Chronic flexor tendon lesions: reconstruction in two stages

Abstracts

Os autores apresentam resultados de tratamento de lesões crônicas dos tendões flexores na mão, usando técnica em dois estágios. O primeiro pelo implante de prótese de silicone e o segundo com enxerto de tendão. Dão detalhes de técnica, e analisam seus resultados comparando-os com os da literatura. Chegam a conclusão que a técnica dá resultados satisfatórios na maioria dos casos.

Tendões flexores; lesões crônicas; enxertos de tendão

ARTIGO ORIGINAL

Chronic flexor tendon lesions — Reconstruction in two stages

Samuel Ribak^I; Marcelo Rosa de Resende^II; Robinson Dalapria^III; Edison Hirata^III; Márcia Muquy^IV; Renato Pinheiro Cordeiro^IV; Dirceu de Andrade^V; Celso Silva Toledo^V

^IPreceptor. Master Degreein Orthopedics, FMUSP

^IIIOT Assistant Doctor — "Hospital das Clínicas", FMUSP

^IIIOrthopedic Surgeon

^IVResidents of the Hospital Nossa Senhora do Pari

^VDirectors of Hospital Nossa Senhora do Pari

^{Correspondence}

SUMMARY

The authors present the results of a two-stage treatment of chronic flexor tendon injuries of the hand. In the first stage a silicone prosthesis is implanted and in the second stage a tendon graft. Details of the technique and results of the analysis are presented and compared with the scientific literature. The authors concluded that satisfactory results were achieved in most of the cases.

Key Words: Flexor tendon, chronic injuries, tendinous grafting.

INTRODUCTION

The treatment of chronic lesions in the hand flexor tendons is challenging due to the high frequency of adherence of the tendon used as graft.

The current concept of treatment for that kind of lesion is reconstruction in two stages. In the first, a synthetic material is placed in the trajectory of the tendon to form a tunnel which can receive the biological graft to be used in the second stage of reconstruction.

The utilization of implants was introduced⁽¹³⁾ in 1936, in a classic experience with celluloid tubes, where a pseudoshaft was formed, composed by cells adapted to accept a sliding structure, in that case the tendon structure. That technique failed since the material was too rigid and prevented the passive mobilization of the articulations resulting in rigidity of the finger. Only in 1963⁽²⁾ the utilization of rods made of a more flexible silicone type material was instituted.

Other proposals of two-stage treatment⁽¹⁴⁾ study (1969), mentioned the utilization of tendon grafts, as the vascularized superficial flexor of the same finger that, in spite of being very interesting, did not consider the utilization of the implant in a first moment. In 1971 refined and detailed the technique of tendon reconstruction in two stages as it is presently known, with clinical reports and good results⁽¹⁰⁾.

The quotation⁽¹⁾ reflects the importance of this theme: "The flexor tendons are part of a very important anatomical-physiological aspect of the hand. They are the main elements which act in prehension movements: strong and vigorous prehension of the worker that holds a hammer, delicate and subtle prehension of the designer who traces the lines of a face, or of a surgeon who uses the scalpel in rapid and accurate movements. If for the worker disability of the hands means loss of capacity to work, for others it represents a spectrum of difficulties starting with the daily life relationships."

Although there is a consensus as concerns reconstruction of the flexor tendons chronic lesions, we observe great disparity as concerns the results, often not very encouraging and this led us to report our experiences in this study. Considering our results we propose a discussion about the factors which can contribute to promote more satisfactory results.

CASUISTIC

Thirty-six fingers of 24 patients (20 males and 4 females) operated on from 1994 to 1997. The ages ranged from 6 to 47 years, mean 20 years. The most compromised finger was the 2^nd chirodactylo (44%) and the most lesioned zone was type II according to the Verdan classification⁽¹⁹⁾ in 22 cases (88%).

The time span between the injury and the 1^st surgical stage ranged from 1.5 months to 20 months, mean 3 months.

A general summary of the casuistic is presented (Table 1): number of order, initials of patients, age, sex, type of the lesion, localization of the lesions with their respective zones and time span between the injury and the 1^st surgical stage.

All the patients were pre-operatively assessed and classified⁽⁶⁾ considering extension of the lesion and establishing prognosis. (Table 2).

METHODS

Surgical technique

First stage

The 1^st stage con-sists of a technique to implant a silicone rod all through the flexor tendon until the distal phalanx of the fingers. Some surgical complementary and necessary procedures as capsulotomy or reparation of associated lesions as the digital nerve are also carried out in this stage. We approach the lesion through the Bruner⁽⁸⁾ Zig-Zag volar incision (Fig. 1).

The positioning of the silicone rod in the injured finger starts with the insertion of the deep flexor in the distal phalanx until the distal third of the forearm (Fig. 2).

Distally, we always suture the rod to the stump of the remanescent flexor tendon in the distal phalanx, however proximally we let it free. The rod is always passed through the remanescent pulleys (Fig. 3,4).

In this 1^st stage, when necessary, we reconstruct pulleys A2 and A4 to avoid the "arch" effect. We use two kinds of tissue, or a portion of the injured finger superficial flexor tendon, or a strip of the extensor retinaculus approximately 0.5 cm wide at the wrist level. Concerning reconstruction, we use two techniques: type I⁽¹¹⁾, used in 7 cases in which we suture the strip to the fibrous borders of the former shaft; type II ^(2,12), in 11 cases, in which we embrace and surround all bone phalanges under the extensors in the proximal phalanx and over in the middle phalanx (Figs. 5 and 6).

Three days after surgery, we institute passive mobilization of the metacarpus and interphalangeal articulations.

SECOND STAGE

After a minimum period of 04 (four) months when a pellicle forms around the silicone creating a new tunnel, we carry out the second phase of the tendoplasty. In this intervention we approach with diminute incisions the sites of the proximal and distal extremities of the already installed silicone rod and substitute this rod by the tendon graft (Figs. 7,8).

The grafts came from: ipsilateral long palmar, contralateral long palmar, thin plantar and short extensor of the toes (Figs. 9,10).

The graft trajectory was always from distal to proximal, inside the new tunnel (Fig. 11)

Distally, we suture the graft to the stump of the remanescent deep flexor tendon inserted in the distal phalanx. To reinforce this suture, we carry out the "Pull Out" technique⁽¹⁴⁾. The suture proximal to the graft was carried out in the deep flexor tendon, superficially to the injured finger. In some lesions, we use as motor force the superficial tendon of the adjacent finger, generally the 4^th finger. All the sutures are carried out using the Pulvertaft⁽¹⁵⁾ technique. Tension of this suture maintains the finger in a flexion grade higher than the other fingers in the rest position, where the suture was made in the lesioned tendon itself. (Fig. 12).

During the post-surgical period the wrist is maintained in neutral extension, the metacarpophalangeal articulations in 80º and the interphalangeal in 0º. Passive mobility started in the fifth day after surgery and active mobility without resistance in the 18º day. The patients used orthesis during six weeks.

A general summary of the method is (Table 3), with number of order, initials of the patients, type of the reconstructed pulley, type of reconstruction of the pulley, origin of the grafts, and type of tendon used as motor in the graft proximal suture.

RESULTS

In the post-surgical evaluation WHITE's⁽²¹⁾ method was used, based in the following parameters: loss of extension, total sum of flexion of the interphalangeal and metacarpophalangeal articulations and of the Pulp-Palm distance, as (Table 4 and figures 13,14 and 15).

The results are presented (Table 5), according to the evaluation criteria proposed by WHITE.

Analyzing the results 5.5% were considered excellent (2 fingers), 61.1% good (22 fingers), 16.6% regular (6 fingers), and 16.7% bad (6 fingers).

COMPLICATIONS

Ten patients had the following complications in 17 fingers:

Adherence at the proximal suture in 3 fingers (8.3%). Patients numbers: 01 — 2^nd QDE — 03 - 4^th QDE, 06 — 5^th QDE and distal in 6 fingers (16.6%) 6 — 4^th QDE, 7 — 2^nd QDD, 10 — 4^th QDD, 15 — 3^rd QDD, 13 — 2^nd QDE, 21 — 2^nd QDD.

Infection in 2 fingers (5.5%). Patients numbers: 21 — 2^nd QDD, 1 — 4^th QDE, migration of the silicone rod in 1 finger (2.7%). Patient number 17 — 4^th QDD.

Tendon loosening in 4 fingers (11.1%). Patients numbers 10 — 3^rd QDD, 18 — 3^rd QDD, 2 — 3^rd QDE, 2 — 4^th QDE and "arch" in 1 finger (2.7%), patient number 19 — 4^th QDD. No cases of tendon graft rupture or sinovitis were observed.

In the cases of adherence, tendolysis was carried out in a second occasion in all the patients. The cases of infection were treated with antibiotics and re-operated on in a second occasion. In the patients with rod migration, repositioning was carried out; afterwards, the normal surgical technique was used in the cases with visible tendon loosening and reconstruction of the pulley was effected in the "arch" case using the type II technique.

DISCUSSION

When a flexor tendon lesion is found at the hand level, it is of the utmost importance to classify it in acute or chronic. If the acute lesions when treated have a better prognosis, the same does not happen with the chronic lesions which demand a more complex reconstruction, with a higher margin of unsatisfactory results. Among the chronic lesions, the worst as concerns prognosis are those with grade above 3, according to the Boyes⁽⁶⁾ classification. Most of the cases we treated are chronic lesions classified as grade 3 by this classification, thus, the worst cases.

As concerns the first surgical stage, we consider important a wide exposition of the injured finger volar region to assess the conditions of the remanescent pulleys; when this is not feasible we carry out the reconstruction of at least A2 and A4. In the absence of these pulleys, when the finger is flexioned, the already mentioned "arch" is observed as in patient number 19 (Figs. 16 to 19). For the reconstruction of a pulley we use a transverse strip of the extensor retinaculus of the carpus; when another pulley is necessary we use the superficial flexor of the injured finger. We observed that in the reconstructions where suture was made only at the borders of the remanescent shaft (type I), original technique described⁽¹¹⁾, good results were not a certainty. Thus, we made the reconstruction of the pulley with the ring form^(2,12) around the proximal and middle phalanges circumference. Thus, we obtained a more resistant new pulley avoiding the "arch" effect. The patients operated on according to type II presented better results, as patients number 5 — 5^th QDE, 9 — 3^rd QDD, 12 — 2^nd QDE, 15 — 3^rd QDD, 17 — 5^th QDD, 23 — 3^rd QDD, 23 — 4^th QDD, 23 — 5^th QDD, 24 — 2^nd QDD, 11 — 4^th QDD.

This technique is not used in thumb lesions since we believe that in these cases the transposition of the flexor superficial to the 4^th finger presents better results.

Only after a minimum period of 4 months the second stage was carried out, a basic pre-requisite being the total passive articular amplitude of the injured finger. In spite of individual differences, the orientations concerning the post-surgical rehabilitation process were uniformly made.

In relation to the second stage of reconstruction, we considered some important aspects leading to a more satisfactory final result. They are: type of graft, form of the distal fixation of the graft, motor unit to be used, suture tension to be maintained in the reconstructed tendon, and physiotherapy post-surgery.

As concerns the graft sources our priorities were the long palmar tendon, thin plantar and short extensor of the toes, in that order. The long palmar tendon offers more advantages and it is the most used. When more than one graft is necessary (case of two or more lesioned fingers), we obviously obtained grafts in other sites. Passage of the graft through the already prepared tunnel was the least traumatic possible with small incisions both at the wrist level and in the base of the finger distal phalanx.

As concerns the distal fixation of the graft we considered more secure to complement the suture with a "pull out" ⁽¹⁸⁾.

We must also consider the importance of the skin closure in the region of the distal suture before starting the proximal suture, since after the latter we will have difficulty to approach the finger volar region due to its flexed position. At the level of the proximal suture, we have no doubt that its realization in zone 5 is the factor with best prognosis than when it is effected in other level, since the adherence risk is smaller⁽⁵⁾.

After the tendon is cut retraction occurs not only of the tendinous segment but also and mainly of the muscular aspect. If at the moment of utilization we try to elongate it, it will not be possible to obtain the normal length; this will occur during the rehabilitation process. We consider this aspect the main cause of reconstructed tendon loosening. As concerns the choice of the motor unit we used the deep or superficial flexor of an adjacent finger. The utilization of the superficial flexor of a normal adjacent finger, in general de fourth finger, provides better results as concerns not losing tension during the rehabilitation process. Thus, we think that in case we use as motor unit the lesioned finger, the tension of the intra-surgery suture will be higher, and this will be observed in the greater flexion of the finger in relation to others in the rest position, contrary to the utilization of an adjacent tendon where we can adjust tension in order that the finger assumes a rest position similar to the anatomical.

The patients with loosening due to post-surgical loss of tension were submitted to another intervention to stretch, and we noticed that after surgery significant improvement was observed in three cases. Patients numbers 2 — 3^rd QDE, 2 — 4^th QDE, 10 — 3^rd QDE, show the importance of "regulating" tension during suture.

We also emphasize the importance of the physiotherapy post-operatively calling the attention to the position of the proximal interphalangeal articulations which must always be in position of complete extension (0º), since the retraction in flexion of the articulation can compromise the result.

We adopted WHI- TE's⁽²¹⁾ classification because it presents more complete parameters, making possible a better analysis of the results, though sometimes it is difficult to compare it with other less strict ones found in the literature,.

The flexor tendon reconstruction in chronic lesions a rescue operation⁽¹⁶⁾. When compared with the literature ^{(4,7,9,14,15)} our results have better means as concerns good results, probably because we use the above mentioned technical details (less incidence of bad results). Patient number 14 illustrates this (Figs. 20 to 24).

CONCLUSIONS

Reconstruction of flexor tendons in two stages can significantly improve the function of lesioned fingers presenting extense fibrosis or adherence of the flexor mechanism.

REFERÊNCIAS BIBLIOGRÁFICAS

Trabalho recebido em 08/10/2001. Aprovado em 28/03/2002

*Work performed at the Hospital Nossa Senhora do Pari - São Paulo - SP

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Publication Dates

• Publication in this collection
  02 Sept 2005
• Date of issue
  June 2002

History

• Received
  08 Oct 2001
• Accepted
  28 Mar 2002