Delayed Pelvic Limb Use

[jabro30]

Aloha!

Looking for guidance concerning delayed use of a right hindlimb following post-op repair of a femoral fracture…

The dog in question is a 13-month old, male neutered Australian Shepherd who suffered a femoral fracture after falling out the back of a truck at the end of January. No neuro deficits noted. Nothing special noted in the surgery report, except that an arthrotomy in the stifle was done (not sure why).

Owner noted that “recovery” was uneventful and that they did their best in keeping him exercise restricted. Xrays were done at the 8-week mark (see attached) and surgeon said it was okay to return to normal activity (running on property, hard play with other dogs in households).

Looking at the 8-week rads, I assumed that callous formation was due to the dog’s age, as well as the potential for a third separate bony fragment to have been replaced, but not secured. Additionally, there appears a bit of radiolucent lines in the bone indicating the need for more healing. Other variables are the abnormal position of the patella (but the views looked a bit rotated) and the length of the plate.

I began seeing him about 15- weeks post-op for delayed continued delayed use of the limb. On initial exam, he was 2/5 lame at walk with weight-bearing lameness at stand. He was the definition of maldaptive pain and even light palpation elicited attempts to bite. We re-started on pharmaceuticals (Carprofen, Amantadine) which facilitated better handling and more ability to perform manual therapy, acupuncture, and photobiomodulation.

After working on all the regions with compensatory strain (hips, SIJ, lumbar), Karl’s the degree of Karl’s weight-bearing improved, as did functionality (much better ease with stairs, ability to jump, etc). However, at a stand, Karl always off-loaded weight from the surgical limb.

Recently, we tried to wean analgesics and Karl developed a worsening in gait (with more pain at the level of the stifle). Serial exam features have demonstrated reduced stifle flexion by about 15 degrees, moderately thickened/proliferative stifle, as well as crepitus-like sensation on the localized to the lateral aspect of the affected stifle. Not painful during passive ROM of the stifle and no instability appreciated. Some mild patella tendon thickening, with no pain on palpation.

Based on regression, I had the owners get repeat xrays to look at healing and while the implants do not demonstrate movement/changes, I am still concerned about the length of the plate and the position of the patella.

My concern is that we could do all the strengthening and postural re-training in the world, but if there is pain at the level of the implant that requires constant analgesia, that this would be a rate-limiting step. Possible that the plate is restricting normal caudal patella glide during flexion – any way to test his knowing that range of motion in flexion is indeed restricted? Am I too fixated on the implant?

Thank you!

[jabro30]

more rads attached

[lehughes]

Hey Jacob,

I don't think you're crazy to be worrying about the plate in this scenario. I think the key pieces of the history are that the dog is not sound without pain meds. I was trying to piece out for how long he was on the meds the second time before he was off and re-regressed. If it's wind-up pain, then yes, the dog likely needs to be on something longer than a typical regimen.

The lack of flexion could be impedance of patellar glide as you suggest. Or, he's still young, it could be a bit of a quads contracture as well.

The off loading in stance may very well be permanent - sort of like some TPLO dogs that never stand 100% (leg length discrepancy or just a different sensation to the other)... but you're right in that it should improve somewhat.

Okay, so to test, I would 1) palpate along the length of the implant to see if there is an area of pain, 2) try gliding the patella cranially and caudally in neutral (it's not a bit motion, but see what you can get, see if it's painful, compare to the other side) and 3) Try flexing the dog's stifle and then compressing the patella against the trochlear ridge in varying degrees of flexion - looking for pain. If you have pain with any of these, then I'd say most likely plate related.

There is no major harm in trying to rehab / get limb use up to a point in deciding whether the plate should be removed (i.e. bone is strong enough to hold on it's own). If the issue is a 'rub' or 'impedance' then exercise will flare it or have zero effect. If not, then improvements will be made. So this too is a bit of a test.

Best of luck with this one!

Cheers,

Laurie

[David Lane]

There are a certain number of cases where pain persists until the implant is removed, even if all looks well on radiographs. Given the distal location of the plate into the joint, I can totally buy into the idea that it is the source of pain. As LEH suggested above, do what you can to determine if there is focal tenderness, but sometimes explanting becomes a leap of faith effort - a procedure that is undertaken when all other possible causes of pain are eliminated (as much as one can), with no certainty if it will make a difference or not.

[jabro30]

Hey Team,

Thanks for the input, much appreciated.

Unfortunately, I have seen a bunch of quad contractures and based on feel of the muscle and active stifle ROM (can step over moderately Cavalettis without issue), would think pathology would be less of a possibility.

To add a bit more info concerning pharmaceuticals, the patient was on NSAID+Amantadine for 4 weeks prior to trying to trying to discontinue the Amantadine (at which point, clinical signs associated with pain began about 5-6 days after last dose).

Saw the patient earlier this week, at which time owner withdrew both meds for 48 hours prior to appointment (...on her accord) and worsening in gait/functionality. Found:

• pain is not localizable to the plate
• patella is actually now deviated a bit laterally; subjectively, I feel like there is less glide motion than normal (compared to contralateral patella) and no direct pain on manipulation or on compression
• mild-to-moderate stifle swelling
• stifle flexion reduced by about 15 degrees with end-range pain (not a "block" end feel...more like a "springy")

I feel like Dr. Lane summarized my sentiments that an explant is a leap of faith, but with all other factors accounted for, it is my next loggical recommendaiton and referred to surgeon for evaluation.

Will keep ya'll in the loop.

[David Lane]

With that additional information, low grade implant infection just jumped up a few levels on my differential rule out list.

[lehughes]

I totally defer to David's thoughts.
I just wanted to add another differential - in that it brought to mind a case from the past.
Vet-owned Boxer following a tight-rope repair... which seemed to anger what must have been an already brewing synovial cancer at the stifle joint.
David's thought is likely more on the money however!
Laurie