title: Changes in knee joint load indices from before to 12 months after arthroscopic partial meniscectomy: a prospective cohort study.
abstract: Patients undergoing arthroscopic partial meniscectomy (APM) are at increased risk of knee osteoarthritis (OA). Meniscal damage and/or surgery may alter knee joint loading to increase OA risk. We investigated changes in knee joint loading following medial APM surgery, compared with the contra-lateral leg.
  
  
  
  We estimated indices of knee joint loading (external peak knee adduction moment (KAM), KAM impulse and peak knee flexion moment (KFM)) normalized to body size (i.e., body mass (BM) and height (HT)) using 3D gait analysis in 23 patients (17 men, mean (SD) 46.2 (6.4) years, BMI 25.8 (3.4) kg/m(2)) without radiographic knee OA before and 12 months after medial APM. Static alignment was assessed by radiography and self-reported outcomes by Knee injury and Osteoarthritis Outcome Score (KOOS).
  
  
  
  Peak KAM and KAM impulse increased in the APM leg compared to the contra-lateral leg from before to 12 months after surgery (change difference: 0.38 Nm/BM*HT% 95% CI 0.01 to 0.76 (P = 0.049) and 0.20 Nm*s/BM*HT% 95% CI 0.10 to 0.30 (P < 0.001)). Patients self-reported improvements on all KOOS subscales (KOOS pain improvement: 22.8 95% CI 14.5 to 31.0 (P < 0.01)).
  
  
  
  A relative increase in indices of medial compartment loading was observed in the leg undergoing APM compared with the contra-lateral leg from before to 12 months after surgery. This increase may contribute to the elevated risk of knee OA in these patients. Randomized trials including a non-surgical control group are needed to determine if changes in joint loading following APM are caused by surgery or by changes in symptoms.
authors.affiliation: Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark. Electronic address: jthorlund@health.sdu.dk.
authors.forename: J B
authors.initials: JB
authors.lastname: Thorlund
authors.affiliation: Department of Orthopedics and Traumatology, Odense University Hospital, Odense, Denmark; Institute of Clinical Research, University of Southern Denmark, Odense, Denmark. Electronic address: ahlarsen@health.sdu.dk.
authors.forename: A
authors.initials: A
authors.lastname: Holsgaard-Larsen
authors.affiliation: School of Exercise Science, Australian Catholic University, Brisbane, Queensland, Australia. Electronic address: mark.creaby@acu.edu.au.
authors.forename: M W
authors.initials: MW
authors.lastname: Creaby
authors.affiliation: Department of Radiology, Odense University Hospital, Odense, Denmark. Electronic address: gittemaria@gmail.com.
authors.forename: G M
authors.initials: GM
authors.lastname: Jørgensen
authors.affiliation: Department of Orthopedics, Lillebaelt Hospital, Kolding, Denmark. Electronic address: nis.nissen@rsyd.dk.
authors.forename: N
authors.initials: N
authors.lastname: Nissen
authors.affiliation: Clinical Epidemiology Unit, Orthopedics, Department of Clinical Sciences Lund, Lund University, Lund, Sweden; Clinical Epidemiology Research and Training Unit, Boston University School of Medicine, Boston, MA, USA. Electronic address: martin.englund@med.lu.se.
authors.forename: M
authors.initials: M
authors.lastname: Englund
authors.affiliation: Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark; Department of Orthopedics and Traumatology, Odense University Hospital, Odense, Denmark; Department of Clinical Sciences Lund, Orthopedics, Lund University, Lund, Sweden. Electronic address: Stefan.lohmander@med.lu.se.
authors.forename: L S
authors.initials: LS
authors.lastname: Lohmander
mesh_terms: D001182:Arthroscopy; D005260:Female; D006801:Humans; D007719:Knee Joint; D008297:Male; D000074403:Meniscectomy; D008592:Menisci, Tibial; D008875:Middle Aged; D020370:Osteoarthritis, Knee; D011446:Prospective Studies
keywords: Arthroscopy; Biomechanics; Joint load; Knee adduction moment; Meniscectomy; Osteoarthritis