Lateral Knee Pain

Diagnosis

 

It seems to me that if I am to come up with a diagnosis for my lateral knee pain then it must cover ALL issues that I have had, and am still encountering, no matter how trivial they might seem. So here goes...

 

After having had an arthroscopic debridement of a radial tear to the lateral meniscus, my symptoms still remain. However research suggests that there might also be other injuries that mimick symptoms of a tear to the lateral meniscus:

 

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445190/

(2011)

Extra-articular Mimickers of Lateral Meniscal Tears

 

Of these injuries, dislocation the proximal tibiofibular joint (PTFJ) appears to be the prime suspect. This may also explain subluxation of tendons and nerves, and also implicate the ankle in the injury (or vice versa).

 

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2397423/

(2008)

Dislocation of the fibular head in an unusual sports injury: a case report

 

The mechanism of the anterolateral dislocation is inversion and plantar flexion of the ankle that causes tension in the peroneal muscles, extensor digitorum longus and extensor hallucis longus and thus applies a forward dislocating force on the proximal fibula. Flexion of the knee relaxes the biceps tendon and the fibular collateral ligament. Twisting of the body at this point is transmitted along the femur to the tibia, which causes an external rotatory torque of the tibia. Rotatory torque of the tibia along with relaxation of the biceps tendon and collateral ligament causes the fibula to displace laterally while the tensed muscles pull it anteriorly.

 

This describes my injury precisely

 

I think that there is an anterolateral dislocation of the proximal tibiofibular joint (PTFJ) of my right knee.

 

http://www.sportsinjurybulletin.com/archive/tibiofibular-joint-damage#

(On website)

Tibiofibular joint damage

It occurs as a result of a complex interplay of sudden abnormal movements in the muscles controlling the ankle and knee, typically following a sudden inversion and plantar flexion of the foot, together with simultaneous knee flexion and twisting ofthe body.

 

I suggest that this is what instigated my injury. I was jogging, and I guess that my foot twisted inwardly on an uneven surface of the path.

 

But something must have happened to put my foot into plantar flexion? I wonder whether the PTFJ was damaged before I twisted my ankle, or maybe I twisted my ankle twice... the second time leaving the peroneal nerve in a different position over the fibular head, thereby producing a foot drop and causing the PTFJ to dislocate. 

 

And here is the link between my lateral knee pain and my ankle:

http://www.ajronline.org/doi/full/10.2214/AJR.07.3406

(2008)

Functionally the proximal TFJ is related to both the knee and the talocrural joint... In terms of human knee joint function, the fibular head merely serves as an attachment for the fibular collateral ligament and the adjoining tendon of the biceps femoris muscle as well as of the arcuate popliteal ligament and the lateral meniscus [13]. Moreover, slight conjoint axial rotation of the fibula in the proximal tibiofibular joint is an integral part of the talocrural joint.

 

As shown in Figures 6A and 6B, the fibula is externally rotated in dorsiflexion of the foot, thus allowing the broader anterior part of the trochlea tali to pass within the mortise formed by the malleoli. Thus, one of the primary functions of the proximal TFJ is believed to be dissipation of torsion force applied at the ankle joint [14]. The injury of the posterior and anterior ligaments of the fibular head may lead to instability of the proximal TFJ and also to deficiency of the active movements of the talocrural joint.

 

 

Type II dislocation

 

http://www.healio.com/orthopedics/journals/ortho/2008-6-31-6/%7B917fb67b-e331-4e0f-a23a-feb09eda348a%7D/isolated-acute-dislocation-of-the-proximal-tibiofibular-joint

(2008)

Type II (anterolateral dislocation) is the most common type of dislocation and involves injury of the anterior and posterior tibiofibular ligaments.1,6,9,22 The mechanism of injury usually includes a sudden inversion and plantar flexion of the foot with a simultaneous knee flexion and external rotation of the leg.6,9 The patient generally reports an incident of landing with a flexed knee under his or her body, when both the lateral collateral ligament and biceps femoris tendon are relaxed, predisposing the proximal tibiofibular joint to lateral displacement and injury.9,18

Type III (posteromedial dislocation), although rare, is most likely to have associated peroneal nerve injury. It usually is caused by either a direct hit or a twisting motion that tears the capsule and ligaments, including sometimes the lateral collateral ligament.1,6,10 The fibula head displaces posteriorly and medially along the posterolateral aspect of tibial metaphysis. Another mechanism of injury involves twisting of the leg with a violent contraction of the biceps femoris muscle, dislocating the head of the fibula posteriorly.23

 

Although peroneal nerve injury is mostly associated with Type III injuries, both Types II and III injuries are suggested by:

 

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1726224/pdf/v020p00563.pdf

(2002)

Tibiofibular head dislocations have been classified by Ogden, as subluxation only (type I), anterolateral (type II), posteriosuperior (type III), and superior (type IV), with type II being the most common.8 Types II and III are more likely to be associated with a peroneal nerve injury, the most common complication of this injury.

 

Is it a coincidence that additional stability is supplied to the two tibiofibular ligaments:

• by the popliteus tendon, crossing the joint posteriorly and reinforcing the posterior ligament,

• by the biceps femoris tendon, passing anterior to this ligament and inserting into the lateral side of the fibular head,

• and that a peroneal nerve injury is more likely to be associated with both of these...???

 

And these are all mimickers of a lateral meniscus tear as discussed by:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3445190/

(2008)

 

 

http://www.healio.com/orthopedics/journals/ortho/2008-6-31-6/%7B917fb67b-e331-4e0f-a23a-feb09eda348a%7D/isolated-acute-dislocation-of-the-proximal-tibiofibular-joint

(2008)

The major stability of the proximal tibiofibular joint is provided by the bony sulcus behind the lateral tibial condyle and the 2 tibiofibular ligaments.15 Additional stability is provided by associated ligaments and tendons.15 The anterior tibiofibular ligament is stronger than the posterior proximal tibiofibular ligament.6,15 The ligaments are reinforced by the popliteal tendon, which crosses the joint posteriorly and reinforces the posterior ligament and by the biceps femoris tendon which passes anterior to this ligament and inserts into the lateral side of the fibular head. The arcuate popliteal ligament and the cord-like lateral collateral ligament also insert on the fibular head and enhance stability.17,18 

 

In knee flexion, the biceps femoris tendon and lateral collateral ligament are lax, and the fibular head moves anteriorly and its stability decreases.19,20

In knee extension, the proximal fibula is pulled posteriorly because these same structures are tightened.19,20 As a result of the laxity in the joint capsule with flexion, injuries to this joint generally occur with the knee in a flexed position.

 

Limited rotatory and axial fibular motion is allowed in concert with ankle movements, and this can be felt by grasping the fibular head as the ankle is dorsiflexed and plantar flexed.15,18,20

 

 

The anterior tibiofibular ligament is stronger than the posterior proximal tibiofibular ligament... or in other words, the posterior proximal tibiofibular ligament is weaker and therefore more likely to tear. However this ligament has help with stability issues provided by the popliteus tendon, or perhaps more accurately, by the popliteofibular ligament which then helps out the popliteus tendon.

 

But the popliteus tendon is stretched on flexion of the knee... So is it likely that the popliteus tendon and/or popliteofibular ligament are also damaged, or subluxated and unable to supply the help needed by the damaged posterior tibiofibular ligament in order to maintain stability...???

 

 

http://www.healio.com/orthopedics/journals/ortho/2008-5-31-5/%7B91821d01-6dec-4790-87f5-140159a4f3d2%7D/acute-and-chronic-management-of-posterolateral-corner-injuries-of-the-knee

(2008)

The popliteus and popliteofibular ligament, in particular, have been shown to be the most important structures in resisting external rotation.

 

So is it possible that this left the popliteus muscle and tendon, and maybe the popliteomeniscal fascicles as well, insecure and unable to manouvre the lateral meniscus and prevent a radial tear...???

 

 

UNANSWERED QUESTIONS:

 

Is my proximal tibiofibular joint dislocated...? Stable when extended...?

Is the posterior proximal tibiofibular ligament intact...? Subluxated...?

Is the popliteofibular ligament intact...? Subluxated...?

Is the biceps femoris tendon intact...? Subluxated...?

Is the peroneal nerve fully-functional...? Subluxated...?

Is the extensor digitorum longus intact...? Subluxated...?

 

 

 

 

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2564106/

(2006)

 

Diagnosis is largely clinical, relying on suspicion for the injury.1 The findings on examination may be quite subtle, and are easily missed.2 Clinical features may include: lateral knee pain aggravated by pressure over the fibular head, limited knee extension, crepitus, visual deformity, and locking or popping.4,5 Ankle movement may exacerbate knee pain.4 There may be transient peroneal nerve palsy, especially with posterior or superior dislocations.4

 

AND knee movement may exacerbate ankle pain... ?