OPPONENSPLASTY DIGITORUM

BY EXTENSOR INDICIS SUPERFICIALIS TENDON

G. A. ANDERSON,

V. LEE

AND FLEXOR TRANSFER

and G. D. SUNDARARAJ

From the Christian Medical College & Hospital, Vellore, India From 1977 to 1988, 166 patients with median nerve paralysis of varied aetiology underwent opponensplasty. In 50 of these the extensor hnlicis was used, and in 116 the flexor digitorum superficialis of the ring finger. An analysis of these hands showed that the EI opponeusplasty was best in supple hands and FDS opponensplasty was more suitable for less pliable hands. There were fewer complications seen after FDS opponensplasty if the detachment of the donor tendon was done through a volar oblique incision rather than the conventional lateral incision. Journal of Hand Surgery (British Volume, 1992) 17B : 611-614 Table l-Conditions

Many techniques have been described for restoration of opposition in the paralysed thumb. This study was carried out with the objectives of finding specific indications for using the flexor digitorum superficialis tendon or the extensor indicis tendon for opponensplasty. Two different methods of detachment of FDS have been used, and the results of these compared. OPERATIVE

Aetiology

EI Opponensplasty group Hansen’s disease Trauma Poliomyelitis Burns Congenital

TECHNIQUES

In EI opponensplasty the method of tendon transfer was similar to that described by Burkhalter in 1973, but with varied points of insertion (Anderson et al, 1991). In the FDS opponensplasty two techniques were used. One was a modification of Brand’s transfer (1952) described by Fritschi (1971), in which a lateral skin incision was used to detach the FDS tendon. The other was a refinement of Fritschi’s technique using a volar oblique Bruner skin incision for direct visualization of the tendon. This also minimizes the risk of injury to the lateral bands of the extensor expansion and the profundus tendon. MATERIAL

AND

causing loss of thumb opposition Type ofparalysis

Total

High median

Law median

2 6 5

21 14 2 1

-

FDS Opponensplasty groups Hansen’s disease Trauma

113 11

23 20 5 2 1 51

113 11 124 -

Grade III : A stiff hand with a thumb web angle less than 25”. Callosities and absorption of digits both present; passive opposition of the thumb not full. Following assessment, supervised physiotherapy was started. This included wax baths, oil massage, passive stretching of contractures and muscle strengthening exercises. Once maximum possible correction of the contractures had been achieved, the patient was admitted for surgery. Grade III hands required more pre-operative physiotherapy than hands in grades I and II (Table 2). The criteria for selection of the operation depended on the availability of the motor, the occupation of the patient, the grade of the hand and the overall requirements of the hand. Post-operatively all hands were immobilized in plaster of Paris casts. After three weeks the plaster and sutures were removed and supervised physiotherapy commenced. This consisted of active mobilization and re-education of the transferred tendon. As soon as the patient could actively oppose the thumb to the middle finger (usually at the end of the second week of physiotherapy), occupational therapy was given for a week. At the end of this period the patient was reassessed and discharged. The minimum follow-up period was 12 months. 14 patients (14 hands) were lost to follow-up (Table 3).

METHODS

All the 175 hands of 166 patients who underwent opponensplasty during the years 1977 to 1988 were considered for this study. These hands were divided into three groups, EI opponensplasty, FDS transfer with detachment through a lateral incision, and through a volar skin incision. The conditions causing loss of thumb opposition are shown in Table 1. Pre-operative evaluation included a detailed general assessment, motor examination using the Medical Research Council grading, and sensory testing with a wisp of cotton wool and 5/O nylon. Mobility, stability and angles of contracture of joints were recorded and hands graded into three categories. Grade I : A supple mobile hand with a thumb web angle of 35” or more, no absorption of digits and full passive opposition of the thumb. Grade II : A mobile hand with a thumb web angle of 25” to 34”, few callosities and no absorption of digits. Full passive opposition of the thumb. 611

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of physiotherapy before operation

Grade

I II III

-EI

FDS lateral

No.

Range

Mean

SD

No.

Range

Mean

36 10 5

3-10 7-30 15-35

5.7 14.4 22.6

+1.74 + 7.23 k9.29

12 19 50

3-8 3-28 5-71

5.0 9.4 19.4

FDS volar SD + 2.22 f 6.82 * 12.80

No.

Range

Mean

4 16 23

3-5 4-24 7-63

3.8 10.1 22.1

SD + 0.96 f. 6.05 f 12.56

(For grades see text)

Table 3 Donor tendon for detachment (Total) Number Number

of patients of hands

Age (years) Hands followed up Follow-up period (months)

166 175 Range 6-44 161 Range 12-66

EI

FDS lateral

FDS volar

50 51 Mean 25.4 46 Mean 30.8

74 81 Mean 30.1 75 Mean 29.3

42 43 Mean 30.2 40 Mean 24.2

SD f 8.97

Range 9-60

SD + 14.66

Range 12-132

Assessment of restoration of thumb opposition was based on a modification of the criteria outlined by Sundararaj and Mani (1984). Thumb opposition to tip of ring or little finger with IP joint of thumb extended and more than 70% of thumb function restored. Good: Thumb opposition to tip of index or middle finger with IP joint of thumb extended and more than 50% of thumb function restored. Fair: Thumb opposition with flexion of its IP joint, and less than 50% of thumb function restored. Poor: No opposition. Excellent:

RESULTS Looking at the overall results (Table 4), the groups are comparable. The EI group has 89.1% excellent and good results, whereas the FDS groups have 85.2% and 85.0% excellent and good results. Both EI and FDS have around 2% poor results. However, a higher percentage of excellent results is found after EI transfer than after FDS transfer.

SD + 10.90

Range 12-56

SD + 28.54

Range 12-93

SD f 11.93 SD k21.75

After FDS transfer, limitation of extension of the donor ring finger may be seen as a result of damage to the lateral bands of the extensor expansion while detaching the superficialis tendon (Fig. 1). This was seen in 33 hands where the tendon was detached through a lateral incision and eight hands where the same was done through a volar incision (Table 5). Another complication encountered after FDS transfer was a flexion contracture of the PIP joint of the donor ring finger (Fig. 1). This was seen in six hands. This is probably due to the remaining tags of the FDS tendon becoming adherent to the fibrous flexor sheath and thus limiting full extension. A third complication seen was the radial migration of the transferred tendon in the region of the wrist; this was frequent, being seen in 34 hands. This is probably due to stretching of the radial wall of Guyon’s canal. However, in none of these 34 hands has there been any deterioration of the result of the opponensplasty when the early postoperative result was compared with that found later. Thus radial migration of the transferred tendon does not interfere with the function of opposition. DISCUSSION

Complications

Various complications have been described. After EI transfer, an extensor lag of the index finger at the metacarpophalangeal joint is seen if the extensor expansion is not repaired carefully (Burkhalter 1973). The fascia used as a pulley situated just anterior and distal to the pisiform may stretch. Pulleys are said to stretch with time (Sakellarides 1970). None of these complications was seen in our series.

Technically both operations demand similar precautions and care, but EI opponensplasty is more exacting. Care must be taken to take a small portion of the extensor expansion along with the tendon or it may be too short. After detachment, the extensor expansion must be repaired carefully to avoid extensor lag of the index finger. In FDS opponensplasty, the dissection should not be taken too far laterally while detaching the donor tendon to avoid damage to the lateral bands of the

OPPONENSPLASTY

WITH

EI AND

613

FDS

Table 4-Results FDS lateral

EZ -

Overall

results

According of hand Adjuvant

to grade

surgery*

Aetiology

No.

E

G

F

P

39 84.7

2 4.4

4 8.8

1 2.2

1 1 l--

2 2

-

7 II III Nil + 1 procedure > 1 procedure Hansen’s Others**

32 6 1 :: 2 16 23

1

3 1 3 1

1 2

1 1 -

FDS

volar

E

G

F

P

E

G

F

11

47 62.6 210 35 2 42 3 43 4-

9 12.0

2 2.6

17 42.5 2 11 4 4 10 3 17

17 42.5 1 3 13 3 12 2 17

6 15.0

-

1 5

-

5 1 6

~

22.6 9 6 2 4 10 3 11 6

9

2

8 1 9

2

-

2

P

E=excellent G=good F=fair P=poor. * Claw correction, web plasty, IP fusion of thumb, etc ** Injury, polio, bums, congenital.

Table 5-Complications FDS NO.

DIP extension lag PIP flexion contracture Radial migration of transferred tendon

33 6 20

FDS

lateral

%

44.0 8.0 26.6

No.

uolar

%

8

20.0

14

35.0

extensor expansion leading to inadequate extension of the DIP joint of the ring finger. The volar incision permits direct visualization of the FDS tendon without the need to carry the dissection laterally. Detachment of FDS decreases power grip, but we have not measured this. The power of the motor should be enough to restore anteposition but not to prevent adduction. In the supple hand EI has produced good results. In a stiffer hand, we feel that a stronger force is needed to overcome the rigid tissue and prevent recurrent contracture. FDS provides this powerful force and the nature of the Y-insertion creates a balance between abductidn and pronation. The line of action of the EI transfer is more direct than that of FDS with the apex of angulation of the transferred tendon being just anterior to the pisiform. In the FDS transfer, the line of action of the tendon angulates with its apex at Guyon’s canal. This smaller angle means that the transferred FDS has to perform more work than EI to produce the same force at its point of insertion. This was verified on cadaver hands, where 43% more force was required to initiate opposition in the FDS route of transfer than in the EI route. Various insertions have been used in this series. The type of insertion used did not seem to affect the results provided the anchorage was sound.

Fig. 1

FDS opponensplasty at follow-up, with DIP flexion of the ring finger and radial migration of the transferred tendon.

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CONCLUSIONS

We feel that FDS may give better results in stiffer hands, but more mobile hands do well with EI opponensplasty. The volar oblique incision offers clear visualization when detaching the FDS tendon, reducing the incidence of flexion deformity of the ring finger. Acknowledgement

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BRAND, P. W. (1952). Reconstruction of the hand in leprosy. Annals of the Royal College of Surgeons of England, 11: 350-361. BURKHALTER, W., CHRISTENSEN,R. C. andBROWN, P. (1973). Extensor indicis proprius opponensplasty. Journal of Bone and Joint Surgery, 55A: 4: 725-732. FRITSCHI, E. P. Reconstructive Surgery in Leprosy. Bristol, John Wright and Sons, 1971: 86-89. SUNDARARAJ, G. D. and MANI, K. (1984). Surgical reconstruction of the hand with triple nerve palsy. Journal of Bone and Joint Surgery, 66B: 2: 260264. SAKELLARIDES, H. T. (1970). Modified pulley for opponens tendon transfer. Journal of Bone and Joint Surgery, 52A: 1: 17X%179.

The authors wish to thank Mr K. Mani, Biostatistician, and Mr A. Jayavelu, Computer Programmer, for their invaluable help in the preparation of this manuscript.

References ANDERSON, G. A., LEE, V. and SUNDARARAJ, G. D. (1991). Extensor indicis proprius opponensplasty. Journal of Hand Surgery 16B: 3: 334-338.

Accepted in revised form: 17 December 1991 Professor G. A. Anderson, Christian Medical

College

India.

0 1992 The British Society for Surgery of the Hand

and

Hospital,

Vellore-632004,

TN,