ABSTRACT
Ligament graft fixation with bioabsorbable interference screws is a standard procedure in cruciate ligament replacement. Previous screw designs may resorb incompletely, and can cause osteolysis and sterile cysts despite being implanted for several years. The aim of this study was to examine the in vivo degradation and biocompatibility of the new Milagro interference screw (Mitek, Norderstedt, Germany). The Milagro interference screw is made of 30% ss-TCP (TriCalcium phosphate) and 70% PLGA (Poly-lactic-co-glycolic acid). In the period between June 2005 and February 2006, 38 patients underwent graft fixation with Milagro screws in our hospital. Arthroscopic ACL reconstruction was performed using hamstring tendon grafts in all the patients. MR imaging was performed on 12 randomly selected patients out of the total of 38 at 3, 6 and 12 months after surgery. During the examination, the volume loss of the screw, tunnel enlargement, presence of osteolysis, fluid lines, edema and postoperative screw replacement by bone tissue were evaluated. There was no edema or signs of inflammation around the bone tunnels. At 3, 6 and 12 months, the tibial screws showed an average volume loss of 0, 8.1% (+/-7.9%) and 82.6% (+/-17.2%, P < 0.05), respectively. The femoral screws showed volume losses of 2.5% (+/-2.1%), 31.3% (+/-21.6%) and 92.02% (+/-6.3%, P < 0.05), respectively. The femoral tunnel enlargement was 47.4% (+/-43.8%) of the original bone tunnel volume after 12 months, and the mean tunnel volume of the tibial tunnel was -9.5% (+/-58.1%) compared to the original tunnel. Bone ingrowth was observed in all the patients. In conclusion, the resorption behaviour of the Milagro screw is closely linked to the graft healing process. The screws were rapidly resorbed after 6 months and, at 12 months, only the screw remnants were detectable. Moreover, the Milagro screw is biocompatible and osteoconductive, promoting bone ingrowth during resorption. Tunnel enlargement is not prevented in the first months but is reduced by bone ingrowth after 12 months.
ABSTRACT
BACKGROUND: A review of recent reports concerning the functional outcome after treatment for Cyclops syndrome can produce contradictory results. Therefore, the purpose of this study was to evaluate the functional outcome of our patients treated for Cyclops syndrome after anterior cruciate ligament reconstruction. METHODS: Between 1998 and 2006 ten patients were followed for the occurrence of a Cyclops syndrome. The Lysholm score, Marshall score and Tegner activity score was used for clinical evaluation at final follow up; in addition, a subjective assessment of knee function and knee pain on a visual analogue scale was registered. Knee stability was measured using the KT-1000 arthrometer. Results were compared with a control group of 24 uneventful ACL reconstructions. RESULTS: Revision arthroscopy for symptomatic extension block was performed after a mean of 6.8 months. After a mean follow-up of 23 months after second surgery all patients' regained full range of motion. The mean Lysholm score and Marshall score was 85 and 41 after Cyclops syndrome and 92 and 46 for the control group. After Cyclops syndrome patients experienced a significantly increased ACL transplant laxity but no significant difference was found concerning patient's subjective rating of knee function and knee pain. CONCLUSION: Although patients subjective rating of knee function and knee pain was nearly identical in both groups objective knee scores disclosed impaired knee function in our patients treated for Cyclops syndrome.
