This review compared tourniquet assisted surgery with non-tourniquet assisted surgery during arthroscopic knee procedures. It concluded that the limited evidence suggested that tourniquet improved operative visualisation during arthroscopic anterior cruciate ligament reconstruction knee surgery. The authors' conclusions may not be reliable given the poor quality of included trials, the questionable synthesis approach and other methodological concerns.

To compare the effectiveness of tourniquet assisted surgery with non-tourniquet assisted surgery during arthroscopic knee procedures.

The following databases were searched from inception to December 2008 without language restriction: MEDLINE, EMBASE, CINAHL, AMED and the Cochrane Library. Search terms were reported. The following sources were searched for unpublished studies: System for Information on Grey Literature in Europe (SIGLE), National Technical Information Service, National Research Register (UK), UKCRN Portfolio Database, and Current Controlled Trials database. Reference lists of relevant publications were also screened. Study authors were contacted for additional studies.

Randomised controlled trials (RCTs) and non-randomised controlled trials that compared tourniquet assisted with non-tourniquet assisted arthroscopic knee surgery, in patients of at least 16 years old, were eligible for inclusion.

The primary review outcomes were intra-operative difficulties and surgical field visibility. Secondary outcomes were pain, intra-operative blood loss, postoperative blood loss, operation time, range of motion, muscle strength, and complications (including deep vein thrombosis, pulmonary embolism, neurological impairment and wound healing disorders).

The majority of included trials evaluated tourniquet with 444 non-anterior cruciate ligament reconstruction arthroscopic knee procedures, whilst the other trials evaluated tourniquet with 167 arthroscopic anterior cruciate ligament reconstructions. Where reported, tourniquet inflation pressures ranged from 100 to 450mmHg, and the duration of tourniquet application ranged from 17.1 to 94 minutes. The mean age of included patients ranged from 22 to 47.7 years.

Two reviewers independently assessed studies for inclusion, with any disagreement resolved by consensus.

The quality of studies was assessed using the Cochrane Bone, Joint and Muscle Trauma Group quality assessment tool, a scale evaluating: allocation concealment; intention-to-treat analysis; blinding; follow-up; comparability of baseline characteristics; and clearly defined eligibility criteria, interventions and outcomes.

Two reviewers independently performed the validity assessment, with any disagreement resolved by consensus.

Data were extracted on the mean and standard deviation. Trial authors were contacted for additional data. When data could not be obtained from the authors, mean and standard deviation were extracted from graphical illustrations.

Two reviewers independently performed the data extraction.

A random-effects model was proposed to pool the mean difference of each outcome. Statistical heterogeneity was assessed using X² and I² statistics. It was unclear whether a pooled measure was calculated. It appeared that most outcomes were synthesised narratively. Subgroup analysis was conducted on different surgery procedures (anterior cruciate ligament versus non-anterior cruciate ligament).

Nine trials (n=525 patients) were included in the review. The sample size ranged from 19 to 120 participants. All the trials clearly defined the appropriate outcome measures, but the majority did not clearly define baseline variables. No trial used the intention-to-treat analysis. Allocation concealment was poorly described in most trial. Blinding was inadequate in the majority of trials.

Arthroscopic anterior cruciate ligament reconstruction knee surgery with a tourniquet was significantly associated with less operative visualisation difficulties (p<0.05), compared with surgery without a tourniquet. There were no significant differences in visual analogue scale pain, blood loss, operation time, and complications between the two groups.

No significant heterogeneity was observed. The results of subgroup analyses were also reported.

The limited evidence suggested that tourniquet improved operative visualisation during arthroscopic anterior cruciate ligament reconstruction knee surgery. Further research is required to address this research question.

This review's inclusion criteria were clear. Relevant sources were searched for both published and unpublished studies, without language restriction, minimising the potential for both publication and language biases. Sufficient attempts were made to minimise the errors and biases in the review process.

Relevant criteria were used to examine the trial quality. Statistical heterogeneity was assessed using appropriate statistics, but it appeared that the authors incorrectly assessed their values. Given the low degree of statistical heterogeneity, the decision to adopt a narrative synthesis may not have been appropriate. Few details were provided on whether the included patients received thromboprophylaxis or exsanguination. Results were interpreted based on the direction of effect without details of relevant data, which made it difficult to verify the authors' interpretation.

In light of the poor quality of included trials and methodological concerns outlined above, the authors' conclusions may not be reliable.

Practice: The authors did not state any implications for practice.

Research: The authors stated that further well-designed RCTs are required to assess possible risks and benefits of using a tourniquet during arthroscopic knee procedures. Future trials should compare surgery procedures that use different tourniquet durations and tourniquet inflation pressures. They should also evaluate the outcome of quality of life and perform a economic evaluation.

Not stated.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.