Interportal and T-type capsulotomy came out the same at two years

Design

retrospective cohort with 1:4 propensity score matching, Level III, minimum 2-year follow-up

Population

258 patients undergoing hip arthroscopy with capsular closure (52 interportal, 206 T-type), mean age 32.7 years

Primary outcome

patient-reported outcomes, achievement of clinically significant thresholds, reoperation-free survival

Effect

MCID 93.5% vs 92.8%; PASS 88.2% vs 83.0%; reoperation-free survivorship 98% vs 98%

Fifty-two hip arthroscopies with interportal capsulotomy were propensity matched 1:4 to 206 with T-type capsulotomy, by age, sex and body mass index, from operations performed between October 2020 and November 2022 with at least two years of follow-up. Every patient had capsular closure.

Nothing separated after surgery. Postoperative alpha angles were the same (40.7 against 40.9 degrees). No postoperative patient-reported outcome differed. Achievement of the minimal clinically important difference was 93.5% against 92.8%, patient acceptable symptom state 88.2% against 83.0%, substantial clinical benefit 78.4% against 77.5%, and reoperation-free survivorship 98% in both groups. The one difference was a larger fall in the PROMIS pain interference score in the interportal group, from a baseline that was worse to begin with — which is what regression to the mean looks like.

The conditional in the authors' conclusion is the operative part: this holds when capsular closure is performed, and for patients who do not need the extra visualisation a T-capsulotomy provides. It is not evidence that the capsule can be treated casually; it is evidence that where either technique would do, the choice does not appear to cost the patient anything.

For a surgeon who extends to a T because the view is inadequate, this is reassurance rather than a reason to stop. For one who does it routinely, it removes the outcome argument for the larger capsulotomy.

• Choose the capsulotomy that gives the view the case needs — neither technique showed an outcome advantage at two years
• Close the capsule: every patient in both arms had closure, and the finding does not extend to unrepaired capsulotomy
• Do not extend to a T-capsulotomy for expected outcome benefit; extend it for visualisation
• Expect around 98% reoperation-free survivorship at two years with either technique in this setting
• Read the pain interference difference as baseline imbalance rather than a technique effect

Why it matters

The capsulotomy choice has been argued on biomechanics; at two years it does not show up in what patients report.

Don't overread it

A matched cohort of 52 against 206 cannot establish equivalence, and the findings apply only where the capsule is closed.

The statistics, in plain English

Propensity matching on age, sex and body mass index balances only those three things; it cannot balance why a surgeon chose one capsulotomy for a given hip. The 1:4 match means the interportal group is small at 52 patients, so a modest real difference could easily hide inside these results — this is an absence of evidence rather than strong evidence of equivalence. The one significant difference, a bigger drop in pain interference in the interportal group, started from a worse baseline score, and groups that start further from the mean move further towards it regardless of treatment.

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