|Preoperative Planning / Special Considerations||check the references|
Synonyms: total knee replacement, TKA, artificial knee, total knee arthroplasty
Applicable ICD-10 codes for knee arthroplasty
- M17.0 - Bilateral primary osteoarthritis of the knee
- M17.10 - Unilateral primary osteoarthritis, knee unspecified
- M17.11 - Unilateral primary arthrosis, right knee
- M17.12 - Unilateral primary arthrosis, left knee
- Z47.33 - Follow-up care after explantation of knee joint prostheses
- Z96.651 - Presence of an artificial joint in the right knee
- Z96.652 - Presence of artificial left knee joint
- Z96.653 - Presence of an artificial knee joint, bilateral
- Z47.33 - Follow-up care after explantation of knee joint prostheses
- knee anatomy
- The medial plateau is larger and concave, the lateral plateau is smaller and convex
- Mechanical axis = the line drawn from the center of the femoral head to the center of the ankle must pass through the center of the knee.
- The epicondylar axis is externally rotated 3 degrees compared to the posterior condylar line
- The distal femoral condyles are at 9 valgus in relation to the anatomical femoral axis
- The tibial plateau is at 3 varus to the tibial axis
- Anatomical axis = line drawn in the middle of the tibia or femur.
- Tibiofemoral angle = angle between the tibial and femoral anatomical axes = 6
- The tibial plateau has a posterior slope of @10
- 3 Kompartimente = medial, lateral, patelofemoral
- Rollback = the posterior movement of the tibiofemoral contact point that occurs when the knee moves from extension to flexion.
- Paradoxical reversal = The tibiofemoral contact point moves anteriorly from extension to flexion with movement of the knee. A paradoxical reversal occurs in total knee replacement with absence of the anterior cruciate ligament and preservation of the posterior cruciate ligament.
- During knee flexion, the tibia rotates inward for the first 20 degrees and then maintains this rotational position until flexion passes 90 degrees as internal rotation increases. (Coughlin KM, J Arthroplasty 2003;18(8):1048-1055).
- Knee pain due to severe arthritis for which non-surgical treatment has failed.
- Artrite patelofemoral grave.
- Ideal PT is thin, old, sedentary, flexion contracture >10, ROM >90.
- Patients with lymphedema, diabetes, and cardiac arrhythmias that require anticoagulation are at increased risk of developing periprosthetic joint infection.
- Knee extensors don't work
- neuropathic joint
- Neuromuscular Dysfunction
- severe vascular disease
- Relative: young, active age, obesity
- Independent predictors of periprosthetic joint infections: highest American Society of Anesthesiologists score, morbid obesity, bilateral arthroplasty, total knee arthroplasty, allogeneic transfusion, postoperative atrial fibrillation, myocardial infarction, urinary tract infection, and prolonged hospital stay. (Pulido L., CORR 2008;466:1710)
- Arthroscopic Debridement - Indicated for patients with 1 year symptoms, NL alignment, mechanical symptoms.
- unicompartmental knee- Indications flexion cont < 15, ROM > 90, age > 60, lack of exercise: easier rehabilitation, costs less, faster ROM, preserves ligaments/proprioception, 92% of last 10 years, 15 years = 60% working. Creates a bone defect that often needs to be filled with allograft
- high tibial osteotomy-for varus deformity <15, young patient, energetic lifestyle, isolated medial arthritis, obese, ROM >90, flexion contracture <15. Requires full weight radiographs. comps=under/overcorrection, AVN, low patella, peroneal nerve injuries, anterior compartment syndrome. Lasts 7-10 years. Contraindicated osteotomy in inflammatory arthropathy.
- Distal femoral osteotomies- for valgus deformity <15, indications as above
- arthodese-Indicated for infections, TKA failure, active young patients, soft tissue defects, absent extensor mechanism, neuropathic joint disease. Fusion in flexion 10-15 and valgus 0-7. Complications = infection, malunion, pain. Success in 80-90% of failed condylar components, 55% of failed joint prostheses.
Preoperative TKA Planning/Special Considerations
- Maximize the patient before surgery. Hgb>12.0, HgbA1C<8, BMI<40, non-smoker, albumin >3.0 g/dl. Consider vitamin D.
- Sufficient muscle relaxation, discuss with anesthesia. Thigh tourniquet with the knee bent to maximize the quadriceps under the tourniquet.
- Incision: usually in the anterior midline of the skin and medial parapatellar capsulotomy. Consider lateral parapatellar for >15 valgus knees.
- Cinnamon:Tibial cut = perpendicular to the mechanical axis of the tibia. The mechanical and anatomical axes of the tibia are generally the same. For PCL receiving TKA backward tilt = 6°-9°. For PCL sacrificing TKA posterior tilt = 0°-3°.
- Hide: Restoration of the original thickness of the patella after surface treatment. Normal patella thickness = 23-25mm. Resection of at least 15mm required to avoid patellar fracture.
- Normal extension range, narrow flexion range: reduce the size of the femoral component or add posterior tipping to the tibial resection; for TKA with preservation of the posterior cruciate ligament, consideration should be given to recession or release of the posterior cruciate ligament to loosen the flexion gap.
- Flexion of the femoral component reduces flexion space.
- Tight extension, tight flexion: Decrease the thickness of the tibial component or further dry the tibia
- A more distal femoral resection only loosens the extension space.
- Femur: Femoral cut angle = Valgus cut angle - typically 5-7° = Angle between the anatomical femoral axis and the mechanical axis = The femoral cut must be perpendicular to the mechanical axis. High valgus cut = 5, short valgus cut = 7
- femurrotation: parallel to the epicondyle axis of the femur. The epicondylar axis is externally rotated 3° to 5° relative to the posterior condylar axis. The AP axis of the femur (Whiteside's line) is perpendicular to the epicondyle axis. Be aware of a hypoplastic lateral femoral condyle causing incorrect internal rotation in the posterior reference of genu valgum.
- Compensation:If the distance is symmetrical, adjust the tibia, if it is asymmetrical, adjust the femur.
- Tourist attractions:The joint line should be 1.5 cm above the top of the fibular head. Also consider measuring the distance from the adductor tubercle to the joint line on the unaffected side for comparison.
- Patellofemoral Joint - Avoid IR Femoral Component (landmarks = A/P femur axis, Epicondylar axis located in slight ER, Posterior condylar axis. Avoid IR tibia. Medialize/Center the Patellar component.
- The polyethylene thickness must be at least 8 mm to keep contact stresses below the yield strength of UHMWPE.
- If a back reference is used between sizes, use a larger size to avoid indentation
- For intermediate sizes with back reference, use the smaller size
- Femoral indentation: Indentation reduces femoral flexion force by 18% and torsional force by 39.2%.(Lesh ML, JBJS 2000;82:1096). However, notching has not been shown to increase fracture risk or alter clinical outcomes.(Ritter MA, JBJS 2005;87:2411).
- Consider cement loaded with low-dose antibiotic (< 2 g of antibiotic per 40 g of cement).(Bourne R., J. Artroplastia 2004;19:69).
- TKA case card.
- Consider a pain relief cocktail injection: narcotic, anti-inflammatory, vasoconstrictor. 30 mg of ketorolac, 5 mg of epimorphine, 0.6 ml of 0.1% epinephrine and 400 mg of ropivacaine in a volume of 100 ml Do not use if filtered blood reinfusion drains are used.
- (1) restoration of mechanical alignment [neutral tibiofemoral alignment = 4°-6° anatomical valgus], (2) horizontal joint line, (3) soft tissue balance (ligaments), (4) patella tracking (Q angle)
- Bilateral TKA: Staged TKA (4-7 days apart from a single hospitalization) has the lowest overall complication rate for patients requiring bilateral TKA compared to sequential TKA and staged TKA. (Sliva CD, JBJS Am 2005;87:508-513)
Considerations for valgus deformity (valgus TKA)
- Loosens osteophytes and capsular band > iliotibial when squeezed in extension; Popliteus is tight in flexion > PCL > LCL: If both flexion and extension are tight, consider releasing the LCL first and gaining other lateral stabilizers. Consider displacement/reconstruction of the medial collateral ligament for severe valgus with medial laxity. Alternative technique for valgus knees = Elkus M, JBJS 2004:86A;2671
- Valgus deformity is usually due to deformity of the distal femur rather than the proximal tibia, as in B. A hypoplastic lateral femoral condyle. When aligning the knee, any deformity of the lateral condyle must be considered to avoid internal rotation of the femoral component, especially when using the posterior condyle line to position the cutting block. (Favorito PJ, Mihalko WM, Krackow KA. Total knee arthroplasty in valgus knee. J Am Acad Orthop Surg. 2002 Jan-Feb;10(1):16-24).
- Knee valgus have: loose MCL, tight lateral reticulum, tight LCL, tight posterolateral corner, atrophic lateral femoral condyle, lateral patellar tracking, tibial ER relative to femur.
Considerations for varus deformity
- Release of osteophytes >Deep MCL >posteromedial angle and fixation of the semimembranosus >elevation of the superficial MCL> ? PCL
- Polyethylene must be direct compression molded without calcium stearate
- irradiation in an inert environment (without air).
- Crystallinity >70% = increased wear. Want 50-56% crystallinity
- You want a short shelf life
- Revision rate of 5.0% for minimally stabilized prostheses compared to 6.0% for posteriorly stabilized prostheses. (Vertullo C., JBJS 2017:99(13):1129-1139)
- posterior sacral containmentDesigns: Benefits = Bone preservation, potentially more physiological femoral reversal, PCL proprioception. Cons = May cause paradoxical anterior femur slip rather than reversal, posterior femoral subluxation if too tight, or flexion instability if too loose, late PCL laxity, less congruent joint surface with potentially increased joint load, severe severe deformities to be corrected.
- PS (PCL replacement: Advantages = firmer recoil, more congruent articular surface. Disadvantages: Patellofemoral Clunck syndrome, infrequent implant dislocation, loss of proprioception, requiring femoral Notch resection.
- Mobile storage:Benefits = ultra-compliant joint geometry with low contact stress, automatic rotation correction. Disadvantages = possible stock change, may be technically more difficult.
- stock materials: metal on metal, alumina/zirconia ceramic, polyethylene.
- Pre-surgery: Review available implants, available instruments, reciprocating saw for cutting cuts, Ortho-Bump for initial exposure, 0.050" oscillating saw
- supine, antibiotic
- Anesthesia: consideration of peripheral nerve blocks (Horlocker TT, JAAOS 2006;14:126)
- Well padded bony prominences
- High thigh tourniquet
- r/l LE prepared and covered in a standard sterile manner
- Limb bled with Esmarch, tourniquet inflated to 300 mmHg
- Midline incision, just above the patella to medial to the tibial tubercle. With a slightly bent knee
- SQ, deep fascia
- artrotomia parapatelar medial
- press release
- slackened lateral patellofemoral ligament
- posterior half of infrapatellar fat pad
- Everted patella and flexed knees
- Macroscopic osteoarthritis in the medial compartment/lateral compartment/patellofemoral compartment
- bone spurs removed
- Proximal Tube
- intramedullary guide
- Drill the hole in line with the tibial axis, usually just lateral to the ACL insertion
- Suction cannula to remove marrow fat
- insert serrated IM guide
- 7 tibial stabilizers 3 or 0 degrees to determine a posterior tibial resection
- clamped in place with the stabilizer and cutting block centered on the medial 1/3 of the tibial tubercle
- The varus/valgus alignment varies with the extramedullary alignment arch and alignment rod. Distal end points toward second toe.
- Define and secure the resection 20 mm from the femoral resection, 2 mm from the inferior side or 10 mm from the superior side
- Removed instant messaging team
- Retractors placed to protect MCL/LCL
- Proximal tibial transverse osteotomy tilted 5 degrees posteriorly
- Meniscus residue removed
- Scale the tibia and check for varus/valgus with the alignment rod
- thigh cuts
- Drill a hole in the center of the patellar groove of the distal femur with a step drill
- aspirated channel
- IM guide adjusted to 5-7 degrees of valgus, fixed with standard cutting block and placed in the IM hole
- Handles positioned relative to the epicondylar axis (lateral epicondyle = origin of the LCL, medial = center of the broad origin of the MCL)
- attached and fixed distal femoral cutting guide
- Removed instant messaging team
- A/P Size Rotation Guide (if smaller between sizes) insert headless pins
- 4 in 1 cutting block placed and check for previous notches, fixed
- posterior condyle cut
- rear bezel
- anterior condyle
- bisel frontal
- Scored Reference Marks for Box Section, Drilled Femoral Screws
- Place and secure the notch guide, make notch with saw and osteotome. For Zimmer box cutting, mark the saw blade at 30 mm, which is the depth of the box.
- Measure the patella (25-30mm)
- Patella buds are typically 10mm thick
- Perform cut Restore patella height with button
- measure size
- light medial placement
- Drill the patella holes with the drilling template
- Consider pain cocktail injection: bupivicaine 80 mg, methylprednisolone 40 mg, morphine 4 mg, epinephrine 300 mcg, cefuroxime 750 mg diluted in 30 mL normal saline (Ranawat CS) and multimodal pain management(Peters CL, J Artroplastia 2006;21 Supl 2:132).
- Tod: 0,53%
- Periprosthetic infection: 0.71%
- Pulmonary embolism: 0.41%
- Patella fracture:
- component loosening:
- Shin splint wear:
- Fibular palsy: 0.3% to 2%
- Periprothetische Femurfraktur:
- Periprothetische Tibiafraktur:
- Complications/wound scabs: rare
- Patellar snap syndrome: rare
- Patellofemoral instability: 0.5%-29%
- Popliteal artery lesion: 0.05%. The popliteal artery is usually posterolateral to the PCL. (Ninomiya JT, Dean JC, Goldberg VM. Popliteal artery injury and its anatomical location in total knee arthroplasty. J Arthroplasty. 1999 Oct;14(7):803-9.)
- Quadriceps tendon rupture: 0.1%
- Patellar tendon rupture: <2%
- rigidityafter total knee arthroplasty: First, a deep infection must be ruled out. Other causes of TKA stiffness include patellar crowding, component misalignment, ligament imbalance, genetic predisposition, aggressive arthrofibrosis. The TKA review score for stiffness is low if no reason for the stiffness is found. (Kim J, Bone Joint Surg Am 2004;86-A(7):1479-1484.)
- fat embolism
- Medial collateral ligament tear
- Vascular injury: postoperative asymmetric absent pulse: consider vascular surgery See intraoperative arteriography; Stent vs surgical repair.
- 10-14 days: wound check, staple removal.
- 6 weeks: Review x-rays.
- 3 months: Check progress with PT.
- 6 months: review of radiographs, assessment of progress.
- 1 year: X-ray inspection for signs of loosening/wear.
- 2 years: X-rays checked for signs of loosening/wear.
- 5 years: Check x-rays for signs of loosening/wear.
- 10 years: check x-rays for signs of loosening/wear.
- Driving: allowed to drive at 6 weeks. (Pierson JL, Arthroplasty J 2003;18:840).
- AAOS urologic procedures in patients referred for THA.
- AAOS antibiotic prophylaxis for dental procedures.
- AAOS post-arthroplasty antibiotic prophylaxis recommendations for elective surgery.
TKA Postoperative Tag 1
- TVT-Prophylaxis: Lovenox 40 mg s.c. once daily (starting 12 [±3] hours before surgery) or 30 mg every 12 hours s.c. (starting 12 to 24 hours after surgery)
- Shut off drain if output <30cc/8hrs
- Check I's & O's and Possibly Hep Lock IV
- Hire Foley ASAP. Discontinue prophylactic Bactrim as soon as the sounds cease
- Make sure the SCDs are turned on and working.
- Patient Enusre has an incentive spirometer and knows how to use it.
- Anemia: Ferrous sulfate or transfusion as indicated.
- Start with 0-30 CPM and increase to 0-90 in 10 degree increments as tolerated.
- Order: 3-in-1 Bedside Table Cammode, Raised Toilet Seat and Walker.
- Survival rate: 90% at 10 years, 80% at 15 years, 75% at 20 years. (Fromson MI, OKU-8). The survival rate is reduced by: obesity, young age, male sex, misaligned prostheses, JRA, hemophilia, osteonecrosis, patellofemoral arthritis.
- 90-95% satisfactory result
- 2% Revision, < 2% Infection.
- knee outcome measurements.
TKA review references
- Lotke PA, Master in Orthopedic Surgery Techniques: Knee Arthroplasty, 2. Aufl., 2002°