Stimulation of the superficial zone protein and lubrication in the articular cartilage by human platelet-rich plasma.

Background: Platelet-rich plasma (PRP) contains high concentrations of autologous growth factors that originate from platelets. Intra-articular injections of PRP have the potential to ameliorate the symptoms of osteoarthritis in the knee. Superficial zone protein (SZP) is a boundary lubricant in articular cartilage and plays an important role in reducing friction and wear and therefore is critical in cartilage homeostasis.

The effect of drill trajectory on proximity to the posterior interosseous nerve during cortical button distal biceps repair.

Purpose: The aim of this study was to evaluate the effect that different drill trajectories across the radius have on the proximity of the drill tip to the posterior interosseous nerve (PIN).

Methods: In 10 cadaveric specimens, we drilled from the bicipital tuberosity across the radius using 4 different trajectories: (1) aiming across the radius at 90° to the longitudinal axis of the radius, (2) distally at 45°, (3) ulnarly, and (4) radially. We measured the distance between the tip of the drill as it exited the dorsal cortex of the radius and the PIN.