In thumb carpometacarpal (CMC) osteoarthritis, attention quickly turns to pain, loss of strength, and restricted movement. This is understandable, but it may not tell the whole story. The thumb CMC joint must not only be able to withstand load; it must also continuously sense and control its position.
This is where proprioception comes into play. It describes the ability to perceive the position and movement of a joint without constantly having to look at it. For the thumb, this feedback is particularly important because even small changes in joint position can determine whether a grip is performed in a stable and precise manner.
A systematic review published in the Journal of Hand Therapy in 2026 brings this previously underrecognized aspect of thumb CMC osteoarthritis into greater focus. Eapen and colleagues (2026) evaluated five randomized controlled trials involving a total of 260 participants and investigated whether proprioceptive training provides measurable additional benefits when combined with conventional rehabilitation.
When Strength Alone Does Not Explain Everything
In everyday practice, it often becomes apparent that a thumb may not simply be “too weak.” Some patients, for example, have sufficient strength to hold an object but are unable to control the position of the thumb precisely under load. This can become noticeable when opening a screw-top lid, performing a key pinch, or making precise contact between the thumb and fingertips.
This ability depends on a continuous exchange of information between peripheral receptors and the central nervous system. Information from joints, muscles, tendons, and the skin helps the body adjust movements.
In thumb CMC osteoarthritis, this feedback may be impaired. The systematic review described above identifies proprioceptive deficits as a factor that may contribute to joint instability and functional limitations. Rather than speaking of a “loss” of proprioception, it is therefore more accurate to assume that the precision of joint position sense may be reduced.
What Did the New Systematic Review Investigate?
Eapen and colleagues (2026) searched seven scientific databases for randomized controlled trials on thumb CMC osteoarthritis. The review included studies comparing conventional rehabilitation—for example strengthening, orthotic management, or activity modification—with programs that additionally incorporated proprioceptive exercises.
Five studies met the inclusion criteria, comprising a total of 260 participants. Methodological quality ranged from 6 to 8 out of 10 points on the PEDro scale.[1] Outcomes included pain, hand function, joint position sense, and grip and pinch strength.
Overall, the results favored the addition of proprioceptive training.
The clearest difference was found for joint position sense. In all five studies, the error when reproducing a joint position decreased. The pooled effect was comparatively large, with a standardized mean difference (SMD) of −1.2.
Benefits were also observed for Hand function . In studies using the QuickDASH[2] or COPM[3], the pooled effect was SMD −0.7. For grip and pinch strength , four studies reported an effect of SMD 0.8.
The findings for pain were less consistent. Three of the five studies showed benefits in favor of proprioceptive training, and in two of these the respective threshold for a clinically meaningful change was also exceeded. The pooled effect was SMD −0.6.
Particularly Interesting: The Early Stages
One notable finding was that the greatest benefits were observed in patients with thumb CMC osteoarthritis in Eaton-Littler stages I and II.
This is therapeutically interesting, but it should not be overinterpreted. The findings do not mean that proprioceptive training can prevent the progression of osteoarthritis or reliably prevent the later development of chronic pain.
Rather, they suggest that sensorimotor control may be a particularly relevant therapeutic target in the early stages of the condition.
Especially when structural changes are still relatively limited, it may be useful to incorporate precise control of the thumb into the treatment concept at an early stage, alongside strengthening, joint protection, and mobility exercises.
What Does Proprioceptive Training Actually Mean?
The term proprioceptive training is sometimes used rather loosely. It does not simply refer to any exercise in which the thumb is moved.
The focus is on the ability to perceive and control joint position and movement as accurately as possible.
A classic task, for example, is joint position reproduction. The thumb is first placed in a specific position. The patient is then asked to reproduce that position, potentially without visual feedback.
Other exercises involve small, controlled external disturbances. The thumb is required to maintain a predetermined position while varying light resistance is applied from the outside. Goal-directed movements and controlled changes in loading may also form part of this type of training.
The key difference compared with conventional strength training is that the aim is not to generate as much force as possible. Instead, the goal is to control a movement or joint position as precisely as possible..
Practical Example: Finding a Thumb Position Without Looking
A simple exercise illustrates the principle well. It is based on active joint position reproduction tasks used in clinical studies.
The patient rests the hand comfortably or holds it in a relaxed starting position. The thumb is then slowly guided into a predetermined position—for example, a specific degree of abduction.
This position is initially perceived consciously with the eyes open for several seconds:
Where is the thumb positioned? How far is it from the palm? What does this position feel like?
The thumb then returns to the starting position.
The eyes are then closed. The task is to move the thumb as accurately as possible back into the previously perceived position. Only once the position has been reached are the eyes opened and the result checked.
One variation used in one of the investigated training programs involved several marked target positions. Patients first moved their thumb to different points with visual feedback and then repeated the task without looking.
The training stimulus is therefore not about moving as far or as forcefully as possible. The crucial question is:
How accurately can I reproduce a previously perceived position?
Deviations are not “mistakes” in the traditional sense. Instead, they provide feedback that can be used during the next repetition.
Initially, this type of exercise should be introduced under therapeutic guidance and adapted to the individual joint condition. Painful end-range positions or positions that provoke unfavorable joint alignment are not the goal.
Strength and Proprioception Are Not Opposites
At first glance, it may seem surprising that grip and pinch strength also improved in the systematic review. After all, proprioceptive training was not primarily designed as strength training.
One possible explanation lies in neuromuscular control. Strength can only be used functionally when the muscles involved are activated at the right time and with an appropriate level of force. More precise joint control could therefore help patients use their existing strength more effectively.
However, the available studies do not allow firm conclusions beyond this. The systematic review demonstrates improved strength values following additional proprioceptive training, but it does not conclusively explain the mechanisms responsible for these improvements.
For the same reason, it would be too simplistic to single out individual muscles as the “bodyguards of the thumb” and attribute the effects of training to them. Stability of the CMC-I joint results from the interaction between joint geometry, capsuloligamentous structures, muscles, and sensory feedback.
Does the Training Need to Be Supervised by a Therapist?
The included studies differed in their training protocols, meaning that no standardized program can currently be recommended. The systematic review also emphasizes the need for future studies using more consistent protocols and longer follow-up periods.
From a practical perspective, it may be useful to introduce proprioceptive exercises under therapeutic supervision. When training joint position sense, the aim is not to complete as many repetitions as possible. Quality is what matters. Unnoticed compensatory movements, excessive loading, or unfavorable joint positioning can alter the intended training stimulus.
Therapeutic feedback can therefore help establish precise movement patterns initially. Many exercises can later be incorporated into a home exercise program.
However, the current evidence does not yet provide a universally applicable answer regarding how often or for how long proprioceptive training should be performed.
The New Systematic Review Is Not the Final Word
Despite the positive findings reported in 2026, it is also worth considering a larger systematic review published by Koumantakis and colleagues in 2024.
This meta-analysis examined nine randomized controlled trials of proprioceptive exercises involving a total of 750 participants. Compared with standard treatment, benefits for pain and especially functional limitations were observed in the very short term. At medium- and longer-term follow-up, however, significant differences were no longer detectable.
This puts the more recent findings into perspective.
The systematic review by Eapen and colleagues (2026) had a more specific focus and included five RCTs that met its narrower criteria. Its findings support considering proprioceptive training as an adjunct to conservative treatment. At the same time, the authors emphasize that larger studies are needed and that it remains particularly important to determine whether the effects persist beyond three months. über drei Monate hinaus bestehen bleiben.
For hand therapy, this is an important distinction: there are now good reasons to take proprioception seriously. However, there is currently no evidence that one particular exercise program is superior to all other approaches in the long term.
What Can We Take Away for Treatment?
The new evidence points less toward an entirely new form of therapy and more toward broadening our existing perspective on thumb CMC osteoarthritis.
Orthoses, joint protection, load modification, strength training, and functional exercises all retain their importance. Proprioceptive training can complement these measures.
Particularly in the early stages, assessment may benefit from looking beyond pain, mobility, and strength. The question of how precisely a patient can position the thumb and control it under load also deserves attention.
This shifts the therapeutic focus slightly: not only “How strong is the thumb?”, but also “How well can it be controlled?”
[1] PEDro Scale: An assessment tool used to evaluate the methodological quality of randomized clinical trials in physiotherapy. The scale consists of 11 criteria, 10 of which contribute to the total score. The resulting PEDro score ranges from 0 to 10 points.
[2] Kurzversion des Disabilities of the Arm, Shoulder and Hand (DASH)[2] QuickDASH: The shortened version of the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, consisting of 11 questions. It assesses self-reported limitations and symptoms affecting the upper extremity; higher scores indicate greater impairment.
[3] COPM: The Canadian Occupational Performance Measure is a client-centered assessment used to identify individually meaningful occupational performance problems. Patients rate their perceived performance and satisfaction on a scale from 1 to 10. Canadian Occupational Performance Measure ist ein klientenzentriertes Assessment zur Erfassung individuell bedeutsamer Betätigungsprobleme. Die Betroffenen bewerten ihre wahrgenommene Ausführungsqualität (Performance) und Zufriedenheit auf einer Skala von 1 bis 10.
Literaturverzeichnis:
Eapen C, Aggarwal V, Thomas DT, Fondekar AP, Godia R. Effectiveness of proprioceptive training in patients with thumb carpometacarpal osteoarthritis: A systematic review. Journal of Hand Therapy. 2026;39(2):459–468. DOI: 10.1016/j.jht.2026.02.015.
Koumantakis GA et al. Exercise-Based Interventions Are Effective in the Management of Patients with Thumb Carpometacarpal Osteoarthritis: A Systematic Review and Meta-Analysis of Randomised Controlled Trials. Healthcare. 2024;12(8):823. DOI: 10.3390/healthcare12080823.
The IHHC Editorial Team is responsible for creating, reviewing, and continuously updating the content published by the International Hand Health Community (IHHC). Its mission is to present current knowledge from hand therapy, occupational therapy, physiotherapy, rehabilitation, and medicine in a way that is evidence-based, practical, and easy to understand.