Core stabilization added measurable benefit in knee osteoarthritis rehabilitation
A 12-week randomized controlled trial in adults with mild-to-moderate knee osteoarthritis found that adding a structured core program to conventional knee-focused rehabilitation improved pain and function more than standard care alone. The intervention, CARE-KOA©, was tested in 100 participants with Kellgren–Lawrence grade 1–3 disease, a population in which symptoms often track with movement intolerance long before end-stage structural failure enters the picture.
The design was assessor-blinded and single-center, with participants randomized to either CARE-KOA rehabilitation or conventional knee-based rehabilitation. Outcomes were tracked at baseline and again at 4, 8, and 12 weeks, allowing investigators to observe whether the added trunk-focused work translated into changes that patients would actually feel in daily life. Pain, patient-reported outcomes, transitional physical function, isometric knee strength, and core endurance all sat at the center of the analysis.
The clearest signal emerged in activity-related pain. After adjustment for baseline imbalances, the CARE-KOA arm achieved a between-group difference of −2.27 cm on VAS-Activity (95% CI −2.65 to −1.88), a margin large enough to matter in the clinic because activity pain is what drives avoidance, deconditioning, and the downward spiral of osteoarthritis-related disability. On the function side, the intervention group also improved more on the KOOS-ADL, with an adjusted between-group difference of 5.45 points (95% CI 2.62 to 8.28). Transitional mobility improved as well: the Timed Up-and-Go favored CARE-KOA by 5.49 seconds (95% CI −6.16 to −4.81).
Why trunk control may matter as much as the knee itself
Knee osteoarthritis is not confined to the joint surface. Pain alters gait, shifts load distribution, and reduces the body’s ability to absorb force smoothly through the kinetic chain. In that setting, weak or poorly coordinated trunk musculature can amplify mechanical stress at the knee, especially during walking, stair climbing, and sit-to-stand transfers. A core program can plausibly improve lumbopelvic control, reduce compensatory movement patterns, and make lower-limb rehabilitation more efficient.
The trial’s results fit that physiology. Participants receiving the added core intervention improved in core endurance, while isometric knee muscle strength improved to a similar degree in both groups. That split is important. It suggests the added benefit did not come from a generalized strengthening effect across all muscle groups, but from a more targeted change in trunk stability and movement efficiency that carried over into pain and functional performance.
One sentence captures the whole pattern: the knee got stronger in both groups, but the patients with core training moved better and hurt less.
Pain relief came with functional gains, not just isolated test scores
The strongest practical value of this trial lies in the alignment between patient-reported outcomes and objective mobility. A smaller pain score means little if daily movement remains limited; here, the improvement in activity pain was accompanied by better KOOS-ADL scores and a faster Timed Up-and-Go. In rehabilitation research, that combination matters because it suggests the intervention altered not only symptom reporting but also real-world movement capacity.
The baseline imbalances in VAS-Activity, KOOS-ADL, and TUG were handled with analysis of covariance, preserving the interpretability of the adjusted comparisons. Even after that correction, the between-group differences remained statistically significant for the primary functional signals. For clinicians, the message is straightforward: when core stabilization is layered onto conventional knee rehabilitation, the patient may gain more from the same rehabilitation window than with knee work alone.
This matters in a condition where treatment success is often judged by whether a patient can climb stairs, rise from a chair, or walk without guarding every step. The TUG result is particularly relevant because it reflects transitional mobility rather than isolated strength on a testing table. Rehabilitation gains that show up in transition tasks are often the ones patients notice first.
Isometric strength did not separate the groups
Not every endpoint moved in the same direction. Isometric knee muscle strength improved, but the gains were comparable between CARE-KOA and conventional rehabilitation. That finding tempers any claim that trunk training is a substitute for knee-centric strengthening. The better interpretation is additive rather than replacement: core stabilization appears to complement conventional therapy by improving the control system around the knee, while knee strengthening continues to address the local musculature directly.
This distinction matters for program design. A therapist can reasonably keep conventional lower-limb rehabilitation at the center of care while adding structured trunk work to improve tolerance, coordination, and function. The data do not support a wholesale pivot away from knee strengthening; they support a broader rehabilitation frame that includes the trunk as a load-sharing structure.
The trial’s scope is useful, but still bounded
The study enrolled 100 participants, all with mild-to-moderate osteoarthritis, and followed them for 12 weeks. That makes the findings clinically relevant for early to intermediate disease, but it also narrows what can be claimed. Severe osteoarthritis, longer-term durability, and broader implementation in different care settings remain outside the observed data. Single-center rehabilitation trials can also reflect local expertise, therapist skill, and adherence patterns that do not translate perfectly across clinics.
Even so, the structured design strengthens confidence in the signal. The trial was prospectively registered in the Clinical Trials Registry of India under CTRI/2023/07/054805, and the blinded outcome assessment reduces the risk that expectation alone drove the differences. The authors also reported no competing interests and no external funding from agencies or commercial sectors, which helps frame the work as an investigator-led rehabilitation study rather than a device- or industry-driven experiment.
The practical takeaway is not that core exercises replace knee rehabilitation. It is that trunk training can add measurable value when the goal is to reduce activity pain and restore daily function in knee osteoarthritis.
For patients with mild-to-moderate disease, the next question is no longer whether the knee matters. It is how much more function can be recovered when the core is treated as part of the same biomechanical problem.