Bilateral Neuropathy Dermatitis Following Simultaneous Bilateral Total Knee Arthroplasty: A Case Report.

CASE: A 65-year-old man developed bilateral knee dermatitis in the distribution of the infrapatellar nerve 3 months following uncomplicated simultaneous bilateral total knee arthroplasty (TKA) for osteoarthritis. The patient was treated with topical corticosteroids, and the rash had resolved after 6 months. At the 2-year follow-up, there had been no recurrences. CONCLUSION: Neuropathy dermatitis is a rare cutaneous complication of TKA. Although a few theories exist, there is no definitive explanation for the underlying pathophysiology of this disease process.

A low-cost digital templating system for total hip arthroplasty.

Acetate templating for total hip arthroplasty (THA) is cumbersome and inaccurate. High cost hampers mainstream use of digital templating despite ease of use and accuracy. The aim of this study was to validate a low-cost digital THA templating system. Low-cost digital templating software was created using C# programming language. On the basis of power calculations, three surgeons templated 20 consecutive anteroposterior pelvis X-rays using this software against an industry standard. Intraclass correlation coefficient for both systems was approximately .90 for component size and femoral neck cut position. Bland-Altman plots demonstrated that both systems predicted actual implant size with similar accuracy. Interrater reliability was not significantly different between the two systems. This low-cost digital THA templating system is up to 12-fold lower in cost than currently available software with similar accuracy.

All-polyethylene tibial components in octogenarians: survivorship, performance, and cost.

The ideal recipient for an all-polyethylene tibial (APT) component continues to be controversial. Several recent randomized clinical studies have demonstrated clinical efficacy of APT when compared to metal backed tibial (MBT) components in relation to survival and clinical outcomes measures, particularly in an elderly population. In this retrospective series, 166 knees in 130 patients (age > 80 years) received an APT component. Average follow-up for the living and deceased was 5.7 and 5.2 years, respectively. There were no APT failures at the time of most recent follow-up. Knee Society function score improved from 30 to 48. Almost all respondents reported either good or excellent satisfaction with their outcome. The average cost savings of using APT instead of MBT component can be substantial. We believe octogenarian patients represent the ideal population for an APT component, that functional outcomes and satisfaction levels will be acceptable to those patients, and that the component will outlast the remaining life of the patient while also potentially providing a substantial cost savings, compared with the cost of MBT components.

Charcot neuroarthropathy of the foot and ankle.

Charcot neuroarthropathy is a common cause of morbidity in persons with diabetes mellitus and sensory neuropathy. Although Charcot neuroarthropathy is rare, it likely will become more prevalent in conjunction with increased incidence of diabetes mellitus. Prevention of disease progression remains the mainstay of treatment, with surgical intervention usually reserved for refractory cases. Late deformities are often complicated by chronic ulceration, infection, and osteomyelitis. The clinical presentation is best summarized with the Eichenholtz classification, and progression often follows a predictable pattern. Although Charcot neuroarthropathy is a clinical diagnosis, recent advances in diagnostic imaging have eased the clinical challenge of deciphering infection from Charcot changes. Advances in surgical treatment have demonstrated new options for limb salvage. Pharmacologic therapies directed toward decreasing bone resorption have also shown promise for treatment, but clinical application remains theoretical.

The measurement of the variation in the surface strains of Achilles tendon grafts using imaging techniques.

Uniaxial tensile tests are commonly used to characterize the structural and material properties of tendons and ligaments. During these tests, the stress and strain distributions applied to the specimen are assumed to be uniform. However, few studies have investigated the strain distributions throughout the tissue. The purpose of this study was to use imaging techniques to measure the strains around the circumference of 11 mm wide Achilles tendon grafts during a uniaxial tensile test. Pairs of radiopaque beads with a diameter of 2mm were affixed around the mid-substance of the tendon in four different locations. The motion of the beads was recorded using a cine fluoroscope. This system was shown to measure the displacement of the beads with an accuracy of 0.02 mm. During the uniaxial tensile test, large variations in local tissue strains were observed. At 10 MPa of applied stress, the local tissue strain varied from an average of 2.5-8.7%, an increase in strain of more than three times. As a result of these large variations, the modulus calculated from the stress-strain data varied from an average of 217 to 897 MPa, an increase of approximately 4 times. Furthermore, these data suggest that underestimates of the elastic modulus may result if a uniform strain distribution is assumed. These results indicate that during uniaxial tensile tests, the assumption of uniform stress and strain distributions should be carefully considered and small, uniform specimens should be used when measuring the material properties of soft tissues.

The effect of length on the structural properties of an Achilles tendon graft as used in posterior cruciate ligament reconstruction.

BACKGROUND: The clinical outcomes of posterior cruciate ligament reconstruction are varied. No previous studies have investigated the effect of graft length on the structural properties of the graft. HYPOTHESIS: Graft length significantly affects the structural properties of posterior cruciate ligament grafts. STUDY DESIGN: Controlled laboratory study. METHODS: Eight Achilles tendon grafts were tested under tensile loads up to 400 N at 3 different lengths: long (75 mm), medium (48 mm), and short (34 mm). These 3 lengths represent midtunnel fixation, inlay fixation, and fixation near the ligament insertions. RESULTS: Shortening the graft from both long to medium and from medium to short increased the stiffness by approximately 25%. Long and medium grafts displaced significantly more than medium and short grafts, respectively. CONCLUSION: The effective length of a graft, which is determined by where it is fixed, should be considered an important variable in posterior cruciate ligament reconstruction.