Hip Strength and Stability
The hip joint is a ball-and-socket joint with massive ligaments, which make the hip quite stable and able to prevent many injuries. The bony anatomy, muscles, labrum and ligaments of the hip all contribute to its strength and stability. The ball and socket is sealed by the hip labrum, a ring of cartilage that helps with movement between the leg and the pelvis.The hip ligaments are structures that are primarily responsible for maintaining smooth hip motion, keeping the hip in place, while it moves in a pain-free, strong and stable fashion.
What Causes Hip Injuries?
Even though the hip has been known for its strength and stability in the past, hip injuries have become increasingly recognized as a source of pain and disability. This makes sense when one considers we move our hips at least one million times per year during activities of daily living. The high rates of wear and tear, attributable to normal use of the hip alone can result in long term problems. Add to that sports activities, and the requirements on athletes to become bigger and stronger, places more and more force on the hip. These tremendous forces increase every year, which sheds light on our understanding of the growth in hip injuries. When the soft tissue structures of the hip, such as the labrum, tendons, and ligaments are subjected to forces beyond their normal range, injury and failure occur, resulting in hip joint injury and instability.
Types of Hip Injuries
Hip injuries are common in sports activities like soccer, ice hockey and football. But they also include overuse injuries from repetitive use in activities like, cycling, yoga, hiking, aerobics and more. Symptoms from overuse injuries often have an insidious onset, and become residual and chronic. Hip injuries cause instability of the hip, which is demonstrated in abnormal movement between the structures of the hip joint, and is associated with an array of hip conditions, including labral tears, femoroacetabular impingement, ligament tears, dislocations and osteoarthritis.
One of the most common conditions is dislocation of the hip. Hip dislocations are seen in sports like football, rugby, hurling and soccer, and they commonly occur posteriorly due to the greater strength of the anterior capsule of the joint. The individual is hit in the front of the thigh, forcing the thigh/hip complex backward, resulting in the hip dislocation and injury to the ligamentum teres and the posterior capsule. A joint dislocation significantly disrupts all the structures that support the joint. Long-term consequences of posterior hip dislocations can include sciatic nerve injury, avascular necrosis of the femoral head and significant arthritis and cartilage damage.
Laxity of the anterior hip capsule is seen in sports injuries and overuse injuries. Activities that demand supraphysiologic joint motion such as figure skating, dance and gymnastics are causative factors. The ileofemoral ligament of the anterior hip capsule may stretch out causing a focal rotational type of instability. This type of instability can cause labral tears and associated pain.
Stances repeatedly taken by athletes such as hockey goalies and baseball catchers can cause overuse injuries and may lead to femoroacetabular impingement (FAI). However, the most common cause of FAI is simply some type of soft tissue injury such as an iliofemoral or ischiofemoral ligament injury. Over time, hip instability from ligament injuries as well as a hip labral tear can cause premature arthritis and FAI. The association between hip instability from athletic injuries and the development of arthritis has been well documented.
A thorough understanding of hip anatomy and cause of instability are essential to the management of hip instability and initiation of treatment. In the majority of cases, the physician should be able to find the correct cause of instability with history taking, clinical examination and radiographs. Imaging such as MRI and MRI arthrography are also helpful. Evaluation of hip range of motion including flexion, internal/external rotation in flexion, abduction and adduction should be performed with comparison to contralateral hip, to confirm the presence of instability.
How Are Hip Injuries Treated?
The majority of hip instability cases can be managed non-surgically. Surgical intervention is required in cases of large acetabular fractures. Standard therapeutic approaches (pain medications, corticosteroid injections and arthroscopy) employed to address hip instability have often been ineffective, because they do not repair the underlying cause of the problem, the injured ligaments and labrum.
Non-surgical regenerative therapies including Stem Cell Therapy, PRP, and Prolotherapy are alternative modalities that can repair the instability by stimulating the natural regenerative processes in and around the hip joint to facilitate the restoration of the degenerated ligaments and labrum to a healthy state, improving joint support, function and reducing pain and symptoms.
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