Chapter 19 Treatment of Rupture of Primary Flexor Tendon Repairs

Outline

Clinical series of primary flexor tendon repairs worldwide, using a variety of suture materials and suture configurations, all include a small, but ever present, rupture rate. That the assumption that stronger sutures will “cure” the problem may be false is discussed and the role of the sheath and of the patient considered. Immediate re-repair of ruptures has been carried out for many years without analysis of the success of this procedure. This chapter discusses a study of the effectiveness of immediate re-repair of ruptures of the primary repair. It identifies that this works adequately for all digits but the little finger. Possible modifications of the method of re-repair used in this study which might improve the results are discussed and an alternative management plan for the little finger is considered.

Rupture of the tendon repair, or detachment of the reinserted tendon, if recognised immediately, should be treated with prompt re-exploration and repair.

Leddy, 1982¹

With a few exceptions, most studies published during the past 25 years discussing acute flexor tendon repair and early mobilization report a rupture rate of between 3% and 9%. In studies of less than 100 patients, which are the norm for this field, these figures indicate negligible differences in the number of patients with ruptured tendon repairs in different units using a multitude of core and circumferential suture techniques and many variations of the three basic regimes of early postoperative mobilization.

The Suture

Survey of the many new suture techniques used throughout the past 20 years confirms that the Savage six-strand suture ^2,³ is still the strongest suture, although it is difficult to use. One could argue that 20 years have been spent trying to achieve a simpler suture with equal strength. Two curious facts should make us wary of this search for the perfect suture configuration. Savage reported one rupture in 20 fingers and 3 thumbs with zone 2 complete flexor divisions repaired with a six-strand suture, a rupture rate in the fingers of 5% or a rupture rate of 3% overall.² Harris et al,⁴ reporting results from my own unit from June 1989 to December 1996, recorded 17 ruptures in a series of 397 fingers (4%) with zone 2 complete flexor divisions using a two strand modified Kessler core suture. So simply putting in more complex sutures is possibly not the answer, or not the only answer.

A very interesting laboratory study from Professor McGrouther’s laboratory in Manchester ⁵ showed that even a single suture passed through a tendon significantly affects the cell population of the tendon around it: the suture foreign body causes the tenocytes to move away. So, perhaps, we are, unwittingly, making tendon repair breakdown more likely as we put more foreign suture material into the tendon.

The Patient

This may be the reason why we cannot get past an inevitable rupture rate, although it is probably more likely that it is simply human nature that is defeating us. In 1999, we highlighted the role of patient irresponsibility in the etiology of rupture of primary flexor tendon repairs.⁴ This study included 526 fingers in 440 patients with primary flexor tendon repairs in zones 1 and 2 who underwent surgery and postoperative mobilization in a controlled or early active motion. Twenty-three patients ruptured 28 tendon repair(s) in 23 fingers, an overall rupture rate of 4%. Eleven of these, just less than half, occurred as a result of patients using the hand, in or out of their splint, against therapy advice. It is likely than this figure is an underestimate of this problem of patient noncompliance in this population worldwide.

The Sheath

In a laboratory study, Tang et al ⁶ identified a further possible factor in the etiology of these ruptures. These authors suggested that repair rupture is most likely to occur at sites where tendons glide over a rim of a major pulley or over gliding curves of a small diameter, characteristics found typically in zone 2B repairs and repairs of tendons in little fingers. In our study, described later, 32 of a total of 42 fingers (77%) requiring re-repair of the flexor tendons occurred in zone 2B and/or in little fingers.⁷

Timing of Occurence of the Rupture

The times after primary repair at which the ruptures occurred are shown in Table 19-1, which contains information from our unit in 62 fingers in 61 patients who ruptured primary zone 1 and 2 finger flexor tendon repairs. The average time to rupture of the primary repairs was 18 days (range, 3 to 61 days). The highest incidence of rupture of primary finger flexor tendon repairs was seen in the second week after surgery. The incidence of rupture was higher in the first 5 weeks after surgery than in the later 4 weeks (weeks 6 to 9).

Table 19-1 Timing of Ruptures of Primary Finger Flexor Tendon Repair in a Total of 62 Fingers