- Medial parapatellar approach
Usage of medial parapatellar approach
This approach is used for medial femoral condylar fractures. In addition, it may be used in retrograde nailing of intra articular fractures.
Antibiotics are administered according to local antibiotic policy and specific patient requirements.
Many surgeons use gram-positive prophylactic antibiotic cover for closed fractures, adding gram-negative prophylactic cover for open fractures. Always remember that antibiotic therapy will never compensate for poor surgical technique.
The saphenous nerve runs along the medial aspect of the distal femur. The infrapatellar branches of the saphenous nerve lie on the medial and inferior aspects of the patella. Postoperatively, there may be minor sensory disturbance around and below the scar, but significant saphenous nerve damage is avoidable. Occasionally, there may be postsurgical saphenous nerve neuroma formation which is rarely a significant problem.
The long saphenous vein should be preserved.
There are no surgically important arteries on the medial side of the knee joint.
Tourniquets can be helpful to minimize blood loss and to improve the view of the articular surface. In the trauma patient, the surgeon must consider the effects of ischemia / reperfusion and the potential effects of tourniquet use in the presence of a compromised soft-tissue envelope.
Consideration of tourniquet use should be part of the preoperative planning process. A tourniquet may, or may not, be used depending on the morphology of the fracture and soft-tissue injury. If the fracture margins approach the vicinity of the tourniquet site, a tourniquet is not used.
The surgeon has to take into account that the inflated tourniquet can complicate the reduction of the fracture by fixing the quadriceps in a shortened position. To avoid this, the knee should be carefully flexed beyond 90° with gentle traction applied and the patella manually pushed distally, in order to gain as much length as possible before the tourniquet is inflated. In some cases it may be helpful to deflate the tourniquet while reducing the fracture.
A thigh tourniquet should be not left on longer than 120 min., and for a shorter time in older patients or those with known vascular disease.
The landmarks are the patella, the patellar tendon and the tibial tubercle, which are easily palpable.
Make a longitudinal, slightly oblique, medial parapatellar incision along a line starting 5 cm above the superior pole of the patella to the tibial tubercle.
Flaps should not be raised so as to avoid damage to skin blood supply.
Opening of the knee joint
Incise the medial patellar retinaculum and open the joint capsule.
Proximal and distal extensions
Depending on the fracture configuration, the incision can be extended proximally to increase the exposure of the distal femur.
The incision can be extended more distally towards the tibial tubercle to increase the exposure of the knee joint.
Reflection of the patella and extensor retinaculum
The patella can be dislocated laterally. Be careful to avoid avulsion of the patellar ligament from the tibial tubercle. To aid exposure of the whole distal femur the incision can be extended proximally into the quadriceps tendon.
A retractor can be used gently to hold the extensor retinaculum laterally.
Once the patella is dislocated, there will be a wide exposure of the knee to aid anatomical articular surface reconstruction.
Before closure, irrigate wounds copiously with warm Ringer lactate solution. Close the joint capsule and the fascia with absorbable sutures. The use of a suction drain may be considered. Close the skin meticulously with nonabsorbable sutures.