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Biomedical subjects

I M Wright

Publications and source records attributed to I M Wright.

At least 37 records · Page 2Linked to original sources

Ligaments associated with joints.

This article contains a short introduction to the anatomy, physiology, and pathophysiology of ligaments associated with diarthrodial joints. Individual ligaments are discussed on a regional basis as forelimb, distal limb, and hindlimb. Emphasis is placed on the anatomy of the ligaments because this is the key to sound clinical application of their involvement in joint disease. There are few conditions of diarthrodial joints that do not involve their associated ligaments, and this role may be in causative, diagnostic, and therapeutic or convalescent considerations.

Animals↗

Surgical treatment of fractures of the tibial tuberosity in 6 adult horses.

This paper describes the clinical and radiological features, surgical techniques used and results obtained in 6 horses with fractures of the tibial tuberosity. The horses were presented between 24 h and 8 weeks following injury. In all 6 cases, the fragments were displaced proximocranially and in 2 of these, there was comminution. Four were treated by open reduction and internal fixation using an AO/ASIF narrow dynamic compression plate and in 2 cases the fragments were removed. All horses returned to full athletic function and remained sound in follow-up times of 17-36 months. Implant removal was necessary in 1 case.

Animals↗

Observations on the anatomy and pathology of the palmar intercarpal ligaments in the middle carpal joints of thoroughbred racehorses.

Ten carpi from juvenile Thoroughbred horses were dissected in detail to record the anatomy of the palmar intercarpal ligaments (PICLs). These were found not to be substantially attached to the palmar carpal ligament. The lateral PICL was sited at the convergence of the palmar aspects of the third, fourth, intermediate and ulnar carpal bones and aligned predominantly in a proximodistal direction. The medial PICL had a large origin distally on the lateral aspect of the radial carpal bone (Cr) and attached to third (C3) and second (C2) carpal bones with apparently separate fibre orientations. Fibres between Cr and C3 aligned obliquely from dorsoproximomedial to palmarodistolateral which corresponds to the direction of movement of Cr relative to C3 during carpal extension. Video recordings of arthroscopic evaluations of 67 middle carpal joints of juvenile Thoroughbred horses in race training were reviewed retrospectively and the osteochondral and ligamentous pathology visible in each recorded. Damage to the Cr-C3 part of the medial PICL was present in 47 (70%) joints and, in 6 joints, comprised complete rupture of this branch. A significant (P < 0.001) relationship was found between the presence of remodelling of the dorsodistal margin of Cr and the severity of ligament damage. It is considered that the orientation of fibres of the Cr-C3 branch of the MPICL is consistent with a putative role to alternate forces borne by Cr and C3 during axial loading of the limb and that the injuries of this structure seen in young racehorses may represent a fatigue-type pathology analogous to that seen concurrently in the related osteochondral tissues.

Animals↗

Biomechanical considerations in the treatment of navicular disease.

In recent years much attention has been paid to vascular studies of the navicular bone in health and disease; however, the relative importance of these studies has overshadowed biomechanical factors which may yet prove to be of importance. This paper outlines the pertinent anatomy, and discusses current concepts in the aetiology and pathogenesis of the disease. It describes the treatment regimens which are based on biomechanical considerations and compares the results of some currently employed techniques. All aspects of navicular disease remain controversial. This paper is not intended to review or debate all current information on the subject. It reviews information on only biomechanical considerations in an attempt to focus attention on these aspects of treatment.

Animals↗

A study of 118 cases of navicular disease: clinical features.

The clinical features are reported from 118 horses (mean age 9.2 years) which were diagnosed as suffering from navicular disease using predetermined criteria. The animals were used for a variety of purposes and had been lame for periods between 1 and 72 months. The majority of cases (84.7%) had been treated using various techniques before evaluation. The severity of lameness was related to the duration of clinical signs: 78% of horses were bilaterally affected but there was no left:right limb predominance. Broken foot/pastern axes were recorded in 75% of horses while 45% also exhibited mediolateral foot imbalance. Muscle atrophy was recognised in 77% of animals which appeared to be related to limb affliction. The cranial phase of the stride was reduced in 38% and caudal phase shortened in 16% of horses. These abnormalities were related to the degree of lameness. Flexion of the distal joints increased the severity of lameness in 64% of the animals while extension was positive in 41% of instances. Turning in the direction of the lame limb exacerbated lameness in 95% of horses. Only 11% of animals responded to the use of hoof testers and 3% to foot percussion. A range of responses to local analgesia of the palmar digital nerves was recorded but 91% (of 49) of animals exhibited a positive response to local analgesia of the distal interphalangeal joint, and 92% (of 23) of horses responded to local analgesia of the navicular bursa.

Animals↗

A study of 118 cases of navicular disease: radiological features.

Dorsoproximal-palmarodistal oblique, lateromedial and palmaroproximal-palmarodistal oblique radiographic projections were used with standard techniques to examine 118 horses with clinical signs of navicular disease. All radiological features which have previously been reported as significant changes in the navicular bones of horses with navicular disease were recorded. Comparisons were made between these features in lame limbs and sound limbs in unilaterally lame horses and most lame limbs and least lame limbs in bilateral but asymmetrically lame animals. Their relationship to the degree of lameness was also analysed. No relationships were identified between the characteristics of distal border synovial invaginations, flattening and/or thinning of the flexor cortex and limb distribution or severity of lameness. Defects in the flexor cortex, proximal border remodelling, medullary trabecular disruption and medullary sclerosis appeared to be related to limb affliction and severity of lameness while proximal border enthesophytes, and poor flexor corticomedullary demarcation presented evidence of a relationship to the grade of lameness. Poor flexor corticomedullary demarcation and fragmentation of the distal border were related to the severity of lameness in bilateral but asymmetrically affected horses. The presence of peri-articular osteophytes and mineralisation of the flexor digitorum profundus were too infrequently recognised to permit meaningful data evaluation.

Animals↗

A study of 118 cases of navicular disease: treatment by navicular suspensory desmotomy.

The 118 horses diagnosed as suffering from navicular disease by prospective criteria were treated by desmotomy of the ligamenta sesamoidea collateralia (navicular suspensory desmotomy). Three techniques were used and a standard post-operative programme was followed with clinical and radiological evaluations at 6-monthly intervals for periods of 6-36 months after surgery. At 6 and 36 months after treatment, 76% and 42.9% of horses were sound respectively. The clinical features of age, period of lameness, severity of lameness and angular limb deformities adversely affected response to surgery. The presence of flexor cortex defects, proximal border enthesophytes, mineralisation of the flexor digitorum profundus tendon and medullary sclerosis were also associated with a diminished response. There were few (1.7%) changes in the radiological appearance of distal border synovial invaginations during the follow-up period. By contrast, the majority (67.3%) of flexor cortex defects changed. Other radiological features changed at a low frequency but there was no association between radiological change and clinical outcome.

Animals↗

Fractures of the lateral malleolus of the tibia in 16 horses.

Clinical and radiological features of 16 horses with fractures of the lateral malleolus of the tibia are reported. The paper describes surgical techniques used, results obtained and discusses justification for removal. Fourteen fractures were unilateral and two bilateral. There was no left:right disparity. The history included a known traumatic incident in 14 cases. All animals had a tarsocrural joint effusion and 10 had palpable thickening of the lateral collateral ligaments. Crepitus was also palpable in 10 horses. The fracture was identified in all dorsoplantar and 14 of 18 dorsomedial-plantarolateral oblique radiographic projections. Nine fractures were simple and 9 comminuted. All fractures were removed via a tarsocrural arthrotomy. Approaches were dorsolateral in 14 joints, plantarolateral in 3 and dorsolateral and plantarolateral in 1. After an ascending exercise programme horses returned to work 6 months after surgery: 15 horses were free of lameness after 17-62 months, with 13 animals performing at a level similar to pre-injury standard.

Animals↗

Congenital parvovirus infection.

A case of congenital parvovirus (B19) viraemia with associated thrombocytopenic purpura and platelet antigen incompatibility in an infant is reported. Results of laboratory investigations indicated that the baby was infected in utero.

Antigens, Human Platelet↗