Pathophysiology in terms of tendon and bursa PLUS chondromalacia

Pathophysiology of knee injury
Tendon:
The tendon at the knee is the quadriceps tendon. A ruptured quadriceps tendon can injure the knee. The rupture usually occurs 0-2cm distally from the superior pole of the patella.
Hamstring tendon rupture

The hamstring muscles consist of the Biceps femoris, Semitendinosus and Semimembranosus. The muscles insert at the back of the knee through tendons. It is possible for these tendons to be torn during an explosive or kicking movement.


Patella tendon rupture
The patellar tendon is prone to rupturing in individuals with a history of patellar tendon injury such as jumpers knee or degeneration due to age. Injuries of this type serve to weaken the patellar tendon and in the event of strong eccentric quadriceps contraction (contraction during lengthening of the muscle), such as landing from jump, the patella tendon may snap or rupture most commonly at the lower end of the patella.
Jumper’s knee
What is jumpers knee / patellar tendinopathy?
The patella tendon / ligament joins the kneecap (patella) to the shin bone or tibia (video). This tendon is extremely strong and allows the quadriceps muscle group to straighten the leg. The quadriceps actively straighten the knee in jumping to propel the individual off the ground as well as functioning in stabilizing their landing.
As such this tendon comes under a large amount of stress especially in individuals who actively put extra strain on the knee joint such as those who regularly perform sports that involve direction changing and jumping movements. With repeated strain, micro-tears as well as collagen degeneration may occur as a result in the tendon.


Bursa:
The pre-patellar bursa lies between the patella and the skin. An example of an inflamed bursa that causes knee pain is the pre-patellar bursitis which is the housemaid’s knee. Acute pre-patellar bursitis can be caused by a direct blow or fall on the knee. The ruptured blood vessels will bleed into the bursa which causes it to swell and trigger inflammation reaction in the bursa wall. The wall, thus thickens which causes tenderness. Infection due to surface injury can also trigger bursitis. Bacteria may enter the wound and spread into the fluid. This will lead to infection.

The infrapatellar bursa can be divided into superficial and deep components. The superficial component lies between the patellar ligament and the skin, while the deep component lies between the patellar ligament and the proximal anterior tibia.
Infra-patellar bursitis also known as clergyman’s knee, is caused by friction between the skin and the bursa. This may happen in conjunction with jumper’s knee. Clinically, the patient exhibits pain with flexion and extension at the extremes of the range of motion. Edema is located on both sides of the patellar tendon and is tender.

Chondromalacia
Chondromalacia patellae is the softening and degeneration of the tissue (cartilage) underneath the kneecap (patella). Chondromalacia is also known as runner’s knee. Chondromalacia patellae may also result from a blow to the patella or extreme flexion of the knee (during squatting when power lifting). Under the kneecap is a layer of smooth cartilage which glides effortlessly across knee during bending of the joint. In chondromalacia, the deepest layer of the cartilage changes and this cause blister of the surface cartilage.

ooo. the photos are gone. ghee

real sorry for being late.