Correction of pes varus deformity in a Miniature Dachshund by true spherical osteotomy with a dome saw blade

Clément Sellier 1Fitzpatrick Referrals, Godalming, GU7 2QQ, England.

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Michael M. Dosal 1Fitzpatrick Referrals, Godalming, GU7 2QQ, England.

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James W. Guthrie 1Fitzpatrick Referrals, Godalming, GU7 2QQ, England.

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Noel Fitzpatrick 1Fitzpatrick Referrals, Godalming, GU7 2QQ, England.

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Abstract

CASE DESCRIPTION

A 6-month-old male Miniature Dachshund was referred for examination and correction of a unilateral pes varus deformity.

CLINICAL FINDINGS

Clinical examination and diagnostic imaging revealed varus, procurvatum, and internal torsion of the distal aspect of the left tibia causing intermittent lameness.

TREATMENT AND OUTCOME

True spherical osteotomy performed with a dome-shaped saw allowed correction of the deformity in 3-D, and orthogonal internal plate fixation provided stabilization. No intraoperative or immediate postoperative complications developed. Outcome as judged by the clinician and the owners was satisfactory 2 weeks after surgery and excellent at each subsequent assessment. The patient remained free of clinical signs at the last follow-up 30 months after surgery.

CLINICAL RELEVANCE

To the authors’ knowledge, this case represented the first time a true spherical osteotomy was used to correct a pes varus deformity in a canine patient.

Abstract

CASE DESCRIPTION

A 6-month-old male Miniature Dachshund was referred for examination and correction of a unilateral pes varus deformity.

CLINICAL FINDINGS

Clinical examination and diagnostic imaging revealed varus, procurvatum, and internal torsion of the distal aspect of the left tibia causing intermittent lameness.

TREATMENT AND OUTCOME

True spherical osteotomy performed with a dome-shaped saw allowed correction of the deformity in 3-D, and orthogonal internal plate fixation provided stabilization. No intraoperative or immediate postoperative complications developed. Outcome as judged by the clinician and the owners was satisfactory 2 weeks after surgery and excellent at each subsequent assessment. The patient remained free of clinical signs at the last follow-up 30 months after surgery.

CLINICAL RELEVANCE

To the authors’ knowledge, this case represented the first time a true spherical osteotomy was used to correct a pes varus deformity in a canine patient.

A 6-month-old 4.2-kg (9.3-lb) sexually intact male Miniature Dachshund was referred for assessment and correction of a deformity of the distal aspect of the left pelvic limb. Lameness of the affected limb was observed after intense exercise. The deformity was clinically characterized by varus of the distal portion of the tibia (ie, pes varus). Results for the rest of the patient's physical and orthopedic examination were unremarkable.

The dog was sedated for diagnostic imaging. Orthogonal (caudocranial and mediolateral) radiographic views of both pelvic limbs were obtained. A CT scan was performed with images obtained in the dorsal, sagittal, and transverse planes, and a 3-D reconstructed image of the affected limb was created by use of simulation softwarea (Figure 1). Measurements of the proximal and distal joint orientation lines, mechanical axis of the tibia, and CORA for the affected limb were performed on digital radiographs as previously described.1,2 The findings confirmed that varus, procurvatum, and internal torsion of the distal portion of the left tibia were present (Figures 2 and 3).

Figure 1—
Figure 1—

A 3-D reconstructed CT image of the left pelvic limb of a 6-month-old Miniature Dachshund that had lameness after exercise. A varus deformity with internal torsion of the distal aspect of the tibia is evident.

Citation: Journal of the American Veterinary Medical Association 257, 6; 10.2460/javma.257.6.624

To assess the varus deformity, proximal and distal joint orientation lines and the mechanical axis of the tibia were first plotted on the caudocranial radiograph of the unaffected limb, and the mechanical medial proximal tibial angle and the mechanical medial distal tibial angle were measured. These angles were then plotted on the caudocranial radiograph of the affected limb to draw proximal and distal mechanical axis lines of the unaffected bone on the affected bone. The site where the proximal and distal mechanical axis lines intersected was the CORA. The acute angle created by these 2 intersected axes corresponded to the degree of deformity that required correction (Figure 2). The procurvatum was similarly assessed by measuring the mechanical cranial proximal tibial angle and the mechanical cranial distal tibial angle on the unaffected limb and then plotting these angles and axes on the affected tibia (Figure 3). These measurements were cross-checked by CT examination with previously reported techniques.3 The degree of tibial torsion was determined from transverse CT images by measurement of the angle created between the caudal transcondylar axis proximally and the cranial surface of the tibia distally.3 The measurements for the unaffected right tibia were as follows: mechanical medial proximal tibial angle, 91.9°; mechanical medial distal tibial angle, 94.4°; mechanical cranial proximal tibial angle, 93.7°; mechanical cranial distal tibial angle, 80.2°; and tibial torsion, 5.8°. Preoperative differences between the right and left tibias at the CORA were 27.3°, 14.0°, and 4.3° in the dorsal, sagittal, and transverse planes, respectively.

Figure 2—
Figure 2—

Preoperative caudocranial radiographs of the unaffected right (A) and affected left (B) tibias of the dog in Figure 1 depicting placement of joint orientation and mechanical axis lines for assessment of the varus deformity. Proximal and distal joint orientation lines (PJOL and DJOL, respectively) and the mechanical axis (MA) of the tibia were first plotted and used to measure the mechanical medial proximal tibial angle (mMPTA) and mechanical medial distal tibial angle (mMDTA) on the radiograph of the unaffected limb. These angles were then plotted according to the same anatomic landmarks on the radiograph of the affected limb, and the proximal and distal tibial axes (PTA and DTA, respectively) were used to identify the CORA and the degree of angular deformity to be corrected. L = Left. R = Right.

Citation: Journal of the American Veterinary Medical Association 257, 6; 10.2460/javma.257.6.624

Figure 3—
Figure 3—

Preoperative mediolateral radiographs of the unaffected right (A) and affected left (B) tibias of the dog in Figure 1. The joint orientation and mechanical axis lines were plotted on the unaffected tibia for determination of the mechanical cranial proximal tibial angle (mCrPTA) and the mechanical cranial distal tibial angle (mCrDTA), which were then plotted on the radiograph of the affected tibia for determination of the CORA and degree of procurvatum to be corrected. See Figure 2 for remainder of key.

Citation: Journal of the American Veterinary Medical Association 257, 6; 10.2460/javma.257.6.624

All treatment options were discussed with the client, and consent was provided to proceed with surgical correction through a novel TSO procedure. The patient was premedicated with methadoneb (0.2 mg/kg [0.09 mg/lb], IV) and medetomidinec (8 μg/kg [3.6 μg/lb], IV), and general anesthesia was induced with propofold (4 mg/kg [1.8 mg/lb], IV) and maintained with isofluranee in oxygen. Preoperative analgesic treatments included epidural administration of morphinef (0.15 mg/kg [0.07 mg/lb]) and bupivacaineg (0.7 mg/kg [0.32 mg/lb]) and IV administration of methadoneb (0.2 mg/kg). An antimicrobial (cefuroxime,h 20 mg/kg [9.1 mg/lb], IV) was administered 30 minutes prior to the first incision and every 90 minutes for the duration of the procedure.

The patient was positioned in dorsal recumbency, and the entire left pelvic limb was aseptically prepared for surgery. One surgical assistant held the paw and femur so that the tibia was kept parallel to the table surface throughout the procedure; this was done to aid stabilization of the limb and provide an accurate reference for the surgeon. The first incision was made through the skin and subcutaneous fascia over the lateral aspect of the limb approximately halfway between the tarsal and stifle joints. A transverse fibular osteotomy was performed with a microsagittal saw bladei after retraction of soft tissue with Hohmann retractors.

A craniomedial approach to the tibia was performed from the middle of the tibial diaphysis down to the cranial aspect of the tarsus. Cranial exposure of the tibiotarsal joint allowed accurate observation of the joint angle and location. This improved implant placement and helped avoid violation of the articular surface. Distal tibial osteotomy was performed with a 12-mm dome osteotomy saw blade.j The size of saw blade was selected on the basis of previously published recommendations.4 Briefly, the blade with the smallest diameter was selected for which the diameter of the blade was still greater than the width of the bone, in both the dorsal and sagittal planes, at the level of the proposed osteotomy. The bone width measured on preoperative radiographs was 10.8 mm in the dorsal plane and 7.4 mm in the sagittal plane, leading to selection of the 12-mm blade.

The starting location on the tibia for the saw blade was chosen on the basis of measurements made on preoperative radiographs. Circles were drawn around the CORA with a 12-mm radius (matching that of the saw blade) to mimic the desired osteotomy location in the dorsal and sagittal planes. On the caudocranial radiograph, the proximal points where the circle bisected the medial and lateral cortices of the tibia were identified. On the mediolateral radiograph, the proximal point where the circle bisected the cranial cortex was identified. For each of these 3 points, the distance to the most craniodistal point of the tibial cochlea was measured. This point on the tibial cochlea was located during surgery, the 3 described distances were measured on the tibia, and the saw blade was positioned on the cranial aspect of the tibial cortex in line with the 3 points. The insertion angle of the saw blade relative to the long axis of the tibia was calculated by use of a previously reported formula.4 A surgical assistant used a goniometer during surgery to aid the surgeon's alignment of the saw blade, and the cut was completed to create proximal and distal segments.

The distal segment was rotated counterclockwise (to correct the varus) with a slight external rotation (to correct the internal torsion) and cranially (to correct the procurvatum). The distal segment was to be rotated relative to the proximal segment in the transverse, dorsal, and sagittal planes at distances determined by use of the following formula:

article image

where a is the angle between the proximal and distal mechanical axes at the CORA in the respective plane and r is the radius of the saw blade. A caliper was used to measure these distances during surgery.

Initial stabilization was achieved with a 1.4-mm Kirschner wire inserted through the lateral aspect of the distal portion of the fibula, through the lateral cortex of the distal tibial fragment, across the osteotomy, and through the medial cortex of the proximal tibial fragment. Rigid fixation across the osteotomy site was accomplished with two 2.0-mm locking compression plates.k A 4-hole plate was placed cranially and secured with four 2-mm cortical screws, and a 6-hole plate was placed medially and secured with five 2.0-mm cortical screws. All screws were nonlocking. Limb alignment was deemed appropriate during surgery, and there was no impingement to stifle joint or tarsal joint range of motion. An allograftl of canine cancellous bone chips (1 cm3 of freeze-dried fine [< 1 mm] pieces) was packed adjacent to the medial side of the osteotomy. The incisions were closed routinely. Radiographic and CT assessments were performed immediately after surgery and revealed satisfactory limb alignment and implant positioning. Intraoperative photographs and immediate postoperative radiographs are provided (Figure 4). Single-energy metal artifact reduction was used to remove artifacts caused by the implants during CT imaging. Postoperative differences between the right and left tibias at the CORA were 2.6°, 6.5°, and 0.6° in the dorsal, sagittal, and transverse planes, respectively.

Figure 4—
Figure 4—

Intraoperative photographs (A and B) and immediate postoperative radiographs (C) of the dog in Figure 1. A—The affected limb was supported by an assistant as shown throughout the surgery. Abnormalities of the tibial region are grossly evident. B—Photograph of the TSO created with the 12-mm dome saw blade. C—Composite radiographic image (caudocranial and mediolateral views [left and right sides of the image, respectively]) showing alignment of the proximal and distal parts of the affected tibia and placement of implants.

Citation: Journal of the American Veterinary Medical Association 257, 6; 10.2460/javma.257.6.624

For analgesia, a transdermal fentanyl patchm (1.5 μg/kg/h [0.68 μg/lb/h]) was applied immediately after surgery and maintained for 3 days afterward. Prior to the fentanyl patch being deemed active in this dog on the basis of pain score assessments5 (12 hours after application), methadoneb (0.2 mg/kg, IV) was administered every 4 hours. Treatment with meloxicamn (0.1 mg/kg [0.045 mg/lb], PO, q 24 h) was initiated the evening following surgery. A soft, padded, compressive bandage was applied for 48 hours; on removal of the bandage, a small volume of serosanguineous discharge from the craniomedial surgical incision was noted; because of concerns about surgical site contamination, treatment with cephalexino (17 mg/kg [7.7 mg/lb], PO, q 12 h) was initiated. The patient was discharged from the hospital 4 days after surgery. Instructions for initial postoperative care given to the owners included routine incision care, continued administration of cephalexin (for a total of 10 days) and meloxicam (for a total of 4 weeks), and confinement of the patient in a crate for 6 weeks. Exercise was restricted to 10-minute walks with the dog on a leash, beginning 4 times daily for 6 weeks and then gradually increasing on-leash activity for another 6 weeks.

An individual certified as a specialist by the Royal College of Veterinary Surgeons performed clinical assessments on the day the dog was discharged from the hospital and 2, 6, 12, and 24 weeks after surgery. At each assessment, subjective lameness grade, stability of the osteotomy, joint range of motion, and signs of pain on examination were assessed and recorded. Lameness was evaluated on a scale of 0 to 5 as previously described6 and graded as moderate (3/5) at the time of discharge (4 days after surgery) and mild (1/5) at the 2-week follow-up, with no lameness (0/5) present at any of the subsequent examinations. Mild discomfort was detected on manipulation of the limb on the day of hospital discharge but was not found at any of the recheck examinations. Tarsal joint range of motion of the left pelvic limb was the same as that of the contralateral limb, and the osteotomy was palpably stable throughout all postoperative assessments. Although meloxicam administration was recommended for 4 weeks, the clients continued to give the medication until the bottle was empty, resulting in administration for 5 weeks. The instructions for strict crate rest and exercise restriction were not followed by the owners; however, no clinically important consequences were observed, and no additional analgesic medication was needed. Radiographic and CT assessments revealed satisfactory alignment and no disruption of the implants 6 weeks after surgery; osseous union had developed by 12 weeks after surgery. Photographs and selected radiographic images obtained during follow-up visits are provided (Figure 5). A telephone interview with the owner 30 months after surgery revealed the patient remained free of lameness or signs of pain in the treated limb.

Figure 5—
Figure 5—

Photographs obtained at a 6-week follow-up examination (A, B, and C) and caudocranial (D) and mediolateral (E) radiographs obtained at a 12-week follow-up examination for the same dog in Figure 1. Symmetry of the pelvic limbs was judged satisfactory. Osseous union had developed at the osteotomy site by week 12. See Figure 2 for key.

Citation: Journal of the American Veterinary Medical Association 257, 6; 10.2460/javma.257.6.624

Discussion

Pes varus is the result of a growth disturbance characterized by asymmetric closure of the distal tibial physis, leading to various degrees of medial tibial cortex shortening and (resultant) varus deformity of the distal tibial segment.7 The prevalence of pes varus among dogs is low, but Dachshunds are over-represented.8 As the affected dog matures, deformity of the tibia becomes progressively worse, resulting in abnormal medial loading of the talocrural joint9; this leads to functional problems when the deformity progresses beyond the dog's ability to compensate.8 In the absence of surgical correction, patients may develop various degrees of ligament tearing, lameness, pain, lateral patellar luxation, and osteoarthritis.7–10

The term pes varus implies a unidirectional varus deformity. Although the varus deformity is the predominant abnormal conformation, the condition can result in a multidirectional growth abnormality. As previously reported for Miniature Dachshunds,11 the mechanical cranial distal tibial angle and mechanical medial distal tibial angle can differ significantly between normal limbs and limbs affected by pes varus. This indicates the presence of a multidirectional deformity. The optimal surgical procedure should aim to correct all directions of deformity simultaneously.

Definitive treatment of pes varus requires surgical correction. Patients with pes varus are typically presented at an age when techniques such as transphyseal stapling or periosteal elevation would be inappropriate because insufficient growth potential remains for self-correction of the condition.12 Transphyseal stapling slows growth on one side of the physis, whereas periosteal elevation aims to enhance growth on one side of the physis. The aim of slowing growth on the convex side of the bone with deformity and hastening growth on the concave side is to correct the deformity and straighten the bone. The previously reported techniques to correct pes varus in canine patients are either closing13 or opening7,9,10,13,14 wedge osteotomies. Proposed disadvantages of closing wedge osteotomies are the difficulty in accurately executing an osteotomy that will correct the deformity in 3 planes and the reduction in bone length after the procedure. An important disadvantage of an opening wedge osteotomy is the limited bone contact that is achieved following realignment of the tibia.10 Minimal load sharing between bone fragments puts increased stress on the implants used for stabilization, which may predispose them to failure.

A TSO is able to overcome the described disadvantages of closing and opening osteotomies. A TSO is a single osteotomy that allows the resultant 2 fragments of bone to be manipulated in frontal, sagittal, and transverse planes relative to each other, therefore allowing simultaneous correction of multidirectional deformities.15–18 After a TSO, the bone fragments can be realigned with a greater surface area of bone contact between the fragments than can be accomplished with an opening osteotomy. This may allow greater load sharing for the bone fragments and less force on the stabilization implants. The change in overall bone length after a TSO is less than that after a closing ostectomy.p Reported benefits of a TSO for correction of antebrachial deformities include maximal contact between bone fragments, expedited healing, and minimal translation.p–r

The TSO for the dog of this report was performed with a dome osteotomy saw blade. The shape of the blade creates a precise spherical osteotomy, resulting in matching spherical dome (concave and convex) surfaces. The use of this saw blade has been described for the correction of canine antebrachial deformitiesq,r; to our knowledge, its use for the correction of canine tibial deformities has not been previously reported, and the principle of the TSO and use of a dome saw blade may be applicable to alignment correction for other long bones in dogs with congenital or developmental deformities.

After limb realignment following TSO, the tibia could have been stabilized by internal or external fixation. Internal fixation with orthogonal plates was selected to allow compression across the osteotomy site with rigid fixation and to reduce the aftercare and potential complications that would be expected with an external skeletal fixator. Nonlocking screws were used so that their trajectory could be adjusted to avoid the osteotomy site, tibiotarsal joint, Kirschner wire, and orthogonal screws. Immediate postoperative CT images revealed that the 2 distal screws in the cranial plate engaged the caudal aspect of the tibial cortex but did not protrude beyond it; therefore, these screws ideally should have been longer. We deemed revision was not required because, in addition to the Kirschner wire, 6 other cortical sites were engaged with screws distal to the osteotomy site (2 screws each through the cranial, medial, and lateral aspects of the cortex). All other screws were confirmed to have bicortical fixation.

Opinions vary on whether a fibular osteotomy should be performed in dogs undergoing tibial osteotomy. Some authors have reported difficulty reducing the osteotomy and applying an external skeletal fixator after fibular osteotomy.10 Other surgeons proposed that preserving the fibula may be beneficial, as it can act as an internal splint during recovery.9 The authors of a small case series reported no complications after iatrogenic fibular fracture and found no apparent impact of this factor on the accuracy of the varus correction, suggesting that an intact fibula may not be clinically important.14 We agree that preservation of the fibula may provide some mechanical advantages in theory but considered that it could interfere with realignment and apposition of the tibia fragments for this patient. Additionally, we deemed that our construct was robust enough to allow a fibular osteotomy. An allograft was used instead of an autograft to reduce creating complications associated with a secondary surgical site and decrease surgical time.

To our knowledge, the use of a TSO to treat pes varus in a dog has not previously been reported. This report describes TSO of the affected tibia with a dome saw blade and stabilization of the bone fragments with orthogonal internal plate fixation as treatment for pes varus in a juvenile Miniature Dachshund. A good outcome was achieved in this patient.

ABBREVIATIONS

CORA

Center of rotation of angulation

TSO

True spherical (dome) osteotomy

Footnotes

a.

Toshiba Aquilion Prime 160 Slice, version 7, Canon Medical Systems Corp, Ōtawara, Japan.

b.

Martindale Pharmaceuticals Ltd, Romford, England.

c

Domitor, Vetoquinol UK Ltd, Towcester, England.

d.

Abbott Laboratories Ltd, Maidenhead, England.

e.

Isoflo, Abbott Laboratories Ltd, Maidenhead, England.

f.

Martindale Pharmaceuticals Ltd, Romford, England.

g.

Marcain, AstraZeneca, Luton, England.

h.

Zinacef, GlaxoSmithKline, Uxbridge, England.

i.

Platinum Series Micro Sagittal Saw, Whittlemore Enterprises, Rancho Cucamonga, Calif.

j.

DomeSaw blade, Matrix Orthopedics Inc, Twin Falls, Idaho.

k.

LCP, DePuy Synthes, West Chester, Pa.

l.

Veterinary Tissue Bank Ltd, Wrexham, Wales.

m.

Duragesic, Janssen-Cilag Ltd, High Wycombe, England.

n.

Metacam, Boehringer Ingelheim, Bracknell, England.

o.

Therios, Ceva Animal Health Ltd, Amersham, England.

p.

Fox DB, Fasanella FJ, Tomlinson JL. Comparison of osteotomy techniques for the correction of antebrachial angular limb deformities in the dog: investigation of a novel dome osteotomy saw blade (abstr), in Proceedings. 37th Annu Conf Vet Orthop Soc 2010;20.

q.

Fitzpatrick N, Nikolaou C, Ochoa J, et al. True spherical dome osteotomy using a novel blade design in a dog with an antebrachial growth deformity: planning and execution of technique (abstr), in Proceedings. 38th Annu Conf Vet Orthop Soc 2011;22.

r.

Fitzpatrick N, Egan P. Clinical outcome of antebrachial growth deformity treated using true spherical osteotomy and internal fixation in 47 canine limbs (abstr), in Proceedings. 42nd Annu Conf Vet Orthop Soc 2015;27.

References

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    • Crossref
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  • 2. Dismukes DI, Tomlinson JL, Fox DB, et al. Radiographic measurement of canine tibial angles in the sagittal plane. Vet Surg 2008;37:300305.

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  • 3. Newman M, Voss K. Computed tomographic evaluation of femoral and tibial conformation in English Staffordshire Bull Terriers with and without congenital medial patellar luxation. Vet Comp Orthop Traumatol 2017;30:191199.

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  • 4. Nikolaou C, Black C, Ochoa JJ, et al. Guidelines for the execution of spherical osteotomies using a modified dome blade design. Vet Comp Orthop Traumatol 2020;33:7181.

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  • 5. Reid J, Nolan AM, Hughes JML, et al. Development of the short-form Glasgow Composite Measure Pain Scale (CMPS-SF) and derivation of an analgesic intervention score. Anim Welf 2007;16:97104.

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  • 6. Fitzpatrick N, Law AY, Bielecki M, et al. Cementless total hip replacement in 20 juveniles using BFX™ arthroplasty. Vet Surg 2014;43:715725.

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Contributor Notes

Dr. Sellier's present address is Centre Hospitalier Vétérinaire Frégis, 94110 Arcueil, France.

Address correspondence to Dr. Guthrie (JamesG@fitzpatrickreferrals.co.uk).
  • Figure 1—

    A 3-D reconstructed CT image of the left pelvic limb of a 6-month-old Miniature Dachshund that had lameness after exercise. A varus deformity with internal torsion of the distal aspect of the tibia is evident.

  • Figure 2—

    Preoperative caudocranial radiographs of the unaffected right (A) and affected left (B) tibias of the dog in Figure 1 depicting placement of joint orientation and mechanical axis lines for assessment of the varus deformity. Proximal and distal joint orientation lines (PJOL and DJOL, respectively) and the mechanical axis (MA) of the tibia were first plotted and used to measure the mechanical medial proximal tibial angle (mMPTA) and mechanical medial distal tibial angle (mMDTA) on the radiograph of the unaffected limb. These angles were then plotted according to the same anatomic landmarks on the radiograph of the affected limb, and the proximal and distal tibial axes (PTA and DTA, respectively) were used to identify the CORA and the degree of angular deformity to be corrected. L = Left. R = Right.

  • Figure 3—

    Preoperative mediolateral radiographs of the unaffected right (A) and affected left (B) tibias of the dog in Figure 1. The joint orientation and mechanical axis lines were plotted on the unaffected tibia for determination of the mechanical cranial proximal tibial angle (mCrPTA) and the mechanical cranial distal tibial angle (mCrDTA), which were then plotted on the radiograph of the affected tibia for determination of the CORA and degree of procurvatum to be corrected. See Figure 2 for remainder of key.

  • Figure 4—

    Intraoperative photographs (A and B) and immediate postoperative radiographs (C) of the dog in Figure 1. A—The affected limb was supported by an assistant as shown throughout the surgery. Abnormalities of the tibial region are grossly evident. B—Photograph of the TSO created with the 12-mm dome saw blade. C—Composite radiographic image (caudocranial and mediolateral views [left and right sides of the image, respectively]) showing alignment of the proximal and distal parts of the affected tibia and placement of implants.

  • Figure 5—

    Photographs obtained at a 6-week follow-up examination (A, B, and C) and caudocranial (D) and mediolateral (E) radiographs obtained at a 12-week follow-up examination for the same dog in Figure 1. Symmetry of the pelvic limbs was judged satisfactory. Osseous union had developed at the osteotomy site by week 12. See Figure 2 for key.

  • 1. Dismukes DI, Tomlinson JL, Fox DB, et al. Radiographic measurement of the proximal and distal mechanical joint angles in the canine tibia. Vet Surg 2007;36:699704.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 2. Dismukes DI, Tomlinson JL, Fox DB, et al. Radiographic measurement of canine tibial angles in the sagittal plane. Vet Surg 2008;37:300305.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3. Newman M, Voss K. Computed tomographic evaluation of femoral and tibial conformation in English Staffordshire Bull Terriers with and without congenital medial patellar luxation. Vet Comp Orthop Traumatol 2017;30:191199.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4. Nikolaou C, Black C, Ochoa JJ, et al. Guidelines for the execution of spherical osteotomies using a modified dome blade design. Vet Comp Orthop Traumatol 2020;33:7181.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 5. Reid J, Nolan AM, Hughes JML, et al. Development of the short-form Glasgow Composite Measure Pain Scale (CMPS-SF) and derivation of an analgesic intervention score. Anim Welf 2007;16:97104.

    • Search Google Scholar
    • Export Citation
  • 6. Fitzpatrick N, Law AY, Bielecki M, et al. Cementless total hip replacement in 20 juveniles using BFX™ arthroplasty. Vet Surg 2014;43:715725.

    • Search Google Scholar
    • Export Citation
  • 7. Johnson SG, Hulse DA, Vangundy TE, et al. Corrective osteotomy for pes varus in the Dachshund. Vet Surg 1989;18:373379.

  • 8. DeCamp CE, Johnston SA, Déjardin LM, et al. Correction of abnormal bone growth and healing. In: Brinker, Piermattei and Flo's handbook of small animal orthopedics and fracture repair. 5th ed. St Louis: Elsevier, 2016;791820.

    • Search Google Scholar
    • Export Citation
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