One component of conventional total knee arthroplasty is removal of the anterior cruciate ligament, and the knee after total knee arthroplasty has been said to be a knee with anterior cruciate ligament dysfunction. Bicruciate stabilized total knee arthroplasty is believed to reproduce anterior cruciate ligament function in the implant and provide anterior stability. Conventional total knee arthroplasty was performed on the right knee and bicruciate stabilized total knee arthroplasty was performed on the left knee in the same patient, and a triaxial accelerometer was fitted to both knees after surgery. Gait analysis was then performed and is reported here. The subject was a 78-year-old woman who underwent conventional total knee arthroplasty on her right knee and bicruciate stabilized total knee arthroplasty on her left knee. On the femoral side with bicruciate stabilized total knee arthroplasty, compared to conventional total knee arthroplasty, there was little acceleration in the
Conventional total knee arthroplasty (TKA) can include preservation of the posterior cruciate ligament (PCL) (cruciate-retaining, CR), removal of the PCL (posterior stabilized, PS), and substitution of the PCL (cruciate-substituting or cruciate-sacrificing, CS), but the anterior cruciate ligament (ACL) is still removed, and the knee after TKA has ACL dysfunction. Therefore, there are cases that experience paradoxical motion, in which the femur exhibits anterior slipping in early flexion; this is considered one of the causes of poor results after TKA [
Victor and Bellemans developed bicruciate stabilized (BCS) TKA to solve this problem [
Conventional TKA on the right knee and BCS TKA on the left knee were performed in the same patient. A triaxial accelerometer was then fitted to both knees after surgery, and gait analysis was performed.
A 78-year-old woman had experienced pain in both knees since around 2005. Conservative medical treatment at a nearby clinic failed to mitigate her symptoms, and she was referred to our hospital in 2012. Preoperative range of motion was −10° and 130° in right knee extension and flexion, respectively, and −5° and 130° in left knee extension and flexion, respectively. The preoperative X-ray showed equivalent deformation on the left and right (Figure
Preoperative X-ray.
Right anteroposterior
Left anteroposterior
Right lateral
Left lateral
In 2012, she underwent right TKA, for which the implant was the Scorpio NRG (Stryker, Mahwah, NJ, USA). It was performed with a medial parapatellar incision, followed by PS and cement fixation, without patellar resurfacing. In 2015, she underwent left TKA, for which the implant was the Journey II (Smith and Nephew, Memphis, TN, USA). That procedure was also performed with a medial parapatellar incision, followed by BCS, cement fixation, and patellar resurfacing.
Postoperative lateral X-ray images of the extended position showed that the posterior offset ratio (POR) was 12.1% with conventional TKA and 0% with BCS TKA. This POR is the POR (
Postoperative X-ray.
Right anteroposterior
Left anteroposterior
Right lateral
Left lateral
The range of motion of the knee joint was 5° to 130° for the right knee and 0° to 145° for the left knee at three months after the BCS TKA. The new Knee Society Score (2011 KSS) was used for postoperative assessment, yielding equivalent results for the left and right knees (Table
New knee society score.
Right conventional | Left bicruciate stabilized | |
---|---|---|
Indicators | 63 | 66 |
Symptoms | 25 | 25 |
Satisfaction | 36 | 36 |
Expectations | 8 | 10 |
Activities | 50 | 48 |
After surgery, the patient was asked to walk with a triaxial accelerometer (Hitachi H48C 3-Axis Accelerometer Module, Hitachi Metals Co., Ltd., Tokyo, Japan) (Figure
Sensors.
Accelerometer
Heel sensor
The resulting data were collected into a data logger (Memory HiLogger LR8431, Hioki E. E. Co., Nagano, Japan). A graph of the actual walking data is presented (Figure
Data of sensors and a definition of the axis.
Data of accelerometer and heel sensor
A definition of the axis of acceleration
Results from walking while wearing the accelerometers on the femur and tibia of the conventional TKA and BCS TKA legs showed a difference in the
Acceleration of the femur.
Conventional femur
Bicruciate stabilized femur
Acceleration of the tibia.
Conventional tibia
Bicruciate stabilized tibia
Acceleration of the conventional and bicruciate stabilized total knee arthroplasty.
BCS TKA has been said to provide anterior stability, but few reports have quantitatively assessed stability. In this report, accelerometers were used to quantitatively assess anterior stability with left/right comparisons made between conventional TKA and BCS TKA in the same patient.
There have been some reports on motion analysis of the knee using accelerometers, and they are reportedly effective tools for motion analysis [
Staab et al. used accelerometers and gyroscopes to conduct gait analysis in OA patients and reported that these sensors were approximately the same as the Vicon [
The ACL is said to act as a stabilizer in the early flexion phase [
BCS TKA may be able to replace ACL function due to the structure of the implant and proper anteroposterior positioning.
The authors state that the patient has given their informed consent for the case report to be published.
The authors declare that they have no competing interests.