Press-fit stability of an osteochondral autograft: Influence of different plug length and perfect depth alignment

Abstract

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.Material and 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.Interpretation 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.

Topographic Analysis of the Capitellum and Distal Femoral Condyle: Finding the Best Match for Treating Osteochondral Defects of the Humeral Capitellum

“…However, histologic evidence shows that healing and integration of host and graft occur at the subchondral bone level as opposed to the cartilage level. 6 Thus restoring the anatomic bony contour is critical to optimize transplant integration and potentially to improve the short-and long-term results of this procedure. Similar technology has been used to evaluate the proximal medial tibia and distal lateral tibia to allow for accurate allograft harvesting for glenoid deficiencies with good success.…”

“…The donor plugs are pressfitted into the lesion to restore the surface topography and to provide subchondral replacement in the defect. 6 One difficult aspect of this procedure is ascertaining where the optimal graft harvest site is located. Most frequently, grafts are harvested from the periphery of the femoral condyle, at the level of the patellofemoral joint, away from the weight-bearing surfaces, and more specifically, the superolateral aspect of the lateral femoral condyle, as well as the intercondylar notch, has been described.…”

The effect of tissue-engineered cartilage biomechanical and biochemical properties on its post-implantation mechanical behavior

“…Small diameter implants are less susceptible to damaging strains; yet, they are less stable. This may increase the chance of implant failure (Kock et al 2006;Hurtig et al 1999). Indeed, in clinical practice, treatment depends on defect size.…”

“…The bigger the implant's dimensions, the larger the contact area between implant and surrounding subchondral bone. Because of more friction, higher forces are needed to displace an implant; thus, the implant is more stable (Kock et al 2006;Duchow et al 2000). Small diameter implants are less susceptible to damaging strains; yet, they are less stable.…”

“…Small defects are normally treated by microfracturing or abrasion, rather than transplantation. Accordingly, the implant diameter that we have considered in our study is chosen to be clinically relevant (Kock et al 2006).…”