BACKGROUND: Minocycline-induced pigmentation of bone (black bone) is well described in tooth-bearing intra-oral bone, but is less known in periarticular bone in patients who have undergone total joint arthroplasty. On a retrospective basis, we investigated the short-term clinico-radiological results of total joint arthroplasties in which the patient developed minocycline-induced periarticular black bone. METHODS: We found 5 cases (0.08%), in 4 patients, of periarticular bone pigmentation revealed during total joint arthroplasties (2 hips, 2 knees, and 1 ankle) in our series of total joint surgeries (6,548 cases) over a 10-year time period in our 3 institutes. Their mean age was 56 years at surgery. All patients had received long-term minocycline treatment. Mean dosage and duration of minocycline was 160 mg/day and 2.2 years, respectively. Minocycline had been prescribed for reactive arthritis (one), rheumatoid arthritis (two) and late infection after total joint arthroplasty (two patients). Mean follow-up period was 3.4 years after the surgeries. RESULTS: All cases had black or brown pigmentation in the periarticular bones during the surgery. There was no pigmentation in the cartilage or soft tissues of the joints. The mean Japanese Orthopaedic Association (JOA) score or Japanese Society for Surgery of the Foot (JSSF) scale for rheumatoid arthritis foot and ankle joints at latest follow-up (case 1, 66; case 2, 87; case 3, 77; case 4, 77; case 5, 80) improved compared to those of pre-surgery (case 1, 47; case 2, 45; case 3, 55; case 4, 34; case 5, 55). No implant loosening was noted on radiographic examination during the follow-up period. No abnormal bone formation, bone necrosis, hemosiderin deposition, malignancy or metallic debris was found on histological examination. CONCLUSIONS: No clinico-radiological symptoms of total joint arthroplasties showed in the patients with minocycline-induced periariticular black bone in the short-term. Systemic minocycline treatment has the potential to induce significant black pigmentation of many tissues. In particular, minocycline-induced pigmentation of periarticular bone may be accelerated by inflammation due to rheumatic or pyogenic arthritis. Surgeons should recognize the risk of bone pigmentation in inflamed joints due to the systemic treatment of minocycline and explore its influence on periarticular bone and total joint arthroplasty in the long-term.
Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents/*adverse effects/therapeutic use ; Antibiotic Prophylaxis/adverse effects ; Arthritis/drug therapy/*pathology/prevention & control ; Arthroplasty, Replacement/*methods ; Bone and Bones/*drug effects/pathology ; Female ; Humans ; Male ; Middle Aged ; Minocycline/*adverse effects/therapeutic use ; Retrospective Studies ; Skin/pathology ; Skin Pigmentation

Objective：The movement of an elderly person involving stepping over a bathtub makes them prone to falls and requires caution. Gait analysis suggested that the risk of falling increases with time spent in supporting both legs. A similar relationship was expected for side-straddling motion. This study aims to analyze differences in the side-straddling movements between THA patients who did not fully recover their functional balance, mobility, or walking ability from the viewpoint of the ratio of time spent supporting both legs.Methods：Eleven patients with hip osteoarthritis underwent initial unilateral THA via a posterior approach. Using a portable three-dimensional motion analyzer, we calculated the percentages of time spent supporting both legs while entering the bathtub, and exiting the bathtub with a handrail and examined the factors associated with percent of the time spent supporting both legs.Results：The percentage of time spent supporting both legs when exiting the bathtub was significantly lesser when exiting using the nonoperative than the operated side. A negative correlation was found between the percentages of time spent supporting both legs. while exiting the bathtub, and the percentage of handrail load values.Conclusion：The risk of falling may be reduced by using the nonoperative leg as the leading leg when exiting a bathtub. Use of handrails contributes to a reduction in fall risk.

Introduction : We examined the characteristics of paralytic scoliosis using plain radiography.Subjects and methods : We recruited fourteen patients aged ≥ 15 years old with no history of bone surgery at the time of their final observation. Participants included those who had cerebral palsy or those who had a history of encephalitis and underwent spinal frontal plain radiography in the supine position at different time points. We evaluated gross motor function, position and direction of the curve, Cobb angle, rate of variability, and degree of progression at 5-year intervals. We measured the percentage of migration using hip frontal plain radiography to assess hip dislocation.Results : The final Cobb angles were 82.0°, 118.4°, and 92.3°for the thoracic, thoracolumbar (TL), and lumbar curvatures, respectively. TL curvatures showed the greatest progression, although this was not statistically significant. The progression was greatest in the 10-15-year age group (12.5°annually). The final Cobb angles in the hip dislocation, subluxation, and no dislocation groups were 102.8°, 108.8°, and 87.5°, respectively；the difference was not statistically significant. No relationship was observed between the location or progression of curvature and the state of the hip location.Discussion : Paralytic scoliosis progressed most rapidly in 10-15-year-old patients, especially in those with TL lesions. We did not detect any relationships between hip dislocation and Cobb angle, but these parameters progressed at different rates in different patients.