Complications associated with closing wedge ostectomy procedure for treatment of cranial cruciate ligament rupture in dogs : a retrospective study of 145 cases

Dissertação de Mestrado Integrado em Medicina Veterinária

Le rôle de la leptine dans le métabolisme anormal des ostéoblastes de patients atteints d’ostéoarthrose

L’ostéoarthrose (OA) est une pathologie qui touche les articulations principalement chez les personnes âgées. Il devient capital de mieux cerner cette pathologie à cause des coûts économiques qu’elle engendre mais surtout à cause du vieillissement de la population. Cette maladie se caractérise par une dégradation du cartilage articulaire, une sclérose osseuse, une inflammation de la membrane synoviale ainsi que la présence d’ostéophytes. L’étiologie de cette pathologie est restée nébuleuse car la recherche sur la maladie touchait principalement le cartilage articulaire. Toutefois, le rôle clé de l’os sous-chondral dans l’OA est maintenant reconnu. L’obésité étant un facteur de risque de l’OA, nous avons émis l’hypothèse que la leptine, une adipocytokine clé dans l’obésité, joue un rôle important dans l’OA. En effet, la leptine modifie le phénotype des ostéoblastes (Ob) normaux humain et puisque les Ob OA humains ont un phénotype altéré, notre objectif était de déterminer le rôle potentiel de la leptine dans ces cellules. Pour ce faire, nous avons préparé des cultures primaires d’Ob issus de la plaque sous-chondral du plateau tibial de patients OA et d’individus normaux (N). L’expression de la leptine et de son récepteur actif (OB-Rb) ont été mesurées par RT-PCR en temps réel, et leur production a été mesurée par ELISA et immunobuvardage (IB). La prolifération des Ob OA a été déterminée par incorporation de BrdU. La phosphorylation de p42/44 MAPK dans les Ob OA a été déterminée par IB. Le phénotype des Ob fut déterminé par la mesure de l’activité de la phosphatase alcaline (ALP) et la sécrétion d’ostéocalcine (OC), en présence ou non de leptine. De plus, les effets des ARNs d’interférences (SiRNA) anti-leptine et anti OB-Rb sur le phénotype des Ob OA furent déterminés via leur impact sur l’activité de l’ALP et sur la sécrétion d’OC. L’effet dose-réponse de la leptine sur les expressions d’OB-Rb, du facteur de croissance TGF-1 ou encore sur sa propre expression furent déterminées par RT-PCR en temps réel. Pour terminer, la signalisation de la leptine a été étudiée en évaluant l’effet dose réponse de celle-ci sur la production des protéines JAK2 et STAT3 phosphorylées par IB. Les résultats obtenus ont montrés que les Ob OA expriment et produisent plus de leptine que les Ob N. Au niveau phénotypique, ces Ob OA possèdent une activité de l’ALP ainsi qu’une sécrétion d’OC plus importante que celles observées chez les Ob N. L’ajout d’anticorps inactivant l’interaction leptine et OB-Rb ou d’inhibiteurs chimiques comme tyrphostin ou piceatannol diminuèrent l’activité de l’ALP ainsi que la sécrétion d’OC dans les Ob OA. Par contre, l’ajout de leptine exogène aux Ob OA augmenta l’activité de l’ALP sans pour autant faire varier la sécrétion d’OC. La leptine à des doses de 1ng/ml à 10mg/ml stimula la prolifération des Ob OA ainsi que la phosphorylation de p42/44 MAPK. La leptine exogène diminua l’expression de TFG-1 tandis qu’elle stimula la phosphorylation de JAK2 et STAT3 ou encore sa propre expression de manière dose-dépendante. Cependant, l’expression d’OB-Rb diminua de manière dose-dépendante. Enfin, le traitement des Ob OA avec des Si leptine ou Si OB-Rb diminua l’activité d’ALP, la sécrétion d’OC, l’expression de la leptine, l’expression d’OB-RB ainsi que l’expression du facteur TGF-1. L’ensemble de ces données démontre que la leptine endogène des Ob OA est sous contrôle des facteurs de croissance et qu’elle contribue à maintenir le phénotype anormal de l’os sous-chondral OA. De plus, ceci suggère que la leptine serait un acteur important dans la régulation du remodelage osseux.

Imaging of knee injuries with special focus on tibial plateau fractures

Acute knee injury is a common event throughout life, and it is usually the result of a traffic accident, simple fall, or twisting injury. Over 90% of patients with acute knee injury undergo radiography. An overlooked fracture or delayed diagnosis can lead to poor patient outcome. The major aim of this thesis was retrospectively to study imaging of knee injury with a special focus on tibial plateau fractures in patients referred to a level-one trauma center. Multi-detector computed tomography (MDCT) findings of acute knee trauma were studied and compared to radiography, as well as whether non-contrast MDCT can detect cruciate ligaments with reasonable accuracy. The prevalence, type, and location of meniscal injuries in magnetic resonance imaging (MRI) were evaluated, particularly in order to assess the prevalence of unstable meniscal tears in acute knee trauma with tibial plateau fractures. The possibility to analyze with conventional MRI the signal appearance of menisci repaired with bioabsorbable arrows was also studied. The postoperative use of MDCT was studied in surgically treated tibial plateau fractures: to establish the frequency and indications of MDCT and to assess the common findings and their clinical impact in a level-one trauma hospital. This thesis focused on MDCT and MRI of knee injuries, and radiographs were analyzed when applica-ble. Radiography constitutes the basis for imaging acute knee injury, but MDCT can yield information beyond the capabilities of radiography. Especially in severely injured patients , sufficient radiographs are often difficult to obtain, and in those patients, radiography is unreliable to rule out fractures. MDCT detected intact cruciate ligaments with good specificity, accuracy, and negative predictive value, but the assessment of torn ligaments was unreliable. A total of 36% (14/39) patients with tibial plateau fracture had an unstable meniscal tear in MRI. When a meniscal tear is properly detected preoperatively, treatment can be combined with primary fracture fixation, thus avoiding another operation. The number of meniscal contusions was high. Awareness of the imaging features of this meniscal abnormality can help radiologists increase specificity by avoiding false-positive findings in meniscal tears. Postoperative menisci treated with bioabsorbable arrows showed no difference, among different signal intensities in MRI, among menisci between patients with operated or intact ACL. The highest incidence of menisci with an increased signal intensity extending to the meniscal surface was in patients whose surgery was within the previous 18 months. The results may indicate that a rather long time is necessary for menisci to heal completely after arrow repair. Whether the menisci with an increased signal intensity extending to the meniscal surface represent improper healing or re-tear, or whether this is just the earlier healing feature in the natural process remains unclear, and further prospective studies are needed to clarify this. Postoperative use of MDCT in tibial plateau fractures was rather infrequent even in this large trauma center, but when performed, it revealed clinically significant information, thus benefitting patients in regard to treatment.

Percutaneous cement augmentation for the treatment of depression fractures of the tibial plateau

The management of insufficiency fractures of the tibial plateau in osteoporotic patients can be very challenging, since it is difficult to achieve a stable fixation, an essential condition for the patients' early mobilization. We present a minimally invasive technique for the treatment of proximal tibial plateau fractures, "tibiaplasty", using percutaneous polymethylmethacrylate augmentation. Five osteoporotic patients (7 fractures) with a non-traumatic insufficiency tibial plateau fracture were treated with this technique at the authors' institution from 2006 to 2008. The patients' median age was 79 (range 62-88) years. The intervention was performed percutaneously under general or spinal anesthesia; after the intervention, immediate full weight bearing was allowed. The technique was feasible in all patients and no complications related to the intervention were observed. All patients reported a relevant reduction in pain, were able to mobilize with full weight bearing and would undergo the operation again. No secondary loss of reduction or progression of arthrosis was observed in radiological controls; no revision surgery was required. Our initial results indicate that tibiaplasty is a good treatment option for the management of insufficiency in tibial plateau fractures in osteoporotic patients. The technique is minimally invasive, safe and allows immediate mobilization without restrictions. In our group of patients, we found excellent early to mid-term results.

Stereologic analysis of tibial-plateau cartilage and femoral cancellous bone in guinea pigs with spontaneous osteoarthritis

Two strains of guinea pig develop spontaneous osteoarthritis of the knee. Although the disease evolves at different rates in the two strains, it is not known whether these differences are reflected in the structure of the cartilage and cancellous bone.

Unstable bicondylar tibial plateau fractures: a clinical investigation

OBJECTIVE: To evaluate fracture patterns in bicondylar tibial plateau fractures and their impact on treatment strategy. DESIGN: Prospective data analysis with documentation of initial injury and treatment strategy, computed tomography scans, conventional x-rays, long-term evaluation of radiographs, and functional assessments. SETTING: Level 1 regional trauma center. PATIENTS: Prospective data acquisition of 14 consecutive patients (10 male and 4 female) with a bicondylar tibial plateau fracture (AO Type C). INTERVENTION: Application of a stepwise reconstruction strategy of the tibial plateau starting with the reposition and fixation of the posteromedial split fragment using a 3.5 buttress plate, followed by reposition and grafting of the lateral compartment and lateral fixation with a 3.5 plate in 90 degree to the medial fixation device. MAIN OUTCOME MEASUREMENTS: All patients were evaluated with full-length standing film, standardized x-rays, Lysholm score for functional assessment, and patient's self-appraisal. RESULTS: Most of the complex bicondylar fractures follow a regular pattern in that the medial compartment is split in a mediolateral direction with a posteromedial main fragment, combined with various amounts of multifragmental lateral compartment depression. The technique introduced allows for accurate and stable reduction and fixation of this fracture type. The final Lysholm knee score showed an average of 83.5 points (range: 64.5-92). CONCLUSIONS: Complex bicondylar tibial plateau fractures follow a regular pattern, which is not represented in existing 2-dimensional fracture classifications. A 2-incision technique starting with the reduction of the posteromedial edge results in accurate fracture reduction with low complication rates and excellent knee function.

The mean anatomical shape of the tibial plateau at the knee arthroplasty resection level: an investigation using MRI

Clinical assessments after Total Knee Arthroplasty (TKA) show persisting pain after implantation in over 20% of patients. Impingement of soft tissue around the knee, due to imprecise geometry of the tibial implant, can be one reason for persisting ailment. Two hundred and thirty seven MRI scans were evaluated using an active contour detection algorithm (snake) to obtain a high-resolution mean anatomical shape of the tibial plateau. Differences between female and male, older and younger (40) and left and right averaged shapes were determined. The shapes obtained were asymmetric throughout. Absolute differences between the subgroups fell short of inter-individual variations represented by calculated one-sigma confidence intervals. Our results indicate that a differentiation in TKA tibial plateau design by gender, age, or side is of minor relevance.

Evaluation of peri-operative epidural analgesia with ropivacaine, ropivacaine and sufentanil, and ropivacaine, sufentanil and epinephrine in isoflurane anesthetized dogs undergoing tibial plateau levelling osteotomy

The purpose of this study was to compare four epidural protocols for peri-operative analgesia in dogs undergoing tibial plateau levelling osteotomy. Forty client-owned dogs were randomly assigned to one of four treatments - groups R0.5 and R1 received 0.5mg/kg and 1mg/kg ropivacaine, respectively. Group SR0.5 received 1mug/kg sufentanil plus 0.5mg/kg ropivacaine, and group SER0.5 received 1mug/kg sufentanil, 0.5mg/kg ropivacaine plus 6mug/kg epinephrine. Dilution, when required, was performed with saline, so that the injected volume was always 0.2mL/kg. Intra-operatively, nociception assessment was based on the evaluation of changes in heart rate, respiratory rate and mean arterial pressure. Post-operative pain assessment was performed using the Glasgow visual analogue pain scale, and an ad hoc multifactorial pain score. Motor block was evaluated using a modified Bromage score. Intra-operatively, none of the animals was hypotensive. All groups except SER0.5 required rescue intra-operative fentanyl (40%, 30% and 40% of the animals in groups R0.5, R1 and SR0.5, respectively). Group SER0.5 showed lower post-operative pain scores, and group R1 significantly greater motor block, compared to the other treatment groups. None of the dogs had urinary retention. Epidural sufentanil-epinephrine-ropivacaine provided superior peri-operative analgesia compared to the other treatments, without producing clinically relevant side effects.

Preemptive carprofen for peri-operative analgesia in dogs undergoing Tibial Plateau Leveling Osteotomy (TPLO): a prospective, randomized, blinded, placebo controlled clinical trial

Eighteen client-owned dogs undergoing Tibial Plateau Leveling Osteotomy (TPLO) were included in this blinded clinical study and randomly assigned to one of two treatment groups. Group C (carprofen) received intravenous (IV) carprofen, 4 mg/kg, prior to anesthesia, whereas group P (placebo) received IV saline. General anesthesia was maintained with isoflurane in oxygen and a constant rate infusion (CRI) of sufentanyl IV. Intra-operatively, assessment of nociception was based on changes in physiological parameters and on the analgesics requirement, whereas in the post-operative period evaluation of pain was performed by using a Hellyer and Gaynor pain score and by comparing the doses of rescue buprenorphine required by the two treatment groups. Although no statistically significant differences in intra-operative sufentanyl doses were found between treatment groups, group C had superior cardiovascular stability, and lower post-operative pain scores and rescue buprenorphine doses than group P. Our results indicate that administration of carprofen prior to surgery was effective in improving peri-operative analgesia in dogs undergoing TPLO.

Tibial Plateau angles with and without cranial cruciate ligament rupture: comparison between different dog populations and a wolf population.

The tibial plateau angles (TPA) of dogs with and without cranial cruciate ligament (CrCL) injuries were evaluated and further compared to the TPAs of dogs from a previous population and of wolves. Similar TPA measurements were found in all groups, suggesting that any possible changes in breeding practises, breed preferences, nutrition or other factors have not significantly influenced the TPA over time. Moreover, a difference was not found in the TPA between any group and the group affected with CrCL injury, suggesting that the TPA is not a clinically relevant predisposing factor in the development of canine CrCL rupture.

Addition of magnesium sulphate to ropivacaine for spinal analgesia in dogs undergoing tibial plateau levelling osteotomy

The aim of this blinded, randomised, prospective clinical trial was to determine whether the addition of magnesium sulphate to spinally-administered ropivacaine would improve peri-operative analgesia without impairing motor function in dogs undergoing orthopaedic surgery. Twenty client-owned dogs undergoing tibial plateau levelling osteotomy were randomly assigned to one of two treatment groups: group C (control, receiving hyperbaric ropivacaine by the spinal route) or group M (magnesium, receiving a hyperbaric combination of magnesium sulphate and ropivacaine by the spinal route). During surgery, changes in physiological variables above baseline were used to evaluate nociception. Arterial blood was collected before and after spinal injection, at four time points, to monitor plasma magnesium concentrations. Post-operatively, pain was assessed with a modified Sammarco pain score, a Glasgow pain scale and a visual analogue scale, while motor function was evaluated with a modified Tarlov scale. Assessments were performed at recovery and 1, 2 and 3 h thereafter. Fentanyl and buprenorphine were administered as rescue analgesics in the intra- and post-operative periods, respectively. Plasma magnesium concentrations did not increase after spinal injection compared to baseline. Group M required less intra-operative fentanyl, had lower Glasgow pain scores and experienced analgesia of longer duration than group C (527.0 ± 341.0 min vs. 176.0 ± 109.0 min). However, in group M the motor block was significantly longer, which limits the usefulness of magnesium for spinal analgesia at the investigated dose. Further research is needed to determine a clinically effective dose with shorter duration of motor block for magnesium used as an additive to spinal analgesic agents.

Use of a perineural coiled catheter at the sciatic nerve in dogs after tibial plateau levelling osteotomy – preliminary observations

The analgesic effects of peripheral nerve blocks can be prolonged with the placement of perineural catheters allowing repeated injections of local anaesthetics in humans. The objectives of this study were to evaluate the clinical suitability of a perineural coiled catheter (PCC) at the sciatic nerve and to evaluate pain during the early post-operative period in dogs after tibial plateau levelling osteotomy. Pre-operatively, a combined block of the sciatic and the femoral nerves was performed under sonographic guidance (ropivacaine 0.5%; 0.3 mL kg−1 per nerve). Thereafter, a PCC was placed near the sciatic nerve. Carprofen (4 mg kg−1 intravenously) was administered at the end of anaesthesia. After surgery, all dogs were randomly assigned to receive four injections of ropivacaine (group R; 0.25%, 0.3 mL kg−1) or NaCl 0.9% (group C; 0.3 mL kg−1) every 6 h through the PCC. Pain was assessed by use of a visual analogue scale (VAS) and a multi-dimensional pain score (4Avet) before surgery (T-1), for 390 min (T0, T30, T60, T120, T180, T240, T300, T360 and T390) as well as 1 day after surgery (Day 1). Methadone (0.1 mg kg−1) was administered each time the VAS was ≥40 mm or the 4Avet was ≥5. At T390 dogs received buprenorphine (0.02 mg kg−1). Data were compared using Mann–Whitney rank sum tests and repeated measures analysis of variance. Regardless of group allocation, 55% of dogs required methadone. VAS was significantly lower at T390 (P = 0.003), and at Day 1 (P = 0.002) and so was 4Avet at Day 1 (P = 0.012) in group R than in group C. Bleeding occurred in one dog at PCC placement and PCC dislodged six times of 47 PCCs placed. Minor complications occurred with PCC but allowed four repeated administrations of ropivacaine or saline over 24 h in 91.5% of the cases.

Effects of early intensive postoperative physiotherapy on limb function after tibial plateau leveling osteotomy in dogs with deficiency of the cranial cruciate ligament

Objective-To determine effects of early intensive postoperative physiotherapy on limb function in dogs after tibial plateau leveling osteotomy (TPLO) for deficiency of the cranial cruciate ligament (CCL). Animals-8 adult dogs with CCL deficiency. Procedure-After TPLO, dogs underwent a physiotherapy program 3 times/wk (physiotherapy group; n = 4) or a walking program (home-exercise group; 4). All dogs were evaluated before surgery, 1 and 10 days after surgery, and 3 and 6 weeks after surgery. Thigh circumference (TC), stifle joint flexion and extension range of motion (ROM), lameness, and weight-bearing scores were recorded. Results-Before surgery, CCL-deficient limbs had significantly reduced TC and reduced flexion and extension ROMs, compared with values for the contralateral control limb. Six weeks after TPLO, the physiotherapy group had significantly larger TC than the home-exercise group, with the difference no longer evident between the affected and nonaffected limbs. Extension and flexion ROMs were significantly greater in the physiotherapy group, compared with values for the home-exercise group, 3 and 6 weeks after surgery. Six weeks after surgery, the difference in flexion and extension ROMs was no longer evident between the affected and nonaffected limbs in the physiotherapy group. Both groups had improvements for lameness and weight-bearing scores over time, but no difference was found between the 2 groups. Conclusions and Clinical Relevance-After TPLO in CCL-deficient dogs, early physiotherapy intervention should be considered as part of the postoperative management to prevent muscle atrophy, build muscle mass and strength, and increase stifle joint flexion and extension ROMs.

CORR Insights® : loss of cement-bone interlock in retrieved tibial components from total knee arthroplasties

Most surgeons cement the tibial component in total knee replacement surgery. Mid-term registry data from a number of countries, including those from the United Kingdom and Australia, support the excellent survivorship of cemented tibial components. In spite of this success, results can always be improved, and cementing technique can play a role. Cementing technique on the tibia is not standardized, and surgeons still differ about the best ways to deliver cement into the cancellous bone of the upper tibia. Questions remain regarding whether to use a gun or a syringe to inject the cement into the cancellous bone of the tibial plateau . The ideal cement penetration into the tibial plateau is debated, though most reports suggest that 4 mm to 10 mm is ideal. Thicker mantles are thought to be dangerous due to the risk of bone necrosis, but there is little in the literature to support this contention...