Reliability and validity of the Japanese version of the short questionnaire to assess health-enhancing physical activity (SQUASH) scale in older adults.

[Purpose] We tested the reliability and validity of the Japanese version of the Short Questionnaire to Assess Health-enhancing Physical Activity scale in asymptomatic older adults and sought to confirm discriminator validity in women with osteoarthritis. [Subjects] The participants included an asymptomatic comparison group (men and women) and women with knee or hip osteoarthritis. [Methods] The test-retest method was used to assess reliability. The International Physical Activity Questionnaire was chosen to assess criterion-related validity. Discriminator validity was assessed by comparing the asymptomatic and osteoarthritis groups. [Results] Mean age for the asymptomatic groups was 63 ± 6 years for men (n = 23) and 61 ± 7 years for women (n = 51), and it was 63 ± 9 years for the osteoarthritis group (n = 32). The total score and scores for all items, except for heavy housework items, were significantly correlated with the retest. Criterion-related validity showed significantly weak to moderate correlations between the respective scale categories. For discriminator validity, the total scores and scores for bicycle commuting, light housework, and three leisure items differed significantly between the asymptomatic and osteoarthritis groups. [Conclusion] The Short Questionnaire to Assess Health-enhancing Physical Activity scale is a reliable and valid measure in asymptomatic older adults, and can discriminate between osteoarthritic and asymptomatic women.

Radiolucent zone of the patella following total knee arthroplasty without patellar resurfacing.

BACKGROUND: The radiolucent zones in the patella are sometimes observed in patients who have undergone total knee arthroplasty (TKA) without patellar resurfacing. On the basis of radiological findings from our clinical experience, we hypothesize that the pathogenesis of this lesion may be similar to that of the lesions of spontaneous osteonecrosis, and this lesion may be due to both osteoporosis and stress concentration. The present study aimed to determine the incidence of the radiolucent zone after TKA without patellar resurfacing. Moreover, the roles of osteoporosis and patellar morphology, which are related to the stress distribution in the patella, were also investigated. METHODS: We studied 48 knees of 38 patients who underwent primary TKA using the Genesis II prosthesis. Axial radiographs taken 1 year postoperatively were used to assess the incidence of the radiolucent zone. The World Health Organization fracture risk assessment tool (FRAX) score and the preoperative patellar facet angle were compared between patients with and without the radiolucent zones. RESULTS: Five patellae (10.4%) showed the radiolucent zones postoperatively (the radiolucent group), whereas no such lesions were found in the remaining 43 patellae (the normal group). The major osteoporotic fracture risk of the radiolucent group calculated using the FRAX was 24.8% and significantly higher than that in the normal group (14.7%; p = 0.01). The average patellar facet angle in the radiolucent group was 123.6°, which was significantly smaller than that in the normal group (133.6°; p = 0.003). DISCUSSION AND CONCLUSIONS: The results of the present study suggest that both underlying osteoporosis and a steep patellar facet angle may play an important role in the pathogenesis of the radiolucent zones in patellae after TKA without patellar resurfacing. Patellar resurfacing may be considered, particularly in osteoporotic patients who have a steep patellar facet angle, to avoid the appearance of the postoperative radiolucent zone in the patella.

Osteochondritis dissecans of the knee in identical twins: a report of two cases.

We report the second case of osteochondritis dissecans (OCD) of the knee in identical twins (bilaterally in one and unilaterally in the other). Fixations with bio-absorbable pins, cylindrical osteochondral graft, and osteochondral mosaicplasty were all successful and bone union was achieved. We considered that genetic factors remain essential even if other factors (particularly repetitive trauma) are mainly responsible for the occurrence of OCD.

Patellar morphology and femoral component geometry influence patellofemoral contact stress in total knee arthroplasty without patellar resurfacing.

PURPOSE: The objective of this study was to determine the effect of patellar morphology and implant design on patellofemoral contact stress in total knee arthroplasty (TKA) without patellar resurfacing. METHODS: Radiographic investigation: One hundred and fifty-seven knees of 127 patients were included in the study. Implants used in the present series were Low Contact Stress (LCS), Genesis II and NexGen. The relationship between the pre-operative patellar facet angle and newly identified post-operative osteosclerosis was assessed. Finite element analysis: Using patient-specific patellar three-dimensional finite element models, the relationship between the patellar facet angle and mean von Mises stress within the patella was calculated at flexion angles of 15°, 45°, 75° and 105°. RESULTS: Radiographic investigation: Post-operative osteosclerosis was observed with decreasing patellar facet angle in the Genesis II (odds ratio = 0.72; 95% confidence interval, 0.55-0.93; P = 0.012) and NexGen implants (odds ratio = 0.87; 95% confidence interval, 0.77-0.99; P = 0.029). Patients treated with the Genesis II had significantly more advanced osteosclerosis than those treated with the other two implants. Finite element analysis: A negative correlation was found between the patellar facet angle and the mean von Mises stress for all three implants. The Genesis II showed significantly higher von Mises stress than the other two implants at flexion angles of 15°, 45° and 105°. CONCLUSIONS: Both patellar morphology and femoral component geometry influence patellofemoral contact stress in total knee arthroplasty without patellar resurfacing. LEVEL OF EVIDENCE: Case control study, Level III.

Bony island within the articular cartilage of the knee in a child: a rare condition for early osteoarthritis.

Articular cartilage is a specific type of connective tissue composed of hydrated proteoglycans within a matrix of collagen fibrils. In the elderly population, it shows degenerative changes that may results in osteoarthritis. The more severe form of osteoarthritis occasionally demonstrates bone formation within the cartilage, which is designated as a bony protuberance, however, such lesions are rare in children. This report presents the case of a 10-year-old boy with a bony protuberance within the articular cartilage of the knee. The patient initially complained of knee pain and he subsequently developed flexion contracture. Radiological and arthroscopic examinations revealed a bony protuberance in the articular cartilage and degenerative changes of the cartilage above it. He was successfully treated by the removal of the bony protuberance and osteochondral grafting. The bony protuberance may have caused cartilage degradation since the thickness of the cartilage above it was thinner than that around the lesion. The bony protuberance within the articular cartilage formed in the younger population may be a possible cause of osteoarthritis. This case is a noteworthy with regard to the pathogenesis of osteoarthritis.

Bony island within the articular cartilage of the knee in a child: a rare condition for early osteoarthritis.

Articular cartilage is a specific type of connective tissue composed of hydrated proteoglycans within a matrix of collagen fibrils. In the elderly population, it shows degenerative changes that may results in osteoarthritis. The more severe form of osteoarthritis occasionally demonstrates bone formation within the cartilage, which is designated as a bony protuberance, however, such lesions are rare in children. This report presents the case of a 10-year-old boy with a bony protuberance within the articular cartilage of the knee. The patient initially complained of knee pain and he subsequently developed flexion contracture. Radiological and arthroscopic examinations revealed a bony protuberance in the articular cartilage and degenerative changes of the cartilage above it. He was successfully treated by the removal of the bony protuberance and osteochondral grafting. The bony protuberance may have caused cartilage degradation since the thickness of the cartilage above it was thinner than that around the lesion. The bony protuberance within the articular cartilage formed in the younger population may be a possible cause of osteoarthritis. This case is a noteworthy with regard to the pathogenesis of osteoarthritis.

Function of the shoulder muscles during arm elevation: an assessment using positron emission tomography.

Although 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) positron emission tomography (PET) has been used for the assessment of skeletal muscle activities, its application to the shoulder muscles is only sparse. The purpose of this study was to investigate the activities of the shoulder muscles during arm elevation using PET. Six healthy volunteers performed an arm elevation exercise before and after FDG injection. The exercise consisted of 200 repetitions of arm elevation in the scapular plane with a 0.25-kg weight fixed to the wrist on both arms. PET examination was performed 50 min after FDG injection. For control data, PET scan was repeated for each subject on a separate day without any exercise. The volume of interest was established for each shoulder muscle. The subscapularis was divided into three portions (superior, middle, and inferior). The standardized uptake value (SUV) was calculated in each muscle to quantify its activity. The SUVs increased significantly after exercise in the deltoid, supraspinatus, and the superior portion of subscapularis. Among three divided portions of the subscapularis, the SUV of the superior one-third was significantly greater than the rest of the muscle after exercise. Our current study clearly indicated that there were two functionally different portions in the subscapularis muscle and the superior one-third played an important role during arm elevation in the scapular plane.

Histologic findings and possible causes of osteochondritis dissecans of the knee.

BACKGROUND: The histologic findings of osteochondritis dissecans of the knee vary widely, leading to differences in the interpretation of its origins. Hypothesis The differences in the histologic findings of osteochondritis dissecans might represent a course of pathologic progression. STUDY DESIGN: Descriptive laboratory study. METHODS: Twelve knees in 11 patients (average age, 16 years) with osteochondritis dissecans of the medial femoral condyle were treated by biological internal fixation. During the surgery, cylinder osteochondral plugs were taken from the center of the osteochondritis dissecans lesion and examined with light microscopy. RESULTS: A complete or partial cleft separated the specimens into 2 parts: basal and fragment sides. The surface of the basal side was covered with dense fibrous or cartilaginous tissue and active bone remodeling was found beneath the surface. In the fragment side, the deep surface was also covered with dense fibrous or cartilaginous tissue and the articular surface consisted of normal articular cartilage. The area between these 2 surfaces could be classified into 3 types: (1) necrotic subchondral trabeculae, (2) viable subchondral trabeculae, and (3) cartilage without bone trabeculae. CONCLUSION: Based on the histologic findings of this study, the following origins and the pathologic progression of osteochondritis dissecans might be assumed: the initial change in the subchondral area is bone necrosis or subchondral fracture; the necrotic bone is then absorbed and replaced either by viable subchondral trabeculae or cartilage without bone trabeculae. CLINICAL RELEVANCE: The results of this histologic study provide readers with several insights about the causes and treatment options of osteochondritis dissecans.

Muscle activity during a dash shown by 18F-fluorodeoxyglucose positron emission tomography.

BACKGROUND: 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been used to examine muscle activity during running. The dash is a basic activity in various kinds of sports but differs from running in terms of intensity and severity. The purpose of this study was to evaluate muscle activity during running at full speed using FDG PET. METHODS: Six healthy men were investigated during a dash for 10 min after intravenous injection of FDG (37 MBq). Another six healthy men were studied as controls. PET images were obtained 45 min after the FDG injection. Regions of interest were drawn on the anterior and posterior thighs and the anterior and posterior legs. The standardized uptake value (SUV) was calculated to examine the FDG uptake of muscle tissue per unit volume according to an equation. RESULTS: In the control group, the mean SUVs of the anterior thigh, posterior thigh, anterior leg, and posterior leg were 0.49 +/- 0.04, 0.44 +/- 0.02, 0.46 +/- 0.05, and 0.44 +/- 0.07, respectively. In the dash group, the mean SUVs of the anterior thigh, posterior thigh, anterior leg, and posterior leg were 0.74 +/- 0.20, 0.79 +/- 0.08, 0.61 +/- 0.07, and 0.60 +/- 0.08, respectively. FDG accumulation of every one of the four compartments in the dash group was significantly higher than that in the control. FDG accumulation of the posterior thigh was significantly higher than that of the anterior and the posterior leg in the dash group (P < 0.02). CONCLUSION: Based on the results of our investigation, posterior thigh muscles were especially active during a dash.

Traumatic separation of a type I bipartite patella: a report of four knees.

Four knees in three patients with traumatic separation of a Type I bipartite patella are reported. Sudden anterior knee pain and an audible pop occurred at the time of the injury and the patients had aching or dull pain before the traumatic episode. Previous aching or dull pain led us to differentiate this type of injury from a usual transverse fracture. A round fracture line seen on the radiographs also led us to differentiate this type of injury from a stress fracture. Accordingly, the diagnosis of a traumatic separation of a Type I bipartite patella was confirmed. This is the first report of a traumatic separation of a Type I bipartite patella to our knowledge.

Pigmented villonodular synovitis of the knee with lesions of the bursae.

Five patients with pigmented villonodular synovitis of the knee associated with lesions of the posterior periarticular bursae were treated by posterior exploration, excision of the bursal tissue, and routine anterior synovectomy of the knee. It was hypothesized that complete excision of the posterior periarticular bursae would reduce the high recurrence rate of pigmented villonodular synovitis of the knee. To completely excise the periarticular lesions, two posterior oblique skin incisions were used. In all patients, periarticular lesions were seen clearly on computed tomography scans after air arthrography and on magnetic resonance imaging scans. The patients were followed up for 6.9 years on average (range, 3.3-8.1 years) after surgery. One of five patients required reoperation because of recurrence. Two of five patients required manual mobilization after release of the intraarticular adhesion. However, in the remaining three patients, who started continuous passive motion exercise immediately after surgery, full range of motion was restored within 3 months after the operation. Complete excision of the periarticular lesions is recommended to reduce the high recurrence rate, and continuous passive motion exercise immediately after surgery also is recommended to prevent reduction of range of motion.