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

PURPOSE: 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).

METHODS

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.

RESULTS

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).

CONCLUSION

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 OF EVIDENCE: Level III, retrospective comparative cohort.