Background and purpose — Using contemporary indications, up to 50% of patients undergoing knee arthroplasty are eligible for unicompartmental knee arthroplasty (UKA), and lower UKA use likely reflects a restrictive approach to patient selection. Since broader indications have been successfully introduced, and low surgical volume and UKA percentage (usage) are associated with higher revision rates, it is of interest whether the actual use of UKA has changed accordingly. We explored this by assessing time trends in patient demographics and whether these are associated with center UKA volume and usage. Patients and methods — From the Danish Knee Arthroplasty Registry, we included 8,501 medial UKAs performed for primary osteoarthritis during 2002–2016. Using locally weighted regression, we examined changes—both overall and by center volume and usage (low vs high)—in sex distribution, age, weight, and preoperative American Knee Society Score (AKSS-O). Results — Over the last 20 years, UKA use in Denmark has been increasing steadily. Age, weight, and proportion of men all increased regardless of volume and usage. AKSS-O showed an initial increase followed by a decrease. In low-usage and low-volume centers, the proportion of women was higher, patients were younger, weighed less, and had higher AKSS-O scores; however, for age and AKSS-O, the groups were converging during the last part of the period. Interpretation — Characteristics of UKA patients have changed in the last 15 years irrespective of center volume and usage. We found between-group differences for both volume and usage, though with convergence for age and AKSS-O, which suggests an increasingly uniform approach to patient selection.

BackgroundUpper limb paresis is one of the most frequent and persistent impairments following stroke. Only 12–34% of stroke patients achieve full recovery of upper limb functioning, which seems to be required to habitually use the affected arm in daily tasks. Although the recovery of upper limb functioning is most pronounced during the first 4 weeks post stroke, there are few studies investigating the effect of rehabilitation during this critical time window. The purpose of this trial is to determine the effect of electrical somatosensory stimulation (ESS) initiated in the acute stroke phase on the recovery of upper limb functioning in a nonselected sample of stroke patients.Methods/designA sample of 102 patients with upper limb paresis of varying degrees of severity is assigned to either the intervention or the control group using stratified random sampling. The intervention group receives ESS plus usual rehabilitation and the control group receives sham ESS plus usual rehabilitation. The intervention is applied as 1 h of ESS/sham ESS daily, followed by motor training of the affected upper limb. The ESS/sham ESS treatment is initiated within 7 days from stroke onset and it is delivered during hospitalization, but no longer than 4 weeks post stroke. The primary outcome is hand dexterity assessed by the Box and Block Test; secondary outcomes are the Fugl-Meyer Assessment, hand grip strength, pinch strength, perceptual threshold of touch, degree of pain, and modified Rankin Scale score. Outcome measurements are conducted at baseline, post intervention and at 6-month follow-up.DiscussionBecause of the wide inclusion criteria, we believe that the results can be generalized to the larger population of patients with a first-ever stroke who present with an upper limb paresis of varying severity. On the other hand, the sample size (n = 102) may preclude subgroup analyses in such a heterogeneous sample. The sham ESS treatment totals a mere 2% of the active ESS treatment delivered to the intervention group per ESS session, and we consider that this dose is too small to induce a treatment effect.Trial registrationClinicalTrials.gov, NCT02250365. Registered on 18 September 2014.Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-017-1815-9) contains supplementary material, which is available to authorized users.

ObjectivesOsteoarthritis is a common and severe, multifactorial disease with a well-established genetic component. However, little is known about how genetics affect disease progression, and thereby the need for joint placement. Therefore, we aimed to investigate whether the genetic associations of knee and hip osteoarthritis differ between patients treated with joint replacement and patients without joint replacement.MethodsWe included knee and hip osteoarthritis cases along with healthy controls, altogether counting >700 000 individuals. The cases were divided into two groups based on joint replacement status (surgical vs non-surgical) and included in four genome-wide association meta-analyses: surgical knee osteoarthritis (N = 22 525), non-surgical knee osteoarthritis (N = 38 626), surgical hip osteoarthritis (N = 20 221) and non-surgical hip osteoarthritis (N = 17 847). In addition, we tested for genetic correlation between the osteoarthritis groups and the pain phenotypes intervertebral disc disorder, dorsalgia, fibromyalgia, migraine and joint pain.ResultsWe identified 52 sequence variants associated with knee osteoarthritis (surgical: 17, non-surgical: 3) or hip osteoarthritis (surgical: 34, non-surgical: 1). For the surgical phenotypes, we identified 10 novel variants, including genes involved in autophagy (rs2447606 inATG7) and mechanotransduction (rs202127176 inPIEZO1). One variant, rs13107325 inSLC39A8, associated more strongly with non-surgical knee osteoarthritis than surgical knee osteoarthritis. For all other variants, significance and effect sizes were higher for the surgical phenotypes. In contrast, genetic correlations with pain phenotypes tended to be stronger in the non-surgical groups.ConclusionsOur results indicate differences in genetic associations between knee and hip osteoarthritis depending on joint replacement status.

Aging negatively affects collagen-rich tissue, like tendons, but in vivo tendon mechanical properties and the influence of physical activity after the 8th decade of life remain to be determined. This study aimed to compare in vivo patellar tendon mechanical properties in moderately old (old) and very old adults and the effect of short-term resistance training. Twenty old (9 women, 11 men, >65 yr) and 30 very old (11 women, 19 men, >83 yr) adults were randomly allocated to heavy resistance training (HRT) or no training (CON) and underwent testing of in vivo patellar tendon (PT) mechanical properties and PT dimensions before and after a 3-mo intervention. Previous measurements of muscle properties, blood parameters, and physical activity level were included in the analysis. Data from 9 old HRT, 10 old CON, 14 very old CON, and 12 old HRT adults were analyzed. In addition to lower quadriceps muscle strength and cross-sectional area (CSA), we found lower PT stiffness and Young's modulus ( P < 0.001) and a trend toward the lower mid-portion PT-CSA ( P = 0.09) in very old compared with old subjects. Daily step count was also lower in very old subjects ( P < 0.001). Resistance training improved muscle strength and cross-sectional area equally in old and very old subjects ( P < 0.05) but did not affect PT mechanical properties or dimension. We conclude that PT material properties are reduced in very old age, and this may likely be explained by reduced physical activity. Three months of resistance training however, could not alter PT mechanical properties in very old individuals. NEW & NOTEWORTHY This research is the first to quantify in vivo tendon mechanical properties in a group of very old adults in their eighties. Patellar tendon stiffness was lower in very old (87 yr on average) compared with moderately old (68 yr on average) individuals. Reduced physical activity with aging may explain some of the loss in tendon stiffness, but regular heavy resistance training for 3 mo was not sufficient to change tendon mechanical properties.