Purpose of the study: Grafting the anterior cruciate ligament with a bone-tendon-bone free transplant injures the harvesting site, causing sensorial disorders by injuring the infrapatellar nerve in 70% of the cases. Mini-invasive techniques can limit these complications. The purpose of this work was to analyse the feasibility of a mini-invasive technique using a single incision.

Material and methods: A prospective comparative study was conducted in our unit to compare a group of “classical” harvesting via an anteromedial incision and a “mini-invasive” technique using a incision centred on the patella with the graft being harvested with a specially designed harvesting instrument. Each group was composed of 20 patients. The patients were reviewed six to eight months postoperatively. Clinical assessment (IKDC, Lillois score, analysis of sensorial impairment) was associated with the radiographic and ultrasound analysis. Radiographic laxity was assessed on the stress views at 15 kg. The ultrasound study analysed the patellar tendon and the peritendon. Significance for statistical tests was set at 0.05 with correlation coefficients (R) determined with a covariance matrix ½ Log([1 + R]/[1−R]).

Results: The grafts harvested by the classical method presented good characteristics in all cases whereas this was true for only 45% of the mini-invasive grafts. Anterior pain was noted in 22% of patients in the classical group and in 33 of the mini-invasive group. There was no correlation between anterior knee pain and knee walking or thickness of the peritendon. A correlation was found between knee walking and asymmetry of the patellar tendon thickness in the mini-invasive group. The subjective IKDC score was the same in the two groups and the IKDC objective score was not significantly different (94% (A or B) in the classic group and 81% (A or B) in the mini-invasive group.

Conclusion: This mini-invasive technique with a single incision respects the infrapatellar branches of the medial saphenous nerve in 95% of the cases. But the quality of the graft is less satisfactory than with the classical harvesting technique. A correlation was found between the form of the anterior tibial tubercle which could be used to better define the ideal indication for this technique which remains a difficult procedure.

Purpose of the study: The form of the anterior tibial tuberosity (ATT) has not been described in anatomy studies. Insertion of the patellar tendon can, by its form, modify the lever arm of the extensor system and induce pathological conditions having an impact on the form of the apex or tip of the patella. The purpose of this work was to analyse the types of tibial tuberosities observed on the radiographs of 50 patients.

Material and method: Fifty patients were included in this prospective study. The form of the ATT was defined by two angles. These angles were measured on the strictly lateral x-ray. The ATT-shaft angle (ATT-d) was defined by the intersection between the anatomic axis of the tibial diaphysis and the anterior cortical of the ATT which corresponds to the insertion of the patellar tendon. The ATT-metaphysis angle (ATT-M) was defined by the angle between the tangents of the anterior metaphyseal cortical and the anterior cortical of the ATT. The height of the patella was also measured as described by Caton and Deschamps. The form of the patella on the lateral was described according to the Grelsamer criteria, and its form on the 30° axial view according to the Wiberg classification. The presence of trochelar dyplasia was determined using the Dejour method. The statistical analysis accepted p < 0.05 as significant. The coefficients of correlation R were calculated with a ½ log covariance matrix [1+R]/[1−R].

Results: The form of the ATT was given by the minimal value between the ATT-D and the ATT-M. This angle measurement revealed major variation. Three types of ATT were defined: type I 0≤ATT-M≤15 and ATT-D≤5, type II 15 < ATT-M < 20 and 5 < ATT-D < 10 and type III 20≤ATT-M 10≤ATT-D. There was an obvious correlation with the form of the patellar apex. The type III form of the patella was always associated with a type I ATT; there was a significantly association between patella type I and ATT type II and patella type III and ATT type I. There was no correlation with the height of the patella or with the form of the trochlea or the patella.

Conclusion: The form of the ATT is quantifiable and becomes a parameter to consider in the analysis of patellofemoral osteoarthritis.