Efficacy of intraarticular hyaluronic acid injections in knee osteoarthritis.

Intraarticular injections of hyaluronic acid have been advocated for treatment of symptomatic knee osteoarthritis. Appropriate indications and favorable patient response factors, such as radiographic disease severity and age, are not clearly defined for this therapy. The current review of 80 knees with symptomatic osteoarthritis treated with hyaluronic acid revealed that approximately 2/3 of treated knees received 2/3 relief of pain. Hyaluronic acid treatment is not appropriate for all patients with knee osteoarthritis. Overall, less than 50% of treated knees achieved satisfactory results, and only 35% reported increased activity. Twenty-two patients (28% of knees; 22 knees) underwent surgery within 7 months of their index injection, suggesting an inadequate response to treatment. The treatment is not without complication because 11 patients (15% of knees; 12 knees) experienced adverse reactions, including one case of septic arthritis. The authors recommend intraarticular hyaluronic acid only for patients with symptoms and significant surgical risk factors and for patients with mild radiographic disease in whom conservative treatment has failed (physical therapy, weight loss, nonsteroidal antiinflammatory medication, and intraarticular steroid injection). It is inadvisable to treat patients with a complete collapse of joint space or bone loss with intraarticular hyaluronic acid, given their poor clinical response.

Ten- to 14-year clinical followup of the cementless Natural Knee system.

Of 300 consecutive knees (238 patients) that had undergone arthroplasty with the cementless Natural Knee prosthesis from 1985 to 1989, 176 knees (141 patients) were available for followup at an average of 12 +/- 1 years after the operation. Knee function was improved significantly. Modified Hospital for Special Surgery knee scores improved from 59.1 +/- 13.2 points preoperatively to 97.8 +/- 4.7 points at last followup. At last followup, knee range of motion averaged 0 degrees +/- 2 degrees to 120 degrees +/- 10 degrees. Implant survival was 93.4% (including infection and simple polyethylene exchanges) and 95.1% (excluding infection and simple polyethylene exchanges) at 10 years when applying the Kaplan-Meier survival analysis, using loose components, revision, or both as failure criteria. Besides the three revisions for infection, only two femoral and one tibial component required revision. The patellar component survivorship at 10 years was 95.1%. All patellar revisions were attributed to edge wear. Subsequent operative and design changes, including patellar component medialization and countersinking, have decreased the incidence of patellar revision. The long-term results of this cementless knee system compare favorably with those of cemented systems. The Natural Knee design has provided excellent and predictable long-term clinical results in the current series of active patients.

Culture-negative septic arthritis in children.

To compare the incidence, characteristics, treatment course, and clinical outcome of children with culture-negative versus culture-positive septic arthritis, we reviewed all 105 children treated for septic arthritis at our institution from 1990 to 1997. Seventy-six children had a clinical presentation consistent with an isolated joint infection. All underwent a joint aspiration with fluid analysis including culture. All were followed up until resolution of their symptoms. Culture of the synovial aspirates identified an etiologic organism in only 30% of cases. No significant differences existed between the culture-positive and culture-negative groups in most clinical and laboratory criteria. No other diagnoses were demonstrated. All patients underwent joint drainage, received comparable antibiotic therapy, and had complete resolution of their infections. The current literature reports deceptively low rates of 18-48% for culture-negative septic arthritis. Seventy percent of children with clinical findings of septic arthritis had negative synovial fluid cultures. As the two culture groups were comparable and no other diagnoses were demonstrated, the culture-negative cases were likely infections. Thus we recommend the same aggressive treatment in those cases with and without identification of a causative organism.