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.

Arthroscopic-assisted hip toggle stabilization in cats: An ex vivo feasibility study

OBJECTIVE

To describe arthroscopic-assisted hip toggle stabilization (AA-HTS) in cats, evaluate its feasibility and associated rate of iatrogenic injury, and assess deviations from planned surgical technique.

STUDY DESIGN

Ex vivo study.

ANIMALS

Skeletally mature cat cadavers (n = 7).

METHODS

Preoperative pelvic computed tomography (CT) was performed for surgical planning and to identify the ideal femoral bone tunnel projection. Ultrasound-guided transection of ligament of head of femur was performed. Following exploratory arthroscopy, AA-HTS was performed using a commercially available aiming device. Surgical time, intraoperative complications, and feasibility of technique were recorded. Iatrogenic injury and technique deviations were assessed by postoperative CT and gross dissection.

RESULTS

Diagnostic arthroscopy and AA-HTS were successfully performed in all 14 joints. Median (range) surgical time was 46.5 (29-144) min, including 7 (3-12) min for diagnostic arthroscopy and 40 (26-134) min for AA-HTS. Intraoperative complications occurred in 5 hips, related to bone tunnel creation (4) and toggle dislodgment (1). Toggle passage through the femoral tunnel was the most challenging component of technique, recorded as mildly difficult in 6 joints. No damage to periarticular/intrapelvic structures was identified. Minor articular cartilage damage (<10% total cartilage area) was identified in 10 joints. Thirteen deviations (8 major, 5 minor) in surgical technique from preoperative planning were identified in 7 joints.

CONCLUSION

In feline cadavers AA-HTS was feasible but was associated with a high rate of minor cartilage injury, intraoperative complications, and technique deviations.

CLINICAL SIGNIFICANCE

Hip toggle stabilization using an arthroscopic-assisted approach may be an effective technique for management of coxofemoral luxation in cats.

Outcome and Complications following Stabilization of Coxofemoral Luxations in Cats Using a Modified Hip Toggle Stabilization-A Retrospective Multicentre Study

OBJECTIVES

 The main aim of this study was to report the surgical technique, the complications and the clinical outcomes of the mini-Tight Rope system (mini-TR) for a modified hip toggle stabilization of coxofemoral luxation in cats.

STUDY DESIGN

 A multicentre retrospective study.

ANIMALS

 Thirty-two client-owned cats.

METHODS

 Medical records (2009-2017) of cats, which underwent stabilization of a coxofemoral luxation with the mini-TR and had at least a 3-month follow-up, were reviewed. The femoral tunnel diameter, the use of one or two FiberWire loops, perioperative complications and clinical outcomes were recorded. Follow-up information was obtained through clinical and radiographic examinations and an owner questionnaire.

RESULTS

 Thirty-two cats met the inclusion criteria. Concurrent injuries were present in 16 cats. A single or double loop mini-TR was used in 21 and 12 cats respectively. One double loop (1/12 cats) and four single loop (4/16 cats) sutures failed. Moderate-to-severe coxofemoral osteoarthritis developed in 14/27 cats. Owner questionnaires revealed excellent clinical outcomes.

CLINICAL SIGNIFICANCE

 Mini-TR with a double-stranded implant is recommended to decrease the risk of suture failure. Osteoarthritis is common after open reduction of hip luxations.

Validation of a biomechanical testing protocol of craniodorsal hip luxation in feline cadavers and comparison of two ultra-high molecular weight polyethylene materials used for extra-articular hip stabilisation

OBJECTIVES

The aim of our study was to describe a biomechanical testing protocol to reproduce ex vivo craniodorsal hip luxation specific to the feline model, and evaluate the biomechanical properties of an intact hip joint compared with the fixation strength of two different techniques of extra-articular hip stabilisation.

METHODS

Eighteen hip joints (femur and hemipelvis) were harvested from nine mature feline cadavers. CT was performed for each hip joint so that a biomechanical base specific to each joint morphotype could be created using computer-aided design. The biomechanical bases were then produced using a three-dimensional printer to secure the hip joints during testing. A total of 34 biomechanical compression tests were performed. Eighteen compression tests were performed in the control group, of which two fractured. The remaining 16 hip joints were then randomly assigned either to group A (hip joints stabilised with an extra-articular ultra-high molecular weight polyethylene (UHMWPE) implant secured by an interference screw [n = 8]) or to group B (hip joints stabilised with a UHMWPE iliofemoral suture [n = 8]).

RESULTS

Mean ± SD yield, failure load and linear stiffness in the control group were 616 ± 168 N, 666 ± 158 N and 231 ± 50 N/mm, respectively. The relative fixation strength (% of intact joint) before hip luxation in groups A and B was 43.8% and 34.7%, respectively. No statistical difference was found between groups A and B for yield and failure load. However, the reoccurrence of craniodorsal hip luxation was higher in group B than in group A, in 5/8 and 0/8 tests, respectively. Moreover, in group A, the extra-articular UHMWPE implant induced caudodorsal hip luxation, reported as failure mode in 7/8 cases.

CONCLUSIONS AND RELEVANCE

This modified biomechanical protocol for testing craniodorsal hip luxation in a feline model was validated as repeatable and with acceptable variance. The extra-articular UHMWPE implant stabilisation technique proved to be more efficient in avoiding reoccurrence of craniodorsal hip luxation than UHMWPE iliofemoral suture.

Traumatic Coxofemoral Luxation in Cats Treated with Hip-Toggle Stabilization Using the Mini Tightrope® Fixation System

The aim of this retrospective study was to evaluate the clinical and radiographic outcomes of 21 cats that underwent coxofemoral toggle stabilization using the Mini TightRope® Fixation System (mTR®). Data were compiled from client-owned cats with traumatic hip luxation. Each cat underwent the same protocol including orthopedic assessment, preoperative radiographic evaluation, surgical procedure, postoperative management and clinical re-examination at 14 days, 8 weeks and 12 months following surgery. Age, body weight, implants and osteoarthritis progression were recorded. A lameness score 0-4 was assigned to each cat. Pain upon hip extension was not quantified but as pain reaction or no pain reaction. Major complications and osteoarthritic (OA) changes were recorded. Osteoarthritic changes were classified on a 0-4 scale. Twenty-one cats were included in the study. Coxofemoral luxations were stabilized using a mTR®. At 8 weeks, weight bearing was considered normal (grade 0) in all cats and no pain reaction was elicited during hip extension. One year after surgery, orthopedic examination was within the normal limits and according to the owners, all animals exhibited a normal physical activity. No complications were recorded. Evidence of slight OA changes were observed in 5 out of 21 cats. The final outcome was considered excellent in 16/21 patients and good in 5/21 cats. The application of the mTR® system can be considered a suitable surgical treatment in cats affected by traumatic hip luxation.

Arthroscopic-Assisted Toggle Rod Stabilization in Canine Coxofemoral Luxation: A Cadaveric Study

OBJECTIVE

 The aim of this study was to describe an arthroscopic-assisted technique for coxofemoral toggle rod placement, and to report on the feasibility, drill tunnel trajectory and accuracy of tunnel aperture location using this method.

STUDY DESIGN

 Cadaveric pilot study.

SAMPLE POPULATION

 Eight coxofemoral joints.

METHODS

 Craniodorsal coxofemoral joint luxations were artificially created. A simulated open hip reduction and stabilization with a toggle rod were performed through a limited arthrotomy under arthroscopic guidance. Computed tomography scans were performed to evaluate drill hole trajectory across the femoral neck, and joints were disarticulated and photographed. Digital imaging software was used to determine the percent overlap of the drill hole apertures relative to the origin and insertion of the round ligament on the acetabulum and fovea.

RESULTS

 The exit point of the tunnel was entirely within the fovea capitis in five of eight femurs, three of eight femoral drill apertures were only partially within the target area. Of the eight acetabular bone tunnels examined, all were centred occupying the acetabular fossa.

CONCLUSIONS

 Coxofemoral toggle rod placement can be performed under arthroscopic guidance through a limited arthrotomy. Comparable femoral tunnel accuracy with the standard open technique should be achieved with the current method prior to its clinical use.

Open hip reduction using a novel transarticular suture stabilisation technique in 24 dogs: a retrospective study of technique, outcome and complications

CASE HISTORY

Medical records of a single private practice (Illinois, USA) were retrospectively reviewed to identify dogs (n=24) that had an open hip reduction with a transarticular suture stabilisation technique after presenting with a traumatic coxofemoral luxation between April 2003 and December 2018.

CLINICAL FINDINGS

Dogs that met the inclusion criteria were of various breeds with a median body weight of 18.1 (min 4.2, max 54.5) kg and mean age at presentation of 6.5 (min 1, max 11) years. The surgical technique, short term outcome and complications were extracted from the medical records. Long-term (>2 years) follow-up data was obtained by a telephone interview with each owner.

TREATMENT AND OUTCOME

All dogs underwent open hip reduction using a novel transarticular suture stabilisation technique. The outcome was reported by owners to be excellent in (18/24) 75% dogs with full return of limb function. Sixty-six percent (16/24) of owners reported that no lameness was observed 2 months after surgery. No minor complications were noted in this study. The hips of 6/24 (25%) dogs reluxated after surgery (defined as a major complication), which required femoral head and neck excision surgery.

CLINICAL RELEVANCE

Open coxofemoral joint reduction using a novel transarticular suture technique is a viable surgical option to consider in dogs that present with a traumatic coxofemoral luxation.

Biomechanical comparison of screw and suture fixation for temporary transarticular tarsocrural immobilization in canine cadavers

OBJECTIVE

To biomechanically evaluate an ultrahigh-molecular-weight polyethylene (UWMWPE) suture for temporary tarsocrural immobilization as a potential alternative to the existing surgical method, which uses a 4.5 AO/ASIF calcaneotibial cortical screw.

STUDY DESIGN

Randomized in vitro biomechanical study.

ANIMALS

Pelvic limbs (n = 20) from 10 euthanized adult dogs (average bodyweight of 29.9 kg ± 1.9 kg).

METHODS

Tarsocrural joints were immobilized either with a 4.5 AO/ASIF screw or a 1 mm diameter UHMWPE suture. Limbs were loaded with 60 N, 120 N, and 180 N, each for 100 cycles. After cyclic loading, immobilizations were loaded until failure. Load at failure and mode of failure were recorded.

RESULTS

Both immobilization methods remained intact during loading with 60 N, 120 N, and 180 N. Mean and standard deviation (± SD) failure loads were higher for the cortical screw (524.9 N ± 148.7 N) than for the UHMWPE suture (387.8 N ± 105.6 N), P = .0084. The stiffness of both systems was equivalent.

CONCLUSION

Both techniques were suitable for transarticular tarsocrural immobilization in large-breed canine cadavers. While load at failure was higher for the screw compared to the suture construct, stiffness of both methods was comparable based on the laboratory settings in this in vitro study.

CLINICAL SIGNIFICANCE

Based on the results of this study, both the cortical screw and the UHMWPE suture stabilized the tibiotarsal joint at clinically relevant loads. However, when exposed to high loads, the cortical screw provides increased tibiotarsal stability. Comparative data need to be collected prior to widespread use of UHMWPE sutures in clinical cases.

Complications and outcomes of cats with coxofemoral luxation treated with hip toggle stabilization using ultrahigh-molecular-weight-polyethylene or nylon (2009-2018): 48 cats

OBJECTIVE

To report overall rate and type of complications and outcomes of cats with coxofemoral luxation managed with hip toggle stabilization (HTS), to compare rate of postoperative complications and outcomes of cats treated with ultrahigh-molecular-weight-polyethylene (UHMWPE) or nylon, and to identify risk factors for reluxation and non-excellent outcomes.

STUDY DESIGN

Multi-institutional retrospective cohort study.

SAMPLE POPULATION

Forty-eight client-owned cats.

METHODS

Medical records of cats that underwent HTS from 2008-2018 using UHMWPE or nylon were reviewed. Univariable and multivariable logistic regression was performed to assess for factors associated with reluxation and non-excellent outcome. Final outcome was obtained from owner questionnaire.

RESULTS

Intraoperative and postoperative complications were recorded in two (4.2%) and 11 (24.4%) cats, respectively. The most common postoperative complication was reluxation (n = 5 [11.1%]). Outcome was classified as excellent in 81.1% and good in 16.2% of cats after a median of 445.5 days (range, 53-3720). No difference in rate of complications or outcomes was identified between UHMWPE and nylon. Performance of additional orthopedic procedures, occurrence of intraoperative complications, and non-performance of capsulorrhaphy were associated with reluxation. Performance of additional non-hip procedures (orthopedic/nonorthopedic) was associated with non-excellent outcome.

CONCLUSION

Hip toggle stabilization was associated with a low rate of intraoperative complications and reluxation and excellent long-term outcomes in most cats. No difference in rate of postoperative complications or outcomes of cats treated using UHMWPE or nylon was identified. Cats that underwent additional orthopedic procedures had greater risk of reluxation.

CLINICAL SIGNIFICANCE

Hip toggle stabilization is an effective technique for management of coxofemoral luxation in cats. Comparable results are expected using UHMWPE or nylon.

Iliofemoral technique modification using an anchor screw as treatment of canine traumatic hip luxation - case report

ABSTRACT Twelve dogs with traumatic hip luxation were selected for surgical intervention with a modified iliofemoral suture technique using an anchor screw to substitute the passage of suture material through a perforated tunnel in the ilium. Six procedures were performed with non-absorbable suture and other six with absorbable suture materials. These cases were evaluated at 15, 30, 60, and 90 days after surgery by performing an ambulation analysis and palpation of the joint. In all cases, there was a return of partial and total limb support in an average of 3 and 19 postoperative, respectively. The fixation strategy of the suture material in the ilium using an anchor screw proved to be efficient with a smaller surgical approach and lesser surgical difficulty, maintaining joint congruence in acute as chronic luxation cases. The use of absorbable and non-absorbable sutures had excellent clinical results, but there was a subjective superiority of the first ones, once 4 dogs of the non-absorbable group presented some discomfort during the postoperative palpation of the joint, 90 days after surgery.

Intra-articular replacement of a ruptured cranial cruciate ligament using the Mini-TightRope in the dog: a preliminary study

BACKGROUND

The TightRope System is a device developed to provide extracapsular stabilization of the cranial cruciate ligament (CCL) rupture in canine stifles. I was then also employed for the extra-articular treatment of shoulder instability and for the intra-articular treatment of hip luxation in dogs and cats.

OBJECTIVES

To evaluate the feasibility of the Mini-TightRope (mTR) System for the intra-articular treatment of CCL rupture in small breed dogs.

METHODS

A cadaveric canine model was used to record the steps of the surgical procedure. Five client owned dogs weighing from 8 to 10 kg and from 2 to 12 years of age were enrolled in the prospective study in which the mTR device was implanted in the stifle joint to replace the ruptured CCL. The dogs were graded using the Bologna Healing Stifle Injury Index (BHSII) and radiographic osteoarthritis (OA) scores.

RESULTS

The outcomes obtained at the time of the surgery (T0) and for the following 12 months (T12) showed an improvement in the functional parameters (BHSII from a median of 74.3 [range, 58.1-82.4] at T0 to 95.6 [range, 94.1-99.3] at T12]). The OA did not change in 3 dogs and increased by only 1 point in 2 dogs.

CONCLUSIONS

In this preliminary study, the mTR was a successful and repeatable intra-articular surgical procedure for all dogs. Additional studies related to the clinical application of the technique in medium-large dogs should be encouraged.

Risk factors for reluxation after toggle rod stabilization for treatment of coxofemoral luxation in 128 dogs

OBJECTIVE

Evaluate the risk factors for reluxation and outcomes for dogs with a toggle rod construct.

STUDY DESIGN

Retrospective case series.

ANIMALS

One hundred twenty-eight client-owned dogs.

METHODS

Medical records from 2007 to 2018 were reviewed for signalment, history, surgery, and outcome for dogs with a coxofemoral luxation repaired with a commercial toggle rod and nylon monofilament suture construct. Univariate and multiple logistics regression analysis were performed to assess risk factors associated with postoperative luxation. Primary veterinarians and owners were contacted for follow-up via telephone or electronic communication.

RESULTS

The overall complication rate was 24.2%, and the reluxation rate was 14.8%. There was a decreased risk of reluxation when the cause was traumatic in origin (odds ratio [OR] 0.10) or when the lameness was severe at presentation (OR 0.42). Fifteen of 58 (25.9%) owners contacted completed a follow-up survey.

CONCLUSION

Dogs with nontraumatic, low impact luxations were at a higher risk for reluxation.

CLINICAL SIGNIFICANCE

Dogs of any body condition with a traumatic coxofemoral luxation are at lowest risk for reluxation.

Coxofemoral Joint Luxation in Dogs Treated with Toggle Rod Stabilization: A Multi-Institutional Retrospective Review with Client Survey

Coxofemoral luxation is the most common type of joint luxation observed clinically in dogs. This retrospective study determines the complications and outcomes of open reduction and internal fixation of coxofemoral luxations using a toggle rod stabilization in 58 dogs. The purpose of the study was to compare the results with previous studies to ascertain commonalities and differences. A majority of the canine luxations were stabilized using a 4.0 or 3.2 mm commercial toggle rod and either one or two strands of OrthoFiber, FiberWire, or monofilament nylon suture. Postoperative complications developed in 25 of the 58 (43%) dogs, with major complications in 9 cases (15.5%). The most common major complication was reluxation, which occurred in 6 dogs (10%). Five of the 6 cases of reluxation received monofilament suture, although there was not a statistically significant relationship between suture type and reluxation. Owner responses to a questionnaire reported good to excellent results for satisfaction with the procedure in 90% of cases. Results of the present study suggest that toggle rod stabilization remains an effective method for the treatment of coxofemoral joint luxation in dogs.

Coxofemoral luxation in pet rabbits: nine cases

Of the pet rabbits presented at one private practice between August 2011 and August 2016 (n=1369), 5·6% presented with a traumatic orthopaedic injury. Of these, 7·8% (n=6) presented with traumatic coxofemoral luxation, the most frequently observed type of luxation. Three cases of non-traumatic coxofemoral luxation in pet rabbits are also discussed. Eight rabbits presented with craniodorsal luxation and one with caudoventral luxation. Five rabbits were initially treated using closed reduction and an Ehmer sling under sedation. Two rabbits responded satisfactorily to closed reduction; their bandages remained in place for 10 and 14 days, and movement was cage-limited for 1 month after bandage placement. The bandage did not prevent re-luxation in three cases. Therefore, two rabbits received iliofemoral nylon sutures, and three rabbits received a femoral neck and head ostectomy. One rabbit was treated directly using open reduction and an iliofemoral nylon suture due to fractures in the same limb. One rabbit was presented in shock, coxofemoral luxation was noticed as an incidental finding and euthanasia was elected by the owner. In conclusion, of the three rabbits treated via femoral neck and head ostectomy one rabbit had an unsatisfactory outcome and two rabbits have non-assessable outcomes. The three rabbits treated with iliofemoral sutures showed satisfactory long-term outcomes and the two rabbits treated with closed reduction and an Ehmer sling showed satisfactory medium and long-term outcomes.

Minimally invasive technique for coxofemoral luxation stabilisation using transarticular toggle system: a cadaveric study

OBJECTIVE

To present a novel, semi-closed, surgical technique for coxofemoral luxation stabilisation using a transarticular toggle rod.

STUDY DESIGN

Cadaveric study.

MATERIALS AND METHODS

Craniodorsal luxation was generated by transecting the ligamentum teres in 12 coxofemoral joints and was then reduced using a closed technique. Anteversion and inclination angles were measured using fluoroscopic projections. An arthroscope was inserted through a bone tunnel drilled from the third trochanter through the femoral neck. Following retraction of the arthroscope, a hole was drilled through the acetabular fossa via the femoral bone tunnel. A standard Arthrex® TightRope toggle button was pushed through the femoral bone tunnel into the acetabular fossa hole and tied over the oval metallic button above the third trochanter site. The exit point of the drill hole over the femoral head and that in the acetabular fossa were evaluated by surgical exposure of the coxofemoral articular surfaces.

RESULTS

The TightRope entrance point into the acetabular fossa was accurate in all joints, with a mean distance from the acetabular fossa centre of 0·06 ±0·1 mm. The measured distance of the TightRope exit point from the femoral head to the fovea capitis was 2·04 ±1·7 mm. Femoral head cartilage damage was detected in nine of 12 joints.

CONCLUSION AND CLINICAL RELEVANCE

Closed reduction and stabilisation of coxofemoral luxations can be achieved using this minimally invasive technique. Refinements to the technique may be needed for its application in clinical cases due to relative high incidence of femoral head cartilage damage.