Fetlock annular ligament desmotomy: A report of 24 cases

Restriction of free movement of the flexor tendons through the fetlock canal results in lameness. The commonest cause was chronic synovitis of the digital sheath. The condition is characterised by an unremitting lameness, synovial distension and a notch on the caudal aspect of the limb. The condition can be relieved by section of the annular ligament of the fetlock. In a series of 24 cases 16 horses returned to work with no recurrence of lameness, three cases were lost to follow up and five animals remained lame; three of these had intercurrent disease.     

Ultrasonographic evaluation of fetlock annular ligament constriction in the horse

The diagnosis of restriction of free movement of the flexor tendons through the fetlock canal usually rests on the characteristic clinical appearance of this condition, or airtendography. In a series of seven normal Warmblood horses and 16 diseased horses of various breeds, the efficacy of ultrasonography in the diagnosis of this condition was determined. In normal limbs, the annular ligament is a very thin structure usually not visible on sonograms. In diseased limbs, ultrasonography outlined flexor tendon injury, distension and thickening of the digital sheath, peritendovaginal tissue proliferation and thickening of the annular ligament. Four different types of constriction syndrome were noticed. The first type (nine cases), was characterised by thickening of the annular ligament and distension of the digital sheath; the second type (three cases) was dominated by distension of the digital sheath; the third type (three cases) was characterised by superficial digital flexor tendon injury and thickening of the annular ligament and in the fourth type (one case), the constriction resulted from distension of the digital sheath and extensive peritendovaginal tissue proliferation.     

Treatment of chronic digital septic tenosynovitis in 12 horses by modified open annular ligament desmotomy and passive open drainage

A modified open annular ligament desmotomy followed by passive open drainage was used to treat 12 horses with chronic digital septic tenosynovitis due to trauma in the form of open wounds or self-sealing punctures. The surgical approach included complete transection of the palmar/plantar annular ligament of the fetlock and proximal digital annular ligament, which facilitated the removal of fibrin, selective debridement and synovectomy, followed by lavage of the digital sheath. The incision was partially closed leaving a 2 cm gap open distally to allow for passive open drainage. Gentamicin was administered intrathecally during surgery. Postoperatively the horses received ceftiofur and non-steroidal anti-inflammatory drugs. A sterile bandage was used to protect the wound until the gap had healed completely by second intention. Infection was controlled in 11 of the horses which all returned to their previous levels of work, but one horse was euthanased as a result of the persistence of the infection and financial considerations.     

Desmitis of the fetlock annular ligament in the horse

Desmitis of the fetlock annular ligament was diagnosed in 30 horses during a period of eight years. Most of the horses had been lame for a prolonged period and had chronically distended digital flexor tendon sheaths. Air tendograms demonstrated thickened palmar or plantar annular ligaments. In 25 horses the ligament was cut longitudinally; of these, 16 horses returned to full work without any difficulty and one became sound after a second operation. Follow up time varied from three months to seven-and-a-half years. None of the five untreated horses returned to work.     

Endoscopically Assisted Annular Ligament Release in Horses

An endoscopically assisted technique for internally dividing the palmar or plantar annular ligament was developed in six cadaver limb specimens and two anesthetized horses. Under arthroscopic view, a slotted cannula was inserted into the digital sheath through a stab wound proximal to the annular ligament and advanced through the fetlock canal superficial to the flexor tendons with the slot oriented toward the fibers of the annular ligament. Division of the annular ligament by 90-degree tipped open and guarded blades was observed and verified by direct arthroscopic view. At necropsy, complete division of the annular ligament without iatrogenic damage to the neurovascular structures was confirmed by dissection. Annular ligament division was performed in seven horses with complex tenosynovitis conditions. Tenoscopic examination and removal of tendon and digital sheath adhesions, masses, and bands was followed by endoscopically assisted annular ligament transection. At follow-up, five horses were sound athletes without recurrent digital sheath problems, one horse had residual lameness, and one horse was still convalescing.     

Tenosynovitis of the digital flexor tendon sheath and annular ligament constriction syndrome caused by longitudinal tears in the deep digital flexor tendon: a clinical and surgical report of 17 cases in warmblood horses

REASONS FOR PERFORMING STUDY: Inflammation of the digital flexor tendon sheaths is a chronic and nebulous condition often unresponsive to medical and surgical treatment. OBJECTIVES: To evaluate the incidence of longitudinal tears (LT) as the underlying cause of chronic tenosynovitis and annular ligament constriction syndrome (ALCS) in warmblood horses. METHODS: The records of 25 horses with chronic tenosynovitis and ALCS in which tenoscopical inspection of the digital flexor tendon sheath (DFTS) was performed between 1999-2000 were reviewed. Of 25 horses, 17 were diagnosed with an LT in the deep digital flexor tendon (DDFT). All horses had a history of distension of the DFTS and/or signs of an ALCS. All cases presented typical signs of a chronic inflamed DFTS on ultrasonography and 11 horses showed ultrasonographic changes (echogenic material or an irregular outlining) at the lateral or medial border of the DDFT. The diagnosis of LTs of the DDFT was established in all cases by tenoscopy. Surgical treatment consisted of removal of the torn collagen fibrils using a mechanical resector and decompressing the fetlock canal by a transection of the palmar annular ligament (PAL) using a hook knife under tenoscopic control. RESULTS: Ten horses became sound and resumed their previous level of work, 3 horses remained lame, 4 horses returned to previous level of work but needed intrasynovial treatment of the DFTS and reduced competition frequency to remain sound. CONCLUSIONS: Horses presented with chronic inflamed DFTS and/or ALCS might suffer from LTs in the DDFT; however, the diagnosis cannot be established with absolute certainty using only ultrasonography. Longitudinal tears should be suspected if ultrasonographic changes are present lateral or medial to the border of the DDFT but tenoscopical examination of the tendon sheath is essential to establish an accurate diagnosis and an effective treatment. POTENTIAL RELEVANCE: The presence of these LTs might explain why some cases of chronic tenosynovitis of the digital flexor tendon sheath and/or ALCS do not respond on surgical transection of the PAL alone without tenoscopy.     

Luxation of the metacarpophalangeal and metatarsophalangeal joints in horses

Lateral or medial luxation of the metacarpophalangeal or metatarsophalangeal (fetlock) joint in 10 horses is presented. Closed and open fetlock luxation each occurred in five horses. Horses were treated by cast immobilisation after debridement of soft tissue and joint lavage in cases of open luxations. Suture apposition of a ruptured collateral ligament was attempted in three cases. Antibiotic therapy was used in all cases of open fetlock luxation but non-steroidal anti-inflammatory medication was used inconsistently. Whether closed or open, fetlock luxations had a good prognosis for return to breeding status. After treatment, seven horses were used for breeding, one horse was ridden for nine years, one horse remained lame and was destroyed and one horse was lost to follow up.     

Retrospective evaluation of surgical versus conservative treatment of keratomas in 41 lame horses (1995-2001)

A keratoma is a rather uncommon disorder of the equine hoof that can lead to lameness. Few quantitative data exist about the prognosis of different treatment regimens. The outcome of 41 cases that were presented to the Department of Equine Sciences in the period 1995-2001 and that were treated according to different regimens was retrospectively evaluated. All horses showed lameness that could be attributed to the keratoma: 23 (56%) were treated surgically using a standardized procedure, while the other 18 (44%) were treated conservatively. Results were based upon 35 horses; 6 were lost to follow-up. Range of recovery time for the surgically treated patients, was 2-12 months and for the conservatively treated group 2 weeks to 6 months. Of the surgically treated patients 83% (n =23) returned to the same or higher performance level as before the onset of the lameness, as opposed to 42% (n = 12) of the conservatively treated horses (p<0.05). The average hospitalization period was significanty longer for the surgically treated patients (35 vs. 5 days, p<0.05). It is concluded that surgical excision of the keratoma is the preferred treatment for horses suffering from lameness caused by a keratoma, because the better outcome outweighs the longer hospitalization and the longer overall recovery time.     

Endoscopy of the Digital Flexor Tendon Sheath in Horses

An arthroscopic procedure for examination of the digital flexor tendons and tendon sheath was developed in 16 equine limbs and 12 horses. Distension of the tendon sheath and insertion of the arthroscope was accomplished through a cul-de-sac on the palmar or plantar surface of the tendon sheath 1 to 2 cm palmar or plantar to the digital neurovascular structures and between the annular ligament and proximal digital annular ligament. A single arthroscope entry point allowed examination of all regions of the tendon sheath cavity and most surfaces of the digital flexor tendons within the sheath. Distal to the fetlock, surgical procedures could be performed through additional entry portals on the lateral, medial, or palmar surfaces of the tendon sheath. The palmar digital vessels and nerves were avoided by palmar placement of the instrument incisions and insertion of a needle before incising the skin. The fetlock canal and proximal regions of the tendon sheath were examined by redirecting the arthroscope. Flexion of the fetlock aided passage of the arthroscope into the proximal tendon sheath regions. Evaluation of the palmar surface of the superficial digital flexor tendon was limited by the midline attachment of the tendon sheath, otherwise the surfaces of the tendons and tendon sheath could be examined with 25 degrees and 70 degrees arthroscopes. The tendon sheath was more tightly invested to the tendons in the proximal regions, limiting the arthroscope movements and second instrument access.     

Tenoscopic examination and proximal annular ligament desmotomy for treatment of equine "complex" digital sheath tenosynovitis

OBJECTIVE: To determine the outcome of horses with "complex" digital tenosynovitis treated by tenoscopic proximal annular ligament desmotomy and resection of synovial masses or adhesions, or both, within the digital sheath. STUDY DESIGN: Retrospective evaluation. ANIMALS OR SAMPLE POPULATION: Twenty-five horses with a clinical and ultrasonographic diagnosis of palmar or plantar proximal annular ligament constriction and ultrasonographic evidence of synovial masses or adhesions within the digital tendon sheath. METHODS: Each horse had tenoscopic surgery for annular ligament desmotomy combined with adhesiolysis and/or synovial mass resection. Mean follow-up time was 3.4 years. Spearman's rank correlation was used to assess the relationship between functional outcome or cosmetic results and preoperative variables including duration of clinical signs, digital sheath synovial fluid total protein concentration and nucleated cell count, thickness of the palmar or plantar proximal annular ligament (PAL), severity of adhesions, severity of synovial masses, degree of synovial distention, or limb affected. RESULTS: A total of 18 (72%) horses returned to athletic soundness, 4 were improved but not sound, and 3 were not improved. Cosmetic outcome was normal in 10 horses, improved but not normal in 12, and not improved in 3 horses. Cosmetic and functional outcome were significantly adversely affected by the duration of clinical signs and the severity of synovial masses. CONCLUSIONS: With appropriate tenoscopic surgical attention, horses with complex tenosynovitis syndrome characterized by synovial masses, adhesions, or both adhesions and masses, and PAL constriction, have a good prognosis for return to athletic soundness. CLINICAL RELEVANCE: Horses with PAL constriction and additional digital tendon sheath pathology such as adhesions and synovial masses have a 72% chance of returning to sound athletic performance, however 60% of horses retain some degree of cosmetic blemish in the affected limb. There is an inverse relationship between the duration of clinical signs and outcome, and therefore, prompt surgical attention is advised.     

Use of a radiofrequency probe for tenoscopic-guided annular ligament desmotomy

Reasons for performing study: Annular ligament desmotomy is commonly performed in horses with chronic tenosynovitis. Previously reported tenoscopic techniques have limitations related to haemorrhage and awkward instrumentation. Radiofrequency (RF) energy affords precision and excellent haemostasis and may be a good alternative to sharp transection of the annular ligament in horses. Objective: To describe a technique for using a RF probe for tenoscopic‐guided annular ligament desmotomy and to report the clinical outcome of horses in which it was performed. Methods: Cadaver specimens (n = 14) and live horses undergoing unrelated terminal procedures (n = 2) were used to optimise the tenoscopic‐guided RF annular ligament desmotomy technique. Records were examined for all horses undergoing annular ligament desmotomy with an RF probe from 2003 to 2008 for which follow‐up of >1 year post operatively was available. Results: The annular ligament was successfully transected in the cadaver and live horse model limbs using 2 different commercially available RF probes. Complete transection was achieved with practice and confirmed on gross dissection. Histopathology did not reveal any collateral damage to surrounding tissue. Follow‐up of >1 year was available for 6 of 7 clinical cases. Four of 6 horses returned to work. Owners were satisfied with the outcome in all cases. Conclusions: Desmotomy using a RF probe allows precise tissue transection under tenoscopic guidance without damage to surrounding structures or haemorrhage. With experience, it is an easily performed technique. In clinical patients, an acceptable outcome may be expected. Potential relevance: Tenoscopic‐guided RF annular ligament desmotomy offers advantages, including reliable haemostasis and precise tissue transection, over previously reported techniques and is a viable surgical alternative for treating horses with annular ligament desmitis and other complex pathology within the tendon sheath.     

Prevalence and response to surgical treatment of lateral palmar intercarpal ligament avulsion in horses: 37 cases (1990-2001)

OBJECTIVE: To clarify the diagnosis of avulsion of the lateral palmar intercarpal ligament (LPICL), correlate avulsion of this ligament with lameness, determine the prevalence of avulsion of the LPICL in a hospital population, and evaluate the response to surgical removal of the avulsion fragment in horses. DESIGN: Retrospective study. ANIMALS: 37 horses with avulsion of the LPICL. PROCEDURE: Medical records and radiographs of horses with avulsion of the LPICL were reviewed; follow-up information was obtained from race records and from owners via a telephone survey. RESULTS: Of 6,418 horses evaluated for forelimb lameness from March 1, 1990, to December 31, 2001, 37 (0.5%) had avulsion of the LPICL; each horse had a discrete fragment associated with avulsion of the ligament origin from the ulnar carpal bone. Twenty-six horses underwent arthroscopic fragment removal; 20 of 22 (91%) horses for which follow-up information was available returned to work. Of 9 horses treated conservatively, 5 returned to work. Odds ratio calculations indicated that horses treated surgically were 8 times as likely to return to work than those not treated surgically. Twelve horses had LPICL avulsion without concurrent osteochondral fragmentation in the same or additional joints; follow-up information was available for 9 of those horses, of which 8 returned to athletic work. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, discrete avulsion of the LPICL can be a cause of lameness and arthroscopic debridement may be the treatment of choice. Prognosis for return to work of horses with avulsion of the LPICL is good.     

Retrospective study of palmar/plantar annular ligament injury in 71 horses: 2001-2006

REASON FOR PERFORMING STUDY: Constriction of the digital flexor tendon sheath (DFTS) and its contents by the palmar/plantar annular ligament (PAL) is well recognised. However, primary injury of the PAL has not been well documented. OBJECTIVES: To describe the clinical features of PAL injury, determine its prevalence with or without subcutaneous fibrosis and/or concurrent injury within the DFTS, and assess response to treatment. METHODS: Horses were selected for inclusion based upon clinical features consistent with PAL injury and the presence of a thickened PAL (> or =2 mm) verified ultrasonographically. A retrospective analysis of case records from 3 clinics was performed. Details of breed, age and use, and results of clinical and ultrasonographic assessments and response to treatment were recorded. Horses were treated conservatively or surgically by desmotomy of the PAL, with or without tenoscopic evaluation of the DFTS. A telephone questionnaire was performed to assess response to treatment. RESULTS: Seventy-one horses were included in the study and middle aged or older general purpose riding horses predominated. PAL desmopathy occurred more frequently in hind- than in forelimbs. The method of treatment, thickness of the PAL or presence of subcutaneous fibrosis did not significantly affect prognosis; however, <50% of horses were able to return to athletic function. There was a trend for horses with PAL desmopathy alone to have the best outcome. Bilateral thickening of the PAL or concurrent fore- and hindlimb injuries had a negative effect on prognosis, as did the simultaneous presence of subcutaneous fibrosis and lesions within the DFTS. CONCLUSIONS AND CLINICAL RELEVANCE: PAL injury is characterised by a convex contour of the palmar/plantar aspect of the fetlock, associated with thickening of the ligament with or without subcutaneous fibrosis. Bilateral PAL thickening is common in older horses, ponies and cobs; however, bilateral PAL enlargement is often present with only unilateral lameness. Treatment methods used in this study did not appear to influence outcome significantly.     

Osteochondral fragmentation of the plantar/palmar proximal aspect of the proximal phalanx in racing horses

SUMMARY The clinical presentation and outcome of treatment is presented for 26 cases of osteochondral fragmentation of the plantar/palmar proximal aspect of the proximal phalanx. Twenty-three were racing Standardbreds and three were racing Thoroughbreds. The most common reason for presentation was an inability to run straight at high speed. Only eight horses presented for lameness, although on examination 19 were lame. A positive flexion test was recorded in 90% of affected fetlock joints and effusion in 48%. Arthroscopic fragment removal was performed on 23 occasions in 21 horses and arthrotomy in one horse. Of the 16 horses that had returned to racing, 12 had improved their performance, while three showed no improvement, and one was retired for other reasons. In three horses refragmentation occurred after surgery, two of which had improved after initial arthroscopic removal. Degenerative changes within the fetlock joint were detected at surgery in eight horses. Of the four horses treated conservatively, one returned to its previous level of performance temporarily after intra-articular medication, one showed no improvement and two were still resting. Plantar/palmar osteochondral fragmentation of the proximal aspect of the first phalanx is a common cause of low-grade lameness in racing horses, and arthroscopic removal results in improvement in race performance in a high percentage of cases.     

Prevalence of osteochondrosis in the limb joints of South German Coldblood horses

This study aimed to quantify the factors associated with the prevalence of the radiological signs of osteochondrosis (OC) and osteochondrosis dissecans (OCD) in South German Coldblood (SGC) horses. The prevalence of OC and OCD in fetlock and hock joints was analysed in 167 young coldblood horses with a mean age of 14 months. The presence of at least one osteochondrotic lesion (OC) in fetlock or hock joints was documented for 61.7% of the horses and 26.9% of the horses had osseus fragments. Osteochondrotic findings at the dorsal aspect of the sagittal ridge of the third metacarpal/metatarsal bone were seen in 53.9% of the horses and palmar/plantar osseous fragments in fetlock joints in 16.2% of the horses. Hock joint OC was found in 40.1% of the horses and hock OCD in 0.6%. Osteochondrotic findings in the distal part of the tibia were prevalent in 28.1% and in the lateral trochlea tali in 17.4% of the horses. The sex of the investigated horses significantly influenced the prevalence of OC in fetlock and hock joints, as well as the findings in the distal part of the tibia and lateral trochlea tali. Age at radiological examination was significant for the prevalence of OC in hock joints, palmar/plantar osseous fragments in fetlock joints and osteochondrotic findings in the distal part of the tibia. Female horses showed a 2-fold higher risk for OC in fetlock and hock joints than male horses. The distribution of the affected horses by age classes showed that radiographic signs of OC in fetlock and hock joints significantly increased at an age of about 1 year. We can conclude from our study that fetlock and hock OC is a prevalent radiographic finding in more than 1-year-old female and male SGC horses.     

Evaluation of clinical and laboratory variables as prognostic indicators in hospitalised gastrointestinal colic horses

The present prospective study included 106 horses referred to the Department of Large Animal Sciences, The Norwegian School of Veterinary Science, as non-responders to the initial colic treatment in general practise. In 14 of these cases a required surgical treatment was not performed due to economical or other reasons and were excluded from the study. Clinical and laboratory data were obtained at the arrival in the hospital. The outcome for all analyses was survival/ non-survival. A multivariable logistic regression was performed. The analyses were used in medically (46 horses) and surgically treated cases (46 horses) separately. The same analyses were also run for all 92 horses in a simulated "field" situation, where only clinical variables and D-dimer values were included. The fraction of survivors was 78% in the medical and 48% in the surgical cases. In total 63% of the horses survived. In the final multivariable logistic regression model packed cell volume (PCV) was the only important predictor for medically treated cases, and heart rate and presence of hyperaemic or cyanotic mucous membranes were the predictors in the surgically treated cases as well as in the simulated "field" situation. In conclusion, traditional variables as heart rate, mucous membranes and PCV were the important predictors for the outcome in hospitalised colic cases.     

Subchondral osseous cystic lesions of the elbow of horses: conservative versus surgical treatment

Subchondral osseous cystic lesion of the elbow was diagnosed as a cause of lameness in 6 horses. Persistent lameness and signs of degenerative joint disease developed in the first 3 horses treated conservatively with confinement. Subsequently, 3 horses were each treated by extra-articular enucleation of the cystic cavity via the proximal-medial aspect of the radius. Compared with conservative management, better long-term success (determined by return of athletic soundness and less evidence of degenerative joint disease) was achieved with surgical curettage of elbow subchondral cystic lesions.     

Use of a fetlock support brace to manage lacerations of equine flexor tendons

A retrospective analysis of 15 cases of flexor tendon lacerations managed with a fetlock support brace between 2004 and 2008 was performed. Information was gathered concerning exact nature of the injury, treatment details and outcome. Limbs involved included 2 forelimbs and 13 hindlimbs. Eight of fifteen horses (53%) presented with a dropped fetlock, elevated toe or both when bearing weight on the affected limb. General anaesthesia was performed on 7/15 cases to further evaluate and treat the wound, 8/15 cases were managed with local anaesthesia and/or sedation only. The brace was applied within 14 days of presentation and maintained for a mean of 106 days. Sixty percent of cases were sound and used as intended and an additional 20% were sound but at a lesser level of work. Horses with flexor tendon lacerations can be managed with a fetlock support brace alone and have a similar outcome with shorter hospitalisation than horses managed by other methods.     

Cylindrical press-fit osteochondral allografts for resurfacing the equine metatarsophalangeal joint

OBJECTIVE: To investigate the feasibility of resurfacing the equine fetlock joint using cylindrical, orthotopic, press-fit, osteochondral allografts. STUDY DESIGN: Experimental study. ANIMALS: Ten mature, mixed-breed horses. METHODS: Cylindrical, osteochondral grafts (6.5-mm diameter) were harvested aseptically from cadaveric equine metatarsophalangeal joints. Allografts were transplanted into 6 horses; 4 horses were sham operated. The surgical approach involved creation of a bone block at the origin of the medial collateral ligament and luxation of the metatarsophalangeal joint. Grafts were placed into the medial and lateral metatarsal condyles. Radiographs were taken at 8 and 25 weeks, and lameness was evaluated at 25 weeks. Horses were killed at 25 weeks. Analyses included gross evaluation, microradiography, paravital staining, light microscopy, and cartilage biochemistry. RESULTS: No complications occurred that could be attributed to the surgical procedure. Graft congruency with the surrounding articular cartilage was fair to excellent. Two horses were sound at 25 weeks. Most grafts had more than 90% articular cartilage coverage, and histologic and microradiographic analysis revealed good graft incorporation and articular cartilage survival. Sulphated glycosaminoglycan concentration was decreased in grafted tissue. CONCLUSIONS: We attribute the viability of osteochondral allografts in the equine fetlock to adequate congruency, stable graft fixation, and the use of orthotopic tissue. Host response to the allograft bone tissue did not affect cartilage viability. CLINICAL RELEVANCE: Before clinical use, improvements to instrumentation are required that would decrease damage to grafts and minimize technique-associated incongruencies of the articular surface at the time of grafting. Larger grafts would also likely be required to resurface a greater surface area.     

Efficacy of thermal cautery for intermittent dorsal displacement of the soft palate as compared to conservatively treated horses: Results from 78 treadmill diagnosed horses

Reasons for performing study: Previously, objective comparisons of surgical procedures to relieve dorsal displacement of the soft palate (DDSP) have been limited by the presumptive basis of the diagnostic measures applied. Objectives: To assess and compare the efficacy of thermal cautery surgery to conservatively treated controls in racehorses definitively diagnosed with idiopathic intermittent DDSP. Hypothesis: Both conservative and surgical treatments have a beneficial result on racing performance in racehorses affected with DDSP. Methods: Race records were obtained for Thoroughbred racehorses definitively diagnosed with DDSP using highspeed treadmill endoscopy. Racing performance was assessed based on prize money won. Results: Forty‐eight horses that underwent thermal cautery and 30 conservatively treated controls were included. Pretreatment earnings significantly decreased in the race immediately prior to diagnosis. A high proportion of previously raced horses returned to racing after both treatments (90–96%). Intrahorse comparison of earnings in 3 races pre‐ vs. post treatment showed that 53% of conservatively treated horses and 36% of the thermal cautery group had improved performance. Although the difference between these 2 groups may be interpreted as being clinically significant, it was not statistically significant. Conclusions and potential relevance: A higher percentage of conservatively treated controls had improved individual performance compared to horses treated with thermal cautery. Thermal cautery appears less effective than other previously published surgical treatments for DDSP. Comparison of the 2 treatment methods should be interpreted cautiously because treatments were not randomised, resulting in baseline variability between groups.