Locking Compression Plates for Pancarpal Arthrodesis in a Thoroughbred Filly

Objective— To report treatment of a comminuted ulnar carpal (UC) bone fracture associated with carpal instability by pancarpal arthrodesis using 2 locking compression plates (LCP).
Study Design— Case report.
Animals— A 2-year-old Thoroughbred filly.
Methods— An UC fracture and luxation of the proximal row of carpal bones was diagnosed radiographically. Pancarpal arthrodesis was performed with 2 LCP positioned dorsolaterally and dorsomedially and centered over the carpus through a single skin incision. The filly was maintained in a full limb cast for 15 days, followed by a tube cast for 14 days, and subsequently a full limb bandage with caudal splint for 21 days.
Results— Two LCP provided appropriate carpal stability resulting in a pasture sound horse 6 months after surgery. The filly was discharged from the hospital 63 days after surgery, walking well with only a slight mechanical lameness.
Conclusion— Use of 2 LCP applied on the dorsomedial and dorsolateral aspect of the carpus can provide carpal stability for pancarpal arthrodesis.
Clinical Relevance— Excellent stability of the carpal joints can be achieved with 2 LCP.     

Severe Comminuted and Spiral Tibial Fracture Managed with a Cross-tied Cast in a Pony

In the horse, diaphyseal tibial fractures are generally comminuted, spiral, and open; they are related to a high-energy accident, which makes them, in general, a catastrophic injury. The major comminution and the open component make of this fracture a real challenge when surgically repaired. For the owner, the costly treatment and the often poor prognosis are two major factors to consider, particularly when dealing with an adult horse. We describe the case of a severe comminuted and spiral, closed fracture of the tibia, with diaphyseal and distal metaphyseal involvement in a pleasure pony. The owner could not afford a surgical intervention, but he refused categorically to euthanize the animal. Considering the closed status of the fracture, a conservative treatment option was offered as a very last option. The tibial fracture was managed successfully with a cross-tied cast.     

Distal Humeral Salter Harris (Type II) Fracture Repair by an Ulnar Osteotomy Approach in a Horse

Objectives: To report repair of a comminuted distal humeral type II Salter–Harris fracture using an ulnar osteotomy approach and locking compression plates (LCP). Study Design: Case report. Animal: A 3‐month‐old Standardbred filly with a type II Salter–Harris fracture of the distal humerus. Methods: Radiographic and computed tomography examinations were performed to assist surgical planning. The distal humeral fracture was approached by an ulnar osteotomy and repaired using a 7‐hole broad LCP and screws inserted in lag fashion. The osteotomy was subsequently repaired using a 7‐hole narrow LCP. Results: The distal humeral fracture was successfully approached and stabilized by an ulnar osteotomy approach. At 6‐month follow‐up, the filly was ambulating comfortably with a normal cosmetic appearance. Conclusions: An ulnar osteotomy approach was readily performed and allowed for repair of a type II Salter–Harris fracture of the distal humerus. Clinical Relevance: The equine distal humerus can be accessed readily using an ulnar osteotomy approach. LCPs allow for repair of complicated fractures that have previously been associated with a grave prognosis.     

Minimally invasive proximal interphalangeal joint arthrodesis using a locking compression plate and tissue engineering in horses: A pilot study

This pilot study assessed the efficacy of 2 minimally invasive techniques for proximal interphalangeal (PIP) joint arthrodesis in horses. The PIP joints of both forelimbs (n = 6) were stabilized with locking compression plates (LCP) using a minimally invasive technique (LCP technique). Subsequently, for 1 randomly selected PIP joint of each horse, surgical drilling (SurD) was performed and tissue engineering (TE) was applied (LCP/SurD/TE technique). Minimally invasive PIP joint arthrodesis with LCP demonstrated low postoperative infection rates. Gross and histological evaluations revealed considerable destruction of the articular cartilage in the LCP/SurD/TE-treated joints. In contrast, almost no destruction of the cartilage was observed in the LCP-treated joints. Our results suggest that the LCP technique alone is not sufficient for PIP joint arthrodesis and that the LCP/SurD/TE technique may be useful for PIP joint arthrodesis in horses.     

Carpal arthrodesis using a minimally invasive approach and locking compression plates: Three cases

Three horses with carpal instability due to comminuted second carpal bone fractures (Cases 1 and 3), fracture of the head of the second metacarpal bone (Case 1) or comminuted fractures of the fourth carpal bone, ulnar and intermediate carpal bones (Case 2) were treated by minimally invasive approach for partial (Cases 1 and 3) or pancarpal (Case 2) joint arthrodesis, using locking compression plates. The joint cartilage was removed by either an arthroscopic approach (middle carpal joint and antebrachiocarpal joint) or a percutaneous drilling technique (carpometacarpal joint). Two or 3 locking compression plates were contoured to the dorsolateral, dorsomedial and dorsoaxial aspects of the carpal joints using a custom‐made tunnelling tool and a minimally invasive tunnelling technique, and the screws were positioned through stab incisions. All cases recovered well, were lame free at the walk, were able to trot and gallop and could be used for leisure and pasture activities (partial carpal arthrodesis) and breeding (pancarpal arthrodesis). Post‐operative x‐rays showed progressive joint fusion after 12 months (Case 1), 5 months (Case 2) and 10 months (Case 3). Case 2 with a pancarpal arthrodesis showed a mechanical lameness at the walk due to the inability to flex the carpus. Carpal flexion after carpometacarpal and middle carpal arthrodesis in Case 1 was calculated to be 42.6° and 44° in Case 3.     

Use of a circular external skeletal fixator for stifle arthrodesis in a dog

Arthrodesis of the right stifle was performed in a 21 kg German shepherd dog that had sustained a comminuted fracture of the lateral femoral condyle as a result of a gunshot wound. The arthrodesis was stabilised with a circular external skeletal fixator. A simplified technique to facilitate creation of the osteotomies of the femur and tibia, and positioning of the stifle at the desired angle, is described. Compression of the subchondral bone surfaces of the distal femur and proximal tibia was achieved using tensioned coiled transarticular Kirschner wires. Arthrodesis of the stifle was confirmed radiographically 21 weeks following surgery, and the fixator was removed. After union of the arthrodesis and removal of the fixator, the dog was fully weightbearing when standing or walking, and intermittently weightbearing or non-weightbearing at faster gaits.     

Computed tomographic documentation of a comminuted fourth carpal bone fracture associated with carpal instability treated by partial carpal arthrodesis in an Arabian filly

OBJECTIVE: To report treatment of a unilateral comminuted fourth carpal bone (C4) fracture associated with carpal instability by partial carpal arthrodesis (PCA) of the middle carpal joint (MCJ) and carpometacarpal joint (CMCJ). STUDY DESIGN: Case Report. ANIMALS: An 8-month-old Arabian filly. METHODS: A C4 slab fracture was diagnosed radiographically; however, fracture comminution was conclusively diagnosed after computed tomographic (CT) imaging. PCA of the MCJ and CMCJ was performed with 2 narrow dynamic compression plates. RESULTS: PCA provided appropriate carpal stability and correct limb alignment immediately after surgery. Complete bony fusion with substantial carpal flexion and no lameness at walk or light trot was observed 8 months after surgery. CONCLUSIONS: Carpal CT was successfully used to define fracture configuration after standard radiographic examination failed to delineate comminution. PCA was selected because of joint instability and lateral carpal collapse of MCJ and CMCJ and can be successfully used to treat comminuted C4 slab fractures associated with carpal instability. Moderate MCJ osteoarthritis without radiocarpal joint involvement allows pain-free, substantial carpal flexion and thus, return to low-level pleasure riding may be possible. CLINICAL RELEVANCE: CT imaging may more adequately characterize traumatic carpal bone injury, particularly, when carpal bone fracture configuration cannot be determined on standard radiographs. Early PCA of the MCJ and CMCJ is an useful alternative to treat comminuted C4 slab fractures that cannot be reconstructed.     

Tarsocrural joint luxation in a horse.

A 14-year-old Quarter Horse x Thoroughbred gelding was admitted to the teaching hospital because of inability to bear weight on its right hind limb, associated with a severe deviation of the tarsus. The provisional diagnosis was tarsal joint luxation or fracture. Radiography revealed complete luxation of the tarsocrural joint. The luxation was reduced, using minimal force. The horse was confined to a box stall and was maintained in a full-length hind-limb cast for 33 days. Box stall confinement was continued for 3 months after removal of the cast. On reexamination 18 months after the injury, the horse had only mild lameness (grade 1 of 5), but had marked reduction in the range of motion of the tarsus. Radiography revealed extensive changes indicative of severe degenerative joint disease. The horse was still used occasionally as a light pleasure riding horse and maintained itself on pasture well.     

Surgical reconstruction of a severely comminuted mandibular fracture in a horse

A Palomino gelding presented for evaluation of a mandibular fracture and physical examination revealed swelling and excoriation of the skin over the ventral mandible. Upon further examination, malalignment of the incisors was appreciated in addition to instability and crepitance of both the rostral aspect and vertical ramus of the mandible. Radiographic examination revealed a comminuted fracture within the interdental space and fractures of both vertical ramii of the mandible. Under general anaesthesia via tracheotomy intubation, the fractures of the vertical ramii were reduced and compression plating techniques used along the caudal‐lateral border of both ramii for stabilisation. Intraoral tension band wires were used for repair of the interdental space fracture. A type II external skeletal fixator using Steinmann pins and polymethyl methacrylate connecting bars was applied to increase stability. The horse was maintained on broad spectrum antibiotics and phenylbutazone and discharged following 6 days of hospitalisation. Radiographs were taken 10 weeks after surgery and revealed evidence of adequate healing. On follow‐up 20 months later, the horse was reported to have no difficulties eating and was maintaining its bodyweight. This case is unique due to the severity of the mandibular fracture. The authors are unaware of any previous reports of such a severely comminuted mandibular fracture and its successful reconstruction employing multiple surgical techniques.     

Clinical evaluation of the locking compression plate for fetlock arthrodesis in six thoroughbred racehorses

Objective— To report use of a locking compression plate (LCP) for fetlock arthrodesis in Thoroughbred racehorses after catastrophic disruption of the suspensory apparatus.
Study Design— Retrospective case study.
Animals— Racing Thoroughbreds (n=6) with a catastrophic breakdown injury of the suspensory apparatus.
Methods— Medical records (2004–2006) of horses that had fetlock arthrodesis using an LCP were reviewed. Preoperative recorded variables were: age, gender, affected limb, injury type and occurrence, limb support used and time to surgery. Recorded surgical variables were: implants used and cost, surgery time, and anesthetic recovery method. Postoperative recorded variables included: treatment, physical status, complications, and outcome.
Results— Of 6 Thoroughbred racehorses that had LCP arthrodesis, 4 were sound for breeding purposes the next year and 2 horses were euthanatized (1 at 16 days, 1 at 68 days) because of proximal interphalangeal joint (PIJ) luxation. No surgical complications were associated with implant application. Postoperative complications were similar to those reported for other arthrodesis techniques.
Conclusions— LCP is a viable option for fetlock arthrodesis in Thoroughbred racehorses after catastrophic suspensory apparatus disruption.
Clinical Relevance— Adequate fetlock stability can be achieved with an LCP, and although the repair is likely more stable it is ∼3 times more expensive than using a limited contact dynamic compression plate (LC-DCP) with cortical screws.     

Successful treatment of a severely contaminated open metatarsophalangeal joint luxation by arthrodesis

A horse with an open medial luxation of the left metatarsophalangeal joint with extensive cartilage and soft tissue damage and severe contamination of the wound was treated with a two-stage approach. In the first stage, the lesion was cleaned, the luxation was reduced, the wound was sutured and the limb was kept in a cast for a total time of 56 days. In the second stage, an arthrodesis of the affected joint was carried out, using a 13-hole broad 4.5 LCP plate. The limb was then kept in a cast for an additional total time of 56 days. At 70 days after the arthrodesis, the horse was brought in for a final check-up, and only a mechanical lameness remained at that time. No significant complications occurred. Previous case reports on the treatment of metatarso-/metacarpophalangeal luxations include neither cases as severe as the one presented here nor treatment by fetlock arthrodesis. This case illustrates that horses with a complicated, open luxation of the fetlock can be salvaged for breeding purposes.     

Fracture of the humerus after cancellous hone graft harvesting in a dog

A five-year-old male Shetland sheepdog underwent calcaneoquartal arthrodesis for instability of the proximal intertarsal joint. A cancellous bone graft was harvested from the proximal humerus and packed around the arthrodesis site. Twenty-four hours postoperatively the dog developed a non-weightbearing forelimb lameness. Clinical and radiographic examination revealed a fracture of the humerus through the hole used to obtain the graft. Surgical repair of the fracture led to an uneventful recovery.     

Computed tomography assisted diagnosis and treatment of a comminuted fracture of the plantar aspect of the medial trochlear ridge and the proximal tubercle of the talus in a foal

Isolated fractures of the proximal tubercle of the talus and the medial trochlear ridge of the talus have been reported in the equine literature. A comminuted, intra-articular fracture of the plantar medial trochlear ridge and proximal tubercle of the talus has not been previously reported. The current case report describes this unique comminuted fracture in a 6-week-old Thoroughbred foal with acute onset lameness. The diagnosis was achieved by a combination of radiography, ultrasonography and computed tomography (CT) followed by CT arthrography. Surgical removal of the fracture fragments was recommended; the intra-articular fracture fragments were removed under arthroscopic visualisation of the plantar pouch of the tarsocrural joint; due to ligamentous attachments and partial extra-articular nature, the fracture fragment of the proximal tubercle of the talus was removed via an arthrotomy extension of the medial arthroscopy portal. On follow-up examination 12 months post-operatively, the yearling showed no clinical evidence of lameness or radiographic evidence of secondary degenerative joint disease.     

In vitro mechanical evaluation on the use of an intramedullary pin-plate combination for pantarsal arthrodesis in dogs

OBJECTIVE: To compare the biomechanical properties of pantarsal arthrodesis achieved with a dorsal bone plate-alone (BPA) or pin-plate combination (PPC). SAMPLE POPULATION: 8 pairs of cadaver canine tarsi. PROCEDURE: Within a pair, 1 tarsus was arthrodesed by use of a 13-hole 3.5-mm broad dynamic compression bone plate applied to the dorsal aspect of the tarsus; the paired tarsus received an identical plate similarly applied, with the addition of an intramedullary pin filling approximately 40% of the tibial medullary canal, spanning the tibiotarsal joint. Plates were instrumented with strain gauges proximal and distal to the solid portion of the plate. Specimens were mounted on a servo-hydraulic testing machine and loaded at 20%, 40%, and 80% of body weight for 10 cycles at 1 Hz. Construct compliance, angular deformation, and plate strain were determined during the 10th cycle. RESULTS: PPC specimens were less compliant than BPA specimens at all loads and had significantly less angular deformation than BPA specimens at loads of 40% and 80% of body weight. Tibiotarsal gauge microstrain was significantly less in PPC specimens, compared with BPA specimens, regardless of loads. Maximal strains were 33.5% to 40.5% less in PPC than BPA specimens. CONCLUSIONS AND CLINICAL RELEVANCE: For pantarsal arthrodesis in dogs, our results indicate that the PPC construct is biomechanically superior to the BPA construct. By improving construct stability, addition of an intramedullary pin to the traditional BPA technique may lessen implant-related complications and improve plate fatigue life. A subsequent decrease in postoperative morbidity may occur with little addition of time or complexity to the surgical procedure.     

Assessment of stiffness and strength of 4 different implants available for equine fracture treatment: a study on a 20 degrees oblique long-bone fracture model using a bone substitute

OBJECTIVE: To compare the mechanical properties of 4 stabilization methods for equine long-bone fractures: dynamic compression plate (DCP), limited contact-DCPlate (LC-DCP), locking compression plate (LCP), and the clamp-rod internal fixator (CRIF--formerly VetFix). STUDY DESIGN: In vitro mechanical study. SAMPLE POPULATION: Bone substitute material (24 tubes) was cut at 20 degrees to the long axis of the tube to simulate an oblique mid-shaft fracture. METHODS: Tubes were divided into 4 groups (n=6) and double plated in an orthogonal configuration, with 1 screw of 1 implant being inserted in lag fashion through the "fracture". Thus, the groups were: (1) 2 DCP implants (4.5, broad, 10 holes); (2) 2 LC-DCP implants (5.5, broad, 10 holes); (3) 2 LCP implants (4.5/5.0, broad, 10 holes) and 4 head locking screws/plate; and (4) 2 CRIF (4.5/5.0) and 10 clamps in alternating position left and right of the rod. All constructs were tested in 4-point bending with a quasi-static load until failure. The implant with the interfragmentary screw was always positioned on the tension side of the construct. Force, displacement, and angular displacement at the "fracture" line were determined. Construct stiffness under low and high loads, yield strength, ultimate strength, and maximum angular displacement were determined. RESULTS: None of the implants failed; the strength of the bone substitute was the limiting factor. At low loads, no differences in stiffness were found among groups, but LCP constructs were stiffer than other constructs under high loads (P=.004). Ultimate strength was lowest in the LCP group (P=.01), whereas yield strength was highest for LCP constructs (409 N m, P=.004). CRIF had the lowest yield strength (117 N m, P=.004); no differences in yield strength (250 N m) were found between DCP and LC-DCP constructs. Differences were found for maximum angular displacement at the "fracture" line, between groups: LPC相似文献   

Fixation of a complete scapular neck fracture in a foal using two 3.5 mm locking compression plates

This report describes the successful surgical repair of a transverse, displaced scapula fracture in a foal. A 3.5 mm locking compression plate (LCP) was used on either side of the spine of the scapula. The suprascapular nerve was apparent upon dissection as it passed directly over the fracture line and care was taken to leave it intact, although the fracture line itself caused some irritation. The foal recovered without long‐term nerve damage and is sound at 1.5 years post surgery.     

Clinical Use of Recombinant Human Bone Morphogenic Protein-2 in a Whooping Crane (Grus americana)

Objective— To report use of recombinant human bone morphogenetic protein-2 (rhBMP-2) as adjunctive therapy for treatment of a comminuted, open, proximal humeral fracture in an avian species.
Study Design— Clinical report.
Animals— A 3.5-month-old male whooping crane ( Grus americana ).
Methods— An open, severely comminuted humeral facture was stabilized with an intramuscular (IM) pin/type IA external skeletal fixator with tie-in configuration. rhBMP-2 was applied in a calcium phosphate matrix (CPM) paste directly to the fracture site as a bone graft substitute. Radiographic evidence of bone healing was monitored for 14 weeks.
Results— Substantial bony callus was evident at 4 weeks and at 8 weeks there was bridging callus with obvious bony remodeling. The fixation was destabilized at 9 weeks by IM pin removal, bone healing progressed and the fixator was removed at 11 weeks. By 14 weeks both cortices had been re-established with continued callus remodeling evident.
Conclusion— rhBMP-2, applied in a CPM paste, was used as a bone graft substitute in the treatment of a comminuted, open humeral fracture in a whooping crane.
Clinical Relevance— Use of rhBMP-2/CPM should be considered in treatment of avian fractures.     

Ulnar interlocking intramedullary nail stabilization of a proximal radio-ulnar fracture in a dog

Objective: To report use of an ulnar interlocking intramedullary nail for repair of an open highly comminuted fracture of the proximal third of the antebrachium in a dog, caused by gunshot. Study Design: Case report. Animals: 1.5‐year old, 60 kg, neutered male Mastiff. Methods: An ulnar interlocking intramedullary nail was used to stabilize an open comminuted proximal antebrachial fracture and a cast applied for 4 weeks. Results: Union by secondary bone healing occurred in 8 weeks. At 16 weeks, there was advanced remodeling of the radial and ulnar bony callus and fracture lines were no longer evident. Limb use was normal with normal pain free range of motion of the right elbow. Conclusion: Ulnar interlocking nail is a viable alternative treatment for highly comminuted fracture of the proximal third of the antebrachium in dogs.     

Treatment of a femoral fracture with a titanium locking compression plate distal femur (LCP‐DF) in a young donkey

A closed complete mid‐diaphyseal spiral fracture of the left femur in a one‐year‐old donkey was treated with a 4.5 mm titanium locking compression plate distal femur (LCP‐DF)¹. This plate was originally manufactured for human orthopaedics, primarily for femoral osteosynthesis. The LCP‐DF¹ has a distal head plate that was advantageous in this case because the distal fragment was smaller. Post operative radiographs showed optimal femoral reconstruction and a callus was present 3 weeks after surgery. The donkey was sound at the walk and trot 2 months after surgery. Radiographs taken 5 months after surgery showed stable implants and complete healing without complications.     

External fixation repair of a displaced comminuted radial fracture in a juvenile camel

A young female camel had a complete comminuted midshaft fracture of the right radius. The fracture was repaired by external coaptation, which involved 2 full-limb fiberglass casts for 15 weeks. A Thomas splint was placed around the second cast for 12 weeks. The fracture healed in nonaligned configuration, and although lameness was substantial after the fracture had healed, the camel's breeding potential had been salvaged. This successful outcome is an indication that a high-limb fracture in a camel bone (in this case a radius) may be managed by external coaptation and repair by callus formation.