Abstract
Introduction
We report a case which total knee arthroplasty (TKA) was able to be performed on schedule for the patient with occult fracture of proximal tibia which seemed to have occurred three months prior to the surgery, and has healed in short period of time by the use of Teriparatide.
Case report
The patient is 84-year-old female, having right knee pain for past 7 years. Her knee pain increased by passive extension maneuver that was done by a bonesetter 3 months prior to the surgery. On her initial visit, the X-ray finding was severe medial osteoarthritis, and femorotibial angle (FTA) in the upright film was 197°, but there was no other disorder including fracture. Since the bone mineral density (BMD) of affected femoral neck was 62%YAM, and affected lateral femoral condyle as well as lateral tibial condyle seemed very porotic, we started using daily 20μg Teriparatide injection from 3 months prior to the surgery. Proximal tibial fracture was presented in the X-ray taken on the day before surgery, but since adequate bone union has already been formed, surgery was performed on schedule. Tibial implant with long stem was used for just to be certain. Thanks to the Teriparatide, the condition of cancellous bone in cut surface was excellent, and reaming of the tibia through fracture area felt very solid.
Discussion
Proximal tibial fracture that occurred just before TKA is very rare. The fracture in this case was probably due to the maneuver done by the bonesetter. Teriparatide is indicated when osteoporosis is severe and the patient is at risk for fracture. We also indicate Teriparatide for the patients whose femoral neck BMD is very low and severe valgus knee or varus knee is present. Unloaded side of femoral or tibial condyle is usually very porotic in such a case. In our case, the fracture was so called fragility fracture which was found incidentally the day before surgery, but TKA could be done on schedule since adequate callus has been formed by the use of Teriparatide which started 3 months prior to the surgery.
