Heidi Radke

Comparison of Kinematic Variables in Defining Lameness Caused by Naturally Occurring Rupture of the Cranial Cruciate Ligament in Dogs

OBJECTIVE To (1) discover kinematic variables that differ between dogs with cranial cruciate ligament rupture (CCLR) and control dogs and (2) to identify suitable outcome variables for longitudinal studies on the effects of surgical interventions for CCLR in dogs. STUDY DESIGN In vivo case-control comparison. ANIMALS Dogs with unilateral CCLR (n=16), and no other detectable neurologic or orthopedic disease and 10 dogs without CCLR, neurologic, or orthopedic disease. METHODS Kinematic data was collected from dogs as they walked at constant speed on a treadmill, using an infrared camera system and adhesive reflective markers applied to the pelvic limbs. Data on 5 selected variables was extracted and comparisons made between paired pelvic limbs in both CCLR and control dogs and between control and CCLR dogs. RESULTS Comparisons in CCLR dogs revealed significant differences between affected and unaffected limbs for many examined variables; the largest differences were in paw velocity and stifle angular velocity. There were highly significant differences between CCLR and control dogs when examining paired limb ratios for 4 of the variables, the largest differences were in stride length and paw velocity. CONCLUSIONS Kinematic analysis provides straightforward and objective methods for defining the lameness associated with CCLR in dogs. Paw velocity and stride length were most notably reliable and not susceptible to systematic alterations in stifle joint dynamics that might be associated with specific surgical procedures. CLINICAL RELEVANCE This study identifies several variables that can provide the objective measurements essential to evaluate the efficacy of surgical interventions for CCLR in dogs.

Feline ilial fractures: a prospective study of dorsal plating and comparison with lateral plating.

OBJECTIVE To (1) report a technique for repair of feline ilial fractures using a dorsally applied bone plate and (2) compare outcome with cats treated by a lateral plate. STUDY DESIGN Prospective study. ANIMALS Cats (n=10) with iliac fractures. METHODS Cats with ilial fractures (January 2005-December 2006) were treated by application of a dorsally applied bone plate. Immediate postoperative radiographs were compared with those taken 4-6 weeks later to assess screw loosening, screw purchase, and pelvic canal narrowing. Owners were contacted for medium-term (>3 month) follow-up. Data were compared with a report of outcome after lateral plating (LP) in 21 cats. RESULTS Mean (+/- SD) screw purchase (89 +/- 11 mm) was significantly greater (P<.01) with a dorsal plate compared with a lateral plate (33 +/- 8 mm). Significantly more screws (P<.01) were used with a dorsal plate (median, 7) compared with a lateral plate (median, 6). Significantly less postoperative pelvic canal narrowing developed in the dorsal plating group between postoperative and 4-6-week follow-up radiography compared with the LP group (2% versus 15%, P<.01). CONCLUSION Dorsal plating of feline ilial fractures results in significantly less screw loosening and pelvic canal narrowing at 4-6 weeks after surgery compared with LP. CLINICAL RELEVANCE Dorsal plating of feline iliac fractures may reduce complications associated with pelvic canal narrowing such as constipation and megacolon.

Treatment of caudal mandibular fracture and temporomandibular joint fracture-luxation using a bi-gnathic encircling and retaining device

Fractures of the caudal portion of the mandible and temporomandibular joint (TMJ) fracture-luxation can be challenging to treat with direct fixation methods. This paper describes a simple technique for the indirect treatment of caudal mandibular fracture and TMJ fracture-luxation using a subcutaneous loop of nylon leader line tunnelled around the maxilla, incisive and nasal bones, and under the mandible, placed just caudal to the canine teeth, and crimped ventral to the mandibular skin: a bignathic encircling and retaining device (BEARD). A BEARD was used to treat two immature dogs with simple, unilateral caudal mandibular fractures, six cats with unilateral injury (two with TMJ luxation, three with TMJ fracture-luxation, one with caudal mandibular fracture), and two cats with bilateral injury (comminuted caudal mandibular fracture with contralateral TMJ luxation; bilateral condylar neck fracture). The BEARD treatment failed short-term due to poor tolerance in one cat, and concurrent injuries and poor initial reduction in another cat. One cat was lost to long-term follow-up. Rostral dental occlusion was normal in six out of seven cases, and reported jaw function was normal in seven out of seven cases. The case with poor occlusion had imperfect initial reduction. Complications included dorsal nasal skin swelling or discharge, oesophagostomy tube dislodgement or blockage, BEARD loosening, and regurgitation. Treatment of uni- or bilateral caudal mandibular trauma using a BEARD can lead to clinical union, and normal rostral occlusion, provided that case selection is appropriate and immediate-post-surgical occlusion has been corrected.

Early kinematic outcome after treatment of cranial cruciate ligament rupture by tibial plateau levelling osteotomy in the dog

OBJECTIVES To establish the effect of tibial plateau levelling osteotomy (TPLO) on two selected pelvic limb kinematic variables in dogs treated for clinical cranial cruciate ligament rupture (CCLR). METHODS Thirteen dogs that had incurred CCLR and were treated by TPLO walked on a treadmill whilst kinematic data on pelvic limb paw motion were acquired using motion capture equipment. Data were subject to secondary processing using matrix analysis software and statistical analysis. RESULTS Pelvic limb stance duration significantly increased during the 12 week study period, recovering to near-normal values. Range of pelvic limb paw velocity also significantly increased but did not reach normal values by 12 weeks postoperatively. CLINICAL SIGNIFICANCE The improvement in stance duration to near normality may aid in explaining the widely-held subjective impression that TPLO frequently provides an excellent outcome in the early stages after repair of the cruciate deficient canine stifle joint. Both stance length and range of paw velocity provide useful objective measures to compare outcome following surgery for CCLR.

Modification of the cranial closing wedge ostectomy technique for the treatment of canine cruciate disease

OBJECTIVE To describe a modification of the cranial closing wedge ostectomy (CCWO) technique and to compare its efficacy to the standard technique on cadaveric specimens. METHODS The standard and modified CCWO technique were applied to eight pairs of cadaveric tibiae. The following parameters were compared following the ostectomy: degrees of plateau levelling achieved (degrees), tibial long axis shift (degrees), reduction in tibial length (mm), area of bone wedge removed (cm²), and the area of proximal fragment (cm²). RESULTS The size of the removed wedge of bone and the reduction in tibial length were significantly less with the modified CCWO technique. CLINICAL SIGNIFICANCE The modified CCWO has two main advantages. Firstly a smaller wedge is removed, allowing a greater preservation of bone stock in the proximal tibia, which is advantageous for implant placement. Secondly, the tibia is shortened to a lesser degree, which might reduce the risk of recurvatum, fibular fracture and patella desmitis. These factors are particularly propitious for the application of this technique to Terrier breeds with excessive tibial plateau angle, where large angular corrections are required. The modified CCWO is equally effective for plateau levelling and results in an equivalent tibial long-axis shift. A disadvantage with the modified technique is that not all of the cross sectional area of the distal fragment contributes to load sharing at the osteotomy.

MAGNETIC RESONANCE IMAGING FEATURES OF CANINE INCOMPLETE HUMERAL CONDYLE OSSIFICATION

Incomplete ossification of the humeral condyle (IOHC) is characterized by an intracondylar fissure located where the intercondylar physis is present in growing dogs. Its radiologic and computed tomographic features have been described but the magnetic resonance (MR) features have not been characterized. Our purpose was to further describe the range of MRappearances of IOHC, to assess the diagnostic capability of MRrelative to radiology, and to determine whether MRis able to identify the disease before a fissure forms. Thirty-eight elbow MRscans and radiographs, when available, were reviewed and divided into three groups. In Group 1 (affected elbows, n = 22), there was an intracondylar defect on MRwith variable appearance; the defect was not visible radiographically in 32% of the elbows. The main difference between Group 2 (nonaffected elbows, n = 6) and Group 3 (contralaterals to IOHC or to condylar fracture, without fissure, n = 10) was the appearance of the humeral condyle in short tau inversion recovery (STIR) sequences: all elbows in Group 2 had a homogeneous humeral condyle, whereas all but one in Group 3 were heterogeneous. One dog in Group 3 developed a complete condylar fissure 7 months after the first examination, when no evidence of an intracondylar defect had been detected. The MRappearance of IOHC is variable and a heterogeneous humeral condyle in STIR images without a clear defect may warn of the possibility for the subsequent development of a condylar fissure.

Feline talocrural luxation: A cadaveric study of repair using ligament prostheses

Currently recommended surgical techniques to treat severe biaxial feline talocrural soft-tissue injuries commonly lead to unsatisfactory outcome. Data relating to canine talocrural stabilisation may not be useful in cats due to major differences in tarsal anatomy between the species. This experimental biomechanical cadaveric study used specimens (n = 10) prepared from the distal pelvic limbs of five adult cats. The aim was to design a technique for treating talocrural luxation using suture prostheses and bone tunnels, and to investigate its suitability for use in clinical cases. Four prosthetic ligaments were placed through a series of five 1.5 mm bone tunnels. Two prostheses, the caudoproximal pair, were taut in talocrural flexion and two prostheses, the craniodistal pair, were taut in extension. The intact specimens had their range-of-motion (ROM) and stability tested, after which they were transected at the talocrural joint (simulated luxation) and repaired using the technique described. The ROM and stability of the repaired specimens were tested and compared to the intact specimens. The repaired specimens had comparable stability to the intact specimens, although the ROM was different (p <0.05) in six of 16 positions (p <0.003125). These corresponded to the positions where the lateral prostheses were taut. The repair technique described may be useful in the treatment of talocrural luxation, as it is low-profile in an area of limited soft-tissue cover, allows anatomic reduction, restores normal talocrural joint stability and near-normal tarsal ROM.

Complications of lateral plate fixation compared with tension band wiring and pin or lag screw fixation for calcaneoquartal arthrodesis. Treatment of proximal intertarsal subluxation occurring secondary to non-traumatic plantar tarsal ligament disruption in dogs.

OBJECTIVE To compare complication rates and the outcomes of these complications after lateral plate fixation with figure-of-eight tension-band-wire and pin or lag screw fixation for arthrodesis of the calcaneoquartal joint, following non-traumatic disruption of the plantar tarsal ligament in dogs. METHODS Data were collected retrospectively from five UK referral centres. Diplomate specialists and their residents performed all procedures. Referring veterinarians were contacted for long-term follow-up. RESULTS Seventy-four procedures were undertaken in 61 dogs. There were 58 arthrodeses in the lateral plate group (Plate), nine in the pin and tension-band-wire group (Pin), and seven in the lag screw and tension-band wire-group (Screw). Compared to Plate (17%), further surgical intervention was required more frequently following Pin (56%, OR = 3.2) or Screw (43%, OR = 2.5) fixation. Clinical failure of arthrodesis occurred less frequently with Plate (5%) compared with Screw (43%, OR = 8.6) and Pin fixation (22%, OR = 4.4). Cases managed with external coaptation postoperatively were more likely to suffer from postoperative complications (OR = 2.2). CLINICAL SIGNIFICANCE Lateral plating was associated with fewer postoperative complications than pin and tension-band-wire fixation for arthrodesis of the calcaneoquartal joint in dogs with non-traumatic disruption of the plantar tarsal ligament.

Salter-Harris type III fractures of the distal humerus in two dogs

Salter-Harris type III fractures of the distal humerus in a four-month-old male Labrador Retriever and a male crossbreed dog (estimated to be 3.5-months-old) are reported. Both fractures were treated with open reduction and interfragmentary compression by lag screw fixation. Both fractures healed and full limb use was regained at four weeks postoperatively. The occurrence of this unusual fracture type may be related to the physeal closure pattern of the distal humeral physis, and a different mechanism of injury compared to the more common Salter-Harris type IV fracture seen in this region.

Unusual presentation of bilateral stifle osteochondritis dissecans in two labrador retrievers

There are few published reports of CT findings for the diagnosis of stifle osteochondritis dissecans (OCD) in the dog. This report describes the radiographic and multidetector CT (MDCT) findings of two cases with bilateral stifle osteochondrosis and OCD lesions. In both cases, radiographs did not provide a complete picture of the pathology and CT was needed for a definitive diagnosis. In case 1, CT showed bilateral defects on the caudomedial part of the lateral femoral condyles with joint mice within the cranial right stifle joint. In case 2, CT showed large bilateral joint mice within the intercondylar fossa originating from the medial aspect of the lateral femoral condyles as well as a defect on the right medial femoral condyle. MDCT provided an accurate diagnosis in both these cases and facilitated surgical planning.