title: Mid-term functional outcome of a total arthroplasty of the first metatarsophalangeal joint.
abstract: BACKGROUND
  Arthroplasty of the first metatarsophalangeal joint is an alternative treatment option for end-stage hallux rigidus to the current gold standard of arthrodesis. The aim of this study was to investigate the mid-term functional outcome of an anatomically shaped prosthesis for the first metatarsophalangeal joint using pedobarography.
  
  
  METHODS
  Ten patients (12 affected feet; age at surgery: 62.1 (SD: 7.2) years) were investigated preoperatively and 52 (SD: 3) months postoperatively using pedobarography (EMED, novel GmbH, Munich, Germany). Two patients were excluded at follow-up because their prosthesis was converted to an arthrodesis. Peak force and plantar pressure under the five metatarsal heads and the hallux were analyzed and correlated with the clinical outcome (pain, American Orthopaedic Foot and Ankle Society forefoot score and radiographic maximum first metatarsophalangeal dorsiflexion). Differences between pre- and postoperative data were analyzed using paired t-tests (alpha=0.05).
  
  
  RESULTS
  Postoperatively, forefoot peak forces under the fourth (+40.9%; P=0.018) and fifth metatarsal (+54.9%; P=0.037) and plantar pressures under the fifth metatarsal (+38.7%; P=0.027) increased significantly, while peak plantar pressures and forces under the hindfoot, medial forefoot and hallux did not change. While maximum passive dorsiflexion was not significantly greater at the 4-year follow-up compared to preoperatively, overall greater passive dorsiflexion was associated with higher first metatarsal peak pressure.
  
  
  CONCLUSIONS
  Despite of patients reporting less pain, the functional results indicate an altered and potentially non-physiological postoperative gait pattern with a lateralization of the load during walking, especially in patients with limited passive dorsiflexion.
authors.affiliation: University of Basel, University Hospital, Orthopaedics and Traumatology, Switzerland; University of Basel, Department of Biomedical Engineering, Switzerland. Electronic address: corina.nueesch@usb.ch.
authors.forename: Corina
authors.initials: C
authors.lastname: Nüesch
authors.affiliation: University of Basel, University Hospital, Orthopaedics and Traumatology, Switzerland; University of Basel, Department of Biomedical Engineering, Switzerland.
authors.forename: Annegret
authors.initials: A
authors.lastname: Mündermann
authors.affiliation: University of Basel, University Hospital, Orthopaedics and Traumatology, Switzerland.
authors.forename: Monika
authors.initials: M
authors.lastname: Horisberger
mesh_terms: D001178:Arthroplasty; D005260:Female; D005684:Gait / Q000502:physiology; D006214:Hallux / Q000503:physiopathology / Q000601:surgery; D020859:Hallux Rigidus / Q000503:physiopathology* / Q000601:surgery*; D006801:Humans; D008297:Male; D008682:Metatarsal Bones / Q000502:physiology; D008683:Metatarsophalangeal Joint / Q000503:physiopathology* / Q000601:surgery*; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology; D011312:Pressure; D011446:Prospective Studies; D016896:Treatment Outcome
keywords: Hallux rigidus; Metatarsophalangeal joint; Pedobarography; Total joint replacement