Laurie's Blogs.


Jun 2012

To Brace or Not to Brace?

There is always a hot debate on whether or not to brace an ACL-deficient knee or not.  Right up front, I will tell you that I am not a supporter of bracing dogs with cruciate tears – outside of unforeseen circumstances.  Here is what I found in regards to bracing in HUMAN literature.


Chew et al (2007) review:

o    Biomechanical studies by Wojtys and coworkers (1996) of ACL-deficient knees have shown decreased anterior tibia translation in braced knees under low loads, which was similar to daily activities. Beynnon and colleagues (2003) had concerns of anteroposterior shear when compressive loads were applied. Significant reduction of anteroposterior laxity was found during non-weight bearing and weight bearing, but not in transition between the two.

o    It has been shown that functional bracing may be effective in controlling anteroposterior translation in ACL-deficient knees under low loading conditions, but it may not be effective under high loading conditions that occur during athletic activities. Subjective improvements in knee stability and function are frequently reported, but objective evidence has yet to prove its effectiveness. The effectiveness of the functional brace in ACL-deficient knees depends heavily on appropriate rehabilitation programs


Birmingham et al (2008 Am J Sports Med) was a post-op use study and stated:

o    “We found no significant difference in self-reported disease-specificquality of life, ligament laxity, hop distance, or activitylevel at 1 and 2 years postoperatively in patients who underwentprimary ACL reconstruction and wore a functional knee braceor neoprene sleeve during return to physical activities. Confidenceintervals for group differences were narrow and excluded clinicallyimportant differences. Subgroup findings were minimal and inconsistentamong outcomes. Current evidence does not support the recommendationof using an ACL functional knee brace after ACL reconstruction”


Regarding ACL-reconstructed knees:

·         Beynnon et al 2002 found:

Application of a functional brace or neoprene sleeve to the ACL-deficieint limb does not improve the threshold to detection of passive knee motion; however, application of an elastic bandage to a knee with an ACL tear improves joint position sense.

·         Muellner and coworkers (1998) evaluated the effects of functional bracing compared with bandaging after ACL reconstruction and found no differences between the two groups in terms of strength and stability. Free range of motion was achieved significantly earlier in the bandaged group. The sensorimotor performance of the knee after ACL reconstruction has been studied by Wu and coworkers (2001), who found that bracing improved proprioception. The study involved comparison between the functional knee brace, placebo knee brace, and no brace after ACL reconstruction. Similar improvements in proprioception were found in the brace and placebo brace groups, suggesting that the apparent improvement was not attributable to the mechanical restraining action of the functional brace.

·         A 2007 systematic review of Level 1 evidence (Wright & Fetzer) found 12 RCTs. They found no evidence that pain, range of motion, graft stability, or protection from subsequent injury were affected by brace use post-operatively.


Back to ACL-deficient knees:

 Theoret & Lamontagne (2006) found:

  • Bracing significantly reduced total range of motion in the frontal and transverse planes (P<0.05). Muscle activity at heel-strike showed a consistent trend to increase for the hamstrings and decrease for the quadriceps under the braced condition when compared to the unbraced condition. Our findings indicate that bracing the ACLD knee alters the kinematics of the injured leg while running. Tendencies toward reductions in quadriceps and increases in hamstrings activity at heel-strike indicate that bracing might have resulted in added stability of the injured knee. The adaptations to bracing found in this preliminary study further support the potential mechanical and proprioceptive contributions of the functional knee brace to protect the ACLD knee.
  • However: Quadriceps weakness has been identified as common problem after ACL injury, and this weakness was persistent in patients with poor functioning knees.(Tagesson et al 2008).  So should we not be concerned about the reduced quadriceps functioning with bracing?



These finding were contrary to Ramsay et al (2003 Clinical Biomechanics) 

o    RESULTS: With brace, semitendinosus activity significantly decreased 17% prior to footstrike whereas bicep femoris significantly decreased 44% during A2, (P<0.05). Rectus femoris activity significantly increased 21% in A2 (P<0.05). No consistent reductions in anterior translations were evident.

o    What tends to be seen in ACL-D knees (Ciccotti et al 1994) is:


Table 1:  EMG Activity in Muscles of ACL-D Knees as Compared to Normal and Reconstructed Knees in Humans

Muscle Activation


Increase in vastus lateralis  activity at loading

Vastus lateralis resists internal rotation of the tibia

Increase in rectus femoris activity at pre-swing

This may indicate a decrease in knee flexion

Increase in biceps femoris activity at terminal swing

This may be to prevent anterior tibial translation with quadriceps contraction at loading

Increase in tibialis anterior activity at terminal stance

Tibialis anterior creates a dorsiflexion and inversion which also externally rotates the tibia (hence resisting internal rotation forces)

So, if semitendinosis and biceps femoris are decreased (in this study) with bracing, then there is a reduced ability to prevent anterior tibial translation...

  • All and all, we can see that these two studies (Theoret 2006 and Ramsey 2003) are contradictory...and neither of them relate to function.

Regarding mechanical stoppage of anterior translation:

  • Ramsey et al (2001 Clinical Biomechanics) found: “CONCLUSION: In this study, no consistent reductions in anterior tibial translations were observed as a function of the knee brace tested.”
  • So, we can gather from this that SOME braces may mechanically reduce anterior drawer while others do not. 
  • Do we have any idea what the dog stifle braces are doing for certain?


o    Swirtun et al (2005 Clin J Sports Med) showed:  “RESULTS: When using the brace the subjects in the brace group experienced less (P = 0.047) sense of instability, evaluated with visual analogue scale, than the control group. However, bracing had no effect on any of the variables in Knee Osteoarthritis Outcome Score or Cincinnati knee score and no effect on quadriceps or hamstring muscle peak torque. Subjectively, the brace group experienced a positive effect of the brace on rehabilitation. CONCLUSIONS: Nonoperated acute ACL-deficient patients experienced a positive effect of the brace regarding sense of instability and rehabilitation. However, these findings were not supported by objective outcomes.”


But if we go back to the tests comparing functional braces, placebo braces or neoprene braces or bandaging...  then we can gather that simply the contact around the knee assisted with proprioception (awareness of joint position)...not the kind or type of brace or any mechanical properties of said brace.  ( has a simplistic brace that would do nothing to stop the forces, but is a circumferential brace that goes over the back of the dog and will therefore stay ‘on’ the dog… and might just mimic bandaging or a neoprene sleeve.  Food for thought!)

  • So, maybe we bandage the canine stifles or simply instruct owners on proprioceptive inputting, which could even include petting, brushing and massage, and weight shifting with the therapist/owners hand circumferentially around the stifle – or both.
  • Would we get the same results with dogs and putting on a bandage/brace/etc or would that impact their desire to even use the limb effectively?  How do we measure joint kinaesthesia in dogs?  What are the EMG pattern comparisons in dogs with ACL-reconstruction, ACL-Deficiency, and ACL-D braced stifles? 


I have not found literature describing bracing’s ability to do the following:

·         Permit the injured limb to relax

·         Reduce fatigue in the injured limb

·         Provide mechanical protection against impact

·         Slow things down to allow muscles time to react and control 


I think we come down to the conclusion of Smith et al 2003 Arch Phys Med Rehabil: 

CONCLUSIONS: Brace use in this population did not consistently result in more favourable muscle firing patterns during the single-leg hop maneuver. Inter-individual responses to brace-use indicate the need for further research to investigate the multiple strategies that may exist to stabilize the ACL-deficient knee. In the meantime, functional knee brace use among ACL-deficient patients remains empirical.


These patients require a thorough rehab program, but we don’t tend to recommend bracing. I advocate for neuromuscular rehab instead. Either way, more research needs to be done to make definitive claims.


Those are my thoughts anyways!  Let me know what you think!  I’d love to hear what other people are finding to work.