The “Apple-Bite-Fracture”: ACL rupture combined with posterolateral tibia plateau fracture

摘要

Aims and Objectives: Anterior cruciate ligament (ACL) ruptures are often concomitated by posterolateral bone bruise in the MRI. This is caused by a ventral subluxation of the tibia and impact of the femur in the posterolateral tibia plateau. In some cases, this impact causes a fracture of the posterolateral tibia plateau, the so-called Apple-Bite-Fracture. The increased posterior slope can cause additional instability and has to be considered as a risk factor for ACL failure. In this study we investigated the short term clinical outcomes of patients with this combined injury. Materials and Methods: Retrospective study of 14 patients (mean age 46 ± 12,3) (8 male, 6 female) with a mean follow up of 23,75 months. Different treatment strategies were analyzed. The clinical evaluation included visual analog score (VAS) increasing from 0-10 for Pain, IKDC Score, Rasmussen score as well as a clinical evaluation. Results: First analysis of the treatment options revealed a non-uniformed therapy strategy. In three patients the ACL tear was treated nonsurgical. In 11 patients the ACL tear was addressed surgical: six times the ACL was reconstructed with hamstring tendon graft, two times the ACL was sutured. Two patients treated with a non-reconstructive technique to promote healing (“healing response”). In one patient a tibial eminence fracture was fixated with a screw. The fracture of the posterolateral tibia plateau was in nine cases minimally invasive reduced and fixated with a screw osteosynthesis in jail technique. Two patients needed posterior buttress plate. Three times the large bone defect has been augmented with autologous bone graft from the pelvis. The postoperative clinical testing did not reveal any persisting knee instabilities. All patient had a non-limited ROM. No significant differences in ROM in comparison to the contralateral knee was seen. One patient reported persisting knee pain (VAS 3). All other patients reported no pain (VAS 0). Subjective IKDC score was 78,18 (71,3 - 83,9; ± 5,68). Clinical Rasmussen scores ranged from 27 to 30 (mean 27, ± 3,0). Rasmussen radiological results ranged from 16 to 18, mean 16,67 (± 1,15). Conclusion: Despite a very small patient number and leck of statistical power the new patient-spedific mini-metal implant seems to be a good options fort he treatment of middle-aged patients who already underwent frustane cartilage surgery. In these relatively rare caes early unicompartimental arthroplasty can be prevented. Further clinical studies with larger patient collectives have to prove the effectiveness of this new technique.