Purpose of the study: Conservative surgical treatment of osteochondritis dissecans (OCD) in adults raises the problem of integration of the sequestered bone. Mechanical techniques using screw fixation are often insufficient to achieve healing. Adjunction of a biological fixation with osteochondral graft tissue for a mosaicplasty might favour integration of the fragment. The purpose of this study was to assess the short-term outcomes in an initial series using a technique called fixation plus where screw fixation is associated with mosaiplasty.

Material and methods: This was a retrospective analysis of eight adults who underwent surgery from 2003 to 2008 for stage IIB or III (Bedouelle) OCD of the medial condyle. Loss of subchondral tissue could be filled with a cancellous graft. Clinical and radiographic (Hugston) parameters were noted. At three months, the screws were removed arthroscopically. The ICRS-OCD score was noted. At six months, five patients had an arthroMRI to evaluate fragment integration, determine its signal and vitality.

Results: Mean follow-up was 17.4 months (range 3–36). The Hugston score improved from 1.6 (0–3) preoperatively to 3.4 (2–4) postoperatively and the radiological score from 2.5 (2–4) to 3.2 (3–4). The arthroscopy performed to remove the screws revealed integration of the OCD fragment. The ICRS-OCD score was I in two cases, II in five and III in one. The postoperative arthroMRI confirmed continuity with the cartilage at the periphery of the fragment, with no passage of contrast agent into the defect.

Discussion: Screw fixation of OCD fragments is often followed by nonunion and thus failure. Moasaicplasty is an alternative but does not preserve quality cartilage cover (curvature, thickness, cover). The technique proposed here ensures osseous integration of he fragment, complete cartilage cover, and a smaller number of osteochondral pits. Fixation Plus associates mechanical and biological fixation with good preliminary clinical results. Comparative longer term assessment is needed to confirm its pertinence.