Polyacrylamide Hydrogel Injection for Knee Osteoarthritis: A 6 Months Prospective Study

Objective: Intra-Articular (IA) injection of polyacrylamide hydrogel (PAAG) is a possible treatment for symptomatic Osteoarthritis (OA) of the knee. This study evaluated the efficacy and safety of a single injection of 6 ml intra-articular PAAG over 26 weeks. Methods: Open-label study in patients with symptomatic and radiographically confirmed knee OA . Primary outcome was change in WOMAC pain after 13 weeks. Secondary outcomes were WOMAC stiffness and function subscales, Patient Global Assessment of disease impact (PGA) and proportion of OMERACT-OARSI responders. Follow-up time points were 4, 13 and 26 weeks. Results: 49 patients (31 females) received PAAG, with 48 patients completing the 13 and 46 the 26 weeks assessments. Mean change in WOMAC pain after 13 weeks was -18.3 points [95% CI-23.4 to -13.3]; P<.0001 and at 26 weeks -20.8 points [95% CI -26.3 to -15.3]; P<0.0001 with similar benefits for WOMAC stiffness, physical function, and PGA. After 13 weeks 64.6% were OMERACT-OARSI responders and this was maintained at 26 weeks.. During the 13 weeks, 18 patients reported 23 adverse events, 13 of which were related to PAAG, none severe. Two serious adverse events, atrial fibrillation and gastrointestinal pain, were assessed as ‘not related’ to PAAG. Conclusions: PAAG can be delivered in a single 6 ml injection and this non-randomized trial in patients with knee OA demonstrated beneficial clinical effects at 13 and 26 weeks. No serious adverse events were seen with PAAG. These encouraging results need to be confirmed in controlled studies

Effect of training on contractile and metabolic properties of wrist extensors in spinal cord-injured individuals

Paretic human muscle rapidly loses strength and oxidative endurance, and electrical stimulation training may partly reverse this. We evaluated the effects of two training protocols on the contractile and metabolic properties of the wrist extensor in 12 C-5/6 tetraplegic individuals. The wrist extensor muscles were stimulated for 30 min/day, 5 days/week, for 12 weeks, using either a high-resistance (Hr) or a low-resistance (Lr) protocol. Total work output was similar in both protocols. The nontrained arm was used as a control. Maximum voluntary torque increased in the Hr (P < 0.05) but not the Lr group. Electrically stimulated peak tetanic torque at 15 HZ, 30 HZ, and 50 HZ were unchanged in the Lr group and tended to increase only at 15 HZ (P < 0.1) in the Hr group. Resistance to fatigue, however, increased (P < 0.05) in both Hr (42%) and Lr (41%) groups. Muscle metabolism was evaluated by (31)P nuclear magnetic resonance spectroscopy ((31)P-NMRS) during and following a continuous 40-s 10-HZ contraction. In the Hr group the cost of contraction decreased by 38% (P < 0.05) and the half-time of phosphocreatine (PCr) recovery was shortened by 52% (P < 0.05). Thus, long-term electrically induced stimulation of the wrist extensor muscles in spinal cord injury (SCI) increases fatigue resistance independent of training pattern. However, only the Hr protocol increased muscle strength and was shown to improve muscle aerobic metabolism after training. Muscle Nerve 27: 72-80, 200