Abstract: The updated search resulted in the inclusion of one new study. This review now includes five RCTs with 366 participants. There were more female than male participants (70% were female); their ages ranged from 14 to 53 years. All trials involved ACL reconstructions performed by experienced surgeons. Assessing the studies' risk of bias was hampered by poor reporting of trial methods, and consequently several studies were judged to be 'unclear' for several types of bias. One trial presenting primary outcome data was at high risk of detection bias from lack of clinician blinding and attrition bias from an unaccounted loss to follow-up at two years. We found moderate quality evidence (three trials, 193 participants) of no clinically relevant difference between CAS and conventional surgery in International Knee Documentation Committee (IKDC) subjective scores (self-reported measure of knee function; scale of 0 to 100 where 100 was best function). Pooled data from two of these trials (120 participants) showed a small, but clinically irrelevant difference favouring CAS (MD 2.05, 95% CI -2.16 to 6.25). A third trial (73 participants) also found minimal difference in IKDC subjective scores (reported MD 0.2). We found low quality evidence (two trials, 120 participants) showing no difference between the two groups in Lysholm scores, also measured on a scale 0 to 100 where 100 is best function (MD 0.25, 95% CI -3.75 to 4.25). We found very low quality evidence (one trial, 40 participants) showing no difference between the two groups in Tegner scores. We found low quality evidence (three trials, 173 participants) showing the majority of participants in both groups were assessed as having normal or nearly normal knee function (86/87 with CAS versus 84/86 with no CAS; RR 1.01, 95% CI 0.96 to 1.06). Similarly, no differences were found for our secondary outcome measures of knee stability, loss in range of motion and tunnel placement. None of the trials reported on re-operation. No adverse post-surgical events were reported in two trials (133 participants); this outcome was not reported by the other three trials. CAS use was associated with longer operating times compared with conventional operating techniques: the mean difference in operating times reported in the studies ranged between 9 and 27 minutes. From the available evidence, we are unable to demonstrate or refute a favourable effect of CAS for cruciate ligament reconstructions of the knee compared with conventional reconstructions. However, the currently available evidence does not indicate that CAS in knee ligament reconstruction improves outcome. There is a need for improved reporting of future studies of this technology.

Plain-language summary: We conducted a comprehensive search of medical literature up to 5 July 2013 to find randomized controlled trials (clinical studies where people are randomly put into one of two or more treatment groups) and quasi-randomized controlled trials (e.g. allocation by hospital record number or date of birth) comparing computer-assisted surgery (CAS) of the ACL or PCL with conventional operating techniques not involving CAS in adults. We found five studies for inclusion in this review. These studies involved 366 participants, mainly female (70%), aged 14 to 53 years. All five trials involved ACL reconstruction. We were uncertain about the reliability of study findings due to poor reporting of trial methods and, sometimes, results. Our assessment of the quality of the evidence available for individual outcomes ranged from 'moderate' quality (which means further research may change the estimate) to 'very low' quality (which means we are very uncertain about the estimate). The trials provided some moderate quality evidence that there was no difference between computer-assisted surgery and conventional surgery for patient-reported knee function. There was low quality evidence of no difference between the two groups in self-reported function score and very low quality evidence of no difference in a score measuring activity levels. There was low quality evidence of no difference between the two treatment groups in the number of people assessed by clinicians as having a normal or nearly normal knee function at the final follow-up time. No adverse post-surgical events were reported in two trials; this outcome was not reported by the other three trials. CAS took longer to do than conventional surgery (from 9 to 27 minutes longer). Overall, the currently available evidence does not indicate that CAS in knee ligament reconstruction improves outcome compared with conventional surgery.