Knee Osteoarthritis and Degenerative Meniscal Tear: Lessons from Two 2025 Trials

By Ellen Feldman, MD

Synopsis: Two high-quality, randomized studies demonstrate the effectiveness of unsupervised exercise programs for knee osteoarthritis and degenerative menisical tear.

Sources: Zhu SJ, Hinman RS, Lawford BJ, et al. Online unsupervised Tai Chi intervention for knee pain and function in people with knee osteoarthritis: The RETREAT randomized clinical trial. JAMA Intern Med. 2025; Oct 27. doi: 10.1001/jamainternmed.2025.5723. [Online ahead of print].

Katz JN, Collins JE, Wright J, et al. A randomized trial of physical therapy for meniscal tear. N Engl J Med. 2025;393(17):1694-1703.

Chronic knee pain is one of the most common musculoskeletal problems encountered in primary care.¹ Most patients have radiographic or clinical osteoarthritis (OA), while a substantial subset (most often adults in midlife and older) also has degenerative meniscal tears. For decades, treatment pathways have varied widely, often beginning with imaging, medications, and referral to physical therapy (PT) with inconsistent emphasis on behavioral and exercise-based care.^1,2 The RETREAT study and TeMPO, two major randomized clinical trials published in late 2025, provide high-quality evidence clarifying how clinicians should approach interventions that are movement based. Together, these studies reinforce the concept that structured exercise is foundational and that accessible, unsupervised, home-based programs can be highly effective, with suggestive implications for triage, referral patterns, and patient counseling.

RETREAT: Online Unsupervised Tai Chi Improves Pain and Function in Knee OA

The RETREAT trial enrolled 178 adults older than 45 years of age with clinically diagnosed knee OA using recognized criteria. Participants were randomized to either an education website alone or an education website plus a 12-week online, unsupervised Tai Chi program (“My Joint Tai Chi”),supported by a companion adherence app delivering behavior change messaging.³

My Joint Tai Chi consisted of 12 prerecorded 45-minute Yang-style sessions with one new session each week, repeated three times each week. Most participants were female and the average age was early 60s, with significant comorbidity burden typical of OA patients.

At 12 weeks, the Tai Chi group showed significantly greater improvement in all primary outcomes (P < 0.001), including pain during walking, physical functioning, and in measures of clinically meaningful improvement. Secondary outcomes also favored Tai Chi (P < 0.01-0.05) and included measures of quality of life, balance, and mental well-being. Importantly, there were no serious intervention-related adverse complications reported and compliance was high, with more than 82% of the participants reporting completion of at least two sessions a week.

TeMPO: Home Exercise Performs as Well as Supervised PT for Meniscal Tear and Knee OA

The TeMPO trial randomized 879 adults aged 45 to 85 years with degenerative meniscal tears and concurrent knee OA (Kellgren-Lawrence Grades 0-3) to one of four arms:

1. Home exercise alone

2. Home exercise and text message adherence support

3. Home exercise and tech support and sham PT

4. Home exercise and tech support and in-person PT

The home program required 100 minutes per week of lower extremity strengthening and stretching. PT arms included a structured 12-week program with progressive strengthening and manual therapy. Sham PT controlled for therapeutic contact by applying ultrasound at 0 intensity, neutral lotion, and non-therapeutic manual contact.

At three months, all groups improved substantially and none of the primary comparisons showed significant differences. At six months and 12 months, standard PT showed slightly greater improvements compared to each of the other groups, but the improvement was of questionable clinical significance or relevance. Treatment failure, such as lack of improvement, need for injections, or surgery, did not differ significantly across groups. Serious adverse events were rare.

Commentary

The RETREAT and TeMPO trials provide meaningful and complementary insights into the management of chronic knee pain, yet each must be interpreted with careful attention to its context and limitations. Together, they support the central role of exercise in both knee OA and degenerative meniscal tear while also illustrating the growing feasibility of remote and home-based therapeutic approaches.

The RETREAT trial shows that a fully online, unsupervised Tai Chi program can produce clinically significant improvements in pain during walking and physical function over 12 weeks when compared with an education-only control. For primary care providers, this offers an appealing option for patients who cannot access in-person classes or formal physical therapy, either because of geographic constraints, financial barriers, or personal preference. The program used in RETREAT was carefully structured, delivered by an experienced instructor, and supported by a behavior-change app. Importantly, adherence in the Tai Chi group was high, and participants reported strong satisfaction with the program.

Despite these strengths, the RETREAT trial’s limitations must temper how quickly the results are generalized. The study evaluated outcomes after only 12 weeks, leaving the long-term durability of the benefits unknown. The participants were comfortable using online technology and had reliable internet access, which may not reflect the broader population of adults with knee OA. Because the intervention was unsupervised, the quality of movement was not observed. In addition, the accuracy of Tai Chi performance can vary substantially between individuals. Perhaps most importantly, RETREAT compared Tai Chi only to education and not to other active treatments such as strengthening programs, supervised physical therapy, or walking-based exercise. Although the findings indicate that Tai Chi is effective, they do not establish that it is superior to other exercise modalities currently recommended in guidelines. For these reasons, the trial reinforces Tai Chi as a viable and evidence-based option, but not yet as a preferred or guideline-changing intervention.

The TeMPO trial addresses a different but equally common clinical scenario: knee pain in adults with degenerative meniscal tears and coexisting OA. Its central finding is that a structured home exercise program produces improvement in pain and function that were essentially identical to those achieved with motivational text messages or with 12 weeks of supervised, protocol-driven therapy. At three months, the differences between groups were negligible and well below the threshold of clinical importance. Even at six and 12 months, when supervised physical therapy showed slightly greater improvement, the effect sizes remained small.

For primary care clinicians, this study provides reassurance that beginning treatment with a clear, well-defined home exercise program is reasonable and often sufficient. Many patients can achieve meaningful improvement without needing formal physical therapy, which can be expensive, time-consuming, and difficult to access in some regions. The findings also highlight the powerful role of patient engagement and adherence, as participants across all groups exercised regularly and consistently.

Yet, as with RETREAT, the context of TeMPO determines how broadly it should be applied. The participants were recruited from orthopedic and academic centers, and all underwent magnetic resonance imaging, which is not the typical pathway for most primary care patients with knee pain. Adherence to home exercise in TeMPO was unusually high, possibly influenced by the structure and oversight inherent to participating in a clinical trial. This level of adherence is not commonly seen in real-world practice and a drop in adherence outside a study setting may lead to different outcomes. The standardized physical therapy protocol used in the trial, while rigorous and well-described, does not necessarily reflect the variability in quality and technique that exists across community physical therapy practices. The finding that sham therapy performed similarly to standardized therapy suggests that nonspecific therapeutic effects, including attention and support, may contribute significantly to improvement. This is clinically meaningful but complicates the interpretation of physical therapy-specific benefits. Finally, the trial excluded individuals with severe OA, which limits its generalizability to patients with advanced disease who may not respond as well to home exercise alone.

When considering these two studies together, a consistent theme emerges. Exercise, whether delivered through strengthening, stretching, or mind-body programs, remains the cornerstone of care for both osteoarthritis and degenerative meniscal tear. Home-based and digital options can be effective and accessible, and many patients can improve meaningfully without requiring early referral to supervised physical therapy. At the same time, neither trial is comprehensive enough to justify major changes in existing guidelines. The RETREAT trial requires long-term data and comparisons with other exercise modalities, while the TeMPO trial needs confirmation in more diverse primary care populations and in settings where adherence is less tightly controlled.

For clinicians, the practical implication is to continue prescribing exercise confidently as first-line treatment, recognizing that a well-structured home program may be as effective as supervised therapy. Tai Chi can be presented as one validated option among several, especially for patients who prefer a low-impact, holistic approach, although other strengthening-based regimens remain equally important. Physical therapy should remain available and perhaps be considered for individuals who do not improve with home exercise, those who require additional guidance or confidence building, or those with complicating factors such as gait instability or significant functional impairment.

Ultimately, the RETREAT and TeMPO trials enrich the evidence base that supports exercise as an essential component of knee pain management. They also highlight the ongoing need for comparative, long-term, and real-world studies that can clarify the best modes of delivery, the most responsive patient subgroups, and the most effective strategies for sustaining adherence. For now, these trials strengthen existing principles rather than redefine them, while encouraging clinicians to leverage the growing range of accessible, patient-focused exercise options in primary care.

Ellen Feldman, MD, works for Altru Health System, Grand Forks, ND.

References

1. Duong V, Oo WM, Ding C, et al. Evaluation and treatment of knee pain: A review. JAMA. 2023;330:1568-1580.

2. Vanneste T, Belba A, Oei GTML, et al. Chronic knee pain. Pain Pract. 2025;25(1):e13408.

3. My Joint Tai Chi. https://myjoint-taichi.org.