Traction force for peroperative hip dislocation in hip arthroscopy

Abstract

Objectives: Traction force widens the joint space during hip arthroscopy. It is unclear how much the traction force varies and if it is related to the joint space widening. Main goal of our study was to measure the amount of force needed to widen the hip joint. Second goal was to study the relation between this force and the amount of joint space widening. Methods: Traction force was measured in 27 patients (of whom 24 female, mean age 41) during arthroscopy. Measurements were performed before the procedure, after vacuum seal release and after capsulotomy. Joint space widening was measured with fluoroscopy and was calibrated. Friedman and Wilcoxon tests were used to measure differences in traction. The Spearman’s rho correlation coefficient was used to identify a correlation in traction force and joint space widening. Regression analyses were used to identify relations between age, body mass index (BMI), hip degeneration and traction force. Results: The median traction force before arthroscopy was 714 N, lowered to 520 N after vacuum seal release and to 473 N after capsulotomy ( p < 0.001). Median joint space widening was 8.8 mm. Spearmans’ rho correlation between traction force and joint space widening was ‒0.13. Discussion: Median traction force of 714 N resulted in 8.8 mm of joint space widening. This traction force was significantly lowered by 200 N after release of the vacuum seal of the hip and 250 N after additional capsulotomy without loss of joint space narrowing. No significant relation was identified for age, BMI or progression of the Kellgren-Lawrence classification for hip degeneration and traction force. Netherlands Trial Registry number 8610

The effects of venting and capsulotomy on traction force and hip distraction in hip arthroscopy

“…Roling et al . [ 14 ] measured the effects of both venting and capsulotomy on traction force with a desired initial distraction distance of 10 mm. The authors found a 16% reduction in traction force after venting and a 9% reduction in traction force following capsulotomy.…”

“…[ 4 ] and Roling et al . [ 14 ] documented the change in traction force after each intervention but did not report corresponding changes in distraction distance which presumably occurred, as neither study specifically fixed the distraction distance. The current data suggest that distraction distance increases over the course of venting and capsulotomy by ∼1.50–2.25 mm on average, depending on the size of the femoral head.…”

“…Two prior studies have demonstrated benefit of venting and capsulotomy in a human model [ 4 , 14 ]. Ellenrieder et al .…”

“…Roling et al . [ 14 ] demonstrated a 16% reduction in traction force after venting and a 9% reduction in traction force following capsulotomy. Importantly, both of these previous studies measured the effects of venting and capsulotomy on traction force alone without considering the effects on distraction.…”

Letter concerning “Traction force for peroperative hip dislocation in hip arthroscopy” by Röling et al.

“…We read with great interest and appreciation the article titled “Traction force for peroperative hip dislocation in hip arthroscopy” by Röling et al 1 that appeared in Hip International in April 2019.…”