This loading situation most closely approximates physiologic loading and therefore represents an ideal outcome for patients with isolated chondral defects. Reduction in stress concentration around chondral defects has been found to favor cartilage repair.

Metal-on-metal total hip resurfacing is a bone-conserving reconstructive option for patients with advanced articular damage. While intended to address several problems with conventional THA, the safety and efficacy is not well established. We therefore retrospectively compared the outcomes of 52 patients (57 hips) with resurfacing arthroplasty to 84 patients (93 hips) with cementless primary THAs. The patients had a minimum 2-year followup (mean 3 years). The patients with resurfacing arthroplasty had a mean age of 47 years (range, 22-64) while those with cementless primary THA had a mean age of 57 years (range, 17-92). After controlling for age, gender, and preoperative differences, the total Harris Hip Scores (HHS), function scores, and pain scores were similar between the two groups. However, the resurfacing group had higher activity scores (14 versus 13, p < 0.001) and range of motion (ROM) scores (5.0 versus 4.8, p < 0.001). The complication rates (5.3% for resurfacing versus 14.0% for THA) and reoperation rates (3.5% for resurfacing versus 4.3% for THA) were similar. The total hip arthroplasty and metal-on-metal resurfacing groups both showed improvement in HHS, pain, activity, and ROM and had similar early complication and reoperation rates.

Intraspinous and pedicle screw-based (PSB) dynamic instrumentation systems have been in use for a decade now. By direct or indirect decompression, these devices theoretically establish less painful segmental motion by diminishing pathologic motion and unloading painful disks. Ideally, dynamics should address instability in the early stages of degenerative spondylolisthesis before excessive translation occurs. Evidence to date indicates that Grade II or larger slips requiring decompression should be fused. In addition, multiple segment listhesis, severe coronal plane deformities, increasing age, and osteoporosis have all been listed as potential contraindications to dynamic stabilization. We reviewed the exclusion and inclusion criteria found in various dynamic stabilization studies and investigational drug exemption (IDE) protocols. We summarize the reported limitations for both pedicle-and intraspinous-based systems. We then conducted a retrospective chart and imaging review of 100 consecutive cases undergoing fusion for degenerative spondylolisthesis. All patients in our cohort had been indicated for and eventually underwent decompression of lumbar stenosis secondary to spondylolisthesis. We estimated how many patients in our population would have been candidates for dynamic stabilization with either interspinous or pedicle-based systems. Using the criteria for instability outlined in the literature, 32 patients demonstrated translation requiring fusion surgery and 24 patients had instability unsuitable for dynamic stabilization. Six patients had two-level slips and were excluded. Two patients had coronal imbalance too great for dynamic systems. Twelve patients were over the age of 80 and 16 demonstrated osteoporosis as diagnosed by bone scan. Finally, we found two of our patients to have vertebral compression fractures adjacent to the site of instrumentation, which is a strict exclusion criteria in all dynamic trials. Thirty-four patients had zero exclusion criteria for intraspinous devices and 23 patients had none for PSB dynamic stabilization. Therefore, we estimate that 34 and 23% of degenerative spondylolisthesis patients indicated for surgery could have been treated with either intraspinous or pedicle-based dynamic devices, respectively.

Thrombosis Cosmi B, Legnani C, Cini M. Thromb Res 2008;122:610-7.Conclusion: Elevated levels of D-dimer and factor VIII at 30 Ϯ 10 days after cessation of vitamin K antagonist (VKA) therapy for a first episode of idiopathic proximal deep venous thrombosis (DVT) are independent risk factors for recurrent venous thromboembolism (VTE).Summary: The optimal duration of VKA therapy after a first episode of VTE is unknown. It appears VKA extension after unprovoked VTE can reduce the risk of recurrent VTE but at the potential price of increased bleeding. There is therefore intense interest in stratifying patients with idiopathic VTE with respect to risk factors that may increase rates of recurrence. The specific objective of this study was to assess the risk of recurrence of VTE associated with elevated D-dimer levels and factor VIII levels after withdrawal of VKA therapy for symptomatic idiopathic proximal VTE.Consecutive outpatients with the first episode of idiopathic proximal DVT were enrolled into the study after cessation of VKA therapy. At 30 Ϯ 10 days after cessation of VKA therapy, levels of D-dimer (cutoff value, 500 ng/mL) and chromogenic factor VIII, as well as inherited thrombophilias were determined. Follow-up extended for 2 years.Overall recurrence rate of VTE was 16.4% (55 of 336; 95% confidence interval [CI], 13%-21%). The multivariate hazard ratio for recurrence was 2.45 (95% CI, 1.24-4.99) for abnormal D-dimer and 2.76 (95% CI, 1.57-4.85) for factor VIII Ͼ75th percentile (2.42 /mL). The values were adjusted for age, sex, and thrombophilia. Compared with normal levels of D-dimer and factor VIII, the multivariate hazard ratio was 4.5 (95% CI, 1.7-12.2) for normal D-dimer levels with factor VIII Ͼ2.42 U/mL, and 2.7 (95% CI, 1.2-6.6) and 7.1 (95% CI, 2.8-17.6) for abnormal D-dimer with factor VIII, respectively, below and above 2.42 U/mL. Comment: The appropriate length of treatment with VKA therapy for patients with idiopathic VTE is unknown. The data suggest the longer the treatment period with VKA, the less the recurrence rates of VTE. Of course, VKAs are associated with increased risk of bleeding and are inconvenient for the patient. There is therefore intense interest in stratifying risk among those patients with idiopathic VTE. This is another study that attempts to do just that. The percentage of patients with both normal D-dimer and factor VIII Ͻ75th percentile was 37%. This implies that at least a third of patients with idiopathic VTE have a low risk of VTE recurrence. Larger studies are warranted to determine if the combination of factor VIII and D-dimer analysis can be used to tailor duration of VKA therapy after idiopathic VTE.