Tomás Guerrero

Force plate gait analysis to assess limb function after tibial tuberosity advancement in dogs with cranial cruciate ligament disease.

OBJECTIVE To assess functional outcome in dogs with cranial cruciate ligament (CrCL) disease after tibial tuberosity advancement (TTA) using force plate gait analysis, and to evaluate parameters potentially influencing outcome. STUDY DESIGN Prospective clinical study. ANIMALS Consecutive clinical patients (n = 37) with CrCL-deficient stifles (n = 40). METHODS The stifle joints were examined arthroscopically prior to TTA. Meniscal release was not performed if the medial meniscus was intact. Open medial arthrotomy and partial meniscectomy were performed in the presence of meniscal tears. Vertical ground reaction forces were measured preoperatively and at follow-up examinations four to 16 months postoperatively (mean: 5.9 months). The ground reaction forces of a group of 65 healthy dogs were used for the comparison. The potential effects of clinical parameters on functional outcome were evaluated statistically. RESULTS Complete CrCL rupture was identified in 28 joints, and partial CrCL rupture in 12 joints. The medial meniscus was damaged in 21 stifles. Vertical ground reaction forces were significantly higher at follow-up (P < 0.01), but remained significantly lower than those of control dogs (P < 0.01). Complications were identified in 25% of joints, and the dogs with complications had significantly lower peak vertical forces at follow-up than the dogs without complications (P = 0.04). Other clinical parameters did not influence outcome. CONCLUSIONS Tibial tuberosity advancement significantly improved limb function in dogs with CrCL disease, but did not result in complete return to function. Complications adversely affected functional outcome. CLINICAL SIGNIFICANCE A return to a function of approximately 90% of normal can be expected in dogs with CrCL disease undergoing TTA.

Zurich cementless total hip replacement: retrospective evaluation of 2nd generation implants in 60 dogs.

OBJECTIVE To evaluate the results of application, and identify complications, of the 2nd generation of Zurich Cementless Total Hip Replacement (ZCTHR). STUDY DESIGN Case series. ANIMALS Client-owned dogs (n=60) that had ZCTHR (n=65). METHODS Dogs with ZCTHR (2001-2003) with a minimum follow-up > or =6 months were evaluated. Data included signalment, cup position, longest follow-up, complications, management of complications and outcome. RESULTS Mean follow-up was 22.68 months. Eleven cases (17%) had postoperative complications: femoral fracture (n=1; 1.5%), prosthesis luxation (7; 11%), cup loosening (2; 3%), and implant failure (1; 1.5%); 9 cases were successfully revised. Explantation of implants was performed in 1 case because of infection, and 1 dog was euthanatized after reluxation. CONCLUSIONS ZCTHR can restore function in dogs affected by disabling diseases of the coxofemoral joint. The press-fit fixation of the cup allowed for corrections in cases of incorrect positioning. Cases with aseptic loosening were revised successfully by impacting larger cups. Newer stems of this generation are shot peening treated to increase their resistance to breakage. In our cases, infection is a disastrous event, leading to implant removal. After resolution of complications, a successful final outcome was achieved in 97% of THR. CLINICAL RELEVANCE ZCTHR offers a reliable alternative for treating dogs with disabling diseases of the hip joints.

Effect of tibial tuberosity advancement on femorotibial shear in cranial cruciate-deficient stifles An in vitro study

OBJECTIVES This in vitro study compares the femorotibial shear in canine stifles with intact and transected cranial cruciate ligaments (CrCL), before and after tibial tuberosity advancement (TTA) by measuring the distance between origin and insertion of the cruciate ligaments. METHODS Radiodense markers were inserted into bones at the attachment sites of the cruciate ligaments in sixteen cadaveric stifles of adult dogs. Each stifle was then mounted in a testing apparatus. The distances between the markers were measured on mediolateral radiographs, performed on each stifle under three different situations: intact, after CrCL transection, and after performing a TTA. Stifles were loaded to create a constant tibiofemoral reaction force by maintaining the load parallel to the patellar ligament. Radiographs were taken in a preloaded and loaded state in the intact stifle and only in a loaded state after CrCL transection, and after performing a TTA. RESULTS Loading the stifle joints after transection of the CrCL resulted in a mean lengthening of the CrCL marker distance of 22.4%. Loading the transected CrCL stifles after performing a TTA resulted in a mean shortening of the CrCL marker distance by 3.0% compared to the loaded intact condition. CLINICAL SIGNIFICANCE This study demonstrates that, in loaded stifles with transected CrCLs, TTA causes a caudal shift in the cranial shear force, counteracting cranial subluxation of the tibia.

Comparison of healing of the osteotomy gap after tibial tuberosity advancement with and without use of an autogenous cancellous bone graft

Objective: To evaluate and compare healing, with and without the use of bone graft, of the gap created during tibial tuberosity advancement (TTA). Study Design: Prospective study and case series. Animals: Dogs treated with TTA (n=67). Methods: Prospective study: Mediolateral radiographic projections (6 weeks and 4 months) after TTA without use of bone graft (group I, n=14) were compared with radiographs of consecutive TTA in which the gap was filled with autologous cancellous bone graft (group II, n=14). Two scoring techniques (A, B) were used. Score A was used to grade the overall osteotomy healing (0=no healing, 4=healed osteotomy). Score B evaluated, independently of each other, healing in 3 sites: proximal to the cage (B1), between cage and plate (B2), and distal to the plate (B3). Case series: nongrafted TTA (4–25 weeks, n=39) were evaluated for healing (Score A). Data was analyzed using t-tests and ANOVA. Significance was set at P≤.05. Results: Prospective study: Score A, B2, and B3 showed no difference in healing between groups at 6.8 weeks and 4.2 months. Score B1 revealed, in both rechecks, a significantly higher density in group II. Case series: Radiographs at 11.59±5.99 weeks scored 3.3 (2–4). No healing related complications were observed. Conclusion: The osteotomy gap created during TTA healed within expected time regardless of bone graft use.OBJECTIVE To evaluate and compare healing, with and without the use of bone graft, of the gap created during tibial tuberosity advancement (TTA). STUDY DESIGN Prospective study and case series. ANIMALS Dogs treated with TTA (n=67). METHODS Prospective study: Mediolateral radiographic projections (6 weeks and 4 months) after TTA without use of bone graft (group I, n=14) were compared with radiographs of consecutive TTA in which the gap was filled with autologous cancellous bone graft (group II, n=14). Two scoring techniques (A, B) were used. Score A was used to grade the overall osteotomy healing (0=no healing, 4=healed osteotomy). Score B evaluated, independently of each other, healing in 3 sites: proximal to the cage (B1), between cage and plate (B2), and distal to the plate (B3). CASE SERIES nongrafted TTA (4-25 weeks, n=39) were evaluated for healing (Score A). Data was analyzed using t-tests and ANOVA. Significance was set at P≤.05. RESULTS Prospective study: Score A, B2, and B3 showed no difference in healing between groups at 6.8 weeks and 4.2 months. Score B1 revealed, in both rechecks, a significantly higher density in group II. case series: Radiographs at 11.59±5.99 weeks scored 3.3 (2-4). No healing related complications were observed. CONCLUSION The osteotomy gap created during TTA healed within expected time regardless of bone graft use.

Effect of Tibial Tuberosity Advancement on the Contact Mechanics and the Alignment of the Patellofemoral and Femorotibial Joints

OBJECTIVE To evaluate the effect of tibial tuberosity advancement (TTA) on patellofemoral (PF) contact mechanics, and alignment of the PF and femorotibial (FT) joints in cranial cruciate ligament (CrCL)-deficient stifles of dogs. STUDY DESIGN Ex vivo biomechanical study. ANIMALS Unpaired cadaveric hind limbs (n=9). METHODS Digital pressure sensors placed in the PF joint were used to measure 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°. The FT and PF poses were obtained using a 2-dimensional computer digitization technique. Each specimen was tested under normal, CrCL-deficient, and TTA-treated conditions. Data was normalized and analyzed, after testing for normality by Wilk-Shapiro, using 1 sample T-test, paired T-test, and ANOVA; P≤.05 was considered significant. Bonferronis correction was used when needed. RESULTS A significant cranioproximal tibial displacement and increase in patellar tilt were found in the CrCL-deficient joints. Both FT and PF alignments were restored after TTA. Contact areas and peak pressure did not vary between conditions. Peak pressure location displaced proximally from intact to CrCL-deficient condition and returned to normal after TTA. Total force measured in the CrCL-deficient stifle and TTA conditions were significantly lower than in the control. CONCLUSION TTA restored the normal FT and PF alignment, and reduced the retropatellar force by about 20%.

Correlation of Radiographic Changes after Tibial Tuberosity Advancement in Dogs with Cranial Cruciate‐Deficient Stifles with Functional Outcome

Objective: To (1) evaluate radiographic changes associated with osteoarthrosis (OA) before and after tibial tuberosity advancement (TTA) and (2) determine if these changes are indicative of limb function as determined by kinetic gait analysis. Study Design: Prospective clinical study. Animals: Dogs (n=35) with cranial cruciate ligament (CCL) deficient stifles (38). Methods: Variables recorded were: complete or partial CCL rupture, meniscal lesions, arthroscopically graded cartilage lesions, complications, and revision surgeries. Radiographic evaluation and kinetic gait analysis (vertical ground reaction forces [GRFs]) were conducted pre- and 4–16 months postoperatively (mean, 5.9 months). Radiographs were evaluated without knowledge of operative findings and functional outcome. A score (0–3) based on new bone production at 11 specific sites was used to grade OA. Soft tissue changes were classified separately as normal or excessive. Preoperative scores were correlated with clinical variables. Postoperative scores and progression of OA scores were correlated with clinical variables and GRFs. Results: OA remained unchanged in 17 joints and progressed in 21 (55%). Dogs with meniscal lesions had higher OA scores preoperatively, but not at follow-up. Dogs with severe cartilage lesions at surgery had more progression of OA. GRFs improved after surgery and were not correlated with any of the radiographic OA scores. Conclusion: Progression of OA was greater in the presence of severe cartilage lesions at surgery. OA scores were not correlated with GRFs. Clinical Relevance: Progression of OA is generally expected to occur after TTA despite improvement of limb function.OBJECTIVE To (1) evaluate radiographic changes associated with osteoarthrosis (OA) before and after tibial tuberosity advancement (TTA) and (2) determine if these changes are indicative of limb function as determined by kinetic gait analysis. STUDY DESIGN Prospective clinical study. ANIMALS Dogs (n=35) with cranial cruciate ligament (CCL) deficient stifles (38). METHODS Variables recorded were: complete or partial CCL rupture, meniscal lesions, arthroscopically graded cartilage lesions, complications, and revision surgeries. Radiographic evaluation and kinetic gait analysis (vertical ground reaction forces [GRFs]) were conducted pre- and 4-16 months postoperatively (mean, 5.9 months). Radiographs were evaluated without knowledge of operative findings and functional outcome. A score (0-3) based on new bone production at 11 specific sites was used to grade OA. Soft tissue changes were classified separately as normal or excessive. Preoperative scores were correlated with clinical variables. Postoperative scores and progression of OA scores were correlated with clinical variables and GRFs. RESULTS OA remained unchanged in 17 joints and progressed in 21 (55%). Dogs with meniscal lesions had higher OA scores preoperatively, but not at follow-up. Dogs with severe cartilage lesions at surgery had more progression of OA. GRFs improved after surgery and were not correlated with any of the radiographic OA scores. CONCLUSION Progression of OA was greater in the presence of severe cartilage lesions at surgery. OA scores were not correlated with GRFs. CLINICAL RELEVANCE Progression of OA is generally expected to occur after TTA despite improvement of limb function.

RADIOGRAPHIC AND ULTRASONOGRAPHIC EVALUATION OF THE PATELLAR LIGAMENT FOLLOWING TIBIAL TUBEROSITY ADVANCEMENT

Effect of tibial tuberosity advancement (TTA) on the patellar ligament has not been described. Our purpose was to evaluate the patellar ligament radiographically and ultrasonographically before and after a TTA. Twenty-one stifles (20 dogs) were evaluated preoperatively (T0), and at six (n=18) (T1) and 16 weeks (n=17) (T2) postTTA. Radiographically, proximal and distal thickness of the patellar ligament was assessed and a ratio to the total length of the ligament was calculated to compensate for the magnification. Ultrasound evaluation included measurements of the transverse thickness and cross-sectional area at three different levels, as well as a subjective score of ligament changes. In comparison with T0, all radiographic and ultrasonographic measurements increased significantly, 6 weeks postoperatively (P≤0.04), and did not change 16 weeks postoperatively compared with T1. The subjective score worsened significantly from T0 to T1 and T0 to T2 (P<0.0001), and improved significantly from T1 to T2 (P=0.02). Larger cage size was associated with a more severe increase in radiographic proximal thickness to total length ratio and ultrasonographic middle transverse area at both follow-up examinations (P0.02). Dogs in which arthrotomy was not performed appeared to have ultrasonographically less changes. In conclusion, patellar desmopathy was a common postoperative sequel to TTA. Surgical trauma, arthrotomy, perfusion injury, complete vs. partial cranial cruciate ligament rupture, larger tibial advancement, postoperative activity or altered insertion angle of the patellar ligament at the tibial tuberosity are suggested causes, that should be elucidated in a larger study cohort.

Comparison between a novel bovine xenoimplant and autogenous cancellous bone graft in tibial tuberosity advancement.

OBJECTIVE To compare radiographic healing and clinical outcome of a frontal-opening wedge osteotomy of canine tibiae when the osteotomy site is packed with either a novel bovine xenograft or standard autogenous cancellous bone graft (ACBG). STUDY DESIGN Cohort study. ANIMALS Dogs (n = 82) with partial or complete rupture of the cranial cruciate ligament that had tibial tuberosity advancement (TTA). METHODS In 48 dogs, the osteotomy was packed with a novel bovine xenograft and in 34 dogs, ACBG was used. Eight week postoperative radiographs from both groups were graded for osteotomy healing using a 0-4-point scale. Data were analyzed using a Mann-Whitney test with significance set at P < .05. RESULTS Thirty-four dogs (39 stifles) with xenoimplants had complete records and radiographic follow-up at 8 weeks. No significant differences between xenografting and autografting were identified in grading of osteotomy fill, osteointegration, or healing of the distal osteotomy. Significant differences were noted in grading of osteotomy healing proximally (autograft > xenoimplant) and of opacity in the osteotomy site (xenoimplant > autograft). CONCLUSIONS Radiographic evidence of healing of the xenoimplanted portion of the TTA osteotomy was equivalent to results with ACBG. Healing of the proximal osteotomy site (above the cage) was improved when ACBG was used as the graft.

Effect of External Rotational Humeral Osteotomy on the Contact Mechanics of the Canine Elbow Joint

OBJECTIVE To evaluate the effect of 15° external rotational humeral osteotomy (ERHO) on canine elbow joint contact mechanics. STUDY DESIGN Ex vivo biomechanical study. SAMPLE POPULATION Unpaired cadaveric canine thoracic limbs (n = 8) METHODS Digital pressure sensors placed in a subchondral osteotomy distal to the elbow joint were used to measure contact area, peak and mean contact pressure, peak pressure location, center of pressure, and total force in the subchondral bone of the radius and the ulna. Measurements were taken in the following sequence: (i) neutral and (ii) after 15° external rotation. The distal aspect of the humerus was externally rotated by a middiaphyseal osteotomy and stabilized with an internal fixator. Data were normalized and analyzed using paired t-tests; P ≤ .05 was considered significant. RESULTS Peak pressure location and center of pressure shifted 37.5 ± 15.9% and 21.5 ± 6.8% laterally after ERHO (P < .001 for both). Both were situated over the subchondral bone of the ulna in neutral position and over the radius after rotation in all 8 specimens (P < .001). Pressure measured in the ulnar part of the osteotomy was reduced from 58.7 ± 9.1% to 27.1% after ERHO (P < .001). Contact area, peak and mean contact pressure, and total force did not vary significantly between conditions. CONCLUSION ERHO shifts the peak pressure location and the center of pressure laterally, toward the radial head and reduced the pressure acting on the ulna. The lateral shift of peak pressure may be beneficial in dogs with medial compartment disease.

Temporary transarticular stabilization with a locking plate for medial shoulder luxation in a dog

This report describes the temporary fixation of a traumatic shoulder luxation in a large-breed dog using a 3.5-mm Locking Round-Hole Reconstruction Plate (LRHRP) to provide stable internal splinting, allowing healing of the injured ligaments, joint capsule, glenohumeral ligaments, tendons, and muscles for restoration of joint stability. The use of a temporary plate with a locking system should be considered as an option in the treatment of canine shoulder joint luxations with severe tissue damage.