Flexor Tenolysis Technique

Updated: Sep 13, 2021
  • Author: Cato T Laurencin, MD, PhD; Chief Editor: Harris Gellman, MD  more...
  • Print

Approach Considerations

Flexor tenolysis is a surgical procedure used to remove adhesions that inhibit active flexion of digits. Candidates for this procedure typically present with decreased active range of motion (ROM) after surgical repair of flexor tendons. The average time from flexor repair to flexor tenolysis has been indicated to be around 8 months, but the length of this interval varies widely, ranging from 2 to almost 25 months. [4]  Developments in primary tendon repair (eg, stronger core tendon repair techniques, as well as judicious and adequate venting of critical pulleys, followed by a combination of passive and active digital flexion and extension) may lead to lower rates of tenolysis. [20]

A 2012 study looked at a population of New York State dwellers who had flexor tendon reconstruction and found that 6% of patients required a subsequent surgical correction. Tenolysis was performed in 186 (3.6%) of 5229 patients, and tenolysis in combination with tendon re-repair was performed in 11 (0.2%). [10]  In that particular population, patients who underwent concomitant nerve repair during the initial tendon repair were 26% less likely to undergo a reoperation.

Other studies showed that approximately 28% of flexor tendon repairs have a suboptimal recovery period, likely due in large part to tendon adhesions. [21]

Although steroid injections to augment tendon repair are notable in the literature, [19, 22, 23]  they are not universal, and by the time tendon adhesions occur, there is no currently accepted medical therapy to treat the condition. [3]

Various barrier materials have been studied as potential means of preventing postoperative tendon adhesion, including Seprafilm and other hydrogels. [24, 25, 26]

A mini-invasive approach to flexor tenolysis has been described for adhesions in zones 1 and 2. [27]


Surgical Lysis of Flexor Tendon Adhesions

Care must be taken to ensure that the patient meets all indications for surgery to proceed, including a rigorous examination of the external anatomy to check for mature scarring and good passive ROM.

The procedure begins with exposure of the full length of the flexor tendon through either a zigzag or a midlateral incision. A zigzag incision, championed by Schneider, provides the best operative window to the flexor tendon and pulley system. [28, 29] The midlateral incision is believed to diminish the presence of scarring directly over the affected flexor tendon and puts the neural and vascular structures at less risk. [30]

After exposure, both flexor tendons (ie, flexor digitorum profundus [FDP] and flexor digitorum superficialis [FDS]) are raised from underlying structures, and all tendon adhesions are lysed. After adhesions are removed between the tendons and the sheath, it is usually recommended to remove adhesions between the FDP and the FDS, with sacrifice of the FDS being necessary if free tendon gliding cannot be accomplished otherwise. [29]

During the process of removing adhesions, the participation of the patient can be critical, especially when one is trying to differentiate between scar tissue and the pulley system. Although adhesion removal using lasers has been described in rabbits, the practice has not gained a wide clinical following in the human population, and most surgeons still use traditional hand instruments modified for the procedure. [31]

A crucial aspect of flexor tenolysis is to respect the pulley system for the flexor tendons. Preservation of this system, especially the A2 and A4 pulleys, is vital for normal flexor tendon activity. Less commonly, the pulley structures are compromised and a pulley reconstruction may be indicated. [3, 29]  A safer way to reconstruct the pulley system using natural or synthetic materials could potentially improve the prognosis for this procedure. [32]  Usually, the procedure continues and adhesions are removed until full active flexion can be achieved.

The final stage of the surgery is to assess whether the tendon is robust enough to progress through the rigorous physical therapy necessitated by this complex procedure. Both scarring and substantial tendon tissue loss (>30% width lost) can put the patient at risk, and in such situations it is generally recommended that the patient undergo a two-stage tendon reconstruction. [12, 28, 29, 30, 33]

Some physicians treat patients with steroids at this point in order to abrogate the formation of new adhesions during recovery, but given that steroids have a well-described capability to limit the healing response, many abstain from their use altogether.

Since the 1930s, physicians have described the use of various other natural or synthetic materials to prevent subsequent formation of tendon adhesions, [34, 24, 25, 26] but these techniques have not yet been universally accepted.


Postoperative Care

Physical therapy is absolutely necessary for healthy tendon function to return, and poorly controlled pain can hamper the recovery effort. To reduce postoperative pain, most physicians recommend oral analgesia, but every patient is different, and severe cases of pain may necessitate more extreme measures, including indwelling catheters capable of dispensing local anesthesia. [30]

When to start physical therapy in an issue up for debate. As immobilization is necessary for the tendon adhesions to form, some physicians recommend immediate hand exercises, whereas others recommend waiting for a period of days until the effects of the surgical approach (eg, inflammation and scarring) have diminished.

The level and rigor of physical therapy should take the individual surgery of the patient into consideration. If, upon surgical exposure of the flexor tendon, the surgeon notices significant impairment in the health and quality of the tendon, this important information should be relayed to the physical therapist, who may then appropriately modify a treatment plan. Protocols for patients with poor tendon quality are well documented and have shown improved results in comparison with a protocol for a healthier tendon. [35]

A common protocol for patients with a healthy tendon is to undergo physical therapy 3-5 days per week at first and then to decrease the frequency of physical therapy slowly over a period of weeks to months, with the goal of decreasing pain and increasing ROM and strength.



Some studies have shown that as many as 20% of patients who undergo this procedure do not benefit from the operation; 8% of patients experience frank tendon rupture, with some studies reporting rates as high as 15%. [10, 35, 36]

Although flexor tenolysis has proved to be effective in the majority of cases, the complication rate is still very high, and much research is needed into protocols, surgical techniques, or materials that can restore active ROM to patients.

One way to combat the formation of adhesions after flexor tendon repair would be to find a therapy that could decrease the immunologic response to the surgery. [37, 38]  As mentioned before, corticosteroids have been tried, but their limitations are too severe for widespread acceptance.