The Clinical Study Of The Relationship Between Allograft Diameter And Joint Stability After Anterior Cruciate Ligament Reconstruction

Objectives: Anterior cruciate ligament(ACL) injury is getting more popular with the development of modern traffics and sports. ACL injury impairs joint stability and induces traumatic arthritis. By now arthroscopic assisted ACL reconstruction is accepted as the most widely accepted treatment of ACL injury. The most widely used grafts includes autograft, allograft, etc. The ultimate loads of semitendinosus and gracillis tendon are 1483N±332N å'Œ889N±206N respectively. However, the autografts harvested in the surgery are affected by factors such as the surgeons’ technique, the patients’ body weight, height, etc. In a clinical study of ACL reconstruction with autografts, researchers have found that there is positive correlation between the graft diameter and joint stability. In a study there is no surgical failure or renovation if the autograft diameter is beyond 8mm. although factors as patients’ height and examination as MRI helps in prediction of autograft diameter, there is still limited means in predicting autograft length and diameter. In this study, we retrospectively studied 120 patients who undertook ACL reconstruction with allograft. The relationship between the allograft diameter and joint stability, symptom, everyday function and were studied.Method:(1) This study was performed in the 3rd hospital of Hebei Medical University.(2) A total of 120 patients who received arthroscopic assisted ACL reconstruction with allograft between 2010 and 2012 were enrolled. Male 53 cases, female 67 cases. Age: 16-51(average 31.1). 27 cases were by traffic accidence, 39 cases were sports injury. Type: 36 cases were ACL injury and 84 cases were ACL and meniscus injury.(3) Diagnosis: all patients received physically exam and joint MRI scan and clinically diagnosed as ACL injury under arthroscope.(4) Inclusion criteria: All the patients were diagnosed as ACL injury under arthroscope with/without meniscus injury. The surgery was performed by the same surgeon with the same type of fixation. The patients received the same rehabiliation protocol and signed a consent form of treatment.(5) Exclusion criteria: Patients of ACL partial injury, avulsion fracture, multi-ligament injury were excluded from this study.(6) Patients(n=120) were assigned by the allograft diameter in the operation to 5 groups: 7.5mm(n=10), 8.0mm(n=29), 8.5mm(n=35), 9.0mm(n=34) and 9.5mm(n=12).(7) Operation procedure: All operation were performed by the same senior surgeon. Patients’ ACL ligament was carefully checked in the operation with a Stryker arthroscope system. Two deep frozen hippicus muscle tendon was recovered, then were folded into two layers and shaped like a tube using method like baseball stitch with No.2 Ethibond sutures. The diameter of the graft was measured as between 7.0-9.5mm. The tibial tunnel was placed at the center of ACL footprint, the femoral tunnel was located in the direction of 10 o’clock for the right knee(and in the direction of two o’clock for the left knee). A transtibial technique was used for all the operations. Endobutton system was used in femoral side fixation. The knee was flexed at 30 degree, the graft was tensioned and bioabsorbable interface screw was used to fix the graft in the tibial side tunnel. The knee was extended and impingement between graft and intercondylar notch was checked under arthroscope. A standard accelerated ACL rehabilitation protocol was used for all patients. Patients returned to sports at 6 months after operation.(8) Study subjective: all the patients undertake follow-up evaluation at 2 years after surgery. Joint stability was evaluated by KT-1000 device(MED metric, United States) and the values were recorded. The stability between the operated joint the contra-lateral side was divided as 4 grades: Grade A(<3mm, normal), Grade B(3-5mm, close to normal), Grade C(5-10 mm, mild abnormal) and Grade D(>10mm, severe abnormal). The patient number in each group were recorded. Moreover, all the patients received subjective evaluation by international knee documentation committee(IKDC) score. The difference of KT-1000 and IKDC score between each group was compared by chi-square test and t-test. P<0.05 was accepted as statistically different.Results: KT-1000 evaluation: At 2 years after surgery, 68 patients are grade A(56.7%), in which 4 patients’ allograft was 7.5mm, 12 patients’ allograft was 8.0mm, 19 patients’ was 8.5mm, 23 patients’ were 9.0mm and 10 patients’ were 9.5mm. 47 patients are grade B(39.1%), in which 3 patients’ allograft was 7.5mm, 15 patients’ allograft was 8.0mm, 16 patients’ was 8.5mm, 11 patients’ was 9.0mm and 2 patients’ was 9.5mm. 2 patients are grade C(1.7%), one patients’ allograft was 7.5mm and the other one was 8.0mm. 3 patients are grade D(2.5%), 2 patients were 7.5mm and the other one was 8.0mm. IKDC evaluation: the total score of the 120 patients was 76.00±7.77,patients of 7.5mm allograft was 69.00±6.57, patients of 8.0mm allograft was 70.97±5.97, patients of 8.5mm allograft was 76.91±6.86, patients of 9.0mm allograft was 79.76±7.01, patients of 9.5mm allograft was 80.75±7.25.Conclusion: In ACL ligament reconstruction with allograft, at 2 years post operation, joint KT-1000 and IKDC scores increase with the increase of allograft diameter, which indicates allograft with larger diameter provides better joint stability and function.