Plate failure by bending following tibial fracture stabilisation in 10 cats.

OBJECTIVE: To describe the clinical findings and management of tibial fractures in cats in which osteosynthesis failed due to plate bending. METHODS: Case records and radiographs of cat tibial fracture repairs from five referral centres were reviewed for signalment and to assess incidence of plate failure by bending. Cats that sustained plate bending following plate or plate-rod fixation were reviewed for fracture configuration, repair method, initial postoperative and postfailure tibial alignment, revision treatment and outcome. RESULTS: The incidence of plate bending in cat fractures managed with plate and plate-rod fixation in the four referral centres where the overall number could be established was 13% (8/60). In the 10 cats in which plates bent, initial fractures were generally oblique or spiral with mild comminution and located in the middle or distal third of the tibia. Mean time to implant failure was 24 days (range 2 to 56 days). Mean tibial valgus angle increased from 12·9° to 30·9° following bending of the plate. Short-term outcome following revision surgery using orthogonal plating or stacked medial plates was favourable with improvement in tibial valgus in all five fractures with follow-up data. CLINICAL SIGNIFICANCE: Plate bending following tibial fracture stabilisation in these 10 cats resulted in tibial valgus deformation. Consideration of plate and/or intramedullary rod selection and application should be given to avoid a plate strain environment that exceeds the yield point of the plate.

Treatment of cranial cruciate ligament rupture in the feline stifle. Biomechanical comparison of a standard fabella-tibial suture and lateral sutures placed between quasi-isometric points.

OBJECTIVE: To determine whether a lateral suture placed with bone anchors between quasi-isometric points in a cat is superior to a standard fabella-tibial suture for the stabilization of cranial cruciate ligament (CrCL) rupture compared to an intact stifle joint. STUDY DESIGN: Biomechanical cadaveric study. METHODS: Six stifle joints with intact cruciate ligaments from three skeletally mature cats were placed in a loading mounting set and tested with axial loads of 20N and 60N at three different joint angles (75°,130° and 160°). The procedure was repeated with a transected CrCL; a stabilized stifle joint after a combination of three lateral suture techniques (fabella-tibial suture technique [SFT]; femoro-tibial suture technique 1 [FTS-1] and femoro-tibial suture technique 2 [FTS-2]). Radiographic examination of the relative position of the tibia to the fixed femur was compared. RESULTS: Stabilization of the stifle joint with lateral sutures had comparable stability to the intact specimens in the cranio-caudal direction (p = 0.2) but not in the proximo-distal direction for the SFT (p = 0.04) and FTS-2 technique (p = 0.03). There was no significant difference between the three stabilization techniques (p >0.05). CLINICAL SIGNIFICANCE: Lateral sutures placed with bone anchors at quasi-isometric points performed better than SFT and FTS-2 in stabilizing the feline stifle after CrCL rupture in the proximo-distal plane. Biomechanical stability in the cranio-caudal plane after placement of a lateral suture across the feline stifle was similar to the intact CrCL.

Inter- and intraobserver agreement in interpretation of CT features of medial coronoid process disease.

OBJECTIVES: To evaluate inter- and intraobserver reliability of the assessment of computed tomography features commonly used in the identification and classification of medial coronoid process disease and to assess inter- and intraobserver variability in the identification of the percentage ulna sclerosis from single transverse computed tomography images. METHODS: Eight observers, on two occasions, reviewed 84 standardised single transverse computed tomography images acquired at the level of the apex of the medial coronoid process. Observers assessed: medial coronoid process disease, coronoid process fragmentation, osteophytes, sclerosis grade and sclerosis delineation with normal bone defined using a sclerometer. Cohen's kappa and intraclass correlation coefficient were calculated. RESULTS: Inter-observer agreement was fair to moderate for identification of computed tomography changes consistent with medial coronoid process disease, moderate to almost perfect for fragmentation, and moderate for osteophyte detection. Agreement was poor for sclerosis grading. Percentage sclerosis measured with a sclerometer had moderate to almost perfect inter- and intraobserver agreement. CLINICAL SIGNIFICANCE: These findings suggest that subjective assessment of computed tomography images is less repeatable than more quantitative methods.

Patellar ligament rupture in the dog: repair methods and patient outcomes in 43 cases.

The medical records of dogs receiving surgery for unilateral patellar ligament rupture between 1999 and 2012 at 12 multidisciplinary referral centres were reviewed. Forty-three cases were identified; 26 were traumatic in origin; almost one-third were iatrogenic, of which over three-quarters occurred as a complication following surgical stabilisation of patellar luxation. Treatment involved primary reapposition of the ligament (36 cases). The repair was protected by circumpatellar and/or transpatellar loop(s) of orthopaedic wire, nylon, polypropylene or polydioxanone suture (34 cases). Wire loops were more likely to require surgical removal compared with loops of other materials (P=0.0014). The stifle joint was immobilised postoperatively by the applications of a transarticular external skeletal fixator (taESF) in 17 cases and by external coaptation (EC) in 8 cases; in 18 cases, no postoperative joint immobilisation was provided. Complications specific to the method of immobilisation occurred in seven of the cases with taESF and six of the cases with EC. Revision surgery to address failure of repair was required in five cases. Outcome was classified as acceptable or good in over three-quarters of the cases (31/40) and poor in less than a quarter (9/40). These data highlight patellar ligament rupture as a complication of surgical stabilisation of patellar luxation.

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.

Long bone fracture as a complication following external skeletal fixation: 11 cases.

OBJECTIVES: To report on a series of dogs and cats with long bone fractures that occurred as a direct consequence of linear external skeletal fixation (ESF) application. METHODS: Retrospective study. Data from the medical records and radiographs of canine (n = 4) and feline (n = 7) cases were collected from three referral and three first opinion practices in the UK (1999 to 2011). RESULTS: Long bone fractures occurred following the application of linear ESF either while the ESF was in situ or after removal. All fractures occurred through either a pin tract or an empty drill hole. Pins associated with ESF-related fracture tended to be in the higher end of the recommended size range. The majority of cases had additional complicating factors such as multiple injuries, revision surgery, poor owner compliance with postoperative exercise restriction and the presence of empty drill holes. CLINICAL SIGNIFICANCE: In cases with features that could complicate outcome, careful attention should be paid to recommendations for ESF application. Leaving empty drill holes is suboptimal. The retrospective nature of the study, low numbers of, and diversity amongst, cases should be taken into consideration when interpreting the results from this study.

Healing of patellar fractures in two kittens.

Two kittens aged between four and five months were presented having sustained patellar fractures. In both cases, healing was subsequently documented radiographically; this has not been reported previously in the literature. One kitten had bilateral patellar fractures - the symptomatic right stifle was treated with a pin and tension-band-wire which later failed, at which point partial patellectomy was performed. The fracture of the left patella was minimally displaced and was treated conservatively. A radiograph of the left patella taken eleven months after initial presentation showed complete healing of the fracture. The second case was treated surgically with a circumferential wire; healing of the fracture was demonstrated radiographically at twelve weeks postoperatively. Radiographic images taken five weeks postoperatively had shown some narrowing of the fracture gap. These two cases demonstrate that bony union of patellar fractures can be documented, given a long enough duration of radiographic follow-up; circumferential wire was an effective treatment in a displaced fracture, and conservative treatment resulted in complete healing of a minimally displaced fracture.

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.

Risk factors for medial meniscal injury in association with cranial cruciate ligament rupture.

OBJECTIVES: To determine the significant risk factors for medial meniscal injury in naturally occurring cranial cruciate ligament rupture and to quantify the risk using multivariate analysis. METHODS: A retrospective case control study was performed of dogs that had undergone surgery for cranial cruciate ligament rupture. Data recorded included patient signalment (age, breed and sex), the duration of the lameness, the extent of the cranial cruciate ligament rupture (complete or partial) and the condition of the medial meniscus. Logistic regression was used to analyse the relationship between these variables and tears in the medial meniscus. RESULTS: One hundred and sixty-one of 443 stifles (36·3%) in 366 dogs had a medial meniscal tear. The risk of a medial meniscal tear was increased by 12·9 times in association with complete cranial cruciate ligament rupture (OR 12·9; 95% CI 6·8 to 24·2), by approximately 2·6% for each additional week of lameness (OR 1·026; 95% CI 1·009 to 1·043) and by approximately 1·4% for each additional kilogram of bodyweight (OR 1·014; 95% CI 1·000 to 1·028). Golden retrievers and Rottweilers were at increased risk and West Highland white terriers were at reduced risk of medial meniscal tears compared with Labrador retrievers. CLINICAL SIGNIFICANCE: To minimise the risk of medial meniscal tears, surgical stabilisation should not be unnecessarily delayed.

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.

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, Fisher's 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.

Transverse stress fractures of the proximal tibia in 10 cats with non-union patellar fractures.

Ten cats with a mean age of eight years and five months had suffered proximal transverse tibial fractures; in four of them both tibiae had fractured at different times. All the cats also had bilateral non-union patellar fractures, and nine of them had evidence of fractures elsewhere, including acetabular, ischial, humeral condylar and rib fractures, which had occurred before or after the tibial fractures. All the tibial fractures were proximal and transverse. Radiographically, there was thickening and sclerosis of the cranial cortex adjacent to and at the level of the fracture, changes that were compatible with stress fractures. The outcome of repair of the tibial fracture was known in nine of the cats; eight of them healed and one resulted in a non-union. Two of the cats were euthanased as a direct result of the fracture or complications with the repair.

Long-term results of transarticular pinning for surgical stabilisation of coxofemoral luxation in 20 cats.

OBJECTIVES: The objective of this study was to describe initial and long-term results of open reduction and transarticular pinning for treatment of coxofemoral luxations in cats. METHODS: Cats were treated by open reduction and transarticular pinning for coxofemoral luxation over a five year period at two institutions. Follow-up assessment included orthopaedic examination, radiography and owner questionnaires. RESULTS: Twenty cats were included in the study (14 males and six females). One cat was affected bilaterally. Mean time to follow-up was 21 months. Seventeen joints were stabilised with a 1.6 mm pin, three with 2.0 mm pins and a 1.2 mm pin was used in the remaining joint. An Ehmer sling was not utilised in any case. All transarticular pins except one were removed (mean 3.5 weeks), with all hips still in reduction The overall success rate was 77 per cent, with two reluxations and one resorbed femoral head noted on radiographs of 13 joints followed long term. All 20 owners reported good to excellent long-term functional outcome for their cats. CLINICAL SIGNIFICANCE: Results from this study indicate that transarticular pinning for stabilisation of coxofemoral luxation in cats can provide a good long-term outcome without sacrificing the integrity of the coxofemoral joint.

Survey of 52 fractures of the patella in 34 cats.

Stress fractures of the patella were diagnosed in 34 cats with a mean age of two years and five months. Eighteen of the cats had bilateral fractures with a median interval of three months between fractures. All the fractures were transverse and occurred in the proximal aspect or base of the patella with no evidence of trauma. In 43 of the patellae there was radiographic evidence of sclerosis. Repairs with a pin and tension band in 18 cats resulted in a further fracture or failure of fixation in 86 per cent of the cases that were followed up. Ten of the cats had suffered fractures of other bones at different times to the patellae fractures. In the majority of the cats the fracture formed a functional non-union but some cats remained stiff and lame.

Feline combined diaphyseal radial and ulnar fractures. A retrospective study of 28 cases.

Feline combined diaphyseal radial and ulnar fractures were reviewed in a retrospective study of cases that were admitted to two university teaching hospitals. A high incidence of complications was noted, with 6/26 (23.1%) of cases requiring revision surgery. Open fractures were significantly more likely to require revision surgery. The two main repair methods were external skeletal fixation (ESF) or radial plating. The success rate was greater for radial plating, with only 1/10 (10%) cases requiring revision versus 4/14 (28.6%) for ESF. However, ESF tended to be applied to the more complicated fractures. Stabilisation of both bones proved to be an effective repair strategy with only 1/8 cases (12.5%) requiring revision versus 5/18 cases (27.8%) where only one bone was stabilised. Synostoses and radiohumeral luxation were noted as complications associated with the fractures stabilised by ESF. Final limb function following recovery was assessed as 'good' or 'excellent' in 93.3% of cases.

A biomechanical comparison of six different double loop configurations for use in the lateral fabella suture technique.

Six different double loop configurations which could be applied to the lateral fabella suture (LFS) technique were subjected to in vitro mechanical testing. Three double loop, single strand and three double loop, double strand configurations were tested. The strongest configuration, with a significantly higher mean ultimate load and load at yield, was the interlocking loop configuration. This is a novel configuration which has not previously been reported. The three double loop, single strand configurations all had higher mean ultimate loads than the double loop, double strand configurations. The double strand group with uneven loop length performed very poorly, with significantly lower mean stiffness and ultimate load than all of the single strand groups. This group also developed unacceptably high levels of elongation during high level cyclic loading.

Traumatic fracture of the patella in 11 cats.

Traumatic patellar fracture in cats mainly occurred in male neutered cats with an average age of four years, six months and a mean weight of 4.8 kg. Patellar fractures were concurrent with long bone fractures and cruciate ligament rupture or occurred after gunshot. The patella luxated medially or laterally in four cats. Fracture fragments were usually small, either from the proximal pole (base) or distal pole (apex) or longitudinal fragments. Treatment was by fragment excision when the fragment was small or by reconstruction with pins and wires when fractures were comminuted. The outcome in six cats was reported as 'good' to 'normal' and three cats were 'improving' or had 'mild' intermittent lameness at the last follow up.

Radiographic and clinical features of carpal varus associated with chronic sprain of the lateral collateral ligament complex in 10 dogs.

Lameness associated with carpal varus deformity was recognised in 10 dogs, eight of which were Dobermann Pinschers. The dogs had a mean age of seven years and nine months. Carpal varus was usually bilateral with concurrent carpal hyperflexion and pronation. Carpal varus was present prior to the onset of lameness in four cases. With stress radiography the median angle of varus deviation in all carpi was 14.6 degrees , and an increase in the size of the ulnar /ulnar carpal bone joint space was seen in six of the seven dogs. Radiographic changes included: enthesophyte formation at the proximolateral aspect of metacarpal V, periarticular soft tissue swelling, especially lateral, bone proliferation at the carpometacarpal joint I and enthesophyte formation at metacarpophalangeal joint V. Four dogs were admitted for problems other than carpal varus and lameness was not treated. Five dogs were treated with nonsteroidal anti-inflammatory drugs, but lameness was not completely resolved and became exacerbated with exercise. One dog was successfully treated by pancarpal arthrodesis.

Patellar luxation as a complication of surgical intervention for the management of cranial cruciate ligament rupture in dogs. A retrospective study of 32 cases.

This retrospective study identified 32 cases of patellar luxation which occurred as a complication of surgical intervention for cranial cruciate ligament rupture (CCLR). The complication was recorded mostly in larger (>/=20 kg) dogs with the Labrador Retriever being the most common breed. The complication followed extra-capsular, intra-capsular and tibial plateau levelling surgery. The mean time from CCLR surgery to the diagnosis of patellar luxation was 14 weeks. The incidence of patellar luxation occurring as a complication of surgical intervention for CCLR was 0.18% of all CCLR corrective procedures. Corrective surgery for patellar luxation was successful in 79% of stifles. The patellar reluxation rate was significantly lower (p = 0.0007) when at least one corrective osteotomy (tibial tuberosity transposition, femoral trochlear sulcoplasty or tibial plateau levelling osteotomy with tibial axial re-alignment) was performed (35%), compared to when corrective osteotomy was not performed (100% patellar reluxation rate). When performing corrective surgery for patellar luxation following CCLR surgery, at least one corrective osteotomy should be performed in order to reduce the patellar reluxation rate. The correction of patellar luxation following surgery for CCLR is challenging and carries a significant rate of failure.