Antonio Pozzi

Tibial Osteotomies for Cranial Cruciate Ligament Insufficiency in Dogs

OBJECTIVE To review the biomechanical considerations, experimental investigations, and clinical data pertaining to tibial osteotomy procedures for treatment of cranial cruciate ligament (CrCL) insufficiency in dogs. STUDY DESIGN Literature review. METHODS Literature search through Pub Med, Veterinary Information Network, Commonwealth Agricultural Bureau Abstracts, and conference proceedings abstracts (November 1977 to March 2007). RESULTS Reported tibial osteotomy procedures attempt to eliminate sagittal instability (cranial tibial thrust) in CrCL-deficient stifles by altering the conformation of the proximal tibia. Functional stability can be achieved by decreasing the tibial plateau slope (cranial tibial closing wedge osteotomy [CTWO], tibial plateau leveling osteotomy [TPLO], combined TPLO and CTWO, proximal intraarticular osteotomy, chevron wedge osteotomy), altering the alignment of the patellar tendon (tibial tuberosity advancement), or both (triple tibial osteotomy). Clinical reports assessing the efficacy of these procedures frequently use subjective outcome measures, and the periods of follow-up evaluation are highly variable. Satisfactory results have been reported in most (>75%) dogs irrespective of the type of tibial osteotomy procedure. CONCLUSIONS Currently available data does not allow accurate comparisons between different tibial osteotomy procedures, or with traditional methods of stabilizing the CrCL-deficient stifle. Carefully designed long-term clinical studies and further biomechanical analyses are required to determine the optimal osteotomy technique, and whether these procedures are superior to other stabilization methods. CLINICAL RELEVANCE Limb function in dogs with CrCL insufficiency can be improved using the currently described tibial osteotomy techniques.

Proposed Definitions and Criteria for Reporting Time Frame, Outcome, and Complications For Clinical Orthopedic Studies in Veterinary Medicine

Outcome, and Complications For Clinical Orthopedic Studies in Veterinary Medicine James L. Cook, DVM, PhD, Diplomate ACVS, Richard Evans, PhD, Michael G. Conzemius, DVM, PhD, Diplomate ACVS, B. Duncan X. Lascelles, BVSc, PhD, Diplomate ECVS, Diplomate ACVS, C. Wayne McIlwraith, BVSc, PhD, Diplomate ACVS, Antonio Pozzi, DMV, MS, Diplomate ACVS, Peter Clegg, MA, VetMB, PhD, Diplomate ECVS, MRCVS, John Innes, BVSc, PhD, DSAS (Orth), MRCVS, Kurt Schulz, DVM, Diplomate ACVS, John Houlton, MA, VetMB, DVR, DSAO, MRCVS, Diplomate ECVS, Lisa Fortier, DVM, PhD, Diplomate ACVS, Alan R. Cross, DVM, Diplomate ACVS, Kei Hayashi, DVM, PhD, Diplomate ACVS, Amy Kapatkin, DVM, MS, Diplomate ACVS, Dorothy Cimino Brown, DVM, MSCE, Diplomate ACVS, and Allison Stewart, DVM, MS, Diplomate ACVS Comparative Orthopaedic Laboratory, University of Missouri, Columbia, MO, College of Veterinary Medicine, University of Illinois, Urbana, IL, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, Comparative Pain Research Laboratory, North Carolina State University,

Comparison of arthroscopy and arthrotomy for diagnosis of medial meniscal pathology: an ex vivo study.

OBJECTIVE To evaluate the sensitivity and specificity of arthroscopy and arthrotomy for diagnosis of medial meniscal pathology and to evaluate the diagnostic value of medial meniscal probing. STUDY DESIGN Ex vivo study. ANIMALS Cadaveric canine stifle joints (n=30). METHODS Stifle joints were assigned to either a cranial cruciate ligament (CrCL) deficient or intact group. Within each stifle joint, no medial meniscal tear, a peripheral detachment, or 1 of 3 variants of vertical longitudinal tears of the medial meniscus were created. Each stifle joint had arthroscopy, craniomedial (CrMed), and caudomedial (CdMed) arthrotomy. Diagnoses were made by both observation and probing. Sensitivity, specificity, and correct classification rate (CCR) for diagnosing the state of the medial meniscus using both observation and probing with all diagnostic methods were calculated. Odds ratios were calculated to determine if probing increased diagnostic accuracy. RESULTS Arthroscopy with probing was the most sensitive and specific diagnostic method and had the highest CCR. For arthrotomy, CrMed was the most sensitive in CrCL-deficient and CdMed the most sensitive in stable, CrCL-intact stifle joints. For all methods, probing increased their diagnostic accuracy. CONCLUSIONS Arthroscopy is the most accurate diagnostic method; however, probing the medial meniscus enhances the diagnostic accuracy of all methods. CLINICAL RELEVANCE Accurate diagnosis of medial meniscal pathology is ideally achieved by means of arthroscopy; however, if arthrotomy is chosen, CrMed should be selected in unstable and CdMed in stable stifle joints. Regardless, medial meniscal probing should be performed to increase diagnostic accuracy.

Effect of tibial plateau leveling osteotomy on femorotibial contact mechanics and stifle kinematics.

OBJECTIVE To evaluate the effects of tibial plateau leveling osteotomy (TPLO) on femorotibial contact mechanics and 3-dimensional (3D) kinematics in cranial cruciate ligament (CrCL)-deficient stifles of dogs. STUDY DESIGN In vitro biomechanical study. ANIMALS Unpaired pelvic limbs from 8 dogs, weighing 28-35 kg. METHODS Digital pressure sensors placed subjacent to the menisci were used to measure femorotibial contact force, contact area, peak and mean contact pressure, and peak pressure location with the limb under an axial load of 30% body weight and a stifle angle of 135 degrees. Three-dimensional static poses of the stifle were obtained using a Microscribe digitizing arm. Each specimen was tested under normal, CrCL-deficient, and TPLO-treated conditions. Repeated measures analysis of variance with a Tukey post hoc test (P<.05) was used for statistical comparison. RESULTS Significant disturbances to all measured contact mechanical variables were evident after CrCL transection, which corresponded to marked cranial tibial subluxation and increased internal tibial rotation in the CrCL-deficient stifle. No significant differences in 3D femorotibial alignment were observed between normal and TPLO-treated stifles; however, femorotibial contact area remained significantly smaller and peak contact pressures in both medial and lateral stifle compartments were positioned more caudally on the tibial plateau, when compared with normal. CONCLUSION Whereas TPLO eliminates craniocaudal stifle instability during simulated weight bearing, the procedure fails to concurrently restore femorotibial contact mechanics to normal. CLINICAL RELEVANCE Progression of stifle osteoarthritis in dogs treated with TPLO may be partly the result of abnormal stifle contact mechanics induced by altering the orientation of the proximal tibial articulating surface.

Effect of Tibial Tuberosity Advancement on Femorotibial Contact Mechanics and Stifle Kinematics

Objective- To evaluate the effects of tibial tuberosity advancement (TTA) on femorotibial contact mechanics and 3-dimensional kinematics in cranial cruciate ligament (CrCL)-deficient stifles of dogs. Study Design- In vitro biomechanical study. Animals- Unpaired pelvic limbs from 8 dogs, weighing 28-35 kg. Methods- Digital pressure sensors placed subjacent to the menisci were used to measure femorotibial contact force, contact area, peak and mean contact pressure, and peak pressure location with the limb under an axial load of 30% body weight and a stifle angle of 135 degrees . Three-dimensional static poses of the stifle were obtained using a Microscribe digitizing arm. Each specimen was tested under normal, CrCL-deficient, and TTA-treated conditions. Repeated measures analysis of variance with a Tukey post hoc test (P<.05) was used for statistical comparison. Results- Significant disturbances to all measured contact mechanic parameters were evident after CrCL transection, which corresponded to marked cranial tibial subluxation and internal tibial rotation in the CrCL-deficient stifle. No significant differences in any contact mechanic and kinematic parameters were detected between normal and TTA-treated stifles. Conclusion- TTA eliminates craniocaudal stifle instability during simulated weight-bearing and concurrently restores femorotibial contact mechanics to normal. Clinical Relevance- TTA may mitigate the progression of stifle osteoarthritis in dogs afflicted with CrCL insufficiency by eliminating cranial tibial thrust while preserving the normal orientation of the proximal tibial articulating surface.

Pressure distributions on the medial tibial plateau after medial meniscal surgery and tibial plateau levelling osteotomy in dogs

OBJECTIVE To evaluate the effect of medial meniscal release (MMR) and medial, caudal pole hemimeniscectomy (MCH) on pressure distribution in the cranial cruciate ligament (CCL) deficient canine stifle, and with tibial plateau levelling osteotomy (TPLO). ANIMALS Twelve adult dogs. METHODS In experiment one, six pairs of cadaveric canine stifles with an intact CCL were axially loaded with a servo-hydraulic material testing machine and pressure distributions were mapped and quantified using pressure sensitive films. Axial loading of each joint was then repeated following MMR, and again after MCH. In experiment two, six pairs of cadaveric canine stifles with or without TPLO were tested before and after CCL transection, and each MMR and MCH procedure using the same methods of experiment 1. RESULTS In experiment one, MMR and MCH had significant effects on the pressure distribution resulting in a 2.5-fold increase in the percentage of surface area with pressure higher than 10 MPa. In experiment two, CCL transection resulted in a significant change in pressure distribution only in the stifle without TPLO (P<0.05). Both MMR and MCH resulted in a 1.7-fold increase in the percentage of area with peak pressure in the stifle with TPLO (P<0.05). CONCLUSIONS Meniscal surgery results in a change in pressure distribution and magnitude within the medial compartment of the stifle. CLINICAL RELEVANCE Compromised function of the meniscus by either MMR or MCH result in stress concentration which may predispose to osteoarthritis.

Minimally invasive plate osteosynthesis: Applications and techniques in dogs and cats

Bone plating has been used as a method of fracture management for many years. Recently, a trend toward the use of fracture fixation techniques which preserve the local fracture environment, known as biological osteosynthesis, has evolved. This trend has resulted in the development of a less traumatic method of bone plating referred to as minimally invasive plate osteosynthesis (MIPO), or percutaneous plating. During MIPO fracture stabilisation, plates are inserted through short incisions and a communicating epiperiosteal tunnel. Typically, bone plates applied in this fashion have a bridging function. Promising outcomes have been reported in human patients undergoing MIPO fracture stabilisation, and limited reports of the use of this technique in dogs and cats have yielded positive results as well. Careful case selection, pre-operative planning, and appropriate instrumentation are necessary when performing the technique. Rapid time to union, low complication rates and good return to function have been noted in human patients. Additional research is needed to define selection criteria and outline the definitive benefits of MIPO in dogs and cats.

Effect of tibial plateau leveling osteotomy on femorotibial subluxation: in vivo analysis during standing.

OBJECTIVE To assess the effect of tibial plateau leveling osteotomy (TPLO) on femorotibial subluxation during standing in dogs with cranial cruciate ligament (CrCL) insufficiency. STUDY DESIGN Prospective clinical study. ANIMALS Fifteen dogs weighing 20-45 kg with unilateral complete CrCL insufficiency. METHODS Force-platform analysis, and lateral weight-bearing radiographs of the affected stifle were acquired preoperatively, 1, 3, and 6 months postoperatively. The distance between the origin and insertion of the CrCL (CrCL(d) ) was measured on each radiograph and compared between time points using ANOVA. Lateral radiographs of the non-weight-bearing affected stifle and weight-bearing contralateral normal stifle were acquired preoperatively, and CrCL(d) was compared with a paired t-test. Dogs were grouped according to medial meniscal status (intact or hemimeniscectomy) and CrCL(d) was compared within each group using ANOVA. RESULTS No difference was observed in CrCL(d) between the non-weight-bearing affected stifle and the contralateral stifle (P = .994). That is, femorotibial joint alignment in the affected stifle when non-weight-bearing was considered normal. Preoperatively in the affected stifle, CrCL(d) during weight-bearing was 6.3 ± 2.4 mm longer than normal (P < .001). Postoperative weight-bearing CrCL(d) in dogs with intact menisci at all time points was not statistically different from normal; CrCL(d) at 1 (P = .014) and 6 months (P = .005) postoperatively was longer than normal in dogs with hemimeniscectomy. CONCLUSIONS TPLO does not consistently resolve femorotibial subluxation during standing in dogs with CrCL insufficiency. The medial meniscus appears to be an important contributor to stability in stifles treated by TPLO.

Retrospective Comparison of Minimally Invasive Plate Osteosynthesis and Open Reduction and Internal Fixation of Radius‐Ulna Fractures in Dogs

OBJECTIVE To compare the efficacy of reduction, time to union, and clinical outcome of radius and ulna fractures stabilized using either minimally invasive plate osteosynthesis (MIPO) or open reduction and internal fixation (ORIF). STUDY DESIGN Retrospective, case-controlled study. ANIMALS Dogs with radius and ulna fractures stabilized with plates applied using MIPO (n = 15) or ORIF (n = 15). METHODS Dogs in each stabilization group were matched for type and location of fracture, age, and body weight. Outcome measures including surgical time, fracture alignment, gap width, plate length, plate bridging and span ratio, working length and screw density, and time to union were compared between the groups using an unpaired t-test. Statistical significance was set at P < .05. RESULTS All fractures obtained radiographic union although infection developed in 1 dog in each stabilization group. Dogs treated with MIPO had a significant longer plate working length and lesser screw-density (P < .05). No statistical difference was found in operating time, postoperative alignment, gap width, or time to union (MIPO: 51.9 ± 18.4 days; ORIF: 49.5 ± 26.5 days). CONCLUSIONS Radius and ulna fractures managed with MIPO had similar alignment, reduction, and time to union as fractures managed with ORIF. Future prospective clinical studies are warranted and should assess healing more frequently and in a standardized manner to compare MIPO to ORIF in a larger population of dogs.Objective To compare the efficacy of reduction, time to union, and clinical outcome of radius and ulna fractures stabilized using either minimally invasive plate osteosynthesis (MIPO) or open reduction and internal fixation (ORIF). Study Design Retrospective, case-controlled study. Animals Dogs with radius and ulna fractures stabilized with plates applied using MIPO (n = 15) or ORIF (n = 15). Methods Dogs in each stabilization group were matched for type and location of fracture, age, and body weight. Outcome measures including surgical time, fracture alignment, gap width, plate length, plate bridging and span ratio, working length and screw density, and time to union were compared between the groups using an unpaired t-test. Statistical significance was set at P < .05. Results All fractures obtained radiographic union although infection developed in 1 dog in each stabilization group. Dogs treated with MIPO had a significant longer plate working length and lesser screw-density (P < .05). No statistical difference was found in operating time, postoperative alignment, gap width, or time to union (MIPO: 51.9 ± 18.4 days; ORIF: 49.5 ± 26.5 days). Conclusions Radius and ulna fractures managed with MIPO had similar alignment, reduction, and time to union as fractures managed with ORIF. Future prospective clinical studies are warranted and should assess healing more frequently and in a standardized manner to compare MIPO to ORIF in a larger population of dogs.

Effect of cold compression therapy on postoperative pain, swelling, range of motion, and lameness after tibial plateau leveling osteotomy in dogs

OBJECTIVE To evaluate the effect of cold compression therapy (CCT) on postoperative pain, lameness, range of motion of the stifle joint, and swelling following tibial plateau leveling osteotomy (TPLO) in dogs. DESIGN Randomized, blinded, placebo-controlled clinical trial. ANIMALS 34 client-owned dogs with unilateral deficiency of a cranial cruciate ligament undergoing TPLO. PROCEDURES Dogs were assigned to 2 groups. Group 1 (n = 17 dogs) received CCT in the 24-hour period following TPLO. Group 2 (n = 17 dogs) received no CCT. Degree of lameness, range of motion, and circumference of the stifle joint were measured before surgery and 1,14, and 28 days after surgery. A modified composite Glasgow pain scale, visual analogue scale, and pain threshold score were used to evaluate signs of pain before surgery and 1,14, and 28 days after surgery. Logistic regression and linear regression analysis were used to compare the measured variables. RESULTS No complications were observed, and all dogs tolerated CCT. Use of CCT resulted in lower values for the visual analogue scale and Glasgow pain scale and lower pain threshold scores; lower lameness scores; less swelling; and an increased range of motion 24 hours after surgery. At 14 days after surgery, there were no significant differences between groups. At 28 days after surgery, too few data sets were available for comparison. CONCLUSIONS AND CLINICAL RELEVANCE CCT decreased signs of pain, swelling, and lameness and increased stifle joint range of motion in dogs during the first 24 hours after TPLO.