Bijoux the recipient of a Vet HQ first:
Bijoux, a 7-month-old cavalier crossed with a shih tzu was presented to us with an acute onset of lameness in the right hind limb after tripping down some wet stairs. On physical examination she had a mild laxity in her knee joint. Her patella (knee cap) was loose. She also resented having the stifle (knee) palpated and manipulated through all ranges of motion.
Lameness in the hind legs – and especially the knee can be related to either soft tissue injury or skeletal damage. As no obvious breaks were palpable on physical exam, we elected to trial conservative therapy for a few days to see if the lameness improved. Bijoux was sent home on non-steroidal anti-inflammatories (rimadyl), which provide analgesia and also reduce the inflammation around sites of injury. She was also to be rested for a week (no stairs and no running) with the view to recheck in a week if there was no improvement.
After a week, Bijoux returned with no real improvement. She had been rested thoroughly at home and she had been taking the medication as prescribed. As we had trialled the conservative options, it was time to conduct further work up via x-rays to ensure there was no other damage
Injuries of the stifle can be difficult to palpate and assess when the animal is conscious – as often they will tense the muscles around the knee and resist our manipulation. The two most common injuries or disease processes we see in the knee are medial luxating patella (or poor tracking of the knee cap in the groove) and also ruptured cranial (anterior) cruciate ligament.
Medial luxating patella is particularly common in small fluffy dogs and can be the result of an insufficiently deep groove for the patella to track in or a loose joint capsule caused by excessive rotation or trauma.
Cranial cruciate ligament rupture doesn’t discriminate between dogs and any dog can be affected. However, large breed dogs and overweight dogs are particularly prone due to the excess weight and pressure that is transmitted through the knee. Acute trauma is generally in dogs less than 4 years of age, and dogs with chronic lameness leading to rupture are generally between 5 and 7 years of age.
We need to anaesthetise or heavily sedate animals for radiographs to ensure correct positioning. Whenever we are looking at the knees we also look at the hips, as the femur (thigh bone) could be malformed thus affecting both the hips and the knees. The x-rays of Bijoux indicated increased laxity (movement) within the right hip and flattening of the femoral head. It also showed that there was laxity in the right knee with a medial tracking of the knee cap (Medial Luxating Patella) There were no signs of degenerative joint disease in either the left or right hips.
After much discussion we decided to perform a new technique on Bijoux. As she was only 6 months old and has at least 4 more months of growth potential our hypothesis was that if we placed her kneecap in the correct position this would modify the way she walked and help both her knee and her hip. This technique a soft tissue stabilisation has been discussed recently in the Veterinary Surgery Journals and early results are very favourable. The aim is not to have to perform more invasive orthopaedic surgery at a later age (+1year).
In as simple terminology as we can the ‘lateral imbrication’ works by taking a small strip of the connective fascia from the side of the knee, and then reconnecting the remaining tissue to tighten everything in like a belly tuck or gastric banding. The literature suggests that if this is done in younger dogs, the trochlear groove (or the groove where the knee cap sits and articulates) can become deeper from the pressure of the kneecap.
As we do not enter the joint, and no implants (screws or pins) are placed, the surgery time and the recovery are remarkably shorter than other more involved procedures when the stifle disease has progressed. As the joint capsule was tightened, there was some initial pain when Bijoux began walking again, but this was minimised with non-steroidal anti-inflammatories.
Bijoux was rested in a cage for 1 week before being allowed to return to small amount of controlled exercise (on lead) and so far the results are encouraging.
Only time will tell if we need to perform more significant surgery later on in her life. Lets hope not.