PHILADELPHIA – Home exercise DVDs do not enhance long-term adherence to prescribed exercise in patients with knee osteoarthritis, despite producing substantial improvements in pain and physical function at 2 years in a randomized controlled trial.
As with most home exercise DVDs, things started off great.
Patrice Wendling/IMNG Medical Media
Dr. Harukazu Tohyama
Patients who took home a 30-minute DVD after watching it alongside a physiotherapist reported exercising 5.5 and 5.1 times per week at 3 months and 6 months, compared with just 4.3 and 3.9 times per week among controls given detailed verbal and hands-on instruction in a quadriceps exercise protocol, but no video (P = .0358; P =.0369).
At 12 months and 24 months, however, there was no significant difference in exercise adherence between the two groups (P = .169; P = .324), Dr. Harukazu Tohyama said at the World Congress on Osteoarthritis.
The investigators also hypothesized that use of a home exercise DVD could prevent radiographic progression of knee osteoarthritis (OA), but this was not the case among the study’s 107 patients.
The DVD group showed a significant increase in femorotibial angle at 12 and 24 months over baseline values (both P less than .05), but the difference between groups was not significant at either time point (P = .334; P = .293), said Dr. Tohyama, who is on the faculty of the department of sports medicine at Hokkaido University in Sapporo, Japan.
Joint space area, minimum joint space width, and osteophyte area were also similar between groups, as assessed using a fully automated knee OA computer-aided diagnosis (KOA-CAD) measuring system (Osteoarthritis Cartilage. 2008;16:1300-6).
The DVD-based program encompassed muscle stretching, active range-of-motion exercises, and five forms of muscle strengthening. Both the DVD and control group had their intervention reinforced at a clinic visit 4 weeks after randomization.
Members of the audience suggested that a single visit at 4 weeks without additional boosters is not enough to promote adherence. They also questioned whether a 24-month follow-up is long enough to detect whether OA progression is occurring, and cautioned that the study numbers may be too small to draw such a conclusion.
Dr. Tohyama responded that a 24-month follow-up is sufficient for joint OA, but that "for joint [space] narrowing, 24 months is not enough. We need longer follow-up."
Of the 107 patients randomized, 48 were available for analysis in the DVD group and 23 in the control group. The remainder was lost to follow-up or refused the allocation.
The patients were more than 50 years old and had Kellgren-Lawrence grade 2, 3, or 4 knee OA and knee pain. Patients requiring regular or intermittent use of steroids or nonsteroidal anti-inflammatory drugs were excluded.
Scores on the WOMAC (Western Ontario and McMaster Universities Arthritis Index) for all categories were significantly greater in the DVD group than in the control group at 3, 6, 12, and 24 months, Dr. Tohyama said at the meeting, which was sponsored by the Osteoarthritis Research Society International.
WOMAC scores at 6 months in the DVD and control groups were 2.7 vs. 0.2 for pain (P = .0001), 0.60 vs. –0.20 for stiffness (P = .0020), and 8.3 vs. 0.7 for function (P = .0001).
At 24 months, the corresponding scores were 2.2 vs. 0.6 (P = .023), 0.60 vs. –0.07 (P = .011), and 7.3 vs. 2.3 (P = .014).
Improvement in the physical component of the Short Form-8 Health Survey was also significantly greater in the DVD group than in the control group at 3, 6, and 12 months (12 months: 8.3 vs. 2.3; P = .002), but not at 24 months (7.1 vs. 4.1; P = .07).
No significant between-group differences were observed on the SF-8 mental component at any of the time points, he said.
Body mass decreased significantly early on in the DVD group, at 3 and 6 months, compared with controls, but the decline waned along with adherence, and was no longer significant at 12 or 24 months.
Although exercise DVDs may be popular and engaging, "I think what is most important for adherence improvement is to form an exercise habit," Dr. Tohyama said in an interview.
The Japanese Orthopaedic Association sponsored the study. Dr. Tohyama reported having no financial disclosures.