Wing Injuries

Kimberly A McMunn MS MPH DVM – Anatomy Review – Radiological Positioning – Patient Evaluation – Approaches to Fracture Management – Physical Therapy – Monitoring Healing – Complications – Treatments for Specific Injuries Anatomy of the Wing

Proctor and Lynch 1993 Wing Musculature- Ventral

Proctor and Lynch 1993 Wing Musculature- Dorsal

Proctor and Lynch 1993 Wing Musculature- Flight

Proctor and Lynch 1993 Flight bones

Scott 2016 Wing Vasculature

Proctor and Lynch 1993 Bird bones vs mammal bones

– Bone cortices thin and brittle but very strong, with high calcium content – Any defect in wall greatly reduces their strength – Less holding power (compared to mammals) for fixation hardware – Limited soft tissue over many long bones, very thin skin, bone fragments exteriorize easily Bird bones vs mammal bones

– Pneumatic bones- humerus, and ulna in some species (Pelicans and CA condors) – Majority of callus tissue in healing is derived from the periosteal surface, and blood supply to the periosteum from surrounding soft tissues is very important. The IM circulation appears to be of less significance in avian bone healing than in mammals Radiographic Positioning 2 Orthogonal Views!!

Scott 2016 Evaluation of the Patient

– Evaluate signalment, history, and physical and orthopedic exams – Hands-off observation for mentation, posture, respiration and general appearance – Consider anesthesia or sedation for exam – Consider co-morbidities, including eye, head or intracoelomic trauma in wild birds, or malnutrition and associated poor bone condition in companion birds Differential Dx for Wing Droop/Fractures

– Infectious: Bacterial, Fungal (Aspergillosis) – Metabolic: Gout – Nutritional: Ca deficiency, Ca/P imbalance, Vit D deficiency, excess protein – Toxicosis: Lead, Zinc – Physical: TRAUMA, brachial plexus avulsion – Neoplastic Clinical signs of fractures

– Wing droop – Local swelling – Apparent loss of limb function – Localized pain – Altered limb positioning – Inability to elevate wing above the horizontal plane (key clinical finding in coracoid fractures) Factors contributing to Fractures

– Poor bone integrity, especially in captive birds- malnutrition (inadequate calcium), lack of exercise (loss of bone mass), lack of vitamin D – Reproduction in female birds- calcium deficit – Underlying bone disease- neoplasia, osteomyelitis Basic Orthopedic Principles

– Establish early and complete rigidity – Maintain normal longitudinal and axial alignment, as well as bone length – Promote load-sharing with the bone when possible – Return the limb to normal function and ROM ASAP – Reduce morbidity – Promote patient mobility and comfort Approaches to Fracture Management

– Confinement/Cage Rest – External Coaptation – Surgical Fixation – Instances occur where all three are used simultaneously or successively – Regardless of method, Fx require active management to ensure optimal outcome Prognosis and choosing best approach

– Goal of repair (flight?) – Simple vs comminuted – Site of fracture – Open vs closed, infection – Size of the bird – Comorbidities – Acute vs chronic – Age of the bird Prognosis

– Companion and aviary birds rarely require full mobility, generally excellent prognosis – Wild birds must have near perfect wing function to survive in the wild. Any slight rotation in the distal wing can alter flight. If synostosis occurs, the bird may not be able to fly. – Suggestions that pneumatic bones heal slower than medullary bones – Clinical stability may precede radiographic evidence that the bone is healed Prognosis

– Open fractures- exposed bone readily separates from blood supply, high risk of bone infection, poorer prognosis- if there is ANY skin wound present, assume open – High-energy forces are more likely to shatter a bone, resulting in comminuted fracture, often with significant soft tissue damage, fractured bone cannot contribute to load-sharing, poorer prognosis – Low-energy forces (collision with stationary object) often results in simple transverse or oblique fracture, often easier to repair, with better prognosis – Proximity to a joint- if flight is required, fractures involving elbow or carpus have poor prognosis Amputation

– Federally protected species- cannot amputate above elbow – Companion birds- may be an option – Ability of bird to adapt depends on their size, demeanor and required return to function – Amputation through bone is preferred to disarticulation, the bone end will atrophy and maintain adequate soft tissue coverage – Parrots do learn to adapt to wing amputation at the proximal 1/3 of humerus Approaches to Fracture Management

Ponder and Redig 2016 Cage Rest

– Suitable in a very small number of situations – Very small birds – Injuries not amenable to bandaging or surgery Coaptation

– Requires less skill/experience than surgical fixation – Most common for initial or temporary immobilization – Preferred method for shoulder girdle fractures and metacarpal fractures Coaptation may be considered if

– Full return to function is not required – Fx are pathologic as a result of metabolic bone diseases – Bones are too soft to hold hardware – The patient is too small for internal fixation alternatives – The surgical or anesthetic risk is judged to be too great Coaptation- warnings

– Monitor carefully for tissue abrasions, swelling, slipping – Pad well to prevent pressure necrosis – Higher incidence of synostosis especially in distal third of radius/ulna – Prolonged use can decrease ROM or patagial contracture – Chances of achieving and maintaining functional alignment are generally poor when managed by coaptation alone Coaptation- Body wrap

– With or without Figure-of-8 bandage – Temporary stabilization of wing fractures – Treatment of shoulder girdle problems such as coracoid Fx or luxations – Stabilization of radius OR ulna fracture (increased risk of synostosis and non-union relative to surgical repair) – With metacarpal splint for treatment of distal wing fractures – Careful to allow respiratory movements Coaptation- Body Wrap

Ponder and Redig 2016 Coaptation- Figure-of-8 Wrap

– Stabilize wing Fx distal to elbow, or on reduced elbow luxations – Longer term use (>7-10 days) increases risk of complications- fibrosis and decreased ROM due to hyperflexion of carpus, fibrosis and contracture of patagium – Keep lightweight with minimal bulk – PT at least twice a week, more frequently if any decrease in ROM noted Coaptation- Figure-of-8 Wrap with Body Wrap

Mitchell and Tully 2009 Coaptation- Curved Edge Splint

– Moldable thermoplast or SAM Splint – Support for metacarpal Fx – Placed on ventral surface and curved up along the leading edge of the wing, sandwiched with tape, body wrap – Lateral edge bent up at 90 degrees, does not extend above the plane of the dorsal surface of the wing (does not wrap around the carpus) – Monitor for soft tissue swelling Coaptation- Curved Edge Splint

Ponder and Redig 2016 Coaptation- Robert Jones

– NOT recommended for wing injuries – Difficult to apply, uncomfortable for patient – Too heavy for the wing Coaptation- Tape Splint

– Used in small birds for leg fractures Surgical Fixation

– Usually better functional alignment – Increased capacity for normal use of limb during healing, preventing loss of range of motion due to soft tissue or tendon contracture, as well as improve facture healing Surgical Fixation

– Fixation device should – Be rigid, lightweight, versatile, and removable – Stabilize the forces that apply tension, torsion, shearing, and bending movements to bone – Provide load-sharing with the fracture where possible, load- bearing when not Surgical Fixation Types

– Intramedullary (IM) pin – External skeletal fixator (ESF) – Hybrid fixator ESF-IM – Plates and nails – Cerclage wires – Shuttle Pins Surgical Fixation- IM Pin

– Provides excellent opposition to bending forces of a long bone and good alignment, applied relatively easily – Does NOT provide resistance to torsional, compressive and tensile forces, therefore typically used with coaptation or with ESF – Must secure pin so it does not fall out, or patient does not pull it out – Most common use of single pin is in radial fracture – Single pins should fill ½ to 2/3 of medullary cavity Surgical Fixation- IM Pin

Bennett 1992 Surgical Fixation- ESF

– Resists rotational movement, compressive and tensile forces, moderate bending; difficult to get good end-to-end alignment of the bone fragments – Critical to ensure that each ESF pin engages both bone cortices – Used alone when an IM pin cannot be used due to joint impingement, or in highly comminuted fractures with significant soft tissue compromise – If used alone, requires 2 ESF pins in each fracture segment, one close to the end of the bone and the other as close to the fracture as possible – Often used for metacarpal or ulnar fractures Surgical Fixation- ESF

Bennett and Kuzma 1992 Surgical Fixation- Hybrid Fixator (ESF-IM tie-in)

– Inexpensive, easily learned, lightweight, adaptable, and often very effective – Incredible strength and integrity, resisting all forces on bone, allows for good bone alignment – Consists of an IM pin, 2 ESF pins, and an external connector to join them – Additional ESF pins can be used if load-bearing needs to be handled by the fixator – Sequential dismantling of the fixator allows transfer of load-bearing to the bone, promoting bone healing ESF-IM tie-in

Ponder and Redig 2016 Intra-Op Notes

– Verify pin placement with intra-op radiographs – Check rotational alignment of fracture with comparison to other wing – Check length of bone is correct, especially in comminuted fractures External connectors- FESSA System External Connectors- Other types

– Metal bar – Acrylic bar – Rubber tubing (Penrose drain, IV tubing, PVC tubing, straw) filled with methylmethacrylate (ie hoof repair material) or car body filler – Thermoplastic- sheets or pellets, formed around the pins – Methylmethacrylate putty- same as thermoplastic Surgical Fixation- Plates and Nails/Screws

– Mostly used for leg fractures in larger birds – Limitations include lack of suitably sized plates and nails/screws to accommodate wide range of bone sizes, lack of strength in small plates to accommodate applied forces, morbidity associated with placement including ischemic necrosis of the skin pulled over the plate at closure, and expense – Stress junction at the end of the plate is susceptible to fracture Surgical Fixation- Plates and Nails/Screws

Bennett and Kuzma 1992 Surgical Fixation- Cerclage Wires

– Cerclage, hemicerclage and interfragmentary wires can be used with internal or external coaptation to neutralize rotational and shear forces – Most useful for adding stability to long oblique and spiral fractures and for holding fragments of bone in apposition during the application of other fixation devices Surgical Fixation- Cerclage Wires

Bennett and Kuzma 1992 Surgical Fixation- Shuttle Pins

– Plastic and acrylic rods, lighter than IM pins, biologically inert, provide stable fracture repair and do not require removal – Allow rapid post-fixation exercise (7-10d) and most birds were able to fly 14-21 days post-surgery – Shuttle technique technically difficult, the length of the pin is limited to the longest fracture segment and the pin may not be passed into the shorter fragment segment to a sufficient depth to provide adequate stability Surgical Fixation- Shuttle Pins

Foreign material remains in the medullary canal, which may alter the biomechanical response of a portion of the wing to stresses induced by flight Redig 2000 Surgical approaches

– Identify and follow the natural separations between muscles and along facial planes – Ideally, avoid muscles completely to reduce the surgically induced soft tissue damage – Incision or bruising of the propatagium should always be avoided Post-Surgery

– Body wrap for several days until the bird can support the wing itself – Usually can remove wrap within a week and allow patient to return to normal ROM on its own – Nutritional support including calcium, Vit A and D Physical Therapy- Goals

– Promote mobility and joint ROM – Improve circulation to injured limb – Maintain soft tissue integrity – Reduce the recovery time required after surgery or trauma Physical Therapy- Timeline

– Examine and perform passive ROM, stretching and massage – Start day 3 post-op – Two to three times a week in first 2-3 weeks, then taper

– Elbow extension 140 deg +, wrist extension 180 deg – Goniometer Monitoring Healing

– Recheck rads at 10-14d and 20-24d postop, biweekly thereafter until healed – Staged deconstruction of fixator can begin when early signs of callus formation are seen radiographically – Any pins showing signs of loosening should be removed first – Remove hardware when fracture is stable and good evidence of bone healing – Most can be removed in 4-6 weeks, young birds (<4 weeks old) more rapid- 10-14 days Complications

– Loose pins- exudate, radiolucent halo at the intersection of a fixation pin and bone – Radioulnar synostosis- can be removed, can place fat pad to deter recurrence – Sequestration of bone fragments- especially in comminuted fractures, evidence can be seen after ~3 weeks: radiolucent area around a bone fragment or segment of bone, surgical removal recommended – Osteomyelitis- exudate around pins, signs of inflammation, draining tract- C&S, clindamycin (50 mg/kg q12h PO or 100 mg/kg q24h PO), may require removal of IM pin, AIPMMA bead implantation Complications

– Non-unions- secondary to osteomyelitis, from inadequate fixation, or compromised blood supply: remove scar tissue and freshen bone ends – Poor ROM- prevent with repairing Fx as soon as possible, attempt to get rigid fixation, do PT early and often – Retrograde placement of pins through distal humerus, normograde from lateral or medial epicondyle of the humerus, placement through the distal ulna or retrograde placement from the elbow can cause severe periarticular fibrosis and wing dysfunction Osteomyelitis

Scott 2016 Post-Implant removal

– Flighted birds should start exercising – Wild birds- creance line training or exercise in flight cage – Start at 2-3 cage lengths daily, gradually work up to 14-15 lengths once or twice a day over a 2 week period Return to full flight

– Look for: – ability to glide final 30-40% of length – no labored/open-mouthed breathing – no asymmetry from front, side or behind – take only a few wing beats to get into a smooth flight pattern and level flight should be maintained – no excessive feather noise in hawks – owls should be silent after the first few wing beats Summary

– Best outcomes will be achieved when: – Close attention is paid to soft tissue preservation – When there is early and rigid stabilization of the fracture – When the fixation maximizes opportunity for the patient to maintain range of motion and use of the limb – Cage rest, coaptation and surgical fixation may be used, depending on the characteristics of the individual situation and the desired outcome Specific Injuries of the Wing

Best approaches Patagial injury

– Perforation, tearing – Healing often results in contracture, altering the conformation and restricting extension of the wing – Sutures do not hold well in the patagium- can suture cardboard splint over the area, replacing it every 7-10 days until the defect is healed- support of the cardboard allows extension of the wing during healing Coracoid Fractures

– Very common after blunt force trauma, cause inability to fly and wing droop – 2 types: Midshaft with medial displacement of distal fragments, or luxation of synovial joint where coracoid attaches to sternum – Wing-body wrap if minimally displaced, odds of return to flight very high (>98%) – IM pin if markedly displaced coracoid fracture Coracoid Fracture Protocol in Wild Birds

– Oral meloxicam and tramadol for 10d – Body wrap with PT 2x/wk for 2 weeks – Then small cage without wrap for 2 weeks – Then flight cage 2 weeks – Or: strict cage rest for 3 weeks (no body wrap/PT) Coracoid Fracture- IM Pin Placement

– Skin incision at caudal furcula laterally, continuing medially then along lateral edge of keel for 1/5 length of keelbone – Incise through the superficial pectoral muscle along the caudal edge of the furcula, elevate from keel medially, be aware of clavicular artery at caudal midpoint of the furcula – Penetrate deep pectoral muscle to locate coracoid – Radiosurgery recommended, irrigation necessary to keep the surgical field clean – Rotate proximal fragment of coracoid into incision, clean and debride, IM pins introduced and exteriorized through the point of the shoulder – Distal fragment rotated up into view and cleaned, fracture aligned, IM pins normograded back into distal fragment, with care not to penetrate sternum and perforate pericardium and heart – Muscle bellies reapposed with simple continuous pattern and absorbable suture material, superficial pectoral m can also be secured to the furcula – Wing wrapped to body for 5-10 days post-op Coracoid Fracture- IM Pin

Martin and Ritchie 1994 Clavicle/Scapula Fractures

– Less common than coracoid fractures – Same protocol and good prognosis Shoulder luxations

– Usually accompanied by avulsion fracture of the ventral tubercle of the proximal humerus – Can be stabilized by Figure-of-8 bandage to immobilize the wing to the body for 10-14 days – Sx approach may be needed to reduce and reattach the ventral tubercle with wires or lag screws – Luxations do not necessarily mean poor prognosis for return to complete function, if addressed soon after the injury occurs Humerus Fractures

– Very common, and very commonly displaced due to contraction of pectoralis and biceps brachii muscles – Prognosis poor if torsion occurred at fracture site, causing massive soft tissue swelling distal to the elbow – ESF-IM tie-in if return to normal function required – IM pin normally placed retrograde into proximal bone fragment – Generally dorsal approach, avoid radial nerve Proximal Humeral Fractures

– Minimal displacement- often heal well with Figure-of-8 wrap combined with a body wrap – Displaced fractures, or minimally displaced Fx but wanting to maximize chances of flight, require internal fixation – Tension band technique has been described (Redig 2000)

– Redig PT: Master class: Anatomical and surgical considerations of the avian thoracic limb. Proc Assoc Avian Vet, 2000, pp429-438 Mid-diaphyseal Fractures

– Tend to be oblique fractures, best managed with a ESF-IM tie-in – Radial nerve crosses the dorsal aspect of the humerus at ~1/2 the length, must be identified and preserved

1) retrograde (away from the fracture site) method for open fractures 2) normograde (toward the fracture site) method for closed fractures Martin and Ritchie 1994 Humerus- ESF-IM tie-in

Ponder 2017 Humerus- ESF-IM tie-in

Ponder 2017 Humerus- ESF-IM tie-in

Ponder 2017 Normograde placement of IM pin in humerus

Helmer and Redig 2006 Distal humeral fractures

– Problematic if within 2-3 bone diameters of the distal humeral condyles, as there is insufficient space for an IM pin to gain purchase in the distal fragment – A cross-pinning technique has been described (Redig, 2000) Elbow Luxation

– Present with wing droop, very swollen joint, and poor ROM – Acute luxations can be nonsurgically reduced, joint immobilized with Figure-of-8 bandage for 7-10 days to 2 weeks, safest to skip PT (can re-luxate), then cage rest another 2 weeks without wrap – Flex and extend the elbow while applying pressure to the dorsal aspect of the radius to force it back into articulation with the humerus- if repositioned properly, the joint should regain full ROM Elbow Luxation

– Prognosis for return to function fair to good if treatment prompt (within days of initial injury) – If severe ligament disruption, imbrication or trans-articular fixation have been described (Redig 2000), prognosis for return to normal function poor – In one report 5/9 raptors with elbow luxations were successfully returned to the wild following closed reduction and support with external fixators or bandages for 7-10d Radius and Ulna- single Fx

– External coaptation is an option in small companion birds when displacement minimal- potential complications include patagial contraction due to prolonged immobilization and formation of synostosis between displaced fragments and the other bone – If return to normal function *required*, IM pin or ESF or combination – Prognosis for diaphyseal fractures good – Very proximal radius/ulna fx may be managed only by transarticular ESF with very poor prognosis for return flight Radius and Ulna- both Fx

– IM pins or ESF are optimal for return to flight, and given the greater rigidity obtained and shorter healing time, radius and ulnar fixation recommended – Shuttle pins may also be used in place of IM pins – Avoid radial nerve and artery, in the intraosseous space between the radius and ulna Radial Fractures

– Dorsal or ventral approach for radius – IM pins in radius normally placed retrograde into distal bone fragment or normograde from carpus; penetrates joint and may not allow full ROM, remove pin early Ulnar Fractures

– If bone ends overlap by at least 50%, a Figure-of-8 wrap (and PT) may be effective – Waiting a few days can improve the situation, bone fragments can be pulled back into place – Dorsal approach to ulna – IM pins in ulna normally placed normograde from proximal end- retrograde placement CI as it risks exiting the pin at the olecranon and damaging the joint Ulnar Fractures

Scott 2016 Ulna- IM pin placement

Ponder 2017 Normograde placement of IM pin in ulna

Helmer and Redig 2006 Helmer and Redig 2006 Helmer and Redig 2006 Carpometacarpal Fractures

– If the single artery and vein located between the 3rd and 4th metacarpal bones are damaged, avascular necrosis to the distal portion of the wing can occur – Little soft tissue to protect and provide blood supply, high incidence of open comminuted fractures → lower rate of successful fixation than other avian fractures, longer time to heal – Dorsal approach is most direct Carpometacarpus

– If closed and minimally displaced, Figure-of-8 bandage, curved edge splint – If not, IM pins and/or ESF

Retrograde in proximal fragment

Ponder 2017 References

– Bennett, R. Avery, and Alan B. Kuzma. “Fracture Management in Birds.” Journal of Zoo and Wildlife Medicine, vol. 23, no. 1, 1992, pp. 5–38. JSTOR, JSTOR, www.jstor.org/stable/20460265. – Helmer, P, and Redig, PT. Chapter 34: Surgical Resolution of Orthopedic Disorders. In Harrison GJ and Lightfoot TL Eds. 2006. Clinical Avian Medicine Volume 2. Spix Publishing, Palm Beach. ISBN: 00-9754994-0-8 – Martin, HD, and Ritchie, BW. Chapter 42: Orthopedic Surgery Techniques. In Ritchie BW, Harrison GJ, and Harrison LR, Eds. 1994. Avian Medicine: Principles and Application. Wingers Publishing, Lake Worth, FL. ISBN: 0-9636996-0-1 – Mitchell, M.A. and Tully, T.N. Jr. 2009. Manual of Exotic Pet Practice. Saunders Elsevier. St Louis, Missouri ISBN: 978-1-4160-0119-5 References

– Ponder, JB, and Redig, P. Chapter 21: Surgery, subsection: Orthopedics. In Speer, BL Ed. 2016. Current Therapy in Avian Medicine and Surgery. Elsevier, St Louis. ISBN: 978-1-4557-4671-2 – Ponder, J, and Willette, M. Chapter 3: General Fracture Management of Wild Birds. In Duerr, RS and Purdin, GJ, Eds. 2017. Topics in Wildlife Medicine Vol 4 Orthopedics 2017. National Wildlife Rehabilitators Association, St Cloud. ISBN: 978-1-931439-30-5 – Proctor, N.S. and Lynch, P.J. 1993. Manual of Ornithology Avian Structure & Function. Yale University Press. New Haven and London. ISBN: 978-0-300- 07619-6 References

– Redig, P. Chapter 6: Trauma-Related Medical Conditions, subsection Fractures. In Samor, J Ed. 2000. Avian Medicine. Mosby, London. ISBN: 0-7234-2960X – Redig, P.T. Master Class: Anatomical and surgical considerations of the avian thoracic limb. Proc Assoc Avian Vet, 2000, pp429-438 – Rupley, AE. 1997. Manual of Avian Practice. Saunders, Philadelphia. ISBN: 0- 7216-4083-4 – Scott, DE. Raptor Medicine, Surgery and Rehabilitation, 2nd Edition. CABI, Boston. ISBM: 978-1-78064-746-3 Questions?

– Tippecanoe Animal Hospital 765-447-5088 – [email protected]