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Elbow Arthrodesis
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PA RT O N E
•
SURGICAL PROCEDURES FOR JOINT DISEASES
ELBOW
CHAPTER 10
Elbow Arthrodesis
INDICATIONS This procedure is indicated in animals with unreconstructable joint fractures, chronic elbow luxation or subluxation, or severe degenerative joint disease that is not responsive to medical treatment. OBJECTIVES • To fuse the bones of the humeroradial and humeroulnar joints in a functional position ANATOMIC CONSIDERATIONS The triceps muscle courses in a cranial proximal direction from its insertion on the olecranon, and crosses the humerus rather than running parallel to it. The radial nerve lies beneath the lateral head of the triceps near the distal third of the humerus. The ulnar nerve courses over the medial aspect of the elbow, caudal to the medial epicondyle, and an olecranon osteotomy aids joint exposure. A proximal ulnar ostectomy provides a flat surface for the plate. EQUIPMENT • Surgical pack, Senn retractors, Hohmann retractors, Gelpi retractors, periosteal elevator, oscillating saw, bone curette, self-centering plate-holding forceps, high-speed drill, burrs and wire driver, Kirschner wires, wire cutters, plating equipment PREPARATION AND POSITIONING Prepare the forelimb circumferentially from dorsal midline to carpus. Position the animal in lateral recumbency, with the affected limb elevated. Drape the limb out from a hanging position to allow maximal manipulation during surgery. A cancellous bone graft can be harvested from the ipsilateral proximal humerus. PROCEDURE Approach: Incise the skin and subcutaneous tissue on the caudal lateral aspect of the elbow from the distal one third of the humerus to the proximal one third of the ulna. Elevate the anconeus muscle from the olecranon. Osteotomize the olecranon process, and retract the triceps muscle proximally to expose the caudal surface of the distal humerus. Elevate the flexor carpi ulnaris and deep digital flexor muscles medially and the ulnaris lateralis muscle laterally to expose the proximal ulna. Reflect the origin of the flexor carpi ulnaris muscle to expose the trochlear notch. Incise the ulnaris lateralis, lateral collateral ligament, and joint capsule to expose the articular surfaces (Plate 10A). Alignment: Predetermine the cranial caudal angle for the elbow arthrodesis by observing the normal standing angle of the elbow in the individual patient (commonly 110 degrees) (Plate 10B).1,2 Stabilization: Remove the articular cartilage of the humeral condyle, radial head, and trochlear notch with a bone curette or high-speed burr, following the contours of the bone
ends. Perform an ostectomy of the proximal ulna to create a smooth surface for the plate (see Plate 10B). Temporarily fix the distal humeral condyle to the trochlear notch with a Kirschner wire (Plate 10C). Use an aluminum template to determine the contour of the caudal surfaces of the distal humerus and proximal ulna. Use the bending pliers and the torque irons to contour an appropriate-size bone plate (allowing at least four screws proximally and distally to the elbow) to match the aluminum template. Apply the plate by first placing screws through the proximal and distal plate holes. Place a lag screw through the plate and across the lateral portion of the humeral condyle into the radial head. Place a second lag screw through the plate across the ulna and into the medial portion of the humeral condyle (see Plate 10C). Fill the remaining plate holes. Screws placed through the ulna should penetrate the radius, if possible. Remove the temporary Kirschner wire. Reattach the osteotomized portion of the olecranon to the medial epicondyle with a lag screw (Plate 10D).1,2 Collect cancellous bone from the proximal humerus and place it around the ostectomy surfaces. Close the wound routinely. CAUTIONS The radial and ulnar nerves must be protected. All articular cartilage must be removed. Angular and rotational alignment of the limb must be checked carefully before the plate is secured. POSTOPERATIVE EVALUATION The axial alignment of the limb and the angle of the arthrodesis should be observed critically. Radiographs should be evaluated for limb alignment and implant placement. POSTOPERATIVE CARE A soft padded bandage should be placed to control bleeding and swelling. A lateral splint should be used for 6 weeks or until early radiographic evidence of bone bridging is observed. Radiographs should be repeated at 6-week intervals until bone healing occurs. The animal should be confined and activity should be limited to leash walks until bone healing is complete. The plate may be removed 6 to 9 months after bone healing if it causes soft tissue irritation. EXPECTED OUTCOME The bone usually heals in 12 to 18 weeks. Function of the treated limb can be awkward, and the animal may have trouble with stairs or with rough terrain.1 Amputation may offer better function.2 References 1. Johnson KA: Arthrodesis. In Olmstead ML (ed): Small Animal Orthopedics. St. Louis, Mosby, 1995. 2. Piermattei DL, Flo GL: The elbow joint. In Brinker, Piermattei, and Flo’s Handbook of Small Animal Orthopedics and Fracture Repair, 3rd ed. Philadelphia, WB Saunders, 1997.
PA RT O N E
•
SURGICAL PROCEDURES FOR JOINT DISEASES
ELBOW
CHAPTER 10
Elbow Arthrodesis
INDICATIONS This procedure is indicated in animals with unreconstructable joint fractures, chronic elbow luxation or subluxation, or severe degenerative joint disease that is not responsive to medical treatment. OBJECTIVES • To fuse the bones of the humeroradial and humeroulnar joints in a functional position ANATOMIC CONSIDERATIONS The triceps muscle courses in a cranial proximal direction from its insertion on the olecranon, and crosses the humerus rather than running parallel to it. The radial nerve lies beneath the lateral head of the triceps near the distal third of the humerus. The ulnar nerve courses over the medial aspect of the elbow, caudal to the medial epicondyle, and an olecranon osteotomy aids joint exposure. A proximal ulnar ostectomy provides a flat surface for the plate. EQUIPMENT • Surgical pack, Senn retractors, Hohmann retractors, Gelpi retractors, periosteal elevator, oscillating saw, bone curette, self-centering plate-holding forceps, high-speed drill, burrs and wire driver, Kirschner wires, wire cutters, plating equipment PREPARATION AND POSITIONING Prepare the forelimb circumferentially from dorsal midline to carpus. Position the animal in lateral recumbency, with the affected limb elevated. Drape the limb out from a hanging position to allow maximal manipulation during surgery. A cancellous bone graft can be harvested from the ipsilateral proximal humerus. PROCEDURE Approach: Incise the skin and subcutaneous tissue on the caudal lateral aspect of the elbow from the distal one third of the humerus to the proximal one third of the ulna. Elevate the anconeus muscle from the olecranon. Osteotomize the olecranon process, and retract the triceps muscle proximally to expose the caudal surface of the distal humerus. Elevate the flexor carpi ulnaris and deep digital flexor muscles medially and the ulnaris lateralis muscle laterally to expose the proximal ulna. Reflect the origin of the flexor carpi ulnaris muscle to expose the trochlear notch. Incise the ulnaris lateralis, lateral collateral ligament, and joint capsule to expose the articular surfaces (Plate 10A). Alignment: Predetermine the cranial caudal angle for the elbow arthrodesis by observing the normal standing angle of the elbow in the individual patient (commonly 110 degrees) (Plate 10B).1,2 Stabilization: Remove the articular cartilage of the humeral condyle, radial head, and trochlear notch with a bone curette or high-speed burr, following the contours of the bone
ends. Perform an ostectomy of the proximal ulna to create a smooth surface for the plate (see Plate 10B). Temporarily fix the distal humeral condyle to the trochlear notch with a Kirschner wire (Plate 10C). Use an aluminum template to determine the contour of the caudal surfaces of the distal humerus and proximal ulna. Use the bending pliers and the torque irons to contour an appropriate-size bone plate (allowing at least four screws proximally and distally to the elbow) to match the aluminum template. Apply the plate by first placing screws through the proximal and distal plate holes. Place a lag screw through the plate and across the lateral portion of the humeral condyle into the radial head. Place a second lag screw through the plate across the ulna and into the medial portion of the humeral condyle (see Plate 10C). Fill the remaining plate holes. Screws placed through the ulna should penetrate the radius, if possible. Remove the temporary Kirschner wire. Reattach the osteotomized portion of the olecranon to the medial epicondyle with a lag screw (Plate 10D).1,2 Collect cancellous bone from the proximal humerus and place it around the ostectomy surfaces. Close the wound routinely. CAUTIONS The radial and ulnar nerves must be protected. All articular cartilage must be removed. Angular and rotational alignment of the limb must be checked carefully before the plate is secured. POSTOPERATIVE EVALUATION The axial alignment of the limb and the angle of the arthrodesis should be observed critically. Radiographs should be evaluated for limb alignment and implant placement. POSTOPERATIVE CARE A soft padded bandage should be placed to control bleeding and swelling. A lateral splint should be used for 6 weeks or until early radiographic evidence of bone bridging is observed. Radiographs should be repeated at 6-week intervals until bone healing occurs. The animal should be confined and activity should be limited to leash walks until bone healing is complete. The plate may be removed 6 to 9 months after bone healing if it causes soft tissue irritation. EXPECTED OUTCOME The bone usually heals in 12 to 18 weeks. Function of the treated limb can be awkward, and the animal may have trouble with stairs or with rough terrain.1 Amputation may offer better function.2 References 1. Johnson KA: Arthrodesis. In Olmstead ML (ed): Small Animal Orthopedics. St. Louis, Mosby, 1995. 2. Piermattei DL, Flo GL: The elbow joint. In Brinker, Piermattei, and Flo’s Handbook of Small Animal Orthopedics and Fracture Repair, 3rd ed. Philadelphia, WB Saunders, 1997.