Press-fit stability of an osteochondral autograft: Influence of different plug length and perfect depth alignment.
BACKGROUND
Osteochondral autologous transplantation is used for the treatment of full-thickness articular cartilage lesions of a joint. Press-fit stability is an important factor for good survival of the transplanted plugs.


METHODS
36 plugs of three different lengths were transplanted in fresh-frozen human knees. On one condyle, 3 plugs were exactly matched to the depth of the recipient site ("bottomed" plugs) and on the opposite condyle 3 plugs were 5 mm shorter than the depth of the recipient site ("unbottomed" plugs). Plugs were left protruding and then pushed in until flush, and then to 2 mm below flush level, using a loading apparatus.


RESULTS
Longer plugs needed higher forces to begin displacement. At flush level, bottomed plugs needed significantly higher forces than unbottomed plugs to become displaced below flush level (mean forces of 404 N and 131 N, respectively). Shorter bottomed plugs required higher forces than longer bottomed ones.


CONCLUSIONS
Bottomed plugs generally provide much more stability than unbottomed ones. Short bottomed plugs are more stable than long bottomed plugs. Thus, in clinical practice it is advisable to use short bottomed plugs. If, however, unbottomed plugs are still chosen, the longer the plug the higher the resulting stability will be because of higher frictional forces.
Kock
Niels B
NB
Orthopaedic Research Laboratory, Department of Orthopaedics, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Van Susante
Job L C
JL
Buma
Pieter
P
Van Kampen
Albert
A
Verdonschot
Nico
N
D001696:Biomechanical Phenomena; D016025:Bone Transplantation / Q000379:methods*; D002356:Cartilage / Q000637:transplantation*; D002358:Cartilage, Articular / Q000601:surgery; D019902:Chondrocytes / Q000637:transplantation*; D005269:Femur / Q000601:surgery / Q000637:transplantation; D006085:Graft Survival; D006801:Humans; D007719:Knee Joint / Q000601:surgery*