Open reduction and internal fixation of compound fractures around the knee in elderly patients with osteoporosis have resulted in poor outcomes due to prolonged postoperative immobilization. Arthroplasty is commonly used to treat acute fractures of the proximal humerus, elbow, or proximal femur [
A 90-year-old woman with a body mass index (BMI) of 22.1 kg/m2 visited our hospital with complaints of right knee pain after a fall at home that made it difficult for her to walk. In the emergency department, the patient exhibited swelling of the right knee and tenderness over the distal femur. Plain radiographs of the right knee showed a fracture of distal femur with lateral knee osteoarthritis (Figure
A 90-year-old female with a fracture of the distal femur with lateral knee osteoarthritis. (a) AP view, (b) lateral view, and (c) axial view.
Two dimensional computed tomography (2DCT) scan demonstrating a fracture line from the trochlea to the femoral groove (AO Foundation/Orthopedic Trauma Association classification: type B2) (white and black arrow). (a) Coronal view, (b) sagittal view, and (c) axial view.
TKA was performed with the medial subvastus approach. A robotic-assisted system was used in the image-free handheld RA surgery with the Blue Belt Navio surgical system (Navio; Smith & Nephew, Plymouth, MN, USA) [
A fracture line was observed from the trochlea to the intercondylar notch. The fracture site coincided with the entry point for the intramedullary rod at the time of the conventional TKA. Temporary fixation with two bury pin threads (4.0 mm) was initially used to fix the fracture line (Figure
The fracture line (white arrow) is fixed using two bury pin threads (4.0 mm) and anatomy of the femoral condyle were mapped by “painting” the surfaces with an optical probe. The surface was coated with an optical probe, but it was reduced and there was no separation of the fracture. (a) Intraoperative photograph and (b) image free registration.
Patient-specific planning. (a) A varus/valgus stress test was performed with a manual max through a full range of motion. (b) The medial gap was enlarged with flexion, and mild lateral contracture was observed. Due to reduction as much medial looseness from extension to flexion and lateral contracture from extension to midflexion, femoral and tibial components were performed in valgus alignment and we fine-tuned the amount of osteotomy. (c) Medial and lateral gaps became constant.
The arthritic cartilage and bone were then methodically removed using the handheld sculptor while holding the medial and lateral condyles of the femur, to prevent the fracture site from separating (Figure
(a) Intraoperative photograph. (b) Navio screen allowing the surgeon to continually assess the patient anatomy against the plan. The articular cartilage and bone being removed using a hand-held sculptor. Green: approximately 1 mm or more and less than from target surface; white: near the target surface (less than 1 mm); red: below the target surface. (c) After immobilizing the fracture site with a bone grasper before removing the pin tracker, reaming of the femur and insertion of a stem prosthesis were performed.
Postoperative radiographs showing total knee arthroplasty using the semiconstrained lesion prosthesis (Smith & Nephew). (a) AP view, (b) lateral view, and (c) axial view.
On the two days after TKA surgery, the drainage tube was removed and physical therapy was initiated. A physical therapist started isometric strength exercises for the quadriceps and ROM exercises for the knee joint. Full weight-bearing was not restricted, and the patient was allowed to walk with or without assistive devices.
Prosthetic alignment, Knee Society Scores, and range of motion were assessed at 12 months after surgery (Table
Pre- and postoperative clinical data (90-year-old female, fracture).
Preoperative | Postoperative | ||
---|---|---|---|
Pain (50) | 0 | 96.4 | |
Knee (97) | 0 | 89.7 | |
Function (100) | -20 | 2.1 | |
90 | |||
Femoral tibial angle (°) | 175 | ||
Symptom (25) | 18 | ||
Patient satisfaction (40) | 30 | ||
Patient expectation (15) | 13 | ||
Activity (100) | 71 | ||
Extension angle (°) | 5 | ||
Flexion angle (°) | 120 |
We performed a primary RA TKA for a fracture of the medial condyle of the distal femur with lateral knee osteoarthritis. There are several advantages to this technique. First, two bury pin threads allowed us to fix the fracture site in place and easily burring the distal femur. Second, by using the Navio system, varus or valgus stress is applied to tension the soft tissues on the sides of the knee through a full range of flexion to plan the desired soft tissue laxity. This helps the surgeon plan for implant positioning and volume bone resections, taking into account “virtual” soft tissue laxity prior to making any cuts [
Krachow et al. [
A case report has advantages. First, regarding the rationale for the use of robots in this case, the fracture was nondisplaced, and while a traditional cutting block could have been used, with the help of a large reduction clamp and/or wire, there were advantages to using robotic milling performed with minimal applied force to the distal femoral cartilage surface without inserting an intramedullary rod by fixing the fracture with a tracker pin. Second, RA TKA is a viable option for intra-articular fractures in elderly patients with advanced knee osteoarthritis. Third, physical therapy, which was initiated immediately postoperatively, included full weight-bearing without restriction. Fourth, RA TKA achieves good clinical outcomes at 1 year postoperatively despite advanced age.
A case study has disadvantages. First, we pulled out the 4.0 mm bury pin threads to insert the prosthesis with the stem. Consequently, we have not been able to verify intraoperative kinematics. Second, Renawat et al. [
The unique aspect of the case is that the technique utilized involved robotic milling using the Navio system while temporarily stabilizing the fracture using the tracking pin.
In conclusion, primary RA TKA is a viable option for intra-articular fractures in elderly patients with advanced knee osteoarthritis.
There are no available data.
All authors declare that they have no conflicts of interest.