Surgical treatment outcome of wrist flexion contracture in children with cerebral palsy through temporary extra-articular arthrodesis

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Cerebral palsy (CP) is the primary contributing cause of the clinical presentation of spastic hand [1, 2], which is characterized as a functional disorder of the upper limb due to spasticity of certain muscle groups that ultimately lead to the formation of, first, tonic and, then, fixed extremity joints contractures [3]. The orthopedic status of a spastic hand is most often represented by adduction contracture of the shoulder joint, flexion elbow joint contracture, pronation contracture of the forearm, flexion contracture of the wrist joint and fingers, and adduction contracture of the thumb [1, 3, 4]. Despite that all of these abovementioned contractures undoubtedly have negative influences on the motor capabilities of the upper limb, it is the vicious position of the hand that often emerges as a factor that severely limits the functions of the hand.

Surgical approaches to the treatment of flexion contracture of the wrist joint can be classified into 2 main groups: soft tissue interventions aimed at creating a balance between the flexor and extensor muscles of the hand by lengthening or transplanting the tendons and bone surgery aimed at stabilizing the wrist joint [1, 5].

The analysis of the relevant literature provides conflicting answers to the questions on the indications for the first-type of surgeries. Some past authors [5–7] do not consider the degree of contracture severity to be decisive; rather they consider it to be due to the lack of effect from conservative treatment. Meanwhile, some other authors are guided by the contracture severity. For example, Miller [1] provides a working classification of flexion contracture of the hand and considers the indications for the type of surgical treatment depending on the range of motion.

The indications for arthrodesis surgery on the wrist joint have been described in the literature, with almost all authors agreeing that these are severe flexion contractures in patients without the expected functional perspective of treatment [1, 8–10]. In such patients, this type of treatment is considered effective and that with a stable clinical outcome. However, the question of the admissibility of arthrodesis of the wrist joint for severe flexion contractures of the wrist joint in patients with the opportunity to achieve hand functioning after treatment remains unresolved. Moreover, an extremely controversial situation has developed with regard to the surgical treatment of moderate flexion deformity of the wrist joint. Interventions on the soft tissues described in the literature [1, 2, 5] are characterized by low efficiency and rapid recurrence of contractures, and the development of indications for arthrodesis surgeries in this category of patients remains unestablished.

Considering the heterogeneity of the groups involved, the lack of a unified classification system for the preoperative condition and the system for assessing the functional outcome, it is impossible to conduct a comparative analysis of the soft tissues with the arthrodesis methods of surgical treatment of moderate wrist deformities presented in the literature.

The present study aimed to compare the efficacy of a new approach for the surgical treatment of flexion contracture of the wrist joint in pediatric patients with CP, including temporary extra-articular arthrodesis and transplantation of the flexors of the hand to the extensors, according to the Green’s surgery guidelines.

Materials and methods

The present study was based on the analysis of the results of examining and treating 26 patients with CP at the H. Turner National Medical Research Center for Сhildren’s Orthopedics and Trauma Surgery. The patients were classified into 2 groups: The group 1 (archived; n = 13) included children who underwent treatment at our clinic during 2011–2018 [11]. These patients underwent transplantation of m. flexor carpi ulnaris tendon to m. extensor carpi radialis brevis/longus (the Green’s surgery). The group 2 (n = 13) included children who underwent examination and received treatment during 2018–2020. Temporary extra-articular arthrodesis of the wrist joint was accordingly performed to these patients.

The study protocol is illustrated in Figure 1.

 

Fig. 1. Study design

 

Criteria for inclusion in the study group were as follows:

• GMFCS level 1–4;
• The absence of functionally significant contractures in the upper limb joints (maximum 30° deficit of extension of the elbow joint, which provides the possibility of active supination of the forearm to the middle rotational position), except for the wrist joint;
• Deficiency of active dorsal flexion of the hand with the impossibility of actively bringing it to a neutral position;
• The possibility of passive bringing of the hand to a neutral position; in patients with more pronounced fixed contracture, preoperative preparation was performed, which involved staged plaster corrections [12];
• The absence of any surgical treatment on the upper limb in the history;
• Patients in whom the last course of botulinum therapy was performed not earlier than 6 months before the treatment started.

The absence of voluntary movements of the upper limb, as well as pronounced mental retardation or the lack of motivation to undergo postoperative rehabilitation, was considered as exclusion criteria for the study.

The subjects were distributed by gender so that group 1 included 8 men (62%) and 5 women (38%), while group 2 included 7 (54 %) men and 6 (46%) women.

The age of the patients varied from 6 to 17 years, with the average age being 9.92 ± 2.39 years in group 1 and 13.07 ± 3.12 years in group 2. Neurological diagnosis was hemiparesis in 73% of the study patients and spastic diplegia in the remaining patients. The motor abilities of levels 1–3 with reference to the GMFCS scale were registered in 85% of the patients and those of level 4 were registered in 4 patients (15%; 1 from group 1 and 3 from group 2). Despite that the group 2 patients were older than group 1 patients; the severity of flexion contracture in the wrist joint was practically the same in both the groups. All patients or their representatives provided voluntarily signed informed consent for their participation in the study.

The main criteria for the treatment efficiency were the indicators of clinical trials. The amplitude of active and passive movements in the wrist joint with fully extended fingers was assessed. The 0° position was considered to be the position of full flexion of the hand (at a right angle to the forearm); thus, the neutral position of the hand was 90°, with the maximum extension of 170°.

The functionality of the upper limb was determined using the international classification system MACS (Manual Ability Classification System for Children with Cerebral Palsy 4–18 years) of 2002 as well as the BBT, and the number of cubes that the patient could transfer from one box to another in 1 min was determined.

In order to assess the functional state of the forearm and hand muscles in the group 2 patients, the surface EMG and the stimulation electroneuromyography (ENMG) were employed. The study was performed on a four-channel electroneuromyograph by Neurosoft company (Russia). The main reason for including this method in the study was the desire to assess the reaction of the forearm and hand muscles to the long-term exclusion from movement of such a large joint of the upper limb as the wrist. An electrophysiological examination of all patients was conducted before the surgery as well as in the presence of temporary arthrodesis of the wrist joint (6 months and 1 year after the surgery).

When conducting surface EMG in the group 2 children using a cutaneous sensor, the bioelectrical activity of the forearm muscles (m. flexor carpi radialis, m. flexor carpi ulnaris, m. flexor digitorum superf., m. extensor сarpi radialis, m. extensor carpi ulnaris, m. extensor digitorum) was recorded.

The study was conducted at rest and in the mode of voluntary muscle activation on the upper limb from the surgical side and on the symmetrical side. To assess the disorders, the average EMG amplitude (μV) was considered; the ratio of activity on the affected and the healthy sides was calculated; and the degree of muscle activity decrease on the affected side (%) was determined.

During ENMG, the sensory and motor fibers of the median, ulnar, and radial nerves were examined with a current of 0.1-ms duration and an intensity of 18–50 mA as per the standard technique. The conduction velocity (m/s) along the sensory and motor fibers and the amplitude of sensory potentials and motor (muscle) responses (M-responses) were also assessed. When the median nerve was stimulated, the M-response with m. abd. poll. brev. was recorded, when the ulnar nerve was stimulated, that with m. abd. digitimin. was recorded, and when radial nerve was stimulated, that with m. ext. ind. pr. was recorded.

The surgical treatment of patients in group 1 was performed according to the modified Green’s technique [11] (Fig. 2).

 

Fig. 2. The surgical stages of transposition of m. flexor carpi ulnaris from the position of the flexor of the hand to the position of the extensor: a — mobilized tendon of m. flexor carpi ulnaris dissected from the insertion site; b — the insertion site on the dorsum of the forearm of the tendon of m. flexor carpi ulnaris to the tendons of m. extensor carpi radialis brevis and longus

 

From a linear incision along the flexor surface of the forearm in the projection of the wrist joint, after dissection of the subcutaneous fat and superficial fascia of the forearm, the m. flexor carpi ulnaris tendon was found. After mobilization of the tendon from the attachment point to the tendon transition to the muscular portion, it was dissected from the fixation point (pisiform bone). The tendons of m. extensor carpi radialis brevis and longus were isolated from a 3-cm long incision along the dorsum of the hand in the lower-third of the forearm. The hand was brought to the position of excessive dorsal extension (110°) and fixed in the position achieved with 2 Kirschner wires. The distal end of the tendon of m. flexor carpi ulnaris was brought to the forearm dorsum using the probe and then sutured with m. extensor carpi radialis brevis and longus with tension.

The immobilization period after the surgical treatment was 4 weeks. No complications were registered during this period.

Surgical intervention in the group 2 patients was performed as follows (Fig. 3): From a longitudinal incision along the ulnar surface of the forearm and hand from the center of the metacarpal bone V to the border of the lower-third and middle-third of the forearm, a plate with angular stability was placed on the bone, which was fixed with screws passed through the ulnar, radial, carpal bones, as well as the metadiaphyseal region of metacarpal bones V, ΙV, ΙΙΙ, and II. The hand was stabilized in the middle position or in the position of physiological extension at the wrist joint (100°). The forearm was fixed in the middle rotational position. The limb was immobilized with a short plaster cast or splint for 2–3 days until the pain syndrome elimination. No orthosis was used later.

 

Fig. 3. The surgical stages of temporary wrist joint arthrodesis: a — planned surgical approach; b — surgical metal structure installed for temporary arthrodesis; c—radiograph of the wrist joint in the frontal view with the installed metal structure

 

Statistical analysis was performed by using the SPSS v.17.0 software (IBM, USA) and visualization by using the Graphpad Prizma 8 software (v.8.3.4.) (GraphPad Software, USA). The methods of descriptive statistics were used, with the determination of the mean value and standard deviation. For quantitative data, the normality of distribution was assessed using the Kolmogorov–Smirnov test, the Shapiro–Wilk test, and Q-Qplots graphical visualization. To compare the quantitative data, the Friedman test was used for ≥3 dependent samples. The Wilcoxon test was used for 2 dependent samples and the Mann–Whitney U-test was used for 2 independent samples. The level of probability of type I error <5% (p < 0.05) was considered to be statistically significant.

Results

Data on the range of movements in the wrist joint before the surgery as well as that 6 months and 1 year after the surgical treatment are presented in Tables 1 and 2, respectively, and the data on the functional changes in the state of the upper limb are presented in Table 3. Intergroup analysis performed before the surgery showed no statistically significant differences in most of the parameters studied (p > 0.05), which prompted further research.

 

Table 1

Characteristics of the average parameters of passive extension in the wrist joint of pediatric patients with CP before the surgical treatment and at 6 months and 1 year after the surgery

Group	Passive extension in the wrist joint (n = 26)
	before surgery	after 6 months	after 1 year	the difference in average values (before surgery and after 6 months/ before surgery and after 1 year)
1	116.1 ± 19.7	130.7 ± 17.7	125.7 ± 18.9	14.6 (p = 0.003) / 9.6 (p = 0.001)
2	111.5 ± 17.3	–	108.8 ± 6.5	–2.7 (p = 0.858)
p-value	p = 0.511	–	p = 0.026	–

 

Table 2

Characteristics of the average parameters of active extension in the wrist joint in pediatric patients with CP before the surgical treatment and at 6 months and 1 year after the surgery

Group	Active extension in the wrist joint (n = 26)
	before surgery	after 6 months	after 1 year	the difference in average values (before surgery and after 6 months/ before surgery and after 1 year)
1	57.3 ± 11.6	92.6 ± 14.6	89.2 ± 12.5	35.3 (p = 0.001) / 31.9 (p = 0.001)
2	59.6 ± 16.8	–	105.3 ± 5.5	45.7 (p = 0.001)
p-value	p = 0.840	–	p < 0.001	–

 

No data describing passive and active extension in the wrist joint in the patients of the group 2 was recorded 6 months after the surgical treatment, since, at that moment, the wrist joint was arthrodesized. The average value characterizing the position in the wrist joint during temporary arthrodesis was determined to be 96.9° ± 1.8°.

When analyzing the indices of passive extension in the wrist joint, significant multidirectional dynamics was noted. In group 1 patients, extension increased by 9.6°, and, in group 2, it decreased by 2.7°.

The analysis of data presented in Table 2 suggest that the treatment provided an active extension index increment by 35.3° during the first 6 months in the group 1 patients. The dynamics of this indicator over the year was 31.9° in group 1 patients and 45.7° in group 2 patients.

In Table 3, we have not indicated the standard error in assessing the performance indicators on the MACS scale due to its insignificance.

 

Table 3

Characteristics of the functional indicators of the upper limb in pediatric patients with CP before the surgical treatment and at 6 months and 1 year after the surgery

Group	Manual Ability Classification System for Children with Cerebral Palsy, points			Block and Box test, number of cubes
	before surgery	after 6 months	after 1 year	before surgery	after 6 months	after 1 year
1	4.3	3.4	3.6	18.3 ± 4.4	24.3 ± 3.7	26.3 ± 4.9
2	4.6	3.3	3.4	13.7 ± 8.2	14.8 ± 6.9	15.3 ± 6.6
p-value	p = 0.264	p = 0.511	p = 0.418	p < 0.001	p < 0.001	p < 0.001

 

Figure 4 represents the graph of the changes in the results of the main study indicators between the patients of both the groups 1 and 2.

 

Fig. 4. The changes in the indicators of active and passive extensions in the wrist joint, functional assessment on the MACS scale and Block and Box test (BBT): a–d — in group 1; e–h — in group 2

 

The parents of patients in both the groups reported an improvement in the hand appearance after surgical treatment.

An EMG study of the forearm and hand muscles prior to surgical treatment in all of the study CP patients revealed a decrease in the amplitude of voluntary activation of the flexor and extensor muscles of the hand in the operated limb.

The voluntary activity of the hand extensor muscles was, on an average, reduced significantly by 63.4% in caomparison with that of the healthy hand, while that of the flexor muscles was reduced by 49.6%. On the other hand, the degree of electrogenesis decrease prevailed in m. extensor carpi radialis (64%) in comparison to m. extensor. digitorum (47%) and m. extensor carpi ulnaris (34%).

Based on the ENMG study on sensory and motor fibers of the median, ulnar, and radial nerves, no signs of conduction disturbance were found.

The amplitudes of sensory potentials from the upper extremities in all cases were within the age norm. Examination of the motor fibers of the upper limbs on the affected side revealed that all children had a decrease in the amplitudes of M-responses of mild severity (on an average, 28% had below the norm values).

EMG examination after the surgical treatment for group 2 revealed that 6 months after arthrodesis of the wrist joint, the voluntary activity of m. extensor et flexor carpi radialis decreased by 80%–90% or was absent. After the removal of the metal structure and on completing the course of rehabilitation, the voluntary activity of the hand extensor muscles increased significantly when compared with that before the surgery, by 17% for m. extensor carpi radiali and by 27% for m. extensor digitorum. Meanwhile, the voluntary activity of the hand flexor muscles decreased on an average by 10.4%. A change was noted in the voluntary activity of the hand muscles in the form of an increase in the activity of m. adductor pollicis (by 26%) and in that of m. abductor pollicis brevis (by 17%).

Discussion

The present data indicate statistically significant differences in the indicators of active and passive extension in the wrist joint and the assessment of hand function using the BBT before and after treatment in both the groups, which helps conclude regarding efficiency of these types of surgical intervention.

The indicator of the dynamics of the upper limb functionality as a result of surgical treatment according to the MACS system (p = 0.511) during the follow-up period of 6 months and those of passive extension in the wrist joint in group 2 patients (p = 0.858) were statistically insignificant.

Considering the significant positive dynamics of active extension in the wrist joint in group 2 patients after the removal of metal structures, the absence of ankylosing of the wrist joint after 1 year of immobilization can be stated.

No significant change in the amplitude of passive extension in the wrist joint was expected in our study because all patients had undergone preoperative preparation that enabled elimination of most of the contracture before the surgery. Despite this issue, in the group 1 patients, the passive movement amplitude increased (+9.7°) in excess of that achieved by preoperative preparation. This phenomenon can be explained by the extensor effect of the transplanted tendon and the active rehabilitation during the postoperative period.

Table 2 is more significant with respect to the clinical assessment of surgical treatment, as it demonstrates the dynamics of active movements. This table did not include the outcomes of hand extension in group 2 patients during the 6-month period, since, then, they showed no movement in the wrist joint. In patients of both the groups, active movements increased significantly (31.9° in group 1 and 45.7° in group 2) after 1 year of surgical treatment and after completing the course of rehabilitation. Moreover, the technique of temporary arthrodesis showed statistically significant effectiveness in relation to this parameter, which indicates the need for a longer period of observation before arriving at a definitive conclusion. In group 1, statistically significant negative dynamics of the average indicator of active hand extension within the period of 6 months to 1 year (from 35.3° to 31.9°) was noted. A similar trend could not be excluded in group 2 patients during the 6-month period after the removal of the metal structures. We thus assume that the gradual recurrence of contracture in the group 1 patients was noted only in children with initially more pronounced fixed contracture and, accordingly, a large number of preoperative plaster corrections were made. Among the group 1 patients, who did not need preoperative preparation, no relapse occurred during the follow-up period. In the group 2 patients, no relationship was recorded between the active range of motion in the wrist joint after the removal of the metal structure and the initial severity of contracture. Thus, it can be assumed that the impossibility of passive correction of the hand to an anatomically neutral position can serve as a criterion for selecting between the proposed methods of surgical treatment. However, further research is warranted to confirm this assumption.

The MACS indicators of the upper limb functionality, which indicated the general condition of the hand, were almost identical in both the groups. However, the BBT was more suitable for assessing the hand function. For instance, in group 1 patients, the average dynamics with reference to the BBT as a result of treatment amounted to 8 additional cubes, while it was only 1.6 in group 2 patients. Such indicators thus confirm that full extension in the wrist joint is not essential for the limb function. To improve the hand function, it is sufficient to extend it actively. A similar opinion is shared by the literature [1, 2, 10]. It is thus believed that arthrodesis of the wrist joint negatively affects the function of the hand, since the movement in the wrist joint is used by patients to facilitate flexion and extension of the fingers. According to Miller [1], although the children were satisfied with the treatment outcome in cosmetic terms, several of them lost even the minor functional capabilities of the hand that they had before the surgery. However, an opposite opinion is shared by Rayan [13], who performed arthrodesis of the wrist joint in 11 patients with a spastic hand aged 12–30 years and noted an obvious positive dynamics of hand functions in most patients from the treatment. In addition, Alexander [14] performed 19 carpal arthrodesis in 18 CP patients of average age 15.8 years. His study had an extremely long follow-up period of up to 4.5 years. In the assessment on the House scale, 83% of the patients reported an improvement in their hand functional capabilities after arthrodesis. Moreover, Neuhaus [15] considers arthrodesis of the wrist joint as a stable and effective surgery for eliminating the deformity of the wrist joint of any severity. According to his study, the upper limb functionality improvement with such a surgery averages +2 points on the House scale.

In this study, EMG revealed a decrease in the voluntary activity of the forearm and hand muscles in all patients with a spastic hand. Flexion contracture of the wrist joint led to a decrease in the functional voluntary activity of the extensors of the fingers and the hand, but the M-response suggested that the triggered muscle activity was normal or only slightly decreased.his observation indicates the significant functional reserve of the forearm and hand muscles as well as their ability to activate when the contracture is eliminated. We could confirm this with an EMG examination after the surgery. After arthrodesis of the wrist and hand joints in all CP patients, the voluntary contractility of the extensor muscles of the fingers and hand increased, and the functional activity of m. adductor pollicis and m. abductor pollicis brevis also improved.

The reasons for the increase in the voluntary activity of the extensor muscles of the hand in comparison with those of muscle electrogenesis before the surgery in group 2 patients remains unclear. This phenomenon needs to be studied further. We thus assume that, in the presence of arthrodesis of the wrist joint, improvement in muscle electrogenesis can be attributed to the elimination of overstretching of the extensor muscles as a result of their gradual retraction.

Thus, Green’s surgery is less effective than temporary arthrodesis as an approach for correcting flexion contracture of the wrist joint. However, the functional performance of the Green’s surgery is better. Depending on the purpose of the surgical treatment, a method of contracture correction can be selected. The Green’s surgery is selected with a high-functional perspective; and, in case it becomes necessary to correct severe contracture with doubtful functional prospects, temporary arthrodesis can be selected. We thus believe that, in doubtful cases, temporary arthrodesis is more promising, as it combines the advantages of both the approaches, namely the stability of arthrodesis with the installed metal structure and the possibility of active movements in the wrist joint so as to maximize the hand function after the removal of the structure. In addition, if the functional prospects of the upper limb are assessed more positively after the metal structure removal, this approach can subsequently enable performance of the Green’s surgery.

Study limitation

The present study is preliminary and incomplete. Considering the novelty of the temporary arthrodesis technique and the small number of patients with indications for this type of treatment included in this study, we did not have the opportunity to create homogeneous groups based on age, gender, GMFS level, MACS, and the functional test results. Due to the preoperative preparation, we could achieve uniformity of the groups in terms of angulometry (active and passive extension in the wrist joint). Since the technique under study is new and the primary clinical results were assessed to be good, we plan to expand this study and create groups of patients who are homogeneous in terms of age and functional parameters. This step will increase the study significance as well as facilitate development of an unambiguous opinion about the competitive advantages of the available methods of surgical correction of the wrist joint flexion contracture. In addition, in future studies, we propose to use the classification system based on the communication disorders system (CFCS), since the patient’s motivation and ability to conduct active postoperative rehabilitation seems crucial in achieving functional outcomes after intervention on the upper limb.

Conclusion

Transplantation of m. flexor carpi ulnaris tendon to m. extensor carpi radialis brevis/longus (Green surgery) is a well-established method for treating wrist flexion contracture in patients with active extension deficit, but it has no significance in fixed flexion contracture. In our study, good clinical outcomes were obtained through this surgery for the treatment of such patients. The proposed new method of extra-articular arthrodesis of the hand joints will enable correction of the contracture more efficiently, albeit with a lower functional effect. This type of surgical treatment prevents occurrence of trauma to the tendon apparatus, due to which active restorative treatment can be performed immediately after the surgery, and the patient does not require postoperative orthotics.

Further study of the results of treatment in group 2 patients is necessary to assess their stability.

Additional information

Source of funding. State budget financing. The work was performed within the framework of the state assignment of the Ministry of Health of the Russian Federation, R&D No. АААА-А18-118122690160-5.

Conflict of interests. The authors declare no conflict of interests.

Ethical statement. The protocol for the examination and treatment of pediatric patients was approved by the local ethical committee of the H. Turner National Medical Research Center for Сhildren’s Orthopedics and Trauma Surgery (protocol No. 20-1 of 04/27/2020).

The patients (their representatives) gave their consent to treatment, processing, and publication of personal data and photographic materials.

Author contributions

V.A. Novikov developed the study design, wrote all sections of the article, collected and analyzed the data, reviewed the literature, and performed surgical treatment of patients and their postoperative management.

V.V. Umnov performed surgical treatment of patients, developed the study methodology, formulated the aims, and performed staged and final editing of the text of the article.

D.V. Umnov collected and analyzed the clinical materials.

All authors made significant contributions to the research and preparation of the article and read and approved the final version of the manuscript before submission for publication.

About the authors

Vladimir A. Novikov

H. Turner National Medical Research Center for Сhildren’s Orthopedics and Trauma Surgery

Author for correspondence.
Email: novikov.turner@gmail.com
ORCID iD: 0000-0002-3754-4090

MD, PhD, Research Associate of the Department of Infantile Cerebral Palsy

Russian Federation, Saint Petersburg

Valery V. Umnov

H. Turner National Medical Research Center for Сhildren’s Orthopedics and Trauma Surgery

Email: umnovvv@gmail.com
ORCID iD: 0000-0002-5721-8575

MD, PhD, D.Sc., leading researcher of the Department of Infantile Cerebral Palsy

Russian Federation, Saint Petersburg

Dmitry V. Umnov

H. Turner National Medical Research Center for Сhildren’s Orthopedics and Trauma Surgery

Email: dmitry.umnov@gmail.com
ORCID iD: 0000-0003-4293-1607

MD, PhD, Research Associate of the Department of Infantile Cerebral Palsy

Russian Federation, Saint Petersburg

References

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