Orthopedic Surgery



Today I got to perform my first luxating patella surgical repair on a little dog.  Over the last 9 months of being a veterinarian, I have found that I really do prefer surgical cases to medicine cases.  Today was a treat.  In laymen's terms, a luxating patella repair is a major orthopedic surgery involving putting the the knee-cap back in place.  It involved a two-part procedure (for this specific case) including a trochlear wedge resection and a tibial tuberosity transposition.  Here's how the surgery "technically went"...later I'll re-cap it in understandable terms.

The Trochlear Wedge Recession.

A craniolateral skin incision 4 cm proximal to the patella was made. The incision was extended 2 cm below the tibial tuberosity. The subcutaneous tissue was incised and then the lateral retinaculum and joint capsule was incised to expose the joint. The articular cartilage of the trochlea was incised making a diamond shaped outline. An osteochondral wedge of bone and cartilage was removed following the outline. The two oblique planes that formed the free wedge intersected distally at the intercondylar notch and proximally at the dorsal edge of the trochlear articular cartilage. The osteochondreal wedge was removed and the recession in the trochlea was deepened by romoving bone from the sides of the newly created femoral groove. The wedge was also remodeled to allow it to sit deeper in the femoral groove. The depth was sufficient to house 50% of the patella. The patella was replaced and the stability was examined. The joint capsule was closed with 2-0 PDS, using a taper needle with a horizontal mattress suture pattern. The lateral retinaculum and tensor fascia lata was closed with 2-0 PDS in a simple interrupted pattern.

The Tibial Tuberosity Transposition.

A lateral parapatellar incision through the fascia lata was made and extended distally onto the tibial tuberosity below the joint line. The cranial tibialis muscle was reflected from the lateral tuberosity and tibial plateau to the level of the long digital extensor tendon. Sharp dissection was used to gain access to the deep surface of the patellar tendon for placement of the osteotome. Then at the level of the patella, a medial parapatellar incision was made through the fascia and distally through the periosteum of the tibial tuberosity. The osteotome was positioned beneath the patellar tendon 3 to 5 cm caudal to the cranial point of the tibial tuberosity and on the lateral side. A mallet was used to complete the osteotomy in a lateral to medial direction at two different sites. The medial side was released. The site of relocation was chosen. The tibial tuberosity was levered into position and stabilized with two 0.4 Kirschner wires directed caudally and slightly laterally. The caudal cortex was engaged but the pin did not exit the tibia caudally. The stability of the patella was checked.

The fibrous joint capsule, the cut edge of the fascia lata, and the subcutaneous tissues were sutured with 2-0 PDS in a simple interrupted pattern. The skin was sutured with 2-0 PDS suture in an intradermal subcuticular pattern. Tissue adhesive and surgical staples were placed on top for added reinforcement.

Post-Operative Care: Leash walking only for 6 weeks and then the patient should be slowly and gradually returned to normal activity.

In Laymen's Terms:

If you can imagine how painful it would be for your knee-cap to slip entirely to the inside of your leg, you can imagine the pain this llittle dog was in and the necessity of the surgery.  So for the procedure, the dog got his leg cut on the side next to his knee-cap.  The knee-cap was found.  Check.  The thigh bone was found.  Check.  A wedge was cut in the thigh bone like a slice of pizza.  The slice of pizza's crust on the bottom was partly removed.  Who would eat the crust and not the cheese?  Who knows.  But the smaller pizza slice was put back in place.  Stuff got sewn up.  Then the shin bone was cut into.  The pointy ridge on the shin bone that hurts when you scrape it on something was sliced under/undermined.  It was moved to the outside and pinned in place with little wires that look like the straight edge of a safety pin.  Stuff got sewn up again, skin glued, and stapled shut.  The dog's knee-cap got fixed.  And it was awesome.  And thank you to Fossum for the technique.