Is Your Horse Off Behind?? Hindlimb Facts. Common Hindlimb Lameness. Diagnostic Techniques. Gait Analysis 3/21/2012

Transcription

1 Is Your Horse Off Behind?? Nathaniel A. White II DVM MS DACVS Jean Ellen Shehan Professor and Director Common Hindlimb Lameness Sacroiliac joint pain Hip Lameness Stifle Lameness Stress Fractures Hock Arthritis Suspensory Ligament Tenosynovitis Hock Fetlock Hindlimb Facts Muscles used for propulsion 40% of weight Feet have a higher hoof angle No stay apparatus Hock and stifle are connected so they can lock the limb for support Diagnostic Techniques Observation Palpation Heat Swelling Pain Flexion Lower limb Upper limb Nerve/Joint blocks Imaging Radiographs Ultrasound Scintigraphy MRI Thermography Gait Analysis Observe the lameness: Which leg? 1

2 Gait Analysis Gait Analysis Where is the Lameness? Where is the lameness? Joint Flexion Radiography 2

3 Scintigraphy Thermography Camera Detects infrared (heat energy) from skin High Field MRI High Field MRI Back Injuries Pain is often soreness due to lameness in the front or rear limbs Arthritis Dorsal spine interference Sacroiliac Pain Pain from the joints which attach the back bone to the pelvis Fibrous joint Bone and ligament pain Uneven gait and stiffness increased with horse under saddle. 3

4 Sacroiliac Pain Jumpers Bump Sacroiliac Joints Treatment includes injection of corticosteroids into and around the joint Hip Lameness Arthritis Rare and usually due to a fracture or luxation RX: Intra-articular treatments Luxation (dislocation) Rare Dislocation goes up shortening the leg Difficult to treat Pelvic Fractures Hip Luxation 4

5 Stifle Lameness Osteochondritis dessicans (OCD) Femoral bone cysts Meniscus damage Cartilage/subchondral bone injury Cruciate/collateral ligament rupture Patella Fracture Femoral OCD Defect in cartilage development under the patella Cartilage clefts and bone fragments Develop early 4-6 months but may not cause lameness until horse is placed in work Femoral OCD Femoral Trochlear OCD Treatment Early cases rest with possible healing Surgery to remove defective cartilage Surgery should be delayed until after 10 months of age Medial femoral condyle Fluid pressure expands a cartilage cleft Lining of the cyst is inflammatory causing lameness Bone Cysts 5

6 RX- Cortisone injections Surgery to remove the cyst lining Bone Cysts Subchondral Bone/Cartilage Injury Hardening of the subchondral bone Lack of spongy bone allows cracks form in the cartilage Subchondral bone pain Cartilage Defects Cartilage Damage Mensical Injuries Greater meniscus movement in extension More compression in the medial meniscus during extension of the legs Stifle Meniscal Injury Lameness Stifle effusion No radiographic changes Ultrasound examination may indicate a mensical tear 6

7 Ultrasound Diagnosis of Stifle Injury Meniscal Tear Medial Meniscal Tears Three grades of tears When the meniscal ligament is torn, the prognosis is poor Grade 2 Meniscal Tear Treatment Surgery Regenerative medicine Tibia Fractures Stress fractures Most common in race horses Malleolar fractures in the hock Lameness with hock enlargement Associated with trauma to limb Genetic tendency for OCD Lameness Fluid distention Hock OCD 7

8 Distal Tibial Ossicle Distal Tibial OCD Treatment Surgery Prognosis is excellent May retain some joint swelling Hock Arthritis (spavin) Inflammation of the lower hock joints Lower joints have minimum movement Arthritis can lead to bone proliferation and joint fusion Hock Inflammation Soreness or lameness Hip hiking-toe touching lameness Increased lameness after flexion Commonly in both hocks Hock Inflammation: RX NSAIDs Phenylbutazone Firocoxib (Equioxx) Hock injections Corticosteroids (Vetalog, Depomedrol) Hyaluronic acid Autogenous conditioned serum (IRAP) Adequan (Polysulfated Proteoglycan) Oral supplements Glucosamine Chondroitin Sulfate Avocado/Soybean Unsaponifiables Degenerative Joint Disease 8

9 Hock Degenerative Joint Disease Hock Joint Fusion (Arthrodesis) Hock Joint Fusion Surgical fusion Drilling with bone graft Chemical fusion 90% ethyl alcohol Direct injection Stall rest Fusion takes several months Pain may be improved before fusion Hock and stifle of foals are frequently involved Associated with infection of the umbilicus Bone infection is common and the source of bacteria Septic Arthritis Septic Arthritis Suspensory Desmopathy (Injury) Lameness onset is often acute or intermittent Lame in one leg; both involved. Localization with nerve blocks or scintigraphy Diagnosis made with ultrasound or MRI 9

10 Suspensory Desmitis Proximal Suspensory Desmitis: Bone response Suspensory Desmitis Rear Limb Suspensory Desmoplasty Ultrasound Guided Desmoplasty 10

11 Neurectomy Surgical Technique Custom fasciotome Dr.Fritz PreOP 3 months PostOP Andy Bathe- ACVS presentation; 2006 Proximal Suspensory Release What is the Lesion? Acute edema and fiber disruption Histocyte and fibroblastic response Collagen necrosis (necrobiosis) Ultrasonogram vs. Histology Proximal Suspensory Desmitis: Trichrome Stain 11

12 Suspensory Insertional Desmitis 11 months post operatively Suspensory Support Suspensory Support Maintain support for 1-2 months Can be combined with surgery or regenerative medicine Tenosynovitis Tarsal or digital sheath Excess fluid in the tendon sheath (wind puff) Tendon injury causes excess fluid Sheath Anatomy 12

13 Tenosynovitis due to tendon tearing Extensor Tendon Laceration 13