The assessment of extensor mechanism in knee arthroplasty patients whom applied quadriceps snip or quadriceps turndown

One of the difficulties faced during revision knee prosthesis is arthrotomy. Therefore, extended approaches are frequently applied in order to reach the articular. For this purpose, quadriceps snip and V-Y quadricepsplasty are the frequently used methods. However, some authors believe that extensor mechanism and patella circulation will be negatively affected in the cases where V-Y quadricepsplasty is applied, and therefore they do not recommend this method. In the literature, the publications researching the effects of extended approaches on the extensor mechanism of the knee after the surgery are limited and contradictive. Therefore, in our study, we aim to research the effects of quadriceps snip and V-Y quadricepsplasty on extensor mechanism after the surgery. We are included in the study 92 knees which were operated by using quadriceps snip and V-Y quadricepsplasty techniques between 2006 and 2014 years. The group on which quadriceps snip was applied consists of 37 patients and the group on which quadricepsplasty was applied consists of 55 patients. Patients' demographic data (age, sex) and information related to surgery (incision type, year of surgery, operated extremity, number of operations applied, and starting week of flexion) were evaluated retrospectively. Besides, by using universal transparent goniometer, extensor restriction, varus-valgus deformities, knee flexion angles, instability existence, flexor and extensor muscular forces (with hand-held dynamometer) of the patients and by HSS (Hospital for Special Surgery) and LEFS (Lower Extremity Functional Scale) scores, functional condition of the knee and activity levels of the patients were evaluated cross-sectionally. Demographic data (age: 67y/ 71y) (sex ( W/M): 31/6; 42/13 ) and data related to surgery (incision type, year of surgery, operated extremity, number of operations applied) between both groups were detected similar (p>0.05). However, quadriceps snip group started knee flexion movement earlier after the surgery and statistically significant difference was found between two groups (p=0.00). Statistically significant difference was not found regarding extensor restriction, varus-valgus deformities, knee flexion angles, instability existence, flexor and extensor muscular forces, and HSS (Hospital for Special Surgery) and LEFS (Lower Extremity Functional Scale) scores (p>0.05). Moreover, extensor mechanism difference among the patients whose one knee or both knees were operated was evaluated. Prosthesis for both knees was applied to 25 patients out of sixty seven. Statistically significant difference was not found considering the age, sex, starting week of flexion, extension restriction, year of operation and deformity parameters of the groups we formed (p>0,05). Statistically significant difference was not found in the measurement of extensor mechanism muscular force and hamstring muscular force (p>0,05). Moreover, the effects of starting time of physical therapy of the patients on functional outcomes were evaluated. No difference was found between knee flexion patency and extensor mechanism force regarding the patients whose physical therapy was started in the early or late period after V-Y quadricepsplasty. When the results are taken into consideration, V-Y quadricepsplasty is a preferable method since it allows a wider arthrotomy for tough knees and knee revision surgery, and provides an easier operation. Choosing this incision does not bring disadvantage in terms of extensor mechanism. Furthermore, it was detected that operating one knee or both does not create a different effect on the extensor mechanism.