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