1456 Back-To-Back Surgeries: A Clinic Case Report Regarding Multiple Complex Spinal Surgeries for Treatment of Multiple Osteochondroma With Histological Conversion to Chondrosarcoma

Background Multiple Hereditary Osteochondromas [MHO], previously known as multiple hereditary exostoses, is a rare disorder of bone growth, whereby osseous transformation of the cartilage caps within the diaphyses of long bones or flat bones within the skeleton occurs. A significant complication of MHO is the conversion of any present osteochondroma into a malignant chondrosarcoma. Chondrosarcomas are mesenchymal, non-meningothelial tumours and most commonly present with insidious pain, associated neurological deficit by means of impingement of underlying nerves. Case presentation We present a clinical case of a 29-year-old female medical student with a background history of multiple hereditary osteochondromas. A previously competitive cross-fitter, she developed the conversion of MHO into a malignant chondrosarcoma. Presenting to outpatient clinic in late 2017, this lady had a 2-year history of lower back pain and an associated palpable lump. An MRI of the thoracolumbar spine demonstrated a large mass arising from the posterior elements of T11 to L2. A biopsy at the time was found to be of benign pathology, most likely in keeping with this patient’s diagnosis of MHO. The patient returned for review in early 2018, where a repeat MRI showed extension of the previously described lesion into the spinal canal at the level of L1 vertebra. This was concerning that this previously identified osteochondroma lesion could be undergoing malignant transformation. The patient went on to have a series of complex spinal surgeries which we will discuss below.

Lengthening of the ulna by callotasis in children with multiple hereditary exostoses: comparison of methods with and without internal fixation

Purpose The goal of this retrospective study was to compare the gradual lengthening of the ulna in children with multiple hereditary exostoses with and without an elastic intramedullary nail. Methods Between 1998 to 2018, the ulna was lengthened in 28 forearms in 21 patients (aged 7.1 to 16.6 years) using a monolateral external fixator when relative ulnar shortening exceeded 15 mm. In total, 16 forearms were lengthened with the external fixator (group I) and 12 forearms with the addition of an intramedullary elastic nail (group II). Subjective assessment of function, range of movement (ROM) of the wrist and elbow and complications were compared. Ulnar shortening, radial head dislocation, radial articular angle (RAA) and percentage of carpal slip and radial bowing were followed radiographically. The difference between the groups has been evaluated statistically. Results The function of the extremity improved partially in 81% of patients in group I and in 83% of patients in group II. ROM was not improved except for radial deviation. Radial head position did not change. The values in group II in comparison with group I are higher for gain of length and lower for bone lengthening index and for bone healing index. Carpal slip decreased insignificantly. The RAA and radial bowing decreased, the comparison of values between groups and age under and over ten years were not statistically significant. Complications were more common in group I. No permanent complications were noted. Conclusion The addition of an intramedullary nail during the gradual ulnar lengthening improves the gain, bone healing index and rate of complications. Level of Evidence III.

Reconstruction of the Hip in Multiple Hereditary Exostoses

The hip joint involvement in multiple hereditary exostoses (MHE) occurs in 30–90%, causing pain and limitation of motion by femoroacetabular impingement, coxa valga, acetabular dysplasia, hip joint subluxation, and osteoarthritis. The purpose of this study was to investigate the clinical and radiographic outcomes of ten hips in seven patients treated by surgical dislocation and corrective osteotomies between 2004 and 2009. Surgical dislocation and excision of the osteochondromas and varus intertrochanteric osteotomies were performed in all cases when the neck–shaft angle was > 150°. Common sites of osteochondromas were medial, posterior, and anterior neck of the femur. Neck–shaft angle of the femur was improved from a mean of 157° to 139°, postoperatively. On an average, the center-edge angle improved from 20° to 30° postoperatively. We believe that Ganz’s safe surgical dislocation technique is the preferred treatment of MHE. This safeguards the circulation of the femoral head and the osteochondromas can be resected under direct vision. It can be combined with additional corrective osteotomies because the hip affected by MHE is frequently associated with dysplastic changes which can result in premature osteoarthritis.

Femoral Neck Width Predict Low Bone Mass in Patients with Multiple Hereditary Exostoses

Background: Recent report revealed multiple hereditary exostoses (MHE) patients showed the osteoporosis. This study aimed to determine if proximal femur deformities can indicate low bone mass in MHE patients and to investigate the correlation between Z-score or T-score and hip geometry parameters. Patients and Methods: Twenty MHE patients from unrelated families were included in this study. Bone mineral density (BMD) of both femoral neck (n = 40) was examined using dual-energy x-ray absorptiometry. We examined femoral neck axis length (FNAL), femoral head diameter (FHD), femoral neck width (FNW), femoral shaft width (FSW), and femoral neck angle (FNA) and calculated the femoral head-neck ratio (FHNR=FHD/FNW). We examined the correlation between these parameters and Z-score or T-score using linear regression analysis followed by Spearman rank correlation coefficient.Results: Of the patients, 91.7% (22 of 24) male and 100% (16 of 16) female had a Z-score <0 in the femoral neck area. Results also showed that the femoral neck area of 62.5% (15 of 24) male and 56.3% (9 of 16) female patients are within the range for osteopenia. The femoral neck are of seven patients (17.5%) were found to be within the range for osteoporosis. These results suggest that MHE patients tend to have low bone mass. We found a significant correlation between FNW and Z-score (r = -0.3924, P = 0.0123), but there was no significant difference between Z-score and FNAL, FHD, FSW, NSA, and FHNR. We also found that there were significant differences between T-score and FNW and T-score and FHNR (r = -0.4787, P = 0.0018 and r = 0.3636, P = 0.0211, respectively). There was no significant difference between T-score and the other parameters.Conclusions: We found that the femoral neck width significantly correlates with Z-score or T-score. These results suggest that the femoral neck width may be a reliable predicting factor of bone mineral density.

Characteristics of hip impingement syndrome in patients with multiple hereditary exostoses

Backgrounds This study aimed to investigate the characteristic deformities of the hip in multiple hereditary exostoses patients (MHE) and its association with the hip impingement syndrome. Materials and methods Between 2001 and 2019, total 51 patients (102 hips) were evaluated in this study. Patients with MHE were classified to femoro-acetabular impingement (FAI) symptom group, ischio-femoral impingement (IFI) symptom group and non-impingement symptom group by comparing the symptoms, clinical signs and imaging studies. To assess the morphometry of the hip in patients with MHE, the femoral neck-shaft angle, Sharp’s acetabular angle and center-edge (CE) angle were evaluated. Alpha angle was further evaluated to investigate the FAI using radiographs, and the minimum ischio-femoral distance was further measured to investigate the IFI using computed-tomographic (CT) study. Results On hip impingement symptom analysis, FAI symptom and IFI symptom were confirmed in 14 hip joints and 18 hip joints, respectively. Unlike general population, the number of the hip with IFI-symptom was higher than those with FAI symptom in this study. In morphometric evaluation of MHE hips, coxa valga was most prominent deformity with occasional tendency of mild acetabular dysplasia. In a comparison of morphometric study between the impingement symptom group and non-symptom group, the FAI symptom showed significant differences of morphometric measure values than those of the non-symptom group (FAI symptom group vs. Non-FAI symptom group; Femoral neck-shaft angle (153.9 vs 142.6), Sharp’s angle (45.0 vs 41.5), CE angle (21.1 vs 28.8) and alpha angle (76.7 vs 57.9)). Similarly, the IFI symptom group also showed significant differences of morphometric measure values than those of the non-symptom group (IFI-symptom vs. Non-IFI symptom; Femoral neck-shaft angle (150.9 vs 142.7), Sharp’s angle (44.7 vs 41.4), CE angle (21.1 vs 29.3) and alpha angle (73.3 vs 56.8)). In addition, the minimum ischio-femoral distance measured using CT was significantly decreased in the IFI symptom group (IFI symptom group: 6.6, Non-IFI symptom group: 16.4). Conclusion The results suggest that the characteristic deformities represented by coxa valga in the MHE hip act as an offset for FAI symptoms, on the contrary, act as a trigger for IFI symptoms. Level of evidence Level III.