Graft-tunnel mismatch in endoscopic anterior cruciate ligament reconstruction

Abstract

The results of a study conducted on 50 knees endoscopically reconstructed for an anterior cruciate ligament (ACL) lesion with a free bone-patellar tendon-bone graft and 9 cadaver knees are reported. The mean lengths of the patellar tendon (45.48 +/- 4.71 mm) and intra-articular ACL graft (20.44 +/- 1.98 mm) were measured in the operated knees. The mean length of the tibial bone tunnel (51.62 +/- 2.60 mm) was also measured with a tibial guide at 55 degrees. No statistically significant correlation was found between these three measurements. The length of the patellar tendon was weakly correlated with body height. Measurement of the tibial tunnel on the cadaver knees with increasing degrees of inclination revealed a mean length increase of 0.68 mm per degree (confidence limits: 0.49-0.86). Comparison between the tunnel lengths obtained with the guide and those measured with a Kirschner wire showed a mean difference of 2.3 mm. It is thus desirable to make the tunnel about 53 mm long to ensure excellent fixation of a 28 mm bone block with a 25 mm interference screw. Correct measurement of the anatomical structures involved is in any event an essential requirement for proper execution of the surgical technique.

How to Avoid Graft-Tunnel Length Mismatch in Modified Transtibial Technique for Anterior Cruciate Ligament Reconstruction Using Bone-Patellar Tendon-Bone Graft

“… 21) The disadvantages include poor biomechanical stability and technical errors, which can be resolved with use of the BPTB graft with an appropriate length. In our series, the length of patellar tendon was 43.1 mm, shorter than that in previous reports (48.4 mm, 9) 45.48 mm, 13) and 52.6 mm 22) ). Presumably, this might arise from differences in the morphotype and ethnicity.…”

“…The results of the study can be summarized as follows: (1) The mean length of tibial tunnel was 33.7 mm (range, 28 to 40 mm), which is significantly shorter that of the traditional TT technique (42.1 mm 9) and 51.62 mm 13) ). (2) The total mean length of tunnels was 86.8 mm, and the mean length of BPTB graft was 90.7 mm.…”

Influence of the bone block position on the tunnel enlargement in ACL reconstruction

“…Due to different operating techniques with femoral bone block anchoring close to the joint, considerably larger tibial bone block depths from 23.6–15.6 mm, respectively were described. 26,27 Only publications concerning the effect of the bone block position on the tunnel enlargement at the tibial side are available. 20,26,32 …”

“…The length of the patellar tendon varied between 48.4±6.0 mm and 45.5±4.7 mm respectively. 27,33 Therefore the intraarticular portion of the transplant is mathematical between 36.9 mm and 34.0 mm, respectively. Li described a length of the native ACL in the anteromedial bundle of only 32.5±2.8 mm.…”

“…These factors may explain part of the etiology of the tunnel enlargement, but the correlation between bone block depth and tunnel enlargement has only been investigated in respect of the tibia. 20,26,27 …”