Ligamentoplasty resorting to autogenous bone-tendon-bone grafts represents an effective long-lasting remedy to the anterior instability of the knee. If this indication has proved effective regarding the stability, the sampling of a piece of the extensor system often brings about a certain morbidity. Various approaches have been advocated concerning the tendinous site: some leave it open, others suture one of the peripheral thirds of the remaining tendon to the other. These various technical choices are likely to alter the morbidity and the patellar level, together with the tissue nature of the site of sampling. The purpose of this study was to assess the effect of the suture of the site of sampling on the patellar level, after a ligament plastic surgery resorting to a bone-tendon-bone graft. To this end, a group of 40 patients whose tendinous site of sampling had been left open was compared to another group of patients whose peripheral thirds of the remaining patellar tendon had been sutured one to the other. The patellar level was assessed with Caton’s, Black-burne’s and Insall and Salvati’s methods on x-rays first taken before and then 6 months after the operation. To analyse the results, we resorted to the reduced gap method and the Student-Fisher one for the comparison between quantitative and qualitative variables, and to the correlation coefficient method for the comparison between quantitative variables. The post-operative values of Caton’s, Blackburne’s and Insall and Salvati’s indexes were respectively 1.002, 0.844, and 1.188 for patients whose patellar tendon had been left open, and 1.023, 0.882, and 1.184 for patients whose tendinous edges had been sutured up. The discrepancy between those values had no statistical significance. Suturing the site of sampling in a bone-tendon-bone ligament plastic surgery has no effect on the patellar level.