Long-Term Clinical and MRI Results after Refixation of osteochondral Fractures with resorbable Implants

AIMS AND OBJECTIVES: Refixation with resorbable implants is a common surgical treatment in patients with an osteochondral fracture of the knee or the upper ankle joint. Up to date there are no studies, which outline long-term outcome of this procedure. As a consequence aim of this study was to evaluate the long-term clinical und MRI results. MATERIALS AND METHODS: In this study 12 patients were examined 13,9 (#CHR: plusmn# 1,2) years after refixation of an osteochondral fragment of the knee (10) and the upper ankle joint (2) with a mean size of 3.16 cm² (#CHR: plusmn# 2,27) by resorbable implants (SmartNail, Conmed). We used eight established clinical scores (VASS, Tegner, Lysholm, McDermott, KSS, WOMAC, AOFAS, FADI+Sports). Furthermore we ascertained integration of bone and cartilage morpholgy by MRI (3 Tesla) using proton-weighted- and cartilage-sensitive double-echo-steady-state (DESS) sequences. To identify a possible osteonecrosis we used T1-weighted sequences with a contrast agent (Gadolinum). The morphologic results were objectified with a modified MRI-Score based on Henderson et al. (2003). RESULTS: After 13,9 (#CHR: plusmn# 1,2) years the patients with an injury of the knee as well as of the upper ankle joint showed good to excellent results (Knee: VASS: 1,3 (#CHR: plusmn# 1,7); Tegener 4,4 (#CHR: plusmn# 1,3); Lysholm 85,7 (#CHR: plusmn# 12,2); McDermott 90,7 (#CHR: plusmn# 8,6); KSS 189 (#CHR: plusmn# 15,9); WOMAC (6,16% (#CHR: plusmn# 8,45)) (Upper Ankle joint: VASS: 2,5 (#CHR: plusmn# 2,5); Tegener 5,5 (#CHR: plusmn# 1,5); Lysholm 87 (#CHR: plusmn# 13), McDermott 88 (#CHR: plusmn# 12); WOMAC (8,54% (#CHR: plusmn# 8,54); AOFAS 75,5 (#CHR: plusmn# 24,5); FADI+Sports 118 (#CHR: plusmn# 18)). There was a good integration of the osteochondral fragment in all cases in the MRI. 5 patients showed moderate subchondral cysts. There were changes of the cartilage contour in all patients. The mean Henderson-Score was 14,4 (#CHR: plusmn# 2,0) (Best: 8, Worst: 32), which correlates with good results. CONCLUSION: Because of its good clinical and MRI results the refixation by resorbable implants can be recommended to treat osteochondral flakes.