Rupture of the gastrocnemius muscle at its distal musculotendinous junction: conservative treatment and outcomes in 11 dogs

CASE HISTORY

Medical records from three veterinary referral centres and a university veterinary teaching hospital in Australia and the USA were reviewed to identify dogs with a diagnosis of distal gastrocnemius musculotendinous junction rupture (DGMJR) that were treated without surgery between 2007 and 2020.

CLINICAL AND IMAGING FINDINGS

All dogs (n = 11) presented with unilateral, pelvic limb lameness and bruising, swelling or pain on palpation at the distal musculotendinous junction. The diagnosis was confirmed with ultrasound or MRI in six dogs; radiographs were used to excluded stifle and tarsus pathology in four dogs; and five dogs were diagnosed on physical examination findings.

TREATMENT AND OUTCOME

All dogs were managed conservatively, either with complete confinement alone (n = 10; median 9 weeks), external coaptation alone (n = 1), or a combination of both (n = 4). Sporting dogs (n = 7) were completely confined (median 22 weeks) for longer periods than companion dogs (n = 3; median 5 weeks).A good to excellent outcome was achieved for all cases in this cohort. The seven sporting dogs achieved an excellent outcome; returning to their previous level of sport, with complete resolution of lameness and recovery of a normal tibiotarsal stance. The four companion dogs achieved a good outcome; returning to their previous level of activity but with persistently increased tibiotarsal standing angle compared to the contralateral limb.

CLINICAL RELEVANCE

Conservative treatment represents a viable treatment option for dogs with a rupture of the gastrocnemius muscle at its distal musculotendinous junction.

Functional expression and cellular mRNA localization of a G protein-activated K+ inward rectifier isolated from rat brain

We have cloned by homology screening from a rat brain cDNA library a GIRK3-type (Kir 3.3) inwardly rectifying K+ channel subunit with high structural similarity to other subfamily members whose activity is thought to be controlled by receptor-stimulated G proteins. When heterologously expressed both in Xenopus oocytes and in mammalian COS-7 cells, rbGIRK3 subunits individually fail to form functional channels. In contrast, when coexpressed with other GIRK subunits, rbGIRK3 gives rise to prominent currents which are enhanced by the stimulation of coexpressed 5-HT1A receptors. In situ hybridizations show that of all GIRK subunits rbGIRK3 is most widely distributed and strongly expressed throughout the rat brain and thus may play an important role in central signal processing.