Radiographic and Clinical Evolution of the Oxford Unicompartmental Knee Arthroplasty

Abstract

The aim of the study is to evaluate whether the use of the new instrumentation Microplasty (MP) improves component positioning and the reliability of the surgical technique, reducing the implant outliers from the recommended range and providing a more accurate resection, while avoiding insufficient or excessive tibial resection and clinical scores. We prospectively analyzed clinical and radiographic outcomes of three consecutive cohorts for a total of 227 implants at a minimum follow-up of 36 months. The first cohort consisted of 67 Oxford unicompartmental knee arthroplasty (OUKA), using the phase III (Ph-III). The second cohort consisted of 136 OUKA, with the MP instrumentation. The third cohort consisted of 24 hypoallergenic OUKA, using the MP instrumentation (TiNbN). Postoperative alignment of the knee in the coronal and sagittal plane was measured using radiographs. No clinical differences were found among the three groups (p > 0.05). A significant difference was found on the slope between Ph-III and MP (p = 0.0005). Moreover, a significant difference was found in tibial angle and in tibial slope in arthroplasty with femoral size small (S), compared with size medium (M) or large (Ly) (tibia varus/valugs angle: p = 0.0484; tibial slope: p = 0.04). Similar results were found between small (AA, A, B) tibial size and large (C, D, E, F) tibial size for tibial varus/valgus (p = 0.03) angle and tibial slope (p = 0.003). A significant difference was found between Ph-III and MP in tibial slope in patients with body mass index (BMI) ≥25 kg/m2 (p = 0.0003). A positive correlation was noted between the femoral and tibial sizes and the tibial angle and the slope, and a negative correlation between weight and the tibial slope; furthermore, a positive correlation was found between Oxford knee score and radiographic angles. The MP instrumentation seems to be effective in determining the tibial cut and, particularly, improving the tibial slope, compared with Ph-III. The tibial slope is directly affected by the weight and measurements of the components, regardless of the instruments or the number of pegs, while clinical outcomes are correlated with implant position. This prospective comparative study reflects level of evidence II.

Enhanced recovery after surgery (ERAS) protocol in geriatric patients underwent unicompartmental knee arthroplasty: A retrospective cohort study

“…Although the optimal surgical treatment option for single-compartment KOA is still controversial, UKA has been proven to be successful. [ 13 – 15 ] UKA is characterized by better kinematic peculiarity and low pain scores; some studies demonstrated that UKA had lower complications than TKA in short-term outcomes. Considering the physical status and comorbidities, implanting a knee prosthesis in elderly patients possesses the characteristics of challenges and benefits, the clinical outcomes also argue in favor of UKA in elderly patients even aged >85 years.…”

Proximal fibular osteotomy relieves pain in spontaneous osteonecrosis of the knee: A retrospective study

“…Moreover, bone resection and implant positioning are crucial in UKAs and TKAs, and complicated surgical instruments are often required to assure correct positioning of the prosthesis. [ 17 ] The surgical procedures of PFO are relatively simple and leaves the intraarticular joint intact if future treatment is required.…”

Unicompartmental knee arthroplasty is superior to high tibial osteotomy for the treatment of medial unicompartmental osteoarthritis: A systematic review and meta-analysis

“…[ 4 ] However, for more serious medial unicompartmental knee OA (K–L grade II–IV), operations may obtain more ideal results. [ 5 , 6 ]…”

“…[ 15 ] Nevertheless, with improvements in operative techniques and the quality of the implants, UKA could also obtain a good response to its activity. [ 5 , 7 ] It is difficult for surgeons to decide which one is more suitable for patients with medial unicompartmental OA.…”