The effect of intralesional injection of bone marrow derived mesenchymal stem cells and bone marrow supernatant on collagen fibril size in a surgical model of equine superficial digital flexor tendonitis.

REASONS FOR PERFORMING STUDY: Collagen fibril size is decreased in repair tissue following tendon injury compared to normal tendon matrix in horses. Mesenchymal stem cells have been suggested to promote regeneration of tendon matrix rather than fibrotic repair following injury, although this concept remains unproven. OBJECTIVES: To explore the hypothesis that implantation of autologous mesenchymal stem cells derived from bone marrow into a surgically created central core defect in the superficial digital flexor tendon (SDFT) of horses would induce the formation of a matrix with greater ultrastructural similarities to tendon matrix than the fibrotic scar tissue formed in control defects. METHODS: Tissue was collected 16 weeks after induction of injury and 12 weeks after treatment from normal and injured regions of control and treated limbs of 6 horses and examined using transmission electron microscopy. Collagen fibril diameters were measured manually with image analysis software and surface areas calculated. Three parameters assessed for normal and injured tissue were mass average diameter (MAD), collagen fibril index (CFI) and the area dependent diameter (ADD). RESULTS: Normal regions from both treated and control limbs displayed higher MAD and CFI values, as well as a characteristic bimodal distribution in fibril size. Injured regions from both treated and control limbs displayed significantly lower MAD and CFI values, as well as a unimodal distribution in fibril size. There were no significant differences between treated and control limbs for any of the parameters assessed. CONCLUSIONS: Intralesional injection of autologous bone marrow derived mesenchymal stem cells had no measurable effect on the fibril diameter of collagen in healing tissue in the SDFT of this experimental model 16 weeks after injury. POTENTIAL RELEVANCE: Favouring matrix regeneration over fibrotic repair may not be the mechanism by which autologous mesenchymal stem cells assist healing of tendon injury.

A case of multiple epitrichial sweat gland ductal carcinomas in a horse.

This case report describes a rare epitrichial sweat gland ductal carcinoma in a 14-year-old horse and is the first report of multiple carcinomas of this type in horses. Although several tumours developed, mostly on the distal extremities, over a 2-year period, the horse remained otherwise healthy. Topical treatment with imiquimod was successful for many of them.

Effect of age at presentation on outcome following arthroscopic debridement of subchondral cystic lesions of the medial femoral condyle: 85 horses (1993--2003).

REASONS FOR PERFORMING STUDY: Subchondral cystic lesions of the medial femoral condyle (SCMFC) are well documented in horses < or =3 years; arthroscopic debridement or enucleation of the cyst is currently the surgical treatment of choice. However, studies of occurence and outcome following surgery in older horses are lacking. OBJECTIVE: To identify factors important in outcome for horses with SCMFC treated by arthroscopic debridement. HYPOTHESIS: Age of horse at presentation has a significant influence on return to work following arthroscopic treatment for SCMFC. Clinical and diagnostic findings are also significant with respect to prognosis. METHODS: A retrospective review of medical records from 6 equine referral centres identified 85 horses that underwent arthroscopic debridement of SCMFC. Clinical examination, radiographic and arthroscopic findings were analysed together with follow-up data. Univariable analysis and multivariable logistic regression models were used to determine factors affecting return to soundness. Event-time analysis was performed to evaluate return to work. RESULTS: Older horses (>3 years) were less likely to return to soundness (P = 0.02) or to work (P = 0.04) than younger horses (< or = 3 years). Of 39 horses age 0-3 years, 25 (64%, 95% CI 49-79%) returned to soundness. Of 46 horses age >3 years, 16 (35%,95% CI 21-49%) returned to soundness. In addition, cartilage damage at sites other than the SCMFC negatively affected prognosis (P = 0.05). The hospital where treatment was performed had no influence on return to soundness. CONCLUSIONS: Older horses carry a worse prognosis for both return to soundness and return to work. POTENTIAL RELEVANCE: It is important for clients to be made aware of the difference in outcome between age groups.

Use of a bioabsorbable implant for the repair of severed digital flexor tendons in four horses.

A new bioabsorbable implant composed of poly-L-lactic acid was used to repair the severed digital flexor tendons of four horses. The limbs were immobilised with distal casts which were changed after six to eight weeks and removed after 12 to 16 weeks. The horses were followed clinically and ultrasonographically for from seven to 19 months after the surgery. The ultrasonographic examination after the cast had been removed showed that the implants had been well incorporated into scar tissue. Two of the horses were mildly lame at the trot seven months after the surgery, but had returned to work after 12 months. The other two horses are still lame. No complications were observed with the implant.

Scapulohumeral osteoarthritis in 20 Shetland ponies, miniature horses and falabella ponies.

This paper describes the clinical and diagnostic features of 20 cases of scapulohumeral osteoarthritis in Shetland ponies, miniature horses and falabella ponies. The history and clinical signs were similar in all the cases Radiographically they all had consistent changes which consisted predominantly of articular osteophytes and periarticular enthesiophytes. Six of the cases had radiographic evidence of dysplasia of the scapulohumeral joint, although it was uncertain whether this was a primary or a secondary finding. No specific treatment appeared to be advantageous. At follow up, six of the ponies had to be euthanased owing to continuing severe lameness; the other 14 ponies remained lame, but were maintained at pasture by the occasional use of oral non-steroidal anti-inflammatory drugs. No definitive aetiology for the condition was identified, but it is proposed that an underlying dysplasia, or lack of collateral support may predispose the scapulohumeral joint of miniature horse breeds to the disease.

Effects of analgesia of the distal interphalangeal joint or palmar digital nerves on lameness caused by solar pain in horses.

OBJECTIVE: To determine if pain of the dorsal margin of the sole in horses can be attenuated by anesthesia of either the distal interphalangeal (DIP) joint or the palmar digital (PD) nerves. STUDY DESIGN: A unilateral forelimb lameness was induced by creating solar pain. Response to administration of local anesthetic or saline solution into the DIP joint and to administration of local anesthetic around the PD nerves was evaluated. ANIMALS: Six horses. METHODS: Lameness was induced by creating pressure on the dorsal margin of the sole by screwing set-screws into a nut welded to the inside of each branch of a shoe. Gaits were evaluated before and after application of set-screws and after a local anesthetic or saline solution was administered into the DIP joint and, in a second trial, after a local anesthetic was injected around the PD nerves. Gaits recorded on videotape were evaluated, and lameness scores were assigned to each gait. RESULTS: Lameness scores were high after application of set-screws and remained high after saline solution was administered into the DIP joint. Scores decreased significantly (P < or = .05) after a local anesthetic was administered into the DIP joint or around the PD nerves. CONCLUSIONS: Analgesia of the DIP joint or the PD nerves desensitizes at least a portion of the sole. CLINICAL RELEVANCE: Pain arising from the sole should not be excluded as a cause of lameness when lameness is attenuated by analgesia of the DIP joint or PD nerves.

Melanoma screening: results of the first one-day campaign in Belgium ('melanoma Monday').

BACKGROUND: Although the incidence of melanoma is increasing and many informative campaigns have been organized. The general population is still little informed about this tumour. AIMS: To organize a media campaign, with more relevant information and the opportunity for free skin inspections. METHODS: A 'Task Force' organized a media campaign in April 1999 and convinced 65% of the Belgian dermatologists to give up 4 h of their time to do free skin examinations for skin cancer on Monday 26 April 1999; it was called 'Melanoma Monday'. RESULTS: A total 2767 patients were screened. We found 25 melanomas and suspected 59 basal cell carcinomas. In the following 4 weeks another 141 melanomas were found. These 166 melanomas found in one month represent 15-20% of the total number of melanomas per year in Belgium. SUMMARY: A media campaign with relevant information combined with screening opportunities can lead to the early detection of melanomas in a large number of patients and can continue to alert people at risk in the following weeks.

Radiological study to evaluate suspected scapulohumeral joint dysplasia in Shetland ponies.

A radiological study was performed to test the hypothesis that osteoarthritis of the scapulohumeral joint in Shetland ponies is secondary to shoulder dysplasia. Animals were selected into 3 groups: Group 1: Shetland ponies with a radiological and clinical diagnosis of scapulohumeral osteoarthritis (n = 8); Group 2: Shetland ponies without forelimb lameness (n = 12); Group 3: Horses/ponies without a history or clinical signs of forelimb lameness (n = 22). Anatomical indices were measured from mediolateral radiographs of a scapulohumeral joint from each animal. There was a significant difference in the mean radius of curvature of the glenoid cavity of the scapula (RCG) between the 3 groups (MANOVA test, P = 0.003). The mean RCG of both Group 1 (P = 0.001) and Group 2 (P = 0.022) was significantly greater than that of Group 3. There was no significant effect of group on the radius of curvature of the humeral head or on the Conformity Index. There was a significant effect of group on the Glenoid Ratio (MANOVA test, P = 3 x 10(-6)). The mean Glenoid Ratio was significantly lower in both Group 1 (P = 2 x 10(-6)) and in Group 2 (P = 0.006) than in Group 3. These results indicate that the glenoid cavity of the scapula is 'flatter' and 'shallower' in Shetland ponies which we postulate to be a primary dysplasia in this breed.

Endoscopic examination of the tarsal sheath of the lateral digital flexor tendon in horses.

This study was designed to develop a reliable technique for endoscopic examination of the tarsal sheath of the lateral digital flexor tendon of horses. The anatomy of the tendon sheath and associated structures was studied in detail in cadavers before determining portals for the insertion of an arthroscope into the sheath. Approaches into the sheath through the proximal pouch and through the flexor retinaculum, at the level of the sustentaculum tali, were performed and compared in cadavers. The proximal pouch portal permitted visualisation only of the proximal half of the sheath, while the approach through the retinaculum allowed examination of the entire sheath. The normal endoscopic appearance of the tarsal sheath was studied. The endoscopic approach was subsequently used to examine and treat 5 horses with tarsal sheath tenosynovitis, including 2 cases of chronic, traumatic tenosynovitis and 3 of subacute septic tenosynovitis. Four of these horses had fragmentation of the sustentaculum tali. The technique allowed adequate examination of the sheath and debridement of adhesions and lesions within the lumen of the sheath. Fragments dorsal to the medioplantar edge of the sustentaculum tali could not be visualised endoscopically and had to be removed after widening of the wound. All 5 horses survived. Follow-up enquiries (8-31 months) revealed that the horses were all reported to be sound. Four were performing at their previous level of activity, 1 was used for hacking. The 2 cases presented with chronic tenosynovitis had residual sheath distension with no associated loss of function. A prospective study, including longer term follow-up investigation, is currently being performed.