Influence of low back pain on total knee arthroplasty outcome.
BACKGROUND
Preoperative pain and functional status are strong determinants of postsurgical success in total knee arthroplasty. Patients suffering chronic pain from other coexistent musculoskeletal problems may respond differently postoperatively, with potentially poorer outcomes after surgery. The aim of the study was to determine the influence of low back pain on the outcome of total knee replacement surgery.


METHODS
All patients completed Oxford Knee Scores (OKS), American Knee Society Scores (AKSS) and SF-12 (both physical and mental components). Patients were divided into those with (n=40) and without a documented history of low back pain (n=305).


RESULTS
OKS, AKSS and SF-12 physical scores were significantly worse for patients with low back pain at 24 months following surgery. The mental component of the SF-12 measure demonstrated a significant improvement in median mental health post-operatively for patients with no current history of low back pain. In contrast the group with low back pain showed no improvement in mental health scores post-operatively.


CONCLUSIONS
This study demonstrates that symptomatic low back pain influences functional outcome after total knee arthroplasty surgery and that patients with low back pain show limited or no improvement in mental health post-operatively. Level of evidence II.
Orthopaedic Research Unit, Department of Trauma and Orthopaedics, Gatehouse Building, Glasgow Royal Infirmary, 84 Castle Street, Glasgow G4 0SF, United Kingdom.
J K
JK
Boyle
Orthopaedic Research Unit, Department of Trauma and Orthopaedics, Gatehouse Building, Glasgow Royal Infirmary, 84 Castle Street, Glasgow G4 0SF, United Kingdom.
I C
IC
Anthony
Orthopaedic Research Unit, Department of Trauma and Orthopaedics, Gatehouse Building, Glasgow Royal Infirmary, 84 Castle Street, Glasgow G4 0SF, United Kingdom.
B G
BG
Jones
Orthopaedic Research Unit, Department of Trauma and Orthopaedics, Gatehouse Building, Glasgow Royal Infirmary, 84 Castle Street, Glasgow G4 0SF, United Kingdom.
E F
EF
Wheelwright
Orthopaedic Research Unit, Department of Trauma and Orthopaedics, Gatehouse Building, Glasgow Royal Infirmary, 84 Castle Street, Glasgow G4 0SF, United Kingdom. Electronic address: mark.blyth@ggc.scot.nhs.uk.
M J G
MJ
Blyth
D000368:Aged; D000843:Ankle Joint / Q000503:physiopathology; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D005500:Follow-Up Studies; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D017116:Low Back Pain / Q000150:complications* / Q000523:psychology; D008297:Male; D008603:Mental Health; D020370:Osteoarthritis, Knee / Q000601:surgery; D010329:Patella / Q000601:surgery; D063868:Patient Outcome Assessment; D012086:Reoperation; D012189:Retrospective Studies; D011795:Surveys and Questionnaires
Functional outcome; Low back pain; Total knee arthroplasty