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Femoroacetabular Impingement (FAI)


Femoroacetabular impingement (FAI) is a condition where bony prominences exist on the bones that form the hip joint (femoral head and acetabulum) giving these bones an irregular shape. The bony prominences cause impingement on the soft tissue structure around the hip known as the labrum with hip range of motion. Over time, the labrum becomes partially detached and the cartilage adjacent to the labrum often peels up (delaminates). The healthy labrum forms a suction seal around the hip and when it is injured, microinstability can result due to partial loss of this seal. The muscles around the hip begin to overcompensate for this microinstability causing hip pain. The most common complaint associated with symptomatic FAI is groin pain.

Patients at risk for symptomatic FAI typically include athletes or very active individuals. Symptoms can begin as early as teenage years to one's 30s. Symptoms from FAI can also occur later on, but once arthritis sets in, arthroscopic treatment becomes less effective. Therefore, in older patients with FAI who have developed arthritis, hip replacement may be a better option. It is important to be evaluated to determine which treatment is best for you. Diagnosis is made with a thorough history, exam and imaging that includes X Rays and typically and MRI. If you are a young, healthy and active patient with chronic hip pain, call 413-785-4666 to make an appointment with Dr. Connor Ziegler.




While there are different causes of femoroacetabular impingement, developmental abnormalities of the hip occurring during the childhood or adolescence appear to be the most supported. The formation of bony prominences on the femoral head (ball) and acetabulum (socket) during adulthood or from certain sports activity are also attributable. The bony prominence on the femoral head-neck region is called a Cam lesion, while the bony prominence on the acetabulum is called a Pincer lesion (see above). Most cases of FAI involve a combination of the two.


The most common symptom reported in symptomatic FAI is groin pain. Pain may be constant, but more typically is episodic. Pain is often related to activity such as walking, jogging, turning, twisting, and squatting, which may cause a sharp, stabbing pain. Sometimes, the pain is just a dull ache. Patients may also feel catching or clicking sensations within the joint. It is also common to describe pain or stiffness after driving or prolonged sitting. 


There is a lot of information regarding hip pain and injuries on the internet and social media, but much of it is not coming from a doctor with many years of specialized training. Getting the correct information is important. The hip is a very complex structure and appropriate diagnosis is key to select the best course of treatment for optimal outcomes. This is best handled by a physician who specializes in treating conditions of the hip. If you are a young, healthy and active patient with chronic hip pain, call 413-785-4666 to make an appointment with Dr. Connor Ziegler.


Most patients with symptomatic FAI undergo a period of nonoperative treatment, which is definitely worth attempting but often provides only short-term benefit. Most insurance companies will require a minimum of 6 months of activity modifications, documented physical therapy and other modalities, injections, and use of non-steroidal anti inflammatory drugs (NSAIDs) such as ibuprofen or naproxen before approving surgical treatment.


Physical therapy helps to strengthen the hip, which is very important and will improve surgical outcomes. You should, however, avoid activity or excessive stretching that recreates your hip pain or makes your symptoms worse. A physical therapy referral can be obtained from you appointment with us. Until beginning a dedicated formal therapy program, here is a resource to help you get started on strengthening your hip. Like most strengthening programs, consistency is key.


AAOS Hip Conditioning Program (link).

Treatment of hip impingement used to primarily involve open surgery with larger incisions and in some cases still does. Arthroscopic treatment, however, has become the much more common method as it is less invasive and recovery is quicker. Since FAI often is associated with a labral tear, arthroscopic surgery will typically involve shaving down the bony prominences and repair of the labrum. Other procedures may also be indicated during the arthroscopic surgery as well, especially if there is cartilage damage. This cartilage damage is not always readily apparent on MRI and severity is best determined by looking at it with the arthroscopic camera during surgery. Follow the links below to learn more about hip arthroscopy and hip labral tears.

Hip Arthroscopy (link).

Hip Labral tears (link).


The hip arthroscopic surgery is performed as an outpatient and you will go home the day of surgery. You will be flat-foot weight bearing on your operative lower extremity for 3 weeks (can put foot flat, but no additional weight) and must use crutches for 4 weeks.  Physical therapy begins immediately, preferably the day after surgery, to prevent scar tissue formation. Therapy is immensely important to your outcome. You cannot expect to make maximal improvement if you are not dedicated to the therapy program. You also cannot make up for lost time. Most patients require 3-6 months for a full recovery and return to normal activity.



The best data we have to date, with minimum 10 years of follow-up (long-term), comes from the team at the Steadman-Philippon Research Institute. In 2017, they published a landmark article that has substantiated the benefit of hip arthroscopy. In their prospective study, hip arthroscopy for FAI resulted in significant improvements in patient reported outcomes and high satisfaction of patients who did not eventually require total hip replacement. Higher rates of conversion to total hip replacement were seen in older patients, patients treated with acetabular microfracture (procedure for full thickness cartilage lesions), and hips with less than 2 mm of joint space on preoperative X Rays (arthritis). Of the 34% of patients that went onto total hip replacement within 10 years following hip arthroscopy, the average age of these patients was 53 years at the time of the arthroscopy. Most of these patients also had joint space less than 2 mm (arthritis). In contrast, the average age of the patients who did not undergo total hip replacement was 35 years. Regardless of age, 89% of those with less than 2 mm of preoperative joint space underwent THA within 10 years. Therefore, younger patients with FAI who do not have hip arthritis typically do very well and are very satisfied with hip arthroscopy.

Survivorship and Outcomes 10 Years Following Hip Arthroscopy for Femoroacetabular Impingement: Labral Debridement Compared with Labral Repair (link).


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