Page 8 - Clinical Connections - Autumn 2020

RVC RESEARCH STUDY VETERINARY SERVICES RVC.AC.UK Equine
CASE STUDY – STEM CELL TREATMENT OF
AN EQUINE TENDON
INJURY
Roger K.W. Smith, Professor of Equine MOrthopaedics
oonbeg Boy (‘Podge’), a 15-year-old Irish sports horse gelding used for eventing, had suffered an overstrain injury to his superficial digital flexor tendon in August
2018. He had developed a swelling in the mid-cannon region of his right forelimb two weeks prior to presentation at RVC’s Equine Referral Hospital. A brief trot showed him to be mildly lame on that leg and the right forelimb superficial digital flexor tendon was painful on palpation.
An ultrasound examination confirmed the presence of a core lesion in the superficial digital flexor tendon (Fig 1). Following discussions on the most appropriate treatments, it was elected to undertake stem cell treatment.
Bone marrow was obtained from the sternum the same day and immediately transferred to the RVC Stem Cell Laboratory,
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where the stem cells were grown. The RVC is a registered equine stem cell centre, authorised by Veterinary Medicines Directorate for the production and processing of equine stem cells for autologous treatment of horses.
Just over two weeks later the horse returned to have the stem cells injected under ultrasound guidance when the blood supply
to the lesion was pronounced (Fig 2). This is a fiddly process to ensure that the cells are accurately injected into the core lesion but this was achieved successfully as the air bubbles in the stem cell injection could be identified on ultrasound to be distributed only within the core lesion (Fig 2).
The limb was bandaged, and the horse returned home to undergo a graduated rehabilitation programme, beginning
with small amounts of walking in hand for five months before introducing trot work. The horse had its final re-examination at the RVC six months after implantation when the lesion had filled in well and the blood flow had reduced, indicating that inflammation had resolved and is taken as a positive sign (Fig 3).
The horse continued with its rehabilitation, guided by the referring veterinarian using regular ultrasound examinations, and returned to successful competition (albeit a bit delayed due to the coronavirus pandemic) in July 2020.
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Fig 1 – Ultrasound appearance of the superficial digital flexor tendon at
the time of presentation in the left and right forelimbs. Note the core lesion (approximately 14% of the cross-sectional area of the tendon; white arrows)
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Fig 2.– Ultrasound imaging of the implantation of stem cells. A shows the needle (white arrow) being inserted under ultrasound guidance
into the core lesion which now appears larger and darker. B shows
the marked blood flow in the tendon, shown by Doppler imaging on ultrasound. This is a natural feature of tendon injury but should reduce over time as the inflammation and heling progresses. C and D show the transverse (C) and longitudinal (D) images after implantation showing the accurate placement of the stem cell injection into the core lesion from the air bubbles in the solution that show up as very bright echoes on the images (white arrows).
For equine referrals, please call: 01707 666297
Email: equinehospital@rvc.ac.uk
Fig 3 – Ultrasound
appearance of the
tendon six months
after stem cell
treatment. The core
lesion has regained
its brightness B D (‘echogenicity’: A)
and its fibre pattern
(B) although the
architecture of
the tendon is not
completely restored and the outline of the core lesion is still visible (C; white arrows) although the blood blow has returned to normal (i.e. absent on Doppler imaging; C and D).
THE RVC'S STEM CELL LABORATORY
The RVC Stem Cell Laboratory is headed up by Dr Jayesh Dudhia and is one of only a handful of laboratories licensed by the Veterinary Medicines Directorate in the UK for the production of stem cells for clinical use on small animals as well as horses. The licensing ensures that all procedures and protocols are of the highest standard to ensure safety of patients which are treated with stem cells.
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Autumn 2020