Chapter 20: The Knee Joint Complex

CHAPTER OBJECTIVES

At the completion of this chapter, the reader will be able to:

1. Describe the joint anatomy, ligaments, muscles, and blood and nerve supply that comprise the knee joint complex.

2. Describe the biomechanics of the tibiofemoral and patellofemoral joints, including the forces involved with closed-chain and open-chain activities, the open- and close-packed positions, normal and abnormal joint barriers, force couples, and joint stabilizers.

3. Describe the purpose and components of an examination for the knee joint complex.

4. Perform a detailed examination of the knee joint complex, including palpation of the articular and soft-tissue structures, specific passive and active mobility tests, stability tests, and special tests.

5. Understand the purpose of muscle function testing and extrapolate information from the findings.

6. Describe the significance of muscle imbalance in terms of functional muscle performance.

7. Outline the significance of the key findings from the history, the tests and measures of the knee joint complex, and establish a diagnosis.

8. Describe the common pathologies of the knee joint complex and their relationship to impairment.

9. Develop self-reliant intervention strategies based on clinical findings and established goals.

10. Apply active and passive techniques to the knee joint complex and surrounding structures, using the correct intensity and duration.

11. Evaluate intervention effectiveness to progress or modify the intervention.

12. Plan an effective home program, and instruct the patient in this program.

13. Help the patient to develop self-reliant intervention strategies.

OVERVIEW

The knee joint complex is elaborate and includes three articulating surfaces, which form two distinct joints in a single-joint capsule: the patellofemoral joint (PFJ) and the tibiofemoral joint. Anatomically and biomechanically, the tibiofemoral joint and the PFJ can be considered separate entities in much the same way as the craniovertebral joints are compared with the rest of the cervical spine. In 15–20% of the population, an accessory sesamoid bone in the gastrocnemius, the fabella, is part of the knee joint complex. The fabella, when present, articulates with the lateral femoral condyle and is hence an articular sesamoid.

The knee is one of the most commonly injured joints in the body. The types of knee injuries seen clinically can be generalized into the following three categories:

• Unspecified sprains or strains, and other minor injuries, including overuse injuries

• Contusions

• Meniscal or ligamentous injuries

The clinician must be familiar with the diagnostic and therapeutic procedures appropriate for all injury categories. It is also important that the clinician understand differential diagnosis, as pain in the thigh, knee, and calf can result from a broad spectrum of conditions.