An Evaluation of Three Different Cranial Cruciate Ligament Surgical Stabilization Procedures As They Relate to Postoperative Meniscal Injuries

Feasibility and cartilage injury of an all-inside arthroscopic meniscal repair application in a canine cadaveric study

Meniscal injury is the most common comorbidity in canine stifles with cranial cruciate ligament (CCL) pathology. Arthroscopic repair for acute tears can be technically challenging and is rarely described. This study evaluates the feasibility of using an all-inside arthroscopic meniscal repair device, Arthrex Meniscal Cinch II™ (MCII) in canine cadaveric stifles and the associated risks of iatrogenic vascular injury (IVI) and cartilage injury (ICI). 20 healthy paired canine cadaveric stifles (25 - 45 kg BW) were divided randomly into two groups of 10. Both groups received transection of the CCL via mini arthrotomy, joint distraction and diagnostic arthroscopy with meniscal probing. No further procedures were performed in the control group whereas the implant group underwent placement of the MCII-implants in the caudal horn of the medial meniscus. Angiography of the femoral artery was performed for each limb before and after operation and vascular trauma was assessed on radiographs. After disarticulation, the cartilage was stained via Indian ink assay and underwent blinded scoring for ICI. Implants were evaluated for desired position. Correct position of the MCII-implants was achieved in all stifles. No IVI was detected. Implant placement created more ICI on the medial femoral condyle (1.33 mm2) than arthroscopy alone (0.15 mm2) (p = 0.03). Implant associated complications occurred in 30 %. Arthroscopic use of MCII is feasible and carries minimal risk for vascular damage. Despite joint distraction, implant placement using the MCII is associated with significant cartilage damage. Although technically challenging, all-inside meniscal repair appears to carry limited risk in canine patients over 25 kg bodyweight.

Arthroscopy and arthrotomy were equally effective for medial meniscal release but arthroscopy was minimally advantageous at preventing iatrogenic damage to the caudal cruciate ligament: a canine cadaveric study

Objective

To compare efficacy of four techniques used for medial meniscal release by medial caudal meniscotibial ligament transection and evaluate associated iatrogenic damage to the medial meniscus, caudal cruciate ligament (CdCL), and articular cartilage of the canine stifle joint.

Study design

Twenty-four pairs of canine cadaveric pelvic limbs were randomly assigned to groups by methods of approach, cranial tibial translation, and meniscal release. I: arthrotomy, Hohmann, #11 scalpel blade; II: arthrotomy, Hohmann, #64 Beaver blade; III: arthroscopy, Hohmann, meniscal hook knife; IV: arthroscopy, no joint translation, meniscal hook knife. Post-procedure stifle dissection and evaluation of meniscal release success rate and presence of iatrogenic damage were performed. Fisher's exact tests were performed for meniscal release and damage comparisons. Iatrogenic damage to the CdCL and articular cartilage were compared using generalized linear mixed effects model and linear mixed effects models (G/LMM) respectively.

Results

Incomplete meniscal release was identified in 0/12 (0%) stifles in group I, 1/12 (8.3%) stifles in group II, 2/12 (16.7%) stifles in group III, and 1/12 (8.3%) stifles in group IV (p = 0.89, Fisher's exact test). There was no difference in iatrogenic meniscal damage rates between groups (p = 0.48, Fisher's exact test). There were no differences in total surface area of iatrogenic articular cartilage damage in any tested region between groups: femoral trochlea (p = 0.32, LMM), femoral condyles (p = 0.54, LMM), tibia (p = 0.28, LMM). Group I had more iatrogenic damage to the CdCL than group IV (p = 0.04, GLMM); no other differences were found.

Conclusion

Arthroscopy and arthrotomy were equally effective for performing medial meniscal release by transection of the medial caudal meniscotibial ligament. Arthroscopic evaluation and medial meniscal release without joint translation was minimally advantageous in preventing iatrogenic damage to the CdCL.

Medial joint line tenderness is an indicator for meniscal injuries in dogs

BACKGROUND

Medial meniscal injury is an important aspect of cranial cruciate ligament disease in dogs. This study examines whether caudomedial joint line palpation of the stifle is correlated with medial meniscal injury in canine stifles with concurrent cranial cruciate ligament disease.

METHODS

A total of 91 dogs (97 stifles) presenting with cranial cruciate ligament disease were assessed by palpation of the caudomedial joint line of the affected stifle by a single surgeon. Surgery was then performed to assess for injury to the medial meniscus. The odds of dogs with pain on palpation having a medial meniscal tear were then calculated, with the significance level set at p-value of 0.05.

RESULTS

Dogs showing pain on caudomedial joint palpation had 34.5 times (95% confidence interval 9.7‒125) greater odds of having a medial meniscal tear. Pain on caudomedial joint line palpation had a sensitivity of 0.86, specificity of 0.85, positive predictive value of 0.94, negative predictive value of 0.70 and accuracy of 0.86 for identifying dogs with a medial meniscal tear.

LIMITATIONS

The amount of pressure placed on the caudomedial joint line was not assessed and a control group was not included.

CONCLUSION

Medial joint line tenderness has a significant relationship with medial meniscal tear in dogs with cranial cruciate ligament disease.

Determining predictive metabolomic biomarkers of meniscal injury in dogs with cranial cruciate ligament rupture

OBJECTIVES

This study used hydrogen nuclear magnetic resonance spectroscopy for the first time to examine differences in the metabolomic profile of stifle joint synovial fluid from dogs with cranial cruciate ligament rupture with and without meniscal injuries, in order to identify biomarkers of meniscal injury. Identifying a biomarker of meniscal injury could then ultimately be used to design a minimally invasive diagnostic test for meniscal injuries in dogs.

MATERIALS AND METHODS

Stifle joint synovial fluid was collected from dogs undergoing stifle joint surgery or arthrocentesis for lameness investigations. We used multi-variate statistical analysis using principal component analysis and univariate statistical analysis using one-way analysis of variance and analysis of co-variance to identify differences in the metabolomic profile between dogs with cranial cruciate ligament rupture and meniscal injury, cranial cruciate ligament rupture without meniscal injury, and neither cranial cruciate ligament rupture nor meniscal injury, taking into consideration clinical variables.

RESULTS

A total of 154 samples of canine synovial fluid were included in the study. Sixty-four metabolites were annotated to the hydrogen nuclear magnetic resonance spectroscopy spectra. Six spectral regions were found to be significantly altered (false discovery rate adjusted P-value <0.05) between groups with cranial cruciate ligament rupture with and without meniscal injury, including three attributed to nuclear magnetic resonance mobile lipids [mobile lipid -CH3 (P=0.016), mobile lipid -n(CH3 )3 (P=0.017), mobile unsaturated lipid (P=0.031)].

CLINICAL SIGNIFICANCE

We identified an increase in nuclear magnetic resonance mobile lipids in the synovial fluid of dogs with meniscal injury which are of interest as potential biomarkers of meniscal injury.

Comparison of incidence of medial meniscal injury in small dogs (≤15 kg) and medium-to-large dogs (>15 kg) with naturally occurring cranial cruciate ligament disease undergoing tibial plateau levelling osteotomy: 580 stifles (2015 to 2019)

OBJECTIVES

To investigate whether a difference exists in incidence of medial meniscal tears between small (≤15 kg) and medium-to-large (>15 kg) dogs with naturally occurring cranial cruciate ligament disease.

MATERIALS AND METHODS

Records were retrospectively reviewed to identify the incidence of medial meniscal tears in dogs undergoing tibial plateau levelling osteotomy. Degree of cruciate insufficiency, method of identification (arthroscopy or arthrotomy), tibial plateau angle, weight and signalment were recorded. A two-proportion z-test with clustering adjustment was used to compare the meniscal tear rate between the two groups. Logistic regression analysis was used to investigate the effects of variables on medial meniscal tears.

RESULTS

Seventy-six stifles in 67 small dogs and 504 stifles in 384 medium-to-large dogs were included. The rate of meniscal injury at index surgery was 38.2% in small dogs and 36.7% in medium-to-large dogs. The subsequent meniscal tear rate was 1.3% in small dogs and 8% in medium-to-large dogs. The difference in meniscal tear rate was not statistically significant at either index surgery or subsequently. Degree of cruciate ligament insufficiency and use of arthroscopy were significantly associated with medial meniscal tears at index surgery. No variables were significantly associated with subsequent medial meniscal tears.

CLINICAL SIGNIFICANCE

No significant difference exists in medial meniscal tear rate between small and medium-to-large dogs either at index surgery or subsequently. The index of suspicion of concurrent medial meniscal tears should be higher in dogs with complete tear of the cranial cruciate ligament but a partial tear does not preclude meniscal pathology.

Use of Blumensaat's line for assessment of cranial tibial subluxation in dogs with cranial cruciate ligament deficiency

BACKGROUND

This study aimed to determine whether Blumensaat's line, a consistently present radiographic feature delineating the peak of the femoral intercondylar fossa, could be used to assess for cranial tibial subluxation in canine stifles with cranial cruciate ligament disease.

METHODS

Thirty sequential, neutrally positioned, standing-angle stifle radiographs were taken from dogs presenting to a specialist referral centre for treatment of cruciate ligament disease. Thirty similarly positioned radiographs of healthy canine stifles were used as a control group. The radiographs were anonymised and submitted to blinded observers for measurement of the tibial plateau angle, patella tendon angle, Blumensaat's line length and the length of Blumensaat's line cranial to the tibial mechanical axis.

RESULTS

Finding that the tibial mechanical axis intersects Blumensaat's line cranial to its midpoint, as a marker of cranial tibial subluxation, had a positive predictive value of 76% for subsequent surgical identification of cruciate ligament disease.

CONCLUSIONS

Tibial cranial subluxation is detectable and quantifiable radiographically using the intersection of the tibial mechanical axis and Blumensaat's line. Once quantified, this measurement could be used both as a radiographic marker of cruciate ligament disease and to adjust tibial osteotomy procedures to minimise the risk of under advancement of the tibial tuberosity resulting in a persistently unstable stifle.

The significance of the meniscal flounce sign in canine stifle arthroscopy

OBJECTIVE

To determine the diagnostic significance of the meniscal flounce sign in association with meniscal tears.

STUDY DESIGN

Prospective cohort study.

SAMPLE POPULATION

One hundred and thirty stifles in 120 client-owned dogs that underwent stifle arthroscopy.

METHODS

Identification of a positive or negative meniscal flounce sign was recorded with the presence or absence of meniscal pathology. Sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy were calculated.

RESULTS

Eighty-nine stifles (68.5%) were noted to have a positive meniscal flounce sign. Of these stifles, four were noted to have a meniscal tear, and they were all radial tears. A total of 41 stifles (31.5%) had a negative meniscal flounce. Of these stifles, 38 had a meniscal tear. The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of the meniscal flounce sign for indicating an intact or torn meniscus were 96.6%, 90.5%, 95.5%, 92.7%, and 94.6%, respectively.

CONCLUSION

A positive meniscal flounce sign was associated with a normal meniscus and the absence of the flounce sign was associated with a meniscal tear.

CLINICAL SIGNIFICANCE

Identification of the meniscal flounce sign during stifle arthroscopy is a strong indicator of a normal medial meniscus. The absence of the sign strongly indicates the presence of meniscal pathology.

Comparison of ultrasonography and magnetic resonance imaging to arthroscopy for diagnosing medial meniscal lesions in dogs with cranial cruciate ligament deficiency

OBJECTIVE To compare the accuracy of ultrasonography and MRI for diagnosing medial meniscal lesions in dogs with cranial cruciate ligament (CCL) deficiency. DESIGN Diagnostic test evaluation. ANIMALS 26 dogs (31 stifle joints) with CCL deficiency. PROCEDURES A single surgeon physically examined each dog and performed ultrasonography and arthroscopy of affected stifle joints to identify medial meniscal lesions. Video recordings of the arthroscopic procedure were saved and subsequently reviewed by the same surgeon and by a second surgeon working independently and blinded to results of all examinations. A radiologist blinded to results of all examinations evaluated MRI scans of the affected joints. Correct classification rate (CCR), sensitivity, and specificity of ultrasonography and MRI were calculated twice, with each of the 2 surgeons' arthroscopic assessments used as the reference standard. RESULTS Compared with arthroscopic examination by the unblinded surgeon, ultrasonography had a CCR of 90%, sensitivity of 95% (95% confidence interval [CI], 73% to 100%), and specificity of 82% (95% CI, 48% to 97%). For MRI, these values were 84%, 75% (51% to 90%), and 100% (68% to 100%), respectively. Compared with arthroscopic assessment by the blinded surgeon, ultrasonography had a CCR of 84%, sensitivity of 86% (95% CI, 64% to 96%), and specificity of 78% (95% CI, 40% to 96%). For MRI, these values were 77%, 68% (45% to 82%), and 100% (63% to 100%), respectively. CONCLUSIONS AND CLINICAL RELEVANCE These data suggested imperfect performance but clinical usefulness of both ultrasonography and MRI for diagnosing medial meniscal lesions in dogs.

Magnetic resonance imaging for detection of late meniscal tears in dogs following tibial tuberosity advancement for treatment of cranial cruciate ligament injury

To document the use of and to estimate the accuracy of magnetic resonance (MR) imaging for detection of late meniscal tears in dogs with cranial cruciate ligament injury treated with tibial tuberosity advancement (TTA).

Medical records of dogs that had TTA followed by stifle MR imaging for suspected meniscal tear and subsequent arthrotomy were reviewed retrospectively. Magnetic resonance images were reviewed independently by an observer blinded to clinical information who classified menisci as torn, abnormal but intact, or normal. Magnetic resonance and surgical findings were compared.

Eight stifles from large breed dogs were included. Six stifles had a medial meniscal tear identified in MR images and later confirmed surgically. In the remaining two stifles, the menisci appeared intact in MR images and no tear was identified at subsequent arthrotomy. Lateral menisci in all stifles appeared intact in MR images and were considered normal at surgery. Susceptibility artefacts associated with TTA implants were present in all images but did not adversely affect interpretation of intra-articular structures.

Magnetic resonance imaging appears to be accurate for diagnosis of late meniscal tears. Artefacts associated with TTA implants did not prevent evaluation of critical intra-articular structures. Further investigation with MR imaging should be considered when late meniscal tear is suspected following TTA.

Detection of meniscal tears by arthroscopy and arthrotomy in dogs with cranial cruciate ligament rupture

Objectives: To evaluate and compare detection of meniscal tears associated with cranial cruciate ligament insufficiency by either arthroscopy or arthrotomy.

Methods: A retrospective, cohort study was completed with stifles (n = 531) of dogs with cranial cruciate ligament rupture. Either a medial parapatellar arthrotomy or an arthroscopy procedure was performed and groups were compared for significant differences in meniscal tears detected using logistic regression analysis.

Results: Arthroscopy was performed on 58.8% and arthrotomy on 41.2% of the stifles. In total, 44.4% of the examined stifles had meniscal tears. Meniscal tears were found in 38.8% of the stifles examined by arthrotomy, and 48.4% of those examined by arthroscopy. Overall, the rate of detection of a meniscal tear was significantly different (p = 0.019) between the groups, and meniscal tears were observed more frequently by arthroscopy than by arthrotomy (odds ratio 1.54; 95% confidence interval 1.07 – 2.22).

Clinical significance: These results suggest that arthroscopy may be more sensitive than arthrotomy for detection of meniscal pathology in clinical patients. However, these results must be interpreted with caution since this was a retrospective study. Randomized prospective clinical studies are required to further test this hypothesis.

Computer-assisted gait analysis of the dog: Comparison of two surgical techniques for the ruptured cranial cruciate ligament

Objectives: To compare the improvement in degree of lameness following surgical repair of cranial cruciate ligament rupture in dogs using computer-assisted gait analysis.

Methods: Two groups of 14 dogs were used. One group was treated by a capsular-fascial imbrication method, and the other group by tibial plateau levelling osteotomy (TPLO). All dogs underwent gait analysis prior to surgery, as well as at four days, four weeks, and four months after surgery. Symmetry indices of vertical ground reaction forces as well as vertical ground reaction forces in % body weight, joint angles and certain gait cycle parameters were evaluated.

Results: Four months after surgery, the degree of lameness expressed as symmetry index for peak vertical force for the TPLO group (5.83%) was not significantly different to the capsular-fascial imbrication group (19.05%). Within the TPLO group, there was a significantly increased ability to extend the stifle joint four months after surgery. The stifle motion pattern of the capsular-fascial imbrication group as well as the range-of-motion in both groups showed very little change at the time of the last gait analysis. The complication rate was greater in the TPLO group than in the capsular-fascial group.

Clinical significance: In conclusion the results suggest that the TPLO method leads to a faster recovery and improved limb function in comparison to the capsular-fascial imbrication method four months after surgery. Further analyses are needed to determine if the TPLO method is superior concerning long-term joint stability.

Online supplementary material: A video of the three-dimensional kinematic model is available online at: http://www.vcot-online.com

Retrospective study of 476 tibial plateau levelling osteotomy procedures

Objective: To determine the rate of subsequent ‘pivot shift’, meniscal tear and risk factors associated with complications of tibial plateau levelling osteotomy (TPLO) and to assess clinical and owner perception outcome.

Study design: Retrospective study.

Sample population: Three hundred and forty-eight dogs that had undergone TPLO surgical procedures (n = 476 stifles).

Methods: Medical records were reviewed for the retrieval of information on breed, sex, age, body weight, clinical history, radiograph findings, pre- and postoperative tibial plateau angle, limb alignment, unilateral versus bilateral disease, condition of cranial cruciate ligament (CCL) and menisci, implant material, healing time and complications. Clinical and owner-assessed questionnaire outcomes were also recorded.

Results: Forty-six (9.7%) postoperative complications were reported. Twenty (4.2%) were classified as major complications requiring an additional surgical intervention, and 26 (5.5%) as minor complications. No risk factors associated with postoperative complications were identified. Ten (2.1%) subsequent meniscal injuries in the stifles with normal unaltered menisci at time of TPLO were reported with a median postoperative time of 9.5 months. Signs of postoperative ‘pivot shift’ were reported in 15 (3.1%) stifles. All stifles with a ‘pivot shift’ had a complete CCL rupture or a debrided partial CCL rupture a medial menisectomy was identified as a risk factor for a ‘pivot shift’ (p = 0.02). Dogs with intact medial meniscus had a significantly higher activity level (p <0.0001) and a shorter time to peak function (p = 0.02) than dogs that underwent menisectomy according to an owner questionnaire.

Conclusions: Dogs with TPLO and intact meniscus seemed to have a better and faster recovery than dogs with TPLO and menisectomy based on owner questionnaires. ‘Pivot shift’ was infrequent after TPLO surgery. All dogs with a ‘pivot shift’ had a complete CCL rupture or a debrided partial CCL rupture and menisectomy was identified as a risk factor for its occurrence.

Clinical relevance: Considering the relatively low rate of subsequent meniscal injury after TPLO, systematic medial meniscal release with TPLO may be unnecessary. The ‘pivot shift’ deserved further investigation to completely understand its mechanism, to identify its anatomic components and potential consequences on the stifle joint.

Systematic review of the prevalence, risk factors, diagnosis and management of meniscal injury in dogs: Part 1. [corrected]

OBJECTIVE

To systematically evaluate the evidence reporting the frequency and risk factors of meniscal injury in dogs with cranial cruciate ligament failure.

STUDY DESIGN

Systematic literature review.

MATERIALS AND METHODS

Research questions were defined. An electronic database search of PubMed and CAB Abstracts was performed during November 2013. Data were extracted for study participants, design, intervention, outcome measures and results. Studies were evaluated using a validated instrument for assessing methodological quality and assigned a quality index score. A level of evidence was then assigned to each study.

RESULTS

Sixty-two studies were identified. The median quality index score was 14 out of a possible 26. Twenty-four studies were prospective case series, 37 retrospective case series and 1 animal research study. There were no class I or class II studies, 24 class III studies and 38 class IV studies.

CLINICAL SIGNIFICANCE

Despite a large number of publications the quality of evidence was generally low. No one study or combination of studies provided high quality evidence to establish the true frequency or risk factors for meniscal injury in dogs with cranial cruciate ligament failure.

Systematic review of the prevalence, risk factors, diagnosis and management of meniscal injury in dogs: Part 2

OBJECTIVE

To systematically evaluate the evidence reporting the diagnosis and management of meniscal injury in dogs with cranial cruciate ligament failure.

STUDY DESIGN

Systematic literature review.

MATERIALS AND METHODS

Research questions relating to the accuracy of diagnostic techniques for meniscal injury and the effects of meniscal treatment were defined. An electronic database search of PubMed and CAB Abstracts was performed during March 2015. Data were extracted for study participants, design, intervention, outcome measures and results. Studies were evaluated using a validated instrument for assessing methodological quality and assigned a Quality Index score. A level of evidence was then assigned to each study.

RESULTS

Eighty-nine studies were identified. The median Quality Index score was 14 out of a possible 26. Twenty-seven studies were prospective case series, 31 retrospective case series, 16 animal research and 15 cadaveric studies. There were no class I or class II studies, 27 class III and 62 class IV studies.

CONCLUSIONS

Despite a large number of publications the quality of evidence was generally low. No one study or combination of studies provided high quality evidence to support one diagnostic or surgical intervention over another for meniscal injuries in dogs with cranial cruciate ligament failure.

Clinical audit for the tibial tuberosity advancement procedure: establishing the learning curve and monitoring ongoing performance for the tibial tuberosity advancement procedure using the cumulative summation technique

OBJECTIVES

To quantitatively assess the learning curve for the tibial tuberosity advancement (TTA) procedure performed by a single surgeon using the cumulative summation (CUSUM) technique and to determine if surgeon performance remained under control (i.e. within specified quality boundaries) after the learning curve had been climbed.

STUDY DESIGN

Retrospective study.

ANIMALS

Dogs (n = 122) with cranial cruciate ligament deficient stifles (n = 167).

METHODS

Records of all dogs that had a TTA procedure performed by the same surgeon were reviewed. Cases were included if the following information was available: weight, breed, date of surgery, presence of partial or full cruciate rupture, meniscal pathology, occurrence and description of postoperative complications and treatment with a minimum of 12 months follow-up. Patients were excluded if they had a concurrent illness. Major complications were defined as those requiring revision surgery. The CUSUM technique was used to determine the time taken for the surgeon to reach a pre-defined level of competency and to monitor ongoing performance.

RESULTS

Major complications occurred in 15 out of 167 procedures (9%) within 12 months of TTA surgery. The complication rate decreased as surgical experience was gained with the technique, however the learning curve continued until the 22nd procedure. Thereafter, despite the target complication rate being re-set at a lower level, the surgeon's performance remained acceptable, i.e. within the revised quality boundary.

CLINICAL SIGNIFICANCE

The CUSUM technique was used for clinical audit, to determine the learning curve for the TTA procedure for a single surgeon, and to monitor ongoing performance. An experienced general practitioner had a learning curve of 22 procedures and complication rates were within the published ranges.

Reducing susceptibility artefacts in magnetic resonance images of the canine stifle following surgery for cranial cruciate ligament deficiency

BACKGROUND

Magnetic resonance (MR) images of the postoperative canine stifle are adversely affected by susceptibility artefacts associated with metallic implants.

OBJECTIVES

To determine empirically to what extent susceptibility artefacts could be reduced by modifications to MR technique.

METHODS

Three cadaveric limbs with a tibial plateau levelling osteotomy (TPLO), tibial tuberosity advancement (TTA), or extra-capsular stabilization (ECS) implant, respectively, were imaged at 1.5T. Series of proton density and T2-weighted images were acquired with different combinations of frequency-encoding gradient (FEG) direction and polarity, stifle flexion or extension, echo spacing (ES), and readout bandwidth (ROBW), and ranked. The highest rank (a rank of 1) corresponded to the smallest artefact.

RESULTS

Image ranking was affected by FEG polarity (p = 0.005), stifle flexion (p = 0.01), and ROBW (p = 0.0001). For TPLO and TTA implants, the highest ranked images were obtained with the stifle flexed, lateromedial FEG, and medial polarity for dorsal images, and craniocaudal FEG and caudal polarity for sagittal images. For the ECS implant, the highest ranked images were obtained with the stifle extended, a proximodistal FEG and proximal polarity for dorsal images, and craniocaudal FEG and cranial polarity for sagittal images.

CLINICAL SIGNIFICANCE

Susceptibility artefacts in MR images of postoperative canine stifles do not preclude clinical evaluation of joints with ECS or TTA implants.

Effects of surgical implants on high-field magnetic resonance images of the normal canine stifle

To determine the effect of surgical implants on the depiction of canine stifle anatomy in magnetic resonance (MR) images, three canine cadaver limbs were imaged at 1.5 T before and after tibial plateau leveling osteotomy (TPLO), tibial tuberosity advancement (TTA), and extra-capsular stabilization (ECS), respectively. Susceptibility artifacts associated with implants were identified in MR images as a signal void and/or signal misregistration, which obscured or distorted the anatomy. Using the preoperative images as a reference, articular structures of the stifle in postoperative images were graded using an ordinal scale to describe to what degree each anatomic structure could be evaluated for clinical purposes. The TPLO implant, which contains ferromagnetic stainless steel, produced marked susceptibility artifacts that obscured or distorted most stifle anatomy. The titanium alloy TTA implants and the stainless steel crimps used for ECS produced susceptibility artifacts that mainly affected the lateral aspect of the stifle, but allowed the cruciate ligaments and medial meniscus to be evaluated satisfactorily. Susceptibility artifact was significantly less marked in images obtained using turbo spin-echo (TSE) sequences than in sequences employing spectral fat saturation. Clinical MR imaging of canine stifles containing certain metallic implants is feasible using TSE sequences without fat saturation.

Incidence of medial meniscal tears after arthroscopic assisted tibial plateau leveling osteotomy

OBJECTIVE

To determine the incidence of medial meniscal tears in dogs with naturally occurring cranial cruciate ligament (CCL) disease treated with arthroscopy and tibial plateau leveling osteotomy (TPLO).

STUDY DESIGN

Retrospective case series.

SAMPLE POPULATION

Canine Stifles (n = 357) with naturally occurring CCL disease.

METHODS

Medical records (November 2006-November 2009) were reviewed for all dogs with CCL disease treated with arthroscopic CCL debridement, meniscal probing, and TPLO. We investigated the significance of the preoperative variables; age, weight, tibial plateau angle (TPA), sex, and the preoperative condition of the CCL on the prevalence of concurrent meniscal tears (CMT) and incidence of late onset meniscal tears (LMT).

RESULTS

Prevalence of CMT and incidence of LMT was 32.2% and 5.6%, respectively. A significant difference between age of dogs with and without CMT was identified. There was a significantly lower prevalence of CMT and incidence of LMT in dogs that had a partial CCL tear compared with those that had a complete CCL tear. All dogs with LMT treated by partial meniscectomy (PMM) returned to peak postoperative limb function after (PMM) based on client-assessed outcomes.

CONCLUSIONS

This study demonstrates the importance of LMT as a complication, the importance of comprehensive meniscal assessment, and may add to the evidence against routinely performing meniscal release in TPLO. The preoperative condition of the CCL should be considered before operating on grossly normal menisci.

Diagnostic imaging of the canine stifle: a review

The stifle joint, a common location for lameness in dogs, is a complex arrangement of osseous, articular, fibrocartilaginous, and ligamentous structures. The small size of its component structures, restricted joint space, and its intricate composition make successful diagnostic imaging a challenge. Different tissue types and their superimposition limit successful diagnostic imaging with a single modality. Most modalities exploit the complexity of tissue types found in the canine stifle joint. Improved understanding of the principles of each imaging modality and the properties of the tissues being examined will enhance successful diagnostic imaging.

Potential iatrogenic medial meniscal damage during tibial plateau leveling osteotomy

OBJECTIVE

To evaluate potential iatrogenic medial meniscal (MM) damage during tibial plateau leveling osteotomy (TPLO) and to establish a safe zone (SZ) for hypodermic needle (HN) identification of the medial aspect of the stifle joint.

STUDY DESIGN

Prospective cohort.

ANIMALS

Cadaveric canine stifles (n=40).

METHODS

HN (20 or 25 G) were inserted through the medial collateral ligament (MCL) of the femorotibial joint and through the SZ insertion points. The medial meniscus was inspected for iatrogenic damage. Statistical comparison of MM damage caused by different needle sizes and insertion sites was performed using Fisher's exact test with significance at P< .05.

RESULTS

Twenty-gauge group: 65% of stifles had minor MM damage with MCL insertion compared with 35% of stifles with SZ insertion (P=.0049). Severe MM damage occurred in 25% of stifles with MCL insertion compared with 0% of stifles with SZ insertion (P=.0014). Twenty-five-gauge group: 85% of stifles had minor MM damage with MCL insertion compared with 30% after SZ insertion (P=.0011); however, no severe MM injury was noted.

CONCLUSIONS

HN insertion though the MCL can produce iatrogenic damage to the MM. Use of a 25 G HN and SZ site for insertion reduced the frequency and severity of MM damage.

CLINICAL RELEVANCE

HN insertion into the medial aspect of the femorotibial joint during TPLO can cause gross iatrogenic MM damage, which may contribute to the incidence and misdiagnosis of latent MM injuries after TPLO.

Meniscal release in cruciate ligament intact stifles causes lameness and medial compartment cartilage pathology in dogs 12 weeks postoperatively

OBJECTIVE

To evaluate after 12 weeks the effects of caudal medial meniscal release (MR) in the cranial cruciate ligament-intact canine stifle.

STUDY DESIGN

Blinded, prospective in vivo study.

ANIMALS

Purpose-bred hound dogs (n=10).

METHODS

Either MR (n=5) or a sham (SH) surgery (n=5) was performed via arthroscopy. Orthopedic examination and subjective lameness evaluation were performed in each dog preoperatively and at 4, 8, and 12 weeks after surgery. Twelve weeks postoperatively, ultrasonographic, radiographic, and arthroscopic examinations were performed on the operated stifles. Gross pathology of the articular cartilage, cruciate ligaments, and menisci was assessed. India ink staining of the femoral and tibial articular surfaces was performed to determine the percent area of articular cartilage damage.

RESULTS

At 8 and 12 weeks after surgery, MR dogs were lamer than SH dogs. At 12 weeks, the degree of radiographic OA was significantly higher in MR stifles than in SH stifles. Gross and sonographic meniscal pathology was more severe in MR stifles compared with SH stifles. MR stifles had significantly more severe articular cartilage pathology compared with SH stifles 12 weeks after surgery; pathology was most severe in the medial compartment.

CONCLUSIONS

MR alone is associated with articular cartilage loss, further meniscal pathology, degenerative joint disease, and lameness.

CLINICAL RELEVANCE

Subsequent osteoarthritis and dysfunction of the stifle joint should be considered when making clinical decisions regarding MR in dogs.

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.

Effect of Meniscal Release on Rate of Subsequent Meniscal Tears and Owner-Assessed Outcome in Dogs with Cruciate Disease Treated with Tibial Plateau Leveling Osteotomy

OBJECTIVE

To determine and compare rates of meniscal tears after tibial plateau leveling osteotomy (TPLO) among 3 groups of dogs based on treatment method: arthrotomy with meniscal release (openR), arthrotomy without meniscal release (openNR), arthroscopy without meniscal release (scopeNR), and compare long term owner-assessed outcomes for the same groups.

STUDY DESIGN

Retrospective cohort study.

SAMPLE POPULATION

Stifles (n=254) of dogs that had TPLO.

METHODS

The three groups were compared for significant (P<.05) differences in rate of subsequent tears using a chi(2) test. Odds ratios for likelihood of subsequent meniscal tears were determined. Data for signalment, outcome, time to peak function, and time to subsequent tear were compared for significant differences using ANOVA, t-test, or rank sum test.

RESULTS

Subsequent meniscal tears were diagnosed in 16 cases (6.3%). Of dogs with subsequent meniscal tears, 9 had openNR, 4 had openR, and 3 had scopeNR; the proportion of subsequent meniscal tears was significantly different (P=.035) among groups. Odds ratio indicated that subsequent meniscal tear was 3.8 times more likely to occur for openNR than openR or scopeNR. No significant differences among groups were noted for measures of outcome.

CONCLUSIONS

Meniscal release did not reduce the rate of subsequent meniscal tears when compared with cases treated arthroscopically or when compared with all cases combined, but may be advantageous when meniscal pathology cannot be comprehensively assessed in the cranial cruciate deficient stifle. Meniscal release had no effects on owner-assessed outcome as determined in this study.

CLINICAL RELEVANCE

The low rates of subsequent meniscal tears in conjunction with the relatively high and equivocal levels of owner-assessed outcome and time to peak function for all 3 treatment groups suggest that any of these surgical management strategies can be considered acceptable. We suggest that a meniscal release be performed when complete and thorough exploration of the joint and meniscus cannot be, or are not, performed.

LOW-FIELD MRI AND ARTHROSCOPY OF MENISCAL LESIONS IN TEN DOGS WITH EXPERIMENTALLY INDUCED CRANIAL CRUCIATE LIGAMENT INSUFFICIENCY

Little is known about the magnetic resonance imaging (MRI) appearance of canine meniscal lesions. The aim of this study is to describe the MR appearance of meniscal lesions in dogs with experimentally induced cranial cruciate ligament (CCL) deficiency. The pilot study revealed dogs weighing approximately 10 kg to be too small for meniscal evaluation on low-field MRI. In the main study, dogs weighing approximately 35 kg were used. The left CCL was transected and low-field MRI was performed regularly until 13 months post-surgery. Normal menisci were defined as grade 0. Intrameniscal lesions not reaching any surface corresponded to grade 1 if focal and to grade 2 if linear or diffuse. Grade 3 lesions consisted in linear tears penetrating a meniscal surface. Grade 4 lesions included complex signal changes or meniscal distortion. Between 2 and 13 months post-surgery, all dogs developed grade 4 lesions in the medial meniscus. Most of them corresponded to longitudinal or bucket handle tears on arthroscopy and necropsy. Two dogs showed grade 3 lesions reaching the tibial surface of the lateral meniscus on MRI but not in arthroscopy. Such tears are difficult to evaluate arthroscopically; MRI provides more accurate information about the tibial meniscal surface. Grades 1 and 2 lesions could not be differentiated from presumably normal menisci with our imaging technique. An MRI grading system better adapted to canine lesions has yet to be developed. MRI is a helpful tool for the diagnosis of complete tears in the canine meniscus, especially in larger dogs.

Proximal Tibial Intraarticular Ostectomy for Treatment of Canine Cranial Cruciate Ligament Injury

OBJECTIVE

To report a technique for surgical alteration of the slope of the tibial plateau by a proximal tibial intraarticular ostectomy (PTIO) after injury to the canine cranial cruciate ligament (CCL) and to determine the outcome.

STUDY DESIGN

Prospective clinical study.

ANIMALS

Dogs (n=52) with CCL injury in 60 stifle joints.

METHODS

CCL injury was treated by lateral stifle arthrotomy, removal of CCL remnants, and appropriate meniscal surgery. PTIO was performed to remove a wedge of bone from the proximal aspect of the tibia. The ostectomy site was reduced and stabilized using a bone plate and screws applied to the medial surface of the tibia as well as a craniocaudal positional screw. Dogs were evaluated at 6 weeks, 6, and 12 months by complication assessment, lameness scores, stifle range of motion (ROM), thigh circumference, radiographic assessment, degenerative joint disease (DJD) scores, and surgeon and owner evaluation of function.

RESULTS

Lameness scores improved by 6 and 12 months in all but 1 dog. Thigh circumference and DJD were increased at 6 and 12 months. Complications occurred in 20% of dogs with all but 1 occurring perioperatively or within 6 weeks; most common were injury to the long digital extensor tendon (4 dogs) and plate failure (3); 2 other dogs required surgery to treat complications. Most owners (98%) reported that lameness had improved by 12 months; 90% were extremely or very satisfied with the procedure and 90% would have the same procedure performed on another dog.

CONCLUSION

PTIO to level the tibial plateau provided a satisfactory clinical outcome in dogs >20 kg with CCL injury and the complication rate was similar to tibial plateau levelling osteotomy (TPLO). Stifle osteoarthritis continued to progress radiographically.

CLINICAL RELEVANCE

PTIO represents an alternative to TPLO that does not require specialized surgical equipment.

Applications of Evidence-Based Medicine: Cranial Cruciate Ligament Injury Repair in the Dog

OBJECTIVE

To evaluate the literature reporting surgical interventions pertaining to canine cranial cruciate ligament (CCL) injury using an evidence-based medicine paradigm.

STUDY DESIGN

Systematic literature review.

METHODS

An on-line bibliographic search through Medline, PubMed, Veterinary Information Network, and Commonwealth Agricultural Bureau Abstracts was performed during August 2004. Two hundred and forty resources of information were identified. Studies were compared and evaluated with regard to study design (retrospective, prospective, randomization), surgical technique, short- and long-term follow-up, and evidence classification.

RESULTS

Twenty-eight resources qualified to assist with evidence classification. No class I or class II studies were present, 5 studies were categorized as a class III and 23 studies were categorized as a class IV. Seventeen studies were retrospectively designed and 11 studies were prospectively designed. Proposed results ranged from a wide variety of subjective findings including clinical impression, radiographic analysis, synovial fluid analysis, gross pathology, and histopathology. Objective results, although infrequent, included force plate analysis and cadaveric biomechanical testing.

CONCLUSIONS

At this time, the application of evidence-based medicine in analyzing the current available evidence suggests that there is not a single surgical procedure that has enough data to recommend that it can consistently return dogs to normal function after CCL injury. The requirement for assessing and categorizing the available evidence becomes increasingly important as more data becomes available and the quality of research improves.

CLINICAL RELEVANCE

An evidence-based medicine paradigm did not provide sufficient evidence favoring 1 surgical technique for management of canine CCL injury.

Effect of surgical technique on limb function after surgery for rupture of the cranial cruciate ligament in dogs

OBJECTIVE

To determine the outcome and effect of surgical technique on limb function after surgery for rupture of the cranial cruciate ligament (RCCL) and injury to the medial meniscus in Labrador Retrievers.

STUDY DESIGN

Prospective clinical study.

ANIMALS

131 Labrador Retrievers with unilateral RCCL and injury to the medial meniscus and 17 clinically normal Labrador Retrievers.

PROCEDURE

Affected dogs had partial or complete medial meniscectomy and lateral suture stabilization (LSS), intracapsular stabilization (ICS), or tibial plateau leveling osteotomy (TPLO). Limb function was measured before surgery and 2 and 6 months after surgery. Treated dogs were evaluated to determine the probability that they could be differentiated from clinically normal dogs and tested to determine the likelihood that they achieved improvement.

RESULTS

No difference was found between LSS or TPLO groups, but dogs treated with ICS had significantly lower ground reaction forces at 2 and 6 months. Compared with clinically normal dogs only, 14.9% of LSS-, 15% of ICS-, and 10.9% of TPLO-treated dogs had normal limb function. Improvement was seen in only 15% of dogs treated via ICS, 34% treated via TPLO, and 40% treated via LSS.

CONCLUSIONS AND CLINICAL RELEVANCE

Surgical technique can influence limb function after surgery. Labrador Retrievers treated via LSS, ICS, or TPLO for repair for of RCCL and medial meniscal injury managed with partial or complete meniscectomy infrequently achieve normal function. Results of LSS and TPLO are similar and superior to ICS.

Comparison of the effects of caudal pole hemi-meniscectomy and complete medial meniscectomy in the canine stifle joint

OBJECTIVE

To compare the effects of caudal pole hemi-meniscectomy (CPHM) and complete medial meniscectomy (MM), specifically with respect to development of secondary osteoarthritis, in the stifle joints of clinically normal dogs.

ANIMALS

14 large-breed dogs.

PROCEDURE

Unilateral CPHM (7 dogs) or MM (7) was performed, and the left stifle joints served as untreated control joints. Gait was assessed in all dogs before surgery and at 4, 8, 12, and 16 weeks postoperatively. After euthanasia, joints were evaluated grossly; Mankin cartilage scores, subchondral bone density assessment, and articular cartilage proteoglycan extraction and western blot analyses of 3B3(-) and 7D4 epitopes were performed.

RESULTS

Weight distribution on control limbs exceeded that of treated limbs at 4 and 16 weeks after surgery in the CPHM group and at 4 and 8 weeks after surgery in the MM group; weight distribution was not significantly different between the 2 groups. After 16 weeks, incomplete meniscal regeneration and cartilage fibrillation on the medial aspect of the tibial plateau and medial femoral condyle were detected in treated joints in both groups. Mankin cartilage scores, subchondral bone density, and immunoexpression of 3B3(-) or 7D4 in articular cartilage in CPHM- or MM-treated joints were similar; 7D4 epitope concentration in synovial fluid was significantly greater in the MM-treated joints than in CPHM-treated joints.

CONCLUSIONS AND CLINICAL RELEVANCE

Overall severity of secondary osteoarthritis induced by CPHM and MM was similar. Investigation of 7D4 epitope concentration in synovial fluid suggested that CPHM was associated with less disruption of chondrocyte metabolism.

Cranial cruciate ligament injury in the dog: pathophysiology, diagnosis and treatment

Cranial cruciate ligament (CCL) disease in the dog is a multifactorial complex problem that requires a thorough understanding of the biomechanics of the stifle joint to be understood. Successful treatment of rupture of the CCL should be based on managing underlying anatomical and conformational abnormalities rather than attempting to eliminate the tibial cranial drawer sign. The cranial and caudal cruciate ligaments, the patella ligament and quadriceps mechanism, the medial and lateral collateral ligaments, the medial and lateral menisci and the joint capsule provide stability of the joint and load-sharing. The function of the stifle is also significantly influenced by the musculature of the pelvic limb. An active model of biomechanics of the stifle has been described that incorporates not only the ligamentous structures of the stifle but also the forces created by weight-bearing and the musculature of the pelvic limb. This model recognises a force called cranial tibial thrust, which occurs during weight-bearing, and causes compression of the femoral condyles against the tibial plateau. In middle-aged, large-breed dogs, forces acting on the CCL together with conformation-related mild hyperextension of the stifle and slightly increased tibial plateau slopes are suspected to cause progressive degeneration of the ligament. Palpation of craniolateral stifle laxity has become pathognomonic for CCL rupture; however, chronic periarticular fibrosis, a partial CCL rupture, and a tense patient, may make evaluation of instability of the stifle difficult. Surgical treatment is broadly separated into three groups: intracapsular, extracapsular, and tibial osteotomy techniques. Tibial osteotomy techniques do not serve to provide stability of the stifle but rather alter the geometry of the joint to eliminate cranial tibial thrust such that functional joint stability is achieved during weight-bearing. Visualisation of both menisci is a critical aspect of CCL surgery, irrespective of the technique being performed. Regardless of the surgical technique employed, approximately 85% of dogs show clinical improvement. However, many of these dogs will demonstrate intermittent pain or lameness. Post-operative management is an integral part of the treatment of CCL rupture, and significant benefits in limb function occur when formalised post-operative physiotherapy is performed.

Surgical and postoperative complications associated with tibial plateau leveling osteotomy in dogs with cranial cruciate ligament rupture: 397 cases (1998-2001)

OBJECTIVE

To identify surgical and postoperative complications of tibial plateau leveling osteotomy (TPLO) in dogs with rupture of the cranial cruciate ligament (CCL) and compare their incidence with those reported in the literature for other commonly performed CCL stabilization procedures.

DESIGN

Retrospective study.

ANIMALS

346 dogs undergoing 397 TPLO procedures.

PROCEDURE

Medical records of dogs undergoing 563 consecutive TPLO procedures were reviewed. Complications were recorded and assigned to groups on the basis of the period during which the complication was observed.

RESULTS

397 TPLOs met the criteria for inclusion in the study. Complications (n = 136) were recorded in 113 of the 397 (28%) procedures. Multiple complications developed in 10 dogs. In 19 dogs, a second surgery was performed to manage complications. Development of a complication after surgery was not associated with age or body weight of the dog, tibial plateau angle prior to stifle joint surgery, or experience of the surgeon. Factors significantly associated with complications were breed and performance of an arthrotomy concomitantly with TPLO.

CONCLUSIONS AND CLINICAL RELEVANCE

TPLO was associated with development of numerous complications, some of which required surgical correction. Most complications resolved with nonsurgical treatment. Several complications were unique to the TPLO procedure because of the surgical technique and implants required. Although TPLO was associated with a greater number of complications than other CCL stabilization methods, the incidence of major complications was similar.

Arthroscopic evaluation of menisci in dogs with cranial cruciate ligament injuries: 100 cases (1999-2000)

OBJECTIVE

To determine prevalence of meniscal injuries by use of arthroscopic examination in dogs with cranial cruciate ligament (CCL) injuries.

DESIGN

Retrospective study.

ANIMALS

94 dogs with 100 injured CCLs.

PROCEDURE

Records for 94 large dogs (> 20 kg [44 lb]) with 100 naturally occurring CCL injuries that were examined arthroscopically were reviewed. Pathologic findings in the CCL (complete or partial tears), prevalence and type of meniscal injuries, and periarticular osteophytes were recorded.

RESULTS

77% of joints had tears of the lateral meniscus; most were a series of small radial tears of the cranial horn. Fifty-eight percent of joints had tears of the medial meniscus. Positive correlation between complete tears of the CCL and medial meniscal damage was found. No significant relationships were detected between periarticular osteophyte formation and meniscal injury, medial and lateral meniscal injury, or degree of CCL tear and lateral meniscal injury.

CONCLUSIONS AND CLINICAL RELEVANCE

There is a strong association between CCL injury and lateral and medial meniscal injuries in dogs. Clinical importance of lateral meniscal lesions is not known; a much higher percentage of dogs had such injuries than has been reported previously, possibly because of use of arthroscopy.

Cartilage-derived biomarkers of osteoarthritis in synovial fluid of dogs with naturally acquired rupture of the cranial cruciate ligament

OBJECTIVE

To compare synovial fluid biomarkers of cartilage metabolism in joints with naturally acquired or experimentally induced cranial cruciate ligament (CCL) rupture and determine correlations with stage and severity of disease in dogs.

ANIMALS

95 dogs with ruptured CCL, 8 dogs with experimentally ruptured CCL, and 24 healthy dogs.

PROCEDURES

Synovial fluid was assayed for chondroitin sulfate neo-epitopes 3B3(-) and 7D4 and glycosaminoglycan (GAG) concentration. Results were correlated with demographic data, duration of lameness, radiographic osteoarthritis score, and intra-articular lesions.

RESULTS

The 7D4 concentrations and 7D4:GAG in synovial fluid from joints with naturally acquired CCL rupture and experimental CCL transection were similar and significantly greater than values for healthy control joints. The 3B3(-) concentrations in the CCL-deficient groups were not significantly different, although only values in the naturally acquired CCL rupture group were significantly greater than those in the healthy control group. Within the naturally acquired CCL rupture group there was a significant correlation between 3B3(-) and 7D4 concentrations. However, there were no significant correlations between biomarker concentrations and continuous demographic or disease-related variables or differences in biomarker concentrations with different categories of disease.

CONCLUSIONS AND CLINICAL RELEVANCE

Synovial fluid biomarker concentrations were significantly increased in joints with secondary osteoarthritis associated with naturally acquired or experimental CCL rupture; however, lack of apparently simple relationships with demographic variables or stage or severity of disease limits their clinical usefulness.

Effects of postoperative rehabilitation on limb function after cranial cruciate ligament repair in dogs

OBJECTIVE

To determine the effects of early postoperative rehabilitation on limb function in dogs after surgery for ruptured cranial cruciate ligament (RCCL).

DESIGN

Prospective clinical study.

ANIMALS

51 client-owned dogs.

PROCEDURE

Dogs weighing between 20 and 40 kg (44 to 88 lb) that had RCCL and medial meniscal injury were studied. After removal of the RCCL and complete medial meniscectomy, the stifle joint was stabilized by use of a lateral retinacular stabilization technique. Twenty-five dogs were included in a postoperative rehabilitation group, and 26 dogs were included in an exercise-restricted group. Limb function (peak vertical force [PVF] and vertical impulse [VI]) was determined before surgery and 6 months after surgery, using force platform gait analysis.

RESULTS

Prior to surgery, mean PVF and VI in affected limbs were similar between groups. Six months after surgery, PVF and VI were significantly increased in dogs of both groups. However, PVF and VI in dogs in the rehabilitation group were significantly greater than those of dogs in the exercise-restricted group. At this time, differences in limb function (as measured by PVF and VI) between the repaired and normal limbs were not evident in dogs in the rehabilitation group. Conversely, limb function in the repaired limb of dogs in the exercise-restricted group was still significantly less than that of the normal limb.

CONCLUSION AND CLINICAL RELEVANCE

Dogs that have surgery for RCCL and a torn medial meniscus benefit from postoperative rehabilitation; rehabilitation should be considered part of the postoperative management of these patients.

Kinetic study of the replacement of porcine small intestinal submucosa grafts and the regeneration of meniscal-like tissue in large avascular meniscal defects in dogs

Porcine small intestinal submucosa (SIS) was used to replace large, avascular defects in the medial menisci of dogs. Twelve dogs received SIS grafts and 3 dogs were left untreated as controls. Dogs were evaluated at 4, 8, and 12 weeks by means of lameness scoring and ultrasonography. Dogs were sacrificed at 1, 6, or 12 weeks after implantation, and the tissue at the site of meniscal resection was evaluated for gross and histologic appearance, cross-sectional and surface area, and collagen types I and II. The femoral and tibial condyles were assessed for articular cartilage damage. Control dogs were significantly more lame than grafted dogs 8 and 12 weeks after instrumentation. Grafted dogs' replacement tissue appeared meniscal-like when evaluated grossly and ultrasonographically 12 weeks after instrumentation. The amount of replacement tissue was significantly greater in both cross-sectional and surface area for grafted dogs than for controls at all time points. Histologically, the SIS biomaterial could be identified in all grafted dogs at 1 week post-implantation, but in none at 6 weeks post-implantation. Subjectively, grafted dogs' replacement tissue was histologically superior to that of controls with respect to tissue type, organization, and architecture. Collagen types I and II immunoreactivity in grafted menisci were similar to that of normal menisci. Control dogs had significantly more articular cartilage damage than grafted dogs. SIS appears to induce regeneration of meniscal-like tissue in large, avascular meniscal defects in dogs, resulting in superior clinical function and articular cartilage protection compared to ungrafted controls.

Pathologic changes in grossly normal menisci in dogs with rupture of the cranial cruciate ligament

OBJECTIVE

To determine whether histopathologic changes are detectable in grossly normal medial menisci from dogs with rupture of the cranial cruciate ligament (CCL).

DESIGN

Case series.

SAMPLE POPULATION

40 medial menisci from dogs with rupture of the CCL and 20 medial menisci from control dogs without stifle joint disease.

PROCEDURE

Data evaluated included age, duration of clinical signs, and whether rupture of the CCL was complete or incomplete. Three groups (n = 20/group) were also compared on the basis of 5 histologic criteria; group-1 menisci appeared grossly normal and were obtained from dogs with naturally occurring rupture of the CCL, group-2 menisci were grossly abnormal and were also obtained from dogs with naturally occurring CCL ruptures, and group-3 menisci were collected at postmortem from dogs without stifle joint disease that were of similar age and weight as dogs in groups 1 and 2.

RESULTS

Group-2 menisci were significantly different from group-1 and -3 menisci in all histologic criteria. Group-1 menisci were significantly different from control menisci in only 1 of the 5 histologic criteria (cartilage differentiation). Dogs that were > or =3 years old had significantly more surface cellularity than did dogs that were < 3 years old. A significant difference was not detected between groups 1 and 2 with regard to completeness of rupture.

CONCLUSIONS AND CLINICAL RELEVANCE

Histologic changes in meniscal cartilage correlate with gross appearance of the cartilage at time of surgery for rupture of the CCL. On the basis of minimal histologic changes, routine removal of grossly normal menisci does not appear to be warranted.

Concentrations of chondroitin sulfate epitopes 3B3 and 7D4 in synovial fluid after intra-articular and extracapsular reconstruction of the cranial cruciate ligament in dogs

OBJECTIVE

To evaluate effects of intra-articular and extracapsular reconstruction of the cranial cruciate ligament (CCL) on metabolism of articular cartilage as reflected by concentrations of chondroitin sulfate epitopes 3B3 and 7D4 in synovial fluid.

ANIMALS

13 adult dogs.

PROCEDURE

Each dog underwent unilateral CCL transection (CCLT). One month after CCLT, sham CCL reconstruction (3 dogs), intra-articular CCL reconstruction (5), or extracapsular CCL reconstruction (5) was performed. Synovial fluid was collected by direct arthrocentesis from CCLT and contralateral stifle joints immediately before (time 0) and 1, 3, and 5 months after CCLT. Fluid was examined for concentrations of 3B3 and 7D4 epitopes and total sulfated glycosaminoglycan (GAG) content.

RESULTS

Concentrations of 3B3, 7D4, and GAG, 3B3:GAG, or 7D4:GAG in CCLT joints did not differ significantly among treatment groups nor in the ratios of these variables in CCLT joints to contralateral joints at 3 months. In a longitudinal analysis, concentrations of 3B3 and 7D4, 3B3:GAG, and 7D4:GAG in CCLT joints in all groups changed significantly with time, but we did not detect time X group interactions.

CONCLUSIONS AND CLINICAL RELEVANCE

Transection of CCL resulted in significant perturbation in articular cartilage metabolism as reflected by alterations in concentrations of 3B3 and 7D4 in synovial fluid. These changes over time were not significantly influenced by method of CCL reconstruction. We did not find evidence that surgical stabilization of CCL-deficient joints by intra-articular or extracapsular techniques had any effect on preventing alterations in composition of synovial fluid that have been associated with secondary osteoarthritis.

Induction of meniscal regeneration in dogs using a novel biomaterial

A unique biomaterial, porcine small intestinal submucosa, was used to construct grafts for implantation into surgically created medial meniscal defects in dogs. Five dogs received grafts and two were left untreated as controls. All dogs were evaluated at 4, 8, and 12 weeks by means of lameness scoring, force plate analysis, and ultrasonography. Twelve weeks after implantation the dogs were sacrificed and the replacement tissue was evaluated for gross and histologic appearance, amount, glycosaminoglycan content, and type II collagen immunoreactivity. Four weeks after instrumentation, both groups had lameness scores that were significantly higher than preoperative scores, but at the 8- and 12-week evaluations, scores for the grafted dogs were not different from preoperative values. The ultrasonographic appearance of replacement tissue in grafted defects resembled normal meniscus. In the untreated defects, only unorganized tissue was present. In control dogs, replacement tissue resembled fibrous tissue and cartilage erosions were visible on the medial femoral condyles. In four of the five grafted dogs, replacement tissue was grossly indistinguishable from normal meniscus. The amount of tissue in the defect was significantly greater for the grafted dogs. Histologically, replacement tissue in control dogs was composed of vascularized connective tissue with no evidence of chondroid differentiation. Replacement tissue in grafted dogs closely resembled normal meniscal tissue with respect to chondroid differentiation, collagen content, and zonal architecture. Porcine small intestinal submucosa appeared to have beneficial effects on meniscal regeneration.

Clinical natural history of the postsurgical cruciate deficient canine stifle joint: year 1

The aims of this prospective study were to investigate the associations and correlations between individual clinical features of osteoarthritis of the cruciate deficient stifle joint and to document the temporal changes in these features over a 13-month period following surgical treatment. Fifty-eight dogs with osteoarthritis of the stifle joint, secondary to cranial cruciate ligament deficiency, were examined before surgical treatment for cruciate deficiency and at one and a half, seven and 13 months after surgery. At each visit, clinical features were graded using four-point, discontinuous, ordinal grading (Likert) scales and intra-articular pathology was also scored in a similar fashion at arthrotomy. No attempt was made to construct an aggregate score because the relative importance of different disease features and the relationships between them were not understood at the time of writing. At entry, the relationships between background disease variables and clinical parameters were investigated as well as the relationships between clinical parameters and intra-articular pathology scores. Longitudinal analysis was performed to test for those features which showed significant change over the 13-month follow-up period. At entry, periarticular thickening and degree of crepitus were significantly correlated with disease duration. Several features showed significant change over the study period. Notably, the degree of quadriceps atrophy showed significant decrease from baseline scores at seven and 13 months while remaining different from normal, suggesting that a measure of quadriceps atrophy may be a useful measure of long-term outcome in this disease.