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Retrospective Evaluation of Tibiotarsal Fractures Treated With Tape Splints in Birds: 86 Cases (2006-2015).

Abstract: Tibiotarsal fractures are a common presentation in small bird species and anecdotally have been reported to carry a good prognosis with proper treatment, such as external coaptation. For this retrospective study, the medical records of 5 institutions were reviewed for tibiotarsal fractures diagnosed in companion birds weighing less than 200 g. A total of 86 cases met the inclusion criteria. Cockatiels (Nymphicus hollandicus) (24/86) and budgerigars (Melopsittacus undulatus) (19/86) were the most frequently represented species. Median body weight of the birds included was 72 g (range, 16-182 g). Mid-diaphyseal (46/86) and closed (73/86) fractures with intact, deep pain sensation in the affected limb (69/76) were most frequent. A tape splint alone (79/ 86) or a tape splint in addition to an intramedullary pin (7/86) were applied in all cases. Median time to fracture stabilization based on palpation was 19 days (range, 7-49 days). In most cases (61/ 86), the initial splint applied was maintained until fracture healing was complete. A successful outcome was documented in 92% (79/86) of birds. Fractures caused by a dog or cat attack, birds presenting without deep pain sensation in the affected limb, and cases where the splint was removed before 14 days after fixation were associated with a significantly increased risk of complications, resulting in an unsuccessful outcome. The findings of this study indicated that a tape splint is an appropriate means for treatment of tibiotarsal fractures in birds weighing less than 200 g.

Key words: tibiotarsal fracture, external coaptation, tape splint, trauma, outcome, avian, bird

Introduction

Tibiotarsal fractures are among the most common fractures seen in pet birds and often are associated with mishandling by human caretakers, cage-related trauma, and injuries caused by another pet in the household. (1-3) Consistent with such a common injury, numerous techniques of tibiotarsal fracture repair have been described and recommended. In larger avian species, a variety of surgical stabilization techniques, such as external fixators with or without intramedullary pin placement, have been reported. (1,4-7) However, patient size may be a limiting factor in the feasibility of surgical stabilization of tibiotarsal fractures. (3,7) Therefore, external coaptation currently is the recommended treatment for tibiotarsal fractures in birds with body weights less than 300 g. (5,7) While it has been suggested that external coaptation or splinting is appropriate only in cases where return to adequate function of the limb is not required, numerous other reports indicate otherwise, offering an excellent prognosis for return to normal function. (1,5) The advantages of external coaptation are low cost and ease of implementation, reduced or absent anesthetic risks if splint application is performed under sedation, decreased damage to the vascular supply of the leg, and reduced risk of infection. (8) For external coaptation of tibiotarsal fractures in small birds, tape splints are commonly recommended and widely used. (3,5-7)

To our knowledge, no systematic evaluation of the outcome of tibiotarsal fractures in birds treated with external coaptation has been reported. We retrospectively examined the outcome of tibiotarsal fractures in birds weighing less than 200 g, for which fracture treatment was performed using tape splints.

Methods and Materials

Study protocol

The medical records of 5 veterinary hospitals between 2006 and 2015 were reviewed for this study. Inclusion criteria were adult or subadult birds weighing <200 g, diagnosed with tibiotarsal fractures, and a documented outcome. Patients were excluded from the study if they were juveniles that had not fledged by the time of the fracture diagnosis, had repair without a tape splint for external coaptation, or were lost to follow-up.

Clinicians from each contributing institution reviewed records and submitted information according to a standardized questionnaire. Data collected included age, body weight, and signalment of the birds, cause of the fracture, whether the fracture was open or closed, location of the fracture (proximal, mid-diaphyseal, or distal tibiotarsal), presence or lack of deep pain in the affected limb during the initial physical exam, type of repair used in fracture fixation, use of anesthesia or sedation, use of analgesics or anti-inflammatory drugs, number of bandage changes, time to fracture stability based on palpation, presence of radiographic evidence of bony healing and alignment at time of palpable stability, complications of fracture repair, and final outcome of each case.

A successful outcome was defined as complete fracture healing and the ability to bear weight and ambulate using the affected limb. This outcome was determined subjectively by the attending veterinarian. The goal of this outcome was to allow the treated birds to return to an acceptable quality of life as companion or captive animals.

Statistical analysis

The outcome of interest was whether each fracture healed to a degree to allow an adequate return to function of the affected limb and how long this took to achieve. Summaries of descriptive statistics were presented as mean [+ or -] standard deviation (SD) or median/range. The associations of different factors of each case (disposition of the fracture, duration of splinting, bandage changes, and so forth) with successful healing of tibiotarsal fractures were investigated. To identify factors strongly associated with tibiotarsal fractures and to estimate the odds ratio (OR) as to whether each factor that was examined significantly influenced the outcome of fracture healing, univariate logistic regression analysis was performed using the predictor variables. Multivariable logistic regression analysis was subsequently performed on predictors that were statistically significant in the univariate analysis (except time to first splint removal, which was excluded from the multivariable analysis because the model was poorly fitted with this variable due to missing values). P < .05 was considered statistically significant. All data were analyzed using R statistical software (R Foundation for Statistical Computing, version 3.2.5).

Results

In total, 86 birds kept as companion animals, representing 14 different species, met the inclusion criteria. Psittaciformes were the most common order (74/86, 86%), followed by Passeriformes (9/ 86, 10%) and Columbiformes (3/86, 3%). The most common species were cockatiels (Nymphicus hollandicus; 24/86, 28%), budgerigars (Melopsitiacus undulatus; 19/86, 22%), conures (Pyrrhura species; 9/86, 10%), Quaker parrots (Myiopsitta monachus; 9/86, 10%), and lovebirds (Agapornis species; 8/86, 9%). Male sex was reported more frequently (33/ 86, 38%), while 25/86 (29%) were female, and the sex was unknown or not reported in 28/86 (33%) birds. Ages ranged from 3 weeks to 24 years (median, 2 years). Body weight ranged from 16 to 182 g (median, 72 g).

Common causes for tibiotarsal fractures reported were owner mishandling (19/86, 22%), falling off a perch (8/86, 9%), and trauma caused by a dog or cat attack (6/86, 7%; Table 1). The cause of the tibiotarsal fracture was not reported in 40/86 (47%) birds. Birds with a tibiotarsal fracture caused by a dog or cat attack had a significantly increased risk for an unsuccessful outcome (Table 2).

Fracture location was recorded in 76/86 (88%) cases. Most tibiotarsal fractures were mid-diaphyseal (46/86, 53%), while 19/86 (22%) were within the proximal and 11/86 (13%) within the distal thirds of the tibiotarsal diaphysis. Fracture location was not significantly associated with outcome (Table 1). Most fractures were closed on presentation (73/86, 85%) and an open fracture did not increase the risk for an unsuccessful outcome (Table 2).

Deep pain in the digits of the affected limb was present in 69/86 (80%) cases, absent in 7/86 (8%), and not reported in 10/86 (12%). Most cases that presented initially lacking deep pain in the digits of the affected limb did regain it over time. The absence of deep pain on initial examination was associated with a significantly increased risk of an unsuccessful outcome. However, while the risk of an unsuccessful outcome was increased, 5/7 birds with no deep pain on presentation had a successful outcome.

Most tape splints were applied under sedation (51/86, 59%) without use of general anesthesia. A tape splint was applied alone (79/86, 92%) or in addition to an intramedullary pin (7/86, 8%). Patients were kept in hospital following splint placement from 0 to 5 days (median, 1 day).

Tape splints were removed for a variety of reasons, including to relieve swelling of the digits of the affected limb, evaluate the presence or status of wounds beneath the bandage, check for fracture stability, and perform wound maintenance for open fractures. Median time to initial removal of the tape splint was 14 days after initial splint placement (range, 1-44 days). Splint removal performed before 14 days initial placement was associated with an increased risk of an unsuccessful outcome, compared to those cases where the original splint remained in place for >14 days. In most patients (61/86, 71%), a second splint was not placed after removal of the initial one, since the fracture was considered sufficiently stable as not to require further splinting.

Median time to fracture stability assessed by palpation was 19 days (range, 7-49 days) after initial splint placement. At the time that fracture stability was identified by palpation, 18 cases underwent radiography to evaluate fracture healing. Only 6/18 (33%) cases had radiographic evidence of mineralized callus present at the fracture site.

Overall, the outcome was considered successful in 79/86 (92%) birds, 13 (16%) had mild lameness immediately after splint removal.

Of the 7/86 (8%) birds classified with an unsuccessful outcome, 5 died or were euthanized, and the limb was amputated in 2 because of tissue necrosis of the fractured limb. One of the 7 birds died while under anesthesia for surgical limb amputation. Another bird was euthanized because of progressive necrosis of the fractured limb and the owner's unwillingness to proceed with amputation. The reason for euthanasia was not reported in the remaining 3 birds.

Discussion

Few studies have systematically evaluated the outcome of fracture management in birds. In raptors, the use of external fixators with an intramedullary pin tie-in for repair of tibiotarsal fractures has been evaluated in a retrospective study. (6) Of the 37 birds described in the study, 84% were considered to have had successful outcomes. (6) In another study, a successful outcome was reported in 89% of 28 birds treated with external fixators alone for the management of various long bone fractures, not limited to the tibiotarsus. (4) To our knowledge, no studies have examined the outcome of tibiotarsal fractures after treatment with external coaptation in birds weighing <200 g. Our results indicated that 92% of tibiotarsal fractures treated with tape splints ultimately achieved adequate healing and an acceptable return to function.

Fracture immobilization aims to achieve anatomic alignment with rigid stabilization, while minimizing disturbance of the surrounding soft tissue and any callus formation at the fracture site. (9) Stabilization of a fracture implies neutralization of the forces of shear, compression, rotation, and bending, which is what allows appropriate progression of fracture healing. (7,9) Previous reports conflict as to whether external coaptation accomplishes this goal. Some sources have anecdotally reported that external coaptation fails to achieve adequate stabilization for fracture healing, (1) while others recommend use of external coaptation, primarily in birds weighing less than 200 to 300 g. (3,7) Compared to surgical fracture treatment, external coaptation is a simple technique that can be performed by most veterinarians without the need for specific training. Additional benefits of external coaptation are reduced or avoided anesthesia time and associated complications, as splints can be applied under sedation alone in many cases. Birds presenting with traumatic wounds often are in shock or otherwise systemically compromised, which can increase anesthetic risk. Anesthesia, when used to place a tape splint, is likely to be much shorter than what would be necessary to place any surgical apparatus, reducing the risk of any associated complications. General anesthesia was used in only 41% (35/86) of our cases.

The major reported drawbacks of external coaptation are poor apposition of fracture ends and excess motion at the fracture site. (5,7) However, our results demonstrated a high number of successful outcomes in birds weighing less than 200 g managed with external coaptation instead of surgical stabilization. It also has been suggested that proximal tibiotarsal fractures cannot be sufficiently stabilized by tape splints in small birds. (7) However, our results do not support this statement. Tibiotarsal fracture location was not significantly associated with outcome in the birds included in this study and it appears that a properly placed tape splint is a suitable treatment method for proximal tibiotarsal fractures in small birds.

This study identified 3 factors that were significantly associated with an increased risk for an unsuccessful outcome. Lack of deep pain at initial examination increased the chance of fracture repair failure. Despite this, however, 5/7 birds that initially presented without deep pain recovered sensation in the affected limb and had successful outcomes.

Dog or cat attacks leading to tibiotarsal fractures also were associated with an increased risk of complications. Bites from dogs and cats have been described as being associated with a greater risk of infection than injuries from other sources. (10) More severe soft tissue trauma is possibly the reason for the poorer prognosis of these injuries, although this information was not available in the records reviewed. No fracture associated with dog and cat attacks was classified as open, and no obvious puncture wounds were reported.

Splint removal before 14 days after its initial placement was associated with an increased risk of an unsuccessful outcome. Earlier removal may have led to a greater risk of failure for several reasons. While one possibility is that this earlier removal may have caused an iatrogenic disruption of the healing fracture site, earlier splint removal possibly was necessitated because of evidence that the fracture was healing poorly (eg, presence of ulceration or necrosis of the distal limb below the tape splint).

Complications were found in 16% of cases that healed successfully. The most common complication noted was mild lameness. The acceptability of these complications depends upon the life style of the animal. For our cases, birds were privately owned pets and a mild alteration in gait was not considered a significant negative impact on their quality of life. In the cases for which follow-up documentation was available, the lameness noted after splint removal did not cause any long-term consequences.

Limitations of this study included the inherent restraints of a retrospective design, a relatively small sample size with a skewed sample signalment, incomplete patient records, and the fact that many of the results depended on subjective evaluations by numerous clinicians. Despite these limitations, our results indicated that tape splints are a useful and appropriate treatment method for tibiotarsal fractures in birds weighing less than 200 g. A successful repair rate of 92% compares with those of retrospective studies examining surgical repair of fractures in larger avian species. (4,6) Additionally, knowledge that most birds attained clinically stable fractures capable of bearing their weight may help guide clinicians in determining the most appropriate time to remove these splints.

Louden Wright, DVM, Christoph Mans, Dr med vet, Dipl ACZM, Dipl ECZM (ZHM), Geoff Olsen, DVM, Dipl ABVP (Avian), Grayson Doss, DVM, Dipl ACZM, Ermias W. Amene, DVM, MSc, PhD, Gerd Britsch, Dr med vet, Jane Christman, DVM, and Jill Heatley, DVM, Dipl ACZM, Dipl ABVP (Avian)

From the University of Wisconsin-Madison, School of Veterinary Medicine. Madison, WI 53711 USA (Wright, Mans, Doss, Amene): The Medical Center for Birds, Oakley, CA 94561 USA (Olsen): Vogel und Reptilienpraxis, 76139 Karlsruhe, Germany (Britsch); and Texas A&M College of Veterinary Medicine and Biomedical Sciences. College Station. TX 77845 USA (Christman. Heatley).

References

(1.) Harcourt-Brown NH. Orthopedic conditions that affect the avian pelvic limb. Vet Clin North Am Exot Anim Pract. 2002;5(1):49-81.

(2.) Rosskopf WJ. Common conditions and syndromes of canaries, finches, lories and lorikeets, lovebirds, and macaws. Semin Avian Exot Pet Med. 2003; 12(3):131-143.

(3.) Eshar D, Briscoe JA. External coaptation using a tape splint for treatment of distal pelvic limb fractures in small birds. Lab Anim. 2009;38(8):262-263.

(4.) Hatt JM, Christen C, Sandmeier P. Clinical application of an external fixator in the repair of bone fractures in 28 birds. Vet Ree. 2007; 160(6): 188-194.

(5.) Helmer P, Redig PT. Surgical resolution of orthopedic disorders. In: Harrison GJ, Lightfoot TL, eds. Clinical Avian Medicine: Volume II. Palm Beach, FL: Spix Publishing; 2006:761-774.

(6.) Bueno I, Redig PT. Rendahl AK. External skeletal fixator intramedullary pin tie-in for the repair of tibiotarsal fractures in raptors: 37 cases (1995-2011). J Am Vet Med Assoc. 2015;247(10); 1154--1160.

(7.) Rubin JA, Runge JJ, Mison M, et al. Surgery. In: Speer BL, ed. Current Therapy in Avian Medicine and Surgery. St Louis, MO: Elsevier/Elsevier; 2016: 631-668.

(8.) Doneley B. Avian Medicine and Surgery in Practice: Companion and Aviary Birds. London, UK: Manson Publishing; 2010.

(9.) Bennett RA, Kuzma AB. Fracture management in birds. J Zoo Wildl Med. 1992;23(1):5-38.

(10.) Fleisher GR. The management of bite wounds. N Engl J Med. 1999;340(2): 138-140.
Table 1. Fracture disposition and treatment of
86 birds diagnosed with tibiotarsal fractures.

  Variable                              Number of   Number of cases
                                          cases     with successful
                                                        outcome

Source of trauma
  Owner handling error                     19             18
  Fall from perch                           8              8
  Stuck in cage                             7              6
  Dog or cat bite                           6              3
  Cage mate trauma                          3              3
  Flying accident                           3              3
  Not reported                             40             38
Fracture type
  Closed                                   73             68
  Open                                     13             11
Deep pain on presentation
  Yes                                      69             66
  No                                        7              5
  Not reported                             10              8
Fracture location
  Midshaft                                 46             40
  Distal                                   19             19
  Proximal                                 11             10
  Not reported                             10             10
Repair type
  Tape splint only                         79             74
  Tape splint with IM pin                   7              5
Number of splint changes
  None                                     61             56
  1                                        15             14
  2-4                                      10              9
Time to first bandage removal
  0-7 days                                 22             19
  8-14 days                                27             25
  15-21 days                               28             27
  [greater than or equal to] 21 days        8              8
  Not reported                              1              0

Table 2. Selected univariate and multivariable logistic
regression analysis of predictors associated with unsuccessful
outcome of tibiotarsal fractures in birds following treatment
with tape splints.

                                          Univariate analysis

  Predictor variable                    OR     95% CI     P value
                                                         ([dagger])

Body weight:
  < 40 (a) g
  40-93 g                               2.3   0.31-47       .46
  > 93 g                                3.7   0.42-78       .27
Sex:
  Male (a)
  Female                                3.0   0.54-23       .22
Dog/cat related trauma:
  No (a)
  Yes                                   15    2.3-103       .003
Fracture location:
  Distal and proximal diaphysis (a)
  Mid-diaphysis                         2.1   0.44-15       .38
Fracture type:
  Closed (a)
  Open                                  2.0   0.27-10       .42
Deep pain on initial presentation:
  Present (a)
  Absent                                34    4.2-357       .001
Repair type:
  Tape splint only (a)
  IM pin + tape splint                  4.9   0.61-28       .09
Number of splints applied:
  1 (a)
  1 > 1 (2-4)                           1.2   0.16-6.6      .84
Time to first splint removal:
  > 14 days (a)
  [less than or equal to] 14 days       10    1.6-196       .03

                                         Multivariate analysis

  Predictor variable                    OR     95% CI     P value

Body weight:
  < 40 (a) g
  40-93 g                               --       --         --
  > 93 g                                --       --         --
Sex:
  Male (a)
  Female                                --       --         --
Dog/cat related trauma:
  No (a)
  Yes                                   45   3.8 - 1142    .004
Fracture location:
  Distal and proximal diaphysis (a)
  Mid-diaphysis                         --       --         --
Fracture type:
  Closed (a)
  Open                                  --       --         --
Deep pain on initial presentation:
  Present (a)
  Absent                                68   5.3 - 1900    .004
Repair type:
  Tape splint only (a)
  IM pin + tape splint                  --       --         --
Number of splints applied:
  1 (a)
  1 > 1 (2-4)                           --       --         --
Time to first splint removal:
  > 14 days (a)
  [less than or equal to] 14 days       --       --         --

Abbreviations: OR indicates odds ratio; CI, confidence interval.

(a) Reference category.
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Title Annotation:Retrospective Study
Author:Wright, Louden; Mans, Christoph; Olsen, Geoff; Doss, Grayson; Amene, Ermias W.; Britsch, Gerd; Chris
Publication:Journal of Avian Medicine and Surgery
Date:Sep 1, 2018
Words:3246
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