- Design
- prospective single-centre cohort with sensor-measured traction and confidential questionnaires, Level III
- Population
- 93 patients (mean age 36.4 years, 55% male) after primary unilateral hip arthroscopy supine on a perineal post
- Primary outcome
- incidence, breadth and duration of pudendal nerve palsy symptoms
- Effect
- 83% acutely, 26% at 3 months, 14% beyond 6 months, none at 12; OR 1.59 per additional 10 min traction (95% CI 1.12-2.37)
Ninety-three patients having primary unilateral hip arthroscopy supine on a perineal post were screened prospectively and confidentially for pudendal nerve symptoms at 2 and 6 weeks and 3, 6 and 12 months, with validated sexual function questionnaires. Traction force and duration were measured by a sensor on the post. Anyone with pre-existing symptoms, including sexual dysfunction, was excluded.
Eighty-three per cent had symptoms consistent with pudendal nerve palsy in the acute period — perineal numbness in 75%, paraesthesia in 26%, pain in 18%. Urogenital or sexual dysfunction occurred in 39%, including erectile dysfunction in 22% of men and reduced lubrication in 19% of women. At three months 26% still had symptoms, 14% persisted past six months, and all had resolved by a year.
Traction was the modifiable driver. Affected patients had greater traction force (mean difference 18.1 kg, 95% CI 0.3-37.1) and longer traction time (15.4 minutes, 5.5-25.3), and each additional 10 minutes raised the odds of symptoms by 1.59 (1.12-2.37) against a mean traction time of 80 minutes. Symptoms persisting beyond six weeks tracked with worse hip scores at six months (iHOT-33 difference -14.4, -24.2 to -4.5).
Two things follow, and the first is consent. A complication affecting four in five patients acutely, and sexual function in two in five, is not a footnote — it belongs in the pre-operative conversation with its resolution timeline, which is genuinely reassuring. The second is the operating list. Traction minutes are the lever: plan the sequence so traction is applied late and released early, use the lowest force that gives the view, and record the time, because a duration nobody recorded cannot be reduced. Where postless technique is available and the case allows, this is the argument for it.
- Tell patients before hip arthroscopy that perineal numbness is common and that sexual dysfunction occurred in about two in five, resolving by a year
- Record traction force and duration for every case — each extra 10 minutes raised the odds of symptoms by about 60%
- Sequence the operation so traction goes on as late and comes off as early as the case allows
- Ask about urogenital and sexual symptoms directly at follow-up; patients do not volunteer them
- Flag symptoms persisting beyond six weeks as predicting worse hip scores at six months, and follow those patients more closely
Why it matters
A complication most patients have and few are warned about is a consent problem before it is a technical one.
Don't overread it
This is a single-centre observational cohort — it shows association between traction and symptoms, not that reducing traction prevents them.
The statistics, in plain English
An odds ratio of 1.59 per 10 minutes, with an interval from 1.12 to 2.37, is a real dose-response relationship: the interval stays above 1.0. The traction force difference of 18.1 kg has a lower bound of just 0.3 kg, so the size of that effect is very uncertain even though its direction is not. With 93 patients and 77 affected, the unaffected group is small, which is why these intervals are wide. This is an observational cohort, so shortening traction has not been shown to reduce symptoms — only that longer traction went with more of them.
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