Finger abduction as a novel function of the extensor digitorum brevis manus muscle.

A 25-year-old female presented with a chronic scapho-lunate ligament injury with development of carpal instability requiring reconstruction. During a standard dorsal longitudinal mid-line approach to the carpus, an extensor digitorum brevis manus (EDBM) muscle was found taking its origin from the dorsal wrist capsule overlying the lunate with innervation from the posterior interosseous nerve (PIN). Electrical stimulation of the muscle belly demonstrated abduction of the middle finger. The EDBM is a rare anatomical variant of the extensor compartment of the wrist and may be encountered during surgical approaches. Where possible these variant muscles should be carefully dissected off underlying structures, preserved and repaired at the conclusion of a procedure to ensure no perceived functional deficit to the patient. We present a case of a previously undescribed EDBM muscle function of pure finger abduction with no extension and a surgical technique of preserving its origin. We propose that the middle finger variant of the EDBM should be re-named the extensor digitorum brevis medius to reflect our findings.

Improved accuracy of CT based measurements for anterior prominence of acetabular prosthesis using a novel protocol based on anatomical landmarks.

BACKGROUND: Anterior hip pain after total hip replacement (THR) can be caused by iliopsoas impingement (IPI). Validation of CT measured cup version is well published; however quantification of the anterior cup prominence has not been validated. Therefore, we did an in vitro study aiming to: (1) assess the accuracy of the current method of measuring the prominence of the acetabular component using a dry bone model; (2) develop a CT protocol based on bony anatomical landmarks that improves the accuracy of these measurements. HYPOTHESIS: We hypothesise that utilising reproducible anatomical landmarks on the acetabulum will improve the accuracy of measurement of anterior prominence at the psoas valley. METHODS: A dry bone pelvic model was implanted with bilateral acetabular cups. The cup was manipulated into ten different combinations of inclination and version, and anterior prominence directly measured in relation to the acetabular rim. A CT scan was performed for each position. Anterior prominence was then measured by two radiologists, first using standard methods (axial slice at level of centre of femoral head) and then again using a novel protocol (based on the position of the psoas valley in relation to the inferior medial acetabular notch). RESULTS: Mean errors between direct measurement of anterior prominence and radiologist reported measurements using standard protocol were 6.94mm±5.24 (SD) (95%Confidence Interval: 3.25-4.27) and 5.14mm±3.07 (95%CI: 1.9-2.5) with a tendency towards overestimation of prominence. Using an anatomical landmark based protocol; mean error was reduced to 3.0mm±1.9 (95%CI: 1.16-1.53) and 4.3mm±4.3 (95%CI: 2.67-351) on the first attempt, and to 1.7mm±1.9 (95%CI: 1.15-1.52) and 2.1mm±1.4 (95%CI: 0.87-1.15) on the second attempt. Concordance correlation improved from 0.43 (95% CI: 0.19-0.68) and 0.59 (95% CI: 0.44-0.79) using the standard protocol, to 0.88 (95%CI: 0.61-0.91) and 0.9 (95%CI: 0.56-0.92) using the novel protocol. CONCLUSIONS: There is a difference in mean error and reliability between radiologically measured values for anterior prominence and values measured directly with present methods. The use of our novel protocol based on bony acetabular landmarks, significantly improves the accuracy of measurement. This protocol may improve reproducibility and the accuracy of this measurement and aid in the decision between tenotomy or revision of the acetabular component. LEVEL OF EVIDENCE: III, in vitro study comparing diagnostic tools.

The Influence of Obesity on Hip Pain, Function, and Satisfaction 10 Years Following Total Hip Arthroplasty.

BACKGROUND: The prevalence of obesity is rising, and increasing numbers of joint arthroplasty surgeries are being performed on obese patients. Concern exists that obesity increases surgical risk; however, its impact on function following total hip arthroplasty (THA) is inconsistently affirmed and less understood. A paucity exists in the literature pertaining long-term objective functional measures. Therefore, we investigated the impact of obesity on hip pain, function, and satisfaction 10 years following THA. METHODS: This single-center, prospective, observational study categorized consecutive THA patients according to their body mass index to nonobese (<30 kg/m2) and obese (≥30 kg/m2) groups. Preoperative assessment included a numerical pain rating and the Oxford Hip Score. These were repeated along with a 6-minute walk test and a Likert satisfaction scale at 3 months, 1, 5, and 10 years postoperatively. RESULTS: The series included 191 primary THA patients. No significant differences were found in hip pain or function between the obese and nonobese groups. Obese patients however had poorer walking capacity (P = .008), were more likely to use walking aids (P = .04), and were less satisfied (P = .04) at 10 years. CONCLUSION: THA confers significant long-term symptom resolution irrespective of obesity; however, despite undergoing surgery, obese patients can be counseled they may not be as satisfied as or achieve the same walking capacity as nonobese individuals.

Bennett fracture dislocation - review and management.

BACKGROUND: Bennett fracture dislocation is an intra-articular fracture of the base of the first metacarpal with resultant dislocation of the first carpometacarpal joint. The fracture is unstable, and with inadequate treatment leads to osteoarthritis, weakness and/or loss of function of the first carpometacarpal joint. OBJECTIVE: This article reviews the current literature on Bennett fracture and describes the clinical assessment and management of a Bennett fracture. DISCUSSION: Bennett fractures usually result from falling on an extended or abducted thumb or an impact onto a clenched fist. The patient presents with pain and loss of function of the first carpometacarpal joint. Management can involve closed reduction, with or without percutaneous Kirschner wire fixation, or open reduction and internal fixation, with adequate reduction and the maintenance of reduction being the key to a successful outcome. Due to the difficulty of management it is recommended that patients be referred to a specialist hand surgeon.

The application of molecular structural predictors of intestinal absorption to screening of compounds for transdermal penetration.

OBJECTIVES: The development of methods to predict the transport of molecules across biological membranes, without the need for time-consuming collection of experimental data, is a rapidly growing science. The use of structural characteristics of molecules has been investigated to predict the maximum transport rates of molecules across skin epidermal and intestinal membranes, known as maximum flux and maximum absorbable dose, respectively, although different approaches have been used. The aim of the present study was to determine whether the relationship between polar surface area and number of rotatable bonds of molecules and their permeability through intestinal membranes could be applied to the permeation of solutes through the epidermis following topical application. METHODS: We used a published dataset of human epidermal maximum flux values for 182 solutes and stepwise regression to determine relationships between structural predictors and maximum membrane transport rates. KEY FINDINGS: Results showed that diffusion processes occurring across intestinal and skin epidermal membranes cannot be estimated by the same solute molecular properties, as different combinations of partitioning and diffusion processes appear to be dominating in each type of membrane. The basis of these differences in terms of molecular weight dependence and the usefulness of polar surface area are discussed. CONCLUSIONS: Based on available literature, we concluded that transdermal penetration is poorly predicted by parameters derived from intestinal or Caco-2 model membranes. While this approach may be useful for small sets of structurally related compounds, it appears to have limited value for screening and selection of novel structures in the pharmaceutical industry.