- Discussion:
-
anatomy of ACL;
-
ACL biomechanics;
-
graft tunnel sites / isometry:
- hamstring ACL reconstruction is an alternative to
bone patellar bone graft fixation;
- double looped hamstring graft is more than twice as strong as normal ACL,
as compared to a bone patella bone (which is 1.3 times as strong);
- this is true because more cicular shaped hamstring tendons have larger cross sectional area than a similarly sized BPB graft;
- 8 mm double graft has a cross sectional area of 50 sq mm vs a 10 mm BPB graft which has a cross sectional area of 35-40 sp mm;
- some surgeons elect to use hamstrings in patients who have had previous patellar tendon harvest or who
have pre-existing patellofemoral arthrosis;
- in the uncommon case of concomitant ACL-PCL ruptures, often the bone patella bone graft is used for the PCL reconstruction, and
the hamstrings are used for ACL reconstruction;
- main disadvantage of hamstrings is that the reconstruction is less stiff than BPB grafts, since a longer
graft length (with fixation outside of femoral and tibial tunnels) will undergo more strain;
- PreOp Evaluation:
-
Surgical Technique:
-
positioning and setup:
-
hamstring harvest:
-
knee arthroscopy
-
notchplasty:
-
tibial tunnel:
- consider undersizing reaming diameter and then using dilators at the distal aspect of the tunnel;
- this will better accomodate the distal end of the graft which often is of larger diameter than the rest of the graft;
- using this technique, allows the distal (wider diameter) end of the graft to act as a "stop" to proximal migration (in addition to the interference screw);
-
femoral tunnel:
- consider more posterior femoral tunnel with hamstring grafts noting their increased flexibility compared to bone patella bone grafts;
-
graft fixation:
- after interference screw fixation of the tibial graft, there will often be a large residual portion of tendon graft which overhangs from the tibial tunnel;
- these overhanging graft ends may be sutured to the proximal tibial periosteum for additional fixation;
- Post Op Care of ACL Reconstructions:
- References:
The use of hamstring tendons for ACL reconstruction. CH Brown JR et al.
CORR. Vol 12. p 273. 1993.
Arthroscopically Assisted Reconstruction of the Anterior Cruciate Ligament; A prospective randomized analysis of three techniques.
D.B. O'Neill MD.
JBJS Vol 78-A No. 6, June 1996.
Clinical Outcome of Anterior Cruciate Ligament Reconstruction with Quadrupled Hamstring Tendon Graft and Bioabsorbable Interference Screw Fixation.
A Randomized Comparison of Patellar Tendon and Hamstring Tendon Anterior Cruciate Ligament Reconstruction.
Anterior Cruciate Ligament Reconstruction with a Four-Strand Hamstring Tendon Autograft.
Muscle and Tendon Morphology After Reconstruction of the Anterior Cruciate Ligament with Autologous Semitendinosus-Gracilis Graft.
Anterior Cruciate Ligament Reconstruction: Bone-Patellar Tendon-Bone Compared with Double Semitendinosus and Gracilis Tendon Grafts
Hamstring Tendon Versus Patellar Tendon Anterior Cruciate Ligament Reconstruction Using Biodegradable Interference Fit Fixation.
