Knee pain particularly anterior knee pain has been documented as a common complication. It is common following tibia intramedullary nailing and retrograde femoral nailing. It also occurs in antegrade femoral nailing.
Nailing refers to the presence of an rod inside the canal of a long bone.
In this article, we will explore a few of the reasons behind knee pain after rod placement, in either a thigh bone or shin bone.
Incidence
The incidence of anterior (front) knee pain following intramedullary rod insertion is over 86%. This study found an incidence of 30% following intramedullary nail placement for tibia fractures.
Causes.
Beware that the exact cause of the knee pain is not known, but there are a myriad of reasons why this could happen.
The causes do vary depending on the surgical approach and location of the nail. We can’t only attribute it to these since this pain is usually multifactorial.
Antegrade nailing
- Lower most locking screws impinging on the soft tissues around the knee joint
Retrograde femur nailing
- Protrusion of the distal(lower most) locking screws
- Impingement of the nail on the patella tendon which connects the quadriceps muscles to the shin bone.
- Impingement of the nail on the joint surface of the upper part of the tibia (tibia plateau)
Tibia nailing
- Longitudinal split through the patella tendon for nail insertion
- Upward protrusion of the nail. This implant can irritate the patella tendon and the fat pad located in the knee joint.
- Violation of the proximal tibiofibular joint by a locking screw.
- Injury to the infrapatellar nerve, a branch of the saphenous nerve which runs parallel to the patella tendon
Other causes;
- The pain can also be secondary to pathologies around the knee that can’t be seen on x-ray or cant be visualized during surgery .
These are injuries to the ligaments around the knee, other injuries to the bone and to the cartilage of the knee joint that occur concomitantly during the accident.
Presentation and impact of the knee pain
- Pain at the knee is the most common complaint; predominantly the front of the knee.
- Inability to straighten out the leg, which is medically called loss of extension at the knee meaning
- Difficulty in kneeling due to pain.
Treatment for anterior knee pain
Seeing that the causes are multifactorial, it is important to clearly confirm the cause before any intervention is planned. These are some of the solutions that can be implemented.
- Observation and Painkillers.
The first line of management after a thorough assessment is observation together with the use of painkillers and sometimes they completely resolve.
- Implant removal
This has been noted to provide relief in some individuals from complete resolution to partial resolution of symptoms. It however is best done after there is radiological evidence of complete bone healing.
Surgeons are recommended to do this to reduce the chances of the patients complaining of knee pain
- Skin incisions about the knee should be placed in areas that are away from kneeling sites. This is especially important in individuals with a culture of kneeling.
- Always endeavor to countersink the nail to avoid protrusion.
- If it can be avoided, it would be best to minimize injury to the patella tendon, fat pad gliding tissues.
- In addition, use of tissue protectors during surgery prevents inadvertent injury to the soft tissues.
- Use adequate length screws as long screws can irritate the adjacent soft tissues.
- Preferably use horizontal incisions to reduce the risk of injuring the infrapatellar branch of the saphenous nerve.
In conclusion, anterior knee pain following intramedullary nail surgery is fairly common. Even though the exact cause is not known, it is believed that the entry point of this implant into the bone may have a role to play.
In many cases following observation and use of painkillers, this pain resolves. Other times, the metallic rod may have to be removed.
