Knee manipulation after total knee arthroplasty: comparison of two implant designs.

Substantial postoperative stiffness requiring manipulation is a well-recognized complication of total knee replacement. This study sought to determine whether the Medial-Pivot (MP) knee (Wright Medical, Memphis, TN) or the Double-High (DH) knee (Wright Medical) is more often associated with manipulation under anesthesia (MUA) for post-total knee arthroplasty (TKA) knee stiffness. It was hypothesized that manipulation rates would be similar. Retrospective review of 755 TKA patients showed that 4.1% required MUA, which is comparable to the literature. Manipulation by MUA for DH and MP knees was generally successful, with an average overall improvement in knee flexion of nearly 30°. MP and DH knees appear to have a lower than average prevalence of post-TKA knee stiffness requiring manipulation when compared with the literature. The number of MP and DH knees requiring MUA did not appear to differ substantially.

The EIUS unicompartmental knee design: early failure in elderly patients.

This report presents the results of 34 unicompartmental knee replacements in 28 elderly patients. The mean age of patients at the time of index surgery was 78.7 years. All cases were performed by a single surgeon over a 16-month period. In all cases, the EIUS Unicompartmental Knee System (Stryker, Mahwah, NJ) was used. The surgeon was technically experienced at implanting EIUS knee prostheses prior to the start of this study.Knees were evaluated by Knee Society Score through 5 years, and patients were followed up by phone interviews for a minimum period of 8 years. With revision as the end point, the 5-year failure rate was 14.7% (n = 5), and the mean time to failure was 25.6 months (range: 4 to 44 months).At 8 years follow-up, 3 patients (4 knees) died for reasons unrelated to the knee implant, and 2 patients (4 knees) were lost to follow-up. Three knees in 3 patients were revised at 5.75 years, 7.0 years, and 8.0 years, respectively. The majority of knees that did not experience early failure remained pain and symptom free at minimum 8 years follow-up.We suspect the early failures were more likely due to a combination of the design characteristics and instrumentation of the EIUS prosthesis than surgical technique.

Glucose sensing in transdermal body fluid collected under continuous vacuum pressure via micropores in the stratum corneum.

Application of continuous vacuum pressure on skin perforated with tiny micropores created by a focused beam from a low-cost laser system can result in access to a clear, transdermal body fluid (TDF) for the continuous measurement of glucose in vivo. Two clinical studies were performed to assess the feasibility of this approach. In the first study, 56 diabetic subjects were porated on either the arm or abdomen, and glucose was measured in their TDF using a custom assay system contained in a patch that was affixed to the skin above the poration site. The continuous readings of glucose in TDF were compared with fingerstick blood measured every half-hour over a 2-day period, resulting in 1,167 paired data points that yielded a correlation of 0.8745 with 97.75% of the readings in the Clarke Error Grid A and B zones. In a second study, 187 diabetic and 65 nondiabetic subjects had glucose measurements from their TDF made using a commercially available glucose strip and meter. A total of 4,059 data pairs (discrete TDF and capillary blood) were collected over a 2-day period, resulting in a correlation of 0.946 with 99% of the readings in the Clarke Error Grid A and B zones. These studies indicate that TDF drawn through micropores in the stratum corneum of the skin potentially can provide a lesser invasive and continuous method of measuring glucose in diabetic individuals.