Keywords
humeral condylar fractures - malunion - intraoperative distraction - dog
Introduction
Fractures of the distal humeral condyle, including lateral, medial or Y/T fractures,
account for approximately 50% of all humeral fractures in dogs.[1] Fractures of the lateral humeral condyle account for approximately 66% of these
cases as the lateral humeral condyle is both directly in line with the thoracic limb's
axis of weight bearing and has a smaller and weaker epicondylar crest than the medial
humeral condyle.[1]
[2] The most common presentations of lateral humeral condylar fractures are Salter Harris
type IV fractures in puppies less than 4 months old and intercondylar fractures in
juvenile and adult dogs.[3] Being intra-articular, acute open reduction and internal fixation of lateral humeral
condyle fractures are always recommended to achieve anatomic reduction, rigid stability
and acceptable limb function.[4]
[5]
Nascent malunion fractures, defined as incompletely healed fractures with poor radiographic
alignment of the lateral humeral condyle are more difficult to treat with surgical
reduction than acute fractures because of the extensive callus formation, scar tissue
and contracture of surrounding tissues.[6]
[7] The surgical approach to these cases has traditionally involved the use of osteotomes
and debridement of callus to facilitate fracture site visualization to aid reduction.
Historically, when these methods were not effective, the fracture was deemed non-reducible
and dogs were managed medically or treated with salvage procedures such as amputation
or arthrodesis.[8]
The objective of this retrospective case series is to describe the use of an intraoperative
distraction device to aid in the reduction and anatomical alignment of nascent malunion
lateral humeral condylar fractures along with long-term functional outcomes.
Case Histories
Medical records for five dogs with seven total lateral Salter-Harris IV fractures
of the distal humerus with proximal displacement and mineralized callus formation
(nascent malunion) treated with intraoperative distraction and internal fixation between
2015 and 2018 were reviewed. All records were obtained from a single referral surgical
practice. Two of the dogs[2]
[4] were presented by rescue organizations. Median estimated age at surgery was 142
days (range: 95–156) and median weight was 13.0 kg (range: 6.7–21.8). Lameness grading
and radiographic osteoarthritis grading were documented in the medical records.[9]
[10] The specifics regarding each dog's history are as follows:
Dog 1 (elbows 1–2) was a 5-month-old, 10 kg intact male bulldog adopted with a known
history of a one-story fall prior to adoption. Intake examination notes ambulation
with a stilted, short-strided forelimb gait. Radiographs revealed nearly symmetric
nascent malunion bilateral distal humeral condylar Salter-Harris type IV fractures
with severe proximolateral displacement and evidence of early remodelling and an osteoarthritis
score of 0.
Dog 2 (elbow 3) was a 4-month-old, 11 kg neutered male Pitbull terrier presented for
evaluation of a ‘fractured elbow’ of unknown aetiology. The dog had a pronounced left
forelimb lameness and severe left elbow thickening. Radiographs revealed a nascent
malunion Salter-Harris IV fracture of the distal left humerus with moderate proximolateral
displacement and mineralized callus formation and an osteoarthritis score of 0.
Dog 3 (elbow 4) was a 3-month-old, 6.5 kg intact female mixed breed dog was presented
with trauma of unknown origin. Physical examination revealed a 3/4 right forelimb
lameness, marked soft tissue swelling around the elbow and limited right elbow flexion.
Radiographs revealed a nascent malunion Salter-Harris IV fracture of the distal right
humerus with significant craniolateral displacement and moderate soft tissue swelling
and an osteoarthritis score of 0.
Dog 4 (elbows 5–6) was a 4-month-old, 22 kg neutered male mixed breed dog presented
for bilateral forelimb lameness. Radiographs revealed nearly symmetric nascent malunion
bilateral distal humeral condylar Salter-Harris type IV fractures with extension through
the lateral aspects of the condyles, severe proximolateral displacement, moderate
mineralized callus formation, regional soft tissue swelling, subchondral sclerosis
of the semilunar notches of the ulnas and an osteoarthritis score of 1.
Dog 5 (elbow 7) was a 4-month-old, 10 kg intact female mixed breed dog presented for
evaluation of a left forelimb fracture of unknown aetiology. Physical examination
found a 4/4 left forelimb lameness with firm elbow thickening and crepitus. Radiographs
revealed a nascent malunion Salter-Harris IV fracture of the distal left humerus with
craniolateral displacement, mild mineralized callus formation, mild soft tissue swelling
of the elbow and an osteoarthritis score of 0.
Preanesthetic biochemistry and haematology results were unremarkable for all dogs.
Surgery
In all cases, a lateral approach to the humeral condyle was performed. Mineralized
callus was debrided with rongeurs and Cottle osteotomes until the fractured condylar
fragment could be identified and mobilized. An Orthofix straight minirail system (Orthofix
LTD, Maidenhead, UK) was then positioned across the fracture site using one 2.4 mm
SCAT pin (IMEX Veterinary Inc., Longview, Texas, United States) placed in the distal
humerus proximal to the fracture and a second 2.4 mm SCAT pin placed in the proximal
radius ([Fig. 1]). The fracture and associated soft tissues were then distracted to reduce the effects
of soft tissue contraction until anatomic reduction of the humeral condylar articular
surface could be achieved. Distraction was maintained for at least 5 minutes.
Fig. 1 (A) A model depicting the lateral surgical approach to the humeral condyle. Red modelling
clay has been used to illustrate callus associated with nascent malunion fractures.
(B) An Orthofix straight minirail system positioned across the fracture site using one
SCAT pin placed in the distal humerus proximal to the fracture and another pin in
the proximal radius. (C) A craniocaudal view of the positioned distraction device. (D) An intraoperative image of the positioned distraction device.
Fractures were stabilized with a cortical transcondylar lag screw with washer in all
cases, as well as a lateral Kirschner wire proximally across the lateral epicondyle
(elbows 1–4 and 7) or a lateral locking bone plate in elbows 5 to 6 (Synthes, West
Chester, Pennsylvania, United States). Transcondylar lag screws were placed using
a retrograde drilling technique. Surgical sites were irrigated with saline and closed
routinely in three layers. Orthogonal postoperative radiographs were obtained in all
cases ([Fig. 2]).
Fig. 2 (A) Preoperative lateral and craniocaudal radiographic images of a nascent malunion
lateral humeral condylar fracture with proximal displacement and mineralized callus.
(B) Immediate postoperative lateral and craniocaudal radiographic images of a nascent
malunion lateral humeral condylar fracture with surgical reduction and fixation. (C) Long-term (14-month) postoperative lateral and craniocaudal radiographic images
of a nascent malunion lateral humeral condylar fracture with surgical reduction and
fixation.
Postoperative Care and Outcomes
All dogs received fentanyl constant rate infusions (3.3 μg/kg/h) and isotonic fluids
overnight and were discharged the following day with oral medications. Analgesics
administered during the initial postoperative period included tramadol (1–4 mg/kg,
per os [PO], q 8 hour) and carprofen (2.2 mg/kg, PO, q 12 hour). All dogs were prescribed
cefpodoxime (7 mg/kg, PO, q 24 hour × 7 days), provided an e-collar, splinted and
bandaged for 10 to 14 days following surgery with instructions for 4 to 6 weeks of
strict rest.
In all dogs, both short-term (< 6 months) and long-term (> 1 year) follow-up evaluations
were recommended, but long-term evaluations were not completed for three elbows. Evaluations
included a physical examination, orthogonal radiographs of the operated elbow(s) and
evaluation of the surgical site for signs of infection as defined by the Centers for
Disease Control and Prevention.[11] Additionally, all long-term follow-up examinations included elbow goniometry as
described by Formenton and colleagues and forelimb circumference measurements.[12] Outcomes were considered successful when dogs returned to adequate function (lameness
grade of 0–1/4) and had no complications requiring a salvage procedure for resolution.[13] Subjective client communication medical record notes about owner-perceived outcomes
were also reviewed.
Dog 1 (elbows 1–2) was non-ambulatory (lameness score 4/4, bilaterally) at the short-term
evaluation (56 postoperative days) due to a surgical site infection. Purulent material
was aspirated from the joint space and submitted for aerobic culture, and the dog
was treated with appropriate antibiotic medications for 2 weeks. Following treatment,
his lameness grade was unchanged and his elbow joints had persistent swelling and
crepitus. Radiographs revealed loss of reduction, craniolateral displacement of the
left elbow and changes consistent with osteomyelitis of both elbows including lucency
along the margins of the transcondylar screws. Salvage procedures were discussed,
but the owner pursued bilateral implant removal surgery the following week. This dog
was lost to follow-up and euthanatized at another hospital 12 weeks following the
procedure. As a result of the catastrophic complications in this dog, treatment was
considered unsuccessful.
Dog 2's (elbow 3) incision site was healing appropriately at the short-term re-check
appointment (27 postoperative days) and radiographs confirmed anatomical alignment
and development of grade 1 osteoarthritis. At the long-term re-check (961 postoperative
days), a 1/4 right forelimb lameness score was noted. No soft tissue swelling or pain
was elicited on palpation or manipulation of the elbows bilaterally. The owner reported
he was very active and comfortable at home but would occasionally hold his right forelimb
up after activity.
Dog 3 did not complete the short-term re-check. A lameness score of 1/4 was observed
at the long-term re-check (749 postoperative days) and the owner communicated that
the dog was active and painless at home. Radiographs obtained at both re-check examinations
demonstrated mild peri-articular proliferation and development of grade 2 osteoarthritis
but appropriate anatomic alignment and fracture healing.
Dog 4's (elbows 5–6) incision sites were healing appropriately at the short-term re-check
(27 postoperative days). The dog had normal range of motion in both elbows with no
observable forelimb lameness. Radiographs confirmed appropriate anatomic alignment
and fracture healing with grade 2 osteoarthritis documented in both elbows. At the
long-term evaluation (411 postoperative days), the dog was walking well but radiographs
revealed a hypertrophic callus formation on the lateral aspect of the right elbow
at the distal end of the plate. Implant irritation was suspected, and implant removal
was performed. At the time of suture removal, the dog's lameness grade was 1/4.
Dog 5's (elbow 7) incision site was swollen at the short-term evaluation (83 postoperative
days), and the dog had persistent 1/4 lameness at trot. Radiographs revealed mild
soft tissue swelling attributed to implant irritation and development of grade 1 osteoarthritis.
The implants were removed. This dog was lost for long-term follow-up.
In the four elbows with long-term follow-up, elbow goniometry, limb circumference
measurements and orthopaedic examination were performed. The measurements were clinically
but not statistically compared between the operated and non-operated limbs in unilaterally
affected dogs. Median angle of elbow extension in the operated and non-operated limbs
was 150 degrees (range: 145–160) and 140 degrees (no range) respectively. Median elbow
flexion angle in the operated and non-operated limbs was 77.5 degrees (range: 50–110)
and 40 degrees (range: 35–45) respectively. Median long-term circumference of the
operated and non-operated limbs was 21.5 cm (range: 21–23) and 26.0 cm (range: 24–28)
respectively.
Discussion
This case series represents the first published group of dogs with nascent malunion
lateral humeral condylar fractures to be treated with traditional open reduction and
internal fixation with the aid of an intraoperative distraction device. Fracture reduction
and anatomic alignment were achieved in all seven elbows. While this independently
demonstrates that the intraoperative distraction device was useful in enabling fracture
reduction in cases of nascent malunion condylar fractures with associated contracture,
we also assessed limb function and monitored postoperative outcomes.
All but one elbow demonstrated proper anatomic alignment and fracture healing at the
short-term evaluations. Additionally, the three dogs (4 elbows) that were presented
for long-term examinations had appropriately healed incision sites, lameness scores
of 1/4 and good owner-perceived mobility and comfort. Of these cases, dog 3 is the
only dog with a recorded pre-surgical lameness score to compare with the long-term
evaluation. Her score improved dramatically from 3/4 to 1/4. Although lost to long-term
follow-up after plate removal surgery, dog 5 also demonstrated dramatic improvement
of limb function, improving from 4/4 to 1/4 at the short-term evaluation. The remaining
dog (2 elbows) was euthanatized for unknown reasons during convalescence, though it
is expected that the owner's decision was influenced by multiple postoperative complications
in that dog's surgical sites, including surgical site infection in both elbows and
loss of reduction in one elbow, which were not seen in the other operated elbows.
Range of motion and circumference measurements of surgical limbs were worse when compared
with the unaffected limb in unilateral cases. Reference measurements for goniometry
and limb circumference data are not available for acutely repaired humeral condylar
fractures, but we suspect they do not consistently return to pre-injury values. When
compared with the reference ranges established by Formenton and colleagues, all measurements
in our cases fell within two standard deviations of the normal dog elbow reference
values.[12]
Progression of osteoarthritis was appreciated radiographically in all dogs except
for dog 1 due to osteomyelitic changes present in the follow-up radiographs. This
progression of osteoarthritis despite proper fracture alignment is consistent with
previously reported results which demonstrated that humeral condylar fracture reduction
score was not correlated to the long-term outcome measured by radiographic osteoarthritis
score.[14] While computed tomography would have been helpful for assessing articulation and
osteoarthritis, Shubert and colleagues reported that assessment of elbow joint osteoarthritis
was consistent between radiographic and computed tomographic examination.[15]
Our report was limited by incomplete and inconsistent follow-up. Intervals from surgery
to recheck evaluations were variable, possibly skewing the results of our limb circumference
and lameness measurements in particular. Additionally, several objective measurements
of functional outcomes including preoperative orthopaedic examinations and specifics
regarding postoperative limb function were not fully documented in the medical records.
In our study, only an Orthofix straight minirail system was utilized for intraoperative
distraction, but we expect that any distraction device would be effective. Lastly,
reduction using solely traditional methods prior to using the distraction device was
not attempted in any cases, making it difficult to form strong conclusions regarding
the use of this device in cases specifically refractory to traditional methods of
reduction alone.
While prospective research into this method is warranted, our case outcomes suggest
that the use of an intraoperative distraction device to aid in anatomical reduction
and fixation of nascent malunion lateral humeral condylar fractures with associated
soft tissue contracture should be considered.
