Arthrographic description of the canine carpal joint cavities and its recesses.

Joint effusion is diagnostically important. The canine carpal joint effusion, which is sometimes difficult to detect clinically, has received less attention in diagnostic ultrasound (US) studies. The aim of the present study was to provide a description of the morphological appearance of the canine carpal joint cavities and recesses using US, radiography, helical computed tomography (CT) and three-dimensional volume rendering technique (3D-VRT) images and to prove the applicability of musculoskeletal US for the detection of artificial carpal joint effusion in dogs. The understanding of the characteristics of these structures in normal patients is essential in the diagnosis. Twenty-eight clinically and radiologically unremarkable canine carpal cadavers of different breeds were examined, representative images were selected and anatomical structures were labelled. The canine carpal joint cavities and in particular its recesses had a complex appearance with a basic structure found in all dogs: Antebrachiocarpal joint: dorsoproximal antebrachiocarpal recess, dorsodistal antebrachiocarpal recess, medial antebrachiocarpal recess, lateral antebrachiocarpal recess and five palmar antebrachiocarpal recesses. Middle carpal joint: two dorsal middle carpal recesses, medial common middle carpal and carpometacarpal recess, lateral common middle carpal and carpometacarpal recess, four palmar middle carpal recesses. The carpometacarpal joint had dorsal and palmar funnel-shaped and irregular, finely tubular extensions, the most prominent ran dorsal to metacarpal III, the maximum distal end represented the proximal metacarpal diaphysis. All recesses presented ultrasonographically as a generalized anechogenic to hypoechoic filled continuation of the articular capsule with an indistinct peripheral hypoechogenic to isoechogenic fine capsule, the synovial-connective tissue interface was difficult to identify. The novel results of this study provide the first morphological description of the ultrasonographic, radiographic and computed tomographic arthrographic appearance of the canine carpal joint cavities and recesses with different injection volumes. The canine carpal joint cavities and in particular its recesses had a complex appearance with a basic structure found in all dogs. The applicability of musculoskeletal US to visualize an artificial carpal effusion has been demonstrated. The results of this study, and in particular US, give the practitioner an advantage in visualizing joint effusion and assist in the decision to perform arthrocentesis.

Novel arthrocentesis approaches to the carpal joint of the Dromedary Camel (Camelus dromedarius).

The knowledge gap regarding the topography and anatomy of the dromedary's carpal joint must be bridged to improve diagnostic and treatment procedures such as ultrasonography, arthrocentesis, and arthroscopy. Thirty-five distal forelimbs were harvested from 21 dromedaries and studied through gross dissection, casting, ultrasonography, and computerized tomography. Representative three-dimensional models of the joint cavities, recesses, and pouches were obtained using various casting agents. The safety and feasibility of different arthrocentesis approaches were evaluated. This study provides a detailed description of dorsally located joint recesses and palmarly located joint pouches. The dorsomedial and dorsolateral approach is recommended for arthroscopy and arthrocentesis of the radiocarpal and intercarpal joint when the carpus is flexed. However, caution must be exercised during these approaches to prevent needle injury to the articulating cartilage. Caution is necessary to prevent the formation of inadvertent communication between the dorsally located tendon sheaths and joint cavities. Arthrocentesis via the lateral approach to the lateropalmar pouch is the most favourable approach for the radiocarpal joint. A subtendinous synovial bursa was found between the lateropalmar pouch of the radiocarpal joint and the extensor carpi ulnaris muscle. The subtendinous synovial bursa must be considered during the lateral arthrocentesis approach. The palmar approach is not recommended for arthrocentesis due to the high risk of injury to nerves, veins, and arteries located palmarly.

Comparison between high-field 3 Tesla MRI and computed tomography with and without arthrography for visualization of canine carpal ligaments: A cadaveric study.

OBJECTIVE: To compare the quality of visualization of canine carpal ligaments by using computed tomography (CT), MRI, CT arthrography (CTA), and magnetic resonance arthrography (MRA). STUDY DESIGN: Prospective descriptive study. STUDY POPULATION: Cadavers from dogs weighing more than 20 kg. METHODS: A 16-slice CT scanner and a 3 Tesla MRI were used for the investigation. A dilute contrast medium was injected into the middle carpal and radiocarpal joints under fluoroscopic control, and CTA and MRA images were acquired. To evaluate the difference between imaging modalities, 3 observers graded carpal ligaments of clinical interest using a scale from 0 to 4 for their quality of visualization. Data were analyzed by using a random-effect ordinal logistic regression with Bonferroni adjustment. The interobserver agreement was calculated by using the weighted Cohen's κ. RESULTS: Normal carpal joints (n = 9) were investigated. Magnetic resonance arthrography improved visualization of the majority of carpal ligaments compared with MRI (P < .05) and offered the best visualization overall. Magnetic resonance imaging and MRA offered better visualization compared with both CT and CTA (P < .05). There was no difference between CT and CTA. Interobserver agreement was discrete (0.2 < κ ≤ 0.4) for all observers. CONCLUSION: Arthrography improved the capabilities of MRI but not of CT for visualization of the canine carpal ligaments. Magnetic resonance arthrography was particularly useful for evaluation of the stabilizers of the antebrachiocarpal joint. CLINICAL SIGNIFICANCE: 3 Tesla MRA and MRI allow excellent visualization of the ligamentous morphology and may be helpful in the diagnostic process of carpal sprains in dogs.

Palmar arthroscopic approach and intra-articular anatomy of the bovine carpal joints.

OBJECTIVE: To describe the palmar arthroscopic approaches to the bovine carpus and document the visible intra-articular structures in each approach. STUDY DESIGN: Ex vivo study. SAMPLE POPULATION: Thirty fresh cadaveric bovine forelimbs. METHODS: Computed tomography (CT) and gross dissection were performed on 4 carpi. Latex models were produced from 6 carpi to define the gross anatomy and arthroscopic portals to the palmar carpal pouches. Ultrasonography and arthroscopy were performed on 20 carpi to document visualization of the local anatomy. RESULTS: A single palmar pouch was present on both sides of each joint on gross dissection and evaluation of latex models. The relationship between pouches and palmar structures was observed by CT. Small anechoic areas identified on ultrasonography increased after joint distension. Palmar arthroscopy of the antebrachiocarpal joint enabled visualization of the palmar surfaces of radial, intermediate, and ulnar carpal bones; distal radius; ulnar styloid process; palmar radiocarpal ligament; and articulation of accessory and ulnar carpal bones. Palmar arthroscopy of the middle carpal joint enabled inspection of the palmar aspects of ulnar, intermediate, radial, fused second and third and fourth carpal bones, palmar carpometacarpal ligament, and the short lateral collateral ligament. Palmar aspects of the fourth and fifth metacarpal bones were explored through the palmarolateral approach to the middle carpal joint. Instrument portals for each pouch were created under arthroscopic guidance. CONCLUSION: Palmar arthroscopy of the adult bovine carpus enabled visualization of the clinically relevant palmar intra-articular structures. CLINICAL SIGNIFICANCE: Palmar carpal arthroscopy should be considered as an adjunct to dorsal approach for the diagnosis and treatment of bovine carpal diseases.

An Anthropometric Assessment of the Proximal Hamate Autograft for Scaphoid Proximal Pole Reconstruction.

PURPOSE: Fragmentation of the scaphoid proximal pole secondary to avascular necrosis presents a difficult reconstructive problem. This anthropometric study assesses the utility of the ipsilateral proximal hamate for complete osteochondral scaphoid proximal pole reconstruction. METHODS: Twenty-nine cadaveric specimens underwent computed tomography scanning and 3-dimensional reconstruction of the carpus and distal radius. Scaphoid height was measured and a third of its height was used to simulate resection of the proximal scaphoid pole and extent of hamate autograft required. The proximal scaphoid and hamate were divided into 6 sections, and compared using an iterative point-to-point distance algorithm. Average distance between the scaphoid and the hamate surfaces was determined. An interbone algorithm was used to assess radioscaphoid joint congruency and articular contact surface of the native scaphoid compared with the scaphoid reconstructed with hamate autograft. RESULTS: The mean height of scaphoid proximal pole excision and proximal hamate autograft height was 9.3 mm. Comparing the morphology of the native scaphoid and hamate autografts, the absolute distances were the largest in the volar radioscaphoid, dorsal radioscaphoid, and dorsal scaphocapitate segments. Without osteotomy, the hamate autograft may cause impaction in the dorsal-radial aspect of the distal radius. The hamate autograft also shifted the articular contact point of the radioscaphoid joint toward the dorsal-radial position. Nine hamate autografts were classified as poor-fitting. Poor-fitting specimens had a greater radial styloid to distal radioulnar joint distance. These specimens also had wider hamates and scaphoids in the radial-ulnar dimension and wider scaphoids in the volar-dorsal dimension. Lunate type did not correspond to anthropometric fit. CONCLUSIONS: The proximal hamate osteochondral graft was poor fitting in 31% of cases (9 of 29 specimens). Wrists with radial-ulnar hamate width less than 10 mm, radial-ulnar scaphoid width less than 10 mm, and volar-dorsal scaphoid width less than 16 mm demonstrate better anthropometric fit. CLINICAL RELEVANCE: This study provides an anthropometric assessment of the recently described proximal hamate autograft, a new bone graft option for proximal scaphoid pole reconstruction.

A composite 3D printed model of the midcarpal joint.

Three-dimensional (3D) printing has recently been developed as a resource for teaching human anatomy through the accurate reproduction of anatomical specimens. Using a composite 3D printed model with the incorporation of metal and magnets, we were able to demonstrate and analyse movements at the midcarpal joint during the 'dart thrower's motion', which is an important motion in daily activities involving the use of the hand. The hand component with the distal row of carpal bones was subjected to flexion and extension at the midcarpal joint and observed for simultaneous abduction/adduction. Notable adduction was observed in the flexed position as compared to the extended position. Moreover, while the primary movements at the midcarpal joint were taking place in the medial part of the joint, the lateral part of the joint (which is ellipsoid) served to accommodate the arc of movement. We suggest that such composite 3D printed models are useful teaching tools for enhancing the understanding of complex joint movements.

Are adult carpal angle measurements applicable to the pediatric population in the trauma setting?

OBJECTIVE: The aim of this study is to assess the applicability of standard adult carpal angle measurements, specifically the scapholunate and capitolunate angles, in the assessment of the pediatric wrist. MATERIALS AND METHODS: The study cohort comprised male and female children who underwent a wrist radiograph for the evaluation of suspected wrist injuries following trauma. A gender- and indication-matched adult cohort was also assessed. To ensure an accurate carpal angle measurement, only individuals with a sufficiently ossified carpus and an adequately positioned lateral wrist radiograph were included. RESULTS: Carpal angle measurements were performed on the lateral wrist radiographs of 256 individuals between the ages of 5 and 17 years (mean 11.2 years, SD ± 2.5 years) and 256 individuals between the ages of 18 and 40 years (mean 28.8 years, SD ± 6.2 years). The mean pediatric scapholunate angle was 47° (SD ± 8) and the mean pediatric capitolunate angle was 11° (SD ± 7). The mean adult scapholunate and capitolunate angles were 48° (SD ± 8°) and 10° (SD ± 6°) respectively. No statistically significant difference was observed between the scapholunate or capitolunate angle measurements in the two groups (p = 0.26 and p = 0.36). CONCLUSION: The study data supports the applicability of standard adult carpal angle values to the pediatric population provided the carpus is sufficiently ossified.

Reduction of the A-Frame Angle of Incline does not Change the Maximum Carpal Joint Extension Angle in Agility Dogs Entering the A-Frame.

OBJECTIVE: This article aims to investigate the effect of a decrease in the A-frame angle of incline on the highest carpal extension angle in agility dogs. METHODS: Kinematic gait analysis (two-dimensional) measuring carpal extension was performed on 40 dogs entering the A-frame at 3 angles of incline: 40° (standard), 35° and 30°. The highest carpal extension angle from three trials at each incline was examined for a significant effect of A-frame angle with height, body weight and velocity included as covariates. RESULTS: There was no significant effect of A-frame angle on the highest carpal joint extension angle for the first or second limb. The adjusted mean carpal extension angle for the first limb at 40° was 64° [95% confidence interval (CI), 60-68), at 35° was 61° (95% CI, 57-65) and at 30° was 62° (95% CI, 59-65). The raw mean carpal extension angle for all dogs across all A-frame angles for the first limb was 62° (95% CI, 60-64) and the second limb was 61° (95% CI, 59-63). CLINICAL SIGNIFICANCE: Decreasing the A-frame angle of incline from 40° to 30° did not result in reduced carpal extension angles. The failure to find a difference and the narrow CI of the carpal angles may indicate that the physiologic limits of carpal extension were reached at all A-frame angles.

Management of Pisotriquetral Instability.

Pisotriquetral instability is an often-overlooked condition that can lead to ulnar-sided wrist pain and dysfunction. Various case series and biomechanical studies have been published regarding the diagnosis and treatment of this condition. We review current methods for examining, diagnosing, and treating pisotriquetral instability.

Incidence and anatomical distribution of hand tumours: a Singapore study.

INTRODUCTION: Hand tumours are frequently encountered in clinical practice. A list of differential diagnoses of the most common hand tumours based on anatomical location would be helpful for clinicians. We aimed to determine the anatomical distribution of hand tumours seen at a hand surgery practice in Singapore. METHODS: The medical records of 50 men and 65 women (mean age 41.7 [range 17-74] years) who underwent excision of hand tumours between 1 June 2010 and 31 December 2012 were reviewed. The histological diagnoses and anatomical locations of the tumours were analysed. The locations were divided into three main groups: (a) distal to the metacarpophalangeal joints (MCPJs); (b) between the MCPJs and carpometacarpal joints (CMCJs); and (c) between the CMCJs and the radiocarpal joint (RCJ). RESULTS: Overall, the most common tumours excised from the hand were ganglions (n = 66/116, 56.9%) and giant cell tumours of the tendon sheath (GCTTSs; n = 11/116, 9.5%). However, distal to the MCPJs, GCTTSs (n = 11/39, 28.2%) were more common than ganglions (n = 7/39, 17.9%). Most of the ganglions (n = 59/66, 89.4%) arose from between the CMCJs and RCJ. CONCLUSION: Most hand tumours were benign. Ganglions were the most common tumours between the CMCJs and RCJ, while GCTTSs were the most common tumours distal to the MCPJs.

Role of muscles in the stabilization of ligament-deficient wrists.

This article reviews the results of a series of cadaver investigations aimed at clarifying the role of muscles in the stabilization of ligament-deficient wrists. According to these studies, isometric contraction of some forearm muscles induces midcarpal (MC) supination (ie, the abductor pollicis longus, extensor carpi radialis longus, and flexor carpi ulnaris), whereas other muscles induce MC pronation (ie, the extensor carpi ulnaris). Because MC supination implies tightening of the volar scaphoid-distal row ligaments, the MC supination muscles are likely to prevent scaphoid collapse of wrists with scapholunate ligament insufficiency. MC pronator muscles, by contrast, would be beneficial in stabilizing wrists with ulnar-sided ligament deficiencies owing to their ability to tighten the triquetrum-distal row ligaments. Should these laboratory findings be validated by additional clinical research, proprioceptive reeducation of selected muscles could become an important tool for the treatment of dynamic carpal instabilities.

Dorsal Arthroscopic Approach and Intra-Articular Anatomy of the Bovine Antebrachiocarpal and Middle Carpal Joints.

OBJECTIVE: To determine arthroscopic approaches to the dorsal synovial compartments of the antebrachiocarpal and middle carpal joints in adult cattle, and to describe the arthroscopic intra-articular anatomy from each approach. STUDY DESIGN: Ex vivo study. ANIMALS: Six fresh adult bovine cadavers. METHODS: Two carpi were injected with latex and dissected to determine the ideal location for arthroscopic portals. Arthroscopy of the antebrachiocarpal and middle carpal joints of 10 carpi was then performed. The dorsolateral approach was made between the extensor carpi radialis and common digital extensor tendons. The dorsomedial approach was made medial to the extensor carpi radialis tendon, midway between the distal radius and proximal row of carpal bones (antebrachiocarpal joint) and midway between the two rows of carpal bones (middle carpal joint), with the joint in flexion. RESULTS: Arthroscopy of the antebrachiocarpal joint allowed visualization of the distal radius, proximal aspect of the radial, intermediate and ulnar carpal bones, and a palmar ligament located between the radius and the intermediate carpal bone. The approach to the middle carpal joint allowed visualization of the distal aspect of the radial, intermediate, and ulnar carpal bones, the proximal aspect of the fourth and fused second and third carpal bones and an interosseous ligament. The most lateral articular structures (lateral glenoid cavity of the distal radius, ulnar carpal and fourth carpal bones) were difficult to assess. CONCLUSION: Dorsal approaches to the antebrachiocarpal and middle carpal joints allowed visualization of most intra-articular dorsal structures in adult cattle.

The carpal joint of the donkey (Equus asinus): morphological investigation / Articulación del carpo del asno (Equus asinus): investigación morfológica

The current study has been achieved to be an essential resource for all veterinary practitioners that deal with the anatomy of the carpal joint of the donkey. Ten adult donkeys of both sexes were used in the current study. The topographical approach to the carpal joint was investigated in this study. Radiography and computed tomography (CT) of the carpus delineated the articulations of the carpal joint: radiocarpal, intercarpal, and carpometacarpal. The carpal ligaments were well delineated and the carpal canal was demonstrated with its content such as superficial digital flexor tendon (SDFT) and deep digital flexor tendon (DDFT). The contrast radiography visualized that the radiocarpal joint outpouched proximal to the accessory carpal bone by large palmarolateral pouch and small palmaromedial pouch, however the intercarpal joint outpouched distal to the accessory carpal bone by two small palmarolateral and palmaromedial pouches. The carpometacarpal joint showed medial and lateral palmarodistal outpouchings in distal direction between the corresponding 2nd and 4th metacarpal bones and the 3rd metacarpal bone. Scanning electron microscopy (SEM) displayed two types of synoviocytes macrophages type A cells and fibroblast like type B cells at the cellular lining of the synovial membrane of the joint capsule.

Este estudio constituye un recurso esencial para todos los veterinarios que se ocupan de la anatomía de la articulación del carpo del asno. Fueron utilizados diez asnos adultos, de ambos sexos. Se analizó la articulación del carpo desde un enfoque topográfico. Se realizaron estudios por radiografía y tomografía computarizada para identificar las articulaciones del carpo en su conjunto: radiocarpiana, intercarpiana y carpometacarpiana. Los ligamentos del carpo se encontraron bien delineados y en el canal carpiano se identificó su contenido, como el tendón del flexor digital superficial y el tendón del flexor digital profundo. La radiografía de contraste permitió visualizar que la articulación radiocarpiana se articula proximalmente con el hueso accesorio del carpo a través una larga evaginación palmarolateral y una pequeña evaginación palmaromedial; sin embargo, la articulación intercarpiana se relaciona distalmente con el hueso accesorio del carpo por medio de dos pequeñas evaginaciones, palmarolateral y palmaromedial. La articulación carpometacarpiana mostró evaginaciones palmarodistales, medial y lateral, en dirección distal entre los correspondiente 2 y 4 huesos metacarpianos y el 3 hueso metacarpiano. La microscopía electrónica de barrido muestra dos tipos de células: células A, correspondientes a sinoviocitos macrófagos y células B, correspondientes a fibroblastos, en el revestimiento celular de la membrana sinovial de la cápsula articular.

Carpal Ligament Anatomy and Biomechanics.

A fundamental understanding of the ligamentous anatomy of the wrist is critical for any physician attempting to treat carpal instability. The anatomy of the wrist is complex, not only because of the number of named structures and their geometry but also because of the inconsistencies in describing these ligaments. The complex anatomy of the wrist is described through a review of the carpal ligaments and their effect on normal carpal motion. Mastery of this topic facilitates the physician's understanding of the patterns of instability that are seen clinically.

Three-dimensional Analysis of the Attachment and Path of the Transverse Carpal Ligament.

PURPOSE: The purpose of this study was to describe and evaluate the detailed anatomic locations and areas of ligamentous attachments and paths of the transverse carpal ligament (TCL) on a three-dimensional (3-D) surface model. METHODS: Ten fresh-frozen cadaver wrists were used to dissect and identify the TCL. Their ligament attachments and whole bone surfaces were digitized three-dimensionally and their areas evaluated. The attachments of each ligament were represented in a model combining CT surfaces overlaid by a digitized 3-D surface, and were also visually depicted with a different color for each on 3-D images of the bones. RESULTS: The TCL was found to be composed of two or three discrete ligaments. Both the trapezium-hook of hamate ligament and the trapezium-pisiform ligament were identified in all ten specimens. The scaphoid-pisiform ligament was found in only two of the ten specimens. The average areas of the attachments of the TCL were 42.7 mm(2) on the trapezium, 30.0 mm(2) on the hook of hamate, 21.6 mm(2) on the pisiform, and 12.7 mm(2) on the scaphoid. CONCLUSIONS: The anatomic 3-D attachment sites of the TCL were visually shown qualitatively, and their areas quantified. This 3-D information offers further knowledge and understanding of the anatomy and biomechanics of the TCL. It could also help in the accurate assessment of radiographic images and treatment of various wrist injuries and diseases when performing such procedures as carpal tunnel release, Guyon's canal release, trapeziectomy, hook of hamate excision, or arthroscopy.

Elliptical morphology of the carpal tunnel cross section

Although the carpal tunnel is known for its anatomical constituents, its morphology is not well recognized. The aim of this study was to investigate the morphometric properties of the carpal tunnel and its surrounding structures. Magnetic resonance and cross-sectional images of the distal carpal tunnel were collected from eight cadaveric hands. Morphological analyses were performed for the cross sections of the carpal tunnel, interior carpus boundary, and exterior carpus boundary. The specimens had a carpal arch width and height of 23.9 ± 2.9 mm and 2.2 ± 0.9 mm, respectively. The carpal tunnel, interior carpus boundary, and exterior carpus boundary had perimeters of 54.8 ± 4.5 mm, 68.5 ± 7.0 mm, and 130.6 ± 11.8 mm, respectively, and areas of 183.5 ± 30.1 mm2, 240.7 ± 40.2 mm2, and 1002.3 ± 183.7 mm2, respectively. The cross sections were characterized by elliptical fitting with aspect ratios of 1.96 ± 0.15, 1.96 ± 0.19, and 1.76 ± 0.19 for the carpal tunnel, interior carpus boundary, and exterior carpus boundary, respectively. The major axis of the boundaries increased in pronation angle, relative to the hamate-trapezium axis, for the exterior carpus (6.0 ± 3.0º), interior carpus (8.2 ± 3.2º), and carpal tunnel (15.9 ± 2.2º). This study advances our understanding of the structural anatomy of the carpal tunnel, and the morphological information is valuable in the identification of structural abnormality, assistance of surgical planning, and evaluation of treatment of effects

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Surgical technique: hemi-extensor carpi radialis brevis tenodesis for stabilizing the midcarpal joint in Ehlers-Danlos syndrome.

Patients with the hypermobility type of Ehlers-Danlos (EDS-HT) often complain of wrist pain, usually originating from subluxations. As a result of the laxity, wrist function in these patients can be highly limited. This paper presents a surgical technique that stabilizes the lunocapitate joint with the use of an extensor carpi radialis brevis strip. Five patients with confirmed EDS-HT were treated with an extensor carpi radialis brevis tenodesis for their midcarpal instability. Two patients presented with complications following surgery, one major and one minor. This paper presents a potentially satisfactory surgical solution to recurrent midcarpal instability in EDS-HT patients and demonstrates that the use of an autologous tendon might be feasible in spite of a background of abnormal collagen metabolism.

Measurements of normal joint angles by goniometry in calves.

OBJECTIVE: The aim of this study was to establish normal reference values of the forelimb and hindlimb joint angles in normal Holstein calves. METHODS: Thirty clinically normal Holstein calves that were free of any detectable musculoskeletal abnormalities were included in the study. A standard transparent plastic goniometer was used to measure maximum flexion, maximum extension, and range-of-motion of the shoulder, elbow, carpal, hip, stifle, and tarsal joints. The goniometric measurements were done on awake calves that were positioned in lateral recumbency. The goniometric values were measured and recorded by two independent investigators. RESULTS: As a result of the study it was concluded that goniometric values obtained from awake calves in lateral recumbency were found to be highly consistent and accurate between investigators (p <0.05). CLINICAL SIGNIFICANCE: The data of this study acquired objective and useful information on the normal forelimb and hindlimb joint angles in normal Holstein calves. Further studies can be done to predict detailed goniometric values from different diseases and compare them.

Dynamic motion analysis of dart throwers motion visualized through computerized tomography and calculation of the axis of rotation.

We used a dynamic three-dimensional (3D) mapping method to model the wrist in dynamic unrestricted dart throwers motion in three men and four women. With the aid of precision landmark identification, a 3D coordinate system was applied to the distal radius and the movement of the carpus was described. Subsequently, with dynamic 3D reconstructions and freedom to position the camera viewpoint anywhere in space, we observed the motion pathways of all carpal bones in dart throwers motion and calculated its axis of rotation. This was calculated to lie in 27° of anteversion from the coronal plane and 44° of varus angulation relative to the transverse plane. This technique is a safe and a feasible carpal imaging method to gain key information for decision making in future hand surgical and rehabilitative practices.

Use of bovine carpal joints as a training model for cruciate ligament repair.

BACKGROUND: Currently, there is a lack of cheap and effective training models to allow orthopaedic surgery trainees to learn the basics of anterior cruciate ligament reconstruction. The aim of this paper was to investigate the viability of using various animal joints as models for the training of anterior cruciate ligament reconstruction. METHOD: Equine stifles, bovine stifles and carpal joints, sheep stifles and porcine stifles, were sourced from a local abattoir. Each joint was assessed for the following criteria: suitable tendons for harvesting, ease of arthroscopy access, adequacy of arthroscopy view and suitable joint surfaces. Tendon harvesting, preparation, joint arthroscopy and tendon tunnelling were performed on the most suitable joint. RESULTS: Equine, bovine, sheep and porcine stifles were found to be unsuitable. The bovine carpal joint was similar to a human wrist joint with two rows of carpal bones and fused metacarpal bones, but with deeper flexion - similar to a human knee joint. The distal joint space was found to provide a greater range of flexion and space than the narrower proximal joint space. The joint capsule provided sufficient integrity during saline irrigation to allow adequate visualization of joint structures. Tendons surrounding the joint were found to be of similar diameter to human hamstring tendons and easily accessible. Tendon tunnelling was successfully performed in a manner similar to human anterior cruciate ligament repair. CONCLUSION: The use of bovine carpal joints is a cost-effective, safe and easily reproducible model for education on basic anterior cruciate ligament repair skills and technique prior to patient contact.