Post Operative Physiotherapy for Pronator Teres Tendon Transfer

Original Editor - Tanvi Korba 

Top Contributors - Tanvi Korba, Misha Ahir, Khloud Shreif, Kim Jackson, Carina Therese Magtibay, Vidya Acharya and Mohamed A Hassanin  

Introduction

Most common indication for upper extremity tendon transfer procedure is Peripheral nerve injuries that has no potential of improvement. Other common indications include loss of muscle or tendon following trauma, central neurologic deficits such as spinal cord injuries and cerebral palsy, and tendon ruptures in patients with rheumatoid arthritis. Other rarer disorders, including poliomyelitis and leprosy, can result in disability that may benefit from a tendon transfer procedure.

Patients with peripheral nerve injuries can benefit from the use of nerve injury rehabilitation techniques in their care, when recovery is poor tendon transfers is option with good functional recovery. Damage to peripheral nerves can impair an individual's ability to perform manual, social, and functional tasks.

Proximal radial nerve is most frequently injured in patients with humeral shaft fractures.It presents a challenging clinical scenario as patient has significant reduction in grip strength due to loss of wrist and finger extension thus, difficulty performing daily activities . Tendon or nerve transfers surgery are utilised if the functional recovery is not observed after primary nerve repair. This surgical option is available for reconstruction of the wrist, thumb, and finger extension.

Play Video

Local File

Procedure

The main goals while treating radial nerve palsy is to restore finger extension, thumb extension and wrist extension if higher radial nerve palsy. Several options for tendon transfers are available. However standard transfer called as Jones transfer is considered best:

• Pronator Teres to Extensor Carpi Radialis Brevis for restoration of wrist extension.
• Palmaris longus to Extensor Policis Longus for restoration of thumb extension.
• Flexor carpi Ulnaris to Extensor Digitorum communis(EDC) for restoration of finger extension.

other options: Flexor Digitorum Superficialis (Ring Finger)to Extensor digitorum communis or Flexor Carpi Ulnaris to EDC

Why these tendons:

The motor branch of the Flexor digitorum superficialis (FDS) was used for the motor branch of the Extensor carpi radialis Brevis (ECRB). It is mainly used for a synergistic effect. The FDS function gets affected if the only branch of the FDS nerve is cut off. In such case scenarios, pronator teres (PT) transfer to the Extensor carpi radialis longus (ECRL) nerve is preferred to achieve and restore wrist extension. For wrist extension reconstruction, the ECRB muscle is preferred over the ECRL due to ECRB muscle’s central location. That provides better-balanced radio-ulnar deviation during wrist extension. Outcomes of tendon transfer are considered favourable when patients achieve good wrist extension, finger extension, thumb extension, and hand grip.

This video describes the indications and techniques of tendon transfers for radial nerve palsy.

Indications of Surgery

Indications for tendon transfers in high radial nerve injuries are:

• Unlikely nerve recovery- No change or plateaued recovery observed over the past few months with non surgical management
• No recovery following primary nerve repair surgery
• Other indications: weakness for loss of function due to spinal cord injury, cerebral palsy, Brachial plexus injury.

Evaluation

A team approach can effectively address pre-operative issues and enhance post-operative success. The ideal team would consist of a hand surgeon, physician assistant or nurse practitioner, hand therapist ( Physical therapist or Occupational therapist), electro-diagnostician, social worker, the client, and family.

• Neural recovery status- By using electrodiagnostic tests such as electromyography or nerve conduction studies
• Motor assessment- Active and Passive range of motion available in the involved joint, active range during functional tasks
• Strength of the muscles- Manual muscle testing or hand-held dynamometry, Grip, and pinch dynamometers
• Assessment of function/ dexterity to document pre-operative performance
• Sensory Assessment- The Weinstein Enhanced Sensibility Test or Semmes-Weinstein monofilaments are used to measure touch pressure threshold and discrimination assessment using static or moving two-point discrimination.
• Patient-related factors such as compliance, motivation, finances, previous and current interests/ abilities including other psychosocial issues such as emotional distress due to neuropathic pain.
• Outcome measures- DASH score, Quick DASH score

Pre-Operative Physiotherapy

Pre- operative physiotherapy aims are to maintain full Range of Motion, educate patient about new muscle relationship, strengthening of donor tendons, protect de-sensate area.

Physiotherapy Interventions includes :-

1. Passive complete Joint Range of Motion Exercises.
2. Strengthening of Flexor musculature ( donor tendons) of wrist and fingers.
3. Skin care with special attention to de-sensate area.

Post-Operative Treatment

Education

This includes information on post-operative guidelines, activity limitations, importance of exercise programme, splints/ orthosis, and timeline for therapy. Physiotherapy regime is considered in 3 phases

Phase1: Protection Phase

Goal: Complete protection of transferred tendons, Prevent oedema

This entails guarding the area with reduced sensitivity and securing the surgical site. Following tendon transfer surgery, the affected limb is immobilised in a bulky dressing with a plaster cast. The extremity positioned in the orthosis depends on the surgical procedure and most preferred is wrist in about 15 to 30 extension, fingers and thumb in functional position. To prevent the operating limb from swelling, it is advised to keep it elevated. Non-involved proximal joint movement i.e shoulder and elbow helps to prevent secondary joint stiffness and decrease distal extremity oedema.

Phase 2:Phase of Transfer Activation

Goal: Prevent oedema, Scar Remodelling, Promotion of tendon excursion

Afterwards, around 3 weeks a customised thermoplastic orthosis replaces cast. The splint is assessed at regular intervals to ensure comfort and protection of the surgical site. This phase involves the transferred muscle's activation. Its started around 4 weeks or as surgeon advice. The transferred muscle's previous and current roles must be performed simultaneously in order for them to learn the new role.

In order to activate the pronator teres muscle, which is used as a wrist extensor during surgery, the patient must simultaneously pronate their forearm and extend their wrist. Patient is encouraged to perform extension of wrist with pronation of forearm. If patient has difficulty, combined wrist extension with forearm pronation can be first taught in non injured hand or the therapist uses the place-and-hold method for activation. In order to do this, the therapist must gently place the limb in the new position while asking the patient to hold it. Any jerky or forceful movements ought to be avoided. The forearm should be in a roughly 20-degree pronation; if the patient is experiencing difficulty activating the transfer, they are asked to perform pronation while receiving counter-pressure from the therapist. With the assistance of this resisted pronation, the transferred muscle will be stimulated to produce a wrist extension.

The flexor carpi Ulnaris is transferred to the extensor digitorum communis (EDC) to improve digit extension. The patient will be instructed to extend the MCP joints while flexing the wrist to neutral from an extended position during this phase. Patient is educated not to flex the wrist forcefully during this exercise. Any jerky or forceful movements ought to be avoided.

Palmaris Longus is transferred to Extensor Polices Longus to improve thumb extension. The patient is instructed to extend the thumb with flexing wrist to neutral from extended position. Patient is educated not to flex the wrist forcefully during this exercise. Any jerky or forceful movements ought to be avoided.

Soft tissue mobility techniques and oedema control are reinforced. Isolated movements are performed in a plane that is gravity-free during the first phase. Techniques for activating muscles include therapeutic whirlpool, mirror visual feedback, NMES, and biofeedback. Sessions are kept brief and within the limits of the patient's tolerance. In order to avoid fatigue and damage to the transferred muscle, the patients are advised to move slowly. The patient is instructed to wear an orthosis during the day at home and take it off only for exercises.

Phase 3: Rehabilitation Phase

Goals: Restore full active ROM, Achieve prehensile hand Function

If, by the eighth week following surgery, the patient can activate the transferred muscle without assistance, then he is ready for functional task practice and strengthening. The orthosis may be stopped during this phase or worn at night following the surgeon's instructions.

Thumb opposition and active wrist flexion is started gradually.

Upper extremity strengthening, resisted pinch, and grip exercises are added to the programme as per patient tolerance. It is also encouraged for the client to engage in everyday activities, recreational pursuits, and work-related activities. These training sessions are set up in a block, random, or serial format.

Prognosis

Prognosis is measured based on Range of Motion, Muscle strength, Functional outcomes and DASH score. Research reports better motor recovery with tendon transfers that nerve transfers except for finger extensions.