Hip capsule dimensions in patients with femoroacetabular impingement: a pilot study

Joint-preserving hip surgery, either arthroscopic or open, increasingly is used for the treatment of symptomatic femoroacetabular impingement (FAI). As a consequence of surgery, thickening of the joint capsule and intraarticular adhesions between the labrum and joint capsule and between the femoral neck and the joint capsule have been observed. These alterations are believed to cause persistent pain and reduced range of motion. Because the diagnosis is made with MR arthrography, knowledge of the normal capsular anatomy and thickness on MRI in patients is important. To date there is no such information available.

Does bone wax induce a chronic inflammatory articular reaction?

Bone wax is used to control femoral neck bleeding during open femoroacetabular impingement (FAI) surgery. Despite its widespread use, only a few case reports and small case series describe side effects after extraarticular use. It is unclear whether intraarticular use of bone wax leads to such complications. However, during revision FAI surgery, we have observed various degrees of articular inflammatory reactions.

More accurate component alignment in navigated total knee arthroplasty has no clinical benefit at 5-year follow-up

Computer navigation in total knee arthroplasty is somewhat controversial. We have previously shown that femoral component positioning is more accurate with computed navigation than with conventional implantation techniques, but the clinical impact of this is unknown. We now report the 5-year outcome of our previously reported 2-year outcome study.

Bioabsorbable pins for treatment of osteochondral fractures of the knee after acute patella dislocation in children and young adolescents

A retrospective study was performed on the use of bioabsorbable pins in the fixation of osteochondral fractures (OCFs) after traumatic patellar dislocation in children. Eighteen children (13 females, 5 males) aged 11 to 15 years (mean age 13.1 years) with osteochondral fracture (OCF) of the knee joint were treated at the authors' institution. Followup ranged from 22 months to 5 years. Diagnosis was verified by X-ray and magnetic resonance imaging (MRI) of the knee and patella. In seven patients the osteochondral fragment was detached from the patella and in 11 it was detached from the lateral femoral condyle. All patients were subjected to open reduction and fixation of the lesion with bioabsorbable pins. Postoperatively, the knee was immobilized in a cast and all patients were mobilized applying a standardized protocol. Bone consolidation was successful in 17 of the 18 patients. Bioabsorbable pins reliably fix OCF in children and adolescents, demonstrating a high incidence of consolidation of the detached osteochondral fragment in short- and middle-term followup without requiring further operative procedures.

Early detection of subclinical organ dysfunction by microdialysis of the rectus abdominis muscle in a porcine model of critical intra-abdominal hypertension

The aim of this study was to evaluate microdialysis of the rectus abdominis muscle (RAM) for early detection of subclinical organ dysfunction in a porcine model of critical intra-abdominal hypertension (IAH). Microdialysis catheters for analyses of lactate, pyruvate, and glycerol levels were placed in cervical muscles (control), gastric and jejunal wall, liver, kidney, and RAM of 30 anesthetized mechanically ventilated pigs. Catheters for venous lactate and interleukin 6 samples were placed in the jugular, portal, and femoral vein. Intra-abdominal pressure (IAP) was increased to 20 mmHg (IAH20 group, n = 10) and 30 mmHg (IAH30, n = 10) for 6 h by controlled CO2 insufflation, whereas sham animals (n = 10) exhibited a physiological IAP. In contrast to 20 mmHg, an IAH of 30 mmHg induced pathophysiological alterations consistent with an abdominal compartment syndrome. Microdialysis showed significant increase in the lactate/pyruvate ratio in the RAM of the IAH20 group after 6 h. In the IAH30 group, the strongest increase in lactate/pyruvate ratio was detected in the RAM and less pronounced in the liver and gastric wall. Glycerol increased in the RAM only. After 6 h, there was a significant increase in venous interleukin 6 of the IAH30 group compared with baseline. Venous lactate was increased compared with baseline and shams in the femoral vein of the IAH30 group only. Intra-abdominal pressure-induced ischemic metabolic changes are detected more rapidly and pronounced by microdialysis of the RAM when compared with intra-abdominal organs. Thus, the RAM represents an important and easily accessible site for the early detection of subclinical organ dysfunction during critical IAH.

The Locking Compression Paediatric Hip Plate: technical guide and critical analysis

Osteotomies of the proximal femur and stable fixation of displaced femoral neck fractures are demanding operations. An LCP Paediatric Hip Plate was developed to make these operations safer and less demanding. The article focuses on the surgical technique and critically analyses the device.

Transcatheter aortic valve implantation: the procedure

Transcatheter aortic valve implantation (TAVI) for the treatment of symptomatic severe aortic stenosis has emerged as an effective treatment for high risk patients. In 2002 TAVI was performed for the first time in a human by Alain Cribier, using an antegrade access approach via the femoral vein, crossing the intra-atrial septum after puncture and passing the native aortic valve in the direction of blood flow. This technically demanding approach was subsequently replaced by retrograde transfemoral arterial access. For patients with severe peripheral vascular disease or inadequately sized femoral arteries, the transapical route provides an alternative route with antegrade access to the aortic valve via puncture of the anterolateral wall of the left ventricle. The transsubclavian access approach using most frequently the left subclavian artery and direct transaortic access have been introduced more recently and attest to the versatility of TAVI in terms of access site. This article will focus on the different access site options available to operators, provide a step-by-step guide through the procedure, and a detailed description of the technological evolution of transcatheter heart valve systems.

Correlation of Pullout Force of Kirschner (K-) Wire to Other Factors Indicative of Bone Quality

More than 250,000 hip fractures occur annually in the United States and the most common fracture location is the femoral neck, the weakest region of the femur. Hip fixation surgery is conducted to repair hip fractures by using a Kirschner (K-) wire as a temporary guide for permanent bone screws. Variation has been observed in the force required to extract the K-wire from the femoral head during surgery. It is hypothesized that a relationship exists between the K-wire pullout force and the bone quality at the site of extraction. Currently, bone mineral density (BMD) is used as a predictor for bone quality and strength. However, BMD characterizes the entire skeletal system and does not account for localized bone quality and factors such as lifestyle, nutrition, and drug use. A patient’s BMD may not accurately describe the quality of bone at the site of fracture. This study aims to investigate a correlation between the force required to extract a K-wire from femoral head specimens and the quality of bone. A procedure to measure K-wire pullout force was developed and tested with pig femoral head specimens. The procedure was implemented on 8 human osteoarthritic femoral head specimens and the average pullout force for each ranged from 563.32 ± 240.38 N to 1041.01 ± 346.84 N. The data exhibited significant variation within and between each specimen and no statistically significant relationships were determined between pullout force and patient age, weight, height, BMI, inorganic to organic matter ratio, and BMD. A new testing fixture was designed and manufactured to merge the clinical and research environments by enabling the physician to extract the K-wire from each bone specimen himself. The new device allows the physician to gather tactile feedback on the relative ease of extraction while load history is recorded similar to the previous procedure for data acquisition. Future work will include testing human bones with the new device to further investigate correlations for predicting bone quality.

Stent placement versus balloon angioplasty for the treatment of obstructive lesions of the popliteal artery: a prospective, multicenter, randomized trial

Stenting has been shown to improve patency after femoral artery revascularization compared with balloon angioplasty. Limited data are available evaluating endovascular treatment for obstructive lesions of the popliteal artery.

The structural architecture of adult mammalian articular cartilage evolves by a synchronized process of tissue resorption and neoformation during postnatal development

OBJECTIVE: During postnatal development, mammalian articular cartilage acts as a surface growth plate for the underlying epiphyseal bone. Concomitantly, it undergoes a fundamental process of structural reorganization from an immature isotropic to a mature (adult) anisotropic architecture. However, the mechanism underlying this structural transformation is unknown. It could involve either an internal remodelling process, or complete resorption followed by tissue neoformation. The aim of this study was to establish which of these two alternative tissue reorganization mechanisms is physiologically operative. We also wished to pinpoint the articular cartilage source of the stem cells for clonal expansion and the zonal location of the chondrocyte pool with high proliferative activity. METHODS: The New Zealand white rabbit served as our animal model. The analysis was confined to the high-weight-bearing (central) areas of the medial and lateral femoral condyles. After birth, the articular cartilage layer was evaluated morphologically at monthly intervals from the first to the eighth postnatal month, when this species attains skeletal maturity. The overall height of the articular cartilage layer at each juncture was measured. The growth performance of the articular cartilage layer was assessed by calcein labelling, which permitted an estimation of the daily growth rate of the epiphyseal bone and its monthly length-gain. The slowly proliferating stem-cell pool was identified immunohistochemically (after labelling with bromodeoxyuridine), and the rapidly proliferating chondrocyte population by autoradiography (after labelling with (3)H-thymidine). RESULTS: The growth activity of the articular cartilage layer was highest 1 month after birth. It declined precipitously between the first and third months, and ceased between the third and fourth months, when the animal enters puberty. The structural maturation of the articular cartilage layer followed a corresponding temporal trend. During the first 3 months, when the articular cartilage layer is undergoing structural reorganization, the net length-gain in the epiphyseal bone exceeded the height of the articular cartilage layer. This finding indicates that the postnatal reorganization of articular cartilage from an immature isotropic to a mature anisotropic structure is not achieved by a process of internal remodelling, but by the resorption and neoformation of all zones except the most superficial (stem-cell) one. The superficial zone was found to consist of slowly dividing stem cells with bidirectional mitotic activity. In the horizontal direction, this zone furnishes new stem cells that replenish the pool and effect a lateral expansion of the articular cartilage layer. In the vertical direction, the superficial zone supplies the rapidly dividing, transit-amplifying daughter-cell pool that feeds the transitional and upper radial zones during the postnatal growth phase of the articular cartilage layer. CONCLUSIONS: During postnatal development, mammalian articular cartilage fulfils a dual function, viz., it acts not only as an articulating layer but also as a surface growth plate. In the lapine model, this growth activity ceases at puberty (3-4 months of age), whereas that of the true (metaphyseal) growth plate continues until the time of skeletal maturity (8 months). Hence, the two structures are regulated independently. The structural maturation of the articular cartilage layer coincides temporally with the cessation of its growth activity - for the radial expansion and remodelling of the epiphyseal bone - and with sexual maturation. That articular cartilage is physiologically reorganized by a process of tissue resorption and neoformation, rather than by one of internal remodelling, has important implications for the functional engineering and repair of articular cartilage tissue.

Detection and distribution of apoptotic cell death in normal and diseased canine cranial cruciate ligaments

One of the possible initiating factors in canine cranial cruciate ligament (CCL) rupture could be an abnormal pattern of ligament cell death. This study compared apoptotic cell death in sections of ruptured CCLs and normal controls, and examined nitric oxide (NO) production in joint tissues and correlated this to apoptosis. CCLs and cartilage from the lateral femoral condyle were harvested from 10 healthy dogs and 15 dogs with CCL rupture and ligaments were further processed to detect cleaved caspase-3 and to determine supernatant NO production in explant cultures. Apoptotic activity was greater in ruptured ligaments compared to controls. NO in ligaments showed a moderate but significant positive correlation with caspase-positive cells. The results suggest that increased apoptosis has a role in CCL rupture and that apoptosis may be influenced by local NO production.

Acute compartment syndrome complicating an intramuscular haemangiosarcoma in a dog

Acute compartment syndrome in dogs is a rare complication of muscle trauma, but it has not been previously reported as a consequence of neoplasia in dogs. This case report describes the occurrence of a compartment syndrome of the femoral compartment in an 11-year-old, male, mixed-breed dog caused by acute bleeding of an intramuscular haemangiosarcoma. The compartment syndrome was relieved by immediate fasciotomy. The dog was euthanased following acute recurrence of clinical signs seven weeks after surgery.

[Guidance of interventions in subintimal recanalization and fenestration of dissection membranes using a novel dual-lumen intravascular ultrasound catheter]

PURPOSE: To evaluate the feasibility and effectiveness of IVUS-guided puncture for gaining controlled target lumen reentry in subintimal recanalization of chronic iliac/femoral artery occlusions and in fenestration of aortic dissections. MATERIALS AND METHODS: Between 5/2004 and 12/2005 12 consecutive patients (7 male, 5 female; mean age 64.6 +/- 12.0 years) with chronic critical limb ischemia and ischemic complications of aortic dissection were treated using the Pioneer catheter. This 6.2-F dual-lumen catheter combines a 20-MHz IVUS transducer with a pre-shaped extendable, hollow 24-gauge nitinol needle. This coaxial needle allows real-time IVUS-guided puncture of the target lumen and after successful reentry a 0.014" guidewire may be advanced through the needle into the target lumen. 7 patients were treated for aortic dissection and 5 patients (with failed previous attempts at subintimal recanalization) for chronic arterial occlusion. Patients with aortic dissection (5 type A dissections, 2 type B dissections) had developed renal ischemia (n = 2), renal and mesenteric ischemia (n = 2), or low extremity ischemia (n = 3). Patients with chronic arterial occlusions (2 common iliac artery occlusions, 3 superficial femoral artery occlusions) experienced ischemic rest pain (n = 4), and a non-healing foot ulcer (n = 1). RESULTS: The technical success rate using the Pioneer catheter was 100%. The recanalization/fenestration time was 37 +/- 12 min. Procedure-related complications did not occur. In 10 cases a significant improvement of clinical symptoms was evident. One patient with aortic dissection and ischemic paraplegia required subsequent surgical intervention. One patient had persistent ischemic rest pain despite successful recanalization of a superficial femoral artery occlusion. CONCLUSION: The Pioneer catheter is a reliable device which may be helpful for achieving target lumen reentry in subintimal recanalization of chronic occlusions and in fenestration of aortic dissections.

Lymphatic clearance of the human skin in patients with acute deep vein thrombosis using a novel fluorescent technique

The purpose of this study was to investigate lymphatic clearance of the human skin in patients with acute deep thrombosis of the femoral vein. In 13 patients with deep vein thrombosis and no other cause for swelling of the limbs, lymphatic clearance of the skin at the foot was measured. Ten microliters of fluorescein isothiocyanatedextran 150,000 were injected intradermally and the fluorescent light intensity of the deposit measured 10 min and 24 hours after injection by window densitometry. In addition, intralymphatic pressure was measured by the servo-nulling system. The results were compared with a sex- and age-matched control group. Fluorescent light intensity decreased by 23.8 +/- 12.3 arbitrary units or by a factor of 1.8 +/- 0.5 in patients with DVT after 24 hours, which was significantly less than in healthy controls (33.7 +/- 8.9 arbitrary units or by factor 5.0 +/- 4.1, p < 0.013). Intralymphatic pressure was not different between the two groups. These results indicate that lymphatic clearance is significantly reduced in the acute phase of deep venous thrombosis.

Assessing intravascular volume by difference in pulse pressure in pigs submitted to graded hemorrhage

We assessed changes in intravascular volume monitored by difference in pulse pressure (dPP%) after stepwise hemorrhage in an experimental pig model. Six pigs (23-25 kg) were anesthetized (isoflurane 1.5 vol%) and mechanically ventilated to keep end-tidal CO2 (etCO2) at 35 mmHg. A PA-catheter and an arterial catheter were placed via femoral access. During and after surgery, animals received lactated Ringer's solution as long as they were considered volume responders (dPP>13%). Then animals were allowed to stabilize from the induction of anesthesia and insertion of catheters for 30 min. After stabilization, baseline measurements were taken. Five percent of blood volume was withdrawn, followed by another 5%, and then in 10%-increments until death from exsanguination occurred. After withdrawal of 5% of blood volume, all pigs were considered volume responders (dPP>13%); dPP rose significantly from 6.1+/-3.3% to 19.4+/-4.2%. The regression analysis of stepwise hemorrhage revealed a linear relation between blood loss (hemorrhage in %) and dPP (y=0.99*x+14; R2=0.7764; P<.0001). In addition, dPP was the only parameter that changed significantly between baseline and a blood loss of 5% (P<0.01), whereas cardiac output, stroke volume, heart rate, MAP, central venous pressure, pulmonary artery occlusion pressure, and systemic vascular resistance, respectively, remained unchanged. We conclude that in an experimental hypovolemic pig model, dPP correlates well with blood loss.