- 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;
-
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. PT Fortin and MS Myerson. Foot Ankle Int. Vol 16. 1995. p 306-313.
- Subluxation and dislocation of the second MP joint. MJ Coughlin. Orthop. Clin. North Am. Vol 20. 1989. p 535-551.
- 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;
- alternatively, the FDL tendon may have to be released;
- instead of K wires, secure the PIP in extension, w/ horizontal matress retension sutures tied over a bolsters (either rubber or telfa);
- 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;
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
