Recurrence of deformity after silicone implant and resection arthroplasty of the metatarsophalangeal joint for rheumatoid arthritis: long-term results.

OBJECTIVE: To examine the recurrence of deformity after silicone implant arthroplasty combined with resection arthroplasty for severe forefoot deformity in patients with rheumatoid arthritis. METHODS: We reviewed the long-term results of this procedure for 27 feet in 15 patients. Their average age and disease duration at the time of operation were 58.6 years and 17.5 years, respectively, and the average follow-up period was 10.3 years. RESULTS: An improved hallux valgus angle (45.3° preoperatively, 23.6° 6 months after operation) was maintained. By contrast, deformity and dislocation of lesser toe had recurred at the final follow-up; the angle between the proximal phalanx and the metatarsal of the second toe improved 13.4° with recurrence of 22.5°, the angle between the proximal phalanx and ground surface improved 22.4° with recurrence of 34.5. Furthermore, claw toe deformity at the final follow-up was significantly worse in the group whose hallux valgus deformity was observed 6 months after operation. CONCLUSION: This procedure could maintain the alignment of the first metatarsophalangeal joint, but the recurrence of claw toe deformity is a problem and the relation between the first toe and the lesser toe is an important consideration.

Prevention of pin tract infection with iodine-supported titanium pins.

BACKGROUND: Pin tract infection is one of the most common complications of external fixation. We developed techniques to coat titanium implant surfaces with iodine. This study clinically evaluated the infection-preventive effects and biological safety of iodine-coated external fixation pins. PATIENTS AND METHODS: Iodine-supported pins were placed in 39 limbs of 38 patients. The mean age of the patients was 33.6 years. Twenty-six patients were men and 12 were women. In all patients, the iodine-coated pins were used to prevent infection. There were 476 pin insertion sites. Pin sites were classified according to the Checketts-Otterburn classification (grade 1-6). White blood cells (WBC) and C-reactive protein (CRP) were measured pre- and postoperatively in all patients. To confirm whether iodine from the implant affected physiological functions, thyroid hormone levels in the blood were monitored. The change in the amount of iodine deposited in the body over time was calculated by examining the removed pins. RESULTS: External fixation was used for a mean duration of 6 months. Grade 1 infection was found in 2.5% of patients, and grade 2 infection in 1.1%. There was no patient with an infection of grade 3 or higher. Median WBC levels were in the normal range, and median CRP levels returned to <0.3 mg/dl within 3 weeks after surgery. Abnormalities of thyroid gland function were not detected. The amount of iodine was maintained for a long time, with approximately 40% remaining after 1 year. CONCLUSIONS: Iodine-supported titanium pins were able to decrease the pin tract infection rate and had no impact on thyroid function. These results suggest that iodine-coated titanium pins are biologically safe and effective at preventing pin tract infections.

Dislodgement and gastrointestinal tract penetration of bone cement used for spinal reconstruction after lumbosacral vertebral tumor excision: A case report.

INTRODUCTION: Polymethylmethacrylate (PMMA) cement is useful for spinal reconstruction, but can cause complications including new vertebral fractures, neurological disorders and pulmonary embolism. We report a case in PMMA cement used for spinal reconstruction after tumor curettage dislodged and penetrated the gastrointestinal tract. DIAGNOSES: The patient was diagnosed with a retroperitoneal extragonadal germ cell tumor at age 27 years. After chemotherapy and tumor resection, the tumor remained. It gradually increased in size and infiltrated lumbosacral vertebrae, causing him to present at age 35 years with increased low back pain. Image findings showed bone destruction in the vertebral bodies accompanied by neoplastic lesions. The left and right common iliac arteries and inferior vena cava were enclosed in the tumor on the anterior side of the vertebral bodies. Lumbosacral bone tumor due to direct extragonadal germ cell tumor infiltration was diagnosed. A 2-step operation was planned; first, fixation of the posterior side of the vertebral bodies, followed by tumor resection using an anterior transperitoneal approach, and spinal reconstruction using PMMA cement. After surgery, the PMMA cement gradually dislodged towards the anterior side and, 2 years 9 months after surgery, it had penetrated the retroperitoneum. The patient subsequently developed nausea and abdominal pain and was readmitted to hospital. The diagnosis was intestinal blockage with dislodged PMMA cement, and an operation was performed to remove the cement present in the small intestine. There was strong intra-abdominal adhesion, the peritoneum between the vertebral bodies and intestine could not be identified, and no additional treatment for vertebral body defects could be performed. After surgery, gastrointestinal symptoms resolved. CONCLUSION: Although this was a rare case, when using bone cement for vertebral body reconstruction, the way of anchoring for the cement must be thoroughly planned to assure no cement dislodgement can occur.

Stimulation of Rotator Cuff Repair by Sustained Release of Bone Morphogenetic Protein-7 Using a Gelatin Hydrogel Sheet.

Bone morphogenetic protein-7 (BMP-7) promotes not only osteogenesis but also matrix production in chondrocytes and tenocytes. However, because of its short half-life, maintaining local concentrations of BMP-7 is difficult. We examined the use of a gelatin hydrogel sheet (GHS) for the sustained release of BMP-7 in stimulating rotator cuff repair at the tendon-to-bone insertion. Twelve-week-old male Sprague-Dawley rats were used. Radiolabeled BMP-7 ((125)I-BMP-7) was injected into the subacromial bursa in the (125)I-BMP-7 group, whereas a GHS impregnated with (125)I-BMP-7 was implanted on the tendon attached to the tendon-to-bone insertion in the (125)I-BMP-7+GHS group. Levels of (125)I-BMP-7 in the tendon-to-bone insertion were assessed at 1, 3, 7, 14, and 21 postoperative days. The BMP-7 concentrations were significantly higher in the (125)I-BMP-7+GHS group than in the (125)I-BMP-7 group. Next, the bilateral supraspinatus tendons were resected and sutured to the greater tuberosity of the humerus using the Mason-Allen technique. Treatment groups were created as follows: either phosphate-buffered saline (PBS) or BMP-7 was injected into the subacromial bursa in the PBS and BMP-7 groups, whereas a GHS impregnated with either PBS or BMP-7 was implanted on the repaired tendon attached to the tendon-to-bone insertion in the PBS+GHS and BMP-7+GHS groups. The resected specimens were stained at 2, 4, and 8 postoperative weeks with hematoxylin and eosin as well as Safranin O, and tissue repair was evaluated histologically by using the tendon-to-bone maturing score. Tissue repair was assessed biomechanically at 4 and 8 postoperative weeks. The BMP-7+GHS group at 8 postoperative weeks demonstrated a favorable cartilage matrix production and tendon orientation; moreover, the tendon-to-bone maturing score and the ultimate force-to-failure were the highest in this group. The ability of GHS to provide controlled release of various growth factors has been previously reported. We confirmed that the GHS releases BMP-7 in a sustained manner in the rat shoulder joint. At 8 postoperative weeks, the repaired tissue was mostly restored, both histologically and biomechanically, in the BMP-7+GHS group. We therefore conclude that the sustained release of BMP-7 from a GHS can stimulate rotator cuff repair.

Antimicrobial megaprostheses supported with iodine.

Deep infection associated with implants remains a serious complication of orthopedic surgery. We developed iodine coating for titanium implants. In this study, we performed a clinical trial of iodine-coated megaprostheses to evaluate its safety and antibacterial effects. Forty-seven patients with malignant bone tumor or pyogenic arthritis were treated using iodine-supported titanium megaprostheses between July 2008 and May 2013. The mean age was 53.6 years (range, 15-85 years). Twenty-six patients were males and 21 were females. The diagnoses included malignant bone tumor in 29 cases, infected total knee arthroplasty in 11 cases, chronic osteomyelitis due to pyogenic arthritis in six cases and loosening of total knee arthroplasty in one case. The iodine-supported implants used were 42 Kyocera Limb Salvage System and five KOBELCO K-MAX K-3. These megaprostheses were used to prevent infection in 21 patients, treat active infections in 26 patients. The mean follow-up period was 30.1 months (range, 8-50). Infection was prevented in 20 out of 21 patients. Only one patient had surgical site infection caused by Pseudomonas aeruginosa and was cured by intravenous administration of antibiotics alone without removal of the implant. In 26 treatment cases involving one- or two-stage revision surgery, infection subsided without any additional surgery. In all cases, there were no signs of infection at the time of the last follow-up. White blood cell and C-reactive protein levels returned to normal within four weeks after surgery. To confirm systemic effects of iodine, thyroid hormone levels in the blood were examined. Abnormalities of thyroid gland function were not detected. Loosening of the implants was not observed. Excellent bone ingrowth and ongrowth were found around iodine-supported megaprostheses. The iodine-supported titanium megaprostheses are highly effective and show promise for the prevention and treatment of infections in large bone defects. No cytotoxicity or adverse effects were detected with this treatment.

Evaluation of resorption and biocompatibility of collagen hemostats in the spinal epidural space.

BACKGROUND CONTEXT: Collagen hemostats have different characteristics depending on their properties and configuration. In vivo serial evaluation of local reactions because of placement of hemostats in the epidural space has not been reported. PURPOSE: This study compared the resorption and biocompatibility of two types of collagen hemostats placed in the epidural space. STUDY DESIGN: This in vivo study used experimental animals to evaluate collagen hemostats that were placed in the epidural space. METHODS: A ligamentum flavum resection model was created in Japanese white rabbits (n=65). A microfibrillar collagen hemostat (MCH group, n=5), cotton-type collagen hemostat (CCH group, n=5) that was chemically cross-linked, or no hemostat (control group, n=4) was placed in the spinal epidural space. For histologic evaluation, each group was euthanized 1, 2, 4, and 8 weeks postoperatively (PO), and hematoxylin-eosin and immunohistochemical (IHC) staining for inflammatory cytokines (tumor necrosis factor [TNF]-α, interleukin [IL]-6), cyclooxygenase (COX)-2, and macrophages (CD68) was performed. To evaluate exudate accumulation and the degree of inflammation in the epidural space, magnetic resonance imaging at 7.04 T was serially performed in each group (n=3) under anesthesia and sedation. RESULTS: The collagen hemostats in both groups were reabsorbed at 4 weeks PO. In the MCH group, there was inflammatory cell infiltration and granuloma formation around the hemostat, TNF-α-positive cells were seen up to 1 week, and IL-6-, COX-2-, and CD68-positive cells were seen at all evaluation times. In the CCH group, no inflammatory cell infiltration around the hemostat was observed, and IHC staining showed no positive cells at 4 weeks PO and later. T2*-weighted MR images showed significantly higher mean signal intensity of the epidural space in the MCH group than in the CCH group but only at 1 week PO (p<.05). CONCLUSIONS: Resorption of both hemostats was similar. In the MCH group, there was intense tissue inflammation around the hemostatic material, and MR images showed high signal intensity because of exudate accumulation in the epidural space. This indicated a strong foreign-body reaction to the MCH, thus demonstrating a difference in biocompatibility with the CCH.