Quadriceps tendon autograft diameters are routinely above 8 mm, and preoperative size estimation before anterior cruciate ligament reconstruction may not be necessary for this graft type: A systematic review

PURPOSE: To identify values of reported quadriceps tendon (QT) autograft diameter and length in anterior cruciate ligament reconstruction (ACLR), and to identify methods to predict these parameters. METHODS: A search was conducted across three databases from inception to 30 March 2024. Data on study characteristics, demographics, anthropometric data, imaging techniques, and QT autograft or harvested QT tendon parameters were extracted. Values quantifying the statistical strength of associations between imaging or anthropometric characteristics and graft or tendon parameters as well as for associations between these parameters and postoperative outcomes were recorded. RESULTS: A total of 3633 patients were included. The weighted mean QT autograft diameter and length were 8.9 (standard deviation [SD]: 0.7, range: 7.8-10.4) mm and 8.1 (SD: 1.3, range: 5.6-9.3) cm, respectively. A total of 93.8% of studies that reported mean QT autograft diameter found a value of 8 mm or greater. The QT groups had similar or significantly greater mean autograft diameter compared to the hamstring tendon (HT) groups in 91.7% of studies that reported significance. Regarding MRI measurements, 71.4% of the correlation coefficients reported showed a moderate positive correlation, 28.6% showed a low positive correlation and 14.3% showed a high positive correlation. Regarding anthropometric characteristics, 33.3% and 16.7%, 16.7% and 14.3% of studies that reported on the relationship between QT autograft diameter and height, weight, body mass index or age, respectively, found a low positive statistically significant correlation. Only statistically nonsignificant associations were reported between QT autograft parameters and post-operative outcomes and complications. CONCLUSIONS: QT autografts used in ACLR have a mean diameter of 8 mm or greater and are consistently larger than HT autografts. Preoperative MRI measurements are better than anthropometric characteristics at predicting QT autograft parameters; however, preoperative prediction may not be necessary for this graft type. QT autograft parameters were not found to be significantly associated with any post-operative complication or outcome. LEVEL OF EVIDENCE: Level IV.