N-cadherin regulates spatially polarized signals through distinct p120ctn and ß-catenin-dependent signalling pathways.

The spatial distribution of molecular signals within cells is crucial for cellular functions. Here, as a model to study the polarized spatial distribution of molecular activities, we used cells on micropatterned strips of fibronectin with one end free and the other end contacting a neighbouring cell. Phosphoinositide 3-kinase and the small GTPase Rac display greater activity at the free end, whereas myosin II light chain and actin filaments are enriched near the intercellular junction. Phosphoinositide 3-kinase and Rac polarization depend specifically on the N-cadherin-p120 catenin complex, whereas myosin II light chain and actin filament polarization depend on the N-cadherin-ß-catenin complex. Integrins promote high phosphoinositide 3-kinase/Rac activities at the free end, and the N-cadherin-p120 catenin complex excludes integrin α5 at the junctions to suppress local phosphoinositide 3-kinase and Rac activity. We hence conclude that N-cadherin couples with distinct effectors to polarize phosphoinositide 3-kinase/Rac and myosin II light chain/actin filaments in migrating cells.

Dissociation of polyethylene insert from the tibial baseplate following revision total knee arthroplasty.

Dissociation of a modular tibial insert from the metal baseplate is a rare complication after revision total knee arthroplasty. We herein report an unusual presentation of a polyethylene insert failure that occurred in a posterior-stabilized constrained total knee arthroplasty. The polyethylene insert was posteriorly displaced, which has never been reported in the literature. The assumed mechanism is disengagement of the locking screw after repetitive motion. During knee full extension while standing from a chair, a sudden downward force on the anterior half of the insert caused posterior lift-off of the insert from the tibial baseplate and promoted a sliding force to push the insert posterior when the locking mechanism failed. This unique complication in a fully constrained posterior-stabilized implant should be considered as a cause for implant failure.

Treatment of diabetic foot infection with hyperbaric oxygen therapy.

BACKGROUND: This study was performed to evaluate the effectiveness of hyperbaric oxygen therapy (HBOT) in the treatment of the infected diabetic foot. METHODS: Forty-two patients with 44 infected diabetic feet receiving HBOT were divided into two groups. One group of 21 patients with 21 feet received <10 sessions of HBOT. The other 21 patients with 23 feet received >10 sessions of HBOT. RESULTS: In patients who received <10 sessions of HBOT, seven patients achieved satisfactory wound healing. Feet were preserved in 33.3%. In patients with >10 sessions of HBOT, 16 patients with 18 feet achieved good wound healing. Of these patients, 78.3% preserved their feet. This group of patients received an average of 22.8 HBOT treatments. CONCLUSIONS: Adjunctive HBOT has a positive effect on wound healing in diabetic foot with infection. The effect of HBOT seems dose dependent because the amputation rate is decreased in patients who receive adequate HBOT.

Anterior-inferior plating of middle-third fractures of the clavicle.

INTRODUCTION: Various techniques have been reported for the treatment of middle-third clavicle (collar bone) fractures. This prospective study was conducted to evaluate the results of anterior-inferior plating using a 3.5-mm reconstruction plate for the treatment of middle-third clavicle fractures. PATIENTS AND METHODS: Twenty-six patients with middle-third clavicle fractures were treated with anterior-inferior plating. The indications for surgery included complete displacement, severe comminution, and marked shortening of the clavicle (>2 cm). RESULTS: The mean time to union was 14 weeks (range 8-20 weeks). At the time of latest follow-up, all of the patients had returned to their pre-injury activity level. The plates were removed in ten patients after the fractures healed. No patients required plate removal due to implant-related problems. CONCLUSION: Anterior-inferior plating is an effective treatment modality for middle-third clavicle fractures, with few complications and early return of shoulder function. The procedure provides stable fixation, avoids risk to vital structures below the clavicle, and is associated with a low rate of implant-prominence problems.

Treatment of distal radius fractures with percutaneous pinning and pin-in-plaster.

This article describes a modified technique that combines percutaneous pinning and casting. A prospective study was conducted on 54 patients with distal radius fracture who were treated with percutaneous Kirschner wire (K-wire) fixation and pin-in-plaster technique. The surgical indications of this technique included displaced extra-articular fracture, intra-articular fracture without significant comminution, and articular step-off less than 2 mm. The average radial height was 10.96 mm, and the volar tilt was 3.97 degrees on immediate postoperative radiographs. Upon removal of pin-in-plaster and percutaneous K-wires, the average radial height was 9.92 mm, and the volar tilt was 3.93 degrees . Bony union was achieved in all patients; the satisfaction rate was 90.7%. Pin-in-plaster technique is effective for maintaining reduction during bone healing. The procedure provides the ability to achieve anatomic reduction and then maintains this reduction through an adequate method of immobilization.

Management of nonunion associated with broken intramedullary nail of the femur.

This study analyzed 14 patients with 17 broken intramedullary nails for the treatment of femoral fractures. Average distance from the fracture site was 7.9 cm in cases in which nail breakage occurred at the junction between the cylindrical and cloverleaf portions and 6.4 cm in cases in which nail breakage occurred at the screw hole. Eleven patients with 14 broken nails were treated with exchange nailing and bone grafting, 2 were treated with plating and bone grafting, and 1 was treated with extracorporeal shock wave therapy. Nonunion or delayed union is the main cause of nail breakage. Exchange nailing with bone grafting is a safe and effective method of treatment for a broken intramedullary nail with nonunion.

Total hip arthroplasty for primary septic arthritis of the hip in adults.

Two-stage total hip arthroplasties (THA) performed after primary septic arthritis of hip were studied to evaluate the surgical outcomes and complications. Of 28 cases, the reinfection rate was 14% and complication rate was 36%. At an average follow-up period of 77 months, the outcome in 22 patients (79%) was rated as good or excellent, 4 as fair, and 2 as poor. Leg length discrepancy improved from a preoperative mean of 2.89 cm to a postoperative mean of 0.61 cm. Despite a higher complication rate, two-stage THA was still deemed a worthy procedure because hip function was significantly improved in patients with primary septic arthritis of the hip.

Surgical treatment of fractures of the greater trochanter associated with osteolytic lesions. Surgical technique.

BACKGROUND: A fracture of the greater trochanter through an osteolytic lesion may occur as a late complication after total hip arthroplasty. The optimal treatment for this difficult complication remains controversial. We have treated this problem with internal fixation and allogeneic bone-grafting at the time of revision of a loose acetabular component. METHODS: We retrospectively reviewed the results of treatment of a fracture through an osteolytic lesion of the greater trochanter in nineteen patients seen from 1996 to 2002. All fractures were treated with morselized allogeneic bone grafts and wire fixation at the time of revision of a failed acetabular component. Postoperative care included the use of an abduction orthosis and protected weight-bearing for at least three months. Follow-up of all patients consisted of radiographic examinations and clinical evaluation with use of the Harris hip score. RESULTS: At an average duration of 3.8 years after the revision, eighteen of the nineteen fractures had healed. The average time to healing was five months. The one treatment failure occurred in a patient who did not comply with the use of an abduction orthosis. The average Harris hip score for all patients improved from 32.5 points preoperatively to 91.2 points at the time of the latest follow-up. Polyethylene wear and recurrent osteolysis of the greater trochanter was noted in one hip at the eight-year follow-up examination. CONCLUSIONS: Fractures of the greater trochanter associated with osteolytic lesions can be effectively treated with open reduction, internal fixation with wire, and allogeneic bone-grafting.

Pathogenesis of partial tear of the rotator cuff: a clinical and pathologic study.

This prospective study investigated the clinical and pathologic results in 66 patients with partial tears of the rotator cuff from January 1996 to December 1998. The pathologic change in the rotator cuff was graded from the magnetic resonance images by using the criteria described by Zlatkin and Iannotti. A modified grading system from Ozaki and Panni was used for pathologic grading of the anterior acromion. The functional score of Constant and Murley was used for clinical assessment. The pathologic change in the rotator cuff revealed by the magnetic resonance imaging study was more severe in patients with articular side tears compared with patients who had bursal side tears. On the contrary, the pathologic changes in the acromion were significantly milder in patients with articular side tears compared with bursal side tears. These observations indicate that articular side tears of the rotator cuff are mainly associated with intrinsic pathologic changes of the rotator cuff, whereas bursal side tears are associated with subacromial impingement on an underlying milder pathologic change of the rotator cuff.

Surgical treatment of fractures of the greater trochanter associated with osteolytic lesions.

BACKGROUND: A fracture of the greater trochanter through an osteolytic lesion may occur as a late complication after total hip arthroplasty. The optimal treatment for this difficult complication remains controversial. We have treated this problem with internal fixation and allogeneic bone-grafting at the time of revision of a loose acetabular component. METHODS: We retrospectively reviewed the results of treatment of a fracture through an osteolytic lesion of the greater trochanter in nineteen patients seen from 1996 to 2002. All fractures were treated with morselized allogeneic bone grafts and wire fixation at the time of revision of a failed acetabular component. Postoperative care included the use of an abduction orthosis and protected weight-bearing for at least three months. Follow-up of all patients consisted of radiographic examinations and clinical evaluation with use of the Harris hip score. RESULTS: At an average duration of 3.8 years after the revision, eighteen of the nineteen fractures had healed. The average time to healing was five months. The one treatment failure occurred in a patient who did not comply with the use of an abduction orthosis. The average Harris hip score for all patients improved from 32.5 points preoperatively to 91.2 points at the time of the latest follow-up. Polyethylene wear and recurrent osteolysis of the greater trochanter was noted in one hip at the eight-year follow-up examination. CONCLUSIONS: Fractures of the greater trochanter associated with osteolytic lesions can be effectively treated with open reduction, internal fixation with wire, and allogeneic bone-grafting.

Results of vancomycin-impregnated cancellous bone grafting for infected tibial nonunion.

INTRODUCTION: Bone grafting plays a critical role in promoting bone healing in infected nonunion, although recurrent infection is of concern. Cancellous bone grafting as an antibiotic delivery system has been reported as an effective method to combat infections. In this study, we report the clinical results of vancomycin-impregnated cancellous bone grafting for the treatment of infected tibial nonunion. MATERIALS AND METHODS: Between January 1996 and March 2001, 18 patients with infected tibial nonunion treated with vancomycin-impregnated cancellous bone grafting were available for follow-up. According to the Cierny-Mader classification, all patients belonged to type IVA and IVB osteomyelitis. Adequate debridement, stabilization with external fixation, and staged vancomycin-impregnated cancellous bone grafting were used in all patients. Regular clinical and radiographic follow-ups were conducted. RESULTS: Infection control was obtained in all 18 patients with a 100% infection arrest rate. Bone union was achieved in 13 of 18 patients at an average of 5.8 months. Bone union was obtained subsequently in the remaining five patients after closed nailing in four, and plating and bone grafting in one patient. Radiographs showed good consolidation and hypertrophy of grafted bone at an average follow-up of 48 months. CONCLUSION: We conclude that vancomycin-impregnated cancellous bone grafting is a safe method for the treatment of infected tibial nonunion.

Femoral head preservation in non-united femoral neck fracture and head osteonecrosis in Cushing's disease.

There have been few reports associating avascular necrosis of bone with Cushing's disease. Patients with Cushing's disease and avascular necrosis of the femoral head usually receive total hip arthroplasty. However, hip prosthetic replacement in younger patients has been criticized due to a high incidence of component loosening. We report a case of successful femoral head preservation in non-united femoral neck fracture and head osteonecrosis in a 14-year-old girl with Cushing's disease (adrenocorticotropic hormone-secreting pituitary adenoma) who developed avascular necrosis of the right femoral head and pathologic fracture of the right femoral neck 2 years after the onset of hypercortisolism. Subtrochanteric valgus osteotomy was performed to preserve the femoral head after successful transsphenoidal surgery to remove pituitary microadenoma. At follow-up 10 years after the osteotomy, the femoral head had revascularized and the femoral neck fracture were united with much improvement of hip function. Dual energy X-ray absorptiometry scan of the right hip showed +0.86 SD from the normal bone densitometry. Aggressive femoral head preservation may be an effective alternative to treat this rare situation in a teenager.

Results of chronic osteomyelitis of the femur treated with hyperbaric oxygen: a preliminary report.

BACKGROUND: Although only a few studies have shown the effectiveness, hyperbaric oxygen (HBO) therapy has been used as an adjunct in the management of chronic osteomyelitis in many hospitals in Taiwan. This retrospective study investigated the clinical results of HBO therapy for chronic refractory osteomyelitis of the femur. METHODS: From December 1999 through May 2002, 13 patients with chronic refractory osteomyelitis of the femur were treated with adjunctive HBO. The most common infecting microorganism was Staphylococcus aureus. All cases were classified as type III or IV osteomyelitis according to the Cierny-Mader classification. Adequate surgical debridement and parenteral antibiotic treatment were performed. The average number of operations before HBO therapy was 4.6 times. HBO therapy at 2.5 atmospheres absolute for 120 minutes was administered for 5 days per week in all patients for an average of 50 days. The average number of HBO treatments was 32.2 times. The average follow-up period was 22 months, ranging from 12 to 42 months. RESULTS: Complete eradication of infection with no recurrence of infection was noted in 12 of the 13 patients. One patient failed to respond to the treatment. The success rate of the treatment regimen was 92%. There were no HBO therapy related complications. CONCLUSION: Hyperbaric oxygen therapy is an effective and safe adjunctive therapy for the management of chronic refractory osteomyelitis of the femur provided that patients had received adequate surgical debridement and appropriate antibiotic treatment.

Infection after intramedullary nailing of the femur.

BACKGROUND: The management of infection after intramedullary nailing of the femoral shaft fracture remains a challenge to orthopedic surgeons. The dilemma confronting surgeons concerns the removal or retention of the nail in the presence of infection. METHODS: The authors treated 23 infections after intramedullary nailing for femoral fractures. All fractures were unhealed at presentation. All patients were followed for at least 1 year after the infection. Acute infection occurred in 13 patients, subacute infection in 5, and chronic infection in 5. The patients were divided into two groups on the basis of the method of the initial treatment. In group I (12 patients), the intramedullary nails were retained, and there were 11 men and 1 woman, with an average age of 36 years (range, 15-55 years). In group II (11 patients), the nails were removed at the time of debridement and the fractures were stabilized with external fixation, and there were nine men and two women, with an average age of 44 years (range, 25-69 years). RESULTS: In group I, all fractures healed within an average period of 9 months (range, 5-15 months) after surgical debridement. There was no recurrence of infection at an average follow-up of 25 months (range, 12-76 months). In group II, seven fractures healed within an average of 10 months (range, 4-24 months) after treatment. At an average follow-up of 33.8 months (range, 12-79 months), infected nonunion was noted in two patients. More complications occurred in group II patients in comparison with group I patients. Limited range of motion of the knee joint was usually encountered if a fracture was stabilized with external fixation for a prolonged period of time. CONCLUSION: Retention of the intramedullary nail is performed if the fixation is stable and the infection is under control. External fixation is most suitable for uncontrollable osteomyelitis or infected nonunion. Staged bone grafting is usually necessary when a bone defect is present.

Hyperbaric oxygen therapy in the treatment of chronic refractory osteomyelitis: a preliminary report.

BACKGROUND: Hyperbaric oxygen (HBO) has been proven to enhance bone and soft tissue healing in ischemic tissue in vitro and in vivo studies. Although only a few reports have been proven using controlled studies, this treatment modality remains encouraging for chronic refractory osteomyelitis. In this retrospective study, we reported the clinical results of HBO therapy for chronic refractory osteomyelitis. METHODS: From January through August 2000, 14 patients with chronic refractory osteomyelitis of the tibias treated with HBO were available for follow-up examination. According to the Cierny-Mader classification, all patients were classified as type III or IV osteomyelitis. Adequate debridement and parenteral antibiotic treatment in conjunction with HBO therapy at 2.5 atmospheres absolute for 120 minutes, and 5 days per week regimen was used in all patients. The patients were followed-up for an average of 15 months after completion of HBO therapy. RESULTS: The most common infecting microorganism was Staphylococcus aureus. Mixed infections were usually found in patients with open fractures. The average number of operations before HBO therapy was 5.4 including soft tissue reconstruction in 11 patients. The average number of HBO treatments was 33.6 times. There were no HBO related complications. No recurrence of infection was noted in 11 patients, which resulted in a success rate of 79%. CONCLUSIONS: Hyperbaric oxygen therapy is effective and safe for chronic refractory osteomyelitis provided that patients had received appropriate medical and surgical management.

Results of curettage and high-speed burring for chondroblastoma of the bone.

BACKGROUND: Chondroblastomas of the bone are rare lesions. Most of these lesions can be successfully treated by curettage and bone grafting. However, a considerable rate of recurrence has been reported, especially in aggressive lesions. The purpose of this study was to report the results of 10 cases of chondroblastomas of the bone treated with curettage and high-speed burring. METHODS: Ten patients with histologically confirmed chondroblastoma of the bone were treated with curettage and high-speed burring between October 1991 and August 2000. There were 7 men and 3 women with an average age of 18.9 (range, 12 to 30) years. Radiographically, 3 were classified as having aggressive lesions, and 7 were classified as having non-aggressive ones. For treatment, 8 of them had defects packed with either bone grafts or bone substitutes; 1 defect was packed with bone cement; and the other was left alone because the lesion was small. RESULTS: At an average follow-up period of 62 (range, 8 to 112) months, all patients had painless, normal function of the affected limb without local recurrence or distant metastasis. Complete healing of the lesion was seen in 8 patients including the one without a bone graft. The lesion in 1 patient who had received bone cement remained unchanged radiographically. One patient experienced incomplete healing of the lesion, which was caused by inadequate packing of the bone substitute. CONCLUSION: Curettage and high-speed burring represent an effective method for the treatment of chondroblastoma of the bone whether in the non-aggressive or aggressive stage.

Premature closure of the physeal plate after treatment of a slipped capital femoral epiphysis.

BACKGROUND: Treatment of a slipped capital femoral epiphysis (SCFE) should stabilize the epiphysis and prevent complications. Attempting to obtain physeal closure is still controversial. The purpose of this study was to evaluate the clinical results and complications after treatment of SCFE. METHODS: From 1989 to 2000, 12 patients (14 hips) underwent pinning for treatment of SCFE. For acute and acute-on-chronic slippage, longitudinal traction was attempted for reduction. Patients with chronic slippage received fixation in situ. All patients were available for follow-up for an average of 63 months. RESULTS: Nine of the 14 hips had excellent or good functional results, and 5 had fair results. One hip developed avascular necrosis of the femoral head with a fair result. There was no chondrolysis or osteoarthritis of the joint at the most recent follow-up. Physeal closure in 9 hips occurred at an average of 16 months. The change in articulotrochanteric distance averaged 5.4 mm. CONCLUSION: Although most functional results were not adversely influenced after premature closure of the physeal plate of consideration should be given to the device, such as a dynamic screw, that stabilizes the epiphysis and prevents premature physeal closure in patients who have significant growth potential. To understand the influence of growth disturbance of the proximal femur and the effect of dynamic screw fixation, long-term follow-up is mandatory.