Effects of lateral circumflex femoral artery ligation on blood flow to the surrounding muscles in the direct anterior approach.

BACKGROUND: The direct anterior approach to the hip joint enables the identification and ligation of the lateral circumflex femoral artery. However, the effect of lateral circumflex femoral artery ligation on blood flow to the muscles surrounding the hip remains unknown. This study clarified the changes in blood flow to the surrounding muscles following ascending branch ligation of this artery. METHODS: We included 36 consecutive patients (8 male and 28 female) who underwent total hip arthroplasty via the direct anterior approach for hip osteoarthritis between April 2015 and July 2016. The intraoperative blood flow to the tensor fascia latae (TFL), vastus lateralis (VL), rectus femoris (RF), and subcutaneous tissue (control) was measured using a laser Doppler blood flow meter. Measurements were repeated after artery ligation and at the end of surgery. We compared the means (±SD) of these measurements at each location and time point. RESULTS: The patients' mean age was 64.2 ± 9.0 years, systolic and diastolic blood pressures were 92.8 ± 13.6 and 54.9 ± 9.1 mmHg, respectively, and body mass index was 23.1 ± 3.9 kg/m2. Hypertension was noted in 35.9% patients and dyslipidemia in 27.8%. The mean surgical duration was 101 (70-158) min. The preligation blood flow in TFL, VL, RF, and subcutaneous tissue was 3.91 ± 1.93, 5.15 ± 2.19, 4.51 ± 2.24, and 3.03 ± 0.99 mL/min/100 g, respectively. CONCLUSIONS: Blood flow to TFL significantly decreased post ligation and at the end of surgery. However, there was no change in blood flow to VL and RF.

Clinical Outcomes According to Femoral and Acetabular Version After Periacetabular Osteotomy.

BACKGROUND: Patients with acetabular dysplasia often have abnormal femoral and acetabular version. The effect of combined femoral and acetabular version on clinical outcomes after periacetabular osteotomy for the treatment of acetabular dysplasia remains unclear. The purposes of the present study were (1) to evaluate the association of combined femoral and acetabular version with clinical outcome after periacetabular osteotomy and (2) to investigate the association of femoral version independently with clinical outcome after periacetabular osteotomy. METHODS: We retrospectively reviewed the records for 92 consecutive patients (95 hips) who had undergone periacetabular osteotomy for the treatment of symptomatic acetabular dysplasia. The patient cohort comprised 85 females and 7 males with a mean age of 38.9 years at the time of surgery. The mean duration of follow-up was 4.8 years (range, 2.0 to 7.2 years). Femoral and acetabular version and the alpha angle were measured on postoperative computed tomography scans. Clinical outcomes included range of motion and the modified Harris hip score. Analysis of variance was used to investigate the effect of femoral version on clinical outcomes. Analysis of covariance was used to adjust for potential covariates. RESULTS: Combined femoral and acetabular version after periacetabular osteotomy was slightly, but significantly, correlated with postoperative flexion (r = 0.222; p = 0.031) and internal rotation in flexion (r = 0.326; p = 0.001). Patients with mild femoral version (<15°) experienced significantly less postoperative internal rotation in flexion than those with severe femoral version (>35°); however, this difference was lost after adjustment for potential covariates. There were no differences among femoral version groups (mild, moderate, and severe) in terms of improvements in the clinical outcomes of pain, function, and activity. CONCLUSIONS: Combined femoral and acetabular version after periacetabular osteotomy was significantly correlated with postoperative range of motion. Abnormality of femoral version associated with acetabular dysplasia did not demonstrate any effect on the clinical outcomes of periacetabular osteotomy. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Preservation technique of the piriformis tendon is superior to reattachment technique in terms of contiguity and muscle atrophy: using magnetic resonance imaging.

PURPOSE: The preservation technique of the piriformis tendon during the posterolateral approach in total hip arthroplasty (THA) is reportedly superior to the reattachment technique in terms of dislocation. However, the long-term effects of preservation of the piriformis tendon during THA remain unknown. In this study, we evaluated the contiguity of the piriformis/conjoined tendon and atrophy of the piriformis/internal obturator muscle during a long-term postoperative follow-up using magnetic resonance imaging (MRI). METHODS: We retrospectively evaluated 48 patients with available MRI. The 48 patients were classified into a P group ( n = 29), in which the piriformis tendon was preserved, and an R group ( n = 19), in which the piriformis was reattached after sectioning. The mean follow-up duration was 45.9 months. The contiguity of the piriformis/conjoined tendon and atrophy of the piriformis/internal obturator muscle were evaluated in all patients. RESULTS: The piriformis tendon remained attached to the greater trochanter in all P-group patients and 68.4% of R-group patients. The mean piriformis muscle atrophy ratios were 15.9% ± 21.1% in the P group and 41.6% ± 19.1% in the R group ( p < 0.001). The conjoined tendon repair remained intact in 72.4% of P-group patients and 36.8% of R-group patients ( p < 0.05). The mean internal obturator muscle atrophy ratio was 31.4% ± 26.2% in the P group and 50.4% ± 19.1% in the R group ( p < 0.05). No postoperative pulmonary embolism, wound infection, deep infection, or hip dislocation occurred. CONCLUSIONS: In our study, we suggest that the preservation technique of the piriformis tendon is superior to the reattachment technique in terms of contiguity and muscle atrophy.

The prevalence and risk factors for delayed union of the superior pubic ramus at one year after curved periacetabular osteotomy: its risk factor and outcome.

PURPOSE: Curved periacetabular osteotomy (CPO) has been developed for the treatment of acetabular dysplasia. While several studies have reported its good clinical results, the complications of CPO include delayed union and nonunion of the superior pubic ramus. The purpose of this study is to investigate the prevalence of delayed union of the pubis one year after CPO, and to determine the risk factors for this complication. METHODS: The study examined 113 hips that underwent CPO between 2008 and 2012. Delayed union was assessed based on the anteroposterior radiography one year after CPO. A superior pubic ramus union group (U group) and a delayed union group (D group) were retrospectively compared regarding patient characteristics, clinical evaluations, and radiographic parameters. RESULTS: Delayed union rate was 16.8%. The D group contained a significantly greater proportion of smokers (p < 0.001). The gap at the pubic osteotomy site on CT coronal images was significantly larger in the D group (p < 0.001), and the cut-off value for the risk of nonunion was larger than 5.1 mm. Multivariate regression analysis indicated that smoking (OR 10.7, 95% CI 2.1-55.4) and a gap at the superior pubic ramus >5.1 mm (OR 16.5, 95% CI 3.7-73.7) were significantly associated with delayed union as independent risk factors. CONCLUSION: The prevalence of delayed union one year after CPO was 16.8%. Smoking and a gap larger than 5.1 mm at the pubic osteotomy site are risk factors for delayed union after CPO.

Three-dimensional computed tomography analysis on bony birth canal after bilateral periacetabular osteotomy.

BACKGROUND: Curved periacetabular osteotomy (CPO) is one of the joint preserving procedures for developmental dysplasia of the hip. CPO requires osteotomy of the medial wall of the acetabulum, which may cause narrowing of the bony birth canal and this step may result in increased risk of cesarean delivery. We analyzed the narrowest part of the bony birth canal using three-dimensional computed tomography (3D-CT) before and after bilateral CPO. METHODS: Between February 2007 and March 2014, there were 29 cases of bilateral CPO in which both pre- and post-operative 3D-CT were available. Transverse diameters of the pelvic inlet, contraction, outlet, expansion, and teardrop were analyzed. Among them, the narrowest part of the bony birth canal was investigated, which being smaller than the normal lower threshold value for vaginal delivery (95 mm) was considered as a risk for cesarean delivery. RESULTS: The transverse diameters of both pelvic expansion and teardrop significantly decreased after CPO (both p < 0.01), while other diameters showed no significant changes. Among these two diameters, the narrowest diameter of the bony birth canal was the pelvic teardrop in all 29 cases. That in 24 patients (82.8%) was greater than 95 mm, while that in five patients (17.2%) showed less than 95 mm. CONCLUSIONS: Based on 3D-CT analysis, the narrowest part of the bony birth canal after bilateral CPO was the pelvic teardrop. In this study, 82.8% of the patients showed pelvic teardrop diameter greater than 95 mm, while that of the other patients (17.2%) were less than 95 mm.

New cross-table lateral radiography method for measuring acetabular component anteversion in total hip arthroplasty: a prospective study of 93 primary THA.

INTRODUCTION: Various methods have been described for measuring acetabular component anteversion. However, accurate measurement of anteversion is difficult. We herein propose a new method using cross-table lateral (CL) radiography performed with the contralateral hip flexed to 45° (45° flexed CL radiography). The main purpose of this study was to evaluate the reliability and validity of this new method. METHODS: The study group included 93 patients who underwent total hip arthroplasty (THA). All hips were evaluated with computed tomography (CT) and both standard and 45° flexed CL radiographs to measure acetabular component anteversion the week after THA. The intraobserver and interobserver reliability of each measurement was assessed. Plain radiography measurements were compared with reference CT measurements to evaluate their validity. RESULTS: All measurements had excellent intraobserver and interobserver reliability, and plain radiography measurements correlated well with CT measurements. The mean measurements were 21.9° (3°-39°) with CT, 24.9° (7°-47°; p<0.001) with standard CL radiographs, and 22.5° (7°-43°; p = 0.112) with 45° flexed CL radiographs. DISCUSSION: The anteversion values measured with our new method were closer to the CT values used as a reference standard than those with standard CL radiographs. Our new method appears to be reliable and valid for measuring acetabular component anteversion.

Re-dislocation after revision total hip arthroplasty for recurrent dislocation: a multicentre study.

PURPOSE: Although most case of dislocations after total hip arthroplasty (THA) can be managed with conservative treatment, recurrent dislocation may require surgical intervention. This multicentre study was conducted to evaluate the re-dislocation rate after revision THA for recurrent dislocation, and to determine the risk factors for re-dislocation. METHODS: We retrospectively reviewed the 88 hips in 88 patients who underwent revision THA for recurrent dislocation at five institutions between 1995 and 2014. The mean patient age at surgery was 68.5 years and the mean follow-up period was 53.1 months. Multivariate logistic regression was performed to identify risk factors for re-dislocation. RESULTS: Sixteen hips in 16 patients (18.2 %) re-dislocated at a mean of 25.5 months (range, 1-83 months) after revision THA. Multivariate analysis identified osteonecrosis of the femoral head (odds ratio [OR] = 5.62 vs. osteoarthritis) and a femoral head size < 32 mm (OR = 3.86) as independent risk factors for re-dislocation. Eight hips required additional revision THA for re-dislocation. CONCLUSION: The re-dislocation rate after revision THA for recurrent dislocation remains high, suggesting the need for prevention measures. We recommend the use of a femoral head size ≥ 32 mm.

Acetabular labrum blood flow in developmental dysplasia of the hip: an intraoperative in vivo study using laser Doppler flowmetry.

BACKGROUND: The vascular supply to the acetabular labrum is important in the treatment of labral lesions. However, in vivo blood flow measurements in the acetabular labrum have not been described in the literature. The purpose of this study was to examine this blood flow in vivo using laser Doppler flowmetry (LDF) in patients with acetabular dysplasia. METHODS: Periacetabular osteotomy combined with arthroscopy was performed in 47 consecutive patients (three males, 44 females; mean age at surgery, 35.6 years; range, 15-60 years). In all patients, blood flow in the acetabular labrum was measured with LDF during arthroscopy. The acetabular labral lesions were categorized according to the modified Beck classification: detachment and full-thickness labral tears were assigned to the T group and normal labrum to the N group. Blood flow rates in the acetabular labrum were compared between the T and N groups. The associations between labral blood flow and the lateral center-edge angle (CEa) and patient age were also evaluated. RESULTS: The T and N groups comprised 31 and 16 patients, respectively. The mean blood flow rate was 1.94 ± 0.41 ml/min/100 g in the T group and 1.94 ± 0.34 ml/min/100 g in the N group, with no significant difference between the groups (P = 0.884). No association was noted between blood flow and either the CEa or patient age (ß = -0.018, P = 0.077 and ß = -0.001, P = 0.770, respectively). CONCLUSIONS: On LDF, blood flow in the acetabular labrum was present in all patients, regardless of the severity of acetabular labral tears, CEa, or age.

Polyethylene Wear Associated With 26- and 32-mm Heads in Total Hip Arthroplasty: A Multicenter, Prospective Study.

BACKGROUND: Although there were many clinical studies of highly cross-linked polyethylene (XLPE) wear among different femoral head diameters, few referred to thickness of XLPE in case larger femoral heads were used because smaller sockets were frequently used for Asian population. METHODS: This prospective study included 240 hips that underwent primary total hip arthroplasty using XLPE combined with 26-mm (group S) or 32-mm (group L) cobalt-chromium head with maximum follow-up of 10 years. We measured 3-dimensional (3-D) linear penetration rate of XLPE among same implant design groups except head diameter and estimated the validity of thinner XLPE. RESULTS: Our study demonstrated comparable 3-D linear penetration rates, which were 0.06 ± 0.07 mm/y for group S and 0.03 ± 0.02 mm/y for group L at 10 years after surgery and penetration rates seemed to be almost constant with no significant difference after 3 years. Minimum liner thickness (5.3 mm for 48-mm socket in combination with 32-mm femoral head) and the second thinnest XLPE (6.3 mm in case of socket from 50 mm to 54 mm combined with 32-mm femoral head) was distributed in 25% and 72% with group L, respectively, and there were no significant differences in penetration rates between 5.3-mm- and 6.3-mm-thickness groups. CONCLUSION: Our study suggested that whether to select 26- or 32-mm diameters of femoral head does not affect XLPE wear in combination with this type of articulation.

Neurectomy for Bilateral Morton's Neuroma A Case Report of a Male Patient.

Morton's neuroma is a common condition that mainly affects middle-aged women, and many articles have addressed the surgical treatment of this condition. Previous reports have described bilateral neuroma excision in women but not in men. We report a rare case of bilateral neuromas in a male patient treated with simultaneous neurectomy.

Duplication of chromosome segment 12q13-15 in a lipomatous tumor with minimal nuclear atypia: A case report.

Ordinary lipoma is cytogenetically characterized by structural rearrangements, particularly translocations, of 12q13-15. By contrast, atypical lipomatous tumors exhibit supernumerary ring or giant marker chromosomes that are composed mainly of amplified material from the 12q13-15 chromosome segment. The present study describes the cytogenetic and molecular cytogenetic findings from a lipomatous tumor with minimal nuclear atypia that was identified in a 49-year-old female patient. Magnetic resonance imaging of the right shoulder revealed a 13-cm fatty mass in the subcutaneous layer that possessed only pencil-line septa. Contrast-enhanced fat-suppressed T1-weighted images demonstrated faint enhancement. A marginal excision was performed. Histologically, the tumor was composed of lobules that consisted of mature adipocytes separated by thin fibrous septa. There was minimal nuclear atypia in certain cells, and a small number of binucleated cells were also observed within the tumor. Immunohistochemically, the tumor cells did not reveal the expression of murine double-minute 2 (MDM2). Cytogenetic analysis revealed a complex karyotype with several numerical and structural alterations, including 12q rearrangements. Spectral karyotyping demonstrated a duplication of chromosome segment 12q13-15. Interphase fluorescence in situ hybridization analysis revealed no MDM2 gene amplification. The present case indicates that duplication of 12q may be associated with minimal nuclear atypia in a subset of lipomatous tumors.

A Study of Risk Factors for Tracheostomy in Patients With a Cervical Spinal Cord Injury.

STUDY DESIGN: A retrospective, consecutive case series. OBJECTIVE: To determine the risk factors for a tracheostomy in patients with a cervical spinal cord injury. SUMMARY AND BACKGROUND DATE: Respiratory status cannot be stabilized in patients with a cervical spinal cord injury (CSCI) for various reasons, so a number of these patients require long-term respiratory care and a tracheostomy. Various studies have described risk factors for a tracheostomy, but none have indicated a relationship between imaging assessment and the need for a tracheostomy. The current study used imaging assessment and other approaches to assess and examine the risk factors for a tracheostomy in patients with a CSCI. METHODS: Subjects were 199 patients who were treated at the Spinal Injuries Center within 72 hours of a CSCI over 8-year period. Risk factors for a tracheostomy were retrospectively studied. Patients were assessed in terms of 10 items: age, sex, the presence of a vertebral fracture or dislocation, ASIA Impairment Scale, the neurological level of injury (NLI), PaO2, PaCO2, the level of injury on magnetic resonance imaging (MRI), the presence of hematoma-like changes (a hypointense core surrounded by a hyperintense rim in T2-weighted images) on MRI, and the Injury Severity Score.Items were analyzed multivariate logistic regression, and P < 0.05 was considered to indicate a significant difference. RESULTS: Twenty-three of the 199 patients required a tracheostomy, accounting for 11.6% of patients with a CSCI. Univariate analyses of the risk factors for tracheostomy revealed significant differences for six items: age, Injury Severity Score, presence of fracture or dislocation, ASIA Impairment Scale A, NLI C4 or above, and MRI scans revealing hematoma-like changes. Multivariate logistic regression analyses revealed significant differences in terms of two items: NLI C4 or above and MRI scans revealing hematoma-like changes. Thirty patients had both an NLI C4 or above and MRI scans revealing hematoma-like changes. Of these, 17 (56.7%) required a tracheostomy. CONCLUSION: Patients with an NLI C4 or above and MRI scans revealing hematoma-like changes were likely to require a tracheostomy. An early tracheostomy should be considered for patients with both of these characteristics. LEVEL OF EVIDENCE: 3.

Injury to the Obturator Artery During Periacetabular Osteotomy: A Case Report.

CASE: We describe a middle-aged woman who had undergone periacetabular osteotomy (PAO) on both hips successively within a two-year period. Although the first PAO was successfully performed on the right hip without any complications, injury to the obturator artery occurred during the subsequent PAO on the left hip. In this case, the obturator artery seemed to be injured at the medial base of the iliopectineal eminence during osteotomy. CONCLUSION: PAO has been employed as a reconstructive surgery for acetabular dysplasia. However, given the proximity of intrapelvic vascular structures, there is a risk of iatrogenic vascular injury.

Translocation (1;5) in a Glomus Tumor.

Glomus tumor is a rare perivascular neoplasm that usually occurs in the distal extremities of young adults. Recent molecular studies have identified microRNA 143-NOTCH fusions or NOTCH1-3 rearrangements in benign and malignant glomus tumors. Herein, we describe the cytogenetic and molecular cytogenetic findings of a glomus tumor arising in the left wrist of a 45-year-old man. Physical examination showed a 1.3-cm, blue-red, tender nodule. Magnetic resonance imaging demonstrated a subcutaneous, well-circumscribed mass with low signal intensity on T1-weighted sequences and high signal intensity on T2-weighted sequences. Contrast-enhanced fat-suppressed T1-weighted sequences showed a homogeneous, strong enhancement. A marginal excision was performed and histopathological examination confirmed the diagnosis of a glomus tumor. Cytogenetic and spectral karyotypic analyses showed a novel rearrangement involving chromosome bands 1p13 and 5q32. There has been no evidence of local recurrence four months after surgery. To the best of our knowledge, this is the first case of sporadic glomus tumor with t(1;5).

Outcome of peri-acetabular osteotomy for hip dysplasia in teenagers.

PURPOSE: Peri-acetabular osteotomy, especially curved peri-acetabular osteotomy, is an effective surgical procedure for re-orientating the acetabulum. However, there have been few reports on this procedure in teenagers. The purpose of this study was to investigate the treatment outcomes of curved peri-acetabular osteotomy in teenagers. METHODS: We retrospectively reviewed 33 hips in 27 teenage patients with acetabular dysplasia who underwent curved peri-acetabular osteotomy between 1995 and 2012. The mean age was 17.0 years (range, 14-19 years). The mean follow-up duration at the most recent physical examination was 33.3 months (range, 24-96 months). All hips were evaluated in terms of the Harris hip score, radiographic measurements, and complications. RESULTS: The mean Harris hip score improved from 80.1 points pre-operatively to 95.4 points post-operatively (p < 0.001). There were significant differences in all of the radiographic measurements between the pre-operative and post-operative values (p < 0.001). One major complication occurred (symptomatic ischial nonunion) and required subsequent surgery. Nine hips had minor complications, including nonunion of the superior ramus osteotomy (four hips), superficial stitch abscess (two hips), and transient lateral femoral cutaneous nerve palsy (three hips). CONCLUSIONS: Satisfactory results can be obtained clinically and radiographically after curved peri-acetabular osteotomy in adolescents. Osteotomy for acetabular dysplasia is effective in teenagers.

Periosteal chondroma of the distal tibia: Computed tomography and magnetic resonance imaging characteristics and correlation with histological findings.

Periosteal chondroma is a rare benign hyaline cartilage neoplasm situated on the bone surface. This is the presentation of a unique case of periosteal chondroma arising in the left distal tibial metaphysis of a 25-year-old female patient with a history of antecedent trauma. The physical examination revealed swelling and tenderness in the anterolateral aspect of the left distal lower limb. Plain radiographs revealed a discernible soft tissue lesion with peripheral foci of mineralization. Computed tomography scans confirmed the presence of a surface-based mass with peripheral ossification and a thin rim of calcification. On magnetic resonance imaging, the well-circumscribed mass exhibited intermediate signal intensity on T1-weighted sequences and high signal intensity with foci of decreased signal intensity on T2-weighted sequences. Contrast-enhanced T1-weighted sequences revealed predominantly peripheral enhancement without intramedullary involvement. Following an open biopsy, marginal excision with curettage of the underlying bone cortex was performed. Histologically, the tumor consisted of mature hyaline cartilage arranged in distinct lobules. Foci of ossification with mature bone trabeculae forming a thin shell-like structure were identified in the periphery of the tumor. The mindbomb E3 ubiquitin protein ligase 1 labeling index was <1%. Based on these findings, the tumor was diagnosed as periosteal chondroma. There has been no evidence of local recurrence at 4 months following surgery. Despite its rarity, periosteal chondroma must be considered as a possible diagnosis when confronted with a surface-based, mineralized lesion in the metaphysis of long bones.

Successful enucleation of large multinodular/plexiform schwannoma of the foot and ankle.

BACKGROUND: It is often challenging to completely resect multinodular/plexiform schwannomas involving important deep nerves using minimally invasive surgically techniques. CASE DESCRIPTION: A 32-year-old woman presented with a 5-year history of a slowly growing, painful mass in the medial aspect of the right ankle. Magnetic resonance imaging (MRI) demonstrated multiple nodular lesions with iso-signal intensity relative to skeletal muscle on T1-weighted sequences and heterogeneous high signal intensity on T2-weighted sequences. Mild to moderate enhancement was identified after gadolinium administration. All 58 tumors were completely enucleated using an intracapsular technique. Histological examination confirmed the diagnosis of schwannoma consisting mainly of Antoni A areas. The burning sensation was relieved immediately after surgery. The patient had no aggravated neurological deficit and was very satisfied with the outcome of the treatment at final follow-up. DISCUSSION AND EVALUATION: We experienced a very rare case of a large multinodular/plexiform schwannoma arising from the posterior tibial nerve and its larger terminal branch. Our case had the characteristic MRI features of this condition. It is extremely important to differentiate multinodular/plexiform schwannoma from plexiform neurofibroma and malignant peripheral nerve sheath tumor, with complete surgical enucleation being curative. CONCLUSIONS: MRI is a clinically useful modality in the evaluation and detection of deep-seated multinodular/plexiform schwannoma. Intracapsular enucleation seems to be an acceptable treatment for this peculiar tumor located in the foot and ankle.

FDG PET/CT and MR imaging of CD34-negative soft-tissue solitary fibrous tumor with NAB2-STAT6 fusion gene.

Extrapleural solitary fibrous tumor (SFT) is an uncommon mesenchymal neoplasm of intermediate biological potential. Herein, we describe the radiological, histological, immunohistochemical and molecular genetic features of an SFT arising in the left thigh of a 55-year-old woman. Magnetic resonance imaging exhibited a well-defined mass with intermediate signal intensity on T1-weighted sequences and heterogeneous high signal intensity on T2-weighted sequences. Contrast-enhanced T1-weighted sequences showed strong homogeneous enhancement of the mass. A prominent vascular pedicle was visible. Integrated positron-emission tomography (PET)/computed tomographic (CT) scan demonstrated a moderate 18F-fluorodeoxyglucose (FDG) uptake (maximum standardized uptake value, 4.45) in the mass. Following an open biopsy, wide excision of the tumor was performed. Histologically, the tumor was composed of a proliferation of spindle cells in a fibrous stroma with focal hyalinization. Thin-walled branching hemangiopericytoma-like vessels were observed. Immunohistochemically, the tumor cells were diffusely positive for signal transducer and activator of transcription 6 (STAT6) but negative for CD34. The MIB-1 labeling index was less than 5%. Subsequent reverse transcriptase-polymerase chain reaction analysis identified a nerve growth factor inducible-A binding protein 2-STAT6 gene fusion. Our case supports the utility of STAT6 immunohistochemistry as an adjunct in the diagnosis of soft-tissue SFT with loss of CD34 positivity. To the best of our knowledge, this is the first report showing the FDG PET/CT findings of soft-tissue SFT.

The relationship between the lesion-to-ankle articular length ratio and clinical outcomes after bone marrow stimulation for small osteochondral lesions of the talus.

PURPOSE: The purpose of this study was to determine the relationship between the defect-to-ankle articular length ratio and clinical outcomes after arthroscopic bone marrow stimulation. METHODS: Seventeen male and 24 female patients (mean age 36.0 years, height 160.7 cm, weight 62.5 kg, body mass index 24.0) with an osteochondral lesion of the talus were treated with arthroscopic bone marrow stimulation and assessed using the Japanese Society for Surgery of the Foot (JSSF) ankle-hindfoot scale, Berndt and Harty scales and clinical outcome criteria. The lengths of the tibial and talar articular surfaces were defined from the anterior tip to posterior tip of the articular cartilage on sagittal magnetic resonance imaging scans. The size of the defect area was defined and determined for each patient on magnetic resonance images using coronal length, sagittal length, and area. The relationship between clinical outcome and sagittal tibia ratio (sagittal length of defect/length of tibia articular cartilage) and sagittal talus ratio (sagittal length of defect/length of talus articular cartilage) were assessed. RESULTS: The mean lesion length was 11 mm (range 6-14 mm), lesion size was 67 mm(2) (range 19-134 mm(2)), sagittal tibia ratio was 0.42 (range 0.21-0.75), and sagittal talus ratio was 0.32 (range 0.16-0.58). The mean JSSF scale improved from 74 (range 18-90) to 89 (range 67-100) postoperatively. Lesion area was not associated with the JSSF scale (r = -0.10, P = 0.52). Talus articular length (r = 0.64, P < 0.0001) and tibia articular length (r = 0.64, P < 0.0001) were correlated with patient height. The sagittal talus ratio and sagittal tibia ratio were not associated with the JSSF scale (r = -0.10, P = 0.55; r = -0.02, P = 0.90). CONCLUSION: Arthroscopic bone marrow stimulation provides good clinical outcomes in small osteochondral lesions of the talus (<15 mm). For small lesions, the lesion size is not a prognostic factor. LEVEL OF EVIDENCE: IV: Retrospective Case Series.

Immunohistochemical, cytogenetic, and molecular cytogenetic characterization of both components of a dedifferentiated liposarcoma: implications for histogenesis.

Dedifferentiated liposarcoma (DDLS) is a malignant adipocytic tumor showing transition from an atypical lipomatous tumor (ALT)/well-differentiated liposarcoma (WDLS) to a non-lipogenic sarcoma of variable histological grades. We present the immunohistochemical, cytogenetic, and molecular cytogenetic findings of DDLS arising in the right chest wall of a 76-year-old man. Magnetic resonance imaging exhibited a large mass composed of two components with heterogeneous signal intensities, suggesting the coexistence of a fatty area and another soft tissue component. The grossly heterogeneous mass was histologically composed of an ALT/WDLS component transitioning abruptly into a dedifferentiated component. Immunohistochemistry was positive for murine double-minute 2 (MDM2), cyclin-dependent kinase 4 (CDK4), and p16 in both components, although a more strong and diffuse staining was found in the dedifferentiated area. The MIB-1 labeling index was extremely higher in the dedifferentiated area compared to the ALT/WDLS area. Cytogenetic analysis of the ALT/WDLS component revealed the following karyotype: 46,X,-Y,+r. Notably, cytogenetic analysis of the dedifferentiated component revealed a similar but more complex karyotype. Spectral karyotyping demonstrated that the ring chromosome was entirely composed of material from chromosome 12. Interphase fluorescence in situ hybridization analysis revealed amplification of MDM2 and CDK4 in both components. These findings suggest that multiple abnormal clones derived from a single precursor cell would be present in DDLS, with one or more containing supernumerary rings or giant marker chromosomes.