September 2016 Case Study – Boo Boo

September 2016 Case Study – Boo Boo

boo1Name:            Boo Boo

Age:               1 1/2 Years Old

Breed:            Domestic Short Hair Cat

Condition:       Bilateral Luxating Patella


Boo Boo has been attending the centre for Aquatic Treadmill Hydrotherapy following diagnosis of Bilateral Luxating Patella and Surgery to the Right Hind Limb.

The patella (kneecap) is a small bone that is positioned immediately above the tendon of insertion of the quadriceps muscle group onto the top of the tibia (shin). The patella acts as a fulcrum during normal extension of the knee joint. It glides up and down within a groove that forms the front of the knee joint. In some animals, the patella luxates (dislocates) out of this normal groove. The consequence of this luxation is an inability to properly extend the knee joint. As well as the lameness caused by the mechanical deficiency of the affected knee, there are varying degrees of pain and osteoathritis.

Patella luxation is a common condition. It affects mostly dogs (although cats can also be affected) and is more common in smaller dogs (although dogs of all sizes can be affected).

The age at onset of clinical signs is variable. Most animals start to show signs as puppies / kittens or young adults, although onset of signs in mature animals is also common. Animals with a “bow-legged” stance are more likely to be affected by patellar luxation. A characteristic “skipping” lameness is often seen, where animals will limp for a few steps and then quickly return to normal. Some animals will limp continuously and some animals affected by patella luxation in both knees will have a stiff, awkward gait with knees that do not extend properly.


This diagram indicates where the patella is located and the normal anatomy alongside a patella luxation.

As the patella moves in and out of the groove, it can wear holes in the cartilage of the patella itself and in the ridge that it rides over when it luxates. This causes pain and triggers a cascade of progressive osteoarthritis. Also, the abnormal pull of the quadriceps causes internal rotation of the tibia relative to the femur that can stress other structures within the knee, including the cranial cruciate ligament (CCL). The longer the patella spends outside its normal groove, the shallower the groove becomes.

Surgical treatments are recommended for animals with an intermittent or permanent lameness as a result of the patellar luxation. There are many surgical techniques; the primary aim is to restore normal alignment of the quadriceps muscle relative to the entire limb. This requires reshaping of the bones and reconstruction of soft tissues.

The most important component of the repair is to realign the insertion of the tendon spanning between the patella (kneecap) and tibia (shin bone). Because bones heal much more efficiently than tendons, the bone that this tendon is attached to is cut and moved to a more appropriate position. It is pinned back into place and the bone heals gradually over the following 4-8 weeks. Often wire is placed in addition to the pins so that the pull of the quadriceps muscle is effectively balanced by wire anchored to the tibia in the opposite direction.


This X-ray shows what Patella Luxation Surgey (Tibial Tuberosity Advancement) will look like.

Occasionally the pins require removal after surgery if they begin to interfere with the joint and range of motion.







Boo Boo first attended the centre in April 2016 where she had been for surgery on the right hind limb and was advised to build up the muscle mass prior to surgery on the left hind limb.


On this first session Boo Boo was assessed fully including muscle mass measurements, gait analysis, full palpation and discussion with the owners regarding at home care and daily routine.


The measurements on this first session were as follows:-


Limb Measurement
Left Fore 13cm
Right Fore 13cm
Left Hind 24cm
Right Hind 22cm


These measurements indicated some degree of muscle wastage in the right hind limb due to the recovery from surgery and the reduced use of this limb.

Boo Boo was on no medication at this time and was confined to the house at present following the advice given by the Veterinary Surgeon.

She was tentative to place the right hind limb and so was re distributing her weight through the left hind limb to reduce the pressure on the right hind.

Following the assessment it was decided that Boo Boo was suitable for Aquatic Treadmill Hydrotherapy and she was fitted with a harness and carried into the treadmill with the hydrotherapist.

Boo Boo was a little tense on the first session and so was held on the hydrotherapists lap until she started to relax before any session was started.

The water was initially filled to 4 inches and then increased to 7 inches and the speed from 0.1-0.4mph.

On the initial session she managed 3 sets of 30seconds to 1 minute being rested between again on the therapists lap.

After the first session Boo Boo started to relax and carry out her sessions well and seemed to enjoy the cuddles with the therapist and the towel dry at the end of the session. She carries out the sessions well in general although is not overly keen but she is happy enough to walk throughout.


Boo Boo walking during one of her sessions assisted by the Hydrotherapist.

After 10 sessions Boo Boo was re-assessed and her muscle mass measurements were as follows:-


Limb Measurement
Left Fore 14cm
Right Fore 14cm
Left Hind 25cm
Right Hind 24cm


These measurements indicated that Boo Boo had built up her muscle mass well and was using the right hind limb well now also.

Following on from this session, Boo Boo will be going for the surgery on the left hind limb and for the pin to be removed on the right hind limb so she will be away from hydrotherapy for a short time whilst she recovers from the surgery and the wounds heal.

Boo Boo will be returning to hydrotherapy once the Veterinary Surgeon is happy for her to continue.

We all wish Boo Boo the best with her surgery and recovery and look forward to welcoming her back to the centre for more treatment.