At the 50th annual American Association of Equine Practitioners (AAEP) Convention in Denver, Colo., Dec. 4-8, 2004, Kevin Haussler, DVM, DC, PhD, lecturer in anatomy in the department of biomedical sciences, college of veterinary medicine at Cornell University succinctly summed up the perplexing issue of diagnosing and treating sacroiliac pain when he concluded his presentation with these words: "I've never been so sure about what I do not know and I have never been so unsure about what I do know."
It was apparent that many other veterinarians at the annual convention in Denver felt the same way because they attended the session in numbers that filled the huge room to capacity and more. Staff members from the convention center played the role of ushers as they sought out rare empty seats for late-comers.
The presenters, in addition to Haussler, were Sue Dyson, VetMB, PhD, FRCVS, of the Centre for Equine Studies, Newmarket, England; and Emmanuel Engeli, Vet. Dipl ACVS, ECVS, of Switzerland.
Another of Haussler's comments let the audience know that treatment of sacroiliac problems can be complicated and prolonged. "Unfortunately, there is no quick fix" when sacroiliac problems are involved, he said.
The sacroiliac joint region continues to be an area of confusion for many practitioners because of its deep location and unique anatomical features, Haussler said. The sacroiliac joint, he explained, is a synovial articulation located at the junction between the ventral wing of the ilium and the dorsal wing of the sacrum. To the horseman, the area under discussion is from the point of the croup downward.
The sacroiliac joint, Haussler said, "functions as the pelvic attachment to the axial skeleton, providing support during the weight bearing and helping to transfer propulsive forces of the hindlimb to the vertebral column." Problems that occur within the sacroiliac joint region, he noted, include osteoarthritis, ilial wing stress fractures, tuber sacrale asymmetry, desmitis (ligament inflammation), and muscle strain.
Because of inaccessibility and lack of sophisticated techniques in the past, Haussler said, diagnosis of the problem has often been a diagnosis of exclusion. However, the use of ultrasound and nuclear scintigraphy, "have provided new insights into documenting sacroiliac joint pathology." Haussler told his listeners. "Unfortunately, there continues to be limited understanding and research into the pathophysiology of specific sacroiliac joint injuries."
Dyson reported on a study she conducted involving two groups of horses in England. The majority of the horses involved, she said, had a history of reduced performance or unwillingness to work. The diagnosis of sacroiliac joint disease, she said, was made after other causes of hindlimb lameness had been excluded.
"Complaints included lack of hindlimb power, deterioration of quality of movement, change in behavior, reluctance to work on the bit, difficulty in lateral movements, changing legs behind in canter, failure to perform correct flying changes, or refusal to jump," she said. "Some horses had also become awkward to shoe the hindlimbs. The clinical duration of clinical signs ranged from one month to more than one year; however, many riders thought retrospectively that the horse had not been right for about two years or was always inclined to be stiff in the back. In many horses, there had been an insidious onset and progression of clinical signs, and the riders were often unaware of the current degree of gait impairment.
"To an untrained observer, many of the horses appeared clinically normal and had been training and competing up until the time of clinical investigation, but with reduced performance. A second group of horses had a sudden onset of bucking behavior when ridden, tending to buck and kick out simultaneously and sometimes repeatedly to one side."
Most of the horses in the study, she said, were used for either dressage or show jumping, with some used for eventing and the rest for lower-level competition or show jumping.
When examined moving in hand on a hard surface, Dyson said, the most common feature among the study horses with perceived sacroiliac problems was reduced hindlimb impulsion. "Some horses," she said, "had a rolling hindlimb gait, some moved exceptionally widely behind, others moved closely and a few plaited. Many horses had more than one gait abnormality. Stiffness and poor hindlimb impulsion were common features on the longe. A few horses tended to break to canter rather than increase hindlimb impulsion, whereas others showed a poor-quality canter. Clinical signs were invariably worse when the horse was ridden and sometimes only apparent under these conditions. In some horses, the deterioration in gait when the horse was ridden was profound and dramatic."
Among the horses that bucked and kicked, Dyson said, the activity was generally reserved for when they were ridden. When moving in hand or on a lunge line, she said, they appeared to be normal. However, when a rider was up, the horse began bucking and kicking out, with the activity being more pronounced at the canter than any of the other gaits. However, she added, in some of the most severely affected horses, the bucking and kicking also occurred at the walk.
"Some of these horses," Dyson said, "were also extremely reluctant to go forward. In less severely affected horses, kicking behavior only became evident when the horse was asked to collect and work with increased hindlimb engagement."
A part of the study involved injecting the sacroiliac joint of the affected horses with an analgesic and then determining response. The result of that part of the research, Dyson said, surprised many of the researchers because of the dramatic effect.
She had this to say: "Marked improvement in gait was observed in many horses and highlighted the degree of discomfort that the horse had been suffering, despite relatively subtle clinical signs in some horses before injection. Horses generally moved much more freely and willingly and with increased animation. There was improved hindlimb impulsion and a change in balance because of increased engagement of the hindlimbs and subsequent lightening of the forehand. The horses tended to have a more consistent contact with the bit. There was a marked reduction in back stiffness. In several horses that had previously refused to lift either hindlimb from the ground, both hindlimbs could be lifted after infiltration."
There was also a significant change in the behavior of horses that had bucked and kicked out. "Horses that bucked or kicked out," Dyson said, "usually responded dramatically by almost complete cessation of this behavior and marked increase in willingness to move forward (after having the analgesic administered)."
There were a couple of take-home messages from Dyson's presentation. One was that sacroiliac joint problems can dramatically compromise a horse's ability to perform, and the other was that using an analgesic injection can be a valuable technique in diagnosing sacroiliac problems.
More Sacroiliac Diagnostics
Engeli then took the podium to discuss injection techniques. He told the group that sacroiliac disease can be divided into two major etiologic categories--sacroiliac joint osteoarthritis and sacroiliac ligament desmitis. It is crucial to the veterinarian to know exactly what he is dealing with so that he can recommend an appropriate treatment protocol, he said.
Engeli then presented a detailed account of injection procedures aimed at helping to determine whether the problem was in the joint itself or within the ligaments.
Dyson followed with a presentation on the use of scintigrapy in the diagnostic process. Her conclusion was this: "Scintigraphic evaluation of the sacroiliac region, combined with other clinical signs supportive of the diagnosis, is useful in identifying sacroiliac joint (SIJ) disease. However, because of some degree of overlap in the range of radiopharmaceutical uptake between those with presumed sacroiliac joint disease and both normal horses and horses with other causes of lameness, diagnosis should not be based on scintigraphic evaluation alone."
Engeli then discussed the use and limitations of ultrasonography in diagnosing sacroiliac disease. Here was his conclusion: "The obtained information (from ultrasonography) must be interpreted in light of thorough physical and lameness examinations, sacroiliac stress tests, periarticular SIJ analgesia and nuclear scintigraphy in an attempt to differentiate between SIJ disease and sacroiliac ligament desmitis."
Thus, it became evident, there is no magic way in which to obtain a correct diagnosis. And, as Haussler was about to tell them, there is no magic cure to the problem and the prognosis is not always bright.
His opening salvo was this: "Treatment of a sacroiliac joint injury is only effective if the diagnosis is correct. Because definitive diagnosis of sacroiliac joint pathology remains difficult, treatment recommendations are usually supportive and not specific."
The overall care and management of a horse with a sacroiliac joint problem will vary, depending on whether the problem involves osteoarthritis within the joint or desmitis of the ligaments.
"Musculoskeletal health," Haussler reported, "depends on movement and use. Scientific evidence suggests that long-term rest or inactivity is contraindicated for osteoarthritis in humans. Similar recommendations are appropriate for horses with sacroiliac osteoarthritis. Horses that are stalled for the majority of the day or large portions of the year do not have the opportunity to maintain back or pelvic flexibility, which may contribute to sacroiliac joint stiffness and dysfunction."
Exercise can be carried out in hand or on the lunge line minus a rider for several weeks, he said. This allows for movement of the sacroiliac region without the excessive stress associated with weight of the rider.
"In chronic, low-grade sacroiliac osteoarthritis," he informed the group, "a progressive exercise program can be used to help build up the gluteal and hindlimb muscles. A tapering dose of oral phenylbutazone can be given as the exercise is gradually increased. When the horse is comfortable in hand or on the longe line, light riding at a walk and then a trot may be used as long as the horse is monitored daily for willingness and ability to do the work."
When the problem involves ligaments in the sacroiliac region, Haussler said, immediate rest is often called for. However, he was quick to say, extended rest might not be a good thing because it can result in reduced muscle tone that will exacerbate the problem.
Hand-walking for five minutes twice a day for up to five times a week is suggested during the first month of recovery, he said. Backing-up exercises are also recommended for the rehabilitation of the sacroiliac ligament injury. Ground pole and obstacle work can also be effective.
"Exercise is gradually increased as the horse is able for up to a maximum of 30 minutes a day five times a week," Haussler stated. "If the lameness continues to be managed, then short durations of turnout in a small paddock can be used with continued gradual increase in exercise. Periodic re-evaluation is required to monitor the progress of the rehabilitation. It has been reported that it usually takes eight to 10 months of rest and controlled exercise before horses are ready to return to regular training and performance."
Also helpful in alleviating stiffness, Haussler said, are stretching exercises that can be carried out by the owner. With minimal training, he said, horses and their owners can be taught how to do simple but effective passive joint mobilization and stretching exercises to improve both skeleton and limb flexibility.
"These concurrent therapies also help to encourage the owner to participate in the healing process," he said, "and provide close monitoring of a patient's progress."
Haussler also recommended the use of ice packs during the first 24 to 48 hours after a sacroiliac injury to reduce pain, induce muscle relaxation, and reduce inflammation.
Acupuncture and chiropractics have also been effective in a number of cases, he said--a viewpoint also shared by Danny Marks, VMD, who joined the discussion panel.
Haussler also pointed out that drug therapy, plus physical and manipulative therapies, can be helpful in dealing with sacroiliac problems. Called into use, he said, might be a combination of medications such as non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, or muscle relaxants.
However, Haussler told his listeners, very few studies have investigated the efficacy of specific treatment recommendations for sacroiliac joint injuries.
Here is what he had to say concerning prognosis when sacroiliac injuries are involved:
"Long-term follow-up suggests that prognosis for sacroiliac joint injury is poor for return to the previous level of activity. This depends on the amount and extent of sacroiliac osteoarthritis or desmitis present. Some horses may have an improvement in performance or lameness, but most will not be able to return to normal athletic activities because of recurring low-grade lameness. Complete recovery from chronic sacroiliac injury has been reported to be about 47 percent in work by Dr. Leo Jeffcott of England. Most horses will be pasture sound or able to function only at low levels of exercise. Improvements in providing a specific diagnosis of the sacroiliac joint injury will provide affected horses with better and more specific treatment options in the future."
About the Author
Les Sellnow is a free-lance writer based near Riverton, Wyo. He specializes in articles on equine research, and operates a ranch where he raises horses and livestock. He has authored several fiction and non-fiction books, including Understanding Equine Lameness and Understanding The Young Horse, published by Eclipse Press and available at www.exclusivelyequine.com or by calling 800/582-5604.
POLL: University Equine Hospitals