Partial Tarsal Arthrodesis Acknowledgments Objectives

Partial Tarsal Arthrodesis

David Dycus, DVM, MS, CCRP, DACVS-SA Nexus Veterinary Bone & Joint Center Nexus Veterinary Specialists Baltimore, MD

Co-Founder/Co-Director Veterinary Sports Medicine and Rehabilitation Institute (VSMRI)

Acknowledgments

Objectives

• Appreciate the anatomy of the tarsus

• Understand diagnostic techniques to diagnose instability

• Discuss surgical techniques for partial tarsal arthrodesis

• Possible reason for susceptibility to over stress injuries

Anatomy • 7 tarsal bones held together by a variety of ligaments

• Fibrous component of joint capsule forms a sleeve from the distal tibia to the proximal metatarsals

• All the tarsal ligaments are contained within this sleeve

• Stronger on the plantar surface • Ligamentous support is complex but critical

Anatomy • High motion

• Tibiotarsal joint • Low motion

• Proximal inter-tarsal joint

• Distal inter-tarsal joint

• Tarsometatarsal joint

Dorsal Aspect of Tarsus

• Numerous intertarsal ligaments maintain stability of the tarsus

Plantar Ligaments

• Damaged in hyperextension injuries

• Typically do not heal with conservative management

Plantar Aspect of the Tarsus

• Tarsocrural instability • IntertarsalAll orMay tarsometatarsal be Treated With Arthrodesis instability if Primary Repair isn’t Feasible • Tarsal fracture • Common calcanean tendon injury

Tarsocrural Luxation • Single or bilateral collateral rupture • Assess for vascular compromise • May result in severe intra-articular damage

Tarsocrural Luxation

“Tiger” 6 yo MN DSH

Tarsocrural Luxation

“Tiger” 6 yo MN DSH

Tarsocrural Luxation

“Tiger” 6 yo MN DSH

• Minimal intra-articular damage • Bilateral collateral reconstruction • Severe articular surface compromise • Consider arthrodesis

Diagnosis of Tarsal Instability

• Exam ﬁndings

• Tarsal swelling

• Tarsal instability

• Pain on tarsal manipulation • Diagnostic imaging

• Orthogonal radiographs

• Include stressed views

• Determine level of injury

Arthrodesis Decision Making

Reconstructable fracture

Collateral injury, articular cartilage intact Primary Repair

Acute Calcanean Tendon Injury

Shearing Injury with Minimal Bone Loss

Non-reconstructable Fracture

Plantar ligament damage

Arthrodesis Chronic calcanean tendon injury with contracture

Intertarsal or tarsometarsal joint aﬀected

Tibiotarsal joint normal Partial Tarsal

Collateral ligaments intact

Tibiotarsal joint aﬀected Pantarsal

Calcanean tuberosity or tendon injury

Diagnosis of Tarsal Instability - Determine the level of Injury!

Stress Views are Key!! Varus/Valgus

Diagnosis of Tarsal Instability - Determine the level of Injury!

Stress Views are Key!! Varus/Valgus

Dorsal/Plantar © 2020 Nexus Veterinary Specialists NEXt level veterinary medicine Intertarsal & Tarsometatarsal Instability • Hyperextension injury • Varus/valgus instability • Concurrent fractures common • Primary surgical repair rarely feasible

• Typically treat with partial tarsal arthrodesis

Diagnosis of Tarsal Instability - Determine the level of Injury!

• Medial plane instability or dorsomedial instability

• Consider tarsal wiring • ENSURE NO PLANTAR INSTABILITY

• If present then will require partial tarsal arthrodesis

Diagnosis of Tarsal Instability - Determine the level of Injury!

• Medial plane instability or dorsomedial instability

• Consider tarsal wiring • ENSURE NO PLANTAR INSTABILITY

• If present then will require partial tarsal arthrodesis

• Fusion of the intertarsal +/- tarsometatarsal joints

• Individual joint fusion diﬃcult to achieve

• Small bones

• Little area for implant purchase • Preserves tibiotarsal joint

Technique for Partial Arthrodesis

• Typically achieved with lateral bone plate

• Plate spans calcaneus to mid- metatarsal region

• Locking plate recommended • IM pin technique & tension band

• Older technique

• Not recommended

Surgical Approach

• Lateral approach to tarsus

• Calcanean tuber to mid- metatarsals

• Incise skin & fascia • Very little soft tissue coverage over lateral tarsus

Pre Op Planning

• Plate size

• Metatarsal bone diameter

• Screw diameter ≤ 40% bone diameter • Plate length

• Calcanean tuber to mid-metatarsals • Plate type

• Locking implants preferred

Pre Op Planning

• Screw length • Screw direction

• Avoid intertarsal joints

• Try to engage 2-3 metatarsals

• Arch in cross section

• Articular cartilage debridement • Bone grafting • Rigid stabilization • Place joint at a functional angle • +/- External Coaptation

Surgical Technique

• Open & debride intertarsal & tarsometatarsal joints

• Remove articular cartilage

• High speed burr

• Sagittal saw • Pack bone graft in debrided joints

• Autogenous Autogenous Bone Graft • Autologous

Pre Op Post Op

Gait Post Partial Tarsal Arthrodesis

Questions

Instagram: ortho_vet David Dycus, DVM, MS, CCRP Diplomate, American College of Veterinary Surgeons- Small Animal Twitter: Ortho_Vet

Chief of Orthopedic Surgery, FB: Dr. David Dycus Nexus Veterinary Bone and Joint Center

Medical Director, Nexus Veterinary Specialists (NVS) [email protected]

Co-Founder and Co-director Veterinary Sports Medicine & Rehabilitation Institute (VSMRI) www.vsmri.com