Silk and collagen scaffolds for tendon reconstruction.

In this study, silk thread (Bombyx mori) was braided to a tube-like shape and sericin was removed from the silk tube. Thereafter, collagen/chondroitin-6-sulfate solution was poured into the silk tube, and the lyophilization process was performed. To assess the inflammatory response in vivo, raw silk and sericin-free silk tubes were implanted in the subcutaneous layer of mice. After 10 days of in vivo implantation, mild inflammatory responses were observed around the sericin-free silk tubes, and severe inflammation with the presence of neutrophils and macrophages was observed around the raw silk tubes. At 24 weeks post implantation, the regenerated tendon had a thick, cylindrical, grayish fibrous structure and a shiny white appearance, similar to that of the native tendon in the rabbit model of tendon defect. The average tensile strength of the native tendons was 220 ± 20 N, whereas the average tensile strength of the regenerated tendons was 167 ± 30 N and the diameter of the regenerated tendon (3 ± 0.2 mm) was similar to that of the native tendons (4 ± 0.3 mm). Histologically, the regenerated tendon resembled the native tendon, and all the regenerated tissues showed organized bundles of crimped fibers. Masson trichrome staining was performed for detecting collagen synthesis, and it showed that the artificial tendon was replaced by new collagen fibers and extracellular matrix. However, the regenerated tendon showed fibrosis to a certain degree. In conclusion, the artificial tendon, comprising a braided silk tube and lyophilized collagen sponge, was optimal for tendon reconstruction. Thus, this study showed an improved regeneration of neo-tendon tissues, which have the structure and tensile strength of the native tendon, with the use of the combination of collagen and silk scaffold.

Secondary aneurysmal bone cystic change of the chondroblastoma, mistaken for a primary aneurysmal bone cyst in the patella.

A 29-year-old woman complained of a 3-month history of left knee pain without trauma history. X-ray showed a well-defined osteolytic lesion with a sclerotic margin in the patella and magnetic resonance imaging showed T1-low and T2-high signal intensity with different fluid level. Our impression was an aneurysmal bone cyst. At surgery, the lesion was a blood-filled cystic cavity, surrounded by a gray or brownish tissue. Hemorrhagic soft tissues with recognizable bone fragments were observed. Curettage and autogenous bone graft was done. Microscopically, sheets of tumor cells were intermingled with some areas of eosinophilic chondroid matrix. The tumor cells showed oval-shaped nuclei with moderate eosinophilic cytoplasm. Several multinucleated giant cells and blood filled cystic cavities were observed. The final diagnosis was a chondroblastoma with a secondary aneurysmal bone cyst. At the post-operative 1.5-year follow-up, grafted bones were well incorporated radiographically and there were no recurrent evidence or any other abnormal symptoms.

Avulsion fracture of the calcaneal tuberosity: classification and its characteristics.

BACKGROUND: Not much is known regarding avulsion fractures of the calcaneal tuberosity. We propose a modified classification scheme that presents the four types of calcaneal avulsion fracture as described by surgical and magnetic resonance imaging (MRI) findings, and evaluation of their specific features. METHODS: Out of 764 cases of calcaneal fractures, we examined 20 cases (2.6%) that involved the tuberosity of the calcaneus. Each case was classified depending on the avulsed fracture patterns as follows; type I is a 'simple extra-articular avulsion' fracture, type II is the 'beak' fracture, type III is an infrabursal avulsion fracture from the middle third of the posterior tuberosity, and finally in type IV there is the 'beak', but a small triangular fragment is separated from the upper border of the tuberosity. We examined the features of each avulsed type according to several criteria including patient age, gender, anatomical variances of the Achilles tendon, the fibers involved and the mechanism of injury. RESULTS: The type I fracture (8/20 cases) was the most common and likely to occur in elderly women. However, in other types, they were more common in relatively younger male patients. Type I were usually caused due to an accidental trip causing a fall by the patient. However, the dominant cause of type II (5/20 cases) fractures a direct blow or hit directly to the bone. Type III (4/20 cases) and IV (3/20 cases) fractures were likely to occur due to falling. All fibers within the Achilles tendon are involved in both type I and II fractures. However, only the superficial fibers are involved in type III fractures, whereas the deep fibers are involved in type IV fractures. CONCLUSIONS: The avulsion patterns of the calcaneal tuberosity fractures are the result of several factors including the bony density level, the mechanism of injury and the fibers of the Achilles tendon that transmit the force. Accurate diagnosis of type III and IV is dependant on MRI technology to confirm the specific location of the injury and provide proper patient treatment therapeutics.

Average 10.1-year follow-up of cementless total knee arthroplasty in patients with rheumatoid arthritis.

BACKGROUND: Total knee arthroplasty (TKA) using a cemented technique has been recommended in patients with rheumatoid arthritis owing to the initial stability of the fixation and long-term durability of the components; however, similar long-term follow-up results have been reported in patients who have undergone cementless TKA. The purpose of this study was to evaluate the radiologic and clinical outcomes of cementless TKA in patients with rheumatoid arthritis. METHODS: We enrolled patients undergoing cementless TKA from March 1990 to February 2000. Clinical and radiologic evaluations were performed using the Knee Society clinical rating system and radiographic evaluation and scoring system. RESULTS: We included the cases of 112 patients who underwent 179 cementless TKA procedures in our analysis. Their mean age was 62.3 years, and the mean follow-up period was 10.1 years. The final survival rate was 0.968 at the 15.5-year follow-up. Regarding radiologic results after surgery, the mean total valgus angle was 6.7°, the mean femoral flexion angle was 97.5° and the mean tibial angle was 89.2° on the anteroposterior radiographs. On the lateral films, the mean femoral flexion angle was 1.6° and the mean tibial angle was 89.2°. At the last follow-up, the mean total valgus angle was 6.5°, the mean femoral flexion angle was 97.4° and the mean tibial angle was 89.1°, as seen on the anteroposterior view. On the lateral views, the mean femoral flexion angle was 1.4° and the mean tibial angle was 89.0°. Regarding the clinical outcome, the mean knee score and function score on the Knee Society clinical rating system were also enhanced from 47.5 and 43.6, respectively, before the operation to 91.2 and 82.3, respectively, at the last follow-up. CONCLUSION: On radiologic and clinical follow-up of cementless TKA for patients with rheumatoid arthritis, there were no serious complications, and the results of the operation were satisfactory with improvement in range of motion and clinical symptoms.

Ankle deformity secondary to acquired fibular segmental defect in children.

BACKGROUND: The authors report the long-term effect of acquired pseudoarthrosis of the fibula on ankle development in children during skeletal growth, and the results of a long-term follow-up of Langenskiold's supramalleolar synostosis to correct an ankle deformity induced by an acquired fibular segmental defect in children. METHODS: Since 1980, 19 children with acquired pseudoarthrosis of the fibula were treated and followed up for an average of 11 years. Pseudoarthrosis was the result of a fibulectomy for tumor surgery, osteomyelitis of the fibula and traumatic segmental loss of the fibula in 10, 6, and 3 cases, respectively. Initially, a Langenskiold's operation (in 4 cases) and fusion of the lateral malleolus to the distal tibial epiphysis (in 1 case) were performed, whereas only skeletal growth was monitored in the other 14 cases. After a mean follow-up of 11 years, the valgus deformity and external tibial torsion of the ankle joint associated with proximal migration of the lateral malleolus needed to be treated with a supramallolar osteotomy in 12 cases (63%). These ankle deformities were evaluated using the serial radiographs and limb length scintigraphs. RESULTS: In all cases, early closure of the lateral part of the distal tibial physis, upward migration of the lateral malleolus, unstable valgus deformity and external tibial torsion of the ankle joint developed during a mean follow-up of 11 years (range, 5 to 21 years). The mean valgus deformity and external tibial torsion of the ankle at the final follow-up were 15.2 degrees (range, 5 degrees to 35 degrees) and 10 degrees (range, 5 degrees to 12 degrees), respectively. In 12 cases (12/19, 63%), a supramalleolar corrective osteotomy was performed but three children had a recurrence requiring an additional supramalleolar corrective osteotomy 2-4 times. CONCLUSIONS: A valgus deformity and external tibial torsion are inevitable after acquired pseudoarthrosis of the fibula in children. Both Langenskiöld supramalleolar synostosis to prevent these ankle deformities and supramalleolar corrective osteotomy to correct them in children are effective initially. However, both procedures cannot maintain the permanent ankle stability during skeletal maturity. Therefore any type of prophylactic surgery should be carried out before epiphyseal closure of the distal tibia occurs, but the possibility of a recurrence of the ankle deformities and the need for final corrective surgery after skeletal maturity should be considered.