IMMEDIATE POST-OPERATIVE ACTIVE MOBILIZATION FOLLOWING OPPONENSPLASTY

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1 The Indian Journal of Occupational Therapy : Vol. XL : No. 3 () IMMEDIATE POST-OPERATIVE ACTIVE MOBILIZATION FOLLOWING OPPONENSPLASTY *Dibya Jyoti Sahoo, M.O.Th.; Co-author : **P. Nageswar Patra, B.P.T., *** Santosh Rath, M.S. Abstract : Objective: The purpose of this study is to compare the results of Immediate Post-operative Active Mobilization (IPAM) for opponensplasty with post-operative immobilization. Methodology: In a prospective study, 5 cases of pure lower median nerve and 10 cases of ulnar-median nerve paralysis had opposition tendon transfer with FDSR followed by IPAM from 48 hours after surgery. Primary outcomes are active abduction, pinch pattern, pinch strength. The results of IPAM were compared with a retrospective cohort of similar transfer operated prior to the IPAM trial and immobilized in a cast for 3 weeks. Statistical analysis was done by student t test. Results: There were no incidences of tendon pullout during IPAM for opponensplasty. There were no differences in outcome between the 2 groups at late follow-up evaluations, with all opposition transfers achieving good results. Conclusion: The concept of applying IPAM for opponens tendon transfer is feasible, safe and without much discomfort to the patient. Application of this technique with proper precaution reduces morbidity period by 19 days and enables earlier return of function. Keywords : Immediate Post-operative Active Mobilization, Opponens Tendon Transfer, Post-operative Rehabilitation. INTRODUCTION Opposition of the thumb is the most important component of normal hand function. It is a complex movement requiring trapezio-metacarpal joint abduction, flexion and pronation 4. Thumb opposition requires the action of several muscles. Long et al (1970) have grouped the muscular actions affecting the thumb while pinching into two components: those responsible for positioning the thumb and those providing compressive forces for pinch 7. The positioning of the thumb towards opposition is primarily a function of median nerve, but the power of the pinch is a function of the ulnar nerve 11. Abductor pollicis brevis and the opponens carry out the abduction component along with the flexor pollicis brevis superficial head. Abductor pollicis longus effects retroposition of the metacarpal and has little role in thumb opposition. The flexion component is carried out by the flexors pollicis brevis * Occupational Therapist ** Physiotherapist *** Hand Surgeon Place of Study : Paralytic Limb Research Foundation, Bhubaneswar, Orissa, India Period of Study : Oct Dec Correspondence : Dr. Dibya Jyoti Sahoo Plot No. 221, Shastri Nagar, Unit IV, Bidyut Marg, Bhubaneswar Orissa, India Tel. : dibyajyoti.8@gmail.com Paper was presented in 45th Annual National Conference of AIOTA : EMCON'08 in Jan at Nagpur. (FPB) and longus (FPL). Simultaneously the lumbrical, interossei and long flexors of the index and middle fingers are activated along with the adductor pollicis to complete the pinch. An opposable thumb is responsible for most of the pulp-to-pulp pinch and grasping movements involved in dayto-day activities like writing, buttoning a jacket, tying shoelaces, picking up a coin, and other BADL. Therefore, its loss constitutes a significant disability. The loss of this movement may occur as a result of median or ulnar-median nerve paralysis as seen in peripheral nerve injuries, peripheral neuropathies and poliomyelitis. Leprosy is the most common cause of ulnar and median palsied thumb in countries where it is endemic 7. In median nerve palsies, only the central forces i.e., abductor pollicis brevis (APB) and opponens pollicis (OP) are deficient resulting in ape thumb deformity. Therefore these cases require only opponens transfer. However, in combined palsies, ulnar forces (flexor pollicis brevis [FPB] and adductor pollicis) and central forces are both deficient resulting in combination of ape thumb and intrinsic minus or Z-thumb deformity 7. Therefore, in these cases the aim of surgery is to restore abduction and opposition of the thumb and stabilize the thumb joints so that an effective precision handling with a tripod pinch of adequate strength can be performed. Therefore, in case of combined palsy, first Z- thumb is corrected followed by ape thumb correction. Immobilization of the part after tendon transfer surgery is the standard protocol in clinical practice 18. In case of opponens transfer, the hands were immobilized for a period of 3 weeks, followed by further 4 weeks of post-operative IJOT : Vol. XL : No. 3 65

2 reeducation. This prolonged period of morbidity results in lost workdays for patients and increases the medical costs. Studies done by Small, Brennen and Colville 16, Silfverskiold and May 14 and Sirotakova and Elliot 15 reported improved outcomes after early controlled active mobilization for flexor tendon repairs. In one study done by Germann et al 5, in which they have compared the results of early dynamic motion and post-operative immobilization after EIP transfer to restore active thumb extension, found improved outcomes and faster recovery of hand function in the early dynamic group. In another study done by Rath 12 reported that early mobilization after opponens transfer in isolated median nerve palsy have similar outcomes as that of standard protocol for immobilization. In our study, the hypothesis is that the IPAM protocol after opponens transfer in case of pure median and ulnar-median palsy would achieve similar outcomes to those of standard practice of immobilization provided the tendon insertion is protected during mobilization. A prospective trial of IPAM after opposition transfer in thumbs with isolated median nerve and ulnar-median nerve palsy was designed and the results were compared with a retrospective cohort of similar transfer operated prior to the IPAM trial and immobilized in a cast for 3 weeks. Subjects: METHODOLOGY In a prospective trial 15 consecutive thumbs due to paralysis of isolated median nerve or ulnar-median nerve in Hansen s disease were included in the study. There were 5 thumbs with isolated median nerve & 10 thumbs with ulnar-median palsy of > 1 year duration. Historical records of 15 thumbs with identical paralysis (5 pure median and 10 ulnar-median palsy) with opposition tendon transfer done prior to the prospective trial at the same institution with post-operative immobilization of the hand for three weeks and with followup more than 1 year formed the comparison group (Immobilization group). The selection criteria were similar to both groups with patients being referred from the same geographical area and patient population for deformity correction. Inclusion criteria includes 1) irreversible isolated median or ulnar-median nerve paralysis of > 1 year duration, 2) completed multi drug therapy for treatment of Hansen s disease, 3) mobile thumbs with no contracture angles of MCP joint / IP joint at the time of surgery, 4) passive ABD > Exclusion criteria includes 1) stiff hand, 2) callosities and absorption of digits. In the IPAM group there were twelve males (one had bilateral thumb correction) and two females in the age bands of 14 years to 40 years. The mean duration of paralysis was 4.6 years (range, 1.6 to 12; SD 3.3 years). Each individual in IPAM group was explained the proposed change in post-operative protocol and informed consent obtained. The likelihood of discomfort during early postoperative active mobilization and possible complications of tendon pullout requiring re-exploration or revision surgery were discussed along with the potential benefits of earlier rehabilitation. Institutional review committee approval was obtained for the trial. Assessment: Pre-operative evaluation included a detailed general assessment, motor examination using the Medical Research Council grading, and sensory testing with 5/O nylon filaments. It is followed by evaluation of pinch strength, pinch pattern, and thumb active range of abduction (ARA). Pinch strength was measured with a handheld pinch gauge (North Coast Medical INC., Morgan Hill, CA). The average of three consecutive measurements was used to calculate the pinch or grip strength. Pinch pattern: It is assessed by observation as pulp-to-pulp or tip-to-tip. Thumb active range of abduction: The difference between active abduction angle (AAA) and resting abduction angle (RAA) is the ARA. A thumb web angle of 45 or more is essential so that the thumb was free to circumduct. Pre-operative Therapy 11,14,18 : The patient is taught isolation exercise to contract the ring finger FDS (FDSR) on instruction and simultaneously relax the other three fingers FDS. Strengthening of FDSR is done by resisted exercises by applying resistance on the middle phalanx of ring finger during PIP flexion. It is followed by stretching of 1 st web space if any contracture is present. Before stretching is started, molten wax kept at as temperature of 45 0 C to 50 0 C is poured on the hand which is then covered by a linen cloth. The wax is removed after minutes. Wax bath help to loosen and relax soft tissue contractures. After every session, an opponens splint is given to the patient to be worn for about hours a day. This is continued for 1-2 weeks. Surgical procedure 13,18 : In case of pure median nerve palsy, a standard opposition transfer procedure was performed using the FDS of ring finger (FDSR). The route of transfer and pulley was around the pisiform. The tension was adjusted to 10 0 less than the maximum passive abduction of the thumb. The transferred tendon was sutured to the tendon of the APB and then to the ulnar capsule of the MCP joint with commercially available size 1 monofilament nylon suture with a tensile strength of 4kg. The resting abduction angle of the thumb was measured at the end of the procedure. In case of immobilization group, the patients had plaster-of-paris casts applied with the thumb IJOT : Vol. XL : No. 3 66

3 Figure-1 Tuck-in splint in full abduction. But in case of IPAM group, a Tuck-in Splint (Figure 1) was molded in the first web space to keep the thumb in full abduction/rotation and a dorsal splint was applied to the wrist in neutral position for pain relief. But in case of ulnar-median nerve palsy, a first MCP joint stabilization procedure along with claw correction was done. After one month of discharge opponens tendon transfer was done in the same procedure as described above. Post-operative Rehabilitation Protocol: The post-operative rehabilitation protocol 13,18 was identical for both the groups except that in IPAM group, the transfer was mobilized actively 48 hours after surgery and in immobilization group, the transfer was mobilized at the beginning of fourth week after surgery. IPAM group patients had therapy twice a day for the first two weeks and thereafter once a day, similar to immobilization group patients. The rehabilitation procedures in the first, second, third, and fourth postoperative weeks in IPAM group correspond to those fourth, fifth, sixth, and seventh postoperative weeks in immobilization group. First week: Isolation exercises. The plaster slab is removed followed by measurement of RAA daily to detect any loss of tension of the tendon transfer. Ten repetitions of isolated contractions of the transferred tendon were started, eliminating gravity, with the wrist in neutral and then in 30 0 of flexion. The patient will feel the contraction of the tendon and muscle. He will notice that, when he tries to flex PIP joint of ring finger, his thumb lifts up and rotates, i.e., abducts and opposes. At this stage, the patient must not extend the thumb, or use the EPL. Then ten repetitions of 10 0 CMC movements are also started. The sessions were kept short to 10 repetitions twice a day to avoid fatigue and overstraining of the transferred muscle. After therapy, the tuck-in splint and the dorsal plaster slab is reapplied. The active abduction angle (AAA) was recorded at the end of each week. Second week: Integration exercises. The thumb is incorporated in the function of pinch with opposing digits. Active abduction-opposition of 1 st CMC joint against gravity is started with wrist in neutral followed by wrist in 30 o flexion. The patient is asked to attempt thumbring finger pulp-to-pulp pinch. This facilitates isolated functioning of the transfer. It is followed by thumb-middle finger and thumb-index finger pulp-to-pulp pinch. Towards the end of second week, thumb-index-middle finger pulp-topulp pinch as tripod pinch is attempted. The RAA was in the range of and this facilitated tripod pinch by the index and middle finger without need for wider abduction of thumb. Patients with earlier pain relief and quicker integration progressed to activities such as picking up small light objects weighing less than 100grams. AAA and RAA are also recorded. After therapy, the dorsal plaster slab is reapplied. At the end of 15 th day sutures are removed. Third week: Strengthening and coordination exercises. Coordination activities, i.e., activities requiring grip and pulpto-pulp pinch in different wrist and forearm positions are started. In hand manipulation activities are introduced. It is followed by strengthening the transferred tendon. Gradually ADL requiring limited abduction are started (the maximum weight that is allowed to hold is grams). It is important to check any tendency of the thumb towards IP flexion during the pinch-grasp. Thumb adduction was avoided until the end of 3 rd week and a first web splint is given. After therapy, the dorsal plaster slab is reapplied. Fourth week: Thumb adduction was allowed and day time splinting is discontinued. In hand manipulation activities are continued. As ARA increases, BADL (i.e., self care activities) are started (the maximum weight that is allowed to hold is grams). Only night-time splinting is continued. In any case, the ARA did not increase along with reduction of RAA, thumb adduction was restricted and daytime splinting is IJOT : Vol. XL : No. 3 67

4 continued. Patients were discharged from the hospital as soon as the patient fulfills the discharge criteria - good integration of transfer (CMC joint abduction and opposition to all the fingers in wrist flexion, wrist neutral, and wrist extension), well healed wound, ability to perform his/her BADL confidently, strength of transfer of MRC grade 4 5. They were encouraged for return to work with strict instructions to avoid using the surgically treated hand to lift weights not more than 500 grams and to continue night splinting for 3 months. Unrestricted use of the surgically treated hand was allowed after the early assessment shows good pinch strength. The patient is called for follow-up assessments after discharge from the hospital after one month, two months, three months, six months, nine months, and twelve months. Evaluation of Results: The evaluations of results were based on the following outcomes measures: 1. Tendon transfer pullout or rupture during active mobilization in IPAM group. For the first three weeks, RAA was recorded daily before and after exercises to detect any sudden loss of tension during therapy. A sudden or progressive decrease in the RAA and ARA of the thumb would indicate pullout or rupture. 2. Evaluations of the results of opposition transfer in IPAM group and B. These were based on three relevant outcome parameters: the thumb ARA, pinch pattern, and pinch strength. These outcome measures were described by Rath (2006) for evaluating opposition transfer to the thumb for median and Table-1 Evaluation System Assessing Results of Opponens Transfer combined median-ulnar nerve paralysis. (Table 1). On an evaluation scale of 10, results were classified as good for scores of 8 to 10, fair for scores of 5 to 7, and poor for scores of less than equal to 4. Thumb active range of abduction. It indicates the ability of the transfer to position the thumb so that wider objects can be grasped. Pinch pattern. Opposition tendon transfer that restores adequate abduction and opposition will enable pulp-topulp pinch and those with limitation will achieve only pulpto-side or key pinch. Pinch strength. Pinch strength was measured with handheld pinch gauze (North Coastal Medical Inc., Morgan hills, CA). It indicates the strength restored to the thumb by opponens tendon transfer. In unilateral cases, it is better to compare with the unaffected hand and express the results as percentage of Normal. For bilateral cases a comparison with standard values has to be made. Comparison of Results of Opponens Transfer in IPAM and Immobilization group: The evaluation scores achieved by opposition transfer in IPAM group and immobilization group at early and late follow up were compared by student t test to determine the outcome of immediate active mobilization versus immobilization. RESULTS Tendon Transfer Pullout or Rupture during Active Mobilization: There was no pullout or rupture of the FDSR opposition tendon transfer during immediate active mobilization. Active Range of Abduction: In IPAM group, pre-operatively all hands were having active abduction ranging from When both the groups were compared, it was found to have statistically significant difference at discharge but not during the latest follow-up (Table 2). Pinch Pattern: All the hands in both the groups had tripod pinch at discharge and late follow-up (at more than equal to 1 year). Pinch Power: In IPAM group seven patients had good pinch strength, seven had fair strength and one had poor strength at discharge, but at the late follow-up, all the patients had good pinch strength. Comparison of Results: At discharge, 14 out of 15 opposition tendon transfers in both the groups had good results and one had fair result. At the late follow-up, all the opposition tendon transfers in both the groups had good results. The average evaluation score at discharge was 9 for both the groups and IJOT : Vol. XL : No. 3 68

5 Table-2 Comparison of Active Range of Abduction * Statistically significant difference at P 0.05 Table-3 Comparison of Scores P 0.05 at late follow-up it was 10 for both the groups (Table 3). The differences in the outcomes of opposition tendon transfer with IPAM and opposition tendon transfer with immobilization for three weeks was not found to be statistically significant. DISCUSSION FDSR transfer is considered as the standard procedure for restoration of thumb opposition after median or ulnar-median nerve paralysis. Post-operative treatment usually consists of immobilization of the hand in a plaster cast for 3 weeks, followed by muscle reeducation for 4 weeks 7,8-11,14. According to Brandsma and Ebenezer 2, the strength gained through preoperative therapy can be essentially lost after 3-4 weeks of immobilization. A study done by de Jong et al 4, showed prolonged period of functional flexor immobilization induces temporary loss of efficient control of hand movements characterized by increased cortical demand and reduced striatal involvement. A recent prospective randomized trial 5 of early dynamic motion with an extension out-trigger splint versus immobilization after EIP transfer to restore thumb extension showed a better achievement of outcomes of hand functions without compromising the end results. Patients with early dynamic motion recovered hand functions earlier as compared to immobilization, thereby making the procedure cost-effective. So immobilization is not absolutely necessary after tendon transfer. Taking all these things into consideration, we hypothesize that immediate active postoperative mobilization after opposition transfer would achieve similar outcomes to those of standard immobilization protocols, provided the strength of tendon insertion is increased and the tendon attachment is protected during mobilization. The result of this study supports the hypothesis and the postoperative therapy protocol produced benefits related to the reduced time of postoperative rehabilitation IJOT : Vol. XL : No. 3 69

6 and early return to work. IPAM protocol saved an average of 19 days, i.e., 40% reduction in postoperative rehabilitation time. In a regional context, where most people work in an informal sector with no illness or injury benefits, this considerably reduces the economic impact of reconstructive surgery and subsequent rehabilitation on the patients livelihood. Though active mobilization protocols after primary tendon repairs have improved outcomes without increasing tendon rupture, but early active mobilization after opponens tendon transfer does not alter the end outcomes compared with immobilization. The apparent benefits are reduced pain, early achievement of integration, reduced rehabilitation time and reduced cost to the individual. The potential risk of early mobilization however is a tendon pullout, which may require re-exploration or revision with a new donor. The patient has to understand this dilemma and be willing to accept the risks, although no such complications were observed in this trial. Regular postoperative follow-up is necessary in the first 3-6 months as the patient returns to full normal activities and has the greatest risk of stretching the transfer. Quicker return of ARA in the IPAM group is attributable to reduced adhesion formation due to active gliding of the transferred tendon, and this allows early return of function. The reduced morbidity and earlier return to work should improve the acceptance of tendon transfer for deformity correction irrespective of the cause of paralysis. Randomized controlled trials in future can investigate the changes with early mobilization versus immobilization in the early postoperative period. Additional studies are required to understand the patient s perspective and to quantify further the economic benefits of IPAM. These planned areas of work will help to define indications, techniques, and application of immediate active postoperative mobilization to various types of tendon transfer. CONCLUSION The concept of applying immediate active postoperative mobilization for opponens tendon transfer is feasible, safe and without much discomfort to the patient. Application of this technique with proper precaution reduces morbidity period by 19 days and enables earlier return of function. ACKNOWLEDGEMENT The authors would like to acknowledge all the patients for their participation in the study. REFERENCES 1. Anderson GA, Lee V, and Sundararaj GD.Opponensplasty By Extensor Indicis And Flexor Digitorum Superficialis Tendon Transfer. J Hand Surg 1992; 17B : Brandsma W, Ebenezer M. Pre- and Postoperative Therapy following Tendon Transfer Surgery. In: Surgical Reconstruction and Rehabilitation in Leprosy and Other Neuropathies. Kathmandu (Nepal): Ekta Books, 2004: Bunnell S. Opposition of the Thumb. 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