Approved by the Food and Drug Administration in 2004, the Phase
III Oxford Medial Partial Knee is used to treat anteromedial osteoarthritis
(AMOA) in patients with an intact anterior cruciate ligament. This
unicompartmental knee arthroplasty (UKA) is relatively new in the
United States, and therefore long-term American results are lacking. This is a single surgeon, retrospective study based on prospectively
collected data, analysing a consecutive series of primary UKAs using
the Phase III mobile-bearing Oxford Knee and Phase III instrumentation. Between July 2004 and December 2006, the senior author (RHE)
carried out a medial UKA in 173 patients (213 knees) for anteromedial
osteoarthritis or avascular necrosis (AVN). A total of 95 patients were men and 78 were women. Their mean
age at surgery was 67 years (38 to 89) and mean body mass index
29.87 kg/m2 (17 to 62). The mean follow-up was ten years (4 to 11).Aims
Patients and Methods
Introduction. Septic arthritis of the native knee often results in irreversible joint damage leading to the need for a total knee arthroplasty (TKA). This study examines the mid-term risk of periprosthetic joint infection (PJI), aseptic revision, any revision, and any reoperation in primary TKAs after septic arthritis of the native knee compared to a control cohort of primary TKAs performed for osteoarthritis (OA). Methods. We retrospectively identified 215 primary TKAs performed between 1971 and 2016 at a single institution following septic arthritis of the native knee. Eighty-two percent (177 cases) were treated in a single setting, whereas a two-stage exchange arthroplasty protocol was utilized in 18% (39 cases) for ongoing or suspected active native knee septic arthritis. Each case was matched 1:1 based on age, sex, body mass index (BMI), and surgical year to a primary TKA for OA. Mean age and BMI were 63 years and 30 kg/m2, respectively. Mean follow-up was 9 years. Results. Survivorship free from any infection (inclusive of PJI and wound infections) at 10 years was 87% in the septic arthritis cohort and 98% for the OA cohort (HR=6.5, p<0.01). Survivorship free of PJI at 10 years was 90% in the septic arthritis and 99% in the OA group (HR=6; p<0.01). There was no difference in the rate of infection when TKA occurred within 5 years of a septic arthritis diagnosis compared to a diagnosis that occurred >5 years from the TKA. The survivorship free of aseptic revision at 10 years was 83% for the septic arthritis cohort and 93% for the OA cohort (HR=2.5, p<0.01). When combining the above survivorships free of aseptic and septic revisions, the survivorship free of any revision at 10 years was 78% in the septic arthritis cohort and 91% in the OA cohort (HR=3, p<0.01). The
Introduction. Both mobile bearing and fixed bearing unicompartmental knee arthroplasty (UKA) have demonstrated clinical success. However, much debate persists about the superiority of a single design. Currently most clinical data is based on high volume centers data, however to reduce bias, we undertook a through review of retrospective national joint registries. In this study, we aim to investigate UKA implant utilization and survivorship between 2000 and 2018. Methods. Ten annual joint registry reports of various nations were reviewed. Due to the variable statistical methods of reporting implant use and survivorship we focused on three registries: Australia (AOANJRR), New Zealand (NZJR), United Kingdom (NJR) for uniformity. We evaluated UKA usage, survivorship, utilization and revision rates for each implant. Implant survivorship was reported in the registries and was compared within nations due to variation in statistical reporting. Results. UKAs accounted for 7.24–10.3% of all primary knee surgeries. The most popular implants were, in order of popularity, the Oxford (ZimmerBiomet, Warsaw IN), ZUK (Smith & Nephew, Memphis TN / LimaCorporate, Udine, Italy), Sigma HP (DePuy, Warsaw IN), Miller-Galante (ZimmerBiomet Warsaw IN), and Preservation (DePuy, Warsaw IN) models. UKA revision rates varied by nation and ranged from 8.22%–12.8%. The Sigma HP and ZUK designs had the lowest total percent revised in the registries-Australian (3.6% and 5.1%, respectively) and New Zealand (2.5% and 1.96%, respectively)-and demonstrated among the highest
Purpose. The success of total knee replacement (TKR) surgery can be attributed to improvements in TKR design, instrumentation, and surgical technique. Over a decade ago oxidized zirconium (OxZr) femoral components were introduced as an alternative bearing surface to cobalt-chromium (CoCr), based on strong in-vitro evidence, to improve the longevity of TKR implants. Early reports have demonstrated the clinical success of this material however no long-term comparative studies have demonstrated the superiority of OxZr implants compared to a more traditional CoCr implant. This study aims to compare long-term survivorship and outcomes in OxZr and CoCr femoral components in a single total knee design. Methods. We reviewed our institutional database to identify all patients whom underwent a TKA with a posterior stabilized OxZr femoral component with a minimum of 10 years of follow-up. These were then matched to patients whom underwent a TKA with the identical design posterior stabilized CoCr femoral component during the same time period by gender, age and BMI. All patients had their patella resurfaced. All patients were prospectively evaluated preoperatively and postoperatively at 6 weeks, 3 months, 12 months, 2 years and every 1 to 2 years thereafter. Prospectively collected clinical outcome measures included, Western Ontario and McMaster Universities osteoarthritis index (WOMAC), Short-Form 12 (SF-12) and Knee Society clinical rating scores (KSCRS). Charts and radiographs were reviewed to determine the revision rates and survivorship (both all cause and aseptic) at 10 years allowing comparison between the two cohorts. Paired analysis was performed to determine if differences existed in patient reported outcomes. Results. There were 194 OxZr TKAs identified and matched to 194 CoCr TKAs. There was no difference in average age (OxZr, 54.2 years; CoCr, 54.4 years), Gender (OxZr, 61.9% female; CoCr, 61.9% female) and average body mass index (OxZr, 35.9 kg/m2; CoCr, 36.4 kg/m2) between the two cohorts. There were no significant differences preoperatively in any of the outcome scores between the two groups (WOMAC (p=0.361), SF-12 (p=0.771) and KSCRS (p=0.161)). Both the SF12 (p=0.787) and WOMAC (p=0.454) were similar between the two groups, however the OxZr TKA cohort had superior KSCRS compared to the CoCr TKA cohort at a minimum of 10 years (173.5 vs. 159.1, p=0.002). With revision for any reason as the end point, there was no significant difference in
We set out to demonstrate the
Introduction. Obesity has been considered a relative contra-indication in unicompartmental knee arthroplasty (UKA) due to fear of high wear rates, loosening and tibial collapse. The aim of this study was to investigate the impact of high body mass index (BMI) on ten-year survivorship and five-year functional outcome after Oxford UKA, a fully congruous mobile bearing design with large contact area and low wear rate. Methods. This prospective study examines a consecutive series of 595 knees (mean age 66 years, range: 33-88) undergoing Oxford UKA with a minimum 5-year follow-up. Patients were divided into three groups; Group I (Normal body weight), BMI <25 (n=171), Group II (overweight), BMI 25- 30 (n=264), and Group III (Obese), BMI ≥30 (n=160). The survivorship and functional outcome (as assessed by change in Oxford Knee Score [DeltaOKS]) and Knee Society Score (KSS) for all three groups were compared. Results. The mean follow-up was 6.3 years. There was no significant difference in the