To evaluate prospectively the mid-term results of the Zimmer Unicondylar Knee arthoplasty (UKA). Between 2005 and 2012, 187 unicompartmental knee arthroplasties (UKA) were performed by a single surgeon using a fixed-bearing prosthesis (Zimmer). 37 cases were excluded as either were lost to follow-up or had less than six months follow-up. The study included 150 UKAs. Deformity, if present, was correctable. Patellofemoral joint (PFJ) disease was not considered as an absolute contraindication. The average patient age at the time of surgery was 66 years (range 42–88 years); 78 of which were male. Mean follow-up time was 3.6 years (range 7–81 months). Mean Body Mass Index (BMI) was 29 (range 21–41). Clinical and conventional radiological evaluations were carried out at six months, one, two and five years postoperatively. 147 cases were medial compartment replacement and three were lateral. 86 patients had grade III OA and 64 had grade IV (Kellgren and Lawrence). 113 patients had an element of PFJ disease. The mean Knee Society knee and function scores had an improvement from 55 and 54 points pre-operatively to 95 and 94 points respectively at time of most recent evaluation. The average flexion improved from 116 degrees pre-operatively to 127 degrees. Two cases were revised, one due to progression of osteoarthritis in the lateral compartment of the knee and the other was due to arthrofibrosis. The Zimmer unicompartmental knee arthroplasty provided excellent pain relief and restoration of function in carefully selected patients. However, long-term studies are necessary to investigate the survival rate for this prothesis.
Knee warmth is a common clinical observation following total knee arthroplasty (TKA). This can cause concern that infection is present. The purpose of our study was to establish the pattern of knee skin temperature following uncomplicated TKA. It was a prospective study carried out between 2001 and 2004. A pocket digital surface thermometer was used. A preliminary study established that the best site to measure knee skin temperature was superomedial to the patella and the best time was 12 noon. Patients with an increased risk of infection and those with a contralateral knee pathology or a previous surgery were excluded. Forty-eight patients fulfilled the inclusion criteria and consented to participate; the skin temperature of operated and contralateral knees was measured pre-operatively and daily during the first six weeks post-operatively. Measurements were also taken at 3, 6, 12 and 24 months following surgery. During the course of the study, patients developing complications of the operated knee or any pathology of the contralateral knee were excluded. Thirty-two patients completed the main study. Following surgery, systemic and both knees temperatures increased. Whereas systemic and contralateral knee temperatures settled within one week, the operated knee temperature took a longer time. The difference in temperature between the two knees had a mean value of +2.9°C at 7 days. This mean value decreased to +1.6°C at 6 weeks, +1.3°C at 3 months, +0.9°C at 6 months +0.3°C at 12 months and +0.04°C at 24 months. Following uncomplicated TKA, the operated knee skin temperature increases compared to the contralateral knee. This increase peaks at day 3 and diminishes slowly over several months; however, it remains statistically significant up to 6 months. These results correlate with the findings of previous studies that showed a prolonged elevation of inflammatory markers.
