Monitoring recovery post tibial tuberosity advancement surgery with Heyrex - Case Study

Animal details

Breed: Labrador retriever
Date of birth / age at commencement of study: 22nd February 2008 / 5 years
Sex:  Female (neutered)


This 5 year old Labrador retriever presented with a history of hind limb lameness following strenuous exercise.

Veterinary examination and diagnosis

On veterinary examination the cranial drawer test revealed laxity in both stifles. Radiographs were performed to screen for other contributing factors and minor hip dysplasia was observed. Rupture of both cranial cruciate ligaments was diagnosed. The decision was made to operate on the left  hindlimb first. Tibial tuberosity advancement surgery and the proceeding recovery were free of complications, and four months later surgery on the right hindlimb was scheduled.


The dog was admitted and surgery was performed on 7th February. A tibial tuberosity advancement was performed on her right hindlimb with no complications. The patient was discharged on 8th February with instructions for strict exercise restriction for a two week period. The dog was prescribed 50mg carprofen BID for 10 days, 50mg-100mg tramadol (depending on pain level) BID for 7 days and 750mg Cephalexin BID for 14 days to provide post operative analgesia and prophylactic antibacterial cover.

Monitoring response

On day two following surgery (9th February)  there was significant localised swelling at the operation site but the patient was already bearing weight on the limb. (Refer to Figure 2 for activity levels on that day.)

A post operative examination was performed two weeks after surgery on 19th February. The patient was observed walking and was fully weight bearing on the limb. Palpation of the stifle confirmed that the joint was stable. The skin incision had healed well and sutures were removed. At this stage exercise restrictions were relaxed somewhat and the amount of exercise the dog was permitted to undertake was increased. However, running, jumping and playing were still restricted. (Refer to Figure 3 for activity levels on a day following the adjustment of the exercise regimen.)

Remote monitoring with Heyrex was possible in between post operative checks  to assist in gauging the dog's ability to regain normal function and ensuring that pain was sufficiently controlled. In addition, it was possible to screen for excessive activity such as occurred on 28th February (refer to Figure 4 for activity levels on that day) and to advise the owner accordingly, thereby increasing compliance and decreasing the risk of surgical breakdown.


Monitoring with Heyrex prior to this dog's surgery meant that a baseline of the dog's usual levels of activity was established. It was then possible for the  dog's veterinarian to monitor:

  • Owner compliance with  post-operative exercise restriction protocols
  • The approximate pain status of the patient
  • The patient's ability to, and progress towards, regaining normal function
  • Recovery milestones such as finishing a prescribed course of analgesics or changes in exercise regimens

Fig 1:
 Daily activity totals from 3rd January to 3rd March show clearly the difference between pre- and post-surgery activity levels (surgery took place on 7th February). Comparison of post-surgery levels with pre-surgery levels allows the veterinarian to monitor compliance with exercise restriction instructions.


Figure 2: Reference to the daily activity graph for 9th February (two days post-surgery) reveals an activity profile that is consistent with cage rest. Note that the dog spent 73.68% of the day at rest and only 10.53% of the day vigorously active. There are long periods of inactivity with only one short burst of vigorous activity at 9pm.

Figure 3:
 Following the relaxation of some exercise restriction the dog shows a higher percentage of vigorous activity, in this case 31.25% but still spends the majoring of her day resting / confined.

Figure 4:
 Reference to this day, which stands out clearly on the long term view as having activity levels on a par with the dog's running mean, based on pre surgery levels, indicate the extent to which the dog engaged in vigorous activity. As such, the veterinarian is made aware of the dog being allowed to over exert itself and the subsequent risk of surgical breakdown.

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