Sherman classification
The Sherman Classification is useful in determining which cruciate tears are most likely to be amenable to repair, Type I being the most likely to be successful.
- Type I - avulsion from the femur bone at the top of the notch
- Type II - tear through the substance of the ACL in the upper 1/3
- Type III - mid-substance tear
- Type IV - distal tear
- Type V - avulsion from distal tibia bone
Quote from peer-reviewed paper::
"....When considering suitability for primary repair it appears that femoral sided avulsions should be the initial focus...Significant caution is advised with mid-substance tears as significantly higher failure rates have been shown...."
Citation: Mahapatra P, Horriat S, Anand BS. Anterior cruciate ligament repair - past, present and future. J Exp Orthop. 2018 Jun 15;5(1):20. doi: 10.1186/s40634-018-0136-6. PMID: 29904897; PMCID: PMC6002325.
Technique of cruciate repair
Cruciate repair (where the torn ends are sewn together) had been abandoned some years ago in favour of cruciate reconstruction (where the original ligament is replaced with a graft).
However, with improved understanding of which cruciate tears heal more readily and with improved technology, the procedure is making a comeback, especially in children where any harvested autograft would be too flimsy to use for a reconstruction and where the growth plates are still open and vulnerable to damage from drilling tunnels for a reconstruction.
There are several options for primary repair of the cruciate, but the main concepts include:
preparing the femoral notch attachment site with microfracture and a fibrin clot, to encourage the torn end to re-unite with the bone
augmenting the ligament perhaps with tape, and cinching it back into position
tensioning and securing the repaired ligament to the outer part of the bone with suture anchors or buttons