Use of all-polyethylene tibial components in unicompartmental knee arthroplasty increases the risk of early failure

AbstractAll-polyethylene (all-poly) tibial designs in primary total knee arthroplasty (TKA) have been reconsidered with excellent clinical outcomes, survivorship, and cost-effectiveness. However, whether all-poly tibial components provided comparable results to metal-backed modular components during unicompartmental knee arthroplasty (UKA) remains unclear. This study compared the clinical outcomes and prevalence of early failure between all-poly and metal-backed modular components in UKA. We retrospectively reviewed the records and radiographs of 101 consecutive UKAs. In total, 51 UKAs were performed using all-poly tibial components; 50 others used metal-backed modular components. Clinical and radiographic outcomes, adaptive bone remodeling assessed by radiographic bone density, and early failure prevalence rates were compared. Despite a lack of group differences in clinical and radiographic outcomes (p > 0.1 in all comparisons), adaptive bone remodeling at 2 years after surgery of all-poly UKAs was more progressive compared with metal-backed UKAs (1.2 in all-poly UKA group vs. 0.9 in metal-backed UKA group, p < 0.001). In addition, 6 of 51 all-poly UKAs failed within 2 years postoperatively, whereas no metal-backed UKAs failed (11% in all-poly UKA group vs. 0% in metal-backed UKA group, p = 0.027). All-poly tibial component use during UKA increased the risk of early failure, which may be due to a failure in tibial loading distribution.

Download Full-text

Does obesity influence early outcome of fixed-bearing unicompartmental knee arthroplasty?

Journal of Orthopaedic Surgery ◽

10.1177/2309499016684297 ◽

2017 ◽

Vol 25 (1) ◽

pp. 230949901668429 ◽

Cited By ~ 11

Author(s):

Yew Lok Woo ◽

Yong Qiang Jerry Chen ◽

Mun Chun Lai ◽

Kheng Jin Darren Tay ◽

Shi-Lu Chia ◽

...

Keyword(s):

Functional Outcome ◽

Knee Arthroplasty ◽

Unicompartmental Knee Arthroplasty ◽

Short Form ◽

Functional Score ◽

Fixed Bearing ◽

Early Failure ◽

Early Outcome ◽

Unicompartmental Knee ◽

Significant Difference

Obesity is a known major contributing risk factor for knee osteoarthritis (OA). It is also believed that obese unicompartmental knee arthroplasty (UKA) patients tend to have poorer outcome and possible early failure. The purpose of this study is to investigate the early outcome of obese UKA patients in a single institution. Patients who underwent fixed bearing medial UKA in between year 2005 and 2010 were included in this study. They were divided into four groups based on Body Mass Index (BMI): 25 kg/m2 (Control); 25–29.9 kg/m2 (Overweight); 30–34.9 kg/m2 (Obese); >35 kg/m2 (Severely Obese). Functional outcome was assessed using Knee Society Score (KSS), Oxford Knee Score (OKS) and Short-form 36 (SF-36). One-way ANOVA with Bonferroni post-hoc test was used to compare the four groups for quantitative variables. There were 673 patients in this study, no significant difference between the four BMI groups for gender and side of operated knee ( p > 0.05). The functional outcome of all four groups at 2 years were comparable (all p > 0.05). At a mean follow up of 5.4 (range 2.5, 8.5) years, 9 revision surgeries (1.3%) were identified. The mean duration from initial surgery to revision surgery was 49 months (Range 6, 90). Patients’ pre-operative BMI did not influence the early outcome of UKA patients. However, patients with higher BMI had relatively lower functional score prior to the surgery and tended to be younger. This did not translate to early failure and the functional improvement was similar among all four groups.

Download Full-text