Unikompartimentelle Oxford-III-Prothese mit mobilem Gleitlager

The Interaction of Caseload and Usage in Determining Outcomes of Unicompartmental Knee Arthroplasty: A Meta-Analysis

BACKGROUND

Outcomes after unicompartmental knee arthroplasty (UKA) are variable and influenced by caseload (UKA/y) and usage (percentage of knee arthroplasty that are UKA), which relates to indications. This meta-analysis assesses the relative importance of these factors.

METHODS

MEDLINE (Ovid), Embase (Ovid), and Web of Science (ISI) were searched for consecutive series of cemented Phase 3 Oxford medial UKA. The primary outcome was revision rate/100 observed component years (% pa) with subgroup analysis based on caseload and usage.

RESULTS

Forty-six studies (12,520 knees) with an annual revision-rate ranging from 0% to 4.35% pa, mean 1.21% pa (95% confidence interval [CI], 0.97-1.47), were identified. In series with mean follow-up of 10-years, the revision-rate was 0.63% pa (95% CI, 0.46-0.83), equating to a 94% (95% CI, 92%-95%) 10-year survival. Aseptic loosening, lateral arthritis, bearing dislocation, and unexplained pain were the predominant failure mechanisms with revision for patellofemoral problems and polyethylene wear exceedingly rare. The lowest revision-rates were achieved with caseload >24 UKA/y (0.88% pa; 95% CI, 0.63-1.61) and usage >30% (0.69% pa; 95% CI, 0.50-0.90). Usage was more important than caseload; with high usage (≥20%), the revision-rate was low, whether the caseload was high (>12 UKA/y) or low (≤12 UKA/y; (0.94% pa; 95% CI, 0.69-1.23 and 0.85% pa; 95% CI, 0.65-1.08), respectively); with low usage (<20%), the revision-rate was high, whether the caseload was high or low (1.58% pa; 95% CI, 0.57-3.05 and 1.76% pa; 95% CI, 1.21-2.41, respectively).

CONCLUSION

To achieve optimum results, surgeons, whether high or low caseload, should adhere to the recommended indications such that ≥20%, or ideally >30% of their knee arthroplasties are UKA. If they do this, then they can expect to achieve results similar to those of the long-term series, which all had high usage (>20%) and an average 10-year survival of 94%.

Open wedge high tibial osteotomy (HTO) versus mobile bearing unicondylar medial joint replacement: five years results

INTRODUCTION

Aim of this study was to compare clinical results after open wedge HTO (OW-HTO and medial unicondylar joint replacement (UKA) in patients aged between 55 and 65.

MATERIALS AND METHODS

Fifty-four patients aged between 55 and 65 years with medial OA and varus malalignement who had been treated by either OW-HTO or UKA could be included. Minimum follow up was 5 years. The HSS knee score and the KOOS were used to evaluate clinical outcome.

RESULTS

There was no difference in the revision rate, the HSS knee score and the KOOS subscales Sports/Rec and ADL between the OW-HTO and UKA group. However, the KOOS subscales pain, Symptoms and QoL were significantly better in the UKA group compared to the OW-HTO.

CONCLUSIONS

The results of this study showed that 5 years after surgery patients after UKA had less residual pain and symptoms than patients after UKA. These advantages might result in a higher quality of life.