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Updated: Jul 31 2024

TKA Approaches

Images
https://upload.orthobullets.com/topic/5031/images/knee_original-1..jpg
https://upload.orthobullets.com/topic/5031/images/medial_parapatellar.jpg
https://upload.orthobullets.com/topic/5031/images/midvastus.jpg
https://upload.orthobullets.com/topic/5031/images/subvastus.jpg
  • Introduction
    • Surgical approach may be dictated by
      • surgeon preference
      • prior incisions
      • degree of deformity
      • patella baja
      • patient obesity
    • Incision planning
      • if multiple incision, choose more lateral
        • blood supply comes from medial side
      • generally safe to cross previous transverse incisions at right angles
      • ensure adequate skin bridge
        • exact length of skin bridge needed is controversial
    • Approaches
      • "simple" primary knee arthroplasty approaches
        • medial parapatellar
        • midvastus
        • subvastus
        • minimally invasive
      • No midterm or longterm differences have been shown in terms of functional outcomes between a standard medial parapatellar, midvastus, or subvastus approach
      • "complex" primary or revision total knee arthroplasty
        • medial parapatellar
        • quadriceps snip
        • V-Y turndown
        • tibial tubercle osteotomy
  • Standard Medial Parapatellar Approach
    • Overview
      • most commonly completed through a straight midline incision
    • Advantages
      • familiar for most orthopaedic surgeons
      • excellent exposure even in challenging cases
    • Disadvantages
      • possible failure of medial capsular repair
      • development of lateral patellar subluxation
      • access to lateral retinaculum less direct
      • may jeopardize patellar circulation if lateral release is performed
  • Lateral Parapatellar Approach
    • Overview
      • useful for addressing lateral contractures but difficult eversion of patella makes exposure challenging
    • Advantages
      • useful for a fixed valgus deformity
      • preserves blood supply to patella
      • prevents lateral patellar subluxation
      • allows direct access to lateral side in a valgus knee
    • Disadvantages
      • technically demanding
        • medial eversion of patella is more difficult
      • may require tibial tubercle osteotomy
  • Midvastus
    • Overview
      • similar approach to medial parapatellar that spares VMO insertion and may lead to quicker recovery
    • Advantages
      • vastus medialis insertion on quad tendon is not disrupted
      • potentially allows accelerated rehab due to avoiding disruption of extensor mechanism
      • patellar tracking may be improved compared to medial parapatellar approach
    • Disadvantages
      • less extensile
      • exposure difficult in obese patients
      • exposure difficult with flexion contractures
      • potential for partial VMO denervation
    • Relative contraindications
      • ROM <80 degrees
      • obese patient
      • hypertrophic arthritis
      • previous HTO
  • Subvastus Approach
    • Overview
      • muscle belly of vastus medialis is lifted off intermuscular septum
    • Advantages
      • patellar vascularity preserved
      • extensor mechanism remains intact
      • minimal need for lateral retinacular release
    • Disadvantages
      • least extensile
    • Relative contraindications
      • revision TKA
      • large quadriceps
      • previous HTO
      • obese patient
      • previous parapatellar arthrotomy
  • Minimally Invasive Surgical Approach
    • Overview
      • often need special instruments for exposure and implant insertion
      • technically demanding
    • Outcomes
      • data shows no clinically significant improvement in patient reported outcomes, gait patterns or quadriceps strength
      • quadriceps-sparing approach may lead to high rates of component malposition
    • Indications to convert to a standard parapatellar approach
      • patellar tendon starts to peel off the tibial tubercle
      • incision is too small for proper jig placement
  • Extensile Exposures
    • Quadriceps snip
      • technique
        • snip made at apex of quadriceps tendon obliquely across tendon at a 45-degree angle into vastus lateralis
      • advantages
        • no change in post-operative protocol
        • minimal, if any, long-term consequences
      • disadvantages
        • not as extensile as a turndown or tibial tubercle osteotomy
    • V-Y turndown
      • technique
        • straight medial parapatellar arthrotomy with diverging incision down the vastus lateralis tendon towards lateral retinaculum
      • advantages
        • allows excellent exposure
        • allows lengthening of quadriceps tendon
        • preserves patellar tendon and tibial tubercle
      • disadvantages
        • extensor lag
        • may affect quadriceps strength
        • knee needs to be immobilized post-operatively
    • Tibial tubercle osteotomy
      • technique
        • 6-10 cm bone fragment cut from medial to lateral
        • fixed with screws or wires
      • advantages
        • excellent exposure
        • avoids extensor lag seen with V-Y turndown
        • avoids quadriceps weakness
      • disadvantages
        • some surgeons immobilize or limit weight-bearing post-operatively
        • tibial tubercle avulsion fracture
        • non-union
        • wound healing problems
  • Bilateral Total Knee Arthroplasty
    • Definitions
      • simultaneous
        • two surgeons performing the bilateral TKA at the same time
      • sequential
        • one surgeon performing one TKA and then the contralateral TKA under one anesthetic
      • stage
        • done surgeon performing each TKA under a separate anesthetic
        • timing ranges from 3 days to one year in between each side
  • Other
    • Antibiotic loaded bone cement (ALBC)
      • reduces deep infection in revision TKA
      • indications for use in primary TKA are controversial
        • in vitro studies have shown a theoretical risk of decreased cement strength with adding antibiotics (dilution) 
          • however, there are no current studies that have shown ALBC to increase the rate of aseptic loosening
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