The Keller procedure is an excision arthroplasty of the 1st MTP joint, which can be used for both hallux rigidus and valgus. Most series contain a mixture,. It has the potential to create an unstable toe, particularly if bony resection is excessive or soft tissue repair neglected, but can give useful results in carefully selected patients if a good soft tissue repair is carried out.
Approach is normally dorsomedial or medial, protecting the cutaneous nerve. The capsule is opened longitudinally and flaps are carefully elevated to expose the joint and the proximal 1/3 of the phalanx.
The joint is debrided of osteophytes and synovitis. The proximal 1/3 of the proximal phalanx is excised, usually with a power saw. A careful repair of the capsular/periosteal sleeve is carried out, taking care to repair the transverse tie-bar of the forefoot at the correct tension. A Z-lengthening of the extensor hallucis longus is sometimes required to prevent “cock-up” deformity. Skin closure is as standard.
The patient can mobilise full-weightbearing immediately. There are no trials of different methods of aftercare. Strapping of the toe is common, aiming to achieve healing with a stable toe.
The Keller procedure was for many years the main procedure for hallux valgus in many surgeons' armamentarium, especially in the UK. It attained a reputation for defunctioned great toes, "cock-up" deformity and metatarsalgia. It has been argued that this reputation is at least partly due to a lack of attention to correct technique, especially soft-tissue balancing, and to many procedures being done by inadequately trained and supervised junior surgeons.
Most series (eg O'Doherty et al 1990, Blewitt and Greiss 1993) are mixed populations of hallux rigidus and valgus. With this reservation, Most series (eg O'Doherty et al 1990, Blewitt and Greiss 1993) are mixed populations of hallux rigidus and valgus. With this reservation, O'Doherty (1990) reported an RCT comparing Keller arthroplasty with fusion for arthritic 1st MTP joints, mostly with valgus deformity. Both procedures were equally effective in relieving pain in the 1st MTP joint and shoe fitting problems. Schneider and Knahr (2002) compared the results obtained by two surgeons in the same department in hallux valgus with HVA < 40deg, IMA <22deg and grade 1-2/3 degenerative change. One team used distal chevron osteotomy, the other Keller, and both carried out "cerclage fibreux" - lateral soft tissue release and medial capsular plication. The groups were similar except that the Kellers were slightly older, and follow-up was 5.7y. The mean final AOFAS hallux score was 85 in the Keller group and 83 for chevron. Radiological correction was comparable and there was only one cock-up toe in the Keller group. Metatarsalgia occured in 22% of chevrons and 20% of Kellers, and 92% of Keller patients and 94% of chevrons were satisfied.
The Keller is a useful operation for hallux valgus in certain circumstances:
- when the 1st MTP joint is severely arthritic
- when there has been significant infection and internal fixation hardware is considered an unacceptable risk
- in diabetics, who tend to get stiff Kellers which are stable
- as a salvage procedure
Further studies are needed to show whether well-balanced Kellers could have wider application.