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Management of Thumb Soft Tissue Defects / Amputations

- See:
       - Digit Reimplantation
       - Moberg Flap;
       - Tendon Injuries of the Thumb:
       - Second Toe Transfer:
       - Skin Grafts: for hand defects;

- Management of Acute Injuries:
    - amputations:
           - replantation:
                  - w/ amputations through the thumb IP joint, consider replantation and fusion;
           - amputation of the finger and hand:
                  - in contrast to amputations of a single finger, bone shortening and wound closure usually should not be considered for thumb soft tissue defects;
                         - in general, the thumb should never be shortened;
    - dorsal defects:
           - subcutaneous axial flap should be raised from the dorsal aspect of the proximal phalanx of the index finger;
           - tip amputations with more loss dorsally require a V-Y advancement flap;
    - palmar tip amputations:
           - Moberg Flap
                 - w/ loss that is more palmar but less than two thirds of the pulp are ideal for a Moberg Flap:
           - Crossed Finger Flap:
                 - w/ more than 2/3 of volar pulp loss, crossed finger flap from the index finger is appropriate;
                 - in this case, the flap will hinge off the radial side of the index finger;
                 - reference:
                       - Radial innervated cross-finger flap from index to provide sensory pulp to injured thumb.   
           - w/ loss that is palmar but is greater than 2/3 of the pulp should be treated with a neurovascular flap from the toe;

- Reconstructive Options for Established Injuries:
    - level of injury:
           - absence of thumb = 40% disability of hand as a whole;
           - injury at IP joint;
                  - no reconstruction may be required but wrap around method may be considered;
                  - references: Reconstruction of the thumb with a free wrap-around flap
           - injury to proximal phalanx (intact MP joint);
                  -  w/ amputation distal to MP joint, only the long flexor and extensor are lost;
                  - whole great toe transfer, 2nd toe transfer, or wrap around may be considered;
                  - deepen thumb web by Z plasty;
           - injury thru MP joint;
                  - great toe or 2nd toe transfer;
           - injury thru metacarpal;
                  - proximal to the MP joint, the intrinsic insertions and progressively their muscle bellies
                         are destroyed which leaves only the APL functioning at the metacarpal base;
                  - pollicization or 2nd toe transfer (when indicated)
                  - w/ a distal metacarpal injury, consider great toe transfer w/ a small portion of MP joint;
                  - w/ more proximal metacarpal injury, use a 2nd toe transfer;
           - injury at cmc level: pollicization;

- Specific Procedures:
    - digit reimplantation
    - toe to thumb transfer: (see: second toe transfer):
           - may be indicated to reconstruct the thumb after amputations from the level of the metcarpal base to the IP joint;
           - procedure is also indicated w/ hands w/ multiple injuries & amputations
           - first vs second toe transfer:
                  - usually the second toe is preferable in children and athletes, or in patients concerned about the appearance of the foot (such as women who wear sandles);
                  - transferred great toe has a better appearance than the second toe;
                  - great toe often has poor flexion ability where as second toe has poor extension ability;
                  - great toe may confer about 1/3 of normal strength (second toe confers on 15% of normal);
           - w/ amputation is proximal to the MP joint:
                  - there will no thumb intrinsic function which will thus require a tendon transfer;
                  - transfered MP joint tends to hyperextend and therefore must be restrained by capsulodesis or arthrodesis;
           - disadvantages:
                  - technically difficult procedure;
                  - vascular comprimise of hand may preclude the procedure;
                  - an adequate soft tissue cover (free of scar) is necessary prior to considering the procedure;
                  - most patients will require preoperative excision of scar and flap coverage and most patients will require at least one additional operation following the transfer;
                  - sensation recovery is slow and incomplete (75% of patients may expect 2 point of less than 10 mm at two years)
                  - cold tolerance remains a problem for most patients;
           - references:
                  - Free toe transfer for thumb and finger reconstruction in 300 cases.
                  - Ideas and Innovations: Toe-to-Thumb Transfer: A New Technique.
                  - Reconstruction of the hand with free microneurovascular toe-to-hand transfer: experience with 54 toe transfers.
                  - Toe-to-hand transfer
    - wrap around reconstruction:
           - references:
                  - Reconstruction of the thumb with a free wrap-around flap from the big toe and an iliac-bone graft.
                  - Thumb reconstruction by the wrap-around method.
                  - Resurfacing of the donor defect after wrap around toe transfer with a free lateral forearm flap.
    - lengthening:
           - with distraction metacarpal lengthening up to a 105 per cent increase can be achieved over several weeks;
           - alternatively, accept the distraction attained at surgery and insert a bone graft at the time;
           - references:
                  - Thumb reconstruction after amputation at the metacarpophalangeal joint by bone-lengthening. A preliminary report of three cases.  
                  - Thumb reconstruction after amputation at the interphalangeal joint by gradual lengthening of the proximal phalanx. A case report.
                  - The Gillies thumb lengthening operation.  
                  - Thumb reconstruction through metacarpal bone lengthening.  
- phalangization:
           - converts the metacarpal into a phalanx allowing increased space for grasp;
           - muscle recession:
                  - first dorsal interosseous is recessed by releasing the portion which arises from the thumb metacarpal;
                  - reattach adductor insertion from the sesamoid at the MP joint to a point further proximal on the metacarpal shaft;
           - deepening of the skin of the first web space:
                  - achieved w/ z-plasty (place on limb along the volar thenar crease, another along the ridge of the web space, and the last limb over the dorsum of the first metacarpal;
    - pollicization:
           - indicated for proximal thumb metacarpal amputations;
           - advantages:
                  - good appearance;
                  - potential for motion at all joints in the thumb;
                  - good sensibility;
           - disadvantages:
                  - a ray is removed which narrows the hand;
                  - expect some loss in grip strength;
                  - most patients w/ require more than one operation (such as web space deepening, tendolysis, rotational osteotomy);
                  - flap comprimise:
                         - may arise from damage sustained at the original trauma;
                         - consider arteriogram to determine vascular anatomy;
                  - incomplete digit rotation / insufficient web space:
                         - may result from scarring on the radial side of the hand, in which case, patients should be managed w/ appropriate soft tissue transfer to eliminate scarring;
                         - inadequate first dorsal interosseous muscle:                                  
                                - the first dorsal interosseous muscle will function as an opponens, and if it has been damaged, then a ring-FDS opponensplasty may be required;
           - references:
                  - Thumb reconstruction by digital transposition.  
                  - Pollicization after traumatic amputation of the thumb.  

Reconstruction of the thumb.

Reconstruction of the thumb with a free wrap-around flap from the big toe and an iliac-bone graft.

Per Primam thumb replantation for all patients with traumatic amputations.

One hundred eleven thumb amputations: replantation vs revision.

Survival factors in replantation and revascularization of the amputated thumb--10 years experience.

The choice of procedure following thumb amputation.

Transmetacarpal amputation of the index finger: A clinical assessment of hand strength and complications.

Thumb reconstruction after amputation at the metacarpophalangeal joint by bone-lengthening. A preliminary report of three cases.

Thumb reconstruction after amputation at the interphalangeal joint by gradual lengthening of the proximal phalanx. A case report.

Thumb reconstruction through metacarpal bone lengthening.

Adduction-flexion contracture of the thumb correction with dorsal rotation flap and release of contracture.

Dorsal pedicle flap for resurfacing a moderate thumb-index web contracture release.

Thumb web contracture

Medical and surgical importance of the arterial blood supply of the thumb.

Arterial anatomy and clinical application of the dorsoulnar flap of the thumb.