What are the best ways for recovering movement in the hand after surgery to repair flexor tendons (tendons in the hand that enable fingers to bend)?

Why is this question important?

Flexor tendons are strong smooth cords that connect the muscles in the forearm (between the hand and elbow) to the bones in the fingers. These tendons allow us to bend our fingers. (Other tendons, known as extensor tendons, allow us to straighten them.)

If flexor tendons become damaged – for example, because of a deep cut from broken glass – surgery is usually needed. The aim of surgery is to repair the tendons so that movement can be restored in the affected fingers.

After surgery, the tendons need a lengthy period of rehabilitation to recover from the injury, the surgery and to restore movement. This period typically lasts 12 weeks, though it can be longer for people with complex injuries or with complications such as joint deformities. Rehabilitation usually involves several different steps. After surgery, people often must wear a splint or other devise to stabilise or immobilise the hand and wrist. They also often must do hand exercises to stop the repaired tendons from sticking to surrounding tissue and limiting hand movement.

There are many kinds of different rehabilitation programmes, but it is unclear whether some are better than others. We set out to review the evidence from research studies, to find out:

- which approaches are most effective in restoring finger motion and function; and

- which approaches minimise the risk of adverse (unwanted) events, such as tendon ruptures, scar tissue sticking to other tissues, and joint stiffness.

How did we identify and evaluate the evidence?

First, we searched for studies in the medical literature that compared any rehabilitation approach after flexor tendon surgery against:

- no treatment;

- a placebo (dummy) treatment (in which, for example, someone thinks they may be receiving laser therapy but the machine is switched off); or

- another rehabilitation approach.

We then compared the results, and summarised the evidence from all the studies. Finally, we rated our confidence in the evidence, based on factors such as study methods and sizes, and the consistency of findings across studies that tested the same comparison.

What did we find?

We found 17 studies that involved a total of 1108 people who had received surgery to repair torn flexor tendons. The people were aged between 7 and 72 years, and three-quarters of them were male.

Ten studies evaluated one each of eight different hand exercise programmes. The other seven studies evaluated a variety of other rehabilitation approaches, such as:

- laser therapy, in which light is directed at the tendons to encourage healing;

- ultrasound, in which sound waves are directed at the tendons to encourage healing; and

- a wearable machine (exoskeleton), designed to assist people in their movements.

We found very little evidence about the benefits and risks of different rehabilitation approaches. The evidence we did find was not robust. For example, for the three most relevant exercise comparisons we identified only:

- one study (84 people) that compared finger exercises against immobilisation;

- one study (53 people) that evaluated the effects of adding regular finger exercises (20 to 30 times every waking hour for four weeks from the first day after surgery) to ‘passive’ exercises (in which people regularly folded the fingers in the injured hand using the uninjured hand); and

- three studies (190 people) that evaluated the effects of adding ‘place and hold’ exercises (during which people use their uninjured hand to fold the fingers of the injured hand, and then have to hold the folded fingers in place for a few seconds without any support) to passive exercises.

The studies were too small, or reported too little robust or usable information, for us to determine which approach is best.

What does this mean?

We do not know which method works best for people to recover movement in the hand after surgery to repair flexor tendons. This is because there is not enough robust evidence about the benefits and risks of different methods.

Further research is needed to help inform clinicians’ and patients’ choice of rehabilitation after surgery for flexor tendon injuries.

How up-to-date is this review?

The evidence in this Cochrane Review is current to August 2020.

Authors' conclusions: 

There is a lack of evidence from RCTs on most of the rehabilitation interventions used following surgery for flexor tendon injuries of the hand. The limited and very low-certainty evidence for all 14 comparisons examined in the 17 included studies means that we have very little confidence in the estimates of effect for all outcomes for which data were available for these comparisons.

The dearth of evidence identified in this review points to the urgent need for sufficiently powered RCTs that examine key questions relating to the rehabilitation of these injuries. A consensus approach identifying these and establishing minimum study conduct and reporting criteria will be valuable. Our suggestions for future research are detailed in the review.

Read the full abstract...

Various rehabilitation treatments may be offered following surgery for flexor tendon injuries of the hand. Rehabilitation often includes a combination of an exercise regimen and an orthosis, plus other rehabilitation treatments, usually delivered together. The effectiveness of these interventions remains unclear.


To assess the effects (benefits and harms) of different rehabilitation interventions after surgery for flexor tendon injuries of the hand.

Search strategy: 

We searched the Cochrane Central Register of Controlled Trials, the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, MEDLINE, Embase, two additional databases and two international trials registries, unrestricted by language. The last date of searches was 11 August 2020. We checked the reference lists of included studies and relevant systematic reviews.

Selection criteria: 

We included randomised controlled trials (RCTs) and quasi-RCTs that compared any postoperative rehabilitation intervention with no intervention, control, placebo, or another postoperative rehabilitation intervention in individuals who have had surgery for flexor tendon injuries of the hand. Trials comparing different mobilisation regimens either with another mobilisation regimen or with a control were the main comparisons of interest. Our main outcomes of interest were patient-reported function, active range of motion of the fingers, and number of participants experiencing an adverse event.

Data collection and analysis: 

Two review authors independently selected trials for inclusion, extracted data, assessed risk of bias and assessed the quality of the body of evidence for primary outcomes using the GRADE approach, according to standard Cochrane methodology.

Main results: 

We included 16 RCTs and one quasi-RCT, with a total of 1108 participants, mainly adults. Overall, the participants were aged between 7 and 72 years, and 74% were male. Studies mainly focused on flexor tendon injuries in zone II.

The 17 studies were heterogeneous with respect to the types of rehabilitation treatments provided, intensity, duration of treatment and the treatment setting. Each trial tested one of 14 comparisons, eight of which were of different exercise regimens. The other trials examined the timing of return to unrestricted functional activities after surgery (one study); the use of external devices applied to the participant to facilitate mobilisation, such as an exoskeleton (one study) or continuous passive motion device (one study); modalities such as laser therapy (two studies) or ultrasound therapy (one study); and a motor imagery treatment (one study). No trials tested different types of orthoses; different orthosis wearing regimens, including duration; different timings for commencing mobilisation; different types of scar management; or different timings for commencing strengthening.

Trials were generally at high risk of bias for one or more domains, including lack of blinding, incomplete outcome data and selective outcome reporting. Data pooling was limited to tendon rupture data in a three trial comparison. We rated the evidence available for all reported outcomes of all comparisons as very low-certainty evidence, which means that we have very little confidence in the estimates of effect.

We present the findings from three exercise regimen comparisons, as these are commonly used in clinical current practice.

Early active flexion plus controlled passive exercise regimen versus early controlled passive exercise regimen (modified Kleinert protocol) was compared in one trial of 53 participants with mainly zone II flexor tendon repairs. There is very low-certainty evidence of no clinically important difference between the two groups in patient-rated function or active finger range of motion at 6 or 12 months follow-up. There is very low-certainty evidence of little between-group difference in adverse events: there were 15 overall. All three tendon ruptures underwent secondary surgery.

An active exercise regimen versus an immobilisation regimen for three weeks was compared in one trial reporting data for 84 participants with zone II flexor tendon repairs. The trial did not report on self-rated function, on range of movement during three to six months or numbers of participants experiencing adverse events. The very low-certainty evidence for poor (under one-quarter that of normal) range of finger movement at one to three years follow-up means we are uncertain of the finding of zero cases in the active group versus seven cases in the immobilisation regimen. The same uncertainty applies to the finding of little difference between the two groups in adverse events (5 tendon ruptures in the active group versus 10 probable scar adhesion in the immobilisation group) indicated for surgery.

Place and hold exercise regimen performed within an orthosis versus a controlled passive regimen using rubber band traction was compared in three heterogeneous trials, which reported data for a maximum of 194 participants, with mainly zone II flexor tendon repairs. The trials did not report on range of movement during three to six months, or numbers of participants experiencing adverse events. There was very low-certainty evidence of no difference in self-rated function using the Disability of the Arm, Shoulder and Hand (DASH) functional assessment between the two groups at six months (one trial) or at 12 months (one trial). There is very low-certainty evidence from one trial of greater active finger range of motion at 12 months after place and hold. Secondary surgery data were not available; however, all seven recorded tendon ruptures would have required surgery.

All the evidence for the other five exercise comparisons as well as those of the other six comparisons made by the included studies was incomplete and, where available, of very low-certainty.