Fibrotic myopathy refers to a chronic, recurring disease (Laksito et al., 2011) most commonly diagnosed in male German Shepherd dogs aged between three and seven (Zink and Van Dyke, 2018). It predominantly affects m. Gracilis but the hamstring groups may also be involved (Steiss, 2002). The condition is characteristic by progressive fibrotic tissue in distal muscle belly. Affected dogs typically demonstrate shortened stride, lameness (unilateral or bilateral), restricted stifle extension and internal rotation of phalanges and stifle.
The patient in this case study is a 6.5 year old male retired police German Shepherd, suffering from bilateral fibrotic myopathy in his m. Gracilis. He is currently on no medication and exercises for 20 minutes three times a day. Danny showed no signs of pain and is currently coping well. The long-term goals for this case were to improve gait, prevent further secondary compensations and decrease progression of the disease.
During dynamic assessment, Danny demonstrated all of the previously described features associate with this disease (Lewis et al., 1997). Considering anatomical location and function of m. Gracilis, its contracture causes medial rotation of the stifle when the limb moves forward, which was more prominent in Danny's right hindlimb. A palpable contraction was located along the muscle belly of m. Gracilis bilaterally (1cm x 5cm). This may explain physical restrictions of stifle extension and hock flexion found bilaterally on range of motion assessment. Due to the locomotor deficits, secondary compensations were identified. Mild fasciculations palpable along the thoraco-lumbar region may be associated with kyphotic posture. The latter may have resulted from an increased lumbar flexion as a compensation for lack of hindlimb protraction. Furthermore, cranial loading may contribute to the mild atrophy of the hind end and hypertonicity of dorsal neck and shoulder musculature due to higher demands on these structures.
Main Findings
Narrow based at the front and behind
Elbows rotated internally
Reduced muscle mass behind
Cranially loading
Cow hocked posture
Hind digits laterally rotated
Kyphosis in lumbar region
Carpal flicking
Elbows in during stance, out during swing phase more at trot
Reduced protraction of hindlimbs R>L
Hindlimb circumduction
Stifle in hock out at swing
Palpation
Hypertonic dorsal neck and scapula bilaterally
Less developed supraspinatus
TL fasciculations
Atrophy of biceps femoris
Hypertonic m. Gracilis R>L with 5cm x 1cm fibrosis bilaterally
Hypertonic quads bilaterally
Hypotonic hamstrings bilaterally
In session treatment
Laser to TL trigger points (48 J/cm2, 700-10kHz)
Deep effleurage and wringing to dorsal neck and scapular musculature (15 min)
Heat to quadriceps bilaterally (15 mins each side)
Cross fiber friction to fibrotic tissue in gracilis bilaterally (2 mins each side)
US to fibrotic tissue 1x5cm (0.8cm2/W on continuous mode, 5min, 3MHz head)
Stretching (gentle protraction and abduction to both hindlimbs)
Underwater Treadmill (400 water height, 2.3 speed, 5 sets of 40-50s)
Home remedial exercises were prescribed to improve mild hindlimb atrophy, maintain range of motion and slow the progression of the disease.
References
Laksito, M., Chambers, B., Hodge, P., Milne, M., Yates, G. (2011) Fibrotic myopathy of the iliopsoas muscle in a dog. Australian Veterinary Journal. 89(4), 117–121.
Lewis, D., Shelton, G., Piras, A., Dee, J., Robins, G., Herron, A., Fries, C., Ginn, P., Hulse, D., Simpson, D., Allen, D. (1997) Gracilis or semitendinosus myopathy in 18 dogs. Journal of the American Animal Hospital Association. 33(2), 177–188.
Steiss, J.E. (2002) Muscle disorders and rehabilitation in canine athletes. The Veterinary Clinics of North America. Small Animal Practice. 32(1), 267–285.
Zink, C., Van Dyke, J.B. (2018) Canine Sport Medicine and Rehabilitation. 2nd ed. Wiley-Blackwell.
Picture retrieved from the Wix.com library.
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