Fetlock Arthroscopy – removal of dorsal plica in case of chronic synovitis.
This competition horse had a history of intermittent forelimb lameness. He had an obvious effusion of the fetlock joint, which was also painful during a flexion test. A joint block of the fetlock joint resolved the lameness.
He had already been treated several times with joint medication – both corticosteroids and ‘Arthramid’. However the beneficial effects of both of these medications started to wear off too quickly (after a couple of months).
X-rays of the joint showed a degree of fetlock arthritis, but more importantly there was a focal area of bone remodelling at the front of the joint. This ‘waist’ that formed is an indication of inflammation within the synovial plica, a shock absorbing pad within the front of the fetlock joint. The ultrasound scan confirmed the thickening and tearing within this structure.
To prevent further inflammation and pain, it was agreed to perform keyhole surgery to remove the enlarged and damaged synovial plica. This was performed at LLEP under a general anaesthetic, with the horse lying on its back on our padded operating table.
The video shows the thickened and swollen fibrous structure – this is usually a thin curtain-like covering over the bone, rather than this lump of gristle ! It was initially removed by sharp dissection, before being removed from the joint. A mechanical resector was then used to debride and smooth over the remaining tissue to allow it to heal with normal scar tissue afterwards. Finally the joint was flushed to remove any loose floating fragments of tissue and the keyhole incisions were closed with single sutures.
After any joint surgery, rehabilitation is an important part of the healing process. After waiting for the sutures to be removed, he was walked in hand for 2 months before starting restricted turnout and a gradual return to exercise levels. He is now back in full work, sound and jumping better than ever.
Download the Fetlock video (270Mb)
Arthroscopy - Hock OCD
OCD (osteochondritis dessecans) is a developmental bone condition. During theformation of bone, a localised lack of blood supply results in one of three abnormal types of bone within a joint – a fragment (or chip), a loose flap of cartilage on a gliding surface, or a bone cyst at the site of load bearing contact.
This horse has very large bone fragments at the most common site of OCD, which is in the tarso-crucal joint of the hock. These fragments form on the distalintermediate ridge of the tibia. It is therefore known as a 'DIRT' lesion.
In some cases, smaller fragments which form here can be clinically silent for most of a horse's life. However this horse presented with a low grade lameness and an obvious effusion (swelling) of the hock joint – also known as a 'bog spavin'. The lameness was resolved with a local anaesthetic joint block.
The radiographs confirmed the presence of these large DIRT lesions, which were present on both hind legs.
Surgery to remove these fragments was undertaken under a General Anaesthetic, using keyhole surgery (arthroscopy). A small 1cm incision wasmade into the joint to allow the camera to be passed into the joint. A second small incision was made for the instruments – this was obviously then enlarged to remove these larger fragments (which were approx. 2cm in size).
Following a thorough examination of the rest of the joint, the fragments were first probed to assess how loose they are, they were then elevated away from the connective tissue that held them in place. Rongeurs were then used to grab and remove the fragments from the joint. Once all fragments were removed the tissue covering the exposed part of the bone was carefully curetted to remove all of the abnormal tissue, so that healthy solid bone was left inside the joint. Finally the joint was flushed out with large volumes of sterile saline to flush away any small particles and debris so that the joint was left clean inside.
Small sutures close the keyhole incisions, which were then removed 2 weeks later. The horse remained on box rest and a controlled walking program for a further 6 weeks before coming back into full work again.
Whilst a small proportion of horses can still have a small degree of joint filling even when back in work, the prognosis for long term athletic use is very good, providing there was no concurrent cartilage damage caused by the fragments rubbing inside the joint before they were removed.
Download the Hock OCD video (117Mb)
Tenoscopy – Manica Flexorum tear
This horse presented with an acute onset 6/10 RH lameness. There was an effusion of the digital flexor tendon sheath (DFTS) along with pain both on distal limb flexion but also on palpation of the borders of the SDFT within the proximal pouch of the DFTS.
Due to the localising clinical findings, an ultrasound scan was performed before any further lameness evaluation or local anaesthetic blocks.
The ultrasound scans below show the thickened manica flexorum (MF) lifted away from the underlying DDFT. This is a clear ultrasonographic finding indicating a MF tear. It is also possible to perform positive contrast radiography to outline the MF, but this was unnecessary in this case due to the clear ultrasound image.
An intra-thecal block of the DFTS was performed to confirm that this was the only source of pain before elective surgery was planned for a week later to allow some of the initial inflammation and swelling to subside.
After routine pre-operative assessment and medication, the horse was then anaesthetised. The use of the hinged and padded ‘crush door’ has been found to make the induction much safer for both horse and handlers. She was then hoisted and moved into the theatre before being placed in lateral recumbency on the padded table. Our anaesthetist has the ability to closely monitor the patients, with ECG, pulse oximeter, expired gasses, capnograph, direct blood pressure, intra-operative blood sampling as well as a ventilator to assist with respiration.
The intra-operative video shows first the normal side of the MF where it is attached to the SDFT, and then in contrast the thickened torn region. The manica is then held in tension whilst it is cut free and removed in its entirety.
We use a rope assisted recovery system for all our patients – and have found it a huge help in helping reduce stumbling and injuries whilst the horses stand again in the padded box.
Following routine bandage changes, this patient returned home 3 days later and remained bandaged until the sutures were removed 12 days after the surgery. After 3 months gentle hand walking she was sound at walk, and 2/10 lame at trot and with only a slight effusion of the DFTS.
At the 6 month follow-up there was further improvement – she was being hacked out daily for up to 45 minutes along with restricted turnout. She was sound at trot both in hand and on the lunge. This was particularly pleasing as there are many cases of DFTS surgery that can take a full 9-12 months to fully heal.
Manica Flexorum tears more commonly occur in the hind legs, whereas linear tears to the DDFT are more often seen in the front legs. It is thought that this is due to the more pronounced over extension of the hind fetlocks during loading, which results free distal edge of the MF being trapped or pinched within the tight fetlock canal. Low grade fibrillation to this distal edge can be treated with localised resection with a mechanical resector, whereas extensive tears are best treated with total resection of the MF.
Download the Manica Tear video (147Mb)
Sinoscopy – Sinus Cyst removal
This sinus cyst was initially identified as an incidental finding on head x-rays that were taken for an unrelated condition.
Sinus cysts will continue to increase in size over time, in some cases large enough to distort both the overlying bones and the internal structures of the paranasal sinuses. There are therefore many different presenting signs, including a unilateral nasal discharge, head shaking, exopthalmus (bulging of the eye), facial deformities and dyspnoea. It was agreed with both the owner and the insurance company that preventative minimally invasive surgery was in the horse’ best interest before these clinical signs became apparent.
The horse was operated on under a standing sedation (continuous rate infusion) and local anaesthetic, which included a maxillary nerve block. The frontal sinus was trephined and used as the endoscope portal. A smaller trephine into the caudal maxillary sinus was used as the instrument portal to remove the cyst.
The video below shows the surgical procedure, with the cyst attached to the ventral floor of the caudal maxillary sinus. Initially the fluid was drained from the cyst before the slightly mineralised wall of the cyst is removed piece by piece with rongeurs.
A foley catheter was sutured into the frontral sinus, and it was used to lavage the sinus the following day. The horse was then discharged from the hospital on a course of antibiotics and anti-inflammatories.
Both of the trephine sites healed very quickly with granulation tissue forming within 7-10 days to cover the holes in the skull. The prognosis following this procedure is excellent – with far quicker healing when the surgery is performed via ‘keyhole’ incisions as opposed to the elevated bone flaps, which are often required for larger cysts.
Download the Sinus Cyst video (161Mb)