# Infra‐tubercle osteotomy preserves coronal alignment and reduces anterior laxity compared to retro‐tubercle technique in revision anterior cruciate ligament reconstruction with slope correction

## TL;DR

This study compares two surgical techniques for revising ACL reconstruction and finds that one preserves knee alignment better but requires more hardware removal.

## Contribution

The study provides new comparative evidence on infra-tubercle versus retro-tubercle osteotomy outcomes in revision ACL surgery.

## Key findings

- Infra-tubercle osteotomy showed lower anterior laxity and better coronal alignment preservation compared to retro-tubercle.
- Infra-tubercle osteotomy required more frequent hardware removal and had longer healing times.
- Both techniques achieved similar survivorship and patient-reported outcomes.

## Abstract

To compare infra‐tubercle (IKO) versus retro‐tubercle (RKO) slope‐reducing osteotomy performed with revision anterior cruciate ligament reconstruction (ACLR) on survivorship, anterior laxity, alignment, union, complications and patient‐reported outcome measures (PROMs).

Retrospective comparative cohort at a tertiary centre including 107 consecutive revision ACLR + slope‐reducing osteotomy cases (IKO n = 50; RKO n = 57). Primary outcomes were Kaplan–Meier survivorship for (1) revision‐only and (2) global failure (earliest of revision or instrumented anterior laxity > 5 mm). Secondary outcomes included Rolimeter side‐to‐side laxity at 2 months/1 year/2 years, radiographic posterior tibial slope (ΔPTS) and hip–knee–ankle angle (ΔHKA), union time, complications/reoperations and knee injury and osteoarthritis outcome score (KOOS). Between‐group comparisons used t‐tests/χ²; survival was compared by the log‐rank test. Significance p < 0.05.

At mean follow‐up of 27.9 ± 4.4 months, crude revision rates were 5.26% (3/57; 95% confidence [CI]: 1.8%–14.4%) for IKO versus 20.0% (10/50; 95% CI: 11.2%–33.0%) for RKO (p = 0.048). Five‐year Kaplan–Meier survivorship estimates showed no statistically significant differences at all endpoints. IKO demonstrated significantly lower instrumented laxity at all time points: 2.4 ± 2.1 versus 3.3 ± 2.0 mm at 2 months (p = 0.034), 3.5 ± 2.3 versus 4.8 ± 2.7 mm at 1 year (p = 0.010), and 4.0 ± 2.9 versus 5.8 ± 4.2 mm at 2 years (p = 0.013). Coronal alignment changes differed significantly between groups (ΔHKA + 0.45° ± 0.58° for IKO vs. −1.32° ± 1.20° for RKO, p < 0.001). PTS reduction was comparable between groups (ΔPTS −8.20° ± 1.61°, 95% CI: −8.6 to −7.8 vs. −7.90° ± 1.74°, 95% CI: −8.4 to −7.4, p = 0.35). Hardware removal was more frequent following IKO (38.8% vs. 17.2%, p = 0.016). Union was achieved universally in both groups, though healing time was longer after IKO (4.0 ± 0.9 vs. 3.2 ± 0.6 months, p < 0.0001).

In revision ACLR for elevated PTS, IKO and RKO yield comparable survivorship and PROM gains. IKO demonstrated better preservation of coronal‐plane alignment and lower residual anterior laxity, at the trade‐off of more frequent elective hardware removal and slightly longer time to union. These data can inform technique selection and counselling.

Level III, retrospective comparative cohort.