Rupture of the anterior cruciate ligament (ACL) in the knee is a common injury in young, active individuals. It often results in an unstable knee that increases the risk of further knee damage, such as to the knee meniscii. Anterior cruciate ligament injuries in athletic individuals are often treated surgically. Surgery usually entails ACL reconstruction, that involves removing the torn ligament and replacing it with a tendon graft, often taken from another part of the patient's knee. Conservative (non-surgical) interventions are also used as treatment for this injury. This usually takes the form of a progressive rehabilitation programme that includes exercises aimed at improving strength and balance. We aimed to assess the effects of surgical versus conservative interventions for treating ACL injuries.
Results of the search
We performed a systematic literature search (up to 18 January 2016) for studies that compared surgery and conservative interventions for treating ACL injuries. This review identified one study of 121 young, active adults with an ACL injury in the preceding four weeks. The study compared surgery (ACL reconstruction followed by structured rehabilitation) with conservative treatment (structured rehabilitation alone).
The study found there was no difference between surgery and conservative treatment in patient-reported knee scores at two or five years. The study failed to report on the number of participants in each group who had any type of serious or non-serious complications. However, surgery-related complications included three cases of graft rupture in the surgery group and several participants of the conservative treatment group had unstable knees. Twenty-three of the 59 participants in the conservative treatment group (39%) had either reconstruction of the ACL or repair of a meniscus tear within two years and 30 (51%) underwent surgery within five years. There was some evidence that similar numbers of participants in the two groups had surgical treatment of knee meniscal injuries at five years. There was very low-quality evidence that more participants in the surgery group had damage to the knee that could mean that they were at greater risk of developing osteoarthritis.
Quality of the evidence
The quality of the evidence was limited by the availability of data from only one study. The study was also at high risk of bias because the clinicians and participants were not blinded to their treatment. Overall, the quality of the evidence was low, which means that we are uncertain of the study findings and further research may provide evidence that could change our conclusions.
In young, active adults being treated for acute ACL injury, we found no difference between surgery and conservative treatment in patient-reported outcomes of knee function at two and five years. However, many participants with an ACL rupture had unstable knees after structured rehabilitation and opted to have surgery later on.
For adults with acute ACL injuries, we found low-quality evidence that there was no difference between surgical management (ACL reconstruction followed by structured rehabilitation) and conservative treatment (structured rehabilitation only) in patient-reported outcomes of knee function at two and five years after injury. However, these findings need to be viewed in the context that many participants with an ACL rupture remained symptomatic following rehabilitation and later opted for ACL reconstruction surgery. Further research, including the two identified ongoing trials, will help to address the limitations in the current evidence, which is from one small trial in a young, active, adult population.
Rupture of the anterior cruciate ligament (ACL) is a common injury, mainly affecting young, physically active individuals. The injury is characterised by joint instability, leading to decreased activity, which can lead to poor knee-related quality of life. It is also associated with increased risk of secondary osteoarthritis of the knee. It is unclear whether stabilising the knee surgically via ACL reconstruction produces a better overall outcome than non-surgical (conservative) treatment.
To assess the effects of surgical versus conservative interventions for treating ACL injuries.
We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (18 January 2016), the Cochrane Central Register of Controlled Trials (2016, Issue 1), MEDLINE (1946 to January Week 1 2016), MEDLINE In-Process & Other Non-Indexed Citations (18 January 2016), EMBASE (1974 to 15 January 2016), trial registers (February 2016) and reference lists.
We included randomised controlled trials that compared the use of surgical and conservative interventions in participants with an ACL rupture. We included any trial that evaluated surgery for ACL reconstruction using any method of reconstruction, type of reconstruction technique, graft fixation or type of graft.
Three review authors independently screened all titles and abstracts for potentially eligible studies, for which we then obtained full-text reports. Two authors then independently confirmed eligibility, extracted data and assessed the risk of bias using the Cochrane 'Risk of bias' tool. We used the GRADE approach to assess the overall quality of the evidence.
We identified one study in which 141 young, active adults with acute ACL injury were randomised to either ACL reconstruction followed by structured rehabilitation (results reported for 62 participants) or conservative treatment comprising structured rehabilitation alone (results reported for 59 participants). Built into the study design was a formal option for subsequent (delayed) ACL reconstruction in the conservative treatment group, if the participant requested surgery and met pre-specified criteria.
This study was deemed at low risk of selection and reporting biases, at high risk of performance and detection biases because of the lack of blinding and at unclear risk of attrition bias because of an imbalance in the post-randomisation exclusions. According to GRADE methodology, the overall quality of the evidence was low across different outcomes.
This study identified no difference in subjective knee score (measured using the average score on four of the five sub-scales of the KOOS score (range from 0 (extreme symptoms) to 100 (no symptoms)) between ACL reconstruction and conservative treatment at two years (difference in KOOS-4 change from baseline scores: MD -0.20, 95% confidence interval (CI) -6.78 to 6.38; N = 121 participants; low-quality evidence), or at five years (difference in KOOS-4 final scores: MD -2.0, 95% CI -8.27 to 4.27; N = 120 participants; low-quality evidence). The total number of participants incurring one or more complications in each group was not reported; serious events reported in the surgery group were predominantly surgery-related, while those in conservative treatment group were predominantly knee instability. There were also incomplete data for total participants with treatment failure, including subsequent surgery. In the surgical group at two years, there was low-quality evidence of far fewer ACL-related treatment failures, when defined as either graft rupture or subsequent ACL reconstruction. This result is dominated by the uptake by 39% (23/59) of the participants in the conservative treatment group of ACL reconstruction for knee instability at two years and by 51% (30/59) of the participants at five years. There was low-quality evidence of little difference between the two groups in participants who had undergone meniscal surgery at anytime up to five years. There was low-quality evidence of no clinically important between-group differences in SF-36 physical component scores at two years. There was low-quality evidence of a higher return to the same or greater level of sport activity at two years in the ACL reconstruction group, but the wide 95% CI also included the potential for a higher return in the conservative treatment group. Based on an illustrative return to sport activities of 382 per 1000 conservatively treated patients, this amounts to an extra 84 returns per 1000 ACL-reconstruction patients (95% CI 84 fewer to 348 more). There was very low-quality evidence of a higher incidence of radiographically-detected osteoarthritis in the surgery group (19/58 (35%) versus 10/55 (18%)).