Carpus, Tarsus, and Pes Flashcards
describe the skeletal anatomy of the carpus (2)
- 7 carpal bones held together by a variety of ligaments: intermedioradial carpal bone, ulnar carpal bone, accessory carpal bone, and 1st-4th carpal bones
- 3 levels of hinge joints:
-antebrachiocarpal: 90% of movement
-intercarpal
-carpometacarpal
describe the skeletal anatomy of the tarsus (2)
- 7 bones held together by a variety of ligaments: talus, calcaneus
-central and 4th tarsal bone
-1st, 2nd, and 3rd tarsal bone - 4 levels of hinge jointsL
-tibiotarsal: 90% of movement
-proximal intertarsal
-distal intertarsal
-tarsometatarsal
describe the ligament support of the carpus (5)
main support comes from the
1. joint capsule
2. flexor retinaculum- not reparable
3. palmar fibrocartilage- not reparable
4. in dogs, the medial collateral ligament has a straight and an oblique component
5. in cats, the medial collateral ligament only has a straight component, so carpal luxation can occur with disruption of the MCL alone!
describe the ligament support of the tarsus
all collateral ligaments have a long part that is taut in extension and a short part that is taut in flexion
it is important to assess mediolateral stability in both positions!
what are 7 common conditions of the carpus, tarsus, and pes?
- fractures
- carpal hyperextension injury
- traumatic antebrachiocarpal and tarsocrural luxation
- traumatic antebrachiocarpal and tarsocrural subluxation (collateral ligament injury)
- intertarsal and tarsometatarsal subluxation
- achilles tendon injury
- tarsal OCD
describe clinical evaluation of the carpus, tarsus, and pes
- pay attention to standing angle, compare to contralateral; look for dropped hocks and hyperextension
- swelling may localize an injury with accuracy because there is only sparse soft tissue coverage in these areas; compare to contralateral
- many injuries result in instability, so systemic and careful palpation is carried out with the joint stressed in mediolateral, dorsoplantar, and rotatory planes; compare to contralateral
- repeat exams when patient is sedated or anesthetized; may resist or be tense when awake!
describe diagnostic evaluation of carpus, tarsus, and pes
- orthogonal radiographs augmented with stress views, oblique views, and contralateral views
- CT is more sensitive than radiographs for fracture eval
- both/all may be required for accurate diagnosis!
describe carpal and tarsal fractures
- typically secondary to trauma and more common in active dogs
- often articular
describe 3 treatment options of carpal and tarsal fractures
- primary repair: pins, lag screws, plate and tension band wire, plate fixation
- arthrodesis: partial carpal/tarsal, pancarpal/pantarsal
- external coapatation not recommended; joint incongruity and OA can lead to persistent lameness
describe metacarpal and metatarsal fractures
- traditionally surgery is recommended if
more than 2 are fractured, MC3 and MC4 and fractured, marked displacement, base of MC II and V are fractures (don’t know criteria)
-can place small bone plates, little IM pins ALONE!!, of ESF but almost always protect with coaptation anyways - in reality: many cases can be managed successfully with coaptation
describe carpal hyperextension injuries (5) in general
- most common carpal inujury
- damage to flexor retinaculum and palmar fibrocartilage
- injury can occur at any joint level
- common is medium/large breed dogs
- typically involved jump/fall from height
describe acute versus chronic carpal hyperextension injuries
acute
1. non weight bearing
2. carpal swelling
3. pain on manipulation
chronic:
may present weight bearing with a hyperextended carpus
describe diagnostics of carpal hyperextension
stress radiographs are very important! look for areas of maximum angular change and compare to contralateral
describe treatment of carpal hyperextension injuries (3)
- conservative treatment is rarely successful
- surgical treatment is arthrodesis: partial or pancarpal because cannot repair the structures!, +/- postop copatation with palmar splint
- if sx not an option, can do orthotics; like a brace for exercise to get reasonable quality of life; can become comfortable despite instability but will develop arthritis likely
describe antebrachiocarpal luxation
see luxation lecture; remember is due to major trauma in dogs, and less severe trauma in cats
describe trasocrural luxation
see luxation lecture; just remember often a malleolar fracture in conjugation with luxation and shearing injuries are common
describe antebrachiocarpal/tarsocrural collateral ligament injury
- sprains of collateral ligaments can cause varyin degrees of lameness, often with lcoal soft tissue swelling, pain on palapation, but if just a sprain, instability is unlikely
- rupture of ligament leads to mediolateral instability
- diagnosis is usually confimred by joint space widening on stressed views
- palpation and radiographs of the unaffected limb can be helpful comparison
treatment options:
1. coaptation: if mild instability; splint bandage, immobilize tarsus/caprus for fibrosis to occur
2. surgical reconstruction with prosthethic ligament if more severe
3. arthrodesis
describe assessment of collateral ligament injury of antebrachiocarpal joint
- assess carefully for hyperextension
- isolated collateral ligament in carpus is uncommon! (need to rule out hyperextension)
describe assessment of collateral ligament injury of tarsus joint
- medial ligament disrupted more frequently than antebrachiocarpal
- not uncommon for both medial AND lateral structures to be damaged
- may have concurrent malleolar fracture (intra-articular, avulsion); so should provide anatomic reduction and rigid fixation (internal fixation with pin +/- tension band wire or lag screw)
-and/or shearing injury , often affecting the medial aspect of the joint; treatment options depend on underlying injuries (fractures, ligament disruption); primary concerns are delayed wound healing from instability and increased risk of infection
-trans-articular ESF may be useful for shearing injuries: provide stability, allow for wound management, but complications
-prognosis: good for weight bearing but will have decreased ROM and may require arthrodesis in the future
describe intertarsal/tarsometatarsal subluxation
- plantar instability most common and clinically significant; often secondary to trauma, concurrent fractures are common
- treatment:
-splinting typically not successful, partial tarsal arthrodesis recommended (intertarsal joints and tarsometatarsal joint, will not affect overall joint function that much bc low movement here)
describe plantar instability: achilles tendon injuries
- five components of achilles tendon (Good Sailors Build Good Ships)
-gastrocnemius
-SDFT
-combined tendon of: biceps femoris, gracilis, and semitendinosus - two common presentations:
-traumatic: penetrating wound, midsubstance tear, complete disruption
-atraumatic: (chronic tendinopathy slowly tears over time): medium/large active dogs, tear at calcaneal insertion, start as partial and can progress to full tear
describe traumatic rupture of the achilles tendon (5)
- acute severe lameness
- swelling, apin, bruising
- wound is not always present or obvious
- will have a palpable defect though (skin on skin between fingers, not tendon feeling)
- dropped hock due to inability to extend tarsus
describe atraumatic rupture of achilles tendon (4)
- acute/chronic lameness
- tendon thickening, often bilateral so won’t always have a comparison
- varying degrees of plantigrade stance
- clenched toes: partial disruption of intact SDFT; SDFT gets stretched and flexes digits
describe diagnostic imagng of achilles tendon rupture
- radiographs: swelling/thickening, avulsion fragment, entehsophyte formation, mineralization
- ultrasound: useful for ID specifics: site/level of injury, structures involved
describe treatment options of achilles tendon rupture (2)
dependent on severity and location
- low grade strain/partial rupture (LONG PROCESS):
-can try non surgical approach
-external support to keep in extension (splint/custom orthotic)
-exercise restriction strict for 4 weeks
-physical therapy to promote gradual tendon loading (UWTM)
-adjunctive therapies to stimulate healing: PRP, stem cells, US, laser, shock wave - complete or failed conservative management or traumatic tear:
surgical repair recommended: tendon suture pattern + immobilization
describe temporary immobilization of surgical repair of rupture of achilles tendon (3)
1, critical to protect the repair
2. different methods: cast/splint, calcaneotibial screw, ESF- all have complications
3. how long: 6-12 weeks, maximum 4 weeks of rigid stabilization, incrementally decrease amount of support (long recovery process)
what is the last resort of treatment of a ruptured achilles tendon?
pantarsal arthrodesis:
if tendon repair has failed or is not possible; relatively high risk of complications but can yield good to excellent outcomes
describe tarsal OCD; include location, clinical presentation, diagnosis, treatment options, and prognosis
- more common in dogs, on the medial or lateral trochlear ridges of talus (medial more common)
- clinical presentation:
-young, 4-8 months
-large and giant breed dogs
-lameness, pronounced effusion, crepitus - diagnosis:
-radiographs: oblique craniocaudal, flexed views)
-CT best - treatment options:
-medical (always)
-surgical (arthroscopy): flap removal + arthroplasty or total ankle replacement/arthrodesis (end stage OA) - prognosis: guarded
-dogs may improve with surgery
-many have residual/progressive lameness
