title: Gait Analysis of Foot Compensation After Arthrodesis of the First Metatarsophalangeal Joint.
abstract: BACKGROUND
  Arthrodesis of the first metatarsophalangeal (MTP1) joint is an intervention often used in patients with severe MTP1 joint osteoarthritis and relieves pain in approximately 80% of these patients. The kinematic effects and compensatory mechanism of the foot for restoring a more normal gait pattern after this intervention are unknown. The aim of this study was to clarify this compensatory mechanism, in which it was hypothesized that the hindfoot and forefoot would be responsible for compensation after an arthrodesis of the MTP1 joint.
  
  
  METHODS
  Gait properties were evaluated in 10 feet of 8 patients with MTP1 arthrodesis and were compared with 21 feet of 12 healthy subjects. Plantar pressures and intersegmental range of motion were measured during gait by using the multisegment Oxford Foot Model. Pre- and postoperative X-rays of the foot and ankle were also evaluated.
  
  
  RESULTS
  The MTP1 arthrodesis caused decreased eversion of the hindfoot during midstance, followed by an increased internal rotation of the hindfoot during terminal stance, and ultimately more supination and less adduction of the forefoot during preswing. In addition, MTP1 arthrodesis resulted in a lower pressure time integral beneath the hallux and higher peak pressures beneath the lesser metatarsals. A mean dorsiflexion fusion angle of 30 ± 5.4 degrees was observed in postoperative radiographs.
  
  
  CONCLUSIONS
  This study demonstrated that the hindfoot and forefoot compensated for the loss of motion of the MTP1 joint after arthrodesis in order to restore a more normal gait pattern. This resulted in a gait in which the rigid hallux was less loaded while the lesser metatarsals endured higher peak pressures. Further studies are needed to investigate whether this observed transfer of load or a preexistent decreased compensatory mechanism of the foot can possibly explain the disappointing results in the minority of the patients who experience persistent complaints after a MTP1 arthrodesis.
  
  
  METHODS
  Level III, comparative series.
authors: 1 Department of Orthopaedics, Maastricht University Medical Centre, The Netherlands.
authors: Jasper
authors: J
authors: Stevens
authors: 2 Department of Human Movement Sciences, Maastricht University, The Netherlands.
authors: Kenneth
authors: K
authors: Meijer
authors: 2 Department of Human Movement Sciences, Maastricht University, The Netherlands.
authors: Wouter
authors: W
authors: Bijnens
authors: 1 Department of Orthopaedics, Maastricht University Medical Centre, The Netherlands.
authors: Mathijs C H W
authors: MC
authors: Fuchs
authors: 1 Department of Orthopaedics, Maastricht University Medical Centre, The Netherlands.
authors: Lodewijk W
authors: LW
authors: van Rhijn
authors: 1 Department of Orthopaedics, Maastricht University Medical Centre, The Netherlands.
authors: Joris P S
authors: JP
authors: Hermus
authors: 3 Department of Surgery, Division of Trauma surgery, Maastricht University Medical Centre, The Netherlands.
authors: Sander
authors: S
authors: van Hoeve
authors: 3 Department of Surgery, Division of Trauma surgery, Maastricht University Medical Centre, The Netherlands.
authors: Martijn
authors: M
authors: Poeze
authors: 1 Department of Orthopaedics, Maastricht University Medical Centre, The Netherlands.
authors: Adhiambo M
authors: AM
authors: Witlox
mesh_terms: D000328:Adult; D000368:Aged; D001174:Arthrodesis; D016022:Case-Control Studies; D005260:Female; D033023:Foot Joints / Q000473:pathology / Q000502:physiology / Q000503:physiopathology*; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D008683:Metatarsophalangeal Joint / Q000601:surgery*; D008875:Middle Aged; D011859:Radiography; D016059:Range of Motion, Articular; D012016:Reference Values
keywords: MTP1 arthrodesis; Oxford Foot Model; compensatory mechanism; gait analysis; hallux; multisegment foot model; plantar pressure