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ED Treatment of Flexor Tendon Injuries

Roberts, James R. MD

doi: 10.1097/01.EEM.0000410106.40227.cc
InFocus
After local anesthesia, the wound was explored, and to the great surprise of the clinician, the flexor tendon was visualized in the base of the wound. This was unexpected given the superficial appearance. When examined with the fingers in extension, the tendon was unscathed.

After local anesthesia, the wound was explored, and to the great surprise of the clinician, the flexor tendon was visualized in the base of the wound. This was unexpected given the superficial appearance. When examined with the fingers in extension, the tendon was unscathed.

The initial evaluation of hand injuries needs a strong dose of paranoia to suspect and spot flexor tendon injuries. Few clinicians would miss a completely lacerated flexor tendon, assuming that tendon function was adequately evaluated, but a major partial tendon injury, often initially clandestine in the depths of a swollen, bloody, and tender laceration, can mislead even a hand surgeon on the first examination. Fortunately, the emergency physician's mandate is infinitely easier than that of the hand surgeon who has to deal with delayed care, reconstruction, finicky tendon function, patient compliance, and the rigors of hand rehabilitation.

In short, a quintessential respect for the potential for disaster of even a minor hand wound and overcautious ED treatment are your best tactics. Most patients crave such personal attention, a rare commodity these days. Examine to the point of annoyance to bring home the fact that you are-careful, conscientious, and prudent. If you tell the patient there may be a tendon injury and you treat for such, and you are wrong, so what? If a subsequent subtle injury is found on follow-up, you were clairvoyant.

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Inconsistency and Uncertainty

The prescient and sagacious clinician will be well served to overdiagnose partial flexor tendon and nerve injuries. If there is a deep puncture or laceration of the hand and nothing abnormal is ascertained with a careful and prudent examination, no one can be expected to have special powers to visualize the anatomy with certainty. You are left with two choices of what to say to the patient: “Looks OK to me. Change the bandage, and have the sutures out in seven to 10 days,” or “This laceration is deep, and may have injured a nerve or tendon. Even though it seems OK now, I am going to treat you as if there is a significant injury. And here is what you should do to get the definitive answer.”

There is no shame in telling the patient you can't be certain of the exact pathology, if any, at that moment in time. But tell the patient that you or a colleague will certainly attempt to find out, but he must fully understand your concern, and cooperate with the hassles of follow-up and inconvenient splints for a few days.

This patient sustained a rather benign-looking palm laceration from the sharp lid of a cat food can. The mere location makes this wound fair game for a flexor tendon injury. The patient had full active/passive range of motion, no numbness, no pain on flexion, and no weakness when flexing against resistance — all standard criteria for the absence of tendon pathology. The plan was to provide optimal wound cleaning and then, just to be super-safe, splint until a follow-up visit in three to four days. Some might say this plan is too conservative, and the patient, a computer programmer, initially resisted a bulky splint.

This patient sustained a rather benign-looking palm laceration from the sharp lid of a cat food can. The mere location makes this wound fair game for a flexor tendon injury. The patient had full active/passive range of motion, no numbness, no pain on flexion, and no weakness when flexing against resistance — all standard criteria for the absence of tendon pathology. The plan was to provide optimal wound cleaning and then, just to be super-safe, splint until a follow-up visit in three to four days. Some might say this plan is too conservative, and the patient, a computer programmer, initially resisted a bulky splint.

This is a classic phenomenon that should be known to all clinicians. When the index finger was passively flexed by the examiner, the more distal portion of the tendon came into view in the laceration, and a 50-60 percent tendon laceration was seen. When questioned, the patient then said the cut occurred with the fingers in flexion. The clinician's history had been inadequate and hurried.

This is a classic phenomenon that should be known to all clinicians. When the index finger was passively flexed by the examiner, the more distal portion of the tendon came into view in the laceration, and a 50-60 percent tendon laceration was seen. When questioned, the patient then said the cut occurred with the fingers in flexion. The clinician's history had been inadequate and hurried.

A hand surgeon was consulted and advised further cleaning, a few days of antibiotics, and rigid splinting. An outrigger aluminum splint, sandwiched between layers of a short-arm fiberglass splint, kept the tendon immobile until a wound check five days later. All was well, and the splinting was continued for three more weeks. The patient made a full and uneventful recovery without reopening the laceration or suturing the tendon. The partial laceration could have been converted into a full rupture if not recognized and had proper inspection and precautions not been taken. It pays to be paranoid; you just cannot go wrong by overdiagnosing such injuries.

A hand surgeon was consulted and advised further cleaning, a few days of antibiotics, and rigid splinting. An outrigger aluminum splint, sandwiched between layers of a short-arm fiberglass splint, kept the tendon immobile until a wound check five days later. All was well, and the splinting was continued for three more weeks. The patient made a full and uneventful recovery without reopening the laceration or suturing the tendon. The partial laceration could have been converted into a full rupture if not recognized and had proper inspection and precautions not been taken. It pays to be paranoid; you just cannot go wrong by overdiagnosing such injuries.

A puncture wound to the palm is the EP's most challenging case. It's unlikely that this injury would not wreak havoc with at least some of the finely tuned biomechanical interplay of pulley systems, synovial sheaths, and intrinsic musculotendinous structures deep inside the hand. A puncture wound cannot be readily cleaned, but do not put an irrigation catheter into the wound to pressure-irrigate. Carefully extending the puncture with a scalpel is one option for better cleansing. Pain and weakness in the palm when the fingers are flexed against resistance may signal a partial tendon injury, but a final diagnosis is likely not possible in the ED. Treat, consult, and splint for the worst, and be thankful you are not providing definitive care.

A puncture wound to the palm is the EP's most challenging case. It's unlikely that this injury would not wreak havoc with at least some of the finely tuned biomechanical interplay of pulley systems, synovial sheaths, and intrinsic musculotendinous structures deep inside the hand. A puncture wound cannot be readily cleaned, but do not put an irrigation catheter into the wound to pressure-irrigate. Carefully extending the puncture with a scalpel is one option for better cleansing. Pain and weakness in the palm when the fingers are flexed against resistance may signal a partial tendon injury, but a final diagnosis is likely not possible in the ED. Treat, consult, and splint for the worst, and be thankful you are not providing definitive care.

Most people who can negotiate an office visit with a hard-to-access hand surgeon can at least cooperate with the examination and voice subjective complaints. Not so in the ED at 3 a.m. Every article on the treatment of hand injuries states that the patient must be cooperative, alert, and otherwise intelligent enough to participate in his care, obviously a naïve assumption by someone who has never worked an ED shift (aka a hand surgeon). Intelligence and cooperation are not prerequisites for any ED visit, and the EP is often faced with a situation that makes proper evaluation simply impossible. Occasionally a few hours of sobering up, a shot of morphine or a lidocaine injection, or the help of a caretaker or family member can facilitate an examination, but it's unrealistic to believe that you will always glean all the information you are requesting on the first visit. Fortunately, there are few times when you have to commit totally to a specific diagnosis, so share the liability with a colleague, and have the patient assume some personal responsibility.

It's best to consider the worst-case scenario. Subjective numbness, less than perfect motor function, varying light touch sensation, and only three of five two-point discrimination tests positive may be due to malingering, anxiety, alcohol, or local inflammation or swelling. The crafty clinician, however, assumes that inconsistent or ambiguous findings suggest a possible problem, perhaps a partial tendon or nerve injury, but certainly a problem that needs another evaluation in a few days after the rage, alcohol, and pain have dissipated.

Actually, the uncooperative patient who has an equivocal examination is a very straightforward case. One simply assumes that there is a tendon or nerve injury, and proceeds along the standard guidelines for treatment and referral for such pathology. If you are wrong, nobody cares, and you look like a concerned pro. I again caution the clinician to believe a patient when he says he can't feel normally or won't move a finger, even if the laceration looks benign and the exam is anatomically screwy. Complete absence of flexion or persistent numbness is rarely conversion, malingering, or noncompliance.

Even a tendon that is 80 to 90 percent lacerated can flex the finger, but if left alone, it will surely rupture later. This should not be a surprise finding 10 days later when the sutures are removed. When some function is preserved, subtle clues to the presence of a partial tendon laceration are weakness of flexion against resistance and pain in the laceration with passive and active flexion.

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Definitive Therapy

Partial flexor tendon injuries, even significant ones, are commonly handled without surgical repair. But even in this day, there is controversy about the best course of action for known partial tendon lacerations. (J Hand SurgAm 2001;26[5]:821; Plast Reconstr Surg 1977;59[2]:231; J Biomech Eng 2000;122[6]:604; J Bone Joint Surg Am 2002:84-A[6]:1006.) All sorts of trimming procedures, splinting, and physical therapy protocols have been advocated. eMedicine details about 20 different suture configurations. Once healed, sutured tendons are not as strong as those allowed to heal without surgery, so allowing natural healing is acceptable as long as the tendon is protected. Fortunately, EPs don't have to know the specifics.

As a general rule, most surgeons will not suture a tendon that is cut 50 percent or less. Others allow even greater partial lacerations to go unsutured. Some evidence suggests that suturing a partial tendon laceration provides a worse outcome than splinting and physical therapy. Of course, one has to make the diagnosis of a partial tendon laceration in the first place, before the course of therapy is set. Some surgeons will explore a laceration with the thought of obtaining definitive information on the extent of injury, and then make a decision.

Most hand surgeons prefer to make a definitive evaluation or repair complete flexor tendon lacerations a number of days post-injury. This fits nicely with a two- to three-day first office visit or clinic follow-up after the ED visit. This often, however, requires the EP to stress the importance of follow-up to the patient, and occasionally help with the appointment. Unless the EP becomes personally involved, no patient in my ED has easy access to a Philadelphia hand surgeon in two to three days, even with insurance, persistence with an office appointment desk, and a good command of English.

Occasionally a primary repair will occur on the same day as the ED visit if the wound is clean and the surgeon available. I rarely encounter this scenario. A general standard mandates that any primary repair of tendons, nerves, or arteries be done when the wound is clean, and there are no associated injuries, bleeding has been controlled, edema has subsided, and the wound is infection-free. Many surgeons prefer to operate two to three days after the ED visit, but that means they believe your exam in the first place. Practice varies, so get it in writing on the chart.

A delayed primary repair can be performed up to 10 days after injury with reasonable results. A secondary repair of a flexor tendon can be performed within two to four weeks post-injury. Generally, the results are equal with immediate, delayed, and early secondary repair. Repair of flexor tendons after three to four weeks is often fraught with poor results, however.

A missed flexor tendon injury that progresses from partial to complete rupture by suture removal is generally amenable to a final result similar to that expected if the diagnosis had been made in the ED. But this is an inopportune time to make the diagnosis. Because flexor tendons often have some morbidity under the best of circumstances, making the diagnosis as soon as possible is preferable. After three to four weeks, a two-stage procedure, tendon transfers, or tendon grafting are often required, usually with stiffness and lack of full range of motion being the final result.

Patients who are noncompliant, have financial problems, or lack transportation or the requisite social support are a nightmare for all physicians. Everything can be done correctly, and all follow-up carefully spelled out, yet the patient and the hand surgeon never meet within the appropriate timeframe or consistently enough to get the best possible result. Unfortunately, the EP is often blamed for the poor outcome, regardless of gargantuan (but often undocumented) time and efforts during the initial visit. The most common response to a bad outcome are allegations that the EP missed an injury, failed to seek proper consultation in the ED, or never informed the patient of the important issues or possible consequences. This is where proper and detailed charting saves the day. I have seen many charts that state only: “N/V/T intact.” While this seems standard, and is OK if nothing is actually askew, get into the habit of performing your best hand exam on all cases, even those with minimal findings, just to keep in practice.

When in doubt or to finalize the otherwise ideal ED encounter, short-term splinting of all injuries, even remotely potential problems, can never be faulted. Consider a routine repeat examination within a few days of most injuries to ferret out unexpected complications. Expectant treatment and even a documented incorrect overdiagnosis that erred on the side of caution should be the clinician's mantra.

Next month: Extensor tendon-injuries.

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Dr. Roberts

Dr. Roberts

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Reader Feedback:

Readers are invited to ask specific questions and offer personal experiences, comments, or observations on InFocus topics. Literature references are appreciated. Pertinent responses will be published in a future issue. Please send comments to emn@lww.com. Dr. Roberts requests feedback on this month's column, especially personal experiences with successes, failures, and technique.

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