Synovial sarcoma of the dorsal aspect of the hand: a case report.

BACKGROUND: Synovial sarcoma is a rare soft tissue sarcoma, with incidences of 0.81/1,000,000 in children and 1.42/1,000,000 in adults. It is most commonly found in soft tissue and rarely in bone. It often has a slow growth pattern and a benign radiologic appearance. CASE PRESENTATION: This study reports a case of metacarpal synovial sarcoma occurring in the hand-wrist of a 32-year-old Iranian man presented with the chief complaint of a lump on the dorsal ulnar side of his left hand and wrist. Initially, the first physician suspected the case to be a ganglion cyst. After two months of conservative treatment, the size of the lesion gradually increased. Magnetic resonance imaging (MRI) was performed and after an excisional biopsy and a postoperative histological analysis, the tumor was identified as a synovial sarcoma. The patient underwent a scheduled surgical procedure. Unfortunately, he had poor follow-ups and brought the pathologic results two months later when, the tumor had incredible growth, which makes this presentation rare. CONCLUSIONS: Since early diagnosis can lead to higher survival rates, this report increases doctors' awareness of this extremely malignant tumor that is rarely seen.

Pediatric parosteal osteosarcoma of the distal radius causing extensive erosive mass effect of the adjacent ulna: a case report.

INTRODUCTION: Parosteal osteosarcomas are low-grade bony malignancies that are treated primarily with surgical resection and reconstruction. This report discusses a unique case of a pediatric patient who presented with a parosteal osteosarcoma of the distal radius causing extensive erosive mass effect and growth disturbance of the adjacent ulna. Likely due to their slow-growing nonaggressive nature, parosteal osteosarcomas have not been previously described to abut adjacent bony structures through direct contact. The patient presented in a significantly delayed manner due to social circumstances, inadvertently revealing this novel behavior. This report reviews this rare case and describes the current understanding of this tumor. CASE PRESENTATION: The patient is a 13-year-old male who presented with a parosteal osteosarcoma of his distal radius. He presented with a palpable wrist mass and wrist stiffness. He presented in a delayed manner with advanced local disease due to social factors. Imaging revealed an osseous radial mass that abutted the ulna and likely stunted its growth. The patient ultimately underwent complex resection and allograft reconstruction of both his distal radius and ulna. Intraoperative pathology was confirmed to have negative tumor margins. Allograft reconstruction of the radius and ulna was performed utilizing patient-specific custom cutting guides. At the 6-month postoperative visit, the patient had no recurrence of the mass, minimal pain, and had almost regained range of motion of the extremities. Clinical radiographs at the 6-month postoperative visit demonstrated allograft incorporation. CONCLUSIONS: A previously unreported case of pediatric parosteal osteosarcoma of the distal radius with erosion of the adjacent ulna through direct contact is presented. The challenges in and the importance of arriving at a definitive diagnosis in a timely manner for the proper treatment of this malignancy are emphasized.

Bioactive Bone Substitute in a Rabbit Ulna Model: Preclinical Study.

BACKGROUND: Current therapies to effectively treat long-bone defects and extensive bone tissue loss remains limited. In this study, we created a new bone substitute by integrating advanced technologies such as structure patterning, controlled release of a bone growth factor and conjugation system for clinically effective bone regeneration. This novel bioactive bone substitute was evaluated for its safety and efficacy using a rabbit ulna model. METHODS: A three dimensional bone patterned cylindrical structure with 1.5 cm in length and 5 mm in diameter was printed using poly(L-lactic acid)(PLLA) as a weight-bearing support and space-filling scaffold. And a bone morphogenetic protein 2 (BMP2) was employed to enhance bone regeneration, and coated to a 3D PLLA using alginate catechol and collagen to prolong the release kinetics. This novel bone substitute (BS)was evaluated for its physico-chemical and biological properties in vitro, and histological analysis and radiographical analysis such as X-ray, CT and micro-CT image analysis were performed to evaluate new bone formation in vivo. RESULTS: The BS possesses an ideal shape and mechanically suitable proeperties for clinical use, with an easy-to-grab and break-resistant design at both ends, 80 ± 10 MPa of compression strength, and BMP2 release for two months. Histological analysis demonstrated the biocompability of BS with minimal inflammation and immune response, and X-ray, CT and micro-CT demonstrated effective new bone formation in rabbit ulna defect model. CONCLUSION: The preclinical study of a novel bioactive bone substitute has shown its safe and effective properties in an animal model suggesting its clinical potential.

Retained cartilaginous core in the distal radius of a small breed dog.

A 5-month-old castrated male Smooth Fox Terrier presented for a 1-month history of right thoracic limb lameness. Physical examination revealed right elbow pain on extension and mild soft tissue swelling of the distal antebrachium. Radiographs and computed tomography showed elongated focal radiolucent regions in the distal radial metaphysis. There was incongruity of the right elbow with a short radius. Bone biopsy and histopathology of the regions confirmed a retained cartilaginous core characterised by bony trabeculae with frequently retained central cartilaginous cores. A dynamic proximal ulnar ostectomy was performed to improve elbow congruity. The owner was instructed to restrict activity to short leash walks for 8 weeks followed by a gradual activity increase. On follow-up examination 16 weeks after operatively, the lameness and elbow pain were resolved. Radiographs at that time showed a healed ulnar ostectomy, proper elbow congruity, and resolved retained cartilaginous core.

A Case of Acute Plastic Deformation of the Forearm in a Medieval Hispano-Mudejar Skeleton (13-14th Centuries AD).

INTRODUCTION: Acute plastic deformation refers to a traumatic bending or bowing without a detectable cortical defect. CASE PRESENTATION AND DISCUSSION: We describe a rare case from an individual that was exhumed from the Hispano-Mudejar necropolis in Uceda (Guadalajara, Spain) dated between the 13th and 14th centuries AD. The case corresponds to an adult woman, with a bowing involvement of the left ulna and radius. After making the differential diagnosis with various pathologies likely to present with this alteration, we reached the diagnosis of acute plastic deformation of the forearm through external and radiological examination and comparison with the healthy contralateral forearm. CONCLUSIONS: Acute plastic deformation is a rare traumatic injury, not described until the last century and only rarely described in palaeopathological contexts. We contribute a new case, the first being sufficiently documented, contributing to the knowledge and diagnosis of this type of trauma in the ancient bone, while deepening the knowledge of the living conditions of the medieval Mudejar population of Uceda.

The effect of ulnar variance on the pisotriquetral joint.

BACKGROUND: Pisotriquetral joint (PTJ) disorders are an important cause of ulnar-sided wrist pain but are often underrecognized. Ulnar variance (UV) has been associated with several wrist pathologies. PURPOSE: To determine the effect of UV on PTJ in patients with trauma. MATERIAL AND METHODS: A total of 143 patients (77 men, 66 women; mean age=41.64 ± 18.07 years) were included. Patients with fractures, severe and high-energy trauma, arthritic conditions, avascular necrosis, congenital deformity, bone and soft-tissue tumors, suboptimal image quality, and incorrect joint position were excluded. UV and the amount of PTJ subluxation were evaluated using coronal and sagittal computed tomography images. RESULTS: PTJ subluxation was divided into five grades. A statistically significant difference was found between the presence of PTJ subluxation and sex (P = 0.045). PTJ subluxation was more common in men (46.8%) than in women (30.3%). There was no significant difference between the presence of PTJ subluxation and age (P = 0.758). The patients were also divided into three groups as positive, neutral, and negative UV. A statistically significant relationship was found between the UV and presence of PTJ subluxation (P = 0.01). PTJ subluxation was significantly less in the neutral (none=51.1%, present=48.9%; P < 0.05) and negative (none=77.8%, present=22.2%; P < 0.05) groups. CONCLUSION: PTJ subluxation was found to be less among the groups with neutral and negative UV in our study population. PTJ subluxation is more common in men while there is no relationship with age. UV and gender may be risk factors for PTJ subluxation by affecting force dynamics at the wrist joint.

[Treatment of Giant Cell Tumor of Bone in the Distal Radius and Ulna]. / Lécba obrovskobunecného kostního nádoru distálního radia a ulny.

PURPOSE OF THE STUDY The preferred treatment of giant cell tumor of bone is curettage with the use of local adjuvant. If the tumor spreads beyond the bone into soft tissues, en bloc excision should be performed. Intralesional curettage allows joint preservation, but it is associated with a high recurrence rate. The purpose of the study was to identify the risk factors for local recurrence and to compare the functional outcomes after both types of surgical procedures. MATERIAL AND METHODS The group included 16 patients (5 women, 11 men) with giant cell tumor of bone in distal forearm treated at the First Department of Orthopedic Surgery, St. Anne s University Hospital Brno in 2005-2019. The mean age of patients was 38 years (22-53). The follow-up period was 6.75 years (2-15) on average. The most common location of the tumor was distal radius (14). In 6 patients denosumab treatment was indicated. Based on the obtained data, we compared the effects of gender, Campanacci grade, type of surgery and administration of denosumab on the risk of local recurrence. The functional outcomes were evaluated retrospectively based on the Musculoskeletal Tumor Society scoring system for upper limb salvage surgeries. RESULTS Resection and reconstruction using an osteocartilaginous allograft was performed in 9 patients. Seven patients were treated with tumor curettage with bone cement used to fill the cavity. The group of patients who underwent curettage showed a significantly higher mean MSTS score 89% compared to the group of patients with resection with the mean MSTS score 66% (P < 0.05). Local tumor recurrence was reported in 3 patients (18.75%). No statistically significant difference was found in gender, tumor grade, radicality of surgery or administration of targeted therapy with respect to the incidence of local recurrence. Altogether 6 complications (37.5%) were observed in the group. DISCUSSION The treatment of a giant cell tumor of bone aims to completely remove the tumor and to preserve the best possible function of the limb. The complications in distal forearm involve particularly an increase incidence of local recurrence and painful or limited range of motion of the wrist. Whereas curettage with the use of local adjuvant is burdened with a higher recurrence rate, resection with allograft reconstruction of bone defect is usually associated with poorer functional outcomes. CONCLUSIONS Tumor curettage using local adjuvant is preferred in a well-circumscribed tumor and offers an excellent functional outcome. En bloc tumor resection and reconstruction using an osteocartilaginous allograft is a suitable treatment option for a locally advanced tumor with a low risk of local recurrence. Key words: giant cell tumor of bone, distal radius, distal ulna, curettage, osteocartilaginous allograft.

Evaluation of prestyloid recess morphology and ulnar-sided contrast leakage in CT arthrography of the wrist.

BACKGROUND: In wrist arthrograms, aberrant contrast material is frequently seen extending into the soft tissue adjacent to the ulnar styloid process. Since the prestyloid recess can mimic contrast leakage in CT arthrography, this study aims to provide a detailed analysis of its morphologic variability, while investigating whether actual ulnar-sided leakage is associated with injuries of the triangular fibrocartilage complex (TFCC). METHODS: Eighty-six patients with positive wrist trauma history underwent multi-compartment CT arthrography (40 women, median age 44.5 years). Studies were reviewed by two board-certified radiologists, who documented the morphology of the prestyloid recess regarding size, opening type, shape and position, as well as the presence or absence of ulnar-sided contrast leakage. Correlations between leakage and the presence of TFCC injuries were assessed using the mean square contingency coefficient (rɸ). RESULTS: The most common configuration of the prestyloid recess included a narrow opening (73.26%; width 2.26 ± 1.43 mm), saccular shape (66.28%), and palmar position compared to the styloid process (55.81%). Its mean length and anterior-posterior diameter were 6.89 ± 2.36 and 5.05 ± 1.97 mm, respectively. Ulnar-sided contrast leakage was reported in 29 patients (33.72%) with a mean extent of 12.30 ± 5.31 mm. Leakage occurred more often in patients with ulnar-sided TFCC injuries (rɸ = 0.480; p < 0.001), whereas no association was found for lesions of the central articular disc (rɸ = 0.172; p = 0.111). CONCLUSIONS: Since ulnar-sided contrast leakage is more common in patients with peripheral TFCC injuries, distinction between an atypical configuration of the prestyloid recess and actual leakage is important in CT arthrography of the wrist.

Nonlethal presentations of CYP26B1-related skeletal anomalies and multiple synostoses syndrome.

Retinoic acid exposures as well as defects in the retinoic acid-degrading enzyme CYP26B1 have teratogenic effects on both limb and craniofacial skeleton. An initial report of four individuals described a syndrome of fetal and infantile lethality with craniosynostosis and skeletal anomalies caused by homozygous pathogenic missense variants in CYP26B1. In contrast, a 22-year-old female was reported with a homozygous missense pathogenic variant in CYP26B1 with complex multisuture craniosynostosis and intellectual disability, suggesting that in some cases, biallelic pathogenic variants of CYP26B1 may be compatible with life. Here we describe four additional living individuals from two families with compound heterozygous pathogenic missense variants in CYP26B1. Structural assessment of these additional missense variants places them further from the catalytic site and supports a model consistent with milder nonlethal disease. In addition to previously reported findings of multisuture craniosynostosis, conductive hearing loss, joint contractures, long slender fingers, camptodactly, broad fingertips, and developmental delay/intellectual disability, skeletal imaging in our cases also revealed gracile long bones, gracile ribs, radioulnar synostosis, and carpal and/or tarsal fusions. These individuals broaden the phenotypic range of biallelic pathogenic variants in CYPB26B1 and most significantly clarify that mortality can range from perinatal lethality to survival into adulthood.

TBX3 and TBX5 duplication: A family with an atypical overlapping Holt-Oram/ulnar-mammary syndrome phenotype.

Holt-Oram syndrome (HOS) is a rare, autosomal dominant heart-hand syndrome caused by mutations in the TBX5 gene. A wide spectrum of TBX5 mutations have been reported previously, most resulting in a null allele leading to haploinsufficiency. TBX5 gene duplications have been previously reported in association with typical and atypical HOS phenotypes. Ulnar-Mammary syndrome (UMS) is a distinct rare, autosomal dominant condition caused by mutations in the TBX3 gene. TBX5 and TBX3 are physically linked in cis on human chromosome 12 and contiguous chromosome 12q24 deletions comprising both TBX5 and TBX3 genes have been previously reported but to our knowledge, duplications have never been described. We report on a large German family with at least 17 affected individuals over 6 generations bearing a duplication at 12q24.21 identified on array-CGH comprising both TBX5 and TBX3 genes. Affected patients are presenting with HOS and UMS symptoms, consisting of variable limb anomalies involving the radial and the ulnar rays and cardiac findings such as congenital heart defects, persistent arterial duct or aortic stenosis, and non-classical symptoms, such as supernumerary nipples and cardiomyopathy. Fluorescence in situ hybridisation confirmed a tandem duplication at the 12q24.21 locus. This is the first report of a contiguous TBX3/TBX5 duplication associated with HOS/UMS phenotype.

Melanotic Neuroectodermal Tumor of Infancy in the Ulna of an Infant: A Very Rare Tumor: A Case Report.

CASE: A 4-month-old boy presented with a nontender swelling of the right proximal forearm of 2 months' duration. Radiological evaluation showed lytic lesion surrounded by sclerotic bone in the ulna with soft-tissue extension. Histopathological examination showed tumor of round and epithelioid cells containing melanin, interpreted as melanotic neuroectodermal tumor. The patient underwent a wide excision of the shaft of the ulna with creation of radioulnar synostosis. There is no recurrence 6 years after surgery. CONCLUSION: Melanotic neuroectodermal tumor is rare in the appendicular skeleton and has to be differentiated from other round cell tumors and osteomyelitis. As far as we know, this is the first reported case in the ulna.

Computed Tomographic Measurement of Trochlear Depth in Three Breeds of Brachycephalic Dog.

OBJECTIVE: The aim of this study was to determine the trochlear sulcus depth of three common brachycephalic breeds at risk of medial patellar luxation. STUDY DESIGN: Retrospective blinded clinical study using a previously validated ratio (T/P) of maximal trochlear sulcus depth (T) and maximal patellar craniocaudal thickness (P) measured on computed tomography, to assess trochlear sulcus depth in Pugs, French Bulldogs and English Bulldogs without clinical patellar luxation. The effect of breed on T/P was assessed using one-way linear regression models. RESULTS: The mean T/P was affected by breed (p < 0.001). There was significant difference between Pugs (0.45) and French Bulldogs (0.38) and between Pugs and English Bulldogs (0.4). There was no significant difference between Pugs and previously published data for non-brachycephalic and mixed breed dogs (0.46) (p = 0.39). Mean T/P was significantly reduced in the brachycephalic dog breeds combined compared with the previously published data (p < 0.001). CONCLUSION: The trochlear sulcus varies by breed and was more shallow in French and English Bulldogs than Pugs, hence a shallow sulcus may be a breed-driven characteristic. The three breeds assessed are at risk of patellar luxation but sulcus depth did not directly correlate with previously published risk factors-the contribution of sulcus depth to the aetiopathogenesis of patellar luxation remains unclear. Trochlear recession to achieve patellar coverage of 50% may be excessive considering maximal breed normal depth.

The reconstruction after en-bloc resection of giant cell tumors at the distal radius: A systematic review and meta-analysis of the ulnar transposition reconstruction technique.

BACKGROUND: En-bloc resection of giant cell tumors (GCTs) of the distal radius remains the mainstay treatment for those with high-graded lesions. Several techniques have been described for reconstruction of the resected segment, of which transposition of the ipsilateral ulna is scarcely reported. OBJECTIVES: To investigate the efficacy and safety of the different techniques of ulnar translocation following GCTs total resection. METHODS: A systematic review and meta-analysis was conducted concerning the reported functional outcomes, including grip strength, range of forearm motion, functional scores, and new bone formation, as well as postoperative complications, such as delayed union, local recurrence and metastasis. The ranges of functional outcomes were reviewed and the pooled prevalence rates of complication and their respective 95% confidence intervals (95% CIs) were computed. RESULTS: In a total of 12 studies, 90 patients (51.1% males, 84.8% had Campanacci grade III tumors) underwent five different reconstruction techniques. As compared to the normal side, the mean grip strength in the affected side ranged between 59 and 71%. The average union time was 1-8 months, while delayed union was reported in 50% (95% CI, 15.35 to 84.65) of patients whom their grafts were fixed with Steinmann pins. The shortest union time, the highest forearm supination and pronation degrees, new bone formation at the ulnar stump, and the highest functional scores were reported following a modified distal radius plate technique. Using a dynamic compression plate and a clover leaf plate provided lower, but considerable, functional outcomes. CONCLUSION: Ulnar translocation following GCT en-bloc resection warrants additional investigation in large cohorts and well-designed studies to corroborate the promising outcomes presented in this review.

Inevitable nonunion after ulnar shortening osteotomy in patients with ulnar impaction syndrome and breast cancer under bisphosphonate treatment.

BACKGROUND: Nonunion after ulnar shortening osteotomy (USO) was observed at a high rate in patients undergoing long-term bisphosphonate (BP) maintenance treatment after breast cancer surgery. Here, we report the unique features of these nonunions. METHODS: In total, 485 patients who had undergone USO between March 2008 and September 2017 were screened for inclusion based on the following criteria: (1) definitive nonunion after USO; (2) prior history of or ongoing BP therapy after the diagnosis of breast cancer; and (3) no evidence of metastasis in the ulna treated with USO, as determined based on the radiological evaluation. RESULTS: Five patients with histories of breast cancer and subsequent BP treatment were identified; all (100%) of these patients showed definitive nonunion after USO. The mean age was 56.2 years, and all ulnae were on the contralateral side to that of the original breast cancer. Intravenous Ibandronate® and Zolendronate® were administrated to one and four patients, respectively. The mean period of administration was 67.8 months. Three patients exhibited suspicious lesions impending atypical fracture on their femurs, and the other two patients were treated by intramedullary nailing after the occurrence of atypical fractures. Radiological evaluation revealed no evidence of a metastatic lesion, including in the musculoskeletal system, in any patient. Osteosynthesis was performed with cancellous iliac bone graft and mean of 4.3 months after osteosynthesis, union in all cases was achieved. CONCLUSIONS: Problems associated with BP treatment are well known. Even in cases in which the agent is essential for preventing bony metastasis of breast cancer, the normal bony physiology, including bone turnover and healing, is likely to be compromised. In addition to atypical fractures of the femur and ulna, procedures such as USO are likely to be affected by BP. Furthermore, not only a primary iliac bone graft but also other method (oblique osteotomy) should be needed to avoid nonunion during plating in USO. LEVEL OF EVIDENCE: IV, Retrospective case series.

Simultaneous dislocation of the radial head and distal radio-ulnar joint without fracture in an adult patient: a case report and review of literature.

BACKGROUND: Simultaneous dislocation of the radial head and distal radio-ulnar joint without fracture (Criss-Cross Injury) in an adult patient is rarely reported in previous studies. The pathological changes and injury patterns have not been clearly demonstrated. CASE PRESENTATION: A 26-year-old woman presented with acute pain of the right wrist and elbow after a fall from cycling. Physical examination revealed an unstable elbow and wrist joint. Plain radiographs showed volar dislocation of the radial head and dorsal dislocation of the distal radius without associated fracture, forming a criss-cross appearance of the ulna and radius on the lateral radiograph. MRI images confirmed partial rupture of the proximal interosseous membrane from its dorsal attachment on the radius, as well as partial rupture of the medial collateral ligament. Conservative treatment failed because the radiocapitellar joint and distal radio-ulnar joint could not be simultaneously reduced. Surgical exploration revealed a highly unstable radial head, but the annular ligament was found to be intact. Manual force was applied to reduce the radial head and a percutaneous K-wire was used to stabilize the proximal radioulnar joint with the forearm in full supination. After surgery, the elbow was immobilized in 90° flexion by a long arm cast for 4 weeks. The K-wire was removed at 6 weeks postoperatively. At 18 months postoperatively, the patient had regained a full range of flexion and extension, with normal supination and a slight limitation in pronation. CONCLUSIONS: The proximal IOM, especially the dorsal band, was injured in Criss-Cross injuries, while the central part of the IOM remained intact. This injury pattern distinguished itself from Essex-Lopresti injury, which mainly involves rupture of the central band of the IOM.

Effect of Distal Ulna Osteochondroma Excision and Distal Ulnar Tether Release on Forearm Deformity in Preadolescent Patients With Multiple Hereditary Exostosis.

BACKGROUND: Multiple hereditary exostosis is a benign condition that can lead to significant forearm deformity secondary to physeal disturbances. As the child grows, the deformity can worsen as relative shortening of the ulna causes tethering, which may lead to increased radial articular angle, carpal slippage, and radial bowing, over time this tethering can also result in radial head subluxation or frank dislocation. Worsening of forearm deformities often require corrective reconstructive osteotomies to improve anatomic alignment and function. The purpose of this study is to evaluate the effectiveness of osteochondroma excision and distal ulnar tether release on clinical function, radiographic anatomic forearm alignment, and need for future corrective osteotomies. METHODS: The authors reviewed a retrospective cohort of preadolescent patients who underwent distal ulna osteochondroma resection and ulnar tethering release (triangular fibrocartilage complex). Patients were invited back and prospectively evaluated for postoperative range of motion, pain scores, self-reported and parent-reported Disabilities of the Arm, Shoulder, and Hand (DASH) and Pediatric Outcomes Data Collection Instrument (PODCI) scores. In addition, preoperative and final postsurgical follow-up forearm x-rays were reviewed. RESULTS: A total of 6 patients and 7 forearms were included in our study with an average age of 7.9 years at time of surgery. The average final follow-up was 7.4 years. With respect to range of motion, only passive radial deviation demonstrated improvement -20 to 14 degrees (P=0.01). Although there was not statistically significant change in radial articular angle, this study did find an improvement in carpal slip 75.7% to 53.8% (P=0.03). At final follow-up DASH score was 5.71 (σ=5.35), PODCI Global Function score was 95.2 (σ=5.81), and PODCI-Happiness score 98 (σ=2.74). Visual analogue scale appearance and visual analogue scale pain assessment were 1.67 (σ=1.21) and 1.00 (σ=1.26), respectively, at final follow-up. No patient in the cohort developed a radial head dislocation. Only one of 7 forearms required a corrective osteotomy within the study's follow-up time period. CONCLUSIONS: Surgical excision of forearm osteochondromas with ulnar tether release in the preadolescent patients improves carpal slip, may help to prevent subsequent surgical reconstruction and provides satisfactory clinical results at an average 7-year follow-up. LEVEL OF EVIDENCE: Level III-therapeutic study.

Computed tomographic morphometry of the biceps brachii muscle tendon of dogs affected by the medial coronoid disease.

The objective of this study was to measure the biceps brachii muscle (BBM) attachment to the medial coronoid process (MCP) using computed tomography images and to compare these data between clinically healthy and dogs affected by medial coronoid disease (MCD). Computed tomography was performed in MCD-affected and healthy dogs. Multiplanar reconstruction views were obtained to measure distance (cm) of the BBM attachment point to the MCP. Results showed that the mean BBM attachment point-to-MCP was 1.42 ± 0.23 cm in MCD-affected and 1.27 ± 0.20 cm in healthy dogs, respectively. In dogs with MCD, the BBM attachment point-to-MCP was significantly more abaxial than in clinically healthy dogs (p < .001). The results of this study support the hypothesis that the BBM attachment site is more abaxial to the MCP and therefore may contribute to supraphysiological overload leading to MCD. Albeit more research is necessary, this study proves a relationship between the BBM attachment point and the development of MCD.

Bilateral congenital radioulnar synostosis in an Early Horizon subadult burial from the site of Atalla, Peru.

OBJECTIVE: This study was undertaken to identify pathological conditions within the population living at Atalla (1000-500 BCE), an important early village site and ritual center located in Huancavelica, Peru. MATERIALS: Articulated burials (N = 3) and commingled human remains excavated during the 2015 and 2016 field seasons. METHODS: Osteological remains were analyzed for macroscopic evidence of pathological changes. RESULTS: A case of bilateral proximal radioulnar fusion was observed in an Early Horizon (ca. 800 BCE) subadult skeleton (Individual 1). A differential diagnosis of this pathology supports congenital radioulnar synostosis (CRUS), a rare developmental condition. Enamel hypoplasia was also identified in the same individual. CONCLUSIONS: Burial treatment of Individual 1 does not provide any indication that CRUS was afforded an exceptional social significance. CONTRIBUTION TO PALEOPATHOLOGY: This example of CRUS is notable as it represents the second published archaeological case of CRUS from Peru and the earliest reported case globally. LIMITATIONS OF THIS STUDY: The osteological sample currently available from this site is limited. SUGGESTIONS FOR FUTURE RESEARCH: Increased fieldwork in this region is recommended to further clarify the distribution and social significance of CRUS in the prehistoric Andes.

Unusual form of the distal bone defect of ulna with neurofibromatosis type 1: A case report.

RATIONALE: Bone malformation occurs in 10% to 25% neurofibromatosis type 1 (NF-1) patients, and the manifestations are scoliosis, congenital arch and pseudo-joint formation, bone cyst, and pathologic fracture. However, a large segmental defect without obvious signs of bone destruction has rarely been reported. PATIENT CONCERNS: A 4.5-year-old male presented with a 4-year history of shortening of the right upper limb and radial head dislocation. The X-ray indicated a lack of the distal part of the right ulna and radial head dislocation. DIAGNOSIS: The X-ray showed obvious bone resorption at the right ulna distal, proximal stubble, and distal part of the epiphyseal residue, which was 4.3 mm shorter after 14 months. The patient was finally diagnosed with NF-1 according to the pathologic examination. INTERVENTIONS: The treatment included tumor resection, ulnar osteotomy, and fixation by an Ilizarov frame. OUTCOMES: The Ilizarov frame was removed after 2.7 months of surgery. The radial head was successfully repositioned, and the elbow joint function was significantly improved. No recurrence of the deformity was noted until now. LESSONS: Osteolysis (defect without bone destruction) is an extremely rare symptom in patients with NF1. Therefore, it is essential to make the right diagnosis by comprehensive and careful physical examination.