukey method. The Pearson test was used to analyze the correlation between BMI and femoral anteversion in different groups.

Results: A total of 41 patients were included in this study. The traction force increased after reaching the operable width and decreased significantly after capsulotomy ( < .05). Thereafter, the traction force decreased gradually over time ( < .05). Traction force in the external and internal rotational positions was significantly greater than that in the neutral position, across all states of traction ( < .05). Furthermore, the difference in traction force between the internal and neutral positions, as well as the difference in traction force between the external and neutral positions, was found to be significantly greater than the difference in traction force between the internal and external rotational positions in all traction states ( < .05). The difference between the traction forces in different rotational positions of the hip joint exhibited a negative correlation with femoral anteversion (Pearson correlation coefficient of neutral-internal in states 3, 4, and 5 was -0.33, -0.31, -0.31, respectively; < .05) and a positive correlation with BMI (Pearson correlation coefficient of external-neutral in states 4 and 6 was 0.33 and 0.36, respectively; < .05).

Conclusion: Our findings show that the traction force decreased after joint puncture and capsulotomy and decreased over time during surgery. External or internal rotation increased the traction force. Patients with higher femoral anteversion or lower BMI may need lower traction force. These data may help in minimizing traction forces to help prevent complications due to traction during hip arthroscopy.