- Hipokrat Tıbbi Malzemeler İmalat ve Pazarlama A.Ş.
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Cruciate-Retaining Design
As the name implies, the posterior cruciate ligament is kept with this implant design (the anterior cruciate ligament is removed). Cruciate-retaining implants do not have the center post and cam design. This implant may be appropriate for a patient whose posterior cruciate ligament is healthy enough to continue stabilizing the knee joint.
Minimally constrained prosthesis that depends on an intact PCL to provide stability in flexion
Indications
• Arthritis with minimal bone loss, minimal soft tissue laxity, and an intact PCL
• Varus deformity < 10 degrees – valgus deformity < 15 degrees
Radiographs
Radiographs won’t show box in the central portion of the femoral component as PS knees have
Advantages
• Avoids tibial post-cam impingement/dislocation that may occur in PS knees
• More closely resembles normal knee kinematics
• Less distal femur needs to be cut than in a PS knee
• Improved proprioception with preservation of native PCL
• Newer poly-options can allow for PCL substitution via anterior-stabilized or ultra-congruent shapes in cases of PCL insufficiency without loss of functional results
Disadvantages
• Tight PCL may cause accelerated polyethylene wear
• Loose or ruptured PCL may lead to flexion instability and subluxation
Tasarım
Fleksiyonda stabilite sağlamak için sağlam bir arka çapraz bağa dayanan minimal kısıtlanmış protez
Endikasyonlar
• Minimum kemik kaybı, yumuşak doku gevşekliği ve sağlam bir arka çapraz bağ olan artrit durumu
• Varus deformitesi <10 derece – valgus deformitesi <15 derece
Radyografiler
Bağkesen tipi diz protezlerde olduğu gibi radyografiler femoral bileşenin orta kısmında kutu göstermez
Avantajlar
• Ps dizlerde meydana gelebilecek post-cam sonrası çıkma veya sıkışmayı önler.
• Normal diz kinematiğine daha çok benziyor
• PS dizdekinden daha az kemik kesilmesi gerekir
• Doğal PCL’nin korunmasıyla geliştirilmiş propriyosepsiyon
• PCL yetersizliği durumlarında fonksiyonlarda kayıp olmaksızın anterior stabilize veya ultra uyumlu şekiller yoluyla PCL ikamesine izin verebilir.
Dezavantajlar
• Sıkı PCL, polietilenin hızlı bir şekilde aşınmasına neden olabilir.
• Gevşek veya yırtılmış PCL fleksiyon dengesizliğine ve subluksasyona neden olabilir
Tasarım
• Slightly more constrained prosthesis that requires sacrifice of PCL
• Resection of PCL increases the flexion gap in relationship to extension gap so posterior must be matched to avoid flexion-extension mismatch
• Femoral component contains a cam that engages the tibial polyethylene post during flexion
• Polyethylene inserts are more congruent, or deeply “dished”
Endikasyonlar
• Previous patellectomy
• Reduces risk of potential anteroposterior instability in setting of a weak extensor mechanism
• Inflammatory arthritis
• Inflammatory arthritis may lead to late PCL rupture
• Deficient or absent PCL
Radyografiler
Lateral radiograph will show the outline of the cam, or box, in the femoral component
Avantajlar
• Easier to balance a knee with absent PCL
• Arguably more range of motion
• Easier surgical exposure
Dezavantajlar
• Cam jump mechanism with loose flexion gap, or in hyperextension, the cam can rotate over the post and dislocate treatment initial closed reduction by performing an anterior drawer maneuver final revision to address loose flexion gap
• Tibial post polyethylene wear
• Patellar “clunk” syndrome mechanism scar tissue gets caught in box as knee moves into extension treatment arthroscopic versus open resection of scar tissue
• Additional bone is cut from distal femur to balance extension gap