Medial opening wedge high tibial osteotomy for medial compartment overload/arthritis in the varus knee: prognostic factors.
BACKGROUND
Medial opening wedge high tibial osteotomy (OWHTO) is a widely accepted procedure for the treatment of medial compartment arthritis of the knee. Compared with closing wedge HTO, however, the outcomes of OWHTO reported in the literature are incomplete.


OBJECTIVE
To identify the positive and negative prognostic factors related to the outcomes of OWHTO through an evaluation of midterm study results and survivorship analysis.


METHODS
Case series; Level of evidence, 4.


METHODS
From January 2001 to December 2009, a total of 141 consecutive OWHTOs were performed in 123 patients. Only patients with symptomatic medial knee overload/arthritis were included. The patients were evaluated preoperatively and at every follow-up visit with (1) the Knee Society score, (2) the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, (3) another self-evaluation scale, (4) long-leg radiographs, and (5) plain radiographs. Preoperative, intraoperative, and postoperative variables were investigated to find an association with the outcomes.


RESULTS
Of the 123 patients, 15 were lost to follow-up, and 24 were excluded from the study, leaving 84 patients (99 OWHTOs) for the present study. The mean age of the patients at the time of surgery was 54.5 ± 9.2 years. The mean follow-up was 51.5 ± 23.8 months. The Knee Society and WOMAC scores significantly improved after surgery (P < .001). The variables significantly related to a poor outcome were (1) age >56 years (P = .008) and (2) postoperative knee flexion <120° (P < .001); the variables significantly related to a good outcome were (1) Ahlbäck grade 0 arthritis of the medial compartment (P < .001) and (2) excellent preoperative Knee Society score (P < .001). The Kaplan-Meier analysis showed a survival rate of 98.7% at 5 years and 75.9% at 7.5 years.


CONCLUSIONS
With correct indications, OWHTO is a reliable procedure for medial knee arthritis/overload. The outcomes reported are similar to those from other studies, although the variables related to outcomes are slightly different.
Davide Edoardo Bonasia, Azienda Ospedaliera Città della Salute e della Scienza, Centro Traumatologico Ortopedico Hospital, University of Torino, Via Lamarmora 26, 10128, Torino, Italy. davidebonasia@virgilio.it.
Davide Edoardo
DE
Bonasia
Federico
F
Dettoni
Gabriele
G
Sito
Davide
D
Blonna
Antongiulio
A
Marmotti
Matteo
M
Bruzzone
Filippo
F
Castoldi
Roberto
R
Rossi
D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000145:classification / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D010027:Osteotomy / Q000379:methods*; D063868:Patient Outcome Assessment; D011183:Postoperative Complications; D011379:Prognosis; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*; D064232:Visual Analog Scale
HTO; OWHTO; arthritis; high tibial osteotomy; knee; opening wedge