Surgery (St Vincent's) - Research Publications

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    Scaphoid, lunate and capitate kinematics in the normal and ligament deficient wrist: A bi-plane X-ray fluoroscopy study
    Zhang, X ; Tham, S ; Ek, ET ; Mccombe, D ; Ackland, DC (ELSEVIER SCI LTD, 2023-09)
    The ligamentous structures of the wrist stabilise and constrain the interactions of the carpal bones during active wrist motion; however, the three-dimensional translations and rotations of the scaphoid, lunate and capitate in the normal and ligament deficient wrist during planar and oblique wrist motions remain poorly understood. This study employed a computer-controlled simulator to replicate physiological wrist motion by dynamic muscle force application, while carpal kinematics were simultaneously measured using bi-plane x-ray fluoroscopy. The aim was to quantify carpal kinematics in the native wrist and after sequential sectioning of the scapholunate interosseous ligament (SLIL) and secondary scapholunate ligament structures. Seven fresh-frozen cadaveric wrist specimens were harvested, and cycles of flexion-extension, radial-ulnar deviation and dart-thrower's motion were simulated. The results showed significant rotational and translational changes to these carpal bones in all stages of disruptions to the supporting ligaments (p < 0.05). Specifically, following the disruption of the dorsal SLIL (Stage II), the scaphoid became significantly more flexed, ulnarly deviated, and pronated relative to the radius, whereas the lunate became more extended, supinated and volarly translated (p < 0.05). Sectioning of the dorsal intercarpal (DIC), dorsal radiocarpal (DRC), and scaphotrapeziotrapezoid (STT) ligaments (Stage IV) caused the scaphoid to collapse further into flexion, ulnar deviation, and pronation. These findings highlight the importance of all the ligamentous attachments that relate to the stability of the scapholunate joint, but more importantly, the dorsal SLIL in maintaining scapholunate stability, and the preservation of the attachments of the DIC and DRC ligaments during dorsal surgical approaches. The findings will be useful in diagnosing wrist pathology and in surgical planning.
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    The use of vascularised bone capping to prevent and treat amputation stump spiking in the paediatric population
    Murphy, AD ; Atkins, SE ; Thomas, DJ ; McCombe, D ; Coombs, CJ (WILEY, 2017-09)
    BACKGROUND: Overgrowth of the stump skeleton is a major complication seen in children after an amputation. In advanced cases, perforation of the bone spike through the skin can occur. Many surgical treatments have been employed to treat and prevent this, with best results seen when non-vascularised osteo-chondral bone grafts are placed to try to mimic a trans-articular amputation. We reviewed our outcomes using vascularized bone flaps to prevent and treat spiking. PATIENTS AND METHODS: Between 2000 and 2016 we carried out six vascularised osteo-cartilaginous bone capping procedures. Five patients underwent the procedure as an adjunct to primary amputation and in a single patient it was used to treat established bone spiking. Trauma accounted for three cases, with the other three being tumour, vascular malformation and ischemia. Three patients had pedicled bone flaps placed on the amputation stump and three underwent free tissue transfer (free calcaneus, free scapular angle, and free proximal tibia). Five cases involved lower limb amputations, with one in the upper limb. RESULTS: One patient had an early post-operative complication in the form of partial skin flap necrosis that required debridement and skin grafting. All bone flaps survived. Mean follow-up was 6.5 years. All patients had bony union with no development of stump spiking. Two patients required further procedures unrelated to the bone flaps. CONCLUSION: Vascularised bone flaps to cap amputation stumps may be a safe and effective method of preventing and treating long-bone stump spiking following amputation in children.
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    Dual-energy contrast-enhanced CT to evaluate scaphoid osteonecrosis with surgical correlation
    Pianta, M ; McCombe, D ; Slavin, J ; Hendry, S ; Perera, W (WILEY, 2019-02)
    To evaluate the validity of contrast enhanced dual energy CT using a lung perfusion algorithm in assessing for post-traumatic scaphoid proximal pole avascular necrosis. From Aug 2013 to Aug 2016, 18 patients (19 wrists, 16 males, 2 females, mean age 28 years) were assessed as high-risk for proximal pole scaphoid avascular necrosis by a single surgeon following a scaphoid fracture and were referred for contrast-enhanced dual energy CT. 8 wrists had specimens sent for correlative histological analysis and 11 were correlated with operative notes. Eight surgical specimens were sent to histology and showed a 100% correlation (8/8) with the DECT findings. The remaining 11 wrists that did not have a specimen sent had in-surgery findings that also correlated with DECT. A single case was discrepant (1/11) due to presence of an intra-osseous ganglion, which was reported as osteonecrosis on CT, but considered viable at surgery. No case was called viable on CT that proved to be necrotic at either surgery or histologically. Contrast-enhanced dual energy CT using a perfusion algorithm is an innovative and promising method in evaluating viability of the post-trauma proximal pole of scaphoid.
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    Ulnar-sided wrist pain: A prospective analysis of diagnostic clinical tests
    Yang, OO ; McCombe, DB ; Keating, C ; Maloney, PP ; Berger, AC ; Tham, SKY (WILEY, 2021-10)
    BACKGROUND: Identifying the cause of pain on the ulnar side of the wrist can be challenging. The outcome and recovery following surgery can be unpredictable. The aim of this study was to document and analyse the clinical tests used to evaluate the cause of ulnar-sided wrist pain and determine their diagnostic relevance. METHODS: This is a prospective evaluation of 110 patients who presented with pain on the ulnar side of the wrist. The clinical evaluation and results from radiological investigations were documented and analysed. RESULTS: There were 17 different diagnoses. Eighty-five percent of the diagnoses were triangular fibrocartilage complex (TFCC) injuries, ulnocarpal abutment syndrome (UCAS), pisotriquetral arthritis (PTA), triquetral fracture or non-union, distal radioulnar joint arthritis (DRUJ OA) and extensor carpi ulnaris (ECU) pathology. The ulnocarpal stress test and ulnar foveal sign were positive in several diagnoses. The ulnar foveal sign had a sensitivity and specificity of 89% and 48% for TFCC injuries, and 85% and 37% for UCAS, respectively. The sensitivity and specificity of pisotriquetral shear test for PTA was 100% and 92%, respectively. Patients with PTA or ECU pathology localised their pain better on the patient's pain localisation chart. CONCLUSION: Diagnosis of TFCC injuries, UCAS, DRUJ OA and ECU injuries are challenging as the clinical symptoms and signs for the four diagnoses were similar and required either magnetic resonance imaging or computed tomography for diagnostic confirmation after clinical examination. The ulnocarpal stress test and the ulnar foveal sign were not sufficiently specific.