Flexor tendon repair in zone 2C

FLEXOR

TENDON

REPAIR

IN ZONE

2C

J. B. TANG From the Hand Surgery Unit, Department of Orthopaedics, Ajfiliated Hospital of Nantong Medical College, Nantong, Jiangsu, China

A randomized prospective clinical study was carried out in 33 patients (37 lingers) with lacerations of both FDS and FDP tendons in the area covered by the A2 pulley, that is, zone 2C in Tang’s subdivision of no man’s land. Both lacerated tendons were repaired in 19 fingers and repair of only FDP with regional excision of FDS were performed in 18 fingers. Follow-up of average 12 months revealed that there was no significant difference in the end results evaluated according to the TAM system. The average TAM was 204” in the fingers with suture of FDP only and 187” in those with suture of both tendons. The fingers with suture of both tendons showed a higher rate of re-operation due to adhesions or rupture of repair. This study suggests that it is better to repair only FDP with regional excision of FDS when both tendons are injured in zone 2C. Journal of Hand Surgery

(British and European

Repair of both FDS and FDP tendons has been advocated for the purpose of improving functional recovery (Verdan, 1972; Kleinert et al, 198 1; Kleinert and Verdan, 1983). It is generally considered that repair of both tendons preserves the blood supply to the tendon of FDP through the vincular system, allows independent motion of the fingers and retains a smooth bed for the gliding of the profundus tendon. The flexor tendons surrounded by the A2 pulley are tightly constricted inside a rigid gliding tunnel, which is the narrowest for its gliding contents in zone 2. This corresponds to zone 2C in our subdivisions of Bunnell’s no man’s land (Fig 1; Tang, 1990; Tang and Shi, 1991; 1992). Although simultaneous repair of both tendons is generally thought k2Dw2C*2B*2Ad

Sub-zones

FDS

Volume, 1994) 19B: 72-75

to be advantageous in zone 2, the value of doing so specifically in each subdivision has not been studied. It is unknown whether the repair of both tendons in zone 2C is beneficial to the functional recovery of the fingers. This is a randomized prospective clinical study in 37 fingers of 33 patients with lacerations of both FDS and FDP tendons in zone 2C. The functional results of repair of FDP only with excision of FDS are compared with those of repairing both tendons. MATERIALS AND METHODS 37 fingers with division of both flexor tendons in zone 2C in 33 patients were included in this study. There were clean injuries without severe contamination, with complete transection of both flexor tendons, without bone and joint involvement, with damage to no more than one neurovascular bundle, and without complete destruction of the A2 pulley. Primary or delayed primary repair was done within 2 weeks after injury. There were 22 male and 11 female patients. Their ages ranged from 17 years to 47 years, with a mean of 34 years. 11 index, 14 middle, seven ring and five little fingers were involved. Both tendons were sutured in 19 and only FDP in 18, with excision of FDS. 20 fingers were repaired at the primary stage and 17 at the delayed primary stage. The cases left for delayed primary surgery were treated by debridement and skin closure primarily. During tendon surgery, all the patients were treated with the same operative procedure except for the treatment of FDS, and the same regime of post-operative mobilization was used for the patients. Operative procedures

Fig 1

Drawing illustrating Tang’s subdivisions of no man’s land. 2A: from the distal margin of the FDS insertion to the proximal margin of the insertion. 2B: from the proximal margin of the FDS insertion to the distal border of the A2 pulley. 2C: the area covered by the A2 pulley. 2D: from the proximal border of the A2 pulley to the proximal margin of zone 2.

The operations were performed under brachial plexus block and tourniquet control. A Bruner’s incision was used to extend the original laceration. The injured sheath was opened by an L-shaped cut or a flap in the digital sheath proximal to or through the proximal portion of the A2 pulley. The retracted proximal tendon ends were retrieved by flexion of all joints and by milking the

ZONE 2C TENDON

13

REPAIR

of both tendons, severe adhesions occurred, and tenolysis was performed 4 months after the initial tenorraphy. In the fingers with suture only of PDF, two fingers needed secondary tenolysis. Rupture of the repair occurred in one finger with repair of both tendons and a secondary tendon graft had to be used. The re-operation rate due to severe adhesion or rupture of the repair was 21.1% in the fingers with suture of both tendons and 11.1% in those with excision of FDS. The re-operation rate was higher in the fingers with repair of both tendons in zone 2C. Table 1 details the materials and final functional recovery of the patients who underwent re-operations.

palm. The location of the levels of division was confirmed by the location of the distal stumps of the tendons under the A2 pulley when the fingers were maintained in a neutral position. Both lacerated tendons were repaired in 19 fingers in 17 patients. Repair of FDP alone was performed in 1X fingers in 16 patients. FDP was repaired using two or three bands of Tsuge’s intratendinous suture (Tsuge et al, 1977; Tang and Shi, 1992). FDS was repaired with a double Tsuge suture. When FDS was not repaired, the tendon was excised in zone 2C, but not beyond the distal border of the A2 pulley. Partial lacerations of the A2 pulley were noted in 11 fingers, not requiring a reconstructive procedure. After release of the tourniquet, meticulous haemostasis was obtained before the skin was sutured. Post-operative

RESULTS

mobilization

The patients were treated by rubber band traction following the operation, as described by Kleinert et al ( 198 1). The hand was placed in a dorsal plaster cast with the wrist in 40” of flexion and the MP joints in a balanced position. With a rubber band attached to the fingertip under appropriate tension, the patients were instructed to perform active extension and passive flexion of the fingers for 3.5 weeks, at which time the dorsal plaster cast was removed and gentle passive finger flexion started. Rehabilitation usually continued for more than 3 months. Re-operations

Six fingers underwent re-operation because a satisfactory range of motion was not achieved following repair and subsequent rehabilitation. In three fingers with suture Table I-Patients NO.

Fingers

2 3

44, F 37, M 18, M

RIII RI1 LIV

4

24, M

5 6

30, F 21, M

*This was evaluated Table Z-Results

according

Timing of repair

Repaired tendons

Cause of failure

Re-operation

Recovery*

Delayed Delayed Delayed

FDP, FDS FDP FDP, FDS

Primary

FDP,

LII LIII

Primary Delayed

FDP, FDS FDP

Tenolysis Tenolysis Free tendon graft Tenolysis, FDS excision Tenolysis Tenolysis

Fair Good Poor

RIV

Adhesion Adhesion Rupture of repair Adhesion

to the TAM system proposed

by American

FDS

Adhesion Adhesion

Good Poor Fair

Society for Surgery of the Hand.

of flexor tendon repair in zone 2

Treatment

FDS repair FDS excision

The period of time between final surgery and review ranged from 5 months to 20 months with a mean of 12 months. The active flexion and extension deficit of the DIP, PIP and MP joints was measured, and the total active motion (TAM) was calculated (Kleinert and Verdan, 1983). The results were evaluated by TAM system recommended by the American Society for Surgery of the Hand (Kleinert and Verdan, 1983): normal TAM is rated excellent; TAM greater than 75% of the normal side, good; TAM greater than 50% of the normal side, fair; TAM less than 50%, poor, and less than before surgery, worse. In 19 fingers with FDS repair, the results in three were excellent, in nine were good, in four were fair, and in three poor. In 18 fingers with FDS excision, five rated excellent, eight good, four fair and one poor (Table 2). Fingers with excision of FDS showed better functional recovery than those with repair of both tendons (72.2% excellent or good versus 63.1%) but the difference was

undergoing re-operation

Age, sex

I

AND COMPARISON

Results

(no. and %)

Total no.

Excellent

Good

Fair

Poor

Worse

3(15.8) 5(27.8)

9(47.3) 8(44.4)

4(21.1) 4(22.2)

3( 15.8) l(5.6)

0 0

I9 18

14

Table 3-Results

THE JOURNAL

SURGERY

VOL. 19B No. 1 FEBRUARY

1994

of delayed primary tendon repair in zone 2

Treatment

Results Excellent

FDS repair FDS excision

OF HAND

0 2(25.0)

(no. and X)

Total no.

Good

Fair

Poor

Worse

4(44.4) 4( 50.0)

2(22.2) 2(25.0)

3(33.4) 0

0 0

not statistically significant. Excluding the case of rupture, the average TAM of all joints of the fingers with FDS excision was 204” compared to 187” in the fingers with repair of both tendons. The results were analyzed respectively in primary repair and delayed primary repair. This revealed no significant difference between the fingers with suture of both tendons and those with repair of only FDP for primary tenorraphy. In delayed primary repair, suture of both tendons gave excellent or good results in four out of nine fingers (44.4%), but excision of FDS gave excellent or good results in six out of eight fingers (75.0%; Table 3). Repair of FDS produced significantly worse results than FDS excision (rank sum test, P
The difficulty in achieving satisfactory function following the repair of divided flexor tendons in zone 2 is largely due either to the formation of severe adhesion or to rupture of the tendon repair. Excision of FDS in zone 2 has been shown to jeopardize vascular blood supply to the tendon of FDP through the connecting vincula, which adversely affects conditions for healing of FDP (Lundborg and Myrhage, 1977; Matsui et al, 1979). It has therefore been considered better to repair both tendons rather than only FDP (Lister et al, 1977; Kleinert et al, 1981). However, some surgeons have prefered to excise FDS (Tsuge et al, 1977; Schneider et al, 1977). Lister et al (1977) reported that 21 of 28 (75%) of the patients with tendon repairs in no man’s land attained excellent or good results evaluated using the TAM system. In those where FDS had been excised, there were some poor results, only three out of seven (42.9%) being excellent or good. The excellent or good results for patients in whom all tendons were repaired comprised 18 out of 21 fingers (85.7%). Nielsen and Jensen (1984) reported that when both tendons were repaired in 35 fingers and FDS was excised in 32, 74% of fingers with suture of both tendons attained an excellent or good result evaluated by using the method of Buck-Gramcko, but only 47% in those of FDP alone did so. Tsuge et al (1977) excised FDS when it was damaged completely, giving excellent or good results in 24 out 34 patients using the White’s criteria. In a report of delayed primary repair by Schneider et al (1977), all the FDS tendons were excised except in one finger. Among 31 fingers with both flexor tendons severed in

9 8

no man’s land, eight fingers (36%) had a TAM of 220”, and in 10 fingers (32%) it was between 200” and 220”. Repair of FDP only or both tendons was reported to have given an equivalent result by Brunelli et al (1983). A comparative clinical survey made by Ikuta and Tsuge (1985) revealed no relationship between the procedure used for FDS and the result. The gliding tunnel of the digital flexor tendons varies in shape and diameter within zone 2, and it is at its narrowest in the area covered by the A2 pulley. On an anatomical basis, Tang (1990) postulated the concept of subdividing Bunnell’s no man’s land into four subdivisions, and addressed the potential necessity and benefits of primary tendon repair according to the subdivisions. The specific area covered by the A2 pulley is designated as zone 2C. The flexor tendons within zone 2C are tightly restricted by the largest and the most rigid annular pulley (A2). FDS bifurcates into two obliquely coursed tendinous slips at the midportion of this area. The volar blood supply in the FDP tendon decreases sharply at the border of the A2 pulley and an avascular area is present in the central portion of this tendon segment, which makes the tendon of FDP in zone 2C comparatively ischaemic and poorly perfused (Ochiai et al, 1979; Tang, 1990). The gliding surface of the A2 pulley is devoid of blood vessels, and chondrocyte-like cells are present in the superficial areas of the gliding surfaces of either the A2 pulley or the profundus tendon (Lundborg and Myrhage, 1977). The lack of vascular plexus and cartilaginous differentiation in both the pulley and the tendons indicates that the flexor system in this area is subjected to great compression forces. Considering the anatomical and biomechanical features of zone 2C, we have recommended that the indications for FDS excision should be widened in zone 2C (Tang and Shi, 1992). Subsequently, Hu et al (1993) carried out an experimental study to verify our clinical suggestion. Their experimental study demonstrated that primary repair of both tendons in a clean-cut chicken model does not produce a superior gliding excursion of FDP to that resulting from repair of FDP and excision of the FDS. Flexion of the toes with repair of both tendons was significantly worse 8 weeks after surgery than that following excision of FDS. The experiment further revealed that repair of both tendons inside this rigid fibro-osseous tunnel led to poorer tendon healing and an increase in the rupture rate. The present report compares the results following two methods of management of FDS in a randomized pro-

ZONE 2C TENDON

75

REPAIR

spective clinical study. It was showed that repair of both tendons does not improve the TAM of the fingers, and it increases the number of fingers with severe adhesions or tendon rupture. Repair of both tendons in delayed primary surgery worsens the results significantly. These findings support the idea of widening the indications for excision of FDS in zone 2C. Repair of FDP alone with regional excision of FDS simplifies the operative procedure and reduces the number of tendon sutures inside the sheath, Furthermore, it eliminates the possibility of adhesions between the two repaired tendons. On the other hand, excision of FDS within zone 2C does not damage the vincular system of the tendons, since the attachments of the vincula in FDS are distal to the A2 pulley (Matsui et al, 1979; Zhang et al, 1991; Tang and Shi, 1992). Excision of FDS, if not extended distally to zone 2B, does not influence the blood supply to FDP. In delayed primary repair, lacerated tendons become oedematous and the tendons retract more proximally. Tension sutures of both tendons in a tightly restricted sheath tunnel causes compression between the rigid A2 pulley and the oedematous tendons, which may initiate a series of pathophysiological changes similar to compartment syndrome in the extremities The poor tendon healing, worse gliding functions and destruction of the synovial sheath resulting from an insufficient inner sheath space for the corresponding tendons has been termed the ‘digital sheath syndrome’ (Tang et al, in press). The A2 pulley is the most important pulley preventing bowstringing of the tendons, and thus it can not be opened or enlarged by a graft as we have reported (Tang et al, 1993). Therefore, repair of FDS in zone 2C is not recommended during delayed primary surgery. References BRUNELLI, G., VIGASIO, A. and BRUNELLI, F. (1983). Split-knot flexor tendon suture in zone II allowing immediate mobilization. The Hand, 15: 3: 352-358. HU, Q.$ WANG: S. H. and HU. Q. (1993). Adhesion formation following primary tendon repair in zone IIc. An experimental study. Chinese Journal of Hand Surgery, 9: 1: 32-35.

IKUTA.

Y. and TSUGE, K. (1985). Post-operauve wult? of looped nylon injuries of the digital flexor tendons. Journal of Hand Surgery, 10B: 1: 61.-72. KLEINERT: H. E., SCHEPEL, S. and GILL, T. (1981). Flexor tendon injuries. Surgical Clinics of North America, 61: 2: 267-286. KLEINERT.> fT. E. and VERDAN, C. (1983). Report of the committee on tendon mJuries. Journal of Hand Surgery, 8: 5: 7944798. LISTER, G. D., KLEINERT, H. E.; KUTZ, J. E. and ATASOY, E. (1977). Primary flexor tendon repair followed by immediate controlled mobilization. Journal of Hand Surgery, 2: 6: 441-451. LUNDBORG, G., and MYRHAGE, R. (1977). The vascularization and structore of the human digital tendon sheath as related to flexor tendon function. Scandinavian Journal of Plastic and Reconstructive Surgery, 11: 195-203. MATSUI, T., MERKLIN, R. J. and HUNTER, J. M. (1979). A micro-vascular study of the human flexor tendons in the digital fibrous sheath. Journal of Japanese Orthopedic Association, 53: 307-320. NIELSEN, A. B. and JENSEN. P. 0. (1984). Primary flexor tendon repair in “no man’s land”. Journal of Hand Surgery. 9B: 3: 279-281. OCHIAI, N., MATSUI, T.. MIYAJI, N., MERKLIN, R. J. and HUNTER, J. M. (1979). Vascular anatomy of flexor tendons. I. Vincular system and blood supply of the profundus tendon in the digital sheath. Journal of Hand Surgery, 4: 4: 321-330. SCHNEIDER, L. H.. HUNTER, J. M., NORRIS, T. R. and NADEAU, P. 0. (1977). Delayed flexor tendon repair in no man’s land. Journal of Hand Surgery, 2: 6: 452-455. TANG, J. B. (1990). Subdivisions of “no man’s land”. Presented at the Fourth Meeting of Chinese Society for Surgery of the Hand. Wuxi; Jiangsu. TANG. J. B. and SHI. D. (1991). Subdivisions of “no man’s land” of the digital flexor tendons and different management of tendon injuries in subdivisions. Chinese Journal of Surgery. 29: 10: 608-611. TANG. J. B. and SHI. D. (1992). Subdivision of flexor tendon “no man’s land” and different treatment methods in each sub-zone: A preliminary report. Chinese Medicai Journal. 105: 1: 60-68. TANG, J. B., ZHANG. Q. G. and ISHII, S. (1993) Autogenous free sheath grafts in reconstruction of injured digital flexor tendon sheath at the delayed primary stage. Journal of Hand Surgery, 18B: 1: 31-32. TANG, J. B., ISHII, S., USUI. M. and YAMAMURA: T. Flexor sheath closure during delayed primary tendon repair. Journal of Hand Surgery (American Volume; in press). TSCGE, K., IKUTA, Y. and MATSUISHI, Y. (1977). Repair offlexor tendons by intratendinous tendon suture. Journal of Hand Surgery, 2: 6: 436-440. VERDAN, C. E. (1972). Half a century of flexor-tendon surgery. Current status and changing philosophies. Journal of Bone and Joint Surgery, 54A: 3: 472-491. ZHANG, 2. Z., ZHONG, S. Z. and SHUN, 8. (1991). Blood supply of flexor tendons through vincula: An experimental study. Chinese Journal of Hand Surgery, 7: 1: 40-42.

sutureusedin

Accepted: 16 June 1993 Jin-bo Tang, MD, PhD Associate Professor, of Nantong

Medics1

College,

20 West Temple

a 1994 The British Society for Surgery

Department of Orthopedics, Affiliated Hospital Road, Nantong 22600!. Jmngsu, China.

of the Hand