First MTP Joint Decompression
- The Keller procedure is a RESECTION ARTHROPLASTY of the first metatarsophalangeal joint, performed by excising the BASE (the proximal third) of the PROXIMAL PHALANX of the hallux; this decompresses the arthritic or deformed first MTP joint, relieving pain and improving the alignment of a bunion (radiographs show a reduced intermetatarsal and first-MTP angle in many cases).
- Its INDICATIONS have narrowed over time: although historically used widely for hallux valgus and hallux rigidus, the Keller is now reserved largely for the LOW-DEMAND, ELDERLY patient with a painful arthritic and/or deformed first MTP joint (and sometimes for ulcerated/at-risk first MTP joints), and as a salvage option - it is generally avoided in young, active or high-demand patients.
- The fundamental TRADE-OFF is loss of HALLUX FUNCTION: resecting the base of the proximal phalanx detaches the plantar plate and the intrinsic (flexor hallucis brevis/sesamoid) mechanism and disrupts the windlass mechanism, so the hallux loses its PUSH-OFF and weight-bearing role, transferring load to the lesser metatarsals.
- The characteristic COMPLICATIONS follow from that trade-off: TRANSFER METATARSALGIA (pain under the lesser metatarsal heads from load transfer), a COCK-UP (dorsiflexion/hyperextension) deformity of the hallux, a flail, floppy or excessively short toe, recurrent valgus deformity, and cosmetic shortening - and although complications are common, in elderly low-demand patients pain relief and footwear tolerance are often still satisfactory.
- Because of these drawbacks, the Keller has been LARGELY SUPERSEDED for hallux valgus by corrective bunion OSTEOTOMIES and for hallux rigidus by CHEILECTOMY (early grades) and first MTP ARTHRODESIS (advanced disease, especially in active patients) - so the modern role of the Keller is the limited niche of the low-demand elderly patient.
- When a Keller FAILS - typically with recurrent valgus, a cock-up deformity, a flail toe or transfer metatarsalgia - the recommended SALVAGE is FIRST MTP ARTHRODESIS, which gives higher patient satisfaction and better clinical results than a repeat Keller or an isolated soft-tissue release (though it is technically demanding because of the bone loss and may need bone grafting to restore length).
- “Keller = resection arthroplasty of the first MTP - excise the BASE (proximal third) of the proximal phalanx of the hallux to decompress the joint.
- “Modern niche: LOW-DEMAND ELDERLY with hallux valgus / hallux rigidus (avoid in active/high-demand). Loses hallux push-off -> TRANSFER METATARSALGIA, COCK-UP deformity, flail/short toe, recurrent valgus.
- “Largely superseded by bunion osteotomies (HV) and cheilectomy/arthrodesis (hallux rigidus). Salvage of a failed Keller = first MTP ARTHRODESIS (better than repeat Keller).
Excise the base of the proximal phalanx to decompress the first MTP - now reserved for the low-demand elderly with hallux valgus/hallux rigidus (avoid in the active).
Loses hallux push-off -> transfer metatarsalgia, cock-up deformity, flail/short toe, recurrence. Failed Keller -> first MTP arthrodesis (salvage).
Procedure, Indication & Trade-off
The Keller procedure is a resection arthroplasty of the first MTP joint - excising the base (proximal third) of the proximal phalanx of the hallux to decompress an arthritic/deformed joint, relieving pain and improving bunion alignment. Its modern niche is the low-demand, elderly patient with a painful arthritic and/or deformed first MTP (hallux valgus or hallux rigidus), and as a salvage - it is generally avoided in active/high-demand patients. The trade-off is loss of hallux push-off: resecting the phalangeal base detaches the plantar plate and the intrinsic (flexor hallucis brevis/sesamoid) mechanism and disrupts the windlass, so load transfers to the lesser metatarsals. Hence the complications - transfer metatarsalgia, a cock-up (dorsiflexion) deformity, a flail/floppy/short toe, and recurrent valgus. It has been largely superseded by bunion osteotomies and by cheilectomy/arthrodesis for hallux rigidus, and a failed Keller is salvaged by first MTP arthrodesis.
| Procedure | Mechanism | Best for |
|---|---|---|
| Keller resection arthroplasty | Excise base of proximal phalanx (decompress) | Low-demand elderly (HV / hallux rigidus); salvage |
| Cheilectomy | Remove dorsal osteophyte/spur (preserve joint) | Early hallux rigidus (grade 1-2) |
| First MTP arthrodesis | Fuse the joint | Advanced hallux rigidus / active patients; failed Keller salvage |
| Bunion osteotomy | Realign the metatarsal/phalanx | Hallux valgus (active patients) |
Complications & Salvage
- Transfer metatarsalgia: loss of hallux weight-bearing transfers load to the lesser metatarsal heads - the commonest functional complaint.
- Cock-up (dorsiflexion) deformity of the hallux, and a flail/floppy or excessively short toe (from detachment of the intrinsics/plantar plate and over-resection).
- Recurrent valgus deformity and cosmetic shortening.
- Avoid in the active/high-demand patient (push-off loss is poorly tolerated); reserve for the low-demand elderly.
- Salvage of a failed Keller = first MTP arthrodesis (better satisfaction/results than a repeat Keller or soft-tissue release), often with bone graft to restore length - technically demanding because of the bone loss."
The Keller resection arthroplasty survives in modern practice only as a limited-niche operation, and the two errors to avoid are using it in the wrong patient and mismanaging its failures. Because resecting the base of the proximal phalanx destroys the hallux's push-off and weight-bearing role, it should NOT be offered to a young, active or high-demand patient - in whom it predictably causes transfer metatarsalgia and a weak, cock-up toe - and is instead reserved for the low-demand elderly patient with a painful arthritic or deformed first MTP, where pain relief and footwear tolerance are usually satisfactory despite the complications. When a Keller fails, with recurrent valgus, a cock-up deformity, a flail toe or transfer metatarsalgia, the reliable salvage is a first MTP arthrodesis rather than a repeat Keller; it is more technically demanding because of the bone loss and may need bone grafting, but it gives far better satisfaction. In active patients, bunion osteotomies (for hallux valgus) and cheilectomy or arthrodesis (for hallux rigidus) are the appropriate alternatives.
Evidence & Key Studies
Keller's arthroplasty in adults with hallux valgus and hallux rigidus
- In 32 patients (49 feet, mean age 62.5 years) with hallux valgus and hallux rigidus, Keller's resection arthroplasty gave satisfactory pain relief, cosmesis and footwear use, with excellent/good results in 87% by the Bonney-MacNab criteria.
- Radiographs showed a decrease in the intermetatarsal and first metatarsophalangeal angles in many cases.
- Complications were common but were not associated with the final result, and the amount of phalangeal-base resection was not associated with metatarsalgia or outcome.
Salvage of a failed Keller resection arthroplasty (arthrodesis vs motion-preserving)
- Typical complications of the Keller procedure include recurrent valgus deformity, cock-up deformity and a flail toe.
- First metatarsophalangeal arthrodesis as salvage achieved fusion in 26 of 29 feet with excellent/good satisfaction in 23, whereas a repeat Keller or isolated soft-tissue release gave excellent/good results in only 6 of 21 (with recurrent valgus/cock-up in most).
- Arthrodesis is recommended for salvage of a failed Keller because of its higher satisfaction and better clinical results.
According to PubMed, the satisfactory pain/cosmesis/footwear outcomes of Keller's arthroplasty in elderly adults with hallux valgus and hallux rigidus (with reduced IM/MTP angles, and complications not predicting the result) come from the cited Putti series; the typical complications (recurrent valgus, cock-up deformity, flail toe) and the superiority of first MTP arthrodesis over a repeat Keller/soft-tissue release for salvage from the cited Machacek study. The mechanism (resection of the proximal phalangeal base disrupting push-off, causing transfer metatarsalgia), the modern restriction to low-demand elderly patients, and the alternatives (cheilectomy, arthrodesis, bunion osteotomy) are standard, well-established teaching. (See also our Hallux Rigidus and Hallux Valgus topics.)
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“What is the Keller procedure and what is its modern role?”
“How would you salvage a failed Keller arthroplasty?”
Mnemonics & Memory Aids
KELLER
Hook:KELLER: Knock off the phalangeal base, Elderly low-demand niche, Loses push-off, Lesser-MTP transfer metatarsalgia, Erect (cock-up) toe, Rescue with arthrodesis.
Procedure
- Resection arthroplasty of the first MTP joint
- Excise the base (proximal third) of the proximal phalanx of the hallux
- Decompresses the joint; reduces IM/MTP angles in many cases
Indication (modern)
- Low-demand elderly with painful arthritic/deformed first MTP (HV / hallux rigidus)
- Salvage option
- Avoid in young/active/high-demand patients
Complications
- Transfer metatarsalgia (lost push-off -> lesser-MTP overload)
- Cock-up (dorsiflexion) deformity; flail/floppy/short toe
- Recurrent valgus; cosmetic shortening
Alternatives & salvage
- Cheilectomy (early hallux rigidus); first MTP arthrodesis (advanced/active); bunion osteotomy (HV)
- Failed Keller -> first MTP arthrodesis (better than repeat Keller)
- Often needs bone graft to restore length at salvage