Resorbability of rigid beta-tricalcium phosphate wedges in open-wedge high tibial osteotomy: a retrospective radiological study.
The open-wedge high tibial osteotomy (OWHTO) is a well accepted treatment modality for patients with osteoarthritis of the medial compartment associated with genu varum. To fill in the osteotomy gap 30% macroporosity rigid beta-tricalcium phosphate (beta-TCP) is frequently used as a stable resorbable bone substitute. However, the resorbability of these beta-TCP wedges is not known. The aim of this study was to investigate this. Twenty-one OWHTO procedures in seventeen patients were performed with the use of 30% macroporosity rigid beta-TCP wedges. The osteotomies were fixed using an angle-stable locking plate. Conventional AP and lateral radiographs were examined in order to assess the resorbability of the 30% macroporosity rigid beta-TCP wedges as a function of time. A radiological classification system consisting of five phases was used to monitor the resorption of the 30% macroporosity rigid beta-TCP wedges. The mean duration of follow-up was 62 months (+/-23 range of 28-99). In all 21 cases, remnants of the 30% macroporosity rigid beta-TCP wedges were still present at maximum follow-up. Although the boundaries between 30% macroporosity rigid beta-TCP wedges and bone remained slightly visible, all osteotomies were completely consolidated and full osseointegration took place. In 16 out of 21 knees the fixation system was removed after a mean duration of 32 months (+/-19 range of 6-62). In six out of 21 knees a conversion to a knee arthroplasty was performed after a mean duration of 56 months (+/-18 range of 37-82). The OWHTO did not interfere with the placement of knee prostheses. Complete resorption of 30% macroporosity rigid beta-TCP wedges did not take place up to 8 years after operation.
Kraal
T
T
Department of Orthopaedic Surgery, VU University Medical Center, Amsterdam, The Netherlands.
Mullender
M
M
de Bruine
J H D
JH
Reinhard
R
R
de Gast
A
A
Kuik
D J
DJ
van Royen
B J
BJ
D000293:Adolescent; D000328:Adult; D019645:Arthroplasty, Replacement, Knee; D001860:Bone Plates; D018786:Bone Substitutes; D002130:Calcium Phosphates; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016348:Osseointegration; D020370:Osteoarthritis, Knee / Q000601:surgery; D010027:Osteotomy; D011183:Postoperative Complications; D011859:Radiography; D012189:Retrospective Studies; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*
D018786:Bone Substitutes; D002130:Calcium Phosphates; C485817:beta-tricalcium phosphate