Minimally invasive tarsal arthrodesis in 15 dogs

OBJECTIVE

The aim of the present study was to report the outcomes and complications of minimally invasive tarsal arthrodesis (MITA) in dogs.

STUDY DESIGN

Bi-institutional retrospective study.

SAMPLE POPULATION

A total of 15 client-owned dogs.

METHODS

Medical records of dogs undergoing MITA were reviewed to determine outcome and complications. Radiographs were recommended every 4 weeks until clinical union and reviewed to evaluate tibiotarsometatarsal alignment, implant position, subsequent osseous union of the debrided articulations. Time to clinical union and complications were recorded. Clinical union was defined as functional weightbearing limb use with at least 50% of osseous union. Final limb function was defined as full, acceptable, or unacceptable.

RESULTS

Partial tarsal arthrodesis was performed in 10 cases and pantarsal arthrodesis in five cases. Postoperative swelling was minimal. Most complications, 26% major and 40% minor, were implant-related, and explant was required in three dogs. No catastrophic complications occurred. Mean (±sd) radiographic follow-up was 11.4 (±13.1) months Mean (±sd) time to radiographic osseous union was 1.8 (±0.5) months. Mean (±sd) time to clinical union was 3.7 (±0.8) months. Physiological alignment was restored in 12/15 dogs. Complete radiographic union occurred in 46% while in the remaining 54% obtained partial radiographic union, but clinical instability was not observed. Limb function was considered full in six and acceptable in eight dogs. Function was unacceptable in one dog, but the cause was not related to MITA.

CONCLUSION

MITA resulted in restoration of alignment, which was accomplished using MITA techniques. Furthermore, MITA appeared to result in faster healing times and reduced soft tissue complications compared to conventional open approach arthrodesis.

CLINICAL SIGNIFICANCE

MITA may be considered as an option to obtain functional arthrodesis in dogs.

Biomechanical evaluation of a fixation technique with a modified hemicerclage for tibial tuberosity transposition: an ex vivo cadaveric study

Objectives

(1) To determine stiffness, load at failure, and mode of failure of a novel fixation method with a tension modified-hemicerclage (MH) for tibial tuberosity transposition, and (2) to compare the biomechanical properties of this novel fixation technique to 2 pins (2Pins) and 2 pins and tension band wire fixation (2Pins + TBW).

Study design

Thirty cadaveric stifles from dogs between 5.2 and 13.1 kg were assigned to 3 treatment groups: Group 1: fixation technique with MH; Group 2: 2Pins; Group 3: 2Pins + TBW. Biomechanical testing was performed with the tibia positioned at an angle of 135° relative to vertical position. Tensile force was applied to the patellar ligament until catastrophic failure was observed. The mode of failure, the load at failure, and the stiffness were compared among treatment groups.

Results

The mean stiffness of the novel fixation (38.1 N/mm ± 7.1) and the 2Pins + TBW (40.2 N/mm ± 9.3) were greater than the 2Pins (26.7 N/mm ± 6.7). There was no significant difference between the novel fixation technique and 2Pins + TBW in stiffness and maximum load to failure. The 2Pins (284.3 N ± 70.5) failed at a significantly lower load than the tension modified-hemicerclage (555.7 N ± 225.9 N) and 2Pins + TBW (715.3 N ± 339.8 N).

Conclusion

A fixation technique using a modified hemicerclage had the same strength and stiffness as the 2Pins + TBW and was stronger and stiffer than the 2 Pins technique in a cadaveric model.

Outcomes and complications of a modified tibial tuberosity transposition technique in the treatment of medial patellar luxation in dogs

OBJECTIVE

To report a modification of the tibial tuberosity transposition (m-TTT) technique used to treat medial patellar luxation (MPL) in dogs, and report its complications.

STUDY DESIGN

Retrospective case series.

SAMPLE POPULATION

Dogs (n = 235) undergoing MPL correction, using m-TTT (n = 300 stifles).

METHODS

Medical records and client surveys were reviewed to determine complications associated with this technique and they were compared with previously reported complications using similar techniques.

RESULTS

Short-term minor complications included low-grade reluxation (11 stifles, 3.6%), incisional seroma (nine stifles, 3%), pin-associated swelling (seven stifles, 2.3%), patellar desmitis (six stifles, 2%), superficial incisional infection (four stifles, 1.3%), pin migration (three stifles, 1%), tibial tuberosity (TT) fracture (two stifles, 0.6%), tibial tuberosity displacement and patella alta (one stifle, 0.3%), pin-associated discomfort (one stifle, 0.3%), trochlear block fracture (one stifle, 0.3%). Short-term major complications included pin migration (three stifles, 1%), incisional infection (two stifles, 0.6%), tibial tuberosity fracture (two stifles, 0.6%), and high grade reluxation (two stifles, 0.6%). Long-term follow-up examination data were available for 109/300 (36.3%) stifles. One minor complication and four major complications were documented. All long-term complications were due to pin migration. The overall major complication rate was 4.3% (13/300 stifles), with a minor complication rate of 15% (46/300 stifles). The owner survey indicated a 100% satisfaction rate.

CONCLUSION

The m-TTT technique yielded acceptable complication rates, with high owner satisfaction.

CLINICAL SIGNIFICANCE

The m-TTT should be considered as an alternative technique for treating dogs with MPL requiring a tibial tuberosity transposition.

Three-dimensional volume rendering planning, surgical treatment, and clinical outcomes for femoral and tibial detorsional osteotomies in dogs

OBJECTIVES

To describe a computed tomographic (CT) methodology for planning the correction of femoral and tibial torsion and report the clinical outcomes after femoral (FDO) and tibial (TDO) detorsional osteotomy in dogs affected by torsion malalignment and patellar luxation (PL).

STUDY DESIGN

Multicenter retrospective study.

ANIMALS

Eighteen client-owned dogs.

METHODS

Dogs underwent CT to measure femoral (FTA) and tibial torsion angle (TTA). Abnormal femoral external torsion was defined when FTA <20°, abnormal femoral internal torsion if FTA >35°; abnormal tibial external torsion was defined when TTA < -10°, and abnormal tibial internal torsion when TTA >2°. The cortical arch length (CAL) was measured with CT and used intraoperatively to determine the magnitude of correction. The medical records and radiographs were reviewed and used to report clinical and radiographic outcomes. Radiographs were reviewed to evaluate postoperative limb alignment, patellar position, and bone healing.

RESULTS

Twenty-two detorsional osteotomies were performed. Mean preoperative FTA was 14° for medial-PL and 45.2° for lateral-PL. Mean preoperative TTA was 11° for medial-PL. Physiological patellar tracking was restored in 22/22 of cases. CAL measurement allowed for correction of abnormal torsion in 19/22 of cases. Seventeen out 18 dogs had full or acceptable functional outcome. The median radiographic follow-up was 3 months. Major complications occurred in 2/22 cases, which suffered an iatrogenic abnormal femoral internal torsion and a persistent hindlimb lameness.

CONCLUSIONS

CAL can be measured with CT and used intraoperatively to guide the correction of abnormal torsion in dogs.

CLINICAL RELEVANCE

Abnormal femoral and tibial torsion are predisposing factors for PL. A higher complication rate is expected when FDO and TDO are performed in the same hindlimb.

Patellar luxation and concomitant cranial cruciate ligament rupture in dogs - A review

A patellar luxation and concomitant cranial cruciate ligament rupture is a common pathology in dogs. Diagnosis is based on clinical evidence of a patellar luxation and stifle joint instability. However, diagnostic imaging is required to assess the number of skeletal deformities and signs of instability. Surgical options include both soft tissue and osseous techniques, although, in most cases, a combination of multiple procedures is necessary to correct the patellar luxation and restore the stifle joint stability. Complication rates are generally low, but can include reluxation and implant-associated complications. This article describes the patellar luxation and cranial cruciate ligament rupture signs in dogs, including the clinical presentation and diagnosis, and discusses current treatment options.

Biomechanical analysis of canine medial patellar luxation with femoral varus deformity using a computer model

Background

Femoral varus deformities complicating the realignment of the quadriceps muscles are frequently associated with medial patellar luxation (MPL) in dogs. Therefore, distal femoral osteotomy (DFO) is recommended in dogs affected with severe MPL and a distal femoral varus deformity. The presence of an anatomic lateral distal femoral angle (aLDFA) of ≥ 102° has been anecdotally recommended as an indication for performing corrective DFO in large-breed dogs. However, the effect of a femoral varus deformity on MPL has not been scientifically evaluated. We aimed to evaluate the influence of a femoral varus deformity on MPL using a finite element method based computer model.

Three-dimensionally reconstructed computed tomographic images of a normal femur from a Beagle dog were deformed using meshing software to create distal varus deformities. A total of thirteen aLDFAs, including 95°, 98° and 100°–110°, were simulated. The patellar positions and reaction force between the patella and trochlear grooves were calculated for all finite element models under constant rectus femoris muscle activation.

Results

The patella was displaced medially from the trochlear groove at an aLDFA of ≥103°. With an aLDFA of 103° to 110°, the reaction force was equal to zero and then decreased to negative values during the simulation, while other models with aLDFAs of 95°, 98°, and 100°-102° had positive reaction force values. The patella began to luxate at 24.90 seconds (sec) with an aLDFA of 103°, 19.80 sec with an aLDFA of 104°, 21.40 sec with an aLDFA of 105°, 20.10 sec with an aLDFA of 106°, 18.60 sec with an aLDFA of 107°, 15.30 sec with an aLDFA of 108°, 16.60 sec with an aLDFA of 109°, and 11.90 sec with an aLDFA of 110°.

Conclusion

Severe distal femoral varus with an aLDFA of ≥103° caused MPL when other anatomical factors were controlled. Thissimplified computer model provides complementary information to anecdotal cutoffs for DFO, hence it should be applied to clinical patients with caution.

A three-dimensional computed tomographic volume rendering methodology to measure the tibial torsion angle in dogs

OBJECTIVE

To describe a three-dimensional (3D) computed tomographic (CT) methodology to measure the tibial torsion angle (TTa) and to evaluate intrarater and interrater agreements and accuracy through comparison with anatomic measurements.

STUDY DESIGN

Ex vivo cadaveric study.

SAMPLE POPULATION

Thirty-six tibiae from 18 dogs.

METHODS

Tibial torsion angle of each tibia was measured by using two CT techniques (axial and 3D volume rendering) by three raters who blindly measured TTa in duplicate. A semitransparent bone filter was used to enhance the visibility of the target anatomical landmarks for the 3D volume rendering CT technique. Tibial torsion angle was also quantitated in tibial specimens. Intrarater and interrater agreements were analyzed by using intraclass coefficients (ICC). Accuracy was evaluated by using adjusted R² coefficients (R²  > 80% was considered acceptable).

RESULTS

The 3D volume rendering CT technique had excellent intrarater and interrater agreements (ICC > 0.94) and an R² value of 97%. The axial CT technique had good to excellent intrarater and interrater agreements (0.8 < ICC < 0.95) and an R² of 86%. No difference was found between axial and 3D CT techniques. A mean internal TT angle of approximately -6° was found with CT and anatomic measurements.

CONCLUSION

The 3D volume rendering and axial CT techniques were precise and accurate for measuring TTa in dogs unaffected by patellar luxation.

CLINICAL RELEVANCE

Combining 3D bone manipulation with application of a semitransparent filter allows simultaneous visualization of anatomic landmarks, which may facilitate the evaluation of complex bone deformations. Internal tibial torsion may be present in nonchondrodystrophic dogs without patella luxation.

Transarticular elastic external skeletal fixator correction of a stifle rotational deformity and patellar luxation in a dog

OBJECTIVE

To report the preoperative evaluation, treatment with transarticular elastic external skeletal fixation (ESF), and outcome of a dog with bilateral medial patellar luxation (MPL) and stifle rotational deformity.

ANIMAL

One nonambulatory, 2.5-month-old, 7.5-kg mixed-breed intact female dog.

STUDY DESIGN

Case report METHODS: Complex pelvic limb deformities were assessed with physical examination and computed tomography (CT) and characterized as bilateral grade 4 MPL and 90° internal rotation of the tibia in relation to the femur. Three-dimensional imaging and bone models were used to quantify the deformity and rehearse surgical correction. Transarticular elastic chains between ESF pins in the femur and tibia were used to gradually correct stifle rotational malalignment on each pelvic limb. Soft tissue releases, imbrication, and a transphyseal staple were used to correct the patellar luxation (PL) and femoral varus. The dog was reevaluated for 1 year postoperatively.

RESULTS

Short- and long-term management included intensive physical rehabilitation to increase pelvic limb strength and function. Surgical treatment resulted in resolution of the PL and neutral stifle alignment. The dog was able to ambulate with persistent decreased range of motion of the stifle.

CONCLUSION

Transarticular elastic chains and femoral physeal stapling improved the function of a dog with severe bone deformities and PL in a growing dog.

Investigation of Variables Associated with Surgical Site Infection following the Management of Canine Cranial Cruciate Ligament Rupture with a Lateral Fabellotibial Suture

OBJECTIVE

 This study investigated variables associated with surgical site infection (SSI) in dogs with cranial cruciate ligament rupture managed with stifle joint examination and lateral fabellotibial suture stabilization.

STUDY DESIGN

 A retrospective study of dogs that had stifle arthroscopy, stifle arthrotomy, or a combination of both, followed by lateral fabellotibial suture stabilization for cranial cruciate ligament rupture. All cases had a minimum follow-up of 90 days. Lameness grades were recorded preoperatively, and at 6-week and final follow-up.

RESULTS

 One hundred fifty procedures in 130 dogs met the inclusion criteria. Overall, SSI rate was 17.3% and removal of the lateral fabellotibial suture was performed in 53% of SSI. Multivariable analysis showed significant association between SSI and bodyweight (p = 0.013), and induction using propofol (p = 0.029). Multilevel ordinal logistic regression analysis showed a greater proportion of dogs had a higher lameness grade at 6-week (p = 0.021) and final follow-up (p = 0.002) assessments in the infected compared with non-infected dogs.

CONCLUSION

 Our study demonstrated a higher SSI incidence than previously reported in dogs undergoing a lateral fabellotibial suture for cranial cruciate ligament rupture. Bodyweight and induction with propofol were identified as significant risk factors for postoperative SSI. Owners could be advised of an increased SSI risk in larger dogs and consideration should be given to selection of induction agent. Dogs that develop an SSI have a worse lameness grade at 6-week and final follow-up.

Radiographic evaluation of patellar tendon length following corrective surgical procedures for medial patellar luxation in dogs

Objective

To quantify changes in the patellar tendon length following surgical correction of medial patellar luxation in dogs and evaluate potential risk factors associated with patellar tendon elongation.

Study design

Retrospective case series (n = 50).

Methods

Dogs that underwent surgery for medial patellar luxation correction and had 2–3 months follow up were included. Digital radiographs were utilized to quantify the patellar tendon length to patellar length ratio at various follow-up points. Odds ratio comparisons between potential risk factors associated with changes in patellar tendon length were performed.

Results

Post-operative patellar tendon lengthening of ≥ 5% was observed in 20% of stifles and post-operative patellar tendon shortening of ≥ 5% was observed in 22% of stifles at the 2–3 month follow up period. The risk factors including age, body weight, trochleoplasty and grade of medial patellar luxation were not significantly associated with risk of patellar tendon elongation. Patellar tendon lengthening was not associated with recurrence of luxation.

Conclusion

Patellar tendon lengthening and shortening can be observed in dogs following common medial patellar luxation corrective procedures in the short term follow up period. Patellar tendon lengthening does not appear to be associated with age, weight, trochleoplasty, grade of luxation, or risk of luxation recurrence.

Evidence of genetic contribution to patellar luxation in Toy Poodle puppies

Patellar luxation (PL) is one of the most common orthopedic disorders in dogs and a genetic factor is considered to play an important role in the development of PL. Genomic analysis has attempted to identify the genetic markers associated with the development of PL but only suggestive markers have been identified. Carefully selecting breeds with higher incidence rates of congenital PL as well as affected dogs with more severe symptoms are required, but such information remains limited to date. This study aimed to assess the genetic contribution to the development of PL in puppies. Using data on PL from 2,048 puppies of the nine common breeds in Japan, the association of PL grades between the limbs, breed, and sex as well as the concordance of PL between littermates were examined. A significant correlation was found between right and left limbs in PL grades in all the puppies (Spearman rank correlation coefficient (r_s)=0.91, P<0.001) and for each breed (r_s=0.81–0.93, P<0.001). In total, 20.3% of the puppies were affected. The inter-breed difference in PL prevalence was 2.1–38.1%, and Toy Poodles showed the highest prevalence rates. Littermates of the affected puppies with PL grade ≥2 had a 16.2-fold higher risk (P<0.001). Thus, these results suggest that PL in puppies is primarily influenced by genetics, especially in Toy Poodles. These data highlight the necessity of using a breeding scheme to decrease the prevalence of PL.