Introduction
The ideal treatment of flexor tendon injuries under almost every circumstance is primary repair as it is easier to rehabilitate a digit over the several months after injury with the digit flexing actively rather than being flexed passively. However, primary surgery is not always possible, and a percentage of primary repairs may become adherent to their surrounds, gap, or rupture. Secondary flexor tendon surgery includes (1) tenolysis, (2) tendon grafting, and (3) pulley reconstruction and skin replacement over the tendons.
In many parts of the world, it is now uncommon for a patient with divided flexor tendons not to undergo primary repair. Consequently, secondary surgery is largely that of the complications of primary repair, namely ruptured and adherent repairs, with each of these complications occurring with an incidence of around 5%. Given that the reports come from units with a particular interest in this subject, this is probably an underestimate of the general incidence of these problems after primary repair in the digital tendon sheaths. The introduction of 4 and 6-strand core suturing has reduced but not eliminated repair rupture. Where the primary referral service is poor, the surgeon faces different problems. The situation may be simply an extended finger with no active flexion. However, it may be much more complex.
Consideration of both the primary injury and the patient is important. In earlier days, many hands with severe injuries would never have been considered for secondary flexor surgery and had finger amputation. For various reasons, this group of patients will include cases likely to do badly whatever one does and who may do no better after secondary surgery than they did the first time, if they have already undergone primary surgery. Among them will be a few uncooperative patients.
Timing, requirements, and contraindications
Although we can achieve flexor function by secondary techniques, the reported results of primary treatment are better than those of secondary surgery, and, wherever possible, we try to avoid secondary procedures.
Avoiding secondary surgery
Techniques evolved over the last 40 years, such as strengthening sutures, correct pulley management, good rehabilitation, and appropriate patient management, and have tilted the balance to primary repair worldwide. Use of various technical “tricks” may also allow us to avoid secondary surgery. (1) The advantage of repairing only the flexor digitorum profundus (FDP) tendon under the A2 pulley or completely venting the A2 pulley, which have been discussed in a previous chapter. (2) Intramuscular lengthening of the proximal tendon may avoid grafting after delayed presentation of a divided flexor pollicis longus (FPL) ( Fig. 16.1 ) or, occasionally, a finger flexor and can allow repair of any digital flexor distally when a small segment of the tendon is missing ( Fig. 16.2 ). Where distal tenolysis does not achieve full digital extension because of proximal muscle shortening, this technique can also be usefully employed. A single tendon cut within the muscle gives about half a centimeter in extra tendon length distally. Repeated about 1 to 2 cm from the first cut, but still within the muscle, will give another quarter centimeter of lengthening. Although the tendon is cut, continuity is maintained by the muscle, allowing immediate mobilization. (3) Secondary surgery can be avoided after FDP pull-off presenting late by halving the distal part of the swollen tendon and passing one-half of the tendon through the A4 pulley to reattach it ( Fig. 16.3 ). (4) McFarlane and colleagues, in a study of 100 patients presenting late with complete flexor tendon division(s), identified the fact that delayed primary repair was possible in 36 fingers, with 14 being repaired after a delay of 1 year or more. Therefore late presentations should not automatically be scheduled for grafting but explored immediately. Now, with knowledge of Le Viet’s technique of intramuscular lengthening of the proximal tendon, primary repair may be possible in more than 36 of 100 fingers. (5) Re-repairing ruptures, when possible, reduces the number of secondary procedures needed: of 40 re-repairs in zones 1 and 2 done in the lead author’s unit, about 50% eventually had good or excellent results, with the results being considerably better in the three radial fingers.
The option of doing nothing is used occasionally as a long-term solution, usually in the elderly. Occasional other patients may not want, or be unable to spare further time for, delayed re-repair or grafting surgery. This is not uncommon with FPL divisions not repaired primarily, particularly in the nondominant thumb ( Fig. 16.4 ). A decision to do nothing can be reversed after any length of delay until old age intervenes. When this long-term course is chosen, the patient buddy-straps the flail finger to the adjacent finger to stop it catching during activity, or, in the case of a thumb with no flexor function of the interphalangeal (IP) joint, flexes the thumb at the basal and/or metacarpophalangeal (MCP) joints only.
Where only the FDP has been divided, the flexor digitorum superficialis (FDS) may provide adequate finger flexion for some, but not for others. The decision to tendon graft in cases with an intact and functioning FDS and divided FDP tendon has been greatly debated, and many surgeons will not contemplate it for fear of compromising FDS function. Sacrificing distal interphalangeal (DIP) joint flexion is a simple alternative to tendon grafting.
Timing and requirements of secondary surgery
Secondary surgery is undertaken at least 3 months after trauma or when primary repair is impossible or fails. A requirement is acceptable passive motion of the digits and good soft-tissue cover ( Box 16.1 ). Otherwise, the secondary surgery will have little chance of success. If the soft-tissue cover is not good or passive digital motion is not ideal, more time should be given to improving the soft-tissue conditions or for the therapists to improve the passive digital motion. Specific indications for tenolysis, pulley reconstructions and tendon grafting are discussed later, including appropriate surgical procedures.
- 1.
Timing: All secondary surgeries should be at least 3 months after primary injury or failed primary repair. Requirements: range of passive motion of the joints is normal or reasonably good. In addition, skin and soft tissue should be supple.
- 2.
Tenolysis is indicated in patients fulfilling two criteria:
(1) a lack of improvement in active range of motion after therapy for several weeks; and (2) when the patient has already been 3 to 6 months after tendon repair.
- 3.
One-stage tendon grafting is indicated in the patient with (1) loss of tendon substances, or (2) failed primary repairs, but there is no destruction of pulleys or only destruction of one or two pulleys, so pulley reconstruction is not necessary and there is no need for surgery to regain good skin cover.
- 4.
When there are dense adhesions, or loss of tendon substance, with lengthy destruction of pulleys, two-stage tendon reconstruction is indicated. The first-stage surgery is the insertion of a silicone rod and reconstruction of pulleys over the rod. The second-stage surgery (performed at least 3 months after the first-stage involves removal of the silicone rod out and insertion of a tendon graft.
- 5.
In the patient with extensive destruction of the pulleys, bowstringing will occur and pulley reconstruction becomes necessary, using an flexor digitorum superficialis or a palmaris longus graft. In these patients, the scarring is usually extensive, so two-stage reconstruction is usually indicated, with new pulleys being reconstructed over a silicone rod at the first-stage surgery.
Contraindications
Patients may present with specific problems recognized to be unsuitable for secondary flexor surgery. Perhaps the patient requesting flexor reconstruction of a longstanding injury to the adult index finger is the most well-known example: pinch to the middle finger has already been established at a cerebral level and cannot be reversed in an adult. More controversial is the contraindication to FDP reconstruction through an intact FDS flexor in a finger with full FDS flexion of the PIP joint.
Some patients will be unsuitable for secondary surgery. Many will have failed primary surgery. Some will have presented late because of other priorities that may still pertain. Dissuading a patient from secondary surgery under these circumstances may be more difficult than agreeing to his, or her, request. Uncooperative patients may be considered unsuitable for staged tendon graft reconstruction, which requires lengthy treatment and therapy.
Indications and methods of each procedure
Tenolysis
Indications.
Tenolysis is indicated when (1) there is a lack of improvement in active range of motion after active rehabilitation for several weeks, (2) it is already 3 to 6 months after tendon repair and the passive range of the motion is normal or close to normal, and soft tissue in the area of surgery is supple ( Box 16.1 ). Waiting at least 3 months is to prevent weakening of the tendon repair site and to allow time to let the adhesions mature and avoid compounding the adhesions by the further surgery. The patient’s compliance is a further factor to consider, because this procedure requires the patient’s willingness to, once again, undergo a therapy program.
Methods.
Tendon adhesions most commonly occur at the surgical site but may occur along more of the tendon length. The surgical approach may use the same incision as any previous primary surgery or, in the digits, use a mid-lateral incision (see later). Adhesions are often encountered between the FDP and FDS tendons, and these need to be separated carefully. Sacrificing the FDS tendon may be necessary for FDP gliding and FDS excision has not been shown to impact total active motion. Adhesions may also form between the tendons and the pulleys/sheath and these are teased apart carefully.
Excision of some pulleys is often necessary as they are embedded in adhesions or already fibrotic. However, lengthy excision of pulleys, such as removal of both A1 and A2, or from A2 to A4, should be avoided. As much as possible of the important pulleys, viz. A2 and A4, should be retained ( Box 16.2 ). However, part of the long A2 pulley can be excised if it is embedded in dense adhesions and A4 can be completely excised provided the sheath proximal to A4 is largely intact. Tendon bowstringing is checked after tenolysis either by active digital flexion or by pulling on the tendons proximally, depending on the method of anesthesia used ( Fig. 16.5 ). Tendons can tolerate some degrees of bowstringing, but visible bowstringing after lengthy pulley loss may need reconstruction of one or two pulleys in the area of pulley loss.
- 1.
In tenolysis, the important pulleys should be preserved if possible.
- 2.
A judgment is made at surgery as to whether the tendon is strong enough or frayed. If the tendon is badly frayed, the procedure is changed to two-stage tendon reconstruction.
- 3.
Tenolysis is either done under local anesthetic without tourniquet, so the patient can move actively, to ensure tenolysis is complete or, when more proximal anesthesia is used, tenolysis is checked by pulling on the tendons proximally.
- 4.
A full range of active motion is ideal after this surgery.
- 5.
Palmaris longus tendon is the most often used donor for tendon grafting. Plantaris and extensor indicis (EI) are used where PL is absent.
- 6.
As many pulleys should be preserved as possible. A minimum of an A2 and an A4 pulley should be preserved or reconstructed. At tenolysis, preserving an A3 pulley also is advised in case the A4 pulley is deficient or is damaged later in the tenolysis.
- 7.
Grafted tendons can be tensioned at the proximal junction or distally with the finger cascade being used to determine the appropriate tension.
- 8.
After one or two-stage tendon grafting, early active motion, using motion protocols similar to those used after primary repair, can be used.
Passive motion of the individual joints and the effect of this on the flexor tendon is helpful in determining whether or not there are remaining adhesions. Tenolysis is now commonly carried out under wide-awake local anesthesia with no tourniquet, because the surgeon can ask the patient to move their digit actively intraoperatively ( Box 16.2 ). This should identify remaining adhesions blocking a full range of motion. Active flexion of the digit also helps break down any remaining adhesions and also ensures the tendon is strong enough for active gliding. It can also demonstrate the motion arc to the patient, thereby motivating the patient to maintain this degree of motion during therapy after surgery. The more traditional technique of passively pulling on the freed tendons proximally after more extensive proximal anesthesia is still widely used and is an acceptable alternative.
Postoperative care.
All cases undergoing tenolysis are treated with antibiotics postoperatively to prevent infection. There is no repair to protect, so much more aggressive active and passive rehabilitation can be started soon after surgery. Starting exercises 3 to 4 days after surgery avoids risk of bleeding and the pain normal to the first few days after surgery. The patient should aim to maintain the range of motion they have achieved during surgery ( Box 16.2 ). The frequency of motion and exercise regime can vary, but in general more sessions and frequent active motion exercises are encouraged. The therapy should last for at least 6 to 8 weeks, as adhesions may form again in this time period. After 8 to 10 weeks, tissue healing matures and gliding beds for the tendons have formed, so the chance of further adhesion diminishes.
In the first few days after surgery, the active motion can be under a continuous local anesthetic infusion through a percutaneous cannula proximal to the site of surgery onto the median or ulnar nerves, or their branches in the palm, to achieve as much motion as possible as early as possible. The introduction of “Pain Buster” balloons, slowly infusing local anesthetic onto the operation site, or the nerves proximal to the site, have facilitated outpatient use of this technique.
A more gentle “frayed tendon program” of rehabilitation was advocated by Strickland in cases with frayed, or thin, tendons and/or poor soft-tissue cover of the palmar aspect of the digit. Although, theoretically, this may be safer in such cases, it places an onus on the therapists to carry out a regimen of treatment that is not their norm without rupturing poor tendons. We prefer to replace such tendons with silicone rods and carry out secondary grafting followed by routine therapy management, thus placing judgment concerning tendon survival back in the operating theater.
Intraoperative decision for a tendon graft.
Sometimes severely scarred or badly frayed tendons cannot be freed without irrevocable damage to the tendons or the vital pulleys ( Fig. 16.6 ). In these cases, tendon grafting and/or pulley reconstructions will be necessary after freeing the palmar side of the finger from the scarring in the other tissues and excising the tendons ( Box 16.2 ). Necessity, or preference, may determine that this be done at the same operation, but such cases lend themselves to two-stage tendon reconstruction, first because the degree of scarring is severe and also because pulley reconstruction over a rod, which does not have to cope with the forces of immediate tendon activity, is much simpler to manage ( Fig. 16.7 ).
Clinical testing of cases with incomplete ranges of movement, whether prior or subsequent to grafting or tenolysis, very frequently identifies a passive loss of flexion of the involved digit, indicating extensor tendon tethering to their surrounds and joint dorsal and lateral ligament tightening by fibrin and, later, scar. This is a more common reason for loss of flexion than flexor tendon adherence, although both may occur concurrently. The result of any flexor tendon release or reconstruction can only be as good as the maximum passive flexion of the joints. Where identified preoperatively, this problem should be addressed by therapy, occasionally by surgery, before the flexor surgery is undertaken.
Tendon grafting: One-stage
Indications.
One-stage tendon grafting is used routinely by one coauthor (SGX) and his colleagues, and is used by many other surgeons where there has been no destruction of pulleys or only destruction of one or two pulleys in a narrow area and pulley reconstruction is not necessary.
Methods.
The palmaris longus (PL) tendon is the common donor of the graft. The extensor indicis proprius is another useful donor. Both donors are in the same surgical field and easy to harvest. The PL tendon is absent in about 15% of the forearm. Therefore preoperative assessment is needed to ascertain its presence. The PL tendon from the contralateral forearm and tendons from the leg or foot can be used but require further anesthesia. In harvesting the PL tendon, a tendon grasper or vein stripper can be used through a single incision in the distal forearm or the tendon can be removed through a distal incision and a second small incision in the midforearm overlying the musculo-tendinous junction.
When carried out as a single procedure, the tendons are removed from the digit through incisions in the tendon sheath intended to preserve as much of the sheath as possible and, at the very least, preserve the A2 and A4 pulleys. The FDS tendon is only removed if not intact or grossly swollen. If the PIP joint can hyperextend at the time of surgery, the distal part of the FDS tendon must be retained, or replaced, to prevent swan-necking of the joint.
The distal attachment of the tendon graft traditionally uses a pull-out suture tied over a button lying on the nail plate, but the authors have found this to be unnecessary. The lead author uses reattachment of the detached FDP and tendon grafts to the end tuft of the distal phalanx without a button. One coauthor (SGX) uses direct suture of the grafted tendon to the FDP stump near its insertion, or sutures the graft to the FDP tendon after making a fish-mouth incision in the FDP tendon ( Fig. 16.8 ). We believe pull-out sutures should not be used because they may damage the nail and, occasionally, the button catches and pulls off, snapping the suture. These alternative methods are equally strong and reliable.
The proximal part of the graft is sutured to either the retracted FDP or the FDS tendon in the palm or at the wrist with a Purvertaft weave with the finger in a moderately flexed position ( Box 16.2 ). The finger cascade is used in deciding the appropriate tension to set the proximal suture ( Fig. 16.9 ). Some surgeons prefer to tension the tendon by performing the proximal weave first and tension the tendon distally, using one of the modifications of the distal attachment technique to the nail originally described by Pulvertaft. ,
Postoperative care.
After surgery, the finger can undergo early active flexion exercise as used after primary repair. Splint protection is necessary for the first 5 to 6 weeks. The wrist and finger are splinted in a slightly flexed position with the splint beyond the fingertips. Some surgeons and therapists allow active motion exercises out-of-splint. If the tension of the grafted tendon becomes loose over time, a small incision can be made in the palm to fold and suture the folded part of the grafted tendon to tighten it One coauthor (SGX) infrequently needs tenolysis, and one-stage grafting has been routine for decades when pulleys do not need reconstruction with most sheath intact.
Staged reconstruction
Indications.
Staged reconstruction consists of two procedures: (1) placement of a silicone rod, often with pulley reconstruction and/or skin replacement and, three months later, (2) a tendon graft replacement the silicone rod. Staged reconstruction is indicated by some surgeons for all grafting procedures and by some only in patients with (1) lengthy pulley destruction and/or (2) extensive scarring of the tendon gliding bed ( Box 16.1 ).
Two-stage grafting was introduced to improve the bed into which the tendon graft is placed by creation of a pseudosheath, by inserting a flexible silicone rod into the hand at a first operation and delaying the grafting procedure for several months, because of dissatisfaction with the results of the one-stage procedure. , The perceived advantages of two-stage grafting is that mobilization is started (1) with the graft moving in a smooth-walled pseudo-sheath and (2) in a less painful and more supple, rested hand.
Although single-stage tendon grafting has an apparent advantage in terms of a single period off work, it carries a risk of graft adherence, requiring further surgery, as the grafted tendon is being placed in a bed from which the old tendons have just been excised. Should tenolysis then be necessary, the grafted tendon is lying in a scarred bed from the tenolysis. The results of any secondary flexor surgery are very much dependent on the degree of scarring in the finger and hand. Although two-stage grafting may seem to be overkill when the sheath is not badly scarred at surgery, those who favor this technique would argue that (1) it is impossible to tell how much scarring there will be after grafting in any individual patient or (2) what effect even very small degrees of scarring will have on the ability of any particular patient to maintain movement after surgery. A further considerations in favor of the two-stage approach is the unknown of the patient’s psychological make-up and ability to cooperate with the surgeons and therapists postoperatively. This is more likely to be known, possibly compensated for, by the second of two operations.
First-stage procedure.
When two-stage grafting is used, the original FDP and FDS tendons are removed at the first operation, leaving only an adequate length of the distal FDP to which the graft can be sutured at the second stage. Others who used alternative means of distal attachment leave only 0.5 cm of the FDP tendon attached to the distal phalanx, with a tunnel prepared behind this tendon remnant into which the distal end of the tendon graft will be “snugged” later. Some surgeons leave, or replace, the distal part of the FDS tendon to prevent swan-necking of this joint: this is only necessary if the particular PIP joint can extend beyond the straight position. Proximally, the tendon of the intended motor unit is held to physiological length by suturing it, with one or two nonabsorbable 2/0 or 3/0 sutures, to the deep transverse ligament in the palm or the ligaments at the flexor aspect of the wrist, depending on the site to be used later for proximal attachment of the graft.
In the digit, as many as possible of the original pulleys are preserved. A silicone rod of appropriate diameter to the tendon sheath is then passed through the preserved sheath from the distal end of the proximal motor tendon to the distal phalanx. If a variable diameter tendon rod is used, it is passed through the sheath until the part of appropriate diameter fits comfortably, then the two ends are cut off. The distal end of the rod is cut obliquely and passed behind, and then sutured to, the distal FDP stump. The free proximal end of the rod is not sutured and should reach slightly proximal to the sutured motor tendon at the mid-palm or wrist. If there is lengthy segmental loss of two or more pulleys, especially both A2 and A4 pulleys, pulleys are reconstructed over the rod ( Fig. 16.10 ). The methods of reconstructing the pulleys are given later in the text about tendon bowstringing.
