Lower Extremity: Hip
Epidemiology: The incidence of hip osteoarthritis is 88 per 100,000 with females more commonly affected than males. Risks factors include obesity, trauma, hard labor, muscle weakness, females, age, genetics, race (some Asians are at more risk).
Pathoanatomy: There is damage to the articular cartilage, inflammatory changes to the synovium and capsule, and bone cysts may form in late stages.
Presentation: Patients complain of groin pain and stiffness that is often worse in the morning. Patients will notice overall decreased Range of Motion of the hip joint.
Imaging: The mainstay is a weight-bearing view of the affected joint. Findings will include joint space narrowing, osteophytes, eburnation of the bone, subchondral sclerosis and subchondral cysts.
Diagnosis: The typical patient can be diagnosed with simple history, physical examination and plain x-rays. It is rare to need a CT scan or a MRI.
Treatment: NonOperative Management consists of NSAIDs, weight loss, exercise, and intra articular steroid injections. If those options fail to provide effective or lasting relief, the Operative Management consists of hip resurfacing or Total Hip Arthroplasty. Recent advances in technology have given THA many years of lasting relief. This procedure is generally well tolerated with an average of 3 month recovery. The most common complication would include dislocation and rarely infection.
Greater Trochanteric Bursitis:
Epidemiology: This entity most commonly occurs in female runners. It is associated with running on “turtle back” surfaces.
Pathophysiology: The repetitive trauma caused by the iliotibial band tracking over the trochanteric bursa can irritate and cause inflammation. The trochanteric bursa is superficial to the hip abductor muscles and deep to the iliotibial band. The places a “water balloon” or bursae in areas of high friction.
Presentation: Patients will commonly complain of lateral sided hip pain even though the hip joint is not the culprit. Patients will have pain with palpation over the greater trochanter of the proximal femur.
Diagnosis: Plain x-rays will be negative, but a MRI can show some increased signal in the bursae due to inflammation.
Treatment: Non Operative Management includes NSAIDs, stretching, formal Physical Therapy, and steroid injections in the bursae. Operative Management consists of open versus arthroscopic trochanteric bursectomy. Rarely, a Z lengthening of the iliotibial band in the region of the greater trochanter can be attempted.
Hip Labrum Tear:
Epidemiology: The highest incidence of labral tear is in patients with acetabular dysplasia. This can be seen in any age group but is most commonly seen in active females.
Pathophysiology: A common cause of labral tear is from Femoral Acetabular Impingement. The cam affect from the head and neck of the proximal femur impinges on the acetabulum and tears the labrum. A floppy labrum is more susceptible to tearing. A hip dislocation or subluxation may result in a torn labrum. Finally, degenerative joint disease of the hip can cause acetabular edge loading and result in labrum tear.
Presentation: Patients will complain of mechanical hip pain and snapping. They report vague groin pain and occasionally a sensation of locking. Physical examination can discern an anterior versus posterior labral tear.
Diagnosis: Plain x-rays can help to differentiate from other types of hip entities but cannot show the labrum because it is a cartilaginous structure. A MRI arthrogram or a 3T MRI without arthrogram is 92% sensitive for detecting labrum tears.
Treatment: NonOperative Management consists of rest, NSAIDs, Physical Therapy and intraarticular steroid injections. Operative Management consists of hip arthroscopy with labral repair or debridement.
Femoroacetabular Impingement (FAI):
Epidemiology: The concept of Cam impingement commonly refers to the femoral based disorder in young athletic males. The patients have a decreased head to neck ratio, aspherical femoral head, decreased femoral offset and femoral neck retroversion. The concept of Pincer impingement commonly refers to an acetabular based disorder in active middle aged women which includes anterosuperior acetabular rim overhang, acetabular, retroversion, acetabular protrusion, ad coxa profunda.
Pathoanatomy: The proximal femur abuts the acetabulum with range of motion. Flexion appears to be the most common offensive motion.
Presentation: Patients report activity related groin or hip pain. Patients will complain of pain with flexion, prolonged sitting, and occasional gluteal pain secondary to altered gait mechanics.
Diagnosis: Plain x-rays show an aspheric femoral head and neck with pistol grip deformity. A CT scan can be used to further access structural abnormalities such as acetabular protrusio, retroversion or coxa profunda. MRI can be used to evaluate the articular cartilage and labral tears.
Treatment: NonOperative Management consists of observation and possible intraarticular steroid injection for symptomatic relief. Operative Management falls into two categories. The arthroscopic hip procedure can debride the offensive boney structures through multiple arthroscopic portals using burs and shavers. The open surgical hip dislocation is used by some surgeons who preserve the blood supply to the hip and perform the debridement of the offending boney structures then reduce the hip and repair the capsule. This method provides wide exposure of the femoral head and acetabulum. They can repair or debride the labrum at this point.
Avulsion of the Anterior Superior Iliac Spine:
Epidemiology: ASIS avulsion fractures occur in young athletes through the physis on the iliac crest. The cause is a sudden and forceful contraction of the sartorius and tensor fascia lata. This is commonly associated with violent hip extension such as a track hurdler or sprinter or with swinging of a baseball bat.
Anatomy: The muscles that originate at the ASIS are the sartorius and the tensor fascia lata. A variation of this injury is the Anterior Inferior Iliac Spine which involves the Rectus Femoris muscle.
Presentation: Athletes will frequently report a snap or pop at the time of injury. They typically complain of weakness. Physical examination will see weakness to hip flexion with the knee fully extended (straight leg raise in a supine position). Some patients may present on crutches with a limp.
Imaging: Plain x-rays can demonstrate displaced fractures at the iliac crest physis. The x-rays should include an AP pelvis and bilateral Judet views. Subtle injuries might be missed. If the suspicion is high, a MRI can be ordered to confirm the diagnosis.
Treatment: Non Operative Management consists of rest, protected weight bearing, and early ROM with gently stretching. Operative Indications are displaced avulsion fractures with more than 3cm of displacement. The procedure consists of open reduction of the fragment and internal fixation with screws.