MSD Manual

Please confirm that you are a health care professional

honeypot link

Overview of Lameness in Horses

By

Stephen B. Adams

, DVM, MS, DACVS, Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University

Last full review/revision Sep 2015 | Content last modified Oct 2015

Lameness is defined as an abnormal stance or gait caused by either a structural or a functional disorder of the locomotor system. The horse is either unwilling or unable to stand or move normally. Lameness is the most common cause of loss of use in horses. It can be caused by trauma, congenital or acquired disorders, infection, metabolic disorders, or nervous and circulatory system disease.

Lameness is not a disease per se but a clinical sign. It is a manifestation of pain, mechanical restrictions causing alteration of stance or gait, or neuromuscular disease. Pain is the most common cause of lameness in all horses. Mechanical lameness is best typified by complete upward fixation of the patella with its characteristic gait abnormality but can also be the result of fibrotic myopathy of the semitendinosus muscle or of restrictions caused by annular ligaments, adhesions, or severe fibrosis.

It is critical to correctly determine the cause of the lameness, because treatment varies greatly depending on the cause. For example, the mechanical lameness of complete upward fixation of the patella will not respond to analgesics, whereas lameness caused by pain often responds to systemic or local analgesics and anti-inflammatory drugs. Some causes of lameness produce very characteristic and classically described gaits. In fibrotic myopathy, a mechanical lameness, the affected limb is pulled back and down quickly before the end of the protraction phase, giving the impression that the foot “slaps down” on the ground. The signs are most obvious at the walk. In stringhalt, a neuromuscular disorder, the affected limb is hyperflexed during the cranial or swing phase, while the stepwise caudal jerking movement before foot contact does not occur. Unfortunately, many causes of lameness do not produce a characteristic gait abnormality, making diagnosis a challenge.

Pain-related lameness can be classified as weight bearing (supporting leg) or nonweight bearing (swinging leg) lameness. Although lameness is most often observed as a weight-bearing deficit, it may be composed of both. A supporting leg lameness is seen when the horse reduces the amount of time or reduces the amount of force applied to the weight-bearing limb. The most consistent and easily recognized clinical signs of lameness are the head nod associated with forelimb lameness and the sacral rise, also called a pelvic rise or hip hike, associated with hindlimb lameness. Hindlimb lameness should be assessed from the side as well as from behind, because this provides an opportunity to assess arc of foot flight, duration of protraction and retraction phases, length of weight-bearing phase, and the presence or absence of a sacral rise. Forelimb lameness should be observed from the front and side. Hindlimb and forelimb lameness in many horses will be accentuated when the horse is worked in a circle with the affected limb on the inside.

Factors that predispose horses to lameness include physical immaturity, which may occur in premature or dysmature foals, and training older foals before maturity. Other factors include preexisting developmental orthopedic disease (eg, osteochondrosis, flexural limb and angular limb deformities); poor conformation; improper hoof balance or shoeing; failure to adequately condition performance horses; monotonous repetitive stresses on bones, tendons, ligaments, and joints in performance horses; hard, slippery, or rocky surfaces upon which horses work; and extremely athletic activities. Inciting factors in lameness include direct or indirect trauma, fatigue resulting in incoordination of muscles (which often occurs in racehorses at the end of races), inflammation, infection, and failure to recognize early disease before it creates significant pain.

Lameness in one part of a limb often results in secondary soreness in another area of the same limb and may result in lameness of the contralateral forelimb or hindlimb from overuse due to compensation. The entire horse should be evaluated for secondary lameness even when the cause of the primary problem is obvious. Secondary lamenesses are very common in performance horses but may occur in all types of horses. A dramatic example of a secondary lameness occurs when biomechanical laminitis develops in the normal contralateral limb of a horse with limited weight bearing from a severe orthopedic problem causing shifting of weight from the injured limb to the normal limb.

OTHER TOPICS IN THIS CHAPTER
Lameness in Horses
Overview of Lameness in Horses
The Lameness Examination in Horses
Imaging Techniques in Equine Lameness
Arthroscopy in Equine Lameness
Regional Anesthesia in Equine Lameness
Disorders of the Foot in Horses
Osseous Cyst-like Lesions in the Distal Phalanx in Horses
Bruised Sole and Corns in Horses
Canker in Horses
Fracture of Navicular Bone in Horses
Fracture of Distal Phalanx in Horses
Keratoma in Horses
Laminitis in Horses
Navicular Disease in Horses
Pedal Osteitis in Horses
Puncture Wounds of the Foot in Horses
Pyramidal Disease in Horses
Quittor in Horses
Quarter Crack in Horses
Scratches in Horses
White Line Disease in Horses
Sheared Heels in Horses
Sidebone in Horses
Thrush in Horses
Disorders of the Pastern and Fetlock
Fractures of the First and Second Phalanx in Horses
Fractures of the Proximal Sesamoid Bones in Horses
Osteoarthritis of the Proximal Interphalangeal Joint in Horses
Palmar/Plantar Metacarpal/Metatarsal Nonadaptive Bone Remodeling in Horses
Sesamoiditis in Horses
Chronic Proliferative Synovitis in Horses
Digital Sheath Tenosynovitis in Horses
Disorders of the Metacarpus in Horses
Tendinitis in Horses
Suspensory Desmitis in Horses
Inferior Check Desmitis in Horses
Bucked Shins in Horses
Exostoses of the Second and Fourth Metacarpal Bones in Horses
Fractures of the Small Metacarpal (Splint) Bones in Horses
Fracture of the Third Metacarpal (Cannon) Bone in Horses
Disorders of the Carpus in Horses
Fracture of the Carpal Bones in Horses
Subchondral Bone Disease of the Third Carpal Bone in Horses
Tearing of the Medial Palmar Intercarpal Ligament in Horses
Osteoarthritis of the Carpus in Horses
Distal Radial Exostosis and Osteochondroma of the Distal Radius in Horses
Carpal Hygroma in Horses
Rupture of the Common Digital Extensor Tendon in Horses
Disorders of the Shoulder in Horses
Developmental Diseases of the Shoulder in Horses
Fractures of the Shoulder in Horses
Bicipital Bursitis in Horses
Infection of the Shoulder in Horses
Suprascapular Neuropathy in Horses
Osteoarthritis of the Shoulder in Horses
Disorders of the Elbow in Horses
Developmental Orthopedic Disease in the Elbow of Horses
Fractures of the Elbow in Horses
Osteoarthritis of the Elbow in Horses
Collateral Ligament Injury in the Elbow of Horses
Disorders of the Metatarsus in Horses
Bucked Shins/Dorsal Cortical Fractures of the Third Metatarsal Bone in Horses
Exostoses of the Metatarsal Bones in Horses
Diaphyseal Fracture of the Third Metatarsal Bone in Horses
Incomplete Longitudinal Fractures of the Plantar Aspect of the Third Metatarsal Bone in Horses
Focal Bone Reaction and Avulsion Fractures of the Third Metatarsal Bone in Horses
Fractures of the Second and Fourth Metatarsal Bones in Horses
Enostosis-like Lesions of the Third Metatarsal Bone in Horses
Disorders of the Tarsus in Horses
Failure of Ossification of the Distal Tarsal Bones in Horses
Osteoarthritis of the Distal Tarsal Joints in Horses
Osteoarthritis of the Talocalcaneal Joint in Horses
Osteoarthritis of the Tarsocrural Joint in Horses
Synovitis/Capsulitis of the Tarsocrural Joint in Horses
Osteochondrosis of the Tarsocrural Joint in Horses
Osteitis of the Calcaneus in Horses
Fractures of the Distal Tarsal Bones in Horses
Fracture of the Talus in Horses
Fracture of the Fibular Tarsal Bone (Calcaneus) in Horses
Fracture of the Lateral Malleolus of the Tibia in Horses
Tarsal Joint Luxation in Horses
Desmitis of the Collateral Ligaments of the Tarsus in Horses
Rupture of the Fibularis (Peroneus) Tertius in Horses
Stringhalt
Curb in Horses
Disorders of the Tarsal Sheath in Horses
False Thoroughpin in Horses
Luxation of the Superficial Digital Flexor Tendon from the Tuber Calcanei in Horses
Gastrocnemius Tendinitis in Horses
Calcaneal Bursitis in Horses
Capped Hock
Disorders of the Stifle in Horses
Osteochondrosis of the Stifle in Horses
Subchondral Cystic Lesions in Horses
Meniscus and Meniscal Ligament Injuries in Horses
Cranial and Caudal Cruciate Ligament Injuries in Horses
Collateral Ligament Injuries in Horses
Intermittent Upward Fixation of the Patella and Delayed Patella Release in Horses
Fragmentation of the Patella in Horses
Patellar Luxation in Horses
Others also read
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Test your knowledge
Lameness
The lameness examination is an important method to identify musculoskeletal abnormalities. Which of the following abnormalities is NOT observed during a physical and lameness exam? 
Become a Pro at using our website 

Also of Interest

Become a Pro at using our website 
TOP