Knee Surg Relat Res.  2018 Sep;30(3):234-240. 10.5792/ksrr.17.085.

Redislocation after Bearing Exchange for the Treatment of Mobile Bearing Dislocation in Medial Unicompartmental Knee Arthroplasty

• Kim SG
• Kim HG
• Lee SY
• Lim HC
• Bae JH

• KMID: 2420349
• DOI: http://doi.org/10.5792/ksrr.17.085

Abstract

PURPOSE
This study was conducted to investigate the outcomes of bearing exchange for the treatment of mobile bearing dislocation in medial unicompartmental knee arthroplasty (UKA).
MATERIALS AND METHODS
We retrospectively reviewed 18 patients (15 females and 3 males, mean age of 65 years) treated with bearing exchange following mobile bearing dislocation in medial UKA. The occurrence of bearing redislocation, the Oxford Knee Score, and radiographic changes at the last follow-up were investigated.
RESULTS
Bearing redislocation after bearing exchange occurred in 9 of 18 patients (50%). Of these 9 patients, 7 underwent conversion to total knee arthroplasty after bearing redislocation. The 9 patients without bearing redislocation showed good to excellent clinical outcomes at a mean follow-up of 55 months after bearing exchange. The non-redislocation group had a higher percentage of posterior dislocation of the bearing than the redislocation group (55.5% vs. 22.2%, p=0.040). Univariate logistic regression analysis showed no significant risk factors for bearing redislocation.
CONCLUSIONS
This study showed a high rate of bearing redislocation after isolated, mobile bearing exchange for bearing dislocation following medial UKA. Therefore, bearing exchange as a sole treatment should be carefully considered in selected patients with correctable causes of bearing dislocation.

Keyword

Knee; Arthroplasty; Unicompartmental; Dislocation

MeSH Terms

Arthroplasty
Arthroplasty, Replacement, Knee*
Dislocations*
Female
Follow-Up Studies
Humans
Knee
Logistic Models
Male
Retrospective Studies
Risk Factors