RECONSTRUCTION 2023, Jan, 08 | 12:00 am

Cemented Total Knee Arthroplasty

 

P ITFALLS

  • Radicular pain from spinal disease

     

  • Referred pain from the ipsilateral hip

  • Peripheral vascular disease

  • Meniscal pathology

 

Cemented TKA

 

Indications

  • Indications to use cement are vast, and cemented fixation is applicable to all total knee arthroplasties (TKAs).

  • Relieve pain caused by tricompartmental arthritis

  • Correct deformity

  • Restore function

    Examination/Imaging

  • Range of motion

    Treatment Options

    • Unicompartmental arthroplasty

    • Patellofemoral arthroplasty

    • High tibial osteotomy

    • Arthroscopic procedures

     

  • Overall limb alignment

  • Medial-lateral and anterior-posterior stability

  • Anteroposterior (Fig. 1A), lateral (Fig. 1B and 1C), and Merchant’s (sunrise) (Fig. 1D) radiographs

    Positioning

     

    P EARLS

    • A Zimmer metal leg holder boot is fashioned to the foot and ankle with the use of a bandage. The boot is not placed into the leg holder; instead, it can be easily positioned and repositioned during the procedure.

       

      P ITFALLS

    • Obese patients may require larger tourniquet sizes.

     

  • Patient is supine on operating table.

  • Tourniquet is placed around the upper thigh.

  • Foot holder is used, but not attached to table.

    Portals/Exposures

  • Traditional median parapatellar

  • Traditional subvastus

  • Traditional midvastus

  • Minimally invasive alternatives/modifications (Fig. 2)

    Procedure

    Step 1

    Equipment

    • Leg holder of choice

     

  • We use an abbreviated (less-invasive) trivector approach to the knee (see Fig. 2).

  • An incision medial to the tibial tubercle to the superior aspect of the patella is made.

  • The attachment of the vastus medialis is dissected

    Controversies

    • Minimally invasive techniques are now proving to be beneficial to patients.

    • Patient selection continues to be an area of debate.

     

    from the quadriceps tendon, proximally, not to exceed 3 cm above the superior pole of the patella.

  • A medial soft tissue sleeve is carefully elevated back to the posteromedial corner of the knee.

  • A portion of the patellar fat pad is removed.

  • The patella is then slid into the lateral gutter and the knee is flexed.

 

 

 

Cemented TKA

 

A B

 

 

 

205

 

C D

 

 

FIGURE 1

 

 

P EARLS

  • Careful elevation of the medial collateral ligament prevents disruption with forced subluxation of the knee.

     

  • Gradually extending the arthrotomy proximally can allow for improved exposure in more difficult cases.

 

 

 

FIGURE 2

 

 

P EARLS

  • The amount of bone removed should equal the thickness of the prosthesis.

     

    P ITFALLS

  • The position of the femoral starting hole may alter the valgus angle. Preoperative templating of the medullary canal and valgus angle can help ensure proper alignment.

 

Cemented TKA

 

Step 2

  • An intramedullary (IM) guide is used for the femur.

  • A large drill hole is made in the midportion of the intercondylar notch.

  • The IM guide is set at 4° and inserted into the femoral canal. A distal femoral Slidex (Biomet, Inc. Warsaw, IN) cutting block is inserted onto the guide. (Fig. 3A).

  • The block is pinned into place and the distal femur is cut (Fig. 3B).

 

 

206

 

Instrumentation/ Implantation

  • Microplasty instrumentation with Slidex blocks allows excellent visualization of each resection. This way each cut is safe and accurate.

  • We utilize specialized retractors from Innomed, Inc. (Savannah, GA) for minimally invasive TKA (Fig. 4A and 4B).

 

A

 

 

 

FIGURE 3 B

 

 

 

207

 

Cemented TKA

 

A B

FIGURE 4

 

 

P EARLS

  • Proper tensioning of retractors will prevent skin tears, ligamentous injury, or bony injury.

     

  • The tension of the retractors can be adjusted to expose one area of the knee and then the next.

     

  • The tibial resection guide should be placed as far laterally as possible without harming the skin or patellar tendon.

 

Step 3

  • An extramedullary guide is used for the tibial cut.

  • The anterior cruciate ligament is resected from its footprint.

  • The tibia is subluxed forward.

  • The extramedullary guide is placed over the medial third of the tibial tubercle, in line with the tibial crest, and in the center of the ankle joint (Fig. 5).

  • Appropriate slope is determined and the guide is pinned into place (Fig. 6).

  • The collateral ligaments are protected with retractors, and the tibia is cut perpendicular to its axis.

 

 

 

FIGURE 5 FIGURE 6

 

 

P ITFALLS

  • A varus cut of the tibia should be avoided at all costs. Varus tibial resection with any TKA is associated with increased failure, especially in obese patients.

 

Cemented TKA

 

Step 4

  • A posterior referencing system is used to complete the femoral cuts.

  • The correct amount of femoral external rotation is determined based on the posterior condylar axis, the transepicondylar axis, 90° to the tibial axis (resected surface), and the anteroposterior axis (Whiteside’s line) (Fig. 7).

    Instrumentation/ Implantation

    • Microplasty instrumentation (Biomet, Inc.).

     

  • The guide is placed on the distal femur. The femur is sized and the patient-matched size is selected (Fig. 8).

     

     

    Controversies

    • Debate exists over IM versus extramedullary techniques.

     

     

    208

     

    FIGURE 7

     

     

     

     

    FIGURE 8

     

    209

     

     

     

    Cemented TKA

     

    FIGURE 9

    • The Slidex 4-in-1 cutting block is then placed on the distal femur and the cuts are completed utilizing a “mobile window” concept (Fig. 9).

    • Posterior, anterior, and chamfer cut bone is removed.

      Step 5

    • A laminar spreader is then placed on the lateral compartment of the knee (Fig. 10A).

    • The medial meniscus is removed.

    • Posterior osteophytes are removed with a curved osteotome and an angled curette.

    • The laminar spreader is moved to the medial side and débridement of the lateral compartment is performed (Fig. 10B).

       

       

       

      FIGURE 10 A B

       

       

       

      210

       

      Cemented TKA

       

      FIGURE 11

       

      Step 6

  • The tibia is subluxed forward, and the tibia is sized and prepared for a trial baseplate (Fig. 11). We routinely utilize an I-beam tibial component.

  • A trial femoral component is inserted.

  • A trial polyethelene component is then inserted and stability is checked.

    Step 7

  • The trial components are removed and the knee is decompressed. The patella is held in a vertical position with the use of towel clips or a patellar holding device.

  • The patellar thickness is measured with a caliper prior to resection.

  • The average thickness of the female patella is 23 mm and that for a male is 25 mm. The objective is to restore the patella height without overstuffing the patellofemoral joint.

  • The patella is resected with a wide oscillating saw blade, first commencing at the inferior pole of the patella at the insertion of the patellar tendon and cutting to the superior pole at the insertion of the quadriceps tendon, then refining by cutting at 90° across, from medial to lateral (Fig. 12). The patella is sized and holes are cut for a three-peg patellar component. A trial component is placed and the thickness of the construct is measured with a caliper.

     

     

     

    211

     

    Cemented TKA

     

    FIGURE 12

     

    Step 8: Cementing Technique

    • The wound is injected with a combination of ketorolac (Toradol), ropivacaine (Naropin), and epinephrine (Fig. 13).

    • Prior to implant insertion and application of cement, supplemental holes are punched or drilled into the sclerotic areas of the tibia to improve cement adherence (Fig. 14).

       

       

       

       

       

       

      FIGURE 13

       

      FIGURE 14

       

       

      212

       

       

       

      Cemented TKA

       

      FIGURE 15

  • The cut bone surfaces are irrigated with high-pressure lavage (Fig. 15). The goal is to remove all fatty tissue, blood, and necrotic tissue from the interstices of the cut cancellous surfaces.

  • The bone surfaces are then carefully dried with suction and by patting with a surgical sponge (Fig. 16A and 16B).

  • The authors utilize high-viscosity cement (Fig. 17A and 17B).

  • Long-term data in regard to hip replacement have shown improved results and longevity with the use of high-viscosity cement.

 

 

 

FIGURE 16 A B

 

 

 

Cemented TKA

 

A

FIGURE 17

B

 

  • Additionally, commercially available high-viscosity cement is available in a precolored state. The distinct blue or green color is significantly more visible, so excess cement is more easily removed.

  • The authors routinely utilize antibiotic-impregnated cement for primary and revision TKA.

  • High-viscosity, antibiotic-impregnated, precolored cement is spread over the tibia while negative intramedullary pressure is created with suction. Suction is applied to the bony cut surface and any drilled or punched holes in the anterior tibial surface (Fig. 18).

     

     

     

    213

     

    FIGURE 18

     

     

     

    214

     

    Cemented TKA

     

    FIGURE 19

     

    • Cement is placed on the backside of the tibial implant (Fig. 19).

    • The tibial I-beam or keel is fully cemented. Excess cement is removed. High-viscosity, precolored cement is easier to remove from the back of the knee (Fig. 20).

    • The distal femur is coated in a similar manner; however, the posterior femoral condyles are not directly coated (Fig. 21). Again, suction can be applied to any drilled holes in the femur to allow better cement penetration into the femoral bone.

       

       

       

       

      FIGURE 20

       

       

       

      Cemented TKA

       

      FIGURE 21 FIGURE 22

       

      215

       

      • The entire backside of the femoral implant is coated with cement and the implant inserted (Fig. 22).

      • The bony cut surface of the patella is cleaned and dried in a similar fashion.

      • Cement is spread on the patella and applied to the back of the patellar button (Fig. 23).

      • The patella is then cemented in place and held until the cement has cured.

      • Warmed saline solution is poured into the wound to facilitate the cement curing process (Fig. 24).

         

         

         

        FIGURE 23 FIGURE 24

         

        216

         

        Cemented TKA

         

        Step 9

    • With the trial tibial insert removed and traction applied, the leg is extended to expose the posterior recess of the knee, allowing for careful removal of excess posterior cement from behind the tibial baseplate.

    • Both the medial and lateral gutters are examined for retained cement.

    • With the knee in high flexion and the assistant providing support under the thigh, the posterior recess of the knee behind the femoral condyles is examined and any residual cement removed.

    • The final tibial insert is locked into place.

    • The tourniquet is released and patellar tracking is checked.

      Step 10

    • The extensor mechanism is closed with a simple interrupted 1 Vicryl Plus suture.

    • The subcutaneous tissue is closed with 2-0 Vicryl Plus suture.

    • The final skin closure is with 3-0 Monocril suture, and then covered with Dermabond.

      Postoperative Care and Expected Outcomes

    • Because patients have received a short-acting spinal anesthetic with long-acting narcotics, they begin physical therapy and ambulation on the day of surgery.

    • Patients can expect a 24- to 48-hour hospital stay and preferably are discharged to home with outpatient physical therapy.

    • The patients are checked in the office at 6 weeks. They are allowed to progress from a walker to a cane as tolerated.

    • In a recent review of 1292 consecutive primary cemented TKAs done by the senior author (A.V.L.) from 1994 to 1996, cemented TKA achieved an overall implant survivorship of 98.5%. Only seven cases (0.5%) involved aseptic loosening of cemented components.