Proximal Suspensory Ligament Desmitis

Proximal Suspensory
Ligament Desmitis
Luke Bass, DVM, MS
Signalment
9 yr old QH gelding
Function: Barrel racing
(nationwide)
History
Forelimb fetlock joint injections, chiropractic adjustments, and acupuncture
5/055/05- LH lameness (2+/5) blocked to TMT joint
RadsRads- No Significant findings
Stall rest and NSAID
6/05 – Chronic LH lameness
Nuclear Scintigraphy
DIT & TMT injected
4/064/06- RH lameness
Chiropractor adjustment & acupuncture
History
5/06 - LH lameness (2/5), + flexions, LH fetlock joint block
(70%)
LH fetlock injected
7/067/06- Lameness unchanged, LH fetlock U/S
SSL & OSL fiber disruption
8/068/06- ESWT - LH fetlock
8/068/06- LH lameness - 70% improvement with fetlock block
Diagnostic arthroscopy
History
1010-12/06 - Chiropractor adjustment, acupuncture
2/072/07- Bilateral lameness; moderate OA changes
Both hocks were medicated
2/072/07- Chronic LH lameness, + flexions
Proximal suspensory block
U/S - enthesiophyte @ origin, suggested MRI
Ultrasound
•Mild desmitis- Origin of the LH SL
•Mild enthesopathy- Origin of the LH SL
MRI and Surgical treatment
LHLH- Acute desmitisdesmitis- thickening, focal bony resorption at that
origin on MT3, and fluid in origin MT3 & MT4
RHRH- Chronic desmitisdesmitis- Thickened, severe scarring (scout images)
DecisionDecision- Bilateral plantar fasciotomy and neurectomy
MRI
Moderate enlargement – Origin of SL
Scarring to SL - Previous injury
MRI
Mild degenerative LH SL
Acute PSLD in LH
Tenosynovitis – RH tendon sheath
Chronic PSLD in RH
Forelimb Proximal SL Desmitis
4-12 cm DACB
Acute casescases- Pain and swelling in region
Chronic casescases- No palpable abnormalities
Positive distal limb flexionflexion- 50% of cases
Lameness accentuated on circle, extended trot
Foot imbalance – predisposing factor
Perineural Anesthesia
Lateral palmar nerve
- Medial and lateral
palmar metacarpal nerves
Ensures that carpal joints
are not inadvertantly injected
Palmar outpouching of CMC
joint > TMT joint
Hindlimb Proximal SL Desmitis
2-10 cm distal to TMT joint
Pain on palpation of proximal SL (acute)
Persistent lameness post rest
Hock flexionflexion- Accentuates lameness (85%)
Infiltration of anesthetic – Origin of SL
- Possible diffusion to TMT joint
Conformational abnormalities - (21%)
Perineural Anesthesia
Subtarsal nerve block
- 12.5% - TMT joint
- 50% - Tarsal sheath
Deep branch of lateral
plantar nerve
- 0% - TMT joint
- 12.5% - Tarsal sheath
Compartment Syndrome
Enlargement of SL – pressure to MT bones, plantar
MT nerves
Persistent pain and lameness
Early diagnosis and therapy to reduce size and
minimize inflammation
Current opinions refute this as 1°
1° problem
- Ongoing neuritis due to inflammation
Compensatory Desmitis
Ipsilateral forelimb w/ 1° foot lameness
Contralateral fore/hind - overload injury
Forelimb ipsilateral to 1° hind lameness - pacers
Contralateral forelimb (LH, RF) - trotters
Differential Diagnosis
Middle carpal joint pain- young TBs
DJD of middle carpal joint
Palmar cortical fatigue fractures- MC3
Avulsion fractures- origin of SL
TMT pain
Primary stress reactions of MT3
Radiographic Findings
Sclerosis of MC3, lateral MT3 - DP view
Enthesiophyte formation, subsub-cortical
sclerosis – Lateral view
Hindlimb > Forelimb
R/O avulsion fx MC3/MT3
Changes – rare in acute cases
Ultrasonographic Findings
Enlargement of the suspensory ligament
Poor definition of dorsal margin
Central core lesion
Larger area of diffuse hypoechogenicity
Focal demineralization
Examination of contralateral limb
Nuclear Scintigraphy
Unnecessary for diagnosis
Bone turnover at insertion of SL
No uptake
Abnormal uptake w/ no U/S changes
MRI Findings
Enlargement/abnormal high signal intensity in
ligament
Bone injury -Fluid in bone at insertion site
Comparison to contralateral limb – images side
to side
MRI Findings
Axial PD images
High signal in PSL
Axial STIR images
High signal in MT3
PSLD Therapy
Severity of lesions
Level of competition
Urgency of upcoming competition
Financial contraints
Recurrence of problem
Prognosis for forelimb > hindlimb
PSLD Therapy
Stall rest and support bandages w/ slow return
to exercise (forelimb > hindlimb)
Corticosteroid & PSGAG therapy
Shockwave therapy - 3 treatments
PSLD Therapy
Bone marrow injection
A-cell vs stem cell injection
Internal blister
Shoeing- Support fetlock w/o raising heel
Hindlimb PSLD Therapy
Fasciotomy w/ Neurectomy (Compartment Syn)
Desmoplasty (surgical splitting)
Tibial neurectomy
Prognosis – Guarded to resume athletic function
Failure to recognize lameness in early stage of
injury
Case Update
Chronic bilateral hindlimb lameness
History of hock injections
Radiographs
Ultrasound
Nuc Scan
MRI
Surgical Therapy
Fasciotomy with Neurectomy
Deep br. of lateral plantar nerve
Releases compartment pressure of SL
Postoperative Care
Phenylbutazone - (10 days)
Stall rest – 2 weeks
Introduce hand walking – increase slowly over 8
weeks
Re-check lameness ± U/S (8 weeks)
Total of 4-6 months until return to full athletic
function
Re-check Exam
7 wks - 3/5 LH, 1+/5 RH
15 wks - 1+/5 LH, 1/5 RH
Chiropractor adjustment and acupuncture
Recheck U/S, small paddock
17 wks (7/10)- No lameness, re-check U/S,
increase exercise- over next 2 months
9/07- 6 month re-check scheduled
References
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Auer & Stick, Equine Surgery, 3rd Ed. Saunders, p.1106p.1106-7.
Dyson, S.J., et al. Suspensory Ligament Desmitis. Vet Clinics of NA, 11:
177177-215, 1995.
Hewes, CA, White, NA. Outcome of desmoplasty and fasciotomy for
desmitis involving the origin of the suspensory ligament in horses:
horses: 27 cases
(1995(1995-2004), JAVMA, 229: 407407-412, 2006.
Stashak, T.S, Adams Lameness in Horses, 5th Ed., p.622p.622-623.
Bathe, A.P. Current thoughts on the pathogenesis of hindlimb proximal
proximal
suspensory desmitis. 13th ESVOT Congress: 169, 2006.
Dyson, S.J. Proximal suspensory desmitis in the forelimb and the hindlimb.
AAEP Proceedings:137Proceedings:137-142, 2000.
Schneider, R.K., Sampson, S.S., and Gavin, P.R. MRI evaluation of
of horses
with lameness problems. AAEP Proceedings: 2121-34 , 2005.
Gayle, J.M., Redding, W.R. Comparison of diagnostic anaesthetic
techniques of the proximal plantar metatarsus in the horse. EVE, 5/07, p.
222222-224.
Questions