Musculoskeletal Pathologies and Fractures

Musculoskeletal Pathologies Overview

• Familiarize with common musculoskeletal pathologies (fractures, degenerative disease, developmental disease, and soft tissue pathologies).

Fracture Classifications

• Fractures are classified based on their relation to the skin, the pattern of the fracture, and the bone fragments involved.

Classification of Fractures by Skin Relation

• Simple Fracture: All fracture edges remain within the skin.
• Compound Fracture: Part of the bone is exposed through a break in the skin.

Fracture Classifications by Cortex Involvement

• Incomplete Fracture: Only goes through one cortex of the bone.
• Complete Fracture: Goes through both cortices of the bone.

Fracture Classifications by Fragmentation

• Comminuted Fracture: Involves multiple bone fragments.
• Segmental Fracture: Two or more separate fractures are present in the same bone.

Fracture Classifications by Alignment

• Non-displaced Fracture: Fragments are still in alignment.
• Displaced Fracture: Fragments are out of alignment.

Fracture Patterns

• Transverse Fracture: A straight break across, perpendicular to the diaphysis (shaft) of the bone.
• Oblique Fracture: A diagonal break to the bone, can be short or long.
• Spiral Fracture: An oblique fracture that creates a spiral around the long axis, likely caused by a traumatic twisting motion.

Special Fracture Patterns

• Avulsion Fracture: Occurs at the point of soft tissue attachment.
• Salter Harris fractures: Involve the growth plate.

Types of Salter-Harris Fractures

• The different types are differentiated by the direction of the fracture line and whether it passes through or along the growth plate, epiphysis, or metaphysis.

Bucked Shins

• It is a type of dorsal metacarpal disease, characterized by painful periostitis (inflammation of the periosteum) on the dorsal aspect of the MCIII (cannon bone).
• The condition is painful to the touch and may involve a small, incomplete stress fracture.
• Usually results from high-strain cyclic fatigue (racing) on a continuously stressed bone.
• It is most commonly seen in young racing Thoroughbreds (around 2 years old).
• Treatment includes rest, anti-inflammatories, cold therapy, and reduced training.

Distal Splint Bone (MCII/IV) Fracture

• It is also known as "Splints” or "Popping a splint".
• It can occur due to direct trauma or suspensory desmitis.
• Inflammation associated with the fracture causes lameness, which often resolves after a few days of rest.
• Diagnosis is confirmed by radiography, but the suspensory ligament may also be examined with ultrasound.
• Treatment involves removing the fractured tip and any remaining abnormal bone.

Proximal Splint Bone Fracture

• The proximal part of the bone is responsible for bearing some weight and is involved in the carpal joint, requiring surgical intervention.
• Potential surgical interventions include removal of the bone fragment(s) or stabilization of the proximal part of the bone.

Cannon Bone (MCIII or MTIII) Fracture

• Typically is located at the distal articular surface, especially the lateral condyle.
• It is commonly seen in young racehorses due to repetitive strain.
• TBs tend to have this fracture more in MCIII (forelimb), while Standardbreds (SBs) have it equally in MTIII and MCIII.
• A noticeable sign is acute lameness after exercise with effusion in the fetlock joint.
• The preferred treatment is to repair the fracture with screws, ensuring they are flush to prevent abnormal joint wear.

Carpal Bone Fracture

• Usually are "chip fractures”, where the corner of a carpal bone is sheared off.
• It is almost always secondary to trauma from running at high speed.
• It usually occurs on the dorsal surface due to the shape of the carpal bones.
• A "Slab fracture" is a fracture that goes all the way through two articular surfaces ("complete").
• Management either involves removing the fractured piece if it's not very big, or reattaching it with screws if it's large.

Proximal Sesamoid Fracture

• A fracture that is classified based on its location within the bone
• Typically caused by overextension of the leg
• Usually associated with damage to the suspensory ligament
• Acute lameness with heat and swelling is associated with this issue.
• Increased pain when you flex the fetlock - can help to diagnose this issue.

Osteoarthritis Overview

• A review of joint components includes synovial fluid (clear, viscous, lubricates, and HA is the main component), Synovial membrane, and Articular cartilage.
• Surface between bones in contact with one another, that is avascular and aneural.
• Subchondral bone is the bone just deep to the calcified cartilage.
• It is more adaptable to lots of change in force than the adjacent trabecular bone.

Non-Infectious Osteoarthritis

• Is a leading cause of equine lameness, formerly known as Degenerative Joint Disease.
• Inflammation of the connective tissue damages the articular cartilage, due to age, wear, or abnormalities.
• Damaged articular cartilage cannot repair itself, leading to progressive damage/wear.
• Signs include heat, pain, swelling, stiffness, and crepitus in the affected joints.
• Various treatments are NSAIDs, steroids, injections, surgery, supplements, and alternative therapies.

Non-Infectious osteoarthritis

• It specifically affects the spine.
• It is characterized by bony proliferation on the ventral, ventrolateral, or lateral aspects.
• Tends to occur at T11-13.
• Not always painful.
• Can be related to age, injury/trauma, poorly fitting tack, or heredity.
• Treatment choices vary.

"Kissing Spine"

• This condition typically occurs between T10-18, potentially also between L1-6.
• It affects the dorsal part of the spinous processes, causing "Kissing" or overriding lesions.
• Proliferative bone forms in reaction to bone trauma & loss.
• The exact cause is unknown, but is likely due to poor conformation, riding technique, and core muscle engagement.
• It's found in racing TBs (Thoroughbreds), often without pain, but is rare and very painful in SBs (Saddlebreds).

Kissing Spine Grading System:

• Grade 1: narrowing of the interspinal space
• Grade 2: densification of the margins
• Grade 3: bone lysis adjacent to the margins
• Grade 4: severe remodeling

Infectious Osteoarthritis

• It is also referred to as Septic arthritis and is a bacterial infection of the joint causing inflammation.
• It may result from penetrating injuries, contaminated injections, surgery, or systemic infections.
• In foals, it's known as "navel ill,” where bacteria enters through the umbilicus.

Infectious Osteoarthritis: Diagnosing and Treatment

• It entails severe lameness & joint swelling.
• Associated with cloudy/thin synovial fluid where bacteria can be cultured.
• Systemic and local treatment with antibiotics is a must.
• The treatment plan is to flush out the dead & infectious material out of joint, and infuse the joint & nearby vessels with antimicrobials

Subchondral Bone Disease

• The term refers to the degeneration and necrosis of subchondral bone, often in the carpus & stifle.
• It can be caused by cyclic trauma that damages the subchondral bone.
• Can result in loss of innervation & blood supply and the eventual death of tissue.
• Lameness, effusion, and reduced performance are indicators, which often precedes slab fractures of carpal bones in racehorses.
• Diagnosis is confirmed by radiographs that reveal round or oval small lesions on articular surfaces.
• Treatment consists of removing necrotic tissue.

Developmental Orthopedic Conditions

• OCD (Osteochondritis Dissecans) is a common disease, only ~ ½ of horses have clinical signs of lameness.
• Cartilage/bone formation is disrupted in utero causing abnormal and weak cartilage.
• Creates cartilage & bone flaps & loose pieces that cause irritation, inflammation, and a subsequent arthritis
• Aggravated by rapid growth, diet, trauma &/or routine exercise.

Diagnosing OCD

• Typically confirmed by radiographic evidence of the fragment or Osteophytes
• Most common treatment is removal of the pieces.
• Usually seen in young horses capable to heal or be treated to have full careers.
• Shoulder OCD lesions can be hard to treat.

Developmental Orthopedic Condition Physitis

• It entails the swelling & inflammation around growth plate.
• Its affect long bones such as the tiba, radius, MCIII, PI, etc.
• Typically seen in fast-growing heavy foals around 306 months old.
• This is due to excessive load on immature growth plates plus a decreased bone and cartilage
• Joint has "boxy* appearance.
• There is a flaring at the growth plate associated with the swelling.
• Confirm with radiographs.

Physitis Treatment/Diagnosis:

• Reduce excess feeding to assist reducing growth rate
• Keep foal on soft surface with stall rest
• Supplement Calcium and Phosphorus with vitamin D supplementation
• NSAIDS can help reduce pain

Angular Limb Deformities

• Varus & Valgus are two typical angular limb deformities.
• It stems from many factors which is poor conformation, abnormal cartilage development, endochondral ossification, trauma, & hypothyroidisms.
• Typically these occur in the front limbs however they can occur in just one or all limbs.
• These conditions can cause lamess if harsh

Angular Limb Deformities: Diagnosis and Treatment

• To check for other potential abnormalities, a radiograph is taken
• Severe angular limb issues may need a cast/splint for a few weeks
• Goal is to stabilize the joint while encouraging light movement/exercise
• Highly severe cases will require corrective surgery ASAP

Flexural Limb Deformities

• Another name for this condition is, “contracted tendons
• Common in young foals and congenital
• Ca be cause by uterine malposition, fused joints, genetic defect
• This is most common in forelimbs
• Many times effects both legs however one is more severe
• Common in the fetlock and interphalangeal joints

Flexural Limb Deformities: Treatment and Prevention

• Conditions may cause toe abscess and physitis
• Causes a Chronic pain and inability to walk at all (using the affected joint as a knuckling joint)
• Treatment includes: splints/casts, high dosages of oxytetracycline, corrective hoof trimming, and possible surgery to cut flexor tendons
• Ensure that the mare is appropriately fed to increase health of gestational fetus

Common Digital Extensor Rupture

• Rupture is present when the foal is born and shortly after
• Often associated wit carpal or fetlock flexural deformities
• Typically in the forelimb
• Note a soft fluid swelling over the dorsolateral aspect of the carpus where there is an injured digital extensor
• Diagnosis and treatment
• Use ultrasounds to confirm condition
• Rest, heavy bandaging/splinting may prevent further injury
• If unrelated to other limb issues, prognosis is excellent

Soft Tissue Pathology

Tendonitis

• Inflammation of the tendon
• Can be either acute (trauma) or chronic (wear and tear)
• Generally is due to repetitive trauma, typically while racing
• In racehorses the SDF tendon is the most affected
• Barrel races are more likely to have DDF injuries

Tendonitis Diagnosis and Treatment

• If the case is neglected for too long it can become chornic, the tendons fibroses, and becomes overly thickened and hardened.
• Ultrasound is the best method to diagnose the the tissue damage.
• Rest and anti imflammatories is key!
• Treatment is much better if done early

Bowed Tendon

• Term for the visible swelling & “bowed” look of the tendon associated with tendonitis
• Can refer to either the SDF or DDF tendon
• Anywhere along the length of the tendon can occur

Soft Tissue Pathology: Suspensory Desmitis

• Means “inflammation of the ligament”
• Injury can occur in the proximal portion, body, or either branches of their respected tendon
• Localize the pain by blocking certain nerves
• Ultrasound is used to determine exact location and the severity of the desmitis of the tendon’

Soft Tissue Pathology Curb

• General name used to describe tissue swelling and inflammation
• Happens on the distal aspect of the taus
• Can be called tendinitis or tenosynovitis
• +/- Lamness
• Common in other breed and other athletes
• To diagnose use some general ultrasounds on the affected area to check whats going on

Tenosynovitis

• Inflammation of the tendon sheath
  • Protective layers of tendons are not longer useful; generally damage
• Happens common in flexor tendor sheaths and working horses
• No lamness if not secondary to infection, can be painful without open wound or laceration.
• Referred to as "Wind puffs"

Extensor Tendon Laceration

• • Trauma is NOT related to digital extensor tendon rupture*
• occurs because of tendon is unproted by being other than the skin or the limb
• More common in end limb
• When lacerated below it. The horse can not extend distal limb fully

Bursitis

• Its when the calcean and bicepitial busae are the too that are often damage
• Imflmation and damage of the busae can cause tendons
• May be related to associated tindinitis, injury or infection
• Use septic and agressilvy flushed
• Antibiotic therapy is key

###Peroneus Tertius Rupture

• Generally effects to reciprocal apparatus. That responds to tension of the stifle
• Causes severe hyperextension of the lower leg
• Commonly ruptures in the stifle
• Generally needs stall rest along with reduced exercise

Peroneus Tertius Rupture Signs

• Can move stifle and hock

• Cannot hold weight normally, with surrounding musles very flacid

• Definite lameness

• Charestic dimlping of the calcanea When hock is extended

• Muscle pathology*

• Exertional Rhabdomyolysis

• ""Tying up"" is a muscle fiber disease

• Generally no history of this disease

• Generally duce to exercise or training for a high physical animal

• causes anxiety and metabolic imbalsnces

Muscle Injury: Exertional Diagnosis and Treatment

• Diagnosis needs blood rest and possibly electron test to further
• They can gradually return but needs precautions
• Provide elxtrolystes
• Change diet plans
• new training techniques
• Hyperkalemic Periodic Paralysis (HYPP)
• Hyperkalemic Periodic Paralysis (HYPP)*
• Is a mutation in the sodium channel gene which is not genetic
• causes pores to leak with potassium
• Makes mucule overly excitable and contact at a rapidly high pace
• Hyperkalemic Periodic Muscle Diagnosis* -Muscle are diseased with genetics that were passed down with dominant autosomal that can affect the gene mutation -Qhs generally have the Impressive gene This gene has sixed a total of 2250 foals in a life time