Published online Sep 18, 2018. doi: 10.5312/wjo.v9.i9.149
Peer-review started: March 2, 2018
First decision: March 18, 2018
Revised: July 3, 2018
Accepted: July 14, 2018
Article in press: July 15, 2018
Published online: September 18, 2018
Postoperative genu recurvatum (GR) has a tendency to develop in the medial osteoarthritis (OA) knee with preexisting GR following total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA). The prosthesis of choice for medial OA knee with preexisting GR is controversial. Constrained TKA has been chosen by some surgeons for prevention of postoperative GR, even though the patients could develop early loosening of the prosthesis, require early reoperation, and experience bone loss during revision TKA. The present study found that the medial OA knee with preoperative GR (< 19°) and without preoperative GR have similar clinical outcomes and determined the incidence of postoperative GR following mobile bearing UKA. Use of the normal biomechanic and kinematic parameters, while adjusting some steps of the surgical technique, including a tighter extension gap with and without application of larger femoral component, could prevent postoperative GR following mobile bearing UKA.
Medial OA knees with and without preexisting GR have shown good clinical outcomes and no difference in incidence of postoperative GR following mobile bearing UKA. However, the causes of OA knee with preexisting GR are unclear. Quadricep muscle weakness from spondylosis or abnormal ligament tension might underlie the occurrence of OA knee with preexisting GR. Therefore, the future research should focus on this yet unresolved issue.
The main objectives of this study were to determine the clinical outcomes and the incidence of postoperative GR in medial OA knees with and without preexisting GR.
In this prospective cohort study, we used pain score, functional score and knee score to compare patients having medial OA knees with and without preexisting GR. The occurrence of postoperative GR and hyperextension angle were also recorded. Follow-up extended from 24 mo to 70 mo, for a mean of 37.66 mo. No patients were lost to follow-up.
Medial OA knees with and without preexisting GR showed similar clinical outcomes and incidence of postoperative GR following mobile bearing UKA. The mean Knee Society Score© was 97.97 for patients with preexisting GR and 96.91 for patients without GR. The incidences of postoperative GR were 3.13% and 0.7% for patients with preexisting GR and patients without preexisting GR, respectively.
Medial OA knee with preoperative GR is not a contraindication for mobile bearing UKA.
Mobile bearing UKA with a little tight extension gap with and without use of a larger femoral component could prevent postoperative GR in the medial OA knee with preexisting GR. However, the causes of GR in OA knee patients without neuromuscular disorder remain unclear and should be identified by future studies.