Arthroscopic Management of Joint Injuries and Intraarticular Fractures (Hip, Elbow, Carpus, Tarsus)
Professor, University of Veterinary and Pharmaceutical Sciences Brno, Department of Surgery and Orthopedics, Small Animal Clinic, Brno, Czech Republic
Arthroscopically assisted management of joint injuries and intraarticular fractures is a challenging procedure. It is technically demanding because a complexity of the instrumentation and the size and complexity of the joints in small animals. The majority of these cases are not routinely treated under arthroscopic assistance at present. On the other hand, arthroscopy has been successfully used to treat e.g., avulsion fractures of supraglenoid tubercle, lateral condylar fractures of the humerus, incomplete ossification of the humeral condyle, and avulsion fractures of cranial cruciate ligament. The indications for minimally invasive arthroscopic assisted surgery might be also some small fragment femoral head fractures, small fragment carpal and hock fractures. These cases might be managed by simple arthroscopic removal of the fragments.
Arthroscopy combined with surgical repair of injured joint structures using bone anchors is also becoming more popular. Bone anchors are used in orthopedic surgeries to anchor the suture material directly to the bone. Other indications are anchoring of different soft tissues such as ligaments, tendons and joint capsule. They are often clinically used in people to repair injuries of rotator cuffs, avulsions of distal bicipital tendon and cruciate ligament ruptures. In man, number of bone anchors has been successfully used; some of them can be used also in animals. Their main disadvantage is their high price. In veterinary orthopedic surgery, numbers of indications for use of bone anchors are known. Besides extracapsular CCL rupture repair, anchors can be used in following indications: reconstruction of collateral ligaments in elbow, stifle and tarsal joints, stabilization of hip luxation, shoulder instability (rupture of glenohumeral ligaments), and fixation of avulsion fractures.
Lateral humeral condylar fractures are common intraarticular fractures in dogs. They are routinely repaired using open fracture reduction and fixation, or fluoroscopically guided closed reduction. Minimally invasive arthroscopy might be used in closed management of this articular fractures. Arthroscopy of the elbow can be also used to diagnose and treat incomplete ossification of the humeral condyle.
Two types of intraarticular femoral head fractures are seen associated with coxofemoral dislocation in mature dogs. Each type presents a challenge to veterinary surgeon to achieve a satisfactory outcome. The more common type involves avulsion of a small portion of the femoral head, which is normally attached to the round ligament. The fragment is too small to be adequately stabilized and its presence may result in failure of attempts at treatment of the dislocated hip by closed reduction. Excision of the fragment is indicated in this case. This procedure can be done arthroscopically. The second, less common type, is when dislocation of the hip is associated with a much larger saggital fracture through the femoral head. If the fragment is larger than one-quarter of the femoral head, then the opportunity exists to reduce and stabilize the fracture with lag screws or with a combination of a lag screw and a small pin at the time of open reduction of the hip.
The carpus and tarsus are complex joints and present diagnostic and therapeutic challenges when injured. Instability and/or displaced intraarticular fractures lead to degenerative joint disease and chronic lameness with crippling consequences for the animal. In decision making in carpal injuries treatment, the surgeon should weigh up the type of joint instability and character of the trauma. In such cases, there anatomic reposition and rigid stabilization of articular fracture and/or reconstruction of injured ligaments is possible, the surgeon should attempt to restore the joint function choosing the reconstructive surgery. Carpal and tarsal injuries are commonly caused either falling or jumping from a height. An animal can sustain these injuries also in a road traffic accident. Any age or breed and either gender of dog or cat may be affected. Carpal and tarsal injuries may consist of fractures, ligamentous injuries, and various combinations. The list of traumatic conditions of the carpus might be extended and includes: luxation/subluxation of the antebrachiocarpal joint, luxation of the radial carpal bone, fracture of the radial carpal bone, fracture of the accessory carpal bone, subluxation of the accessory carpal bone, fracture of the ulnar and numbered carpal bones, middle carpal luxation/subluxation, carpal hyperextension and shearing injury of the carpus. The most often seen, and therefore in practice the most frequently treated, carpal injuries are: antebrachiocarpal subluxation (with medial joint instability due to the injury of the radial collaterals), carpal hyperextension and shearing injury of the carpus. Regarding medial antebrachiocarpal subluxation the most common affected ligaments in are the radial collaterals, resulting in medial instability and valgus deformity of the foot. The medial carpal instability may be congenital ("carpal dysplasia") or acquired (injury).
Arthroscopy of the carpal and tarsal joints can be used as mini-invasive method to diagnose the extent of intraarticular joint structure damage in traumatic cases or document possible congenital anomalies. Recently, the reconstruction of the medial collateral ligaments is also possible using a bone suture achor. This method of the treatment will be presented in the meeting lecture in the above mentioned case of congenital carpal instability and tarsal small fragment fracture/ligament injury in dogs.
Proper case selection is very important regarding to good prognosis in arthroscopically managed joint injuries and intraarticular fractures.
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