TREATMENT OF INSUFFICIENT JOINT EXTENSOR MECHANISM IN PRIMARY AND REVISION KNEE REPLACEMENT

Abstract

Insufficiency  of the  knee  joint  extensor  mechanism  is the  absolute  contraindication for total  knee  arthroplasty. Therefore, it is necessary to restore the extensor  mechanism before arthroplasty or to change the treatment approach.Purpose of the study  – to evaluate  the  outcomes  of surgical  reconstruction of the  knee joint  extensor  mechanism during primary or revision knee arthroplasty.Materials and methods. 25 reconstructions of extensor  mechanisms  (24 patients) were performed  in the period from 2006 to 2015. Five procedures out of 25 were performed in primary TKA and 20 in revision TKA. Indications for extensor mechanism  reconstruction were as follows: patellar  tendon  rupture in 15 cases (60,0%),  fracture  of patella  in 5 cases (20,0%), quadriceps tendon  rupture in 3 cases (12,0%) and other indications in 2 cases (8,0%). One of the following four techniques was used to restore  the extensor  mechanism: “Frame / Loop” allograft of patellar  tendon  in 6 cases (24,0%); bone – patellar  tendon  – bone allograft in 9 cases (36,0%); quadriceps tendon  – patella-patellar tendon  – bone allografts in 7 cases (28,0%); weber’s internal fixation of patella in 3 cases (12,0%).Results.  All patients were  evaluated based  on  clinical  examination,  KSS  and  WOMAC  scores  (18  patients), and standard x-rays (13 patients). The mean follow-up  period  in the  present  study  was 44 months  postoperatively. Reconstruction of the knee joint extensor  mechanism  resulted  in a significant  reduction of pain in 38.8% of patients, the knee stability was restored  in 83,3% of patients and the active  knee extension  improved  significantly  in the vast majority  of patients.Conclusion. Despite  the  objective  improvement of the  knee  joint  function  after  the  reconstructions of extensor mechanism,  the  KSS and WOMAC evaluation scores remained  low which  should  be taken  into  consideration during preoperative planning.