Total knee approaches

Total Knee

1. Total knee approaches

2. Medial Parapatellar Approach Room setup and equipment standard OR table Patient positioning supine position bump under the operative hip to minimize hip external rotation if needed (goal is to have patella facing straight up) Thigh tourniquet should be placed as proximal as possible to allow adequate room for prepping and draping (ideally placed in hip crease)

3. Medial Parapatellar Approach Draw incision and identify anatomy identify tibial tubercle , patella , draw a straight midline incision starting several centimeters (generally four finger breadths) proximal to the proximal pole of the patella and continuing just distal to the tibial tubercle

4. Medial Parapatellar Approach Incise to extensor mechanism carry the skin incision straight down to the deep fascia which marks the extensor mechanism (quad tendon, patella, and patellar ligament)

5. Medial Parapatellar Approach Create skin flaps elevate skin flaps just deep to the fascia the perforating arteries which supply the skin run just superficial to the deep fascia

6. Medial Parapatellar Approach Identify medial aspect of patellar tendon and quadriceps tendon identify the medial aspect of the patellar ligament, medial aspect of the patella and the quad tendon lateral to the vastus medialis oblique (VMO).

7. Medial Parapatellar Approach Perform arthrotomy start from the proximal aspect in a longitudinal manner curving medially around the patella, leave 3-5 mm of soft tissue on the patella to assist with arthrotomy closure later in the case complete the arthrotomy by a straight distal cut along the medial border of the patellar ligament

8. Medial Parapatellar Approach Perform proximal tibia soft tissue release sharply dissect enough of the medial capsular sleeve off of the tibia to provide exposure of the joint the amount of dissection is variable, depending on the particular knee, but a good rule of thumb is to dissect the tibia posteriorly to the mid-coronal plane 

9. Flex knee, evert patella, and prepare joint space flex the knee to at least 90 degrees and evert the patella resect fat pad, ACL remnant& meniscus place retractors a lateral retractor is then placed under the lateral meniscus near the mid-coronal plane a medial retractor retracts the medial sleeve posterior retractor (PCL or Hohmann style) is placed in front to the PCL to push the tibia anteriorly

10. Medial Parapatellar Approach Advantages familiar to most excellent exposure even in challenging cases Disadvantages failure of medial capsular repair lateral patellar subluxation access to lateral retinaculum less direct may jeopardize patellar circulation if lateral release is performed

11. Lateral Parapatellar Approach Advantages useful for a fixed valgus deformity preserves blood supply to patella prevents lateral patellar subluxation direct access to lateral side in a valgus knee Disadvantages technically demanding medial eversion of patella is more difficult may require tibial tubercle osteotomy

12. Midvastus 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 Relative contraindications ROM <80 degrees  obese patient hypertrophic arthritis previous HTO

13. Subvastus Approach     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 potential for denervation of VMO Relative contraindications revision TKA large quadriceps previous HTO obese patient previous parapatellar arthrotomy

14. 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

15. Extensile Exposures 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

16. Extensile Exposures 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

17. Summary