Tendon Transfer Surgery: Risks & Benefits

Hand Foot Infections And Tendon Transfer

Define and describe the aetiology and pathogenesis of surgical infections.

Surgical Infections Introduction

Hand infections are commonly encountered in manual labourers and are precipitated by injury, such as a thorn prick, cut injuries, etc. In 80–90% of cases, the causative organism is Staphylococcus aureus sensitive to cloxacillin.

Read And Learn More: General Surgery Notes

• In the remaining cases, streptococci, gram-negative bacilli, or anaerobic organisms may play a role. Irrespective of the site of infection, oedema is commonly present on the dorsal aspect because of the following reasons:
• Lymphatics from the palmar aspect of the hand travel through the dorsal aspect to the corresponding lymph node.
• Presence of loose areolar tissue in the dorsum of the hand.
  • Hand infections may be severe in immunocompromised, systemically ill, and diabetic patients. It may spread rapidly and cause septicaemia and death.
  • It is unfortunate that in cases of gas gangrene and spreading infections, amputation may have to be done

Classification Of Hand Infections

Superficial Infections Paronychia

It refers to an infection near the nail. It is the most common type of hand infection. There are two types—acute and chronic.

Acute Paronychia

It occurs due to trimming of the nail or an ingrowing nail.

• The subcuticular infection starts in the lateral sulcus and spreads all around (paronychia means ‘run around’). This is because the eponychium (skin overlying the nail base) is adherent to the nail base.
• Hence, the infection spreads beneath the nail base. The affected finger is painful. Throbbing pain suggests the presence of pus. Even a collection of 0.5 ml of pus produces severe pain. Low-grade fever may be present.

Acute Paronychia Treatment

Early cases (before the formation of pus) may be managed by soaking, elevation, antibiotics, and immobilisation.

• After a digital block (with 5 ml of 2% plain lignocaine injected into the root of the digit), incision and drainage are done by incising the eponychium. Adrenaline should not be used for infiltration in the finger, penis, or ear lobule.
• These areas are supplied by end arteries (no collateral circulation). Adrenaline is a vasoconstrictor and may cause gangrene. Pus is sent for culture and sensitivity. Antibiotics are given. Dressings are applied.

Chronic Paronychia

It is not due to bacterial infection, but due to fungal infection—moniliasis or Candida.

• It is common in women who wash clothes, utensils, etc. and constantly have wet fingers. As a result of this, fungal infection takes place. The infection is insidious in onset, chronic, and difficult to eradicate. It produces a dull nagging pain in the fingers. The eponychium is faintly pink and the nail is ridged.
• Antifungal agents such as nystatin or tolnaftate solution help the patient. Rubber gloves should be worn while using hands for washing.

Subcutaneous Infections

Intraepidermal abscess (purulent blister): Cuts, pricks, and burns may cause this condition.

1. Intradermal abscess: This variety does not produce a dome-shaped elevation.
2. Subcutaneous abscess: This type of lesion is like that of cellulitis.
3. Collar-stud abscess: It results when the epidermal component is connected to the dermal component.

Subcutaneous Infections Treatment

Incision and drainage under an antibiotic cover. Care should be taken to drain the deeper cavity.

Acute Lymphangitis Of The Hand

It is caused by an injury, which may be a minor abrasion. The causative organism is Streptococcus.

Acute Lymphangitis Of The Hand Clinical Features

Severe pain in the hand with fever, chills, and rigours.

• Gross oedema of the dorsum of the hand.
• Red, hot streaks over the limb indicate the route of lymphatics.
• Regional lymph nodes are swollen and tender.
• • Infection of little finger—epitrochlear nodes are enlarged.
  • Infection of the ring and middle fingers—supraclavicular nodes are enlarged.
  • Infection of index and thumb fingers—axillary nodes are enlarged.

Acute Lymphangitis Of The Hand Treatment

• Injection of crystalline penicillin 10 lakh units 4 or IM for 5–7 days.
• Higher antibiotics may have to be used, depending on the response.

Acute Lymphangitis Of The Hand Herpetic Whitlow

• It is due to herpes simplex virus (HSV).
• Common in children, may follow herpetic gingivostomatitis.
• The most common viral infection of the hand—the distal finger.
• Pain, pruritus, and vesicles are characteristics. Fever and lymphadenitis are present.
• It resolves spontaneously.
• The diagnosis is mainly clinical. However, culturing the virus from the vesicular fluid, assessing immunofluorescent serum antibody titres, or performing a Tzanck smear may confirm the diagnosis.
• Antivirals such as acyclovir or famciclovir are of some benefit if started within 48 hours.

Deep Infections Infection Of The Terminal Pulp Space (Felon)

This space commonly gets infected due to relatively deep prick injuries. It is the second most common infection of the hand, seen in about 25% of patients.

Anatomy of the Terminal Pulp Space

It is a closed space, formed by the fusion of the distal flexion skin crease and the deep fascia attached to the periosteum of the distal phalanx, just distal to the insertion of flexor digitorum profundus.

• Each pulp space is subdivided by the presence of numerous septa which pass from the deep fascia to the periosteum. Thus, 15–20 small compartments are formed.
• The digital artery, which is an end-artery, runs in this closed space.

Deep Infections Infection Of The Terminal Pulp Space Clinical Features

• Injury to the affected finger is usually present. The thumb and index fingers are commonly involved.
• Throbbing pain is worse in the dependent position, with nocturnal exacerbations.
• An indurated, red, and tense pulp space is characteristic of this condition.
• Touch and movement worsen the pain.

Terminal Pulp Space Infection—Felon

• Fingertip pulp abscess
• Extremely painful
• Loss of normal resilience of pulp
• Osteomyelitis of the distal phalanx in untreated cases due to thrombosis of the digital artery
• No longer recommended fish mouth incision
• Remember as FELON

Deep Infections Infection Of The Terminal Pulp Space Treatment

Incision and drainage under digital block—volar longitudinal incision.

Deep Infections Infection Of The Terminal Pulp Space Complications

1. If the pus is not released early, thrombosis of the digital artery takes place, resulting in osteomyelitis and necrosis of the terminal phalanx, which may result in the shortening of the finger.
2. Pyogenic arthritis of the distal interphalangeal joints.
3. Tenosynovitis is secondary to pus, which requires regular physiotherapy to avoid the development of thickness.
4. Neuroma, which may be painful and cause discomfort.

Apical Subungual Infection

• Infection is confined to the space between the distal quarter of the subungual epithelium and the periosteum of the distal phalanx. Penetration by a sharp object causes this condition. It often manifests as a tender yellow spot beneath the distal portion of the nail. Pain, redness, and minimal swelling are the features.
• Tenderness is maximum at the free edge of the nail. The pulp and distal parts of the fingers are relatively painless. It is treated by a “V” excision of a portion of the nail to open the abscess cavity under an antibiotic cover.

Middle And Proximal Volar space infections

• These spaces are loose in comparison to the terminal pulp spaces. They are filled with fibrofatty tissue.
• The middle volar space is closed but proximally communicates with web space.
• The swelling is tender and indurated. The finger is held in flexion.
• It is treated by a transverse incision and drainage of the pus.

Web Space Infections

Web spaces are the triangular spaces between the four divisions of the palmar aponeurosis. There are 3 in number. The thumb has no palmar aponeurosis. They are filled with subcutaneous fat and are covered posteriorly by the metacarpal bones.

Web Space Infections

• 3 web spaces
• Finger separation sign
• Gross oedema of dorsum
• Spread to other web space

Causes of Web Space Infection

• Penetrating injuries
• Spread of a proximal volar space (palmar space) infection.
• Lumbrical canal infection—suppurating tenosynovitis.

Web Space Infections Clinical Features

• Pain and swelling of the palm in the region of the web space.
• Extremely tender and hot swelling.
• Finger separation sign: Adjacent fingers are separated due to oedema.
• Gross oedema of the dorsum of the hand.
• If untreated, pus from one web space may spread to other web spaces and or to the proximal volar space.

Web Space Infections Treatment

Under anaesthesia, a transverse skin incision is made and the pus is drained. The cavity is treated like any other abscess cavity. The skin edge is trimmed to leave a diamond-shaped opening behind for better drainage.

Midpalmar Space Infection Or Deep Palmar Abscess

Infection of the mid-palmar space results in a deep palmar abscess.

• The mid-palmar space is the space behind the palmar aponeurosis and in front of the metacarpal bones.
• Since the palmar fascia is thick, strong, and unyielding, pus collects deep into the palmar fascia. If it is due to penetrating injuries, it collects in the subcutaneous plane like a collar-stud abscess. In the centre of the palm, there is no subcutaneous tissue. Hence, pus collects beneath the thick dermis.

Surgical Anatomy Of The Palmar Fascia And Aponeurosis

• The central, thick, fibrous part of the palmar fascia is the palmar aponeurosis.
• The palmar fascia covers the long flexors.
• The apex of the triangular palmar aponeurosis is continuous with the flexor retinaculum and the palmaris longus tendon.
• Distally, it forms 4 longitudinal digital bands that attach to the bases of the proximal phalanges.
• Two (medial and lateral) fibrous septa extend from the medial and lateral margins of the palmar aponeurosis. The septa are attached to the 5th and 3rd metacarpals, respectively.
• Deep to the flexor tendons, digital arteries and nerves lie in the midpalmar space.
• The midpalmar space is continuous with the anterior compartment of the forearm via the carpal tunnel.
• This space is called the ‘space of Parona’.

Surgical Anatomy Of The Palmar Fascia And Aponeurosis Source Of Infection

• Penetrating injuries
• Haematoma
• Suppurative tenosynovitis

Source Of Infection Clinical Features

• Obliteration of the normal concavity of the palm
• Gross oedema of the dorsum of the hand
• Extreme tenderness in the mid-palmar space
• Fingers are held in flexion at the metacarpophalangeal (MP) joint because the palmar aponeurosis gets relaxed in this position. MP joint movements are painful.
• IP (interphalangeal) joint movements are not painful.

Source Of Infection Treatment

• Under anaesthesia, a transverse crease incision is made until the palmar aponeurosis is seen, which is split longitudinally in the direction of the fibres to avoid damage to the nerves and vessels.
• The abscess cavity is treated in the usual manner.

Acute Suppurative Tenosynovitis

Surgical Anatomy Of The Flexor Tendon Sheath Arrangements

• The flexor tendon sheaths which enclose the tendons run along the entire length of the finger. In the palm, the medial tendons are enclosed by a common synovial pocket called the “ulnar bursa,” whereas the lateral tendons are enclosed by the “radial bursa.”
• These two bursae communicate in 75% of the cases. In 25% of the cases, the flexor tendon sheath of the thumb communicates with the radial bursa, and that of the little finger communicates with the ulnar bursa.
• Thus, infection flexor tendon sheaths may involve the entire hand.
• The flexor tendon sheaths extend from the base of the terminal phalanges to the heads of the metacarpal bones.

Acute Suppurative Tenosynovitis Clinical Features

• The patient gives a history of a pricking injury.
• Symmetrical, fusiform, painful enlargement of the fingers.
• Fixed, flexed fingers—‘Hook sign’
• IP joint movements are very painful: Severe pain on passive finger extension.

Suppurating Tenosynovitis

• • Sharp prick injuries
  • Hook sign—bent finger
  • IP joint movements painful
  • MP joint movements need not be painful
  • ‘Kanavel’s sign’
• MP joint movements are not painful: This sign differentiates suppurating tenosynovitis from a deep palmar abscess.
• Similarly, when there is an infection of the radial bursa, there is tenderness over the lateral side, and over the flexor pollicis longus sheath.

Acute Suppurative Tenosynovitis Kanavel’s Four Cardinal Signs of Flexor Tenosynovitis

• The finger is held in flexion because this increases the volume of the synovial sheath and eases pain.
• Symmetrical fusiform swelling of the entire finger.
• Passive extension of the affected digit produces exquisite pain.
• Maximum tenderness is at the proximal cul-de-sac of the synovial sheath of the index, middle, and ring fingers in the distal palm.

Kanavel’s Four Cardinal Signs of Flexor Tenosynovitis Treatment

• Under anaesthesia, multiple incisions may have to be given to decompress the flexor tendon sheaths to relieve tension and drain the pus, exudate, etc.
• The cavity is irrigated with an antiseptic solution.
• In severe cases, a small plastic catheter should be introduced into the synovial bursa and should exit by a counter-incision in the palm for antibiotic irrigation.
• Postoperatively, appropriate antibiotics should be given for about 2 weeks.
• The hand should be in an elevated position to reduce oedema.

Kanavel’s Four Cardinal Signs of Flexor Tenosynovitis Complications

1. Stiffness of the fingers
2. Suppurating arthritis of the joints
3. Osteomyelitis
4. Loss of tendon, digit
5. Spread of infection to space of Parona. It is the space deep to the flexor profundus and superficial to the pronator quadratus in the lower end of the forearm. Patients present with swelling of the forearm along with gross oedema of the hand.
6. In addition to the treatment mentioned above, a separate incision may have to be given in the lower forearm for better drainage of pus.

General Principles Of Hand Infection Management

• Early diagnosis and splinting.
• Early proper drainage
• Proper incision—preferably a crease incision
• Elevation of the hand to reduce oedema
• Pus culture and sensitivity
• Cloxacillin 500 mg 6th hourly and metronidazole 400 mg 8th hourly for 7–10 days. Higher antibiotics such as cephalosporins may have to be given.
• Physiotherapy to decrease the stiffness of the fingers.
• Tetanus prophylaxis in high-risk patients.

Recommended Antibiotics

Staphylococcus aureus: First-generation cephalosporins.

An aerobics or Escherichia coli: Clindamycin or β-lactamase inhibitors, amoxicillin clavulanate potassium.

Herpetic Whitlow: Antivirals.

Position of Hand Functions

• The hand is held as if holding a cup/glass, with the thumb in alignment with the forearm.
• Extension at wrist: 25°
• Flexion at metacarpophalangeal joint: 60°
• Flexion at interphalangeal joint: 10°
• Flexion at distal interphalangeal joint: 5°.

Other Hand Infections

1. Compound palmar ganglion.
2. Barber’s pilonidal sinus (interdigital): It occurs due to repeated clipping by barbers.
3. Orf virus infections: It is also called ecthymacontagiosum, highly contagious pustular dermatitis due to parapoxvirus infection. It is endemic in sheep and goat herds worldwide. It is transmitted by direct contact.
4. Lesions cannot only occur in hands but also in lips, ears nostrils, etc. Typically, it appears as an ulcerated nodule which is red in colour. It is a self-limiting course, which may take 1 to 2 months.
5. Milker’s nodes: A viral disease transmitted by handling a cow’s udder. Milker’s nodules (pseudo cowpox) are harmless skin lesions most commonly seen in persons whose occupation regularly brings them into close contact with cattle.
6. Lesions are multiple swellings with central ulceration. Like any other hand infection, there is oedema of the hands. Treatment is symptomatic.
7. Human bites: Common organism is Staphylococcus. The wound is explored, and proper treatment is given.
8. Atypical mycobacterial infections: It affects tendon sheaths resulting in swelling, stiffness, pain, and redness. Fever can also be a feature. Diagnosis is by exploration and excision of the infected tendon sheath lining.
9. The histopathological examination should include not only looking for granulomas but also gene experts for Rifampicin resistance. Mycobacterium marinum is the common cause.

 

Tendon Transfer

Tendon transfer surgeries are a highly useful form of reconstruction wherein the actions of lost or weakened neuromuscular action are supplemented or substituted by redirecting the action of other intact and relatively expendable musculo-tendinous units.

• Thus, certain actions and abilities that are deemed more important are reconstructed at the expense of others. Several of these procedures have been described, developed, and popularized by Indian surgeons such as Paul Brand, Srinivasan, Fritchie, and Antia among others.
• The surgical techniques and principles of tendon transfer underwent a lot of development under these illustrious surgeons, especially for the treatment of nerve palsy from Hansen’s disease which used to be endemic to certain parts of our country.
• All tendon transfer surgeries follow certain principles which are paramount to the success of these highly sophisticated and technically demanding procedures. They require accurate realignment of the direction of force of the transferred.
• Musculotendinous unit as well preservation of transferred elements with minimal damage to the donor tissue. The success of the procedure also requires that both the surgeon.

The patient understands the functional and aesthetic goals along with the limitations and expectations of surgery. The basic principles of tendon transfer are as follows:

1. Supple joints prior to transfer: Prior to the procedure, the joint that the tendon transfer will move must be supple and have a maximum x range of motion when moved passively.

2. Soft tissue equilibrium: The tissues through which the tendon transfer is negotiated must be healthy and free of any oedema, inflammation or scar. These may hinder tendo-muscular glide and optimal wound healing following tendon transfer.

3. Donor of adequate excursion: The maximum linear movement of the transferred Musculo-Tendinous Unit (MTU) or its change in length on contracting or relaxing should be adequate to achieve the desired hand movement.

• • The MTU chosen for transfer should ideally have an excursion similar to that of the tendon that it is replacing.

4. Donor of adequate strength: The MTU to be transferred must be strong enough to achieve the desired movement, but at the same time, should not be too strong. A donor MTU that is too weak will have inadequate movement and function.

• • while a donor that is too strong will result in imbalanced movement and inappropriate posture at rest. Thus, the MTU chosen for transfer should ideally have strength similar to that of the tendon which it is replacing.

5. Expendable donor: Use of a potential donor MTU for transfer, may result in some degree of weakness, loss of movement, or imbalance. These must not be more debilitating than the function it is replacing.

• • Further, the choice of the donor MTU should preferably be those which have other MTUs that serve a since purpose or perform similar actions.

6. Straight line of pull: Tendon transfers are most effective if the MTU provides a straight line of pull. Direction changes diminish the force that the transferred MTU is able to exert on its insertion. However, a change of direction may be required in a few cases and utilize pulleys to bring about this directional change.

7. Synergy: Muscle groups (finger flexors or wrist extensors) usually work together to perform a function or movement. MTU utilized for transfer must be synergistic to the function it is replacing with rare exceptions. Thus, extensors are not used to replace flexor actions and vice versa.

8. Single function per transfer: It is ideal to attempt achieving just a single function out of a single MTU transfer. Every transfer will result in compromised strength and movement. There is an inherent tendency to lose at least one grade of power (MRC grade) when a tendon transfer is performed.

Tendon Transfer References

1. Tendon Transfers Part I: Principles of Transfer and Transfers for Radial Nerve Palsy. Douglas M. Sammer, MD1 and Kevin C. Chung, MD, MS2.
2. Green’s Operative Hand Surgery, 2-Volume Set, 8th Edition