Total Knee Joint Replacement Type CMS Primary Implants – Knee

Implant Description Surgical Technique Preface The BEZNOSKA/CMS implant for knee joint replacement was designed primarily on the basis of personal and clinical results and experience with various types of oncological knee joint replacement. The technique facilitates simple and perfect fixation of the implant with the aid of intramedullary stems and may be combined with partial replacement of the femur and tibia. Optimization of the shape of knee joint surfaces ensures maximal mobility, while preserving a good functional stability and minimal risk of polyethylene (PE) wear.The assortment of available...

Use options Anatomic suspension implant with inner rotation. Thanks to the implant’s higher inner stability, it can be conveniently used for customized versions, especially in cases involving major bone loss. The implant is particularly suitable for: P ▪ atients with deformation changes and severe instability of the knee joint ▪ Patients with bone tumors in the knee area or major bone defects due to other causes (requiring implant customization) The implant comprises of the following component: (for details, see pp. 38–45): ▪ Femoral component, type CMS ▪ Tibial component, type CMS ▪ Articulation...

Implant Description Surgical Technique ■ Surgical technique The surgical procedure starts with basic tibial resection. The individual steps during the operation consecutive phases are always the same, even in cases deviating from the recommended sequence of procedures. Subsequent partial steps: ■ preparation of the bone marrow section of the tibia ■ resection of the proximal end of the tibia and preparation thereof for the tibial component ■ cutting the bone marrow section of the femur ■ distal resection of the femur ■ setup of outer rotation of the femoral component ■ femoral resection (ventral,...

Preparation of the tibia 1. Opening the bone marrow canal of the tibia After loosening the soft tissue around the tibia and shifting the tibia forward with the aid of the lifting device, open the bone marrow canal. Drill a hole in the bone marrow canal (T) using a pointed bit, Ø 8 mm 158 , cassette "Common Instruments I" along the axis of the tibia. Determine the position of the canal using ventrodistal x-ray or the hole after a revised tibial component. Drill to a depth of 5 cm, maximum, and finish the preparation process by careful pressing the drill, in still mode, all the way into the canal....

Implant Description Surgical Technique 3. Inserting centering rod Remember the diameter of the last grinder used for grinding the tibia. Now insert the assembled guiding rod that is used for anchoring and positioning of the intramedullary aiming device. The complete set consists of a bushing 173 - 178 of the guiding rod 169 and a head "T" 152 . The size of the bushing must match the size (diameter) of the last grinder used. To facilitate assembly of the set (especially bushing) it is suitable to use a trial bushing for the canal 168 , (see Fig. 4). Once the whole set of guiding rod is inserted,...

5. Preparation of tibial resection The next step involves complementation of the aiming device on the upper resection facet of the resection block with a gauge (0,-3) (J17. Set the point of the gauge (we recommend) on the tibia in the lowest position (see Fig. 7). Rotate the assembly slowly to set it in the right position, so that the axis of the resection block (depending on type of axial deformity) runs through the middle of tuberositas tibiae or slightly off the middle between it and the middle edge of tuberculum laterale of intercondylic eminence. Use the centering rod @) from the Common Instruments...

Implant Description Surgical Technique 6. Tibial resection Release the resection block, add the guiding rod for the saw blade, and cut the tibial facet to the extent necessary. Thereupon take off the guiding rod and the resection block, and extract the pins using the extractor (Fig. 34 , page 16). 186 - 187 Fig. 9: Securing of set - up tibial aming device Fig. 10: Assembly of centering matrix with handle

7. Setting up rotation of tibial component First, assemble the tibial centering matrix 173 - 178 of the selected size (2–5) using the matrix handle 87 (see Fig. 10) Re-insert assembled guiding rod into the bone marrow canal, where it will be used as a centering and anchoring element for the centering matrix. Put the matrix on the guiding rod along with the handle and centering bushing 77 and then over the resection facet, so that the oval part fits into the hole in the matrix. Insert the centering rod from Common Instruments Cassette III 184 through the hole in the handle * and slowly rotate...

Implant Description Surgical Technique 8. Preparation of canal for tibial component Put bushing 80 on the tibial centering matrix, so that the pins on the bottom side of the plate fit into unmarked holes in the matrix. Simultaneously, it is necessary to position the matrix as well as the headed fixation pins (both indentations on the side of the plate are designated for the head of the pin), see Fig. 13. Using a cone-shaped grinder bit 79 , prepare the canal for the stem of the tibial component (keep drilling until the grinder ring * touches the bushing) see Fig. 14. The final shape of the prepared...

Now take off the cone-shaped grinder drilling bushing and replace it with a bushing for drill with a diameter of Ø 23 mm 81 (see Fig. 16). Thereupon use the cylindrical drill 0–23 78 to prepare the canal for the tibial facet jut (see Fig. 17, 18) Finish the shape of the canal with a chisel 167 , by making the sides of the drilled holes (19, 20) perfectly even. Fig. 18: Tibial canal drilled to a diameter of ∅ 23 Fig. 19: Final shape of the canal in the proximal part of the tibia Fig. 17: Preparation of the canal for the tibial facet jut Fig. 20: Make the sides of the drilled holes even with the...

Implant Description Surgical Technique Preparation of the femur 9. Opening the bone marrow canal of the femur The drill for perforating the bone marrow canal (pointed bit) 158 to a diameter of 8 mm from the Common Instruments Cassette I. is driven along the femoral axis just above the upper end of the intercondylic incision, towards the middle or, better yet, more centrally by 5 mm (see Fig. 21). After drilling a hole to a depth of 4–5 cm, press the drill, in still mode, all the way into the canal. This way, the drill will find its position in the canal, diminishing the risk of the corticalis...