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Hammer Toes


- Anatomy and Discussion:
    - term describes abnormal flexion posture of PIP joint of one of lesser 4 toes;
    - the hammer toe deformity is similar to the curly toe deformity but is not malrotated;
    - flexion deformity of PIP may be fixed or supple;
    - w/ severe hammer toe deformity, MP joint may go into hyperextension (distal joint usually stays supple);
    - pathogenesis:
          - may involve contracture of FDL tendon;
                 - when this is the case look for a dynamic deformity, ie., the hammer toe is worse when the patient stands or walks;
          - long second metatarsal may be a predisposing factor;
          - high heels and crowded shoe wear are also common causes;
          - less common causes are RA, cross over deformity, diabetes;
          - in rare cases hammer toe deformity may be due to plantar fascia release;
    - w/ MP joint contracture, contracture of EDL may prevent the MP joint from obtaining a neutral position;
          - main action of the EDL is to dorsiflex the phalanx, but can only do so when the phalanx is in a neutral or flexed position; 
          - ref: Definitions of hammer toe and claw toe: an evaluation of the literature
    - diff dx:
          - interdigital neuroma 
          - claw toes
          - mallet toe
          - non specific synovitis:
                 - tends to involve second metatarsophalangeal joint;
                 - occurs spontaneously in women and results in pain and disability;
                 - if long metatarsal is a strong risk factor, and the EHL/EDL is the most important dynamic deforming force;
                 - it usually subsides after 3 to 6 months, but may go on to frank dorsal subluxation;
                        - w/ dorsal dislocation, there will usually be attenuation of the volar plate;
                 - after it has subsided patient may be left with subluxated MTP joint & fixed hammer toes deformity;
                 - w/ cross-over toe deformity look for tight medial collateral ligament, and plantar skin changes;
                        - taping of toes may prevent further deformity but will not reverse deformity;
                 - references:
                        - Traumatic horizontal deviation of the second toe: mechanism of deformity, diagnosis, and treatment.
                        - Second metatarsophalangeal joint instability.   
                        - Subluxation and dislocation of the second metatarsophalangeal joint.


- Physical Exam:
    - look for callus formation over dorsum of PIP joint and/or at the volar tip of the toe (just under the nail);
    - determine if hammer toe is made worse w/ walking (hammer toes are usually accentuated by standing, when intrinsics are relaxed);
    - distinguish between supple and fixed hammer toe;
           - it has been suggested that pressure on the plantar aspect of the metatarsal heads will cause toe extension in supple hammer toes;
           - if the hammer toe is due to contracture of FDL tendon, then plantar flexion of the ankle will straighten the toe;
                  - dorsiflexion of the ankle, in contrast, will worsen the deformity;
    - stability of MP joint:
           - apply an anterior and posterior drawer test to determine stability;


- Non Operative Treatment:
    - if deformity is of recent onset, one can use pads over corns & have patient perform daily stretching of the PIP joint;
    - hammer toe straightening orthotics are also available;


- Operative Treatment:
    - hallux valgus must be corrected prior to correction of hammer toes (pressure from the big toe is deforming force for hammer toes);
    - hammer toe can be corrected by transfer of FDL to EDL tendon over mid-portion of proximal phalanx, which serves to augment intrinsic function (MTP flexion & IP extension);

- Mild Deformity:
    - implies no fixed contracture at MP or PIP joint, but deformity increases on wt bearing;
    - consider isolated tenotomy of the FDL tendon;
    - Girdlestone Taylor Procedure: may or may not be appropriate indicated for a young adult with a mild deformity;
            - this procedure may cause the base of the toe to remain swollen (or fat) giving a poor cosmetic appearance;
            - this procedure may cause the toe to remain too straight again causing a poor cosmetic appearance;

- Moderate Deformity:
    - there is fixed or partially fixed contracture at PIP joint, & mild extension contracture at MP joint;
    - Girdlestone Taylor Procedure: may be more appropriate for moderate hammertoe deformity; 
    - PIP arthroplasty / arthrodesis;
            - anesthesia: IV sedation and local block;
            - make and eliptical transverse incision over dorsal PIP joint;
            - expose and transect: the extensor tendon, joint capsule, and collateral ligaments;
            - resect of head & neck of proximal phalanx w/ rongeur or saw;
            - it is controversial as to whether the FDL tendon should be exposed, split in half, and transferred around either side of the phalangeal neck; 
            - suture bolster: secure the PIP in extension, w/ horizontal matress retension sutures tied over a bolsters (either rubber or telfa); 
                   - reference:
                         - Review of proximal interphalangeal joint excisional arthroplasty for the correction of second hammer toe deformity in 100 cases.
            - K wire fusion:
                   - FDL tendon is left intact and after PIP fusion, it will act to depress the digit;
                   - references:
                         - Radiographic analysis of proximal interphalangeal joint arthrodesis with an intramedullary fusion device for lesser toe deformities.
                         - Arthrodesis of the toe joints with an intramedullary cannulated screw for correction of hammertoe deformity.
                         - Advantages and drawbacks of proximal IP joint fusion versus flexor tendon transfer in the correction of hammer and claw toe deformity
                         - Finite-element simulation of flexor digitorum longus or flexor digitorum brevis tendon transfer for the treatment of claw toe deformity.
                         - Second metatarsophalangeal joint fusion: a new technique for crossover hammertoe deformity. A preliminary report

- Severe Deformity:
    - involves fixed flexion contracture at PIP joint w/ fixed extension contracture of MP joint (or subluxation / dislocation) of base of proximal phalanx on MT head;
    - in addition to PIP arthroplasty (see above), w/ hyperextension at MTP joint sequentially release the following:
           - perform extensor tenotomy (EDL);
           - release of dorsal MTP capsule;
           - collateral ligament release if needed for MTP joint reduction (down to volar plate);
           - intrinsic release
           - for dislocations of the MTP joint, an MTP resection arthroplasty is performed;
    - w/ fixed PIP and MTP deformities, K wire stabilization is required for 3 weeks;
    - inform pt that toe ischemia sometimes follows correction of severe deformity; 
    - ref: Correction of hammer toe with an extended release of the metatarsophalangeal joint



The pathological anatomy of claw and hammer toes

Results of phalangectomy of the fifth toe for hammertoe. The Ruiz-Mora procedure.

Metatarsal neck osteotomy with proximal interphalangeal joint resection fixed with a single temporary pin.

Review of proximal interphalangeal joint excisional arthroplasty for the correction of second hammer toe deformity in 100 cases.

Transfer of the Flexor Digitorum Longus for the Correction of Lesser-Toe Deformities

Correction of crossover deformity of second toe by combined plantar plate tenodesis and extensor digitorum brevis transfer: a minimally invasive approach

The role of toe flexor-to-extensor transfer in correcting metatarsophalangeal joint instability of the second toe.

Combined plantar plate and hammertoe repair with flexor digitorum longus tendon transfer for chronic, severe sagittal plane instability of the lesser metatarsophalangeal joints: preliminary observations.

Transfer of the flexor digitorum brevis tendon

Flexor tendon transfer for metatarsophalangeal instability of the second toe.

Surgical treatment of patients with painful instability of the second metatarsophalangeal joint

Modified plantar plate tenodesis for correction of claw toe deformity.

Advantages and drawbacks of proximal interphalangeal joint fusion versus flexor tendon transfer in the correction of hammer and claw toe deformity. A finite-element study.

Finite-element simulation of flexor digitorum longus or flexor digitorum brevis tendon transfer for the treatment of claw toe deformity.

Dorsal approach to transfer of the flexor digitorum brevis tendon.

Definitions of hammer toe and claw toe: an evaluation of the literature

Modification of lesser metatarsophalangeal joint arthroplasty using flexor digitorum longus transfer.

Arthroscopic-assisted correction of claw toe or overriding toe deformity: plantar plate tenodesis

Review of proximal interphalangeal joint excisional arthroplasty for the correction of second hammer toe deformity in 100 cases.

Correction of hammer toe with an extended release of the metatarsophalangeal joint.

Transfer of the flexor digitorum longus for the correction of lesser-toe deformities

A retrospective analysis of modification of the flexor tendon transfer for correction of hammer toe.

Prospective review of medium term outcomes following interpositional arthroplasty for hammer toe deformity correction.

Dorsal suspension stitch: an alternative stabilization after flexor tenotomy for flexible hammer digit syndrome

Correction of fixed hammertoe deformity with resection of the head of the proximal phalanx and extensor tendon tenodesis

Selective lengthening of the proximal flexor tendon in the management of acquired claw toes.

Hammertoe surgery: waist resection of the proximal phalanx, a more simplified procedure.