Operative outcomes and fracture patterns in dysmorphic sacrums.

INTRODUCTION: Sacral dysmorphism has been previously reported to occur in 30 % to 40 % of adult patients. It has been described by 6 widely accepted parameters on outlet x-ray views of the pelvis: steep alar slope, retained S1-S2 disk, presence of mamillary bodies, sacralized L5, tongue in groove SI joint, and non-round neural foramina. Studies have focused on the importance of identifying dysmorphism for safe treatment of fractures in pelvises with dysmorphic upper sacral segments. Less is known regarding whether dysmorphism may be protective against trauma. To our knowledge no studies have focused on how dysmorphic sacrums fracture compared to non-dysmorphic (ND) sacrums, and whether operative rates are different. AIMS: To assess the rate of operative fixation of sacral fractures between pelvises with dysmorphic and ND sacrums, as well as whether a difference exists in fracture morphology between groups. DESIGN/METHODS: This is a retrospective cohort study out of a single level 1 trauma center. Study participants consisted of those sustaining a pelvic ring injury who were 18 years or older in which orthopaedics was consulted, had CT imaging available, and did not have isolated acetabulum fractures. 355 subjects were included of 671 reviewed pelvic ring injuries. Sacrums were deemed dysmorphic if they met at least one of the six dysmorphic features, and it was determined whether they underwent operative intervention. Fracture classifications and patterning were identified on CT imaging. P values were set <0.05. RESULTS: We found that 44 % of inclusions had a dysmorphic sacrum with the most common feature to be a steep alar slope (68 %). 17.17 % of subjects with a ND sacrum underwent treatment versus 16.56 % for dysmorphic sacrums. No statistical difference regarding operative fixation rates was uncovered (p = .879). However, we found a difference in fracture patterns regarding ipsilateral posterior SI joint widening (p = 0.020). CONCLUSION: Our study suggests that sacral dysmorphism is not protective against operative fixation based on no difference in operative rates between groups. However, our data supports that pelvises with dysmorphic sacrums may fracture differently based on the difference observed regarding other pelvic ring injuries.

An Unusual Inverted Talar Neck Fracture-Dislocation.

Talar neck fractures occur on a continuum of injury severity. Hawkins classification, later modified by Canale, is the gold standard method of describing talar neck fractures by the degree of dislocation. It has proven to be clinically relevant in predicting risk of osteonecrosis. Despite its merits, talar neck fractures present on a wide spectrum of involvement of the body and neck, dislocation, and concomitant injuries, making every situation a challenge in treatment. We present a unique case of a talar neck fracture in which the talar dome had dislocated and inverted 180°, which is not described in the widely used Hawkins classification. We recommend urgent open reduction, low threshold for use of a transcalcaneal traction pin and dual incisions, and guarded prognosis of osteonecrosis and posttraumatic arthritis.

Use of the Hybrid Operating Room for Pelvic and Acetabular Fracture Surgery.

The hybrid operating room (HOR) utilizes advanced imaging technology to improve intra-operative visualization and facilitate efficient care in procedures that are relatively image dependent. The robotic C-arm provides improved 2D image quality and is capable of large volume three-dimensional fluoroscopy (3DF) that can rapidly create multiplanar CT like images. Here we discuss on the technique, utility, potential benefits, pitfalls, and complications of using the hybrid suite with and without intra-arterial balloon occlusion for pelvic and acetabular fracture surgery. We also present a case series of patient who underwent pelvic fixation using the HOR. While not advocated for routine use in all pelvic and acetabular fractures; the hybrid suite can be an effective tool in the treatment of complex cases and may facilitate efficient care of the hemodynamically unstable patient. It should be considered when resuscitative stabilization, angioembolization, intra-arterial balloon occlusion, or life-threatening bleeding is anticipated. Additionally, use of the hybrid room allows access to 3D fluoroscopy, and the associated benefits, if a mobile 3D unit is otherwise unavailable. These benefits must be weighed against the cumbersome table, the potential pitfalls with patient size and positioning, and the increased cost to the hospital.

Pseudotumor Caused by a Retained Intra-articular Bullet: A Case Report.

CASE: A 54-year-old man presented with systemic lead poisoning due to a gunshot wound to the hip suffered 35 years prior to presentation. He urgently underwent removal of the bullet with total hip arthroplasty and was found to have a pseudotumor. This case highlights the team-based approach to manage systemic lead poisoning caused by an intra-articular bullet. CONCLUSION: We report on the first documented case of systemic lead toxicity and a pseudotumor caused by an intra-articular bullet. An expeditious, team-based approach is necessary for appropriate treatment. Our treatment algorithm can guide future teams on the management of this reversible disorder.

Are piriformis reconstruction implants ideal for prophylactic femoral neck fixation?

OBJECTIVES: Prophylactic femoral neck fixation may be performed in the setting of geriatric diaphyseal femur fracture, pathologic or impending atypical femur fractures. Fixation constructs often utilize cephalomedullary implants with one or two proximal interlocking screws into the femoral head/neck. Variations in proximal femoral anatomy and implant design can interfere with the placement of two screws in the femoral head and neck. Our objective was to assess the strength of piriformis entry reconstruction implants with one versus two proximal interlock screws for prophylactic femoral neck fixation. METHODS: Thirty fourth generation synthetic femur models were separated into 5 groups. The control group was an intact femur, and the second group was an intact femur with an entry hole in the piriformis fossa. The remaining groups had an intramedullary nail placed with either 0, 1, or 2 screws placed into the femoral head and neck. Each femur was mechanically loaded along the mechanical axis through the femoral head. Load to failure and failure displacement were recorded. RESULTS: Mean load to failure was 5583 ± 543 N in the intact femur. Constructs with 2 screws had a significantly higher mean load to failure (3223 ± 474 N) compared to one screw constructs (2368 ± 280 N). All of the experimental groups remained significantly lower than the intact femur model (p < 0.05). CONCLUSION: Our results demonstrate that piriformis entry reconstruction implants have a significantly lower load to failure compared to an intact femur irrespective of screw construct. Further studies are needed to investigate this potential iatrogenic weakening.

Bone Morphogenetic Protein-2 Promotes Human Mesenchymal Stem Cell Survival and Resultant Bone Formation When Entrapped in Photocrosslinked Alginate Hydrogels.

There is a substantial need to prolong cell persistence and enhance functionality in situ to enhance cell-based tissue repair. Bone morphogenetic protein-2 (BMP-2) is often used at high concentrations for osteogenic differentiation of mesenchymal stem cells (MSCs) but can induce apoptosis. Biomaterials facilitate the delivery of lower doses of BMP-2, reducing side effects and localizing materials at target sites. Photocrosslinked alginate hydrogels (PAHs) can deliver osteogenic materials to irregular-sized bone defects, providing improved control over material degradation compared to ionically cross-linked hydrogels. It is hypothesized that the delivery of MSCs and BMP-2 from a PAH increases cell persistence by reducing apoptosis, while promoting osteogenic differentiation and enhancing bone formation compared to MSCs in PAHs without BMP-2. BMP-2 significantly decreases apoptosis and enhances survival of photoencapsulated MSCs, while simultaneously promoting osteogenic differentiation in vitro. Bioluminescence imaging reveals increased MSC survival when implanted in BMP-2 PAHs. Bone defects treated with MSCs in BMP-2 PAHs demonstrate 100% union as early as 8 weeks and significantly higher bone volumes at 12 weeks, while defects with MSC-entrapped PAHs alone do not fully bridge. This study demonstrates that transplantation of MSCs with BMP-2 in PAHs achieves robust bone healing, providing a promising platform for bone repair.

Binding to COMP Reduces the BMP2 Dose for Spinal Fusion in a Rat Model.

STUDY DESIGN: The aim of this study is to test the effect of cartilage oligomeric matrix protein (COMP) on enhancing rhBMP-2 induced spinal fusion in a prospective 8-week interventional trial of spinal fusion in rats. OBJECTIVE: To determine whether the amount of bone morphogenetic protein-2 (BMP-2) required to achieve spinal fusion in a pre-clinical model can be reduced by the addition of COMP. SUMMARY OF BACKGROUND DATA: BMPs are applied clinically at supraphysiological doses to promote spinal fusion by inducing osseous growth, but dose-related limitations include ectopic bone formation and local inflammatory reactions. COMP is a matricellular BMP-binding protein expressed during endochondral ossification and fracture healing. In vitro studies demonstrate enhanced activity of BMP bound to COMP. We hypothesized that BMP bound to COMP could achieve equivalent spinal fusion rates at lower doses and with fewer complications. METHODS: Posterolateral intertransverse process spinal fusion at L4 to L5 was performed in 36 Lewis rats. COMP (10 µg) was tested with or without "low-dose" rhBMP-2 (2 µg), and the results were compared with the "low-dose" (2 µg rhBMP-2) and "high-dose" (10 µg rhBMP-2) groups. All groups utilized insoluble collagen bone matrix carrier (ICBM). Fusion was evaluated by radiology, histology, and manual palpation. BMP release kinetics were evaluated in vitro. RESULTS: Fusion grading of microCT images demonstrated that the fusion rate with the COMP+LoBMP was statistically equivalent to HiBMP, and significantly better than LoBMP without COMP. These results were confirmed with radiographs and manual palpation. BMP release kinetics suggest that COMP increased local concentrations of BMP due to decreased growth factor retention on the scaffold. CONCLUSION: COMP enhances BMP-induced bone formation, enabling lower doses of BMP to achieve the same level of spinal fusion. COMP may function by affecting the availability and biological presentation of BMP-2. A decrease of BMP-2 required for fusion may reduce dose-related adverse effects, surgical costs, and improve clinical outcomes. LEVEL OF EVIDENCE: N/A.

Femoroacetabular impingement: current concepts in diagnosis and treatment.

EDUCATIONAL OBJECTIVES: As a result of reading this article, physicians should be able to: 1. Identify the etiology of femoroacetabular impingement. 2. Assess femoroacetabular impingement on physical examination. 3. Recognize femoroacetabular impingement on imaging studies. 4. Discuss modern techniques to effectively treat femoroacetabular impingement, both open and arthroscopic. Femoroacetabular impingement (FAI) is a recently proposed concept describing abnormal anatomic relationships within the hip joint that may lead to articular damage. Impingement is caused by bony deformities or spatial malorientation of the femoral head-neck junction and/or the acetabulum. These abnormalities lead to pathologic contact and shearing forces at the acetabular labrum and cartilage during physiological hip motion. There is an increasing body of evidence that these forces lead to cartilage wear and eventual osteoarthritis. Treatment options for FAI are evolving rapidly. Although the gold standard remains open hip dislocation, arthroscopic techniques have shown significant promise. It is possible that early recognition and treatment of subtle deformity about the hip may reduce the rate of hip osteoarthritis in the future.

Periprosthetic supracondylar femur fracture treated with spanning external fixation.

Periprosthetic supracondylar fractures of the femur after total knee arthroplasty represent a devastating complication for the patient and a technical challenge for the surgeon. Treatment is often complicated by advanced patient age, retained cement, and accompanying osteoporosis. We present the case of a 54-year-old woman with a comminuted fracture of the distal femur just above a total knee prosthesis. She had a complex past medical history, including extensive coronary artery disease, morbid obesity, chronic osteoporosis, anemia, diabetes, and rheumatoid arthritis. She was a Jehovah's Witness and thus refused all blood products. Given her medical history, religious preferences, and fracture comminution, a spanning external fixator was used. She completed fracture union with an excellent clinical and radiographic result at 2 years.