Anterior Cruciate Ligament Reconstruction - Graft failures, surgical techniques and patient-reported outcome measures

Injuries to the anterior cruciate ligament (ACL) can result in increased joint laxity, which often ends participation in competitive sports and may, in the medium to long term, lead to degeneration of the knee. The occurrence of ACL injuries has increased in recent years and, today, ACL reconstruction is one of the most common procedures in orthopaedic surgery. Even though the research on ACL reconstruction is extensive, the optimal surgical technique is yet to be universally accepted. Study I is a comprehensive systematic review evaluating all the clinical studies comparing primary single- and double-bundle ACL reconstruction in the current literature. 60 studies comprising 4,146 patients were included. An analysis of graft failures revealed fewer reported re-ruptures after double-bundle (DB) reconstruction compared with single-bundle (SB), 19 and 44 respectively. However, only two of the 23 studies reporting re-ruptures reported statistical difference, both in favour of the DB reconstruction. Up to 45% of the studies revealed a superior outcome in DB reconstruction in terms of less antero-posterior (AP) laxity, and measurements of rotatory laxity revealed superior results in DB reconstruction measured with pivot shift and navigation in 18/42 and 9/20 studies respectively. The other studies found no difference. Patient-reported outcome measures (PROMs) and functional outcomes did not differ to a large extent; however, differences when identified were almost exclusively in favour of the DB reconstruction. Study II is an observational comparative study based on data from the Swedish National Knee Ligament Register over a seven-year period with a total of 22,740 primary ACL reconstructions included. The purpose was to compare ACL revision rates and PROMs between SB and DB ACL reconstructions. The study included 16,281 SB and 510 DB reconstructions, with a revision rate of 2.1% and 1.6% respectively. No differences were found in terms of either the revision rate between the groups or the KOOS or EQ-5D. Study III is a retrospective comparative study based on 251 patients between 14 and 50 years of age at the time of a primary ACL reconstruction, with a mean 3.4 ± 1.3 years follow-up, to determine predictors of ACL revision. In overall, 21 (8.4%) patients underwent an ACL revision. A multivariate logistic regression analysis revealed that young age and the use of allografts at the primary reconstruction were independent predictors of an ACL revision. Study IV is a randomised controlled trial consisting of 193 patients who underwent a primary ACL reconstruction using either hamstring tendon (HT) or patellar tendon (PT) autografts, to investigate the long-term clinical and radiographic results. At the follow-up, 147 (76%) patients were examined; 86 patients in the HT group with a mean 191.9 ± 15.1 months follow-up and 61 patients in the PT group with mean 202.6 ± 10.4 months follow-up. Seven patients (8.1%) in the HT group and four patients (6.6%) in the PT group had an ACL graft failure in the ipsilateral knee, while six patients in both groups (7.0% HT group, 9.8% PT group) sustained an ACL graft failure to the contralateral knee. Knee laxity measurements revealed significantly more patients with a negative pivot shift in the HT group compared with the PT group (71% vs 51%; p=0.048); however, no differences were found in terms of AP laxity. The patients in the PT group had more difficulty knee-walking (p=0.049). There were no differences between the two groups in terms of PROMs, range of motion in the reconstructed knee or radiographic signs of osteoarthritis (OA). However, in both groups, more radiographic signs of OA were found in the reconstructed knee than in the contralateral healthy knee