Postpartum osteoporosis associated with proximal tibial stress fracture

A 33-year-old woman presented with acute nonspecific knee pain, 6 months postpartum. MR imaging, computed tomography and radiography were performed and a proximal tibia plateau insufficiency fracture was detected. Bone densitometry demonstrated mild postpartum osteoporosis. To our knowledge these findings have not been described in this location and in this clinical setting. The etiology of the atraumatic fracture of the tibia is presumed to be due to a low bone mineral density. The bone loss was probably due to pregnancy, lactation and postpartum hormonal changes. There were no other inciting causes and the patient was normocalcemic. We discuss the presence of a postpartum stress fracture in a hitherto undescribed site in a patient who had lactated following an uncomplicated pregnancy and had no other identifiable cause for a stress fracture.

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.

Clinically-driven need for secondary interventions after endovascular revascularization of tibial arteries in patients with critical limb ischemia

PURPOSE To assess the need for clinically-driven secondary revascularization in critical limb ischemia (CLI) patients subsequent to tibial angioplasty during a 2-year follow-up. METHODS Between 2008 and 2010, a total of 128 consecutive CLI patients (80 men; mean age 76.5±9.8 years) underwent tibial angioplasty in 139 limbs. Rutherford categories, ankle-brachial index measurements, and lower limb oscillometries were prospectively assessed. All patients were followed at 3, 6, 12 months, and annually thereafter. Rates of death, primary and secondary sustained clinical improvement, target lesion (TLR) and target extremity revascularization (TER), as well as major amputation, were analyzed retrospectively. Primary clinical improvement was defined as improvement in Rutherford category to a level of intermittent claudication without unplanned amputation or TLR. RESULTS All-cause mortality was 8.6%, 14.8%, 22.9%, and 29.1% at 3, 6, 12, and 24 months. At the same intervals, rates of primary sustained clinical improvement were 74.5%, 53.0%, 42.7%, and 37.1%; for secondary improvement, the rates were 89.1%, 76.0%, 68.4%, and 65.0%. Clinically-driven TLR rates were 14.6%, 29.1%, 41.6%, 46.2%; the rates for TER were 3.0%, 13.6%, 17.2%, and 27.6% in corresponding intervals, while the rates of major amputation were 1.5%, 5.5%, 10.1%, and 10.1%. CONCLUSION Clinically-driven TLR is frequently required to maintain favorable functional clinical outcomes in CLI patients following tibial angioplasty. Dedicated technologies addressing tibial arterial restenosis warrant further academic scrutiny.

Early recoil after balloon angioplasty of tibial artery obstructions in patients with critical limb ischemia.

PURPOSE To assess the extent of early recoil in patients with critical limb ischemia (CLI) undergoing conventional tibial balloon angioplasty. METHODS Our hypothesis was that early recoil, defined as lumen compromise >10%, is frequent and accounts for considerable luminal narrowing after tibial angioplasty, promoting restenosis. To test this theory, 30 consecutive CLI patients (18 men; mean age 76.2±12.1 years) were angiographically evaluated immediately after tibial balloon angioplasty and 15 minutes later. Half the patients were diabetics. Target lesions included anterior and posterior tibial arteries and the peroneal artery with / without the tibioperoneal trunk. Mean tibial lesion length was 83.8 mm. Early elastic recoil was determined on the basis of minimal lumen diameter (MLD) measurements at baseline (MLDbaseline), immediately after tibial balloon angioplasty (MLDpostdilation), and 15 minutes thereafter (MLD15min). RESULTS Elastic recoil was observed in 29 (97%) patients with a mean luminal compromise of 29% according to MLD measurements (MLDbaseline 0.23 mm, MLD postdilation 2.0 mm, and MLD15min 1.47 mm). CONCLUSION Early recoil is frequently observed in CLI patients undergoing tibial angioplasty and may significantly contribute to restenosis. These findings support the role of dedicated mechanical scaffolding approaches for the prevention of restenosis in tibial arteries.

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.

Comparison of theoretical fixation stability of three devices employed in medial opening wedge high tibial osteotomy: a finite element analysis.

BACKGROUND Medial open wedge high tibial osteotomy is a well-established procedure for the treatment of unicompartmental osteoarthritis and symptomatic varus malalignment. We hypothesized that different fixation devices generate different fixation stability profiles for the various wedge sizes in a finite element (FE) analysis. METHODS Four types of fixation were compared: 1) first and 2) second generation Puddu plates, and 3) TomoFix plate with and 4) without bone graft. Cortical and cancellous bone was modelled and five different opening wedge sizes were studied for each model. Outcome measures included: 1) stresses in bone, 2) relative displacement of the proximal and distal tibial fragments, 3) stresses in the plates, 4) stresses on the upper and lower screw surfaces in the screw channels. RESULTS The highest load for all fixation types occurred in the plate axis. For the vast majority of the wedge sizes and fixation types the shear stress (von Mises stress) was dominating in the bone independent of fixation type. The relative displacements of the tibial fragments were low (in μm range). With an increasing wedge size this displacement tended to increase for both Puddu plates and the TomoFix plate with bone graft. For the TomoFix plate without bone graft a rather opposite trend was observed.For all fixation types the occurring stresses at the screw-bone contact areas pulled at the screws and exceeded the allowable threshold of 1.2 MPa for at least one screw surface. Of the six screw surfaces that were studied, the TomoFix plate with bone graft showed a stress excess of one out of twelve and without bone graft, five out of twelve. With the Puddu plates, an excess stress occurred in the majority of screw surfaces. CONCLUSIONS The different fixation devices generate different fixation stability profiles for different opening wedge sizes. Based on the computational simulations, none of the studied osteosynthesis fixation types warranted an intransigent full weight bearing per se. The highest fixation stability was observed for the TomoFix plates and the lowest for the first generation Puddu plate. These findings were revealed in theoretical models and need to be validated in controlled clinical settings.

The influence of tibial morphology on the design of an anatomical tibial baseplate for TKA.

BACKGROUND Finding the right balance between tibial coverage and minimal implant overhang is an important factor in TKA. Another significant cause of failure is component malrotation. METHODS An average master shape of the proximal tibia at TKA resection level was calculated using fine slice computed tomographies of 117 cadaveric knees. To find out whether alternate implant contours would be necessary depending on the patient's body size, we established five subgroups to compare. CAD-Analysis was performed to simulate the overhang produced after ±4°/±7°/±10° rotation. RESULTS A master shape for the tibial resection cut (with a 5° posterior slope, 7 mm under lateral joint line) could be determined. Neither left vs. right knee joint, nor male vs. female nor the size subdivision appears to alter the calculated master shape significantly. The optimized shape allowing for ±4° of rotational freedom was found to be the best variant. CONCLUSIONS Valid methods have been obtained to design a two-dimensional average shape of the tibial plateau. The modifications described in this study might come in useful, when designing future implant designs. CLINICAL RELEVANCE An optimized fit at the tibial plateau and lower rates of component malrotation may result in better outcomes after TKA.

Complete rupture of the popliteal artery complicating high tibial osteotomy.

We present two cases of high tibial osteotomies performed at our institution. Both cases were complicated with the immediate postoperative occurrence of an ischaemic syndrome of the lower leg. Urgent diagnostics revealed a complete rupture of the popliteal artery that required re-operation and a vascular repair. Although neurovascular complications during high tibial osteotomies are rare the awareness of this potentially catastrophic complication should be present when performing this common procedure. All precautions to minimize the harm to the neurovascular bundle should be put into practice. A summary of the surgical precautions is presented and discussed in this paper.

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.