MRI of broken bioabsorbable crosspin fixation in hamstring graft reconstruction of the anterior cruciate ligament.
OBJECTIVE
To report seven cases of broken bioabsorbable femoral crosspins identified by MRI in evaluation of hamstring grafts of the anterior cruciate ligament.


METHODS
Seven cases of broken bioabsorbable crosspins utilized in femoral fixation of ACL hamstring grafts were identified prospectively and retrospectively from our PACs database during a period from 9/1/08 to 8/31/09. All imaging was performed using 1.5 or 3.0 Tesla MRI and were evaluated for T2 signal within and surrounding the crosspin, osteolysis surrounding the fragments, displacement of fragments, and graft integrity. Time from surgery was also recorded.


RESULTS
Seven cases of hamstring grafts with broken bioabsorbable crosspins were imaged 4 months to 3 years following grafting. There was osteolysis surrounding the crosspin in all but one case in which the graft was intact but a pin fragment was displaced into the joint. One graft failed due to aseptic foreign-body reaction to the fixation with aggressive osteolysis at 9 months post surgery. In the remaining five, the ACL graft was either completely torn, partially torn, lax, or degenerative and frayed. Of these, the crosspins were broken and angulated with osteolysis surrounding the apex of the angulated fragment or demonstrated lateral extrusion of the peripheral fragment.


CONCLUSIONS
Bioabsorbable crosspins utilized in femoral fixation of hamstring graft reconstruction of the ACL may become fractured. While the natural history of osteo-integration of these devices as demonstrated by MRI has not been defined, osteolysis surrounding the fragments, extrusion or displacement of the fragments, and graft laxity or failure would suggest that these are abnormal findings that should be reported.
Department of Radiology Jacobi Medical Center, 1400 Pelham Parkway South, Bronx, NY 10461, USA. ptbakhru@gmail.com
Prashant
P
Bakhru
Brian
B
Park
Hilary
H
Umans
Gregory S
GS
DiFelice
Keith
K
Tobin
D020341:Absorbable Implants; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D001858:Bone Nails; D005269:Femur / Q000601:surgery; D005549:Foreign-Body Reaction / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000637:transplantation*; D010014:Osteolysis / Q000175:diagnosis*; D011446:Prospective Studies; D011475:Prosthesis Failure; D019651:Plastic Surgery Procedures / Q000379:methods*; D012189:Retrospective Studies