Histological findings of tendon-bone healing following anterior cruciate ligament reconstruction with hamstring grafts.
BACKGROUND
The purpose of the study was the histological examination of tendon-bone healing of hamstring grafts after anterior cruciate ligament (ACL) reconstruction.


METHODS
During five arthroscopies done 6-14 months after ACL reconstructions, biopsies of the wall of the former drilled femoral canal were obtained. Four patients were primarily operated on using a suspending device (Endobutton, Acufex Microsurgical, Mansfield, MA, USA, and Transfix, Arthrex, Naples, FL, USA) for femoral fixation, one patient was reconstructed with a biodegradable interference screw directly inserted between the tendon and the wall of the canal. Biopsies were obtained using a tube harvester during re-arthroscopy. Three grafts were stable, two grafts were unstable, and revision of the ACL was performed.


RESULTS
Histologically, in the four cases of reconstruction with a button or a rectangular pin, biopsies resembled granulation tissue without insertion of fibers between the tendon tissue and the bony wall. A wide area of woven bone was noted adjacent to the pre-existing lamellar bone. In contrast, the tendon-bone junction in the knee reconstructed with a biodegradable interference screw resembled a zone of metaplastic fibrous cartilage between the tendon graft and the lamellar bone. Collagen fibers connecting the tendon-bone interface occurred under polarized light microscopy.


CONCLUSIONS
We conclude that the use of hamstring grafts for ACL reconstruction can lead to different histological pattern of tendon-bone healing. Micromotion of the hamstring graft inside the drilled canal can be play a role in tendon-bone healing.
Marienkrankenhaus Düsseldorf-Kaiserswerth, An St Swidbert 17, 40489 Düsseldorf, Germany. nebelung@kmr-kliniken.de
W
W
Nebelung
R
R
Becker
D
D
Urbach
M
M
Röpke
A
A
Roessner
D000328:Adult; D016118:Anterior Cruciate Ligament / Q000473:pathology* / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D001182:Arthroscopy / Q000379:methods; D001707:Biopsy, Needle; D005260:Female; D005500:Follow-Up Studies; D006085:Graft Survival; D006801:Humans; D007150:Immunohistochemistry; D015601:Injury Severity Score; D007718:Knee Injuries / Q000473:pathology* / Q000601:surgery; D008297:Male; D016059:Range of Motion, Articular; D019651:Plastic Surgery Procedures / Q000379:methods*; D020127:Recovery of Function; D012189:Retrospective Studies; D012494:Sampling Studies; D013710:Tendons / Q000473:pathology* / Q000637:transplantation*; D016896:Treatment Outcome; D014945:Wound Healing / Q000502:physiology