Stabilisation of metacarpal or metatarsal fractures in three dogs, using circular external skeletal fixation

Outcomes of 15 dogs and two cats with metabone fractures treated with fluoroscopically guided normograde metabone pinning

OBJECTIVE

To report the outcomes of 15 dogs and two cats with metabone fractures treated with fluoroscopically guided normograde metabone pinning (FGNMP).

STUDY DESIGN

Retrospective case series.

ANIMALS

A total of 15 client owned dogs and two cats with 57 metabone fractures.

METHODS

Description of FGNMP and reporting of the following data: signalment, pre- and postoperative radiographs, intramedullary pin diameter used, anesthesia, surgery and coaptation times, duration to normal weightbearing and bone union, postoperative care and complications.

RESULTS

Median surgery time was 54 min (range: 26-99), median duration of coaptation was 14 days (range: 1-5 weeks), median time to normal weightbearing was 16 days (range: 2-45) and median time to bone union was 6 weeks (range: 4-12). All cases had at least 12 months of post-surgical follow-up with a median follow-up of 18 months (range: 12-70). No major complications occurred. Mild radiographic changes associated with subchondral bone sclerosis were noted on follow-up radiographs in 13/57 fractures. All cases returned to normal gait and full (15) or acceptable (2) function.

CONCLUSION

In this study, FGNMP was an effective and safe technique for metabone fracture repair, requiring only short-term external coaptation in most patients. Time to bone union and return to normal function compared favorably to previously reported techniques.

CLINICAL RELEVANCE

Fluoroscopically guided normograde metabone pinning provides an alternative technique for treatment of metabone fractures.

Treatment of Medial Instability of the Carpometacarpal and Tarsometatarsal Joints Using the Isolock® System in Two Dogs

This case report describes a novel procedure using the Isolock Intrauma® implant system for treating medial instability of the carpometacarpal and tarsometatarsal joints, as demonstrated in in two dogs. A 9-year-old spayed female Spanish greyhound presented with a non-weight-bearing right hindlimb following a trauma. The clinical and radiological findings confirmed medial tarsometatarsal instability consistent with valgus deviation of the tarsus and the opening of the joint line on the medial aspect from the first to the third tarsometatarsal joints. A 4-year-old female Drahthaar presented with a non-weight-bearing left forelimb, swelling of the carpus and valgus instability. Radiological examination revealed a widening of the spaces between the intermedioradial carpal bone, second carpal bone and metacarpal bone II, confirming the medial carpometacarpal instability. In both cases, the Isolock system, an implant including ultra-high-molecular-weight polyethylene suture (UHMWPE), was used to reinforce the medial joint structures. Minor short-term complications were observed, such as swelling of the tarsal surgical site and hyperextension of the carpus, but these resolved spontaneously. No lameness or major complications were reported five months postoperatively. Carpometacarpal and tarsometatarsal instabilities are rare diseases in dogs as compared to subluxations of the other joints of the carpus and tarsus. There are no previous reports regarding the use of a UHMPWE implant for the treatment of these rare joint injuries, though the present case report suggests the validity and efficacy of the Isolock Intrauma® implant for restoring carpal and tarsal stability and preserving joint mobility.

Comparison of post-operative outcomes after open or closed surgical techniques to stabilize metacarpal and metatarsal fractures in dogs and cats

BACKFROUND

Treatment options for metacarpal/metatarsal fractures include conservative and surgical management. The aim of this study is to determine whether there is any significant difference in healing and complication rates, between open and closed treatment. Medical records of dogs and cats with metacarpal/metatarsal fractures with complete follow-up were retrospectively reviewed. Patients were allocated in two groups: open or closed stabilization. Minor and major complications were recorded and compared. Fracture healing was classified as good, delayed and non-union, and it was statistically compared.

RESULTS

Sixty-three patients (35 dogs and 28 cats) were included. Thirty-one were treated with an open approach and 32 by a closed stabilization. Regarding fracture healing a significantly higher proportion of delayed healing/non-union was found in the closed group (12/32 vs 2/31). Regarding postoperative complications, a significantly higher number of animals in the open group did not develop any complications (12/31 vs 3/32). A significantly higher proportion of minor complications were reported in the closed group (27/32 vs 12/31). However, a higher number of major complications was reported in the open group (7/31 vs 2/32) although this was not statistically significant. Fracture malalignment was significantly more prevalent in patients undergoing closed stabilization (11/32 vs 2/31).

CONCLUSION

According to the results, better healing, fracture alignment and a lower complication rate are found when fractures are stabilised with an open technique. However, other factors such as configuration of the fracture, soft tissue involvement, patient´s character and client´s situation would also need to be taken into account in the decision of stabilization technique.

Recommendations for design and conduct of preclinical in vivo studies of orthopedic device-related infection

Orthopedic device-related infection (ODRI), including both fracture-related infection (FRI) and periprosthetic joint infection (PJI), remain among the most challenging complications in orthopedic and musculoskeletal trauma surgery. ODRI has been convincingly shown to delay healing, worsen functional outcome and incur significant socio-economic costs. To address this clinical problem, ever more sophisticated technologies targeting the prevention and/or treatment of ODRI are being developed and tested in vitro and in vivo. Among the most commonly described innovations are antimicrobial-coated orthopedic devices, antimicrobial-loaded bone cements and void fillers, and dual osteo-inductive/antimicrobial biomaterials. Unfortunately, translation of these technologies to the clinic has been limited, at least partially due to the challenging and still evolving regulatory environment for antimicrobial drug-device combination products, and a lack of clarity in the burden of proof required in preclinical studies. Preclinical in vivo testing (i.e. animal studies) represents a critical phase of the multidisciplinary effort to design, produce and reliably test both safety and efficacy of any new antimicrobial device. Nonetheless, current in vivo testing protocols, procedures, models, and assessments are highly disparate, irregularly conducted and reported, and without standardization and validation. The purpose of the present opinion piece is to discuss best practices in preclinical in vivo testing of antimicrobial interventions targeting ODRI. By sharing these experience-driven views, we aim to aid others in conducting such studies both for fundamental biomedical research, but also for regulatory and clinical evaluation. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:271-287, 2019.

Long-term prognosis of metacarpal and metatarsal fractures in dogs

Objectives: Lameness after metacarpal and metatarsal fractures in dogs is reported to occur with an incidence of 18% to 70%. On the basis of long-term results, the prognosis of these injuries was re-evaluated retrospectively.

Methods: Medical records of 100 dogs with complete clinical and radiographic follow-up examinations after an average of four years (4 months – 14 years) were evaluated. According to their treatment, patients were allocated to three groups (Group 1 = conservative, Group 2 = surgical, Group 3 = combined). Assessment included complications during the healing period and the final radiographic and functional outcome, which was statistically compared for differences between groups (Fisher exact test, exact Wilcoxon-Mann-Whitney test). Further, risk factors for each bone were analyzed (stepwise, multiple logistic regression model). In 15 dogs, kinetic data (relative stance phase, peak vertical force and impulse) were investigated by computed gait analysis.

Results: Complications were observed in 11 of 67 (16%) conservatively, in three of 25 (12%) surgically, and in three of eight (37%) conservatively and surgically treated dogs. Overall frequency of lameness evaluated by visual clinical assessment was three percent. Frequency of osteoarthritis and nonunion was also low, accounting for three percent and one percent respectively, although healing of mainly single-bone fractures resulted in malunions in 14% radiographically. Synostoses were found in 19% of patients, and significantly more frequent in surgically treated dogs. A higher risk of complications was identified for metatarsal compared to metacarpal fractures. Further, an increased risk for complications was detected for a higher degree of displacement and instability.

Clinical significance: According to the longterm results found in this study, the prognosis for metacarpal and metatarsal fractures is better than reported in the literature to date. With the reservation that more severe injuries are generally treated surgically, and these fractures more frequently developed synostosis, no significant difference could be detected between conservative and surgical treatment.

[Dowel pinning for metacarpal and metatarsal fractures in dogs]

OBJECTIVE

To evaluate a dowel pinning technique for metacarpal and metatarsal fractures in dogs.

MATERIAL AND METHODS

Medical records of 13 dogs with complete clinical and radiographic follow-up examinations after a median observation time of 5 months were evaluated retrospectively. Assessment included fracture data, number of stabilized bones versus number of fractured bones and parameters of internal fixation including postoperative axial alignment and position of implants assessed on serial radiographs. Complications during the healing period and the final radiographic and functional outcome were analysed in relation to the details of fracture fixation.

RESULTS

Most dogs in this study (mean age: 2.9 years, mean weight: 9.9 kg) had fractures of three or four bones, and fractures were closed in all but one dog. All fractures involved the metacarpal/metatarsal body, and all but five were transverse. The size of Kirschner wires used for dowel pinning ranged from 0.8 to 2.0 mm, and the length in relation to bone length ranged from 39 to 91%. Axial alignment of internal fixation was and remained anatomically correct and the dowel pins remained in place in all but one dog. This dog had open metatarsal fractures and dowel pinning was contraindicated. Additionally, the Kirschner wires perforated the cortex of the proximal segments, which resulted in implant migration, malunion and residual lameness. The other dogs achieved complete functional union even though seven of 13 dogs developed radiographic signs of synostosis.

CLINICAL SIGNIFICANCE

Although the number of dogs in this study was small, dowel pinning was shown to be technically straightforward, inexpensive and effective for surgical repair of canine metacarpal and metatarsal bone fractures. Further studies should focus on the need for and duration of additional external coaptation.

Surgical management of multiple metatarsal fractures in a chinchilla (Chinchilla lanigera)

CASE DESCRIPTION A 3-month-old sexually intact female chinchilla (Chinchilla lanigera) was examined for sudden onset of non-weight-bearing lameness of the right hind limb. CLINICAL FINDINGS On physical examination, the right pes was swollen. An open wound on the medial aspect of the metatarsal region exposed the second metatarsal bone, and the pes was displaced laterally. Radiographs of the right pes revealed oblique displaced fractures of the 4 metatarsal bones. TREATMENT AND OUTCOME Surgical treatment was elected, and enrofloxacin was administered prior to surgery. The protruding fragment of the second metatarsal bone was excised, and the third and fourth metatarsal bones were repaired with intramedullary pins and external skeletal fixation. The chinchilla was bearing weight on the affected limb 9 days after surgery with only mild lameness. The implants were removed 35 days after surgery when radiographs showed bony union of the third and fourth metatarsal bones and continued reduction of the fractures of the second and fifth metatarsal bones. Fifty-six days after surgery, the chinchilla was bearing full weight on the limb, and radiographs showed bony union of the third, fourth, and fifth metatarsal bones. CLINICAL RELEVANCE Findings suggested that intramedullary pinning combined with an epoxy resin external fixator may be an effective technique for metatarsal fracture repair in chinchillas. This method allowed physiologic positioning of the limb and functional hind limb use during fracture healing. Prospective studies of fracture healing in exotic small mammals are indicated.

Minimally invasive repair of meta-bones

Metacarpal and metatarsal fractures are common injuries in small animals and, in most of the cases, can be treated by minimally invasive techniques. Bone plates applied through epi-periosteal tunnels can stabilize meta-bones. Meta-bones III and IV are stabilized by dorsally applied plates. Meta-bones II and V are stabilized using plates applied medially and laterally. The scarcity of soft tissue coverage and the simple anatomy of meta-bones make these fractures amenable to fixation by using minimally invasive techniques. This practice should reduce morbidity and enhance healing time.