Proximal femur fractures are usually categorized as either a cervical or trochanteric fracture, but the relationship between fracture type and fall direction is not clear. By cadaveric mechanical testing and finite element analysis (FEA), the aims of this research were to verify the factors that define the proximal femur fracture type and to clarify the change in stress distribution based on fall direction.From fresh frozen cadavers, we obtained 26 proximal femora including ten pairs 20 femora. We conducted quasi-static compression tests were conducted in two fall patterns (lateral and posterolateral), and identified the fracture type. We then examined the relationship between fracture type and the following explanatory variables: age, sex, neck shaft angle, femoral neck length, bone mineral density (cervical and trochanteric), and fall direction. In addition, for the ten pairs of femurs, the effect of fall direction on fracture type was examined by comparing the left and right sides. In addition, we generated the proximal femur finite element (FE) models from computed tomography data to simulate and verify the change of stress distribution in different fall direction.In mechanical tests, only fall direction was found to have a significant relationship with fracture type (p = 0.0227). The posterolateral fall group had a significantly higher incidence of trochanteric fractures than lateral fall group (p = 0.0325). According to FEA, it was found that the equivalent stress distribution in the posterolateral fall was found to be more concentrated in the trochanteric area compared to the lateral fall.In proximal femur fractures, fall direction was significantly associated with fracture type; in particular, trochanteric fractures were more likely to occur following a posterolateral fall than a lateral fall.
Proximal femur fractures are usually categorized as either a cervical or trochanteric fracture, but the relationship between fracture type and fall direction is not clear. By cadaveric mechanical testing and finite element analysis (FEA), the aims of this research were to verify the factors that define the proximal femur fracture type and to clarify the change in stress distribution based on fall direction. From fresh frozen cadavers, we obtained 26 proximal femora including ten pairs of 20 femora. We conducted quasi-static compression tests in two fall patterns (lateral and posterolateral), and identified the fracture type. We then examined the relationship between fracture type and the following explanatory variables: age, sex, neck shaft angle, femoral neck length, bone mineral density (cervical and trochanteric), and fall direction. In addition, for the ten pairs of femurs, the effect of fall direction on fracture type was examined by comparing the left and right sides. In addition, we generated the proximal femur finite element (FE) models from computed tomography data to simulate and verify the change of external force in different fall directions. In mechanical tests, only fall direction was found to have a significant relationship with fracture type (p = 0.0227). The posterolateral fall group had a significantly higher incidence of trochanteric fractures than lateral fall group (p = 0.0325). According to FEA, the equivalent stress in the lateral fall was found to be more concentrated in the cervical area than in the posterolateral fall. In proximal femur fractures, fall direction was significantly associated with fracture type; in particular, trochanteric fractures were more likely to occur following a posterolateral fall than a lateral fall.
Soft-tissue tension is an important factor for preventing dislocations after total hip arthroplasty. The purpose of this study was to evaluate the effects of anterior capsule repair for preventing dislocation during primary total hip arthroplasty using the anterolateral approach in the supine position (ALS). This study retrospectively compared the clinical and radiographic outcomes between patients who underwent total hip arthroplasty via the ALS with or without anterior capsule repair at our institute. The cup (radiographic inclination and radiographic anteversion) and stem alignment, operative time, clinical score, and complication were evaluated. Among the 393 hips evaluated, 193 and 200 belonged to the resection and repair groups, respectively. There were significant differences in the inclination and anteversion of the cup and flexion insertion of the stem (42.3° vs. 40.3°, 15.8° vs. 19.8°, and 27.5% vs. 34.0%, respectively). No significant differences in operative time and postoperative Japanese Orthopedic Association hip score were noted. Early dislocation was more common in the resection group compared to the repair group (2 hips vs. 0 hip, respectively), albeit not significantly (1.03% vs. 0%, p = 0.241). Our results demonstrated that the clinical benefit of the anterior capsule repair for preventing dislocation was limited in ALS.
Pelvic ring fractures are defined as life-threatening injuries that can be treated surgically with external or internal fixation. The authors report on an 81-year-old woman with an unstable pelvic fracture accompanying multiple traumas that was successfully treated with a less invasive procedure. The patient was injured in a traffic accident and sustained a total of 20 fractures, including pelvic ring, bilateral rib, and lumbar transverse processes fractures, and multiple fractures of both upper and lower extremities. The pelvic ring fracture was unstable with fractures of the bilateral sacrum with right sacroiliac disruption, right superior and inferior pubic rami, left superior pubic ramus, and ischium. During emergency surgery, bilateral external fixation was applied to the iliac crest to stabilize the pelvic ring. Second and third surgeries were performed 11 and 18 days after the first emergency surgery, respectively, to treat the multiple fractures. At the third surgery, the pelvic ring fracture was stabilized surgically using a less invasive posterior fixation technique. In this technique, 2 iliac screws were inserted on each side following an 8-cm midline posterior incision from the S-1 to S-3 spinous process, with the subcutaneous tissue detached from the fascia of the paraspinal muscles. The S-2 spinous process was removed and 2 rods were connected to bilateral iliac screws to stabilize the bilateral ilium in a switchback fashion. A crosslink device was applied to connect the 2 rods at the base of the S-2 spinous process. Following pelvic fixation, percutaneous pedicle screws were inserted into L-4 and L-5 vertebral bodies on both sides, and connected to the cranial rod connecting the bilateral iliac screws, thus completing the lumbopelvic fixation. The postoperative course was favorable with no postoperative complications. At the 10-month follow-up, bone union had been achieved at the superior ramus of the pubis, the patient did not complain of pain, and her activities of daily life returned to preinjury status. Unstable pelvic ring fractures need to be sufficiently stabilized for good surgical outcome. However, to avoid postoperative complications, a less invasive treatment is preferred, particularly in cases with poor general condition. This procedure is less invasive and provides sufficient stabilization to the unstable pelvic ring fracture, and thus is the ideal surgical procedure for such cases.
Morel–Lavallee lesion (MLL) is a post-trauma degloving cyst, usually filled with blood, lymph, or necrotic tissue, which mostly develops in the area around greater trochanter. MLL is associated with the potential risk of infection and progressive expansion of untreated lesions can cause pressure necrosis of overlying skin.1, 2 However, MLL may be missed because it is not visible on the body surface, and the signs of MLL may not be initially apparent. We report a case of delayed diagnosis of MLL after multiple injuries. A 37-year-old man was run over by a truck. Pelvic fractures were detected, and transcatheter arterial embolization and fixation were performed. On the 10th day, delayed sigmoid colon perforation was diagnosed, and emergency surgery was performed. Postoperative hemoglobin level was 10.6 g/dL, but anemia gradually progressed. On day 28, the hemoglobin level was 6.9 g/dL and a blood transfusion was required. In addition, subcutaneous hematoma remained in the left buttock and thigh, and skin necrosis was found on the left buttock and thigh. Therefore, on day 30, plain CT was performed. Plain CT showed an extensive low-density area in the subcutaneous soft tissues of the low lumbar and the left buttocks extending caudally to the left lower thigh and the right greater trochanter (asterisks) (Figure 1A), a finding consistent with a MLL. Needle aspiration was performed, and 1020 mL of old blood was collected from the lesion. However, contrast-enhanced CT on day 47 showed an encapsulated, subcutaneous lesion in the same area (asterisks) (Figure 1B). MRI on day 51 showed an encapsulated, abnormal-intensity lesion in the subcutaneous soft tissues of the low lumbar and the left buttocks extending caudally to the left lower thigh and the right greater trochanter (asterisks). Within this lesion, T1-weighted images appeared isointense to hypointense, and T2-weighted images appeared predominantly hyperintense. MRI coronal STIR shows no fat suppression (Figure 1C). MRI also showed a partial injury to the muscles of the left buttocks (white arrow). In some places within these muscles, T2-weighted images and STIR appeared hyperintense, and T1-weighted images not appeared hyperintense (Figure 1C). Treatment was based on clinical symptoms, lesion size, severity, age, and co-morbidities.1, 2 In this case, surgical excision was performed on day 55 because of the size of the fluid retention. We opened the lesion widely and debrided the interior, and three drainage tubes were inserted. Negative pressure wound therapy was performed thereafter. The wound was healed at 3 months after the trauma. MLL became more marginated as they aged and the chronic lesions were encapsulated. The majority shape of MLL was lenticular and oval, and there was a trend toward an increase in the size of lesion from the acute to the subacute stage and a decrease in size from the subacute to the chronic stage.3 In this case, CT and MRI were performed after 47 and 51 days showed an encapsulation, but the size of lesion did not decrease. Further, there were not only the separation of the skin and subcutaneous fat from the underlying fascial planes, but also a partial injury to the muscles of the left buttocks. High-energy trauma resulted in more extensive lesions. MRI is available for diagnosis of MLL, but CT is underrecognized.3 Often, MLL is overlooked in patients presenting with multiple injuries.4 Increased awareness of MLL characteristics on CT will lead to early diagnosis and treatment of MLL, and prevent the development of complications. None declared. Approval of the research protocol: N/A. Informed Consent: The patient gave his consent for clinical information relating to this case to be reported in this medical publication. Registry and the Registration No. of the study/Trial: N/A. Animal Studies: N/A. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.
