{"id":30741,"date":"2022-04-12T13:35:49","date_gmt":"2022-04-12T13:35:49","guid":{"rendered":"https:\/\/todaysveterinarypractice.com\/?p=30741"},"modified":"2022-05-25T12:57:38","modified_gmt":"2022-05-25T12:57:38","slug":"treating-angel-wing-deformity","status":"publish","type":"post","link":"https:\/\/navc.sitepreview.app\/todaysveterinarypractice.com\/exotic-medicine\/treating-angel-wing-deformity\/","title":{"rendered":"Treating Angel Wing Deformity: A Sling for the Wing"},"content":{"rendered":"

Carpal valgus deformity in birds is an occasional pediatric musculoskeletal deformity that primarily affects growing birds. This deformity involves pronation of one or both carpi and dorsolateral projection of primary wing feathers. It is also known as angel wing; other synonyms include airplane, slipped, tilt, crooked, rotating, flipped, dropped, reversed, straw or healed-over, sword, or spear wing.\u00a0<\/span><\/span><\/p>\n

Signalment\u00a0<\/span><\/h2>\n

Although primarily found in large fledgling waterfowl (e.g., geese, swans), angel wing deformity has also been found in smaller Anseriformes (e.g., ducks) and birds of other orders. It is more commonly seen in captive birds but has been seen in wild bird species as well. Males are more frequently represented. Not all members<\/span> of<\/span> a clutch<\/span> may be affected.1-3<\/sup><\/span><\/p>\n

Among ducks and geese, tropical and temperate species are particularly affected, and the condition is more common during warmer weather, when young birds use more of their dietary energy for growth than for maintenance of body temperature. Typical waterfowl diets of grass and vegetation have a protein content of 17% to 18%; feeding grower pellets or cereals with higher protein content results in faster growth. Ducks are most at risk for angel wing deformity when they are 8 to 12 weeks of age; white Roman geese are most at risk when 6 to 14\u00a0weeks of age.4<\/sup><\/span><\/p>\n

Angel wing deformity has been found to be the most common musculoskeletal abnormality affecting 4 species of captive-bred bustard chicks younger than 30 days of age. A retrospective review found that the condition developed in 18% of bustards reared at an avian research center, typically at 5 to 19 days of age, most commonly in the white-bellied bustard (Eupodotis senegalensis<\/i>).5<\/sup> Sporadically, this condition is seen in other free-ranging wildlife, including herons, pelicans, cormorants, and boobies.6<\/sup> Among parrots, angel wing deformity in captive budgerigars, macaws, and conures has been infrequently reported.7<\/sup><\/span><\/p>\n

Etiology\u00a0<\/span><\/h2>\n

Causes of angel wing deformity are likely multifactorial and include increased intake of high-energy food, rapid growth, and genetics. Nutritional culprits are high levels of protein and carbohydrates and\/or altered calcium:phosphorus ratio as well as deficiencies in vitamin D3<\/sub>, vitamin E, and manganese. Also suspected are incubation and hatching problems, excessive heat during the early growth period, and restricted exercise. Recently, increased stocking density and toxins (e.g., T-2 mycotoxin) have been shown to increase incidence and severity in white Roman geese.4,8<\/sup><\/span><\/p>\n

Feeding high-protein diets (32% protein) to greater sandhill cranes (Grus Canadensis tabida<\/i>) has been shown to lead to a wing deformity rate of 25% during the period of rapid growth (7 to 28 days after hatching). Feeding a 24% protein diet with low (0.73%) levels of sulfur-containing amino acids slows crane growth sufficiently to reduce limb deformities.9,10<\/sup><\/span><\/p>\n

Development\u00a0<\/span><\/h2>\n

When the blood feathers (new feathers formed during growth or after molting) develop faster than the muscles, the metacarpus starts to rotate outward, creating a carpal valgus. The remiges (flight feathers) are often damaged and protrude at abnormal angles, sometimes as severe as 180\u00b0. The feathers may be stripped of their barbules, leaving only the shafts remaining. Flexion and extension of the wing joints may be normal or abnormal. There may be abnormal laxity of the joints and subluxation of the tendon of the propatagium over the carpus. A severity grade classification has been developed (<\/span>TABLE 1<\/span><\/strong>). If not caught immediately and splinted, angel wing deformity may lead to permanent rotational deformity and inability to fly. For unknown reasons, if only one wing is affected, it is usually the left one.<\/span><\/p>\n

After the feathers are fanning out, it is often too late to correct the deformity and birds will be unable to fly. After the bones have mineralized, the condition is permanent.\u00a0<\/span><\/span><\/p>\n

\"\"<\/a><\/p>\n

Traditional Treatments<\/h2>\n

In addition to diet correction and management changes, treatment has traditionally consisted of splinting or surgical correction. If angel wing deformity is left uncorrected, management options are euthanasia or placement in captivity (trimming primary feathers [the longest feathers on the wing, farthest from the body when the wings are extended] if needed to avoid trauma to the wing).\u00a0<\/span><\/span><\/p>\n

Splinting<\/h3>\n

Treatment options have traditionally consisted of early intervention to stabilize the carpus with coaptation, such as a figure-of-8 splint using Vetrap (3M, <\/span>3m.com<\/span><\/a>) or similar flexible self-adhesive bandage. Bandages must be changed every 3 days to allow for wing growth. For mild cases, simply taping the wing on itself in a normal position for 3 to 5 days may be sufficient.<\/span><\/p>\n

Although angel wing is unusual in raptors, a case report of a 4-week-old captive female Northern goshawk (<\/span>Accipiter gentilis<\/i><\/span>) with bilateral angel wing deformity describes resolution of the deformity 2 weeks after application of figure-of-8 bandages.11<\/sup><\/span> Bandages were changed every 2 to 3 days and physical therapy was performed between bandage changes. The diet was changed from day-old chicks to a restricted amount of a variety of avian- and mammalian-derived food items. Although resolution required 1 more week than is typical, this case was successful due to properly placed and frequently changed bandages along with physical therapy.<\/span>\u00a0<\/span><\/span><\/p>\n

Although traditionally used, figure-of-8 splints can cause the following problems:<\/span><\/p>\n