Anatomy and Deficiency of the Deltoid Muscle: A Review of Literature.

BACKGROUND/OBJECTIVE: The deltoid muscle is impacted by common injuries and clinical procedures. This study aims to summarize the anatomy, injuries, and clinical considerations involving the deltoid muscle. METHOD: A literature search was performed using PubMed and Google Scholar using keywords that focused on the deltoid muscle in the shoulder. Primary research articles and appropriate summary articles were selected for review. RESULTS: Reduced deltoid muscle function can be caused by axillary nerve injury, rupture of the deltoid itself, or iatrogenic damage to the muscle. The deltoid muscle has an intimate relationship with the axillary nerve and neighboring rotator cuff muscles. Injury to these nearby structures may be masked by compensating deltoid strength. Examination maneuvers in clinic such as the Akimbo Test should be used to isolate the deltoid muscle to determine if the presenting weakness is from the deltoid itself or from other surrounding injury. Additionally, prior to performing clinical procedures, it is important to be cognitive of the injuries that can occur. For example, incisions that extend distally from the acromion should not extend beyond 5-7 cm as this is the common location of the axillary nerve and vaccine administration should take measures to avoid misplaced injections to avoid unnecessary trauma. CONCLUSION: Deficiency of the deltoid muscle can be debilitating to patients and it is best clinical practice be aware of the anatomy, various causes, tests, and avoidance measures to help diagnose, restore or preserve normal functioning.

Compartment Syndrome of the Gluteal Region: A Rare Condition Requiring a High Index of Suspicion.

Introduction: Compartment syndrome, an exceptionally rare condition, is a surgical emergency that can quickly escalate to limb ischemia and necrosis without treatment. Most cases occur post-trauma, typically affecting the anterior compartment of the leg. Patients present with pain out of proportion to their physical examination findings and often have an early hallmark discovery of pain with passive extension. Compartment syndrome of the buttock requires an even higher index of suspicion, as the condition is even more uncommon, and the diagnosis is complicated by it being difficult to palpate the affected area and passively extend the leg when the patient is supine. Case Report: This case report presents an 83-year-old female with compartment syndrome of the left gluteal region, status post-fall 1 day earlier. She was admitted to the medical team for observation and failed to respond to narcotic pain medication. The physical examination revealed firm, tense, left gluteal compartments with buttock hematoma and surrounding muscle induration, significant pain, and extremity weakness in the sciatic nerve distribution. An emergent fasciotomy was performed to decompress the affected compartments. Conclusion: All physicians must be mindful of gluteal compartment syndrome in patients complaining of buttock pain, especially after pelvic trauma, who present with buttock swelling, tense gluteal compartments, and severe gluteal pain. A delay in diagnosis or treatment can lead to severe consequences, including disability, irreversible gluteal muscle damage, sciatic nerve dysfunction, kidney failure, or death.

Isolated Upper Extremity Compartment Syndrome: A Case of Rhabdomyolysis-induced Myoglobinuria and Acute Kidney Injury after Opioid Overdose.

Introduction: The association between rhabdomyolysis secondary to traumatic crush injuries and the resultant acute kidney injury has been well described . The pathway of opioid overdose and acute kidney injury (AKI) has been documented but not fully elucidated. This process is believed to be multifactorial in its pathophysiology, but it remains obscure. Acidosis, systemic hypoxia, hypothermia, muscle compression, immunologic, or direct toxic effects have been identified as contributing factors to opioid-induced AKI. Musculoskeletal crush injuries account for one of the most common causes of rhabdomyolysis leading to AKI. However, the vast majority of crush injuries documented involve large regions of the body and most commonly involve the lower extremity. This is hypothesized to be due to the need for a considerable amount of muscle necrosis and sufficient myoglobinuria to cause AKI. There is a paucity of literature describing isolated upper extremity crush injuries severe enough to cause AKI. The case described herein outlines a patient who developed isolated right upper extremity compartment syndrome and resultant rhabdomyolysis leading to AKI in the setting of an opioid overdose. Case Report: Rhabdomyolysis may be caused by a variety of metabolic events. The pathophysiology of rhabdomyolysis secondary to acute crush injuries with resultant AKI is well documented. However, the literature describing cases of acute kidney injury caused by upper extremity compartment syndrome-induced rhabdomyolysis is limited. We present the case of a 33-year-old male who developed right upper extremity compartment syndrome after being incapacitated following an opioid overdose. He subsequently underwent emergent fasciotomies and was found to have an AKI secondary to rhabdomyolysis in the acute post-operative period. Conclusion: This case describes a patient who was found to have isolated right upper extremity compartment syndrome and subsequent rhabdomyolysis, which resulted in AKI following an opioid overdose. This case highlights that an isolated incidence of upper extremity rhabdomyolysis is sufficient to cause acute kidney injury. The literature describing this pathology in isolated upper extremity injuries is limited as this phenomenon is typically encountered in the setting of lower extremity compartment syndrome.The pathophysiology and mechanism of this pathology are of particular importance to the fields of orthopedic surgery, nephrology, and internal medicine. This case highlights the need for early and adequate fluid resuscitation in patients with isolated upper extremity injuries to minimize the risk of subsequent AKI.

Peripheral Arterial Disease and Prosthetic Joint Infection Resulting in Hip Disarticulation: A Case Report.

Introduction: The aim of this study was to report a patient with refractory prosthetic joint infection (PJI) and severe peripheral arterial disease that necessitated hip disarticulation (HD), a rare and aggressive procedure. While this is not the first HD performed due to PJI, this is the first reported incidence that deals with profound infection burden along with immense vascular disease that has failed all other treatment options. Case Report: We report a case of an elderly patient with a prior history of the left total hip arthroplasty, PJI, and severe peripheral arterial disease who underwent a rare HD procedure and was discharged with minimal complications. Before this major surgery, several surgical revisions and antibiotic regimens were attempted. The patient had also failed a revascularization procedure to treat an occlusion stemming from the peripheral arterial disease and had developed a necrotic wound at the surgical site. Irrigation and debridement of associated necrotic tissue was unsuccessful and due to concerns such as cellulitis, HD was performed with patient consent. Conclusion: HD is a rare procedure that comprises only 1-3% of all lower limb amputations and is reserved for extremely deleterious indications such as infection, ischemia, and trauma. Complication and 5 year mortality rates have been reported to be as high as 60% and 55%, respectively. Despite these rates, the patient case illustrates a situation, in which early detection of indications for HD prevented further negative outcomes. Based on this case, we believe that HD is a reasonable treatment of choice in patients with severe peripheral arterial disease who fail revascularization and prior moderate treatment options. However, the limited availability of data involving HD and variety of comorbid conditions necessitate further analysis in terms of outcomes.

Injections for treatment of carpal tunnel syndrome: A narrative review of the literature.

Background: Carpal tunnel syndrome is an extremely common condition in the general population. Nonoperative treatment is a mainstay of management prior to surgical carpal tunnel release. Injections are frequently used as treatment, especially corticosteroid injections, but there is little consensus in the literature regarding injection number, volume, corticosteroid dose, and technique. Methods: A comprehensive literature search was performed of PubMed to identify papers relating to corticosteroid injections as well as other injections performed in patients with carpal tunnel syndrome. Results: A total of 45 articles were selected for inclusion in this review. Corticosteroid injections for carpal tunnel syndrome are discussed in detail, including injection number, volume, and technique as well as corticosteroid dose. Alternative injections for management of carpal tunnel syndrome are also discussed. Conclusions: Corticosteroid injections have been identified as a safe, effective short term management option for carpal tunnel syndrome. However, there is no standardized recommendation for specifics of their use in relation to corticosteroid dose, number of injections, injectate volume, and use of ultrasound guidance. Further research is required to better establish the optimal role for corticosteroid injections in the treatment of carpal tunnel syndrome. Platelet rich plasma, lidocaine, and hyaluronic acid, among others, are additional injections that warrant further exploration for use in management of carpal tunnel syndrome.

Management of Syndesmosis Injury: A Narrative Review.

The syndesmosis is an important fibrous joint that plays a crucial role in normal ankle weight-bearing and movements. Syndesmosis injuries include disruption of one or more of the ligaments comprising the distal tibiofibular syndesmosis and are commonly associated with ankle fractures. The treatment of grade 1 syndesmosis injury should be conservative, such as immobilization for one to three weeks followed by gradual return to activity. For the treatment of grade 2 syndesmosis injury, if it was stable enough, the patients still could be managed with conservative therapies. But majority of them strongly favor surgical treatment. For the treatment of grade 3 syndesmosis injury, it should treat with surgical reconstruction. If syndesmosis injury is associated with ankle fractures, surgical reduction, fixation, and reconstruction are usually required. Common surgical treatment methods include syndesmosis screws, composed of either metallic or bioabsorbable material; fibula intramedullary nails; and dynamic button-suture fixation, TightRope or ZipTight. Each method has advantages and disadvantages which must be considered while determining which treatment will provide the best outcomes depending on the patient's needs. Continued exploration of new materials, devices, and methods for surgical fixation is necessary for advancement in this field.

Surgical outcomes of periprosthetic distal femur fractures after total knee arthroplasty classified by Su et al. system.

Background: Periprosthetic fractures of the distal femur remain a challenge to treat due to variations in both patient- and fracture-specific factors. This study was designed to analyze the outcomes of different subtypes of periprosthetic distal femur fractures based on the Su et al. classification system. Methods: Thirty-six patients were classified with Su et al. system. All Type I and II fractures were managed with a locking plate. Most Type III fractures were managed with locking plate, while two were managed with long-stem revision arthroplasty due to evidence of implant loosening. Outcomes were measured and analyzed based on healing time, revision rate, and complication rate. Results: Of the 36 patients, 30 (83.3%) achieved acceptable fracture union, while the remaining 6 (16.7%) experienced either delayed union or non-union. Type I fractures showed a significantly lower healing time than Type II and III fractures managed by locking plate. Delayed union was present in the Type II group, while non-union was recorded for two Type III fractures. Need for revision was more prevalent in fracture Types II and III. Conclusion: The Su et al. system of classification for periprosthetic fractures of the distal femur matches the clinical outcomes of this study and would seem to be useful in the approach to the treatment of these fractures. The majority of these fractures can be managed with locking plate with reasonable results. However, if the implant is loosened in Type III fractures, revision arthroplasty is suggested.

A systematic review of the surgical outcomes of interprosthetic femur fractures.

Background: Interprosthetic femur fractures (IFFs) are rare, but the treatment is challenging. Currently, there are many treatment methods used in practice, but an updated systematic review of comparison of common different surgical outcomes has not been thoroughly inspected. Methods: A systematic review of retrospective studies was conducted. The resource databases of PubMed, Cochrane, and Embase were searched using a combination of the keywords involving IFFs and surgical outcomes from inception through June 2021. Data collected included patient demographics, intraoperative data, and postoperative outcomes. Outcomes were measured based on healing time, revision rate, complication rate, and functional scores. Results: Forty studies were included for review with a total of 508 patients. Average reported age of patients was 78.7 years old and 403 (79.3%) were females. Overall union rate was 74.0% with 376 of 508 patients achieving fracture union after primary treatment of IFF. Only 271 patients had reported healing times of fractures with a mean of 5.15 months. The plate, prosthetic revision, nail/rod, and external fixator groups had mean healing times of 4.69, 8.73, 6.5, and 5.1 months, respectively. Revision rates were highest in the femur replacement treatment group with 9 (32.1%) patients needing at least one reoperation surgery for any reason. Overall, hardware failure and non-unions were the most reported complications in treatment of IFFs. Postoperative functional outcome scores were available for 242 patients. Harris Hip Scores for the plate, revision, replacement, nail/rod, and plate + revision groups were 76.84, 77.14, 69.9, 77, and 78.4, respectively. Conclusion: Each treatment method should be carefully considered by the surgeon depending on the patient. Locking plate was the most common method for the treatment of the patients with IFFs. Half of them combined with cerclage wires/cables. Around two thirds' patients could achieve union with the fastest mean healing time around 4.69 months. Other less common methods included prosthetic revision, femur replacement, nail/rod, external fixator, etc. A small number of patients treated with Ilizarov external fixator, and it has proven to be a viable option with few complications and high union rates.

Managements of osteoporotic vertebral compression fractures: A narrative review.

Osteoporotic vertebral compression fractures (OVCFs) are the most common fragility fracture and significantly influence the quality of life in the elderly. Currently, the literature lacks a comprehensive narrative review of the management of OVCFs. The purpose of this study is to review background information, diagnosis, and surgical and non-surgical management of the OVCFs. A comprehensive search of PubMed and Google Scholar for articles in the English language between 1980 and 2021 was performed. Combinations of the following terms were used: compression fractures, vertebral compression fractures, osteoporosis, osteoporotic compression fractures, vertebroplasty, kyphoplasty, bisphosphonates, calcitonin, and osteoporosis treatments. Additional articles were also included by examining the reference list of articles found in the search. OVCFs, especially those that occur over long periods, can be asymptomatic. Symptoms of acute OVCFs include pain localized to the mid-line spine, a loss in height, and decreased mobility. The primary treatment regimens are pain control, medication management, vertebral augmentation, and anterior or posterior decompression and reconstructions. Pain control can be achieved with acetaminophen or nonsteroidal anti-inflammatory drugs for mild pain or opioids and/or calcitonin for moderate to severe pain. Bisphosphonates and denosumab are the first-line treatments for osteoporosis. Vertebroplasty and kyphoplasty are reserved for patients who have not found symptomatic relief through conservative methods and are effective in achieving pain relief. Vertebroplasty is less technical and cheaper than kyphoplasty but could have more complications. Calcium and vitamin D supplementation can have a protective and therapeutic effect. Management of OVCFs must be combined with multiple approaches. Appropriate exercises and activity modification are important in fracture prevention. Medication with different mechanisms of action is a critical long-term causal treatment strategy. The minimally invasive surgical interventions such as vertebroplasty and kyphoplasty are reserved for patients not responsive to conservative therapy and are recognized as efficient stopgap treatment methods. Posterior decompression and fixation or Anterior decompression and reconstruction may be required if neurological deficits are present. The detailed pathogenesis and related targeted treatment options still need to be developed for better clinical outcomes.

Syndesmosis screw breakage: An analysis of multiple breakage locations.

INTRODUCTION/PURPOSE: Concerns have been raised about screw breakage within the tibia or fibula, referred to as intraosseous breakage. The purpose of this investigation is to analyze the technical aspects of syndesmotic screw placement in multiple anatomic breakage locations. MATERIALS: A retrospective analysis of over 1056 patients who underwent syndesmosis fixation was completed. Demographics, screw length, width, number, height above the tibial plafond, angle, breakage location, and breakage location on the screw were collected and analyzed. RESULTS: Intraosseous (IO) screw breakage (91 screws, 68 patients) was more common than clear space (CS) breakage (28 screws, 18 patients) (P = < 0.001). Within the IO group, screw breakage within the tibia (60 screws, 52 patients) was more common compared to fibula breakage (29 screws, 24 patients) (P = < 0.001).Increased BMI and the use of multiple screws were associated with IO breakage (P = .007) and CS breakage (P = .012), respectively. Increased screw angle and age were associated with fibular IO breakage (P = .021, P = .036) when compared to other IO breakage locations. Screw angle and placement showed no significant differences between compared groups (P = .629, P = .570). CONCLUSION: Syndesmosis screw breakage, overall, occurred more commonly in an IO location. When compared to IO breakage, the use of multiple syndesmosis screws is most associated with CS breakage. Increased BMI is associated with increased IO breakage when compared to CS breakage. Patients with IO screw breakage within the fibula had increased age and placed at a higher angle when compared to other IO breakage locations. No other factors related to screw placement, including the height of placement, were found to be significantly associated with location of screw breakage.

Surgical outcomes of subtypes of periprosthetic tibia fractures after total knee arthroplasty.

Surgical outcomes of subtypes of periprosthetic tibia fractures after total knee arthroplasty were evaluated by using the Felix et al. classification system. Type 3 fractures were the most common classification of periprosthetic tibial fractures. Type 2 fractures had the highest rates of revision and nonunion. Type 3 fractures exhibited longer healing times than types 2 and 4. Far type 3 fractures showed the longest healing time of all fracture types but had very minimal complications. Type 4 fracture managed by K-wire/cerclage wire may require hardware removal or debridement but exhibited the shortest healing time compared to types 2 and 3.

Arthrodesis or Open Reduction Internal Fixation for Lisfranc Injuries: A Meta-analysis.

The purpose of this study is to determine if arthrodesis, compared with open reduction and internal fixation (ORIF), produces favorable American Orthopaedic Foot and Ankle Society (AOFAS) and visual analogue scale (VAS) scores, and to determine if differences in complication, revision surgery, and secondary arthrodesis rates exist for patients with Lisfranc fracture/dislocation injuries. Searches were performed in PubMed using the keywords "Lisfranc fracture," "metatarsal fracture," "ORIF," "open reduction internal fixation," "arthrodesis," and "fusion." These criteria left 183 articles for review. Exclusions left 21 articles and 2 translations of Chinese abstracts. Data analysis was performed using Student's 2-sample t test for samples of equal variance, and chi-square test for goodness of fit. The t test revealed a significant difference (P = .03) between the average AOFAS score for patients who underwent primary arthrodesis (84.7 ± 6.14) compared with those who were treated with ORIF (78.9 ± 5.09). There was no significant difference for the average VAS scores (P = .33) of the arthrodesis and ORIF groups. The complication rate of arthrodesis patients was significantly lower than ORIF patients (P = .04), and the rates of revision surgery (P = .22) and secondary arthrodesis (P = .53) were not significant between the groups. The results of this study indicate that arthrodesis may be a better surgical option than ORIF, due to the higher functional scores and the lower complication rate.Levels of Evidence: Level III: A meta-analysis.

Sacroiliitis: A Review on Anatomy, Diagnosis, and Treatment.

Introduction: Sacroiliitis is an inflammation of one or both of the sacroiliac (SI) joints, most often resulting pain in the lower back that can extend down the legs. Pain arising from the SI joint can be difficult to diagnose and treat due to the intricate surrounding ligamentous structure, nerve innervation, and its role in transferring weight from the upper body to the lower limbs. SI joint dysfunction accounts for up to 25% of cases of lower back pain and has a debilitating effect on patient functionality. This review aims to provide comprehensive coverage of all aspects of SI joint pain, with a specific focus on differential diagnosis and treatment. Methods: Current literature on SI joint pain and inflammation, other etiologies of lower back pain, and new treatment options were compiled using the databases PubMed and Cochrane and used to write this comprehensive review. There were no restrictions when conducting the literature search with regard to publication date, study language, or study type. Results: The diagnosis protocol of SI joint pain arising from sacroiliitis usually begins with the presentation of lower back pain and confirmatory diagnostic testing through fluoroscopy joint block. Reduction in pain following the anesthetic is considered the golden standard for diagnosis. The treatment begins with the conservative approach of physical therapy and analgesics for symptom relief. However, refractory cases often require interventional methods such as corticosteroid injections, prolotherapy, radiofrequency ablation, and even SI joint fusion surgery. Conclusion: SI joint pain is a complex problem that can present with varying patterns of pain due to uncertainty regarding its innervation and its prominent surrounding structure. It is therefore especially important to obtain a thorough history and physical on top of diagnostic tests such as a diagnostic block to properly identify the source of pain. Conservative treatment options with physical therapy and analgesics should be attempted first before interventional strategies such as ablation, injections, and prolotherapy can be considered. SI joint fusion surgery is a solution to cases in which previous methods do not provide significant relief.

Surgical outcomes of non-periprosthetic distal femur fragility fractures treated with a locking plate.

Background: Management of distal femur fractures can be challenging, particularly in the aged female population. This retrospective study aims to analyze the surgical outcomes of aged female patients with non-periprosthetic distal femur fractures treated with a locking plate. Methods: This is an IRB approved retrospective review conducted at a level 1 trauma center. Fifty-five female patients (mean age of 71 years) with non-periprosthetic distal femur fractures underwent open reduction internal fixation using a locking plate from 2005 to 2019. The average follow-up time was 67 weeks from the date of injury. Criteria used for diagnosis of nonunion included one or more of the following: (I) three consecutive months without progression of healing on postoperative radiographs, (II) a total of nine months postoperative without complete healing, or (III) the physician diagnosed nonunion using clinical judgement. Outcome data was analyzed and compared amongst patients with and without obesity or diabetes. Statistical analysis was performed utilizing Microsoft Excel 2022 Data Analysis ToolPak with a standard statistically significant P value of <0.05. Results: Thirty-two patients (58%) with distal femur fractures achieved union after initial treatment while 23 patients (42%) were diagnosed with nonunion. Fourteen patients (61%) underwent revision with 9 of these patients (64%) achieving union while 5 patients (36%) had persistent nonunion. Average healing time from initial treatment to union was 29 weeks, while average time from definitive treatment to union was 22 weeks. Obese patients [body mass index (BMI) >30 kg/m2] had a nonunion rate of 65%, while non-obese patients had a nonunion rate of 28%. Patients with diabetes had a nonunion rate of 65%, while patients without diabetes had a nonunion rate of 28%. Conclusions: Union can be successfully achieved in aged female patients with distal femur fractures treated with locking plates; however, the risks for nonunion and revision remain high. Patients with obesity and diabetes appear to be at an increased risk of nonunion (P=0.008 and 0.008, respectively). However, further research should be conducted with a prospective study or multivariate analysis and increased number of patients to reaffirm this data.

Interventions for Distal Radius Fractures: A Meta-analysis of Comparison Studies.

Background Distal radius fractures are one of the most frequent orthopaedic injuries. There are many effective treatment methods, such as volar plate, dorsal plate, percutaneous pins, external fixation, and casting; however, comparison of the treatment outcomes has not been thoroughly investigated. Our purpose is to determine if volar plating is the superior treatment method for distal radius fractures. We will address this through the following questions: First, is volar plating superior to dorsal plating, percutaneous pins, external fixation, or casting in terms of reported complications? Second, does volar plating produce superior functional outcomes to dorsal plating, percutaneous pins, external fixation, or casting? Third, are the radiographic outcomes superior for volar plating when compared with dorsal plating, percutaneous pins, external fixation, or casting? Methods MEDLINE, Academic Search Ultimate, Academic Search Complete, CINAHL Plus, and JSTOR databases, as well as manual search, were used to identify papers comparing complications and functional results of volar plating to other treatment methods for distal radius fractures published after the year 2000. Complication data and function scores were recorded. Risk of bias was assessed using the Cochrane Risk of Bias Tool and data was analyzed for meta-analysis using Cochrane ReviewManager software. Results Compared with dorsal plate, volar plate performed significantly better in Gartland and Werley score. Volar plating outperformed percutaneous pins for loss of reduction, infection, Disabilities of the Arm, Shoulder, and Hand (DASH) score, and ulnar deviation. Loss of reduction, malunion, Patient Related Wrist Evaluation (PRWE) score, DASH score, grip strength, ulnar deviation, and supination were significantly better for volar plating when compared with casting. When compared with external fixation, volar plating had significantly less cases of infection, lower QuickDASH score, and higher range of motion for flexion, pronation, and supination. All other complication and functional outcomes were not significantly different. Conclusions Distal radius fractures treated with volar plating showed relatively better measures of complications, function scores, and range of motion than other treatment methods; however, there was no significant difference in healing time when compared with percutaneous pins. More studies are needed to compare the rest of the treatment methods with each other.

Biomechanical comparison of suture-button, bioabsorbable screw, and metal screw for ankle syndesmotic repair: A meta-analysis.

BACKGROUND: To compare biomechanically metal screw fixation to suture-button or bioabsorbable screw fixation for ankle syndesmotic injuries. METHODS: A literature search of the comparison studies in Pubmed and Google Scholar was conducted. The biomechanical outcomes of interest were syndesmotic stability in the coronal, sagittal, and axial planes as well as torque and rotation at failure. RESULTS: A total of 11 cadaveric studies were included. In the suture-button group, coronal displacement (MD 1.72mm, p = 0.02) and sagittal displacement (MD 2.65mm, p = 0.0003) were increased relative to the metal screw group. In contrast, no difference was found with axial rotation (MD 0.35 degrees, p = 0.57). Bioabsorbable screws exhibited equivalent failure torque (MD -3.04Nm, p = 0.53) and rotation at failure (MD 3.77 degrees, p = 0.48) in comparison to metal screws. CONCLUSIONS: Suture-button provide less rigidity when compared to metal screw fixation. They afford flexible syndesmotic micromotion which may more closely resemble a physiological state and be helpful for ligament healing. Bioabsorbable screws demonstrate similar mechanical strength properties to metal screws.

Nonenzymatic and Trophic Activities of Carboxypeptidase E Regulate Bone Mass and Bioenergetics of Skeletal Stem Cells in Mice.

Bone and energy metabolism are integrated by common regulatory mechanisms. Carboxypeptidase E (CPE), also known as obesity susceptibility protein or neurotrophic factor-α1, is recognized for its function in processing prohormones, including proinsulin and pro-opiomelanocortin polypeptide. Independent of its enzymatic activity, CPE may also act as a secreted factor with divergent roles in neuroprotection and cancer growth; however, its role in the regulation of bone mass and skeletal cell differentiation is unknown. Male mice with global deficiency in CPE are characterized with profound visceral obesity, low bone mass in both appendicular and axial skeleton, and high volume of marrow fat. Interestingly, although metabolic deficit of CPE KO mice develops early in life, bone deficit develops in older age, suggesting that CPE bone-specific activities differ from its enzymatic activities. Indeed, mutated CPE knockin (mCPE KI) mice ectopically expressing CPE-E342Q, a mutated protein lacking enzymatic activity, develop the same obese phenotype and accumulate the same volume of marrow fat as CPE KO mice, but their bone mass is normal. In addition, differentiation of marrow hematopoietic cells toward tartrate-resistant acid phosphatase-positive multinucleated osteoclasts is highly increased in CPE KO mice, but normal in mCPE KI mice. Moreover, in murine skeletal stem cells, nonenzymatic trophic CPE has activated ERK signaling, increased cell proliferation and increased mitochondrial activity. Treatment of preosteoblastic cells with intact or mutated recombinant CPE led to a transient accumulation of small lipid droplets, increased oxidative phosphorylation, and increased cellular dependence on fatty acids as fuel for energy production. In human marrow aspirates, CPE expression increases up to 30-fold in osteogenic conditions. These findings suggest that nonenzymatic and trophic activities of CPE regulate bone mass, whereas marrow adiposity is controlled by CPE enzymatic activity. Thus, CPE can be positioned as a factor regulating simultaneously bone and energy metabolism through a combination of shared and distinct mechanisms. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Surgical Treatment of a Chronic Morel-Lavallée Lesion: A Case Report.

INTRODUCTION: Morel-Lavallée lesions (MLLs) are a post-traumatic degloving injury which the superficial fascia and skin are separated from the deep fascia through shearing forces. This process leads to the development of a potential space in which blood products and necrotic material can collect, potentially resulting in abscesses, cellulitis, or osteomyelitis. Most of these cases occur at the greater trochanter, gluteal musculature, proximal femur, and around the knee. However, there have been few reports of MLLs occurring in the lumbar region. In this report, we seek to present our experience with a case of a lumbar MLL and outline the diagnostic and operative management utilized. CASE REPORT: A 48-year-old female presented to our clinic with complaints of persistent low back and swelling 1 month after sustaining a fall from stand resulting in an L5 transverse process fracture. The patient was treated non-operatively but continued to have swelling noted to the lower back. A computed tomography scan demonstrated a large subcutaneous fluid collection measuring 15 cm×16 cm×7 cm centralized over the lower lumbar region. We elected to proceed with operative evacuation of the fluid collection. A 2 cm midline incision over the proximal aspect of the fluid collection was made and approximately 900 ml of serosanguinous fluid was evacuated. The cavity was then irrigated with a normal saline 0.9%/betadine solution and a wound vacuum-assisted closure (VAC) sponge was placed. The post-operative course was unremarkable and the wound VAC was discontinued at the first post-operative visit. The surgical incision went on to heal uneventfully with no signs of infection or fluid reaccumulation. CONCLUSION: Although MLLs are rare, clinicians should maintain a high clinical suspicion in patients presenting after blunt trauma injuries with persistent pain, and fluid collections noted on advanced imaging. Conservative management can be initiated if discovered acutely, but if left untreated may require surgical intervention and evacuation of fluid as described in this case.

Teres minor and quadrilateral space syndrome: A review.

The teres minor is one of four rotator cuff muscles that is involved in many shoulder pathologies. The integrity of the teres minor can be indicative of treatment success for disorders including rotator cuff tears, impingement syndrome, and quadrangular space syndrome. Quadrangular or quadrilateral space syndrome is a debilitating disorder that may require surgical intervention in chronic cases and can lead to atrophy of the teres minor. A review of the diagnostic techniques and treatment methods for disorders involving teres minor, with a focus on quadrilateral space syndrome, are presented in order to summarize the current understanding of these pathologies.

Revision of Syndesmosis Screw Fixation.

Background: Many syndesmosis screw fixations do not achieve success at the first attempt. Currently, there are no data available to evaluate revision of syndesmosis screw failure. Methods: A total of 160 consecutive patients who underwent syndesmosis screw fixation from 2014 to 2016 were reviewed. The current study focuses on 13 of 160 patients who underwent revision surgery and analyzes reasons, methods, and outcomes of syndesmotic screw revisions. Results: Thirteen out of 160 patients had revision surgeries. Incidence of recurrent diastasis was 92.3%. Seven out of 19 screws had broken. Two patients had screw loosening, 9 patients underwent early weightbearing, 1 patient developed osteomyelitis, 1 patient developed osteoarthritis, and 1 patient had fibular nonunion. Eleven patients underwent removal, 3 patients underwent clamp reduction, and 4 patients underwent fibular osteotomy. Six patients experienced good reduction with 0/10 pain, 3 patients experienced good reduction with some pain, 1 patient experienced poor reduction; 1 patient developed osteomyelitis and subsequent 7/10 pain; 1 patient underwent fusion with 5/10 pain, and 1 patient experienced medial malleolar mal-union with 3/10 pain. Conclusion: It was found that the main reason for syndesmosis revision was reoccurring diastasis. Most patients ultimately experienced good reduction and were able to ambulate, despite some residual pain. Levels of Evidence: Level IV: Case series.