Suspected gluteal compartment syndrome: Etiology predicts clinical course, outcomes and resource utilization

Background

Gluteal Compartment Syndrome (GCS) is a rare subtype of acute compartment syndrome (ACS), complex to diagnose and potentially fatal if left untreated. The incidence of ACS is estimated to be 7.3 per 100,000 in males and 0.7 per 100,000 in females [1-3]. Given its rare occurrence, the incidence of GCS is not well reported. In the case of GCS, the most common etiologies are surgical positioning, prolonged immobilization secondary to substance use or loss of consciousness, and traumatic injury. Clinical findings are pulselessness, pallor, parasthesia, paralysis, and most notably pain out of proportion. Swift diagnosis and treatment are imperative to reduce morbidity and mortality, however the ideal management of GCS is difficult to ascertain given the rare occurrence and variable presentation.

Methods

Orthopaedic trauma database at a level 1 trauma center was reviewed to identify patients for whom the orthopaedic service was consulted due to suspicion of gluteal compartment syndrome. This yielded 11 patients between 2011 and 2019. Patients with a measured ΔP greater than 30 upon initial consultation and with a concerning exam requiring monitoring were included. Patient demographics, comorbidities, GCS etiology, laboratory values, physical exam findings, pain scores (0-10) and patient outcomes were collected via chart review. Patient demographic and injury characteristics were summarized using descriptive statistics.

Results

Prolonged immobilization patients had worse outcomes including longer hospital stays (40.5 days) compared to trauma patients (4.5 days). All adverse medical outcomes recorded including acute renal failure, prolonged neuropathic pain, cardiopulmonary dysfunction were exclusively experienced by prolonged immobilization patients.

Conclusions

Our descriptive study demonstrates the bimodal distribution of GCS patients based on etiology. Prolonged immobilization patients have a longer hospital course and more complications. Our study confirms prior reports and provides information that can be used to counsel patients and families appropriately about treatment and recovery following GCS.

Level of evidence

IV.

Study type

Epidemiological.

Does Anterior Plating of Pelvic Ring Fractures Increase Infection Risk in Patients With Bladder or Urethral Injuries?

OBJECTIVES

Evaluate the effect of anterior fixation on infection in patients with operative pelvic fractures and bladder or urethral injuries.

METHODS

DESIGN

Retrospective.

SETTING

Eight centers.

PATIENT SELECTION CRITERIA

Adult patients with closed pelvic fractures with associated bladder or urethral injuries treated with anterior plating (AP), intramedullary screw (IS), or no anterior internal fixation (NAIF, including external fixation or no fixation).

OUTCOME MEASURES AND COMPARISONS

Deep infection.

RESULTS

There were 81 extraperitoneal injuries and 57 urethral injuries. There was no difference in infection between fixation groups across all urologic injuries (AP: 10.8%, IS: 0%, NAIF: 4.9%, P = 0.41). There was a higher rate of infection in the urethral injury group compared with extraperitoneal injuries (14.0% vs. 2.5%, P = 0.016). Among extraperitoneal injuries, specifically, there was no difference in deep infection related to fixation (AP: 2.6%, IS 0%, NAIF: 2.9%, P = 0.99). Among urethral injuries, there was no statistical difference in deep infection related to fixation (AP: 23.1%, IS: 0%, NAIF: 7.4%, P = 0.21). There was a higher rate of suprapubic catheter (SPC) use in urethral injuries compared with extraperitoneal injuries (57.9% vs. 4.9%, P < 0.0001). In the urethral injury group, SPC use did not have a statistically significant difference in infection rate (SPC: 18.2% vs. No SPC: 8.3%, P = 0.45). Early removal of the SPC before or during the definitive orthopaedic intervention did not significantly affect infection rate (early: 0% vs. delayed: 25.0%, P = 0.16).

CONCLUSIONS

Surgeons should approach operative pelvic fractures with associated urologic injuries with caution given the high risk of infection. Further work must be done to elucidate the effect of anterior implants and SPC use and duration.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Acute Presentation of a Pseudoaneurysm After a Proximal Humerus Shaft Fracture: A Case Report

CASE

A 69-year-old woman presented with a brachial artery pseudoaneurysm causing median, ulnar, and radial nerve compressive neuropathies 8 weeks after a proximal humerus shaft fracture treated with intramedullary nailing. She underwent a brachial artery bypass with a reverse cephalic vein interposition graft and neurolysis after decompression of a large pseudoaneurysm. Postoperatively, the patient had a normal vascular examination with recovering neurological function.

CONCLUSIONS

A high index of suspicion for a brachial artery pseudoaneurysm should be maintained in patients with a displaced proximal humerus shaft fracture, particularly when an abnormal neurovascular examination is present.

Catastrophic Failure of the Acetabular Polyethylene Liner in Ceramic-on-Polyethylene Total Hip Arthroplasty

Introduction:

Catastrophic polyethylene failure is a rare complication of ceramic-on-polyethylene total hip arthroplasty due to the favorable tribological characteristics of ceramic. Failure of the polyethylene liner can be disastrous, increasing periprosthetic osteolysis, metallosis, and risk of dislocation. Complications associated with ceramic-on-polyethylene articulations have been studied extensively, however, only few reports have described its catastrophic wear. We report such a case of complete wear of the acetabular liner in a ceramic-on-polyethylene prosthesis in a 57-year adult male.

Case Report:

A 57-year adult male with a history of bilateral total hip arthroplasty presented to our institution with bilateral hip pain worst on the right. Range of motion was limited by pain on the right hip at the extremes of motion. Radiographs revealed severe osteolysis, heterotopic ossification, complete wear of the acetabular liner, bony impingement of the femoral greater trochanter on the acetabular rim and superior migration of the femoral head. All findings were confirmed intraoperatively. Revision of the acetabular components was performed, which successfully alleviated the patient’s symptoms.

Conclusion:

Failure of the ceramic-on-polyethylene liner in our patient is due to the use of a non-cross linked polyethylene liner, a highly active lifestyle, and poor follow up. Arthroplasty surgeons should be aware of this complication especially in highly active patients with a conventional polyethylene liner and chronic hip pain.

Comparison of tissue oxygenation and compartment pressure following tibia fracture

OBJECTIVE

We investigated the ability of direct continuous measurement of intramuscular tissue oxygenation (PmO(2)) to detect acute ischaemia in the leg in patients at risk for acute extremity compartment syndrome. Following tibia fracture treated by intramedullary nailing, we compared the proportions of PmO(2) and compartment pressure (CP) measurements that met the warning criteria for compartment syndrome.

METHODS

Participants included 10 patients sustaining acute isolated closed tibia shaft fractures treated by intramedullary nailing. A tissue oxygenation probe and a CP probe were percutaneously placed into the anterior compartment of the leg. PmO(2) and CP in the anterior compartment were measured in the injured leg for 48 h postoperatively. Measurements meeting the warning criteria were defined as PmO(2) < 10 mmHg, CP > 30 mmHg and perfusion pressure ΔP < 30 mmHg.

RESULTS

None of the patients developed compartment syndrome. Comparison of CP and PmO(2) showed a CP > 30 mmHg in 50.39% of CP measurements in all patients and a PmO(2) < 10 mmHg in 0.75% of PmO(2) measurements in two patients (P = 0.005). Comparison of ΔP and PmO(2) showed a ΔP < 30 mmHg in 31.01% of ΔP measurements in nine patients and a PmO(2) < 10 mmHg in 0.76% of PmO(2) measurements in one patient (P = 0.01).

CONCLUSION

In the absence of compartment syndrome, pressure measurements following tibia fracture treated with intramedullary nailing often met the warning criteria, whereas PmO(2) did not, suggesting that measurement of intramuscular tissue oxygenation may represent a potential method for the identification of acute compartment syndrome that deserves continued investigation.

Nerve allografts and conduits in peripheral nerve repair

Since the last update on nerve conduits and allograft in 2000, investigations have established the efficacy of these alternatives to autograft in the repair of small sensory neural gaps. However, limited insights into the biology of the regenerating nerve continue to preclude intelligent conduit design. Ongoing discoveries in neuroscience and biomaterial engineering hold promise for the eventual development of allograft and conduits with potential of surpassing nerve autografts in clinical efficacy. In this review, we summarize the history, recent advances, and emerging developments in nerve conduits and allograft.

Original article Muscle extracellular matrix degradation and contractibility following tendon rupture and disuse

Muscle extracellular matrix (ECM) plays an important role in maintaining muscular integrity and force transduction. However, the role of ECM in skeletal muscle atrophy remains unknown. In this study, we employed two clinically relevant mouse models of Achillotenotomy and hindlimb suspension to simulate Achilles tendon rupture and hindlimb disuse. The gastrocnemius was harvested following two weeks of treatment. We hypothesized that degradation of muscle ECM basement membrane lead to dysfunction of muscle contractility. Our results demonstrated a significant reduction of gastrocnemius single twitch force, isometric tetanic force, and contraction velocity following tendon rupture (p<0.001), but not disuse. Additionally, up-regulation of matrix metalloproteinase-2 (MMP-2) was observed only after tendon rupture (p=0.00234). These findings suggest that ECM remodeling and basement membrane degradation due to MMP-2 may be responsible for declined muscle contractibility. Inhibiting ECM degradation enzymes may be a potential treatment strategy for skeletal muscle atrophy after tendon rupture.

A comparison of lidocaine, ropivacaine and dexamethasone toxicity on bovine tenocytes in culture

Peri-tendinous injection of local anaesthetic, both alone and in combination with corticosteroids, is commonly performed in the treatment of tendinopathies. Previous studies have shown that local anaesthetics and corticosteroids are chondrotoxic, but their effect on tenocytes remains unknown. We compared the effects of lidocaine and ropivacaine, alone or combined with dexamethasone, on the viability of cultured bovine tenocytes. Tenocytes were exposed to ten different conditions: 1) normal saline; 2) 1% lidocaine; 3) 2% lidocaine; 4) 0.2% ropivacaine; 5) 0.5% ropivacaine; 6) dexamethasone (dex); 7) 1% lidocaine+dex; 8) 2% lidocaine+dex; 9) 0.2% ropivacaine+dex; and 10) 0.5% ropivacaine+dex, for 30 minutes. After a 24-hour recovery period, the viability of the tenocytes was quantified using the CellTiter-Glo viability assay and fluorescence-activated cell sorting (FACS) for live/dead cell counts. A 30-minute exposure to lidocaine alone was significantly toxic to the tenocytes in a dose-dependent manner, but a 30-minute exposure to ropivacaine or dexamethasone alone was not significantly toxic.

Dexamethasone potentiated ropivacaine tenocyte toxicity at higher doses of ropivacaine, but did not potentiate lidocaine tenocyte toxicity. As seen in other cell types, lidocaine has a dose-dependent toxicity to tenocytes but ropivacaine is not significantly toxic. Although dexamethasone alone is not toxic, its combination with 0.5% ropivacaine significantly increased its toxicity to tenocytes. These findings might be relevant to clinical practice and warrant further investigation.

A mouse model of massive rotator cuff tears

BACKGROUND

Rotator cuff tears are the most common tendon injury seen in orthopaedic patients. Muscle atrophy and fatty infiltration in rotator cuff muscles are considered among the key factors responsible for the failure of attempted repair of a massive rotator cuff tear. However, the pathophysiology of rotator cuff muscle atrophy and fatty infiltration remains largely unknown, partly because of the lack of appropriate small animal models. The goal of this study was to develop a mouse model of muscle atrophy and fatty infiltration after a rotator cuff tear. We also sought to study the role of denervation on muscle atrophy and fatty infiltration after a rotator cuff tear.

METHODS

Adult wild-type FVB/N mice were randomly divided into three groups. Mice in different groups received unilateral complete supraspinatus and infraspinatus tendon transection, suprascapular nerve transection, or both procedures. Sham surgery was performed on the contralateral shoulder to serve as a control. Mice were killed twelve weeks after surgery. Histological analysis and high-resolution magnetic resonance imaging were used to evaluate muscle atrophy and fat infiltration after a rotator cuff tear.

RESULTS

Significant and consistent muscle atrophy and fatty infiltration were observed in the rotator cuff muscles after rotator cuff tendon transection. We further found that denervation significantly increases the amount of muscle atrophy and fatty infiltration after a rotator cuff tear.

CONCLUSIONS

We successfully developed a novel mouse model of a massive rotator cuff tear, which simulates major pathological changes, including muscle atrophy and fatty infiltration after massive rotator cuff tears seen in patients.

A rat model of massive rotator cuff tears

Rotator cuff tears (RCTs) are the most common tendon injury seen in orthopedic patients. Massive RCT does not heal spontaneously and results in poor clinical outcomes. Muscle atrophy and fatty infiltration in rotator cuff muscles are major complications of chronic massive RCT and are thought to be the key factors responsible for the failure of attempted massive RCT repair. However, the pathophysiology of rotator cuff muscle atrophy and fat infiltration remains largely unknown, and no small animal model has been shown to reproduce the histologic and molecular changes seen in massive RCT. In this article, we report a novel rat massive RCT model, in which significant and consistent muscle atrophy and fat infiltration were observed in the rotator cuff muscles after rotator cuff tendon transection and denervation. The supraspinatus and infraspinatus muscle lost 25.4% and 28.9% of their wet weight 2 weeks after complete tendon transection, respectively. Six weeks after surgery, the average wet weight of supraspinatus and infraspinatus muscles decreased 13.2% and 28.3%, respectively. Significant fat infiltration was only observed in infraspinatus 6 weeks after tendon transection.

Bovine tuberculosis in wild boar (Sus scrofa), red deer (Cervus elaphus) and cattle (Bos taurus) in a Mediterranean ecosystem (1992–2004)

During the last 12 years, an increasing frequency in condemnation of hunted red deer and wild boar carcasses due to the presence of tubercle-like lesions has been observed in Extremadura (Western Spain). Before 1993, tuberculosis was a very rare finding in hunted animals. The current tuberculosis regional prevalence in cattle approaches 0.4% after years of expensive test and slaughter campaigns. It is imperative to investigate the epidemiology of Mycobacterium bovis infection in red deer and wild boar in order to keep a good health status and to maintain the effectiveness of domestic species TB eradication programs. The present paper evaluates the problem in Sierra de San Pedro, estimating the prevalence of TB in wild boar and red deer, the main wild artiodactyls in the area, and domestic cattle since 1992-2004, by the use of a low-cost surveillance method based on detailed pathological inspection of hunted animal carcasses. Microbiology and molecular epidemiology studies on several M. bovis isolates from domestic and wild animals helped to define the interspecies contacts. These findings, as well as recent history of game estates management and descriptive epidemiology field work, throw light on the rise and maintenance of these epizootics.

Longitudinal structure and innervation of two mammalian hindlimb muscles

The possibility of a topographic relationship between the spinal cord and the longitudinal axis of a muscle has been explored in two mammalian hamstring muscles: the rat semitendinosus (ST) and biceps femoris (BF). In both muscles the fibers did not extend the full length of the respective muscle bellies but were arranged in longitudinal arrays. There were two such arrays in BF and three in ST; monopolar recordings revealed that each array had a transverse band of endplates extending across the middle part. By stimulating ventral nerve roots in the lumbosacral outflow, it was found that L5 made the greatest contribution to the innervation of both ST and BF, with lesser inputs coming from adjacent roots. In neither ST or BF was there any evidence of a topographic relationship between the spinal cord and the muscle belly.

Multiple innervation of human muscle fibers

A combination of electrophysiological techniques, including stimulus threshold measurements, coaxial needle recordings of voluntary EMG, and evoked response analysis, has been used to show that the motor innervation of the human biceps brachii has an extensive distribution in the long axis of the muscle. Impulse collision experiments, involving either excitation at two sites or the use of stimuli of graded intensity, have demonstrated that the diffuse muscle innervation is partly a consequence of individual muscle fibers having more than one end-plate.

Impulse conduction velocities in human biceps brachii muscles

Measurements of impulse conduction velocity were made in biceps brachii muscle fibers of male or female controls and of male body-builders. The technique involved exciting bundles of fibers with stimulating electrodes applied over the surface of the muscle, and recording compound action potentials with three small surface electrodes spaced 3 cm apart. By measuring latencies to the onsets and to the peaks of the negative deflections, it was possible to estimate conduction velocities in the fastest-conducting (FC) and intermediate-conducting (IC) fibers; the observed values ranged from 2.8 to 5.5 m X s-1 in normal men and women. The mean conduction velocity for FC fibers was significantly higher in body-builders than in normal men and women; the mean IC value was significantly lower in women. In all three groups of subjects a decrease in conduction velocity could be demonstrated for FC fibers at the end of 1 min of maximal isometric contraction. In the body-builders, and probably in the other two groups of subjects, the FC fibers are considered to correspond to type II muscle fibers.