Abstract
Background
Various combinations of tendon transfers are available for radial nerve palsy. However, the choice of which set of transfer to be performed in a patient remains an issue of varied opinions among surgeons. The study attempts to evaluate the results of various tendon transfers for radial nerve palsy quantitatively and subjectively. It also identifies which set of transfer is suitable for particular groups of patients.
Materials and methods
The study was conducted between 2005 and 2007. A total of 15 tendon transfers were performed using various combinations and evaluated according to Bincaz’s criteria, Kapandji scale and effect of tendon transfers on activities of daily living.
Results
13 patients had excellent to fair outcome according to Bincaz’s criteria. 2 patients had poor outcome. There was no hindrance in the activities of daily life in all patients. 93.4% of patients were satisfied with the results.
Conclusion
Every combination of tendon transfers has its own set of merits and demerits. Selection of donor tendons as per occupational need of patients is utmost important. Patients in our series were satisfied with set of transfers using Pronator teres(PT) for wrist extension, Flexor carpi radialis (FCR) for finger extension and rerouted Palmaris longus (PL) for extension of thumb. Flexor carpi ulnaris (FCU) is important for power grip.
Keywords: Radial nerve palsy, Tendon transfer, Bincaz criteria, Kapandji scale, Flexor carpi ulnaris, Flexor carpi radialis
1. Introduction
The hand is an organ of grasp as well as fine movements. It is useful in activities of daily living. It is also useful in all type of occupations ranging from precise fine work of jeweler to hard work of labourer’s. The importance of hand is due to its prehensile function.
According to Riordan,1 grip has three phases – phase 1 is opening the hand widely, phase 2 consist of surrounding the object, phase 3 is gripping the object between the finger and the palm.
Radial nerve innervated muscles have an important role in phase 1 and phase 3 of grip and also play role in release of grasped objects.
Injury to the radial nerve leads to loss of wrist and finger extensors, thus destroying the essential action of normal grasp and release pattern. Although the results of neurorrhaphy of radial nerve are favorable, but when this is not possible, functional restoration is possible through tendon transfers.
There are various types of tendon transfers available, each having its own merits and demerits. There are only a few studies comparing the results of these tendon transfers. It is well known that FCU has twice the power of wrist flexion than FCR with similar excursion. For grasp and release function, opening of MCP joint is more important than the power of extension. This opening is related directly to the excursion of transferred tendon than the power. So, the controversy regarding which tendon to use as donor should be resolved on the basis of effects of using a tendon on hand function. Also, harvest of FCU requires exposure of 2/3rd of ulnar forearm. FCR on the other hand can be harvested with a much smaller incision. FCR can be used through interosseous membrane route without much risk of adhesion formation. FCU on the other hand is transferred subcutaneously which results in a visible swelling around the ulnar border. Therefore, we propose to study the functional results of various tendon transfers in local population as per their demands and occupation, to analyze advantages and shortcomings of various procedures and justification of one tendon transfer over the other.
2. Materials and methods
It is a prospective study of tendon transfers in radial nerve palsy between May 2005 to November 2007 at tertiary care center. The study comprised of 15 patients: 12 of high radial nerve palsy and 3 of low type radial nerve palsy. There were 14 male patients and 1 female patient.
For wrist extension, pronator teres was used as donor in 12 high radial nerve palsy cases. For finger extension, FCR (by interosseous route), FCU (by subcutaneous route), FDS or ECRL were used.
PL was used for thumb reconstruction and when it is not available, FCR or FDS (3 and 4) were used. In all cases rerouting of EPL was done.
The extremity was immobilized in above elbow slab for 3 weeks after surgery. Post operative mobilization was started at 3 weeks. Intermittent passive mobilization of all immobilized joints was carried out for a week. Short cock up splints for day and long cock up splints at night were used (Fig. 1). Reeducation of transferred tendon was started once joints were mobile. Light activities as taking off lids, eating food, light self care activities, writing with soft pencil were allowed when grade 2 power of transferred wrist tendon was achieved. Daytime splinting was discontinued when grade 3 power was restored. Moderate activities as computer activities, holding water glass were allowed when power improved to grade 4. Strenuous activities as twisting, squeezing, screwing are not allowed till patient starts holding MP joint neutral with wrist in functional position of about 10–20 dorsiflexion. This is also the time to discontinue the night splint. The patients were followed for a mean duration of 14 months.
Fig. 1.
Long and short cock up splints.
Criteria for final assessment was as proposed by Bincaz et al.2 (Table 1).
Table 1.
Bincaz’s criteria.
| Points | 3 | 2 | 1 | 0 |
|---|---|---|---|---|
| Wrist extension | >29° | 0–29° | <0° | |
| MCP Joint extension | Full | Extension loss <10° | Extension loss >10° | |
| First web space opening | >39° | 0–39° | <30° | |
| Patient satisfaction | Excellent | Good | Fair | Bad |
According to scoring system (Table 2).
Table 2.
Scoring system.
| Excellent | Greater than or equal to 8 |
|---|---|
| Good | 6–7 |
| Fair | 4–5 |
| Bad | <3 |
Opposition of thumb was measured using Kapandji scale (Table 3).3
Table 3.
Kapandji scale.
| Kapandji Scale | |
|---|---|
| When the thumb can pinch to the lateral side of the second phalanx of the index finger | 1 |
| for pinch to the lateral side of the distal phalanx of the index finger | 2 |
| for pinch to the tip of the index finger | 3 |
| for pinch to the tip of the middle finger | 4 |
| for pinch to the tip of the ring finger | 5 |
| for pinch to the tip of the little finger | 6 |
| When it touches the distal interphalangeal joint crease | 7 |
| When it touches the proximal interphalangeal joint crease | 8 |
| When it touches the basal crease of the little finger | 9 |
| When it reaches the distal palmar crease | 10 |
3. Results
In our study, a total of 15 tendon transfers were performed in 15 patients. All the patients were below 50 years of age with 14 patients below 30 years. The most common injuries causing radial nerve palsy were fracture shaft of humerus and supracondylar fractures of humerus along with crush injuries around the elbow. In our study, the non dominant extremity was affected in 60% of patients. 12 cases were of high radial nerve palsy whereas 3 cases were of low radial nerve palsy.
Pronator teres was used for wrist extension in all patients with high radial nerve palsy. In 2 patients, flexor carpi ulnaris was used for finger extension, in one patient, flexor digitorum superficialis of third and fourth finger was used while in the remaining patients, flexor carpi radialis was used.
For low radial nerve palsy ECRL was used for one patient for finger extension, while in the remaining 2 patients, FCR was used.
For thumb reconstruction, palmaris longus was used in 14 patients and flexor carpi radialis was used in a single patient.
The following tables summarize the results of transfers (Table 4, Table 5 and Fig. 2, Fig. 3)
Table 4.
Wrist extension.
| Active wrist extension | No. of patients | Percentage |
|---|---|---|
| Less than 0° | 0 | 0 |
| 0–29° | 11 | 72.6 |
| More than 29° | 4 | 27.4 |
Table 5.
First web space opening.
| First Web Space Opening | No. of patients | Percentage |
|---|---|---|
| Less than 30° | 4 | 27.4 |
| 30–39° | 11 | 72.6 |
| More than 39° | 0 | 0 |
Fig. 2.
Extension loss at MP Joint.
Fig. 3.
Patient satisfaction.
Comparison of results According to Bincaz score (Table 6, Table 7).
Table 6.
Results according to Bincaz’s Score.
| Bincaz Score | No of Patients | Percentage |
|---|---|---|
| 8 or more (Excellent) | 6 | 39.6 |
| 6 or 7 (Good) | 4 | 26.4 |
| 4 or 5 (Fair) | 3 | 20 |
| 3 or less (Bad) | 2 | 13.3 |
Table 7.
Results according to Kapandji scale.
| Kapandji Scale | No of Patients | Percentage |
|---|---|---|
| 7 or < 7 | 04 | 26.4 |
| 8 | 02 | 13.2 |
| 9 | 02 | 13.2 |
| 10 | 07 | 46.2 |
| Total | 15 | 100 |
Patient’s Opinion about recovery of ADL (Table 8).
Table 8.
Effects on ADL.
| Effect on ADL | No. of Patients | Percentage |
|---|---|---|
| 0 (Hinders Function) | 0 | 0 |
| 1 (Disturbing) | 3 | 20 |
| 2 (Moderate) | 9 | 60 |
| 3 (Minor) | 3 | 20 |
4. Discussion
Restoring function to paralyzed extremity has always been a challenge. Palsy following injury to radial nerve also poses such a challenge.
Since the development of the idea of transferring available tendons to substitute the paralyzed ones by Nicoladoni4 in 1880, this method of restoring functions has come a long way.
One of the earliest descriptions of tendon transfer in radial nerve palsy was reported in 1899 where Franke5 transferred FCU to EDC. In the same year, Capellen5 reported transfer of FCU to EDC and PL to EPL. In the past 100 years, over 60 techniques for tendon transfers have been described for radial nerve palsy.
Use of PT for wrist extension as proposed by Jones6 and PL for thumb has become almost universally acceptable. With so many available options, major controversy exists between use of FCU or FCR for finger extension. Our study is to evaluate and compare results between different sets of tendon transfers.
5. Restoration of wrist functions
Re-establishment of wrist extension is probably the most important aspect of tendon transfer surgery. PT universally remains the donor of choice because it’s force (1.2 Kg) is somewhat superior to individual force of ECRL or ECRB, even though their excursion is only slightly greater than PT.7 Our series constituted 12 cases of high radial nerve palsy and 3 cases of low radial nerve palsy. We preferred to transfer PT to more centrally located ECRB in all cases of high radial nerve palsy. 9 of these cases had no radial deviation during wrist extension, but in 3 cases, there was radial deviation of less than 10°. These findings can be explained by the fact that in some patients, there are intermuscular adhesions between ECRL and ECRB (Fig. 4, Fig. 5). Some tendinous interconnections were also seen.8 Through this observation, we have made it a practice to look for these adhesions or interconnections prior to performing this transfer.
Fig. 4.
Showing intertendinous connection between ECRL and ECRB.
Fig. 5.
Radial deviation at wrist with dorsiflexion.
In two of our cases of low radial nerve palsy, we encountered more than 15° of radial deviation. This can be explained due to solitary action of ECRL. In one case of low radial nerve palsy, we used ECRL for finger extension because ECRB had recovered. One realization can be made from the above finding that contrary to traditional thinking of leaving the wrist in low radial nerve palsy, it may be judicious to centralize ECRL.9
6. Restoration of finger extension
The choice of transfer is more difficult for restoration of finger extension. Three donor options are usually considered – FCU, FCR, FDS. FCU and FCR are most commonly used. The choice between these two tendons remains controversial. FCU is the stronger flexor of the wrist, having twice as much as power as compared to FCR. This quality is however offset by two consequences – first loss of ulnar deviation during power grasp and second, due to loss of wrist strength. In cases of low radial nerve palsy, it is not advisable to use FCU, because it may result in significant radial deviation due to unopposed power of ECRL.10,11
Excursion and power of FCR is slightly less than EDC. FCR use maintains neutral equilibrium of the wrist in both frontal and sagittal planes.9
In the present series, 12 cases were of high radial nerve palsy and 3 were of low radial nerve palsy. In 2 cases of low radial nerve palsy FCR was used as donor for finger extension while in a single case ECRL was used. This was done because ECRB had already shown recovery. In this case ECRL was used as its excursion is greater than EDC. There is an additional advantage of making the transfer monophasic, which is advantageous in post-operative rehabilitation.
In high radial nerve palsy, FCU was used as donor for finger extension in 2 cases while FCR was used in remaining 9 patients who were from rural background with occupation requiring power grip. In one patient FDS of third and fourth finger was used donor for finger extensor.
In two cases where FCU was used, both felt weakness of wrist during activities such as opening a big size tight jar and holding large object as plate in palm which simultaneously requires extension of metacarpophalangeal and strong ulnar deviation of wrist. This can be explained by the fact that FDS and FDP not only assist in stabilizing the wrist after FCU transfer, they can produce significant ulnar deviation. Without finger flexion, the ability of ulnar deviation was limited. However, most daily activities and work performance rarely require isolated wrist motion without digital flexion.12
In patients in whom FCU was used for finger extension, ulnar deviation of wrist during power grip was only 10° in one patient. In the second patient, there was no ulnar deviation, however, the wrist was stable even in neutral position during power grip. Due to this reason these patients had difficulty in ‘dart movements’ of the wrist. This may be troublesome in some occupations such as mechanics and carpenters.
The use of middle and ring finger superficialis described by Boyes (1960) is another donor of choice for MCP joint extension. The intrinsic qualities of this transfer are excellent because these two tendons are stronger than EDC and have greater excursion. However, disturbance of autonomy of finger flexion may pose difficulty in computer operators and artisans. Kruft et al. (1997) felt that post operative rehabilitation is longer and more difficult with this transfer.13 In our series where FDS of middle finger was used as donor, the patient was able to achieve good finger extension.
7. Problem of extensor lag
8 of the patient were having extensor lag at metacarpophalangeal joint after finger extension transfer in our series. It was a significant number. There were 6 patients where FCR was used, 1 patient in whom FCU and in another FDS was the donor. The patient in whom FCU was used and showed extensor lag had a recovered FCU due to affection of ulnar nerve around elbow after a crush injury. In the remaining 7 patients (in 6 FCR was the donor and in one FDS was the donor), where extensor lag developed, were analysed. As their follow up was of only 3 months and extended use of night long cock up splint was recommended. We discussed the issue in Hand clinic with occupational therapist. Wrist extensor transfer gains power earlier than finger extensor transfer. Once patient starts using hand for daily activities especially some twisting and strenuous activities after gaining grade 3 power in wrist transfers, development of finger extensor delays further. So in subsequent patients we explained them about this. Strenuous activities as twisting, squeezing were not allowed up to the time sufficient development of finger extensors. Night long cock up was also continued up to that time. After that extensor lag problem was solved.
In conclusion, FCR was the donor of choice for finger extension in this series because it’s power and excursion are only slightly less than EDC, it’s route of transfer through interosseous membrane is straighter than subcutaneous route of FCU and we have not encountered problem of adhesion. FCU as a strong wrist flexor with important role in power grip should be left in its place.
8. Restoration of thumb functions
The goal of transfer to the thumb is as much opening of first web space as retroposition of thumb. EPL is an extensor and adductor of the thumb and when rerouted radially from Lister’s tubercle in line of first extensor compartment through the anatomical snuff box, becomes extensor and abductor of thumb. Our donor of choice was PL in 13 cases. In one case, PL was transferred to APL and EPB as patient had suffered amputation through IP joint. In one case with absent PL, FCR was used for EPL.14
In 72.6% of cases, first web space opening was more than 30°. And in 27.4% cases, less than 30°. In four of our patients, there was palmar abduction instead of radial abduction which can be explained by slight volar subluxation of the transferred tendon (Fig. 6, Fig. 7). In these cases, hyperextension at MP joint was seen on attempted extension due to over powering of thumb adductor. Hence, we recommend that the rerouted EPL should pass along the direction of first extensor compartment to provide greater radial abduction. Use of EPB pulley as described by Tsuge may be useful in preventing volar subluxation.5 In all cases of PL to EPL transfer, bowstringing of transferred tendon was noted (Fig. 8), however, except cosmesis no functional problems were seen.
Fig. 6.
Volar route of transfer showing palmar abduction.
Fig. 7.
Route of transferred tendon along first compartment.
Fig. 8.
Bowstringing of transferred tendon.
Mean abduction of thumb was 30° and opposition was 8.8 (range 7–10) according to Kapandji scale.3 These findings are consistent with series of M. Ropras.9 However, in that series, mean abduction was 54° which is not so in our case.
The following observations were made in terms of functional outcome –
-
•
One patient with FCU transfer complained that he could not write long words with many letters. This was supposed because of reduced ability for ulnar deviation at the wrist and the final letters of the word became crowded.
-
•
Inability to hold heavy objects for a long time due to weakness of wrist as a result of using one flexor of wrist as donor.
-
•
Labourers in whom FCR was used were satisfied with their wrist stability and power and performed their activities normally.
We had a single complication in the case series. The patient developed foreign body granuloma at PL to EPL juncture site. This was managed by removal of polypropylene suture after healing of juncture.
Every combination of tendon transfers has its own set of merits and demerits. Selection of donor tendons as per occupational need of patients is utmost important. Patients in our series were satisfied with set of transfers using Pronator teres(PT) for wrist extension, Flexor carpi radialis (FCR) for finger extension and rerouted Palmaris longus (PL) for extension of thumb. Flexor carpi ulnaris (FCU) is important for power grip. Wrist stability may be compromised by using FCU which results in loss of power grip due to radial deviation and difficulty in manual labour. Holding large object may be more difficult when using FCU as it is the more powerful wrist flexor and using it results in greater decrease in wrist flexion strength compared to FCR. Although, these effects of using FCU may not be as apparent when using it in non – dominant extremity in patients performing mostly office work. Hence, we recommend that FCU must be sparingly used in patients with heavy occupational demands. Patients with FCR transfer were more satisfied as a greater percentage of our patients were manual workers who were able to perform sturdy occupational demands due to maintained power of wrist flexion and no issue of wrist stability being compromised as FCU was retained. Although small sample size is the limitation of this study.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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