Rob Pettitt

Radiographic and ultrasonographic changes of the patellar ligament following tibial tuberosity advancement in 25 dogs.

INTRODUCTION Patellar ligament thickening is a recognized response following osteotomy of the proximal tibia as a treatment for cranial cruciate disease. In humans this is seen as a response to increased loading, but the reason for this thickening in dogs is unclear. A prospective study was undertaken to assess the degree and frequency of patellar ligament desmopathy in 25 consecutive cases undergoing tibial tuberosity advancement (TTA). OBJECTIVES To determine the incidence of patellar ligament thickening following TTA. METHODS Consecutive cases undergoing TTA had ultrasonographic and radiographic measurements performed of the patellar ligament, at multiple positions on the ligament. This was performed at the time of surgery, and at six weeks and six months (ultrasound only) following surgery. The radiographic measurements were performed by two reviewers who were blinded to the timeframe of each image. RESULTS There was great variation in both the incidence and degree of thickening of the ligament. Fifty percent of the cases showed no changes in the thickness of the patellar ligament. A clinical pain response was not associated with patellar ligament thickening. No statistically significant variables which predicted the development of patellar ligament thickening were identified . CLINICAL SIGNIFICANCE The presence of signs of patellar ligament thickening is of questionable clinical significance and is probably an incidental finding.

Investigation and management of canine osteoarthritis

Lameness in dogs will be a familiar part of any small animal practitioners caseload. Osteoarthritis is a common cause for this lameness, although it is often secondary to a primary inciting cause; so treatment and management may need to address the primary inciting cause as well as the pain associated with the arthritis. Management of the condition involves a combination of medical and surgical options, and weight management can often be crucial in reducing pain and improving patient mobility. In this article, Rob Pettitt and Alex German explore the multifactorial elements in both investigating and managing this condition in dogs.

Effect of surgical technique on radiographic fusion of the anconeus in the treatment of ununited anconeal process

OBJECTIVES The aim of this study was to determine if internal fixation of the anconeus combined with a proximal ulnar osteotomy was more likely to result in fusion of the anconeus to the ulna compared with a proximal ulnar osteotomy alone. METHODS A total of 12 orthopaedic referral clinics reviewed their clinical databases for cases of ununited anconeal process. Demographic and clinical parameters were collected along with radiographic follow-up at a minimum of four weeks. Cases treated with proximal ulnar osteotomy alone were compared with those treated with proximal ulnar osteotomy + internal fixation. Both groups were compared for background and disease variables. We tested for an association between treatment method and whether radiographic anconeal union had occurred. RESULTS A total of 47 elbows (44 dogs) were identified. Of these, 28 cases (average age 7.6 months) were treated with proximal ulnar osteotomy (of which eight were stabilised with an intramedullary pin) alone. Nineteen cases (average age 7.1 months) were treated with proximal ulnar osteotomy + internal fixation. The two groups were not significantly different in age (P=0.638, Mann-Whitney U test). Fourteen of 28 cases with proximal ulnar osteotomy alone displayed anconeal union at follow-up compared with 16 of 19 cases of proximal ulnar osteotomy + internal fixation, and this difference was statistically significant (P=0.029, Fishers exact test). CLINICAL SIGNIFICANCE These data suggest that use of a lag screw to stabilise and compress the ununited anconeal process in addition to proximal ulnar osteotomy produces a better radiographic outcome. It is argued that radiographic union of the anconeus is likely to be associated with better long-term clinical outcome but further studies are required to confirm this.

The use of transarticular external skeletal fixation in the management of failed tibial tuberosity transposition in five dogs

The management of tibial tuberosity fracture-avulsion after tibial tuberosity transposition can be challenging. Implants must be able to resist the strong distractive force of the quadriceps mechanism, yet implant size is limited by the amount of tuberosity bone stock available. Revision fixation is compromised further by fragmentation of the tubercle. Five stifle joints had temporary transarticular external skeletal fixators applied to manage complications of tibial tuberosity transposition. Fracture reduction was confirmed in four out of five tibial tuberosity fractures. Frames were in place for a mean of 44 days. Frame associated complications occurred in four out of five limbs, the most common being pin tract discharge and associated osteolucency. All frame-associated complications resolved. Long-term follow-up information was available for three of the five animals at 13 to 18 months after frame removal. All three owners reported occasional lameness, but this was attributed to concurrent orthopaedic disease. Transarticular external skeleton fixation protects internal fixation techniques, and good limb function was achieved in most cases. Transarticular external skeleton fixation can be successfully used to augment repair of tibial tuberosity fracture after tibial tuberosity transposition.

Ex vivo kinematic studies of a canine unlinked semi-constrained hybrid total elbow arthroplasty system

OBJECTIVES Introduction of the Sirius® canine total elbow arthroplasty system, and presentation of the results of a passive range-of-motion analysis based on ex vivo kinematic studies pre-and post-implantation. MATERIALS AND METHODS Thoracic limbs (n = 4) of medium sized dogs were harvested by forequarter amputation. Plain orthogonal radiographs of each limb were obtained pre- and post-implantation. Limbs were prepared by placement of external fixator pins and Kirschner wires into the humerus and radius. Each limb was secured into a custom-made box frame and retro-reflective markers were placed on the exposed ends of the pins and wires. Each elbow was manually moved through five ranges-of-motion manoeuvres. Data collected included six trials of i) full extension to full flexion and ii) pronation and supination in 90° flexion; a three-dimensional motion capture system was used to collect and analyse the data. The Sirius elbow prosthesis was subsequently implanted and the same measurements were repeated. Data sets were tested for normality. Paired t-tests were used for comparison of pre- and post-implantation motion parameters. RESULTS Kinematic analysis showed that the range-of-motion (mean and SD) for flexion and extension pre-implantation was 115° ± 6 (range: 25° to 140°). The range-of-motion in the sagittal plane post-implantation was 90° ± 4 (range: 36° to 130°) and this reduction was significant (p = 0.0001). The ranges-of-motion (mean and SD) for supination and pronation at 90° were 50° ± 5, whereas the corresponding mean ranges-of-motion post-implantation were 38° ± 6 (p = 0.0188). CONCLUSION Compared to a normal elbow, the range-of-motion was reduced. Post-implantation, supination and pronation range-of-motion was significantly reduced at 90° over pre-implantation values. CLINICAL RELEVANCE These results provide valuable information regarding the effect of the Sirius system on ex vivo kinematics of the normal canine elbow joint. Further, this particular ex vivo model allowed for satisfactory and repeatable kinematic analysis.

Peak Vertical Force and Vertical Impulse in Dogs With Cranial Cruciate Ligament Rupture and Meniscal Injury

OBJECTIVE To compare the peak vertical force (PVF) and vertical impulse (VI) in dogs with naturally occurring cranial cruciate ligament (CCL) disease with or without concurrent meniscal injury. STUDY DESIGN Prospective case series. STUDY POPULATION Client-owned dogs with naturally occurring CCL disease. METHODS Dogs with hind limb lameness because of CCL disease that required surgery underwent force plate gait analysis. Force plate analysis was performed at a walking gait (speed 1-1.3 m/s; acceleration ± 0.5 m/s(2)) and data were analyzed using commercial proprietary software. Meniscal injury was diagnosed either by mini-arthrotomy or arthroscopy. The primary outcome was PVF and the secondary outcome was VI. Comparisons were made between dogs with or without meniscal injury, and dogs with partial or complete CCL rupture. RESULTS Forty dogs were included. Meniscal injury was present in 18/40 dogs (45%). PVF (P = .003) and VI (P = .01) were significantly lower in dogs with meniscal injury than in dogs without meniscal injury. CONCLUSION Dogs with CCL disease and medial meniscal injury had significantly reduced PVF and VI.

Bilateral angular carpal deformity in a dog with craniomandibular osteopathy

A four-month-old West Highland White Terrier was presented to the Small Animal Teaching Hospital at the University of Liverpool with the complaint of a bilateral angular carpal deformity. A 20° valgus deformity was present in both thoracic limbs, centred on the distal radial physes. Both distal ulnas were grossly thickened and there was concomitant thickening of the rostral mandible and calvarium. The dog exhibited signs of resentment on palpation of the mandible and signs of pain were elicited on flexion and extension of both elbow joints. No signs of pain were evident on palpation of the ulnas or calvarium. Radiographic images of both ulnas showed marked amorphous periosteal new bone formation. The distal ulnar physes were closed centrally and both elbow joints had humeroulnar subluxation. Radiographic changes to the calvarium and mandibular rami were consistent with a diagnosis of craniomandibular osteopathy. A bilateral ulna ostectomy was performed to correct the angular limb deformity and elbow subluxations. Histology of the ostectomised pieces showed changes consistent with craniomandibular osteopathy.

Pneumorrhachis in a rottweiler

An 8·5-year-old, female, neutered, Rottweiler was presented for investigation of progressive ataxia of one week duration. Proprioception was absent in the left pelvic limb and reduced on the right, thoracolumbar hyperalgesia was evident and pelvic limb segmental spinal reflexes were normal. Magnetic resonance imaging (MRI) demonstrated a spherical region of signal void compressing the spinal cord between the fifth and sixth thoracic vertebrae and several non-compressive degenerate intervertebral discs. Computed tomography (CT) of the region confirmed the findings and identified the lesion as gas. A dorsolateral hemilaminectomy was performed to decompress the spinal cord and achieved complete resolution of the clinical signs on examination after 3 months. This is the first known reported case of spontaneous pneumorrhachis in a veterinary patient.

Rigid Endoscopy: arthroscopy

The use of rigid endoscopy for joint surgery has been the standard in human and equine orthopaedics for over three decades. The use of arthroscopy in small animals for the treatment and diagnosis of joint diseases has increased dramatically in the last 10-15 years due to advances in equipment and techniques. Numerous benefits of arthroscopy have been cited, including improved viewing and magnification of lesions, decreased operative time, minimal joint trauma, and lower patient morbidity. There is, however, a considerable learning curve, and these advantages can only be achieved through practice and an understanding and correct selection of arthroscopic equipment. This chapter provides am introduction to small animal arthroscopy through its indications, ancillary procedures, instrumentation and current applications.

Evaluation of variables influencing success and complication rates in canine total hip replacement: results from the British Veterinary Orthopaedic Association Canine Hip Registry (collation of data: 2010–2012)

The objective of this study was to assess the variables associated with complications of total hip replacement (THR) and report owner-assessed outcomes. Entries into the British Veterinary Orthopaedic Association-Canine Hip Registry (BVOA-CHR) between September 2011 and December 2012 were reviewed separately and in conjunction with previous data (January 2010–August 2011). An outcomes assessment questionnaire was used to collect data from owners. Incidences of surgeon-reported and owner-reported complications were 8.2 per cent and 4.3 per cent, respectively. THR using the BioMedtrix BFX cup/stem prosthesis had a greater incidence of complications compared with THR using the BioMedtrix CFX cup/stem prosthesis (P=0.002); complications were 4.48 times more likely when using the BioMedtrix BFX cup/stem prosthesis versus the BioMedtrix CFX cup/stem prosthesis. THR using the BioMedtrix BFX cup/stem prosthesis had a higher incidence of complications compared with THR using a hybrid prosthesis (BioMedtrix BFX cup/CFX stem, BioMedtrix CFX cup/BFX stem) (P=0.046); complications were 2.85 times more likely when using the BioMedtrix BFX cup/stem prosthesis versus a hybrid prosthesis. In 95 per cent of cases, owner satisfaction with the outcome of THR was ‘very good’ or ‘good’. Complication rates from the BVOA-CHR are similar to previous studies. The data suggest that prosthesis type is associated with complication rate, with BioMedtrix BFX (circa 2012) having a high short-term complication rate.