Yasuaki Tamaki

CT-based morphological assessment of the hip joint in Japanese patients: association with radiographic predictors of femoroacetabular impingement

AIMS Femoroacetabular impingement (FAI) has been highlighted and well documented primarily in Western countries and there are few large studies focused on FAI-related morphological assessment in Asian patients. We chose to investigate this subject. PATIENTS AND METHODS We assessed the morphology of the hip and the prevalence of radiographic FAI in Japanese patients by measuring predictors of FAI. We reviewed a total of 1178 hips in 695 men and 483 women with a mean age of 58.2 years (20 to 89) using CT images that had been obtained for reasons unrelated to symptoms from the hip. We measured the lateral centre edge angle, acetabular index, crossover sign, alpha angle and anterior femoral head-neck offset ratio. RESULTS A total of 441 hips (37.4%) had pincer-type deformity (41.7% men, 31.3% women) and 534 (45.3%) had cam-type deformity (54.4% men, 32.3% women). Moreover, 773 hips (65.6%) had at least one parameter that predisposes to FAI (74.0% men, 53.6% women) and 424 hips (36.0%) had two or more parameters (43.6% men, 25.0% women). CONCLUSION The prevalence of radiographic FAI was common in Japanese patients who are generally considered to have dysplastic hips. Cite this article: Bone Joint J 2016;98-B:1167-74.

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.

Incidence and clinical features of sacral insufficiency fracture in the emergency department

Introduction: A sacral insufficiency fracture (SIF) often manifests as low back pain or sciatica in the absence of any antecedent trauma. These fractures may be missed because of lack of appropriate imaging. The purpose of this study was to clarify the incidence and clinical features of SIF as well as the characteristic findings on magnetic resonance imaging (MRI) of the lumbar spine. Materials and methods: The study participants comprised 250 patients (132 male, 118 female; mean age 58.6 years) with pelvic trauma. SIF was identified on computed tomography or MRI. The incidence, initial symptoms, and time delay between the first visit and an accurate diagnosis of SIF were recorded. Results: We detected 11 cases of SIF. Initial symptoms of SIF were low back pain (36.4%), gluteal pain (63.6%), and coxalgia (18.2%). Two patients complained of both low back pain and gluteal pain. The mean delay between the first visit and an accurate diagnosis of SIF was 23.9 days. This time interval was significantly longer than in patients with other types of pelvic fracture. Four patients underwent MRI targeting the lumbar spine to investigate their symptoms. In all 4 patients, the signal intensity on T1‐weighted and fat‐suppressed images of the second sacral segment was low and high, respectively. Conclusion: This study demonstrates that accurate diagnosis of SIF may be delayed because of difficulties in detecting this type of fracture on plain X‐ray and the non‐specific nature of the presenting complaints. Emergency physicians should keep SIF in mind when investigating patients who complain of low back pain or gluteal pain. Findings at the second sacral segment on MRI targeting the lumbar spine may aid early diagnosis of this type of pelvic fracture.

Intradural lumbar disc herniation after percutaneous endoscopic lumbar discectomy: case report

A 64-year-old man was referred to the authors with low-back pain (LBP) and right leg pain with a history of previously diagnosed lumbar disc herniation (LDH) at L4-5. He had undergone 2 percutaneous endoscopic lumbar discectomies (PELDs) for the herniation at another institution, and according to the surgical record of the second surgery, a dural tear occurred intraoperatively but was not repaired. Postoperative conservative treatments such as an epidural block and blood patch had not relieved his persistent LBP or right leg pain. Upon referral to the authors, MRI and myelography revealed an intradural LDH. The herniated mass was removed by durotomy, and posterior lumbar interbody fusion was performed. His symptoms were partially improved after surgery. Primary suture is technically difficult when a dural tear occurs during PELD. Therefore, close attention should be paid to avoiding such tears, and surgeons should increase their awareness of intradural LDH as a possible postoperative complication of PELD.

Complete Fracture-Dislocation of the Thoracolumbar Spine with No Critical Neurological Deficit: A Case Report

Fractures at the thoracolumbar junction are the most common spinal column fractures. Among type C fractures in the Arbeitsgemeinschaft für Osteosynthesefragen Spine Classification, cases with complete fracture-dislocations of the spinal column often result in a critical neurological deficit despite surgical treatment. We present a case of an 18-year-old man who had a complete fracture-dislocation of the T12 vertebral body and multiple injuries following high-energy trauma but no critical neurological deficits. Because of active bleeding in the left thoracic cavity, the patient underwent open reduction of the T12 vertebral body and anterior spinal fusion of the T11-L1 vertebral bodies via an anterior approach between the T9 and T10 ribs within 24 h of the accident. Four months postoperatively, the patient could ambulate independently, with a slight disturbance of light touch. At 6 months postoperatively, plain computed tomography scans showed bony union of the T12 vertebral body. We postulated two reasons for the absence of critical neurological dysfunction: (1) spontaneous spinal canal sparing because of the fracture of the right superior articular process in the L1 vertebral body and (2) fracture morphology, that is, a rotational fracture with mild to moderately strong shearing stress to the dura mater.

Massive femoral osteolysis secondary to loosening of a cemented roughened long stem: a case report.

The surface finish of a femoral stem plays an important role in the longevity of cemented total hip arthroplasty. In efforts to decrease the rate of aseptic loosening, some prostheses have been designed to have a roughened surface that enhances bonding between the prosthesis and cement, but clinical outcomes remain controversial. We present a rare case of massive osteolysis with extreme femoral expansion that developed after cemented revision total hip arthroplasty. The destructive changes in the femur were attributable to abnormal motion of the stem and were aggravated by the roughened precoated surface of the long femoral component. Revision surgery using a total femur prosthesis was performed because there was insufficient remaining bone to fix the new prosthesis. The surgical technique involved wrapping polypropylene meshes around the prosthesis to create an insertion for the soft tissue, which proved useful for preventing muscular weakness and subsequent dislocation of the hip.

Prevalence of High-Intensity Zones in the Lumbar Spine According to Age and Their Correlation with Other Degenerative Findings on Magnetic Resonance Imaging

Introduction A high-intensity zone (HIZ) in an intervertebral disc of the lumbar spine is a high-intensity signal located in the posterior annulus fibrosus on T2-weighted magnetic resonance imaging (MRI). There is limited information on the prevalence of HIZ in the lumbar spine according to age. The aim of this cross-sectional study was to investigate the prevalence of HIZ in the lumbar spine by age and the correlation between HIZ and other degenerative findings, such as disc degeneration, disc bulging and herniation, and changes in adjacent vertebral endplates on lumbar MRI. Methods We retrospectively reviewed MRI studies of 305 patients (1525 discs) with low back pain, leg pain, or numbness. The prevalence of HIZ was calculated in 5 age groups (<20, 20-39, 40-59, 60-79, 80-91 years). Results The number of patients in the 5 age groups was 19, 38, 69, 145, and 36, respectively. The prevalence of HIZ in the 5 age groups was 11.8%, 47.3%, 52.2%, 42.8%, and 50.0%, respectively. Disc degeneration was observed in 58.1% and 39.2% of discs with and without HIZ, respectively; disc bulging and herniation was observed in 63.9% and 41.1% and intensity changes at adjacent end plates in 11.6% and 10.0%, respectively. Conclusions Prevalence of HIZ from the third decade of life onward was around 50%, with no significant change in prevalence beyond the age of 20 years. HIZ was correlated with disc degeneration, disc bulging, and disc herniation in patients with LBP, leg pain, or numbness.

Prognostic value of dynamic MRI positive enhancement integral color mapping in osteosynthesis of undisplaced femoral neck fractures

AIMS The common treatment for an undisplaced femoral neck fracture is osteosynthesis. Two major complications of osteosynthesis are non-union and late collapse of the femoral head. We speculated that femoral head perfusion is one of the most important factors that affect the outcome of osteosynthesis after femoral neck fracture. We have preoperatively estimated femoral head perfusion by dynamic MRI positive enhancement integral color mapping (PEICM). The purpose of this study was to evaluate the outcomes of undisplaced femoral neck fractures based on PEICM. PATIENTS AND METHODS Sixty-eight patients participated in this prospective study. All patients underwent PEICM in a 1.5-Tesla MRI machine using coronal fast spoiled gradient echo imaging sequences with gadopentetate dimeglumine as the contrast agent. Femoral head perfusion was displayed via color mapping using PEICM. Three types were distinguished. For type A, the color was identical to unaffected side indicated normal perfusion. For type B, the color was darker than unaffected side indicated decreased perfusion. For type C, the color was black indicated complete absence of perfusion. All patients underwent osteosynthesis with three cannulated screws. The rates of non-union and late collapse for each type were calculated. RESULTS Sixteen patients were classified as Type A, 43 as Type B, and 6 as Type C. The non-union rates were 0% for Type A, 6.7% for Type B, and 50.0% for Type C. The late collapse rates were 0% for Type A, 4.4% for Type B, and 0% for Type C. CONCLUSION PEICM precisely detected femoral head perfusion. Primary prosthetic replacement should be considered for older patients with Type C to minimize the chances of revision surgery, even in undisplaced femoral neck fractures.

Compression of the Femoral Vessels by a Pseudotumor after Metal-on-Metal Total Hip Arthroplasty

Here we present a case of pseudotumor following total hip arthroplasty (THA) that resulted in a circulatory disturbance caused by compression of the femoral vasculature. A 63-year-old man presented with pain, swelling, and redness of the left leg 5 years after primary metal-on-metal THA using the AML-Plus stem, Pinnacle® acetabular cup, and 36 mm diameter Ultamet™ metal head system (DePuy Orthopaedics, Warsaw, IN). Enhanced computed tomography and magnetic resonance imaging revealed a large cystic lesion extending from the left hip anteriorly to the intrapelvic region and compressing the left femoral vessels. Percutaneous puncture of the lesion yielded a dark red aspirate and the patient was diagnosed to have a pseudotumor causing compression of the femoral vessels. We performed revision surgery to replace the metal head and metal liner with a smaller ceramic head and polyethylene liner without removal of the stem. Corrosion of the head-neck junction was identified intraoperatively with no obvious wear on the bearing surfaces. The left leg swelling and redness improved immediately postoperatively. A large pseudotumor should be kept in mind as a cause of vascular compression with unilateral leg edema in a patient who has undergone metal-on-metal THA.

Correlation between coxa profunda and morphological parameters of acetabular coverage in a Japanese cohort: A CT study

BACKGROUND Coxa profunda is generally considered an indicator of acetabular overcoverage. However, recent studies have opposed this view. The correlation between coxa profunda and acetabular overcoverage thus remains controversial. The purpose of this study was to investigate the prevalence of coxa profunda and the association between coxa profunda and acetabular coverage based on sex in Japanese subjects using computed tomography. METHODS We reviewed the computed tomography scans of 151 Japanese consecutive patients (302 hips) aged <50 years who underwent abdominopelvic computed tomography for symptoms unrelated to hip disease. Coxa profunda was diagnosed when the floor of the acetabular fossa touched or was medial to the ilioischial line. We measured the lateral center edge angle, acetabular roof obliquity angle, acetabular version, and anterior and posterior acetabular sector angles as parameters of acetabular coverage. RESULTS Coxa profunda was observed in 45.7% of all subjects, and was more common in females (63.0%) than in males (29.5%). We found no significant differences in the incidence of coxa profunda among subjects with dysplasia, overcoverage, and normal coverage. Males with coxa profunda showed significantly greater lateral center edge angle, anterior acetabular sector angle, and lower acetabular roof obliquity angle, whereas anterior and posterior acetabular sector angles were greater in all subjects and females with coxa profunda. Coxa profunda showed poor sensitivity (57.7%) and specificity (56.8%) for detecting overcoverage in all subjects. CONCLUSIONS Coxa profunda is a common radiographic feature in Japanese patients, especially in women. Coxa profunda may be less useful for diagnosing acetabular overcoverage because of its common occurrence with various hip morphologies and its poor specificity for detecting acetabular overcoverage. However, men with coxa profunda have greater acetabular coverage, so coxa profunda may contribute to acetabular coverage in men. We should take into account that coxa profunda may have different implications between the sexes.