Accelerometer-Based, Portable Navigation (KneeAlign) vs Conventional Instrumentation for Total Knee Arthroplasty: A Prospective Randomized Comparative Trial.

BACKGROUND: Accelerometer-based, portable navigation devices have been introduced as a less invasive and simpler technique to perform navigated surgical implantation of knee prostheses. They have been postulated to have better accuracy than conventional instruments in restoration of alignment in total knee arthroplasty. METHODS: A total of 190 patients were enrolled in this prospective, randomized controlled trial and underwent total knee arthroplasty using either the KneeAlign or conventional guides. Multiplanar alignment was evaluated with a CT imaging protocol. RESULTS: A total of 86.5% of portable navigation device and 82.2% of conventional group had a postoperative hip-knee angle within 3° of neutral alignment (P = .54). There was no significant difference between the 2 groups for component coronal and sagittal plane alignment. Portable navigation device did not significantly increase the time to perform the surgery. CONCLUSION: Portable navigation device demonstrates accurate restoration of alignment; however, there was no statistically significant difference when compared with conventional guides.

Analgesic control and functional outcome after knee arthroscopy: results of a randomized double-blinded trial comparing a hyaluronic acid supplement with bupivacaine.

OBJECTIVE: Hyaluronic acid (HA) is a naturally occurring substance within normal synovial joints. Although its efficacy in treating osteoarthritis has been evaluated, it has not been established whether it is of benefit after routine arthroscopic procedures. We hypothesized that immediate supplementation with HA after completion of arthroscopy would result in improved short-term analgesic and functional outcomes after knee arthroscopy. DESIGN: Double-blinded randomized controlled trial. SETTING: Tertiary referral center. PATIENTS: One hundred ten patients presenting for routine arthroscopic procedures were invited to participate in the study. After exclusion criteria were applied, 98 patients were randomized to receive either 10 mL of 0.5% bupivacaine or 3 mL of HA into the joint immediately after completion of surgery. INTERVENTIONS: After completion of surgery, all patients were randomized to receive either 10 mL of 0.5% bupivacaine or 3 mL of HA into the knee joint. MAIN OUTCOME MEASURES: Visual analogue scale (VAS) pain scores were obtained at baseline; 1, 2, and 24 hours; and 1, 2, and 6 weeks after surgery. Western Ontario and McMaster Universities (WOMAC) and Tegner-Lysholm scores were obtained at baseline and then at 1, 2, and 6 weeks after surgery. RESULTS: Forty-nine patients received intra-articular bupivacaine and 49 received HA. There was no statistical difference in any of the outcome measures (VAS pain scores, WOMAC, and Tegner-Lysholm) at any time point between the groups overall. CONCLUSIONS: There was no benefit of HA injection immediately at the end of knee arthroscopy in the first 6 weeks after surgery. CLINICAL RELEVANCE: Routine use of HA at the time of knee arthroscopy cannot be recommended.

The effect of a new direct Factor Xa inhibitor on human osteoblasts: an in-vitro study comparing the effect of rivaroxaban with enoxaparin.

BACKGROUND: Current treatments for the prevention of thromboembolism include heparin and low-molecular weight heparins (LMWHs). A number of studies have suggested that long term administration of these drugs may adversely affect osteoblasts and therefore, bone metabolism. Xarelto™ (Rivaroxaban) is a new anti-thrombotic drug for the prevention of venous thromboembolism in adult patients undergoing elective hip and knee replacement surgery. The aim of this in vitro study was to investigate the possible effects of rivaroxaban on osteoblast viability, function and gene expression compared to enoxaparin, a commonly used LMWH. METHODS: Primary human osteoblast cultures were treated with varying concentrations of rivaroxaban (0.013, 0.13, 1.3 and 13 µg/ml) or enoxaparin (1, 10 and 100 µg/ml). The effect of each drug on osteoblast function was evaluated by measuring alkaline phosphatase activity. The MTS assay was used to assess the effect of drug treatments on cell proliferation. Changes in osteocalcin, Runx2 and BMP-2 messenger RNA (mRNA) expression following drug treatments were measured by real-time polymerase chain reaction (PCR). RESULTS: Rivaroxaban and enoxaparin treatment did not adversely affect osteoblast viability. However, both drugs caused a significant reduction in osteoblast function, as measured by alkaline phosphatase activity. This reduction in osteoblast function was associated with a reduction in the mRNA expression of the bone marker, osteocalcin, the transcription factor, Runx2, and the osteogenic factor, BMP-2. CONCLUSIONS: These data show that rivaroxaban treatment may negatively affect bone through a reduction in osteoblast function.