Satisfactory mid-term outcomes of condylar-constrained knee implants in primary total knee arthroplasty: clinical and radiological follow-up

Abstract

Background The purpose of this study was to evaluate (1) the reoperation rates and survivorship for septic and aseptic causes, (2) radiographic outcomes, and (3) clinical outcomes of condylar-constrained knee (CCK) implants used in primary total knee arthroplasty (TKA) with severe coronal deformity and/or intraoperative instability. Materials and methods A consecutive series of CCK implants in primary TKA was retrospectively evaluated in patients with severe coronal deformities. Forty-nine patients (54 knees) were included with a mean follow-up of 9 years (range 6–12). All patients were treated with a single-design, second-generation CCK implant. The primary diagnosis was osteoarthritis in 36 knees, post-traumatic arthritis in 7 knees, and rheumatoid arthritis in 4 knees. Preoperatively, standing femorotibial alignment was varus in 22 knees and valgus in 20 knees. Results At a mean follow-up of 9 years, overall survivorship was 93.6%. Two knees (4.3%) required revision for periprosthetic joint infection. One knee (2.1%) required subsequent arthroscopy due to patellar clunk syndrome. At final follow-up, no evidence of loosening or migration of any implant was reported, and the mean Knee Society knee scores improved from 43 to 86 points (p < 0.001). The mean Knee Society function scores improved to 59 points (p < 0.001). The average flexion contracture improved from 7° preoperatively to 2° postoperatively and the average flexion from 98° to 110°. No knees reported varus–valgus instability in flexion or extension. Conclusion CCK implants in primary TKA with major coronal deformities and/or intraoperative instability provide good midterm survivorship, comparable with less constrained implants. In specific cases, CCK implants can be considered a viable option with good clinical and radiographic outcomes. However, a higher degree of constraint should be used cautiously, leaving the first choice to less constrained implants. Level of evidence Therapeutic study, level IV.

Semiconstrained posterior-stabilized total knee arthroplasty: indications, risks and benefits in primary and revision surgery

“…Most authors recommend using VVC inserts in cases of severe bone loss or ligamentous laxity, with reports of excellent outcomes at 5 years 27 and 7 years 28 without documented aseptic loosening. An overall 9-year survival rate of 93.6% 29 and a 10-year survival rate of 96% 9 with regard to aseptic loosening have been reported with the use of the VVC design. There is no consensus as to how much laxity mandates the use of a VVC inset, but its use when there is persistent intraoperative laxity greater than 7 mm-10 mm has been suggested.…”

Short-Term Survivorship of 3D-Printed Titanium Metaphyseal Cones in Revision Total Knee Arthroplasty: A Systematic Review.

“…33,35 In the case of bone loss reconstruction with 3-D printed or custom-made metal cones, according to this systematic review, a CCK implant was used in 61% of the revisions (301 of 487 knees), followed by RHK in 22% (111 knees), and PS in 13.9% (68 knees). [36][37][38] Despite a relatively high rate of complications associated with metal cones for reconstruction of bone defects in revision TKA, patients showed considerable improvement in a variety of functional scores. Specifically, 3-D printed and custom-made metal cones were associated with an average improvement of 50 points in the KSS between preoperative and latest follow-up.…”

Current Reconstruction Options in Periprosthetic Fractures Around the Knee

“…In case of Lewis and Rorabeck type III fractures, ORIF is not enough, and the loose component should be revised with an implant with a higher level of constraint. 5 , 10 , 23 Implant revision is a valuable option in case of failed fixation, however, bone stock, fracture comminution, and bone quality are crucial elements. 24 Stem extensions are usually required to enhance fixation beyond the fracture line and can be cemented in case of thin cortex and wide medullary canal, or press-fit in case of good bone-quality.…”