Shunichi Toki

Local administration of zoledronic acid for giant cell tumor of bone.

Giant cell tumor of bone is a locally aggressive tumor with a high local recurrence rate. Several adjuvant therapies have been employed to reduce the recurrence rate, but their effectiveness remains controversial. The authors attempted local administration of zoledronic acid, a nitrogen-containing bisphosphonate that strongly inhibits bone resorption, as an adjuvant treatment for histologically proven giant cell tumor of bone in 5 patients at their institution. After biopsy, 4 patients were treated with local administration of zoledronic acid with artificial bone and 1 was treated with zoledronic acid without artificial bone. Histologic response to the treatment was evaluated with surgically resected specimens. The 4 patients treated with artificial bone showed local control, with histologic tumor necrosis rates of 90%, 90%, 50%, and 10%. Magnetic resonance imaging showed poor gadolinium enhancement, and histologic examination after local zoledronic acid treatment showed tumor necrosis. One patient without artificial bone showed no histologic tumor necrosis and had local recurrence in soft tissue 18 months after tumor resection. A 3-week waiting period between biopsy and zoledronic acid treatment appears reasonable from the histological study. Complication of this therapy was delayed wound healing and it occurred in 2 cases. Taken together, this case series suggests that local administration of zoledronic acid with artificial bone is a potential adjuvant therapy for giant cell tumor of bone. On the other hand, effective local administration of zoledronic acid requires some bone matrix, including artificial bone. Campanaccis grading is important for predicting the effect of local administration of zoledronic acid.

Intrapelvic Migration of the Lag Screw in Intramedullary Nailing

Internal fixation with intramedullary devices has gained popularity for the treatment of intertrochanteric femoral fractures, which are common injuries in the elderly. The most common complications are lag screw cut out from the femoral head and femoral fracture at the distal tip of the nail. We report here a rare complication of postoperative lag screw migration into the pelvis with no trauma. The patient was subsequently treated with lag screw removal and revision surgery with total hip arthroplasty. This case demonstrated that optimal fracture reduction and positioning of the lag screw are the most important surgical steps for decreasing the risk of medial migration of the lag screw. Furthermore, to prevent complications, careful attention should be paid to subsequent steps such as precise insertion of the set screw.

The Pullout Strength of Pedicle Screws Following Redirection After Lateral Wall Breach or End-plate Breach.

Study Design. Using fresh cadavers, the biomechanical testing were used to examine the pullout strength of each pedicle screw. Objective. The aim of this study was to evaluate pullout strength of (1) a redirected pedicle screw following lateral wall breach; (2) a redirected pedicle screw following end-plate breach; and (3) a pedicle without redirection after end-plate breach without redirection. Summary of Background Data. Screw malposition, such as lateral wall breach or end-plate breach, is one of the main pitfalls of inserting pedicle screws. Methods. From 17 fresh spines, 54 vertebrae were harvested. In each vertebra on one pedicle, the screw was inserted correctly down the axis of the pedicle, while on the other pedicle, the screw was inserted to breach the lateral wall or the end-plate. The 18 pedicle screws that breached the lateral wall were then removed and redirected along the correct axis of the pedicle. The 18 pedicle screws that breached the end-plate were removed and redirected along the correct axis of the pedicle. The 18 other pedicle screws that had breached the end-plate were not removed. The pullout force of pedicle screws was measured. Results. First, the mean pullout strength for the redirected screws following lateral wall breach was 24.0% less as compared with the correctly aligned screws. Second, the mean pullout strength for the redirected screws following end-plate breach was 23.3% less as compared with the correctly aligned screws. Third, the mean pullout strength for the pedicle screws end-plate breach was 7.6% less as compared with the correctly aligned screws. Conclusion. The pullout strength of redirected pedicle screws after either a lateral pedicle breach or end-plate breach is significantly less than the pullout strength of correctly aligned screw. A pedicle screw that is not redirected after end-plate breach is weaker than a pedicle screw correctly aligned; however, the difference is not significant. Level of Evidence: N/A

Complete spontaneous regression of a subpubic cartilaginous cyst: a case report

Subpubic cartilaginous cyst was recently reported as a rare degenerative mass on the pubic symphysis. We report here a 59-year-old woman who presented with a vulvar mass that showed complete spontaneous regression 48 months after the initial visit. Treatment was only wearing brace. This is the first report of complete spontaneous regression of a subpubic cartilaginous cyst. In the case of small subpubic cyst, observation and follow-up alone may be sufficient. J. Med. Invest. 63: 319-322, August, 2016.

The Posterior Condylar Cartilage Affects Rotational Alignment of the Femoral Component in Varus Knee Osteoarthritis

Rotational alignment of the femoral component in total knee arthroplasty (TKA) is important for patellar tracking and ligament balance. Preoperative planning based on radiography might have a potential risk for over-rotation because these X-ray based measurements can not detect asymmetric cartilage wear on posterior condyle. The purpose of this study is to evaluate the effect of the posterior condylar cartilage of varus osteoarthritic knee on rotational alignment of the femoral component in TKA. We established two different condylar twist angles (CTA) from intraoperative multiplanar reconstruction (MPR) images and intraoperative information of navigation system. The CTA measured by a navigation system that includes the cartilage (4.8±2.0°) was smaller than those measured by MPR images, which does not include the cartilage (6.6±2.1°) (p<0.05). The difference between these two angles that corresponds to the remaining posterior condylar cartilage was 1.7±1.2°. This result demonstrated that the posterior condylar cartilage might lead to over-rotational of the femoral component in varus osteoarthritic knee. Therefore, when determining rotational alignment of the femoral component, surgeons should consider the effect of the remaining posterior condylar cartilage to avoid the over-rotation of the femoral component, especially in severe varus knees. J. Med. Invest. 64: 24-29, February, 2016.

Fibroma of tendon sheath on the medial side of the knee: a case report

Fibroma of tendon sheath, which is a benign soft tissue tumor, primarily affects the finger, hand, or wrist. It rarely involves the knee and only a few cases appear in the literature. Here, we report a case of fibroma of tendon sheath on the medial side of the knee, in a previously hardly reported location, and provide detailed imaging and histological findings. A 54-year-old man presented with his right knee pain and a palpable mass that had developed 3 months earlier. Magnetic resonance imaging showed isointensity in the soft tissue tumor on T1-weighted images, variable intensity on T2-weighted images, and contrast enhancement. The specimen obtained by needle biopsy showed no histological findings of malignancy. Marginal resection was performed and the microscopic diagnosis was fibroma of tendon sheath. Since fibroma of tendon sheath is relatively rare, the radiological feature is not specific, and a rate of local recurrence following excision is high, careful diagnosis, surgical treatment and long-term follow-up are necessary. J. Med. Invest. 64: 173-176, February, 2017.

Delayed Diagnosis of Primary Bone and Soft Tissue Tumors Initially Treated as Degenerative Spinal Disorders

Background Symptoms of primary bone and soft tissue tumors located in the trunk mimic those of degenerative spinal disorders such as low back pain or pain or numbness of the legs. Due to their rarity, especially in sarcoma located in the trunk, diagnosis is sometimes delayed. Methods A retrospective review was performed of the records of 383 patients with primary bone and soft tissue tumors who visit our out patient clinic from 2011 to 2013 at a single institution. Patients with delayed diagnosis of primary bone and soft tissue tumors initially treated as degenerative spinal disorders for more than 2 months were identified. Results Of the 383 patients, 5 (1.3%) were initially diagnosed as having degenerative spinal disorders. All 5 patients had bone or soft tissue tumors in the lumbar spine or pelvis. Three patients had a malignant tumor (osteosarcoma, chondrosarcoma, or small round cell sarcoma) at the progressive stage, and 1 died of lung metastasis. Two patients had a benign tumor (aneurysmal bone cyst or simple bone cyst). Conclusions Our findings suggest that when low back pain and leg pain are refractory to conservative treatment, further radiological examination should be conducted. J. Med. Invest. 63: 274-277, August, 2016.

Pigmented villonodular synovitis of the knee joint in a 5-year-old girl treated with combined open and arthroscopic surgery: a case report.

Pigmented villonodular synovitis is an extremely rare disease in skeletally immature patients. Erosive destruction of the involved joint leads to early arthritis, and its high recurrence rate makes treatment challenging. Multiple surgical approaches exist, but it is unclear as to which among them achieves the lowest possible recurrence rate and morbidity. We report the case of a 5-year-old girl with left knee pain and swelling who was diagnosed with diffuse pigmented villonodular synovitis of the left knee based on MRI findings. Combined open and arthroscopic surgery was performed to completely remove the tumor. Postoperative histopathological examination confirmed the diagnosis of diffuse pigmented villonodular synovitis. The postoperative course was uneventful, with a gradual improvement in symptoms. There were no signs of recurrence on postoperative MRI performed at the 8-month follow-up, with neither knee pain nor limitation of range of motion. The favorable outcome in this case suggests that combined open and arthroscopic surgery may be an effective method for treating pigmented villonodular synovitis in skeletally immature patients.

Failure rates of Asian-type anatomic medullary locking stemmed metal-on-metal total hip replacement: A cause for adverse tissue reactions to metal debris (ARMD)

BACKGROUND Adverse tissue reaction to metal debris (ARMD) as a secondary complication of Metal-on-metal total hip replacement (MoM THR) has been of concern. We have been performing cementless MoM THR using an Asian-type anatomic medullary locking (AML) stem. The purpose of this study is to examine the incident rate of ARMD, and the implant survival rate. METHODS The study included 187 patients (211 hip joints) who underwent MoM THR between February 2007 and November 2009 at our hospital and who were followed up for a minimum of 6 years. The cases included 174 female joints and 37 male joints. The average age at the time of surgery was 68.4 years. The average postoperative follow-up period was 87.5 months. RESULTS ARMD was observed in 23 joints postoperatively, and the incidence rate was 10.9%. Most of the instances occurred within the first 30 months postoperatively. Revision surgery was performed for 14 joints after conservative treatment failed, and we changed the bearing surface. During the intraoperative observation, black-colored deposition of metal debris on the head-neck junction was observed in 13 cases. Kaplan-Meier analysis using the replacement surgery as the end point showed that this implant has a survival rate of 93.8% 7 years after the primary surgery. CONCLUSIONS We conclude that the major cause of failure of Asian-type AML stemmed MoM THR is likely the breakage of the fixation between the taper neck and metal head at the head-neck junction.

Symptomatic Os Intercuneiform: A Case Report

We encountered a case of an accessory bone in the foot in the distal portion of the tarsal navicular and the proximal portion of the intermediate cuneiform, namely an os intercuneiform. The patient presented with a history of pain on the dorsal aspect of the left foot, with tenderness and swelling. Perioperative findings revealed a synfibrotic connection between the accessory bone and the navicular and intermediate cuneiform. After unsuccessful conservative treatment, the accessory bone was excised, leading to postoperative symptomatic relief.