Abstract
Objectives
Proximal tibial fracture is one of the most common postoperative complications of unilateral knee arthroplasty (UKA). The objective of the present study is to investigate the risk factors of these fractures, occurred after UKA in our facility.
Method
We performed 314 UKAs between May 2006 and December 2013. All cases were done using Oxford UKA. Proximal tibial fractures were observed in 5 cases. 4 cases were female and 1 case was male, and the age at the operation ranged from 73 to 90. All cases were osteoarthritis. 4 cases were diagnosed as stress fracture with minimum displacement, and 1 case was fracture with displacement. We investigated the risk factors of the tibial fracture among those 5 cases. Low bone mineral density(BMD), the presence of medial tibial cortex pinhole, excessive vertical cut, and adjacence of keel and posterior tibia cortex were estimated as risk factors.
Results
The loss in BMD was seen in all cases. Medial tibial cortex pinhole was recognized in 2 cases. Excessive vertical cut was recognized in 3 cases. Adjacence of keel and posterior tibia bone cortex was recognized in 3 cases, and the distance between keel and posterior tibia bone cortex was less than 3mm in all of these 3 cases. 4 cases those diagnosed as stress fractures, healed spontaneously with conservative treatment, but the case with displaced fragment needed ORIF.
Discussion
Loss in BMD was seen in all cases as predicted, and this is one of the highest risk factors in UKA patient. Preoperative PTH use is recommended when low BMD was seen. Other risk factors are, medial tibial cortex pinhole, excessive vertical cut, and adjacence of keel and posterior tibial cortex. These risk factors are preventable if some cares are taken during the operation. Medial inclination of the tibial plateau should be checked preoperatively to avoid excessive vertical cut. If the distance between keel and posterior tibial cortex is less than 3mm at the preoperative planning, we should consider converting the implant. Furthermore, it is important to pay attention to intraoperative procedures. We should not use heavy hammer and avoid excessive varus force during cementing. For the prevention of tibial fractures after UKA, both strict preoperative planning and prevention of intraoperative errors are important.
