Tenoscopy - Equine Flexor Tendon Sheath

EQUINE TENOSCOPY:

Dane M. Tatarniuk, DVM

November 13, 2014

Non-Septic Tenosynovitis

Anatomy

Digital Flexor Tendon Sheath (DFTS) Synovial fluid space, encompasses flexor

tendons

Identical between fore & hindlimbs

Length Proximal:

Junction of middle & distal 1/3rd of cannon bone

Distal:

Dorsally ‘T-ligament’ Barrier from navicular bursa

Palmar/Plantar Reflection of sheath wall on DDFT

Anatomy

Dorsal surface:

Branches of suspensory ligament

Proximal Scutum

(sesamoid bones & inter-sesamoidean ligament)

Distal sesamoidean ligaments

Palmar/Plantar scutum of proximal inter-phalangeal joint

Palmar/Plantar recess of distal inter-phalangeal joint

Anatomy

Palmar / Plantar Annular Ligament

Fetlock canal Maintains palmar /

plantar stability

Horizontal fibers

Level of the proximal sesamoid bones

Abaxial attachment

Blends with collateral sesamoidean ligament

Anatomy

Palmar / Plantar Digital

Annular Ligament

Over palmar/plantar

pastern

Quadrilateral

‘X’ shaped

Attach to the proximal &

distal abaxial eminences

of the first phalanx

Anatomy

Manica flexoria

“Sleeve”

Extension of the SDFT, wraps around

the DDFT

Level of the fetlock joint

Proximally

Continuous with digital flexor tendon

sheath

Distally

Extends to level of palmar/plantar

annular ligament

Function

Maintain tendon alignment within DFTS

Anatomy

Distal Manica Flexoria

Present at the level of the proximal phalanx

Anatomy

Vinculae

Present below the level of the proximal phalanx

Attach the DDFT to the DFTS

Tenoscopy Technique

Positioning

Predominately lateral recumbancy

Bilateral

Dorsal recumbancy (Smith, 2006)

Lateral recumbancy, medial approach to second limb

(Findley, 2012)

Tenoscopy Technique

Tourniquet

Applied to mid-cannon bone region

Benefits Decreased hemorrhage

Chronic tenosynovitis

Increased intrathecal pressure

Cons

Can reduce flexion/extension manipulation of the flexor tendons

Tenoscopy Technique

Thecal-centesis

4 standard approachs for distension:

(Jordana 2014)

Proximal

Approach

Palmar Axial

SesamoideanBase of Proximal

Sesamoid

Distal Palmar

Pastern

Tenoscopy Technique

Tenoscope Portal

Distal Sesamoidean

Between Palmar Annular Ligament & Palmar Digital

Annular Ligament

Immediately palmar to neurovascular bundle (1-2cm)

Tenoscopy Technique

Instrument Portal

Advance scope between SDFT

and PAL proximally

Use trans-illumination & needle

Surgical Disorders

Etiology of ‘non-septic tenosynovitis’

Proximal Annular Ligament Desmitis Dik 1991

DFTS rupture Dyson 1995

Longitudinal tears of DDFT or SDFT Wright 2003

Manica flexoria tears Wright 1999

Complex Tenosynovitis Fortier 1999

Proximal Digital Annular Ligament

Desmitis

Schramme

2003

Literature

Ultrasound n = 97 cases

Synovial fluid between superficial digital flexor tendon & proximal annular ligament Present = No constriction of

PAL on fetlock canal

Longitudinal tears on U/S Irregular borders

Hypoechoic foci

Echogenic masses

Diagnostic Imaging

Ultrasound 97/101

DFTS Effusion 100% (97/97)

Thickened mesotendon 48% (47/97)

Constricted PAL 36% (35/97)

Thickened tissue palmar

SDFT

62% (62/97)

Longitudinal tears 76% (74/97)

Diagnostic Imaging

Ultrasound vs. Surgery Longitudinal Tears

Sensitivity 63%

Specificity 75%

Positive Predictive Value 90%

Negative Predictive Value 37%

Diagnostic Imaging

Radiographs 24% (25/101)

Irregular sesamoid bones 1/25

Mineralization in DFTS 1/25

Negative radiographs 92% (23/25)

1) Fibrillated

tendon

2) Granulomata

Surgical Management

Motorized Synovial Resector

+/- Radiofrequency probe

75%

Manual Debridement

Arthroscopic punch forceps

Ferris-Smith Rongeurs

25%

PAL Desmotomy 68%

Palmar Annular Ligament Desmotomy

If,

Chronic case

Ultrasound thickening of PAL

All performed with a custom hook knife

Rationale

Thickened tissue is painful

Analgesic decompression effect

If DDFT debridement alone not effective, prophylactic transection avoids 2nd surgery

Rehabilitation Bandage for 2-3 weeks

Stall rest 3 months

Hand walking after 10 days

After 3 months, light ridden exercise

Full work 8 months after surgery

Population Data

Unilateral affected 98/101

Bilateral affected 3/101

Age range 1 – 18 years

Age mean 9 years

Clinical duration 2 days to 4 years

Warmbloods 81%

Show jumpers* 51%

Dressage 27%

Right Front* 51%

* p < 0.05

Lameness prior to surgery

Lameness Present 78% (73/93)

Sound 22% (20/93)

Distal limb flexion positive 84% (71/85)

Intrathecal anesthesia 100% (12/12)

Prior treatment

No treatment 11% (11/101)

Prior treatment 79% (80/101)

Rest only 45% (36/80)

Rest & intrathecal therapy 55% (44/80)

PAL desmotomy 2% (3/101)

Distribution of tears

Higher distribution of DDFT vs. SDFT

Higher distribution of lateral vs.

medial

Low prevalence of manica flexoria

injury

Characterization of Tears

Character Value

Long (>7cm) 61%

Short (<7cm) 39%

Superficial (<5mm) 58%

Deep (>5mm) 42%

Lateral DDFT Tear 78/101

Granulomata 20% (16/78)

Intrathecal Adhesions 28% (29/104)

Outcome Criteria:

Clinically

9 months or longer

Return to same level or higher level of work

Negative outcome

Same level of work but reduced frequency

Clinical lameness returned

Cosmetic outcome

Marked reduction or resolution of effusion

Surgery Outcome

Return to previous level

work or higher

38%

Return to lower level of

work

27%

Lameness remained 35%

Effusion fully resolved 12%

Effusion reduced 55%

Effusion unchanged 28%

Effusion worse 5%

Significant Correlations

Use of coblation negatively influenced

Cosmetic outcome

Degree of effusion

Length & depth of tear did not influence function or

cosmetic outcome

Marked post-operative effusion & poor clinical

outcome

Considerations,

Ultrasound is minimally invasive BUT tenoscopy is more accurate

Disrupted tendon fibrils cannot be intrinsically removed Debridement of tear, removal of fibrils, and lavage of DFTS beneficial

Most advanced therapy intervention available

Higher number of horses that underwent PAL desmotomy returned to previous or higher work level Only performed in chronic cases

Earlier presentation after initial signs lead to better functional outcome

However, prognosis with therapy still remains guarded 38% return to previous or higher level of work

Similar retrospective design to Arsenburg’s

paperSample Size 76 horses

Age (6 - 10 years) 42% (32/76)

Warmblood 45% (34/76)

Pleasure Riding 48% (37/76)

Duration of Clinical Signs Mean 16 weeks

Rest only 70% (53/76)

Intrathecal injection 16% (12/76)

Radiographs – No

abnormalities

92% (33/36)

Tenoscopy - Pathology

Longitudinal tear of DDFT 60% (45/76)

Torn Manica flexoria 30% (23/76)

Longitudinal SDFT tear 14% (11/76)

Sheath tear 6% (5/76)

Torn digital manica 2% (2/76)

Torn lateral plica of DDFT 2% (2/76)

Intrathecal Adhesions 5% (4/76)

Longitudinal Tears

Longitudinal tear of DDFT 60% (45/76)

Proximal to Sesamoidean

Canal

73% (33/45)

Within Sesamoidean Canal 7% (3/45)

Distal to Sesamoidean Canal 22% (10/45)

Long tears 43% (16/37)

Short tears 56% (21/37)

Lateral tear 71% (20/28)

Torn Manica flexoria

Incidence 30% (23/76)

Hind-limb 74% (17/23)

Only injury 56% (13/23)

Location

At/adjacent to SDFT

100% (23/23)

Complete vs. Partial

Tear

18 vs. 5 (/23)

Medial vs. Lateral 12 vs. 6 (/18)

Adherence to DFTS 35% (8/23)

Reflected to opposite

side

75% (6/8)

Ultrasound vs. Tenoscopy

Ultrasound Tenoscopy Agreement 49% (35/72)

Longitudinal Tears Manica Flexoria Tears

Sensitivity 71

%

Sensitivity 38%

Specificity 71

%

Specificity 92%

Positive Predicative Value 71

%

Positive Predictive Value 67%

Negative Predicative Value 55

%

Negative Predicative

Value

78%

Treatment

Motorized synovial resector for torn fibrils

Arthroscopic scissors, meniscectomy knives,

Ferris-Smith rongeurs for granulomatas

Partial tears of manica flexoria debrided

Complete tears of manica flexoria, MF removed

Rehabilitation

2 weeks strict stall rest

Following suture removal, 6 weeks of stall rest

with controlled hand-walking

Then, 6 weeks of light exercise

Return to normal working regime 3 – 18 months

post-operatively

Mean 7 months

Clinical results

61 horses, >6 months

Sound 68% (41/60)

Same or higher level of work 54% (31/57)

DFTS Effusion Reduced 69% (36/52)

DFTS Effusion Resolved 33% (17/52)

Longitudinal Tear Return to Work 42% (14/33)

Manica Flexoria Tear Return to Work 67% (10/15)

Correlations

Presence of clinical signs >15 weeks

Persistent post-operative DFTS effusion

Marked pre-operative DFTS effusion

Reduced levels of post-operative performance

No improvement in post-operative DFTS effusion

Long tears (vs. short tears)

Reduced levels of post-operative performance

Routinely identified after PAL desmotomy Early cases - horses presented for PAL, concurrent MF identified

Later cases - PAL performed for ease of instrument movement

Intra-operative decision on debridement or MF resection

Sample Size 65 torn MF in 53 horses

Breed - Cobs 53% (28/53)

Breed - Ponies 32% (17/53)

Lameness Duration 3 months (median)

Hindlimbs 83% (54/65)

Median lameness Grade 2 (36/53)

Intrathecal analgesia + 80% (19/24)

Low 4/6 Point + 100% (14/14)

Manica flexoria resection

3rd Portal Lateral, Distal MF

Dissection performed with #12 blade or 14 gauge needle

4th Portal

Lateral, Proximal MF Rongeurs

5.2mm suction punch

Manica flexoria resection continued,

Rehabilitation

3 weeks strict stall rest

Then, 3 weeks small paddock & hand walking

Evaluated at 6 weeks

Sound, return to work

Lame, injected DFTS with 5mg triamcinolone

Repeat assessments every 4-6 weeks until sound

Ultrasound

Ultrasound exams 45/65 limbs

PAL enlargement 53% (24/45)

Thick or torn MF 27% (12/45)

Irregular SDFT / DDFT 9% (4/45)

Radiograph Abnormalities 0/4

Manica flexoria pathology

Acute 30% (20/65)

Chronic (thick or adhered) 70% (45/65)

Medial tear MF 66% (28/42)

Lateral tear MF 26% (11/42)

Axial tear MF 7% (3/42)

Clinical outcome

>3 months follow-up

Mean follow up 20 months

Range follow up 3 – 128 months

Return to same or higher

level

79% (42/53)

Lower level of work 13% (7/53)

Persistently lame 6% (3/53)

Second tenoscopy 7% (4/53)

Adhesions at previous MF resection site 50% (2/4)

New tear in DDFT 50% (2/4)

Conclusions:

Ultrasound is easily accessible and minimally invasive

BUT, is not reliable for diagnosis of intra-thecal DFTS pathology

Tenoscopy remains good standard MRI?

No controlled studies comparing tenoscopy treated population to rest alone

What is true benefit attained from surgery?

Longitudinal tears of DDFT/SDFT

Most often lateral and DDFT

Prognosis is 30-40% with tenoscopy

Manica flexoria tears

Most often medial

Prognosis is >80% with tenoscopy