Flexor Tendon Injuries of the Hand: Causes, Symptoms & Treatment

Flexor tendon injuries to the hand severely limit the mobility and gripping ability of the fingers. Despite the anatomic peculiarities and severity of the limitations, there are now effective therapeutic procedures that usually lead to full recovery of function in the affected fingers.

What are flexor tendon injuries of the hand?

Flexor tendon injuries to the hand are very problematic because the range of motion of the fingers is severely affected. There are two flexor tendons on each individual finger, a superficial and a deep flexor tendon. They represent the connection between the finger and the flexor muscles of the forearm. The superficial flexor tendons are responsible for flexion of the middle finger joint. The deep flexor tendons primarily flex the joints at the upper end of the fingers. However, they also participate in the flexion of the middle and lower finger joints. Each flexor tendon is sheathed by a tendon sheath, which is further reinforced by cruciate and annular ligaments. The ligaments ensure that the tendons are guided tightly along joints and bones. Because of these delicate and special anatomical conditions, flexor tendon injuries of the hand are often complicated.

Causes

Any injury to the flexor side of a finger can result in a flexor tendon injury. This is true for both injuries with and without skin breakdown. Often, puncture wounds and cuts, such as those that can be inflicted by knives, cut open food cans, or broken glass, result in severing of the flexor tendons. Severe crush injuries as well as blunt force trauma can also cause flexor tendon injuries. People who work on machines with sharp cutting surfaces, such as grinders and circular saws, are also at high risk for such injuries. Animal bites are another cause. Generally, rather strong force is required to sever the relatively strong flexor tendons, which are about five to ten millimeters in diameter.

Symptoms, complaints, and signs

The flexor tendon in the hand can be injured by a variety of causes, and the symptoms and signs vary just as much. However, each type of injury triggers severe pain and can result in anything from limited motion to almost complete immobility of the hand. Injuries caused by external events are usually actively witnessed and recognized by the patient. These may be cuts, bruises, contusions, or tendon strain due to sprain, in either case a specific event is the cause. In the case of open injuries, more or less severe bleeding may occur. Injuries that are often not visible from the outside are attachments or detachments of the flexor tendon due to external impulses. In these cases, pain is immediate and severe, with onset of injury. Other injuries to the flexor tendon in the hand occur as a result of prolonged overuse, for example during unaccustomed physical work, long periods of housework or during sports. In these cases, the symptoms often become apparent over a longer period of time, but are ignored in the early stages. A mostly dull, only in rare cases stabbing pain becomes noticeable. Due to the overload of the flexor tendon, the strength in the hand decreases, a fatigue symptom in addition to the pain becomes noticeable. Often, this also affects the gripping ability and grip strength of the fingers.

Diagnosis and progression

Normally, the fingers have a natural, slightly flexed position when the hand is held in a relaxed position. In contrast, with a flexor tendon injury to the hand, the fingers are extended in an unnaturally stiff position. Bruising and swelling often develop. If the deep flexor tendon is severed, the end joint of the corresponding finger cannot be flexed or can only be flexed with great difficulty. If the superficial and deep flexor tendons are severed at the same time, flexion of the middle joint is difficult or impossible. In addition to flexion function, blood flow and finger sensation are checked during diagnosis for evidence of vascular and nerve injury. In the case of very complex flexor tendon injuries, an x-ray is also taken to identify any bone injuries or hidden foreign bodies.

Complications

Flexor tendon injuries to the hand leave the patient relatively limited in his or her daily life and actions.The restrictions relate primarily to the ability to grasp and to the mobility of the hand and the individual fingers. This means, for example, that normal food intake is no longer possible, so that the affected person is dependent on the help of other people in his or her everyday life. In most cases, flexor tendon injuries of the hand also cause severe pain. The pain not infrequently leads to depression and other psychological complaints. The hand may swell and the pain may also be in the form of pain at rest. As a rule, surgical treatment is performed. The earlier the treatment is started, the better the chances of complete recovery without complications. Usually, after flexor tendon injuries to the hand, the patient cannot immediately put weight on the hand and must wait for a certain period of time until full weight-bearing capacity is restored. This period can be up to six months. After that, there are no further complications or complaints. The fingers can also be loaded again without further ado afterwards.

When should you see a doctor?

In the case of flexor tendon injuries to the hand, a doctor must be consulted immediately. There is no self-healing in this disease, so participation in various therapies is essential for the patient in Regle. Likewise, further complications and possibly paralysis can be avoided. The doctor should be consulted for flexor tendon injuries to the hand if the fingers themselves have an unnatural position or orientation, even if they are extended. As a rule, the affected person can hardly or no longer stretch and bend his fingers, so that there are considerable restrictions in everyday life. Hand pain can also occur with flexor tendon injuries to the hand. Furthermore, swelling and bruising may also be indicative of this condition and should be examined by a medical professional. In acute emergencies or severe pain, the hospital should be visited. The earlier flexor tendon injuries to the hand are detected, the better the prospects for complete recovery. As a rule, however, a doctor should not be consulted for more than 48 hours after the injury, since it is usually not possible to stitch the tendons together after that.

Treatment and therapy

In the case of a flexor tendon injury to the hand, the severed tendons are sutured together as soon as possible. Treatment should be given no later than 48 hours after the injury. The best chance of recovery is if the tendon stumps are reunited within six hours of severing. Muscle pull can cause the tendon ends to slide back into the forearm area, which is why incisions sometimes need to be made in the palm or wrist to find them. If the flexor tendon injury to the hand is infected or older, direct sutures are usually not placed. Instead, a silicone pin is first placed in the tissue to prevent the tendon sheath from sticking. This is followed by a second procedure in which the tendon is sutured together. A tendon graft may also be necessary. The freshly sutured tendon is not yet fully loadable again. The injured finger should only be moved carefully, otherwise there is a risk of the tendon sheath sticking together and the finger becoming stiff. The Kleinert splint, which was specially developed for optimal aftercare, ensures that the patient can actively and powerfully stretch the injured finger, but only powerlessly and passively bend it. Rubber bands between the fingernail and the carpus ensure that the finger can be stretched but not completely. The splint can be removed about six weeks after the procedure, and the finger can then be fully straightened after about twelve weeks.

Outlook and prognosis

In most cases, a flexor tendon injury to the hand heals completely within a few months after surgery. Therefore, the patient has a good chance of being permanently free of symptoms. Approximately 6 weeks after a surgical procedure, the splint inserted on the hand is removed. Immediately afterwards, partial weight-bearing on the hand is already possible. As the self-healing process continues, the hand’s ability to bear weight steadily increases and the patient’s sense of well-being improves. After 12 weeks, the hand can normally be fully used again. However, excessive exertion should be avoided to prevent a relapse.Some patients complain of long-term symptoms such as weather sensitivity or discomfort from the scar on the hand. Full weight-bearing of the hand may take a longer time under certain circumstances. This depends on the age of the patient and the individual regeneration possibilities of the body. Nevertheless, there are good prospects of recovery overall. A prognosis is less optimistic in the case of severing or crushing of the flexor tendons. Complications and thus changes in the healing process can also occur if the injury is treated late or if further damage to the bones was detected too late. In these cases, the hand may be permanently impaired or the healing process may be significantly prolonged by several months.

Prevention

There are no specific measures to prevent flexor tendon injuries to the hand. Extreme caution should always be used when handling sharp objects and machines, as well as animals that have sharp teeth. Individuals who place a high value on fully functional fingers, such as pianists, should try to avoid dangerous machines and objects. But because the chances of recovery from flexor tendon injuries to the hand are generally very good, even piano players can usually eventually resume their activities unimpaired.

Aftercare

Aftercare following flexor tendon injuries to the hand are necessary for several reasons. One is to restore mobility as early as possible by preventing adhesions to the tissues through appropriate exercises. On the other hand, however, too much strain must be avoided so that the injury does not rupture again. For the contrast between flexibility and sparing, the judgment of treating therapists and physicians is decisive, especially in the beginning. Surgeons and movement therapists decide on the current load-bearing capacity of the tissue after flexor tendon injuries to the hand. Often, an individualized therapy plan is created as part of the follow-up care. The therapy exercises are shown to the patient by the therapist and are often performed with the therapist’s help in the beginning. The patient can then practice at home and gradually improve mobility and load-bearing capacity of the structures. In cases of severe flexor tendon injuries to the hand, the occupational therapist can also help restore routine in everyday movements. Follow-up care also includes minimizing the risk of infection after surgery for flexor tendon injuries to the hand. This includes protecting the wound from contamination. Immobilization after surgery is also mandatory until the surgeon releases the possible movements. In the case of redness, throbbing or swelling as classic signs of inflammation, a doctor should be consulted early to examine the wound.

What you can do yourself

The chances of complete healing are highest for an injury to the flexor tendon if severed tendon stumps are reunited immediately, but no later than two days after the injury. Thus, the most important self-help measure is to take seriously an injury to the hand that limits the mobility of the fingers and seek immediate medical attention or hospitalization. After a surgical intervention, the restored tendon cannot be fully loaded immediately. It is imperative that the patient rest the affected hand. Otherwise, there is a risk that the tendon sheath will become stuck and the limb will stiffen. If the attending physician prescribes a Kleinert splint, it must be worn without fail. Here it is extremely important that the patient exercises patience. The splint is usually removed after six weeks at the earliest. After that, it usually takes another one and a half to two months before the tendon can be fully loaded again and the hand can be used as before the injury. Physical therapy exercises can help speed healing and restore full function to the affected fingers.