Improving the Treatment of Anterior Cruciate Ligament Tears in Norway With Register-RCTs - Who Should Have Surgery

Despite years of research on treating ACL injuries, it remains uncertain who should undergo reconstructive surgery and who should not.

Our project aims to provide definitive answers to these important clinical questions affecting more than 4,000 patients each year in Norway. We will provide this information by conducting a large comparative effectiveness trial of standard treatments for ACL deficiency. This RCT exploit the infrastructure of the Norwegian National Knee Ligament Registry (NNKLR), which uniquely include non-surgically treated ACL-tears and has almost complete coverage of surgical reconstructions. Our multi-center register-RCT design considerably reduces costs and enables us to more rapidly include many more patients. Consequently, the design and study size will give the results excellent external validity.

Surgery or not? It is estimated that 50% of patients with an ACL tear are treated surgically with a reconstruction.[1, 2] The majority of patients are young and active.[3] The general consensus in Scandinavia is that patients who manage to regain acceptable knee function after active rehabilitation alone should not initially have surgery. This treatment algorithm is supported mainly by only one high-quality randomized controlled trial.[4, 5] Prospective studies have reported that the functional recovery, the long term patient outcome and the radiographic sign of osteoarthritis are similar between patients treated surgically or non-surgically.[6-8] However, conclusion about cause and effect cannot be made due to the study designs. A recent Cochrane review concluded that there is a low-quality evidence that there was no difference between surgical and non-surgical treatment, and studies with high external validity is lacking.[9] In the debate of early surgery or not, the risk of subsequent meniscal and chondral injury in an unstable knee is often highlighted by promoters for early surgery. However, the studies behind this argument reports on the correlation between the timing of surgery and concomitant meniscal and cartilage injuries rather than on whether the initial treatment chosen was surgical or non-surgical.[10] This introduces a selection bias as a patients having surgery late may not be representative of all non-surgically treated patients. The findings in a systematic review on this topic by authors in the project group high-light that the uncertain estimate of new meniscal tears after ACL injury should not guide clinical practice for all patients.[11] Even though joint stability often is achieved with surgery, the rate of return to pre-injury activity level after surgery is reported less than 50%, and no consistent results in reduction of the risk of later osteoarthritis have been shown.[12] Admittedly, the risk of serious complications after ACL reconstruction is in general low, however still potentially devastating to the knee function.[13, 14]

About the Norwegian National Knee Ligament Register

The NNKLR was established in 2004 as the world´s first national cruciate ligament register[15]. The NNKLR assesses the outcome based on the Knee Injury and Osteoarthritis Outcome Score (KOOS) which is the gold standard validated patient reported outcome measure (PROM) [16] and by recording revision surgeries or other surgeries to the index knee. Since 2004 cruciate ligament reconstructions performed in Norway have been reported to the register with subsequent registration of revision surgeries and with input of PROM at 2, 5 and 10 years postoperatively. Just below 3000 patients are included yearly in the register. This has provided a unique resource for research and quality assessment, detecting inferior surgical procedures and providing prognostic information to guide practice.[17] Registries have had two major weaknesses limiting overall research impact: