The tricipital aponeurosis--a reliable soft tissue landmark for humeral plating.

This study aims to identify the relationship of the radial nerve as it descends across the humerus with reference to a reliable soft tissue landmark, the tricipital aponeurosis. Following cadaveric dissection of 10 adult humerii, the radial nerve was located as it crossed the lateral midsagittal point of the humeral diaphysis. A horizontal line was then subtended medially from this point to another line subtended vertically from the lateral border of the tricipital aponeurosis. The vertical distance from this intersection to the lateral apex of the aponeurosis was recorded in three positions (full flexion, 90° of flexion and full extension). The location of the radial nerve on the posterior aspect of the humeral diaphysis to the medial apex of the tricipital aponeurosis was also noted. In 90° of flexion the radial nerve at the lateral midsagittal point of the humerus was 0.9 mm proximal to the lateral apex of the tricipital aponeurosis. Flexion and extension of the elbow changed the interval to 16.3 mm (nerve proximal) in full flexion and 7.1 mm in full extension (nerve distal). On the posterior aspect of the humerus the radial nerve was 21.8 mm proximal to the medial aspect of the tricipital aponeurosis. The aponeurosis provides a reference point from which the nerve can be easily located on the lateral aspect of the humerus intraoperatively in a range of positions, whilst the medial apex provides a guide to the location of the nerve on the posterior aspect of the arm.

Reverse geometry shoulder replacement for proximal humeral metastases.

The management of skeletal metastases can be challenging for the orthopaedic surgeon. They represent a significant source of pain and disability for cancer patients, adding to the morbidity of their condition. Treatment is directed at the alleviation of symptoms and the restoration of function. Metastatic involvement of the proximal humerus can be especially debilitating, having the potential to cause severe pain and loss of function. We present a report of three such cases where reverse geometry proximal shoulder replacement was used to provide a pain free functional range of movement in patients with concomitant rotator cuff disease. In all cases, significant symptomatic relief was achieved postoperatively with preservation of upper limb function. No surgical complications were noted. It is our belief that this novel surgical strategy provides a valuable and effective option for the management of proximal humeral metastatic disease in the rotator cuff deficient patient.

The effect of ultrasound guided steroid injection on progression to surgery in thumb CMC arthritis.

Thumb carpometacarpal joint (CMCJ) osteoarthritis is a common complaint that produces pain and disability within the hand. This study aims to ascertain whether joint injection with local anaesthetic and steroid is of predicative value in disease progression in thumb carpometacarpal osteoarthritis. Forty-three patients were assessed at an average follow up of 24 months following ultrasound-guided injection. Fourteen patients (32%) progressed to surgery, at a mean interval of 8.6 months (range 4-14 months). There was a statistically significant correlation between those patients who had on-going pain following injection at one week and progression to surgery (p = 0.025) with an odds ratio of 3.14 and positive likelihood ratio of 2.1. Patients with thumb CMCJ osteoarthritis that does not respond favourably to injection at one week are likely to progress to surgery in the first year after the injection. This work offers a useful tool in predicting disease progression and patient counseling.

Contrast enhanced ultrasound (CEUS) reliably detects critical perfusion changes in compartmental muscle: a model in healthy volunteers.

PURPOSE: The purpose of this study was to assess the utility of contrast enhanced ultrasound (CEUS) in the differentiation between physiological and simulated pathophysiological lower limb muscle perfusion pressures in healthy volunteers. METHODS: The lower limb muscle perfusion pressures in eight healthy volunteers were assessed in the supine position (as a control) and then subsequently in an elevated position with a thigh tourniquet applied to induce venous stasis. An intravenous bolus injection of 2.5 ml contrast agent was given to create a perfusion signal, which was measured with a multiple-frequency probe. Semiquantitative analysis was performed using specific software to create a perfusion curve which allowed measurement of six parameters: the time to arrival (TTA) starting from bolus application (s); peak of signal intensity (%); time to peak (TTP) maximum (seconds); regional blood volume (RBV), regional blood flow (RBF), and mean transit time (MTT) in seconds. Statistical analysis was performed using the Mann-Whitney U test as a non-parametric test (IBM SPSS statistics, version 21, USA). RESULTS: The group of simulated hypoperfusion showed significant higher values for TTA (39.8 ± 5.1 s) (p = 0.028), TTP (43.8 ± 13.6 s) (p = 0.003), RBV (8,424 ± 5,405) (p = 0.028), and MTT (262 ± 90.6 s) (p = 0.005). In contrast, the parameter of regional blood flow (32.1 ± 10.9) was significantly lower (p = 0.038). The peak signal intensity (25.8 ± 8.2 %) was lower, but this was not significant (p = 0.083). CONCLUSIONS: CEUS provides a reliable non-invasive imaging modality for the assessment of lower limb muscle perfusion pressures. This may be of clinical use in the assessment of a developing compartment syndrome. Further clinical studies are required to further define its accuracy and reproducibility.

Functional outcome following tibio-talar-calcaneal nailing for unstable osteoporotic ankle fractures.

INTRODUCTION: Fragility fractures of the ankle are increasing in incidence. Such fractures typically occur from low-energy injuries but lead to disproportionately high levels of morbidity. Ankle fractures in this age group are managed conservatively in plaster or by open reduction and internal fixation. Both modalities have shown high rates of failure in terms of delayed union or mal-union together with perioperative complications such as implant failure and wound breakdown. The optimal treatment of these patients remains controversial. OBJECTIVES: We aimed to review the functional outcome of patients with ankle fragility fractures primarily managed using a tibio-talar-calcaneal nail (TTC). METHODS: We retrospectively reviewed 31 consecutive patients primarily managed with a TCC nail for osteoporotic fragility fractures about the ankle. Data were collected via case notes, radiographic reviews and by clinical reviews at the outpatient clinic or a telephone follow-up. Information regarding patient characteristics, indication for operation, Arbeitsgemeinschaft für Osteosynthesefragen (AO) fracture classification, operative and postoperative complications, time to radiographic union and current clinical state including Olerud and Molander scores were recorded (as a measure of ankle function). RESULTS: Nine of 31 patients had died by the time of follow-up. Mean preoperative and postoperative Olerud and Molander scores were 56 and 45, respectively. There were no postoperative wound complications. Twenty-nine of 31 patients returned to the same level of mobility as pre-injury. There were three peri-prosthetic fractures managed successfully with nail removal and replacement or plaster cast. There were two nail failures, both in patients who mobilised using only a stick, which were managed by nail removal. Ten of 31 patients were not followed up radiographically due to either infirmity or death. Thirteen of 21 followed up radiographically had evidence of union and 8/21 had none. None, however, had clinical evidence of fracture nonunion. CONCLUSION: The TTC nail can successfully be used to manage fragility fractures about the ankle in the elderly. Much like fractured neck of femur patients, who also have a high rate of mortality, this allows immediate mobilisation with minimal risk of wound complications. However, careful assessment must be made of each patient's mobility, as there is a significant incidence of device failure in the more active patient.

The emergent assessment of supracondylar fractures of the paediatric humerus.

Supracondylar fractures of the distal humerus are a common and serious paediatric injury, often accompanied by neurovascular compromise. Accurate neurovascular evaluation of the injured limb is essential in order to guide emergent treatment. To assess whether trainees are proficient in the assessment and management of supracondylar fractures, performance was audited against objective standards drawn from the literature.

The cadaveric anatomy of the distal radius: implications for the use of volar plates.

INTRODUCTION: Fractures of the distal radius are common upper limb injuries, representing a substantial proportion of the trauma workload in orthopaedic units. With ever increasing advancements in implant technology, operative intervention is becoming more frequent. As growing numbers of surgeons are performing operative fixation of distal radial fractures, an accurate understanding of the relevant surgical anatomy is paramount. The flexor carpi radialis (FCR) tendon forms the cornerstone of the Henry approach to the volar cortex of the distal radius. A number of key neurovascular structures around the wrist are potentially at risk during this approach, especially when the FCR is mobilised and placed under retractors. METHODS: In order to clarify the safe margins of the FCR approach, ten fresh frozen human cadaver limbs were dissected. The location of the radial artery, the median nerve, the palmar cutaneous branch of the median nerve and the superficial branch nerve were measured with respect to the FCR tendon. Measurements were taken on a centre-to-centre basis in the coronal plane at the watershed level. In addition, the distances between the tendons of brachioradialis, abductor pollicis longus and flexor pollicis longus, and the radial artery and median nerve were measured to create a complete picture of the anatomy of the FCR approach to the distal radius. RESULTS: The structure most at risk was the palmar cutaneous branch of the median nerve. It was located on average 3.4mm from the FCR tendon. The radial artery and the main trunk of the median nerve were located 7.8mm and 8.9mm from the tendon. The superficial branch of the radial nerve was 24.4mm from the FCR tendon and 11.1mm from the brachioradialis tendon. CONCLUSIONS: Operative intervention is not without complication. We believe a more accurate understanding of the surgical anatomy is key to the prevention of neurovascular damage arising from the surgical management of distal radial fractures.

Intramedullary nailing for pathological fractures of the ulna.

Pathological lesions of long bones increase the morbidity of many common cancers. The orthopedic management of metastatic skeletal lesions can be challenging. The ultimate aim is to provide patients with a painless, functional limb. We present a report of two cases were a novel minimally invasive long bone nailing technique has been utilized to achieve skeletal stability and alleviation of symptoms.

Upper limb deep vein thrombosis: a potentially fatal complication of a clavicle fracture.

We present a case a 48-year-old man who was diagnosed with an upper limb deep vein thrombosis post clavicle fracture. He was successfully investigated with a computed tomography (CT) venogram, thrombophilia was excluded, and he was subsequently treated with a 3-month course of anticoagulation. We illustrate this case with photographs and a three-dimensional colour reconstruction of a CT venogram to raise awareness of the condition. A suitable level of clinical suspicion should be maintained by the orthopaedic surgeon; delayed arm swelling with venous congestion following a clavicle fracture should be investigated with CT venography and thrombophilia should be excluded.

The volar anatomy of the distal radius--an MRI study of the FCR approach.

INTRODUCTION: Fractures of the distal radius are one the commonest orthopaedic injuries. Recent advances in implant technology have seen a dramatic rise in the number of fractures treated with volar locked plates, as they permit accurate peri-articular reconstruction. The surgical approach along the bed of flexor carpii radialis (FCR) tendon encounters a number of key soft tissue and neurovascular structures during the dissection to the fracture plane. The aim of this study was to describe the exact position of such structures involved (and hence at risk) during the FCR approach. METHODS: 100 adult MRI scans were reviewed. The relationships between the brachioradialis tendon (BR), flexor carpi radialis (FCR) tendon, flexor pollicis longus (FPL) tendon, median nerve (MN) and radial artery (RA) were measured. RESULTS: The male to female ratio was 35:65. Average age was 39. FCR tendon was 7.4 mm (SD 1.46) from the RA and 7.01 mm (SD 2.37) from the MN. The distance between BR and RA was significantly different between male and female (5.06 mm vs. 4.1 mm, p=0.034). CONCLUSION: This study highlights the precise nature of the surgical anatomy involved in dissection to the fracture site. Vigilance is needed during the initial steps of the FCR-bed approach to avoid damage to the radial artery and median nerve which lie in close proximity. If the approach is extended to include a brachioradialis tenotomy, we suggest this should be made under direct vision, given its relationship with the radial artery.

Pamamycin: a new antibiotic and stimulator of aerial mycelia formation.

Pamamycin is a new antibiotic isolated from Streptomyces alboniger ATCC 12461. The antibiotic is active in vitro against Gram-positive bacteria, Neurospora, and Mycobacteria. The compound also acts as a streptomycete differentiation effector. It stimulates aerial mycelia formation in the producing organism. The new antibiotic of elemental composition C36H63NO7 is completely different from puromycin, also produced by this strain. The present communication deals with the isolation, properties, and preliminary characterization of pamamycin.

Simultaneous loss of multiple differentiated functions in aerial mycelium-negative isolates of streptomycetes.

Germination and outgrowth of spores of Streptomyces alboniger, Streptomyces scabies, and Streptomyces violaceus-ruber in the presence of intercalating dyes resulted in a high frequency (2 to 20%) of occurrence of aerial mycelium-negative (Amy-) isolates. Coincident with the appearance of the Amy- trait was the loss of several differentiated functions, including the characteristic pigments and earthy odor of the wild types. All S. alboniger, 27% of S. scabies, and 39% of the S. violaceus-ruber Amy- isolates were arginine auxotrophs. The missing enzyme step was identified as argininosuccinate synthetase by using a sensitive microassay for estimation of enzyme activity. The remainder of the S. scabies and S. violaceus-ruber isolates were prototrophs. In addition, S. alboniger Amy- isolates failed to produce or respond to the stimulator of aerial mycelium formation isolated from the wild type. The Amy- isolates did not revert to either Amy+ of Arg+. The lack of any detectable reversion, coupled with the high frequency of curing, supports the idea that a deletion of genetic material, possibly a plasmid, has occurred.

Control of differentiation in streptomycetes: involvement of extrachromosomal deoxyribonucleic acid and glucose repression in aerial mycelia development.

When Streptomyces alboniger spores were grown in Hickey-Tresner broth containing 5 muM ethidium bromide, a high frequency of permanently cured aerial mycelia-negative (am-) colonies was recovered. The appearance an am- colonies was time dependent: a very low frequency (0.3%) at zero time, a maximum (9 to 21%) after 2 to 5 days of growth, and a decline again to low frequencies later in the growth cycle. On agar, cured am- colonies of S. alboniger still produced puromycin. The development of aerial mycelia in S. alboniger, S. scabies, and S. coelicolor was also sensitive to glucose repression. Colonies grown on Hickey-Tresner agar containing 2% glucose remained phenotypically am- throughout the observation period. Adenine (2.5 mM or greater), and to a lesser extent adenosine and guanosine, specifically reversed the repression. The accumulation of undissociated organic acids appears to be involved in glucose repression of aerial mycelia formation. However, this does not appear to be the case with puromycin production in S. alboniger; glucose repression was observed over the pH range 5.0 to 7.5.