Laurie's Blogs.

The question:

How do we deal with rehabbing dogs following Tightrope repairs for cranial cruciate ligament laxity?

For years, I had always told people that it matters very little WHICH technique was utilized to repair a CCL tear when it comes to post-op rehab.  “A post-op, is a post-op, is a post-op.  Set your goals and design your plan of care,” I would say.  However there is a bit of a conundrum with this advice when it comes to the new Tightrope repair.

The inventor of the procedure, Dr. Jimi Cook, DVM, PhD, DACVS, DACVSMR advocates for a very delayed introduction to rehab: 

“Yes, we advise against anything other than very controlled leash walking for at least the first 8 weeks and preferably 12 weeks after TR.  The reason is that extracapsular repairs, even one with bone-to-bone fixation and the highest implant strength and lowest creep like TR, are dependent on good periarticular fibrosis long term.  We need that periarticular fibrosis to develop at the best functional length and strength possible and “ligamentize” over time.  It takes at least 8 weeks for the initial collagen fibers to form, align and crosslink, so we want to protect them during this process.  Once that occurs, then we want them to remodel and strengthen well and build up muscle strength and ROM from there.  To lay people, I say “we can pretty readily get ROM and muscle mass back, but we can never get stability back if we do not achieve it during the initial healing period.”

So here are my thoughts on this:

I have only rehabbed a handful of tightropes, and heard reports from other therapists who have rehabbed them as well.  Our local surgeon is explicit about 5-min walks until 8 weeks.  Clients have found that their dogs needed a bit more than that (mentally)... but generally they are only up to 15 minutes by 8 weeks... which is still very much lower than my other post-op CCL-reconstruction patients at that stage.  The tightrope stifles tend to be a bit loose regardless of when they come to rehab or what stage they are at in rehab... (My findings – and those of others).

I feel that the laxity is likely resultant from a ‘wearing away’ of the entrance and exit holes of the tightrope rather than a stretching of the materials.  If it was just stretching of the materials AND tightrope material is supposed to be tougher than nylon - then why don’t the traditional extracaps end up all stretched out - as a regular thing?  The extracaps I see don’t tend to get ‘routinely’ stretch out during rehab!

While the ROM can likely come back at some point… the longer you wait, the more difficult it is!  Additionally the movement compensations that the animal adapts to can potentially put the ‘good’ leg/stifle at risk of injury, and result in other spinal dysfunctions as well.  And lastly, inadequate muscling and reflexive inhibition of muscles (secondary to injury & surgery) causes abnormal stresses and biomechanics at the joint.  The sooner you can get the muscles to help stabilize the joint, the better off the joint will be, as compared to relying on passive stability alone.  This, in combination with the dog that is, at 8 – 12 weeks post-op; mentally under-stimulated, physically deconditioned, socially deprived, and lacking in an ‘internal mechanism of surgical preservation’ (i.e. the dog won’t tell himself to start back to exercise slowly once his stifle stops hurting), a recipe for disaster!

So, how’s this:  I agree that with this technique the rehab should be VERY slow or started at a later date.  However, I’d chose a different technique if it were my dog.

As usual… tell me your thoughts and give me your feedback!

Laurie Edge-Hughes, BScPT, MAnimSt(Animal Physio), CAFCI, CCRT

Laurie@fourleg.com