#455 Sports Injuries Part 2: Hip and Knee

September 30, 2024 | By Edison Jyang

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De-stress your approach to stress fractures (and trochanteric pain syndromes and meniscus tears)!

Follow along as the great Dr. Senter guides us through the diagnosis, workup, and treatment of an all-star lineup of sport injuries. Part 2 covers stress fractures, relative energy deficiency in sports, trochanteric pain, meniscus tears, and the ongoing quest to diagnose Paul’s mysterious hip injury. 

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Show Segments

• Case 1 – Hip stress fracture 
• Approach to hip injuries in runners  
• Relative Energy Deficiency in Sports (RED-S)
• Imaging consideration for bone stress injuries
• Surgical and treatment consideration for hip stress fractures
• Osteoporosis evaluation
• Case 2 – Greater trochanteric pain syndrome 
• Hip and trochanter anatomy  
• Treatment and imaging of trochanteric tendinopathies
• Case 3 – Meniscus tear
• Knee evaluation and physical exam  
• Bucket handle tears and surgical considerations
• Special physical exam maneuvers 
• Imaging and further surgical considerations 
• Outro & Take Home Points 

Sports Injury Pearls

1. Musculoskeletal complaints in the primary care clinic can be approached with the framework of HIPROT: History, Inspection, Palpation, Range of motion, and Other Tests. 
2. The diagnosis of stress fractures or low bone density in athletes should prompt consideration of Relative Energy Deficiency in Sport (RED-S),  and subsequent assessment of nutritional status and menstrual history. 
3. Remember to use Z scores and not T scores for bone density assessment of pre-menopausal patients. Additionally, the American College of Sports Medicine considers Z scores of less than -1 to be indicative of low bone density in athletes, rather than the conventional less than -2. 
4. Patients with tension side (lateral) femoral neck stress fractures should have emergent orthopaedic surgery consultation. Compression side (medial) femoral neck stress fractures can often be managed conservatively. 
5. Newer studies have illustrated that trochanteric pain is rarely “bursitis,” but in fact usually tendinopathy of the surrounding structures! Consider the involvement of surrounding gluteal tendons, IT band, and tensor fasciae latae. 
6. Physical therapy and corticosteroid injections can both be effective for treatment of trochanteric pain, particularly in the short term, however, steroid injections may not be as effective in the long term. 
7. Identifying patients with meniscus tears who would benefit from surgery can be complex. Factors that favor surgical intervention are acute tears versus chronic or degenerative tears, younger patients versus older, and lack of concurrent osteoarthritis of the knee. 
8. Patients with meniscus tears and symptoms of joint “locking” should be made non-weight-bearing and urgently referred to an Orthopedic surgeon for evaluation for surgery to treat a bucket handle tear. 

Sports Injuries Part 2 – Show Notes

Stress Fracture of the Hip 

Risk Factors 

It is helpful to have athletes quantify their activity, particularly in miles per week in the case of runners. Those at the higher end of the spectrum have a higher risk of bone stress injuries. Dr. Senter begins to worry about these around the range of 20-30 miles per week. 

Screen for other risk factors for low bone density, including prior history of stress fractures, history of low bone mineral density, delayed menarche, low energy availability with or without disordered eating, medications (PPIs, corticosteroids, anticonvulsants, aromatase inhibitors, certain chemotherapies), smoking and alcohol intake, etc. (Joy 2005). 

Relative Energy Deficiency in Sport (RED-S) 

A stress fracture in a young athlete should raise concern for RED-S. The intensity of athletic training can lead to a supply-demand mismatch of the body’s energy. This was previously known as the female athlete triad (typified by low energy availability with or without disordered eating, oligomenorrhea and/or amenorrhea, and low bone density), and is a complex and developing sports medicine concept in athletes regardless of gender (Mountjoy 2014). 

Manifestations of this condition can include low bone density (athletic activity should increase bone density!), secondary amenorrhea in female athletes (technically “functional hypothalamic amenorrhea”), mood changes, anemia, decreased athletic performance, increased cardiovascular risk through lipid dysfunction, and numerous other downstream effects (Mountjoy 2014). 

Screening for this condition should include a detailed menstrual and nutritional history. Dr. Senter reminds us that athletes often have a complicated relationship with diet since a light and small body habitus is often advantageous in certain sports. Discussion of disordered eating should be approached with care and sensitivity. 

Management 

When there is a concern for a femoral neck stress fracture, patients should be made non-weight bearing (on crutches) and sent for an immediate AP and lateral x-ray. While poorly sensitive in the early stages, these can immediately identify a stress fracture (break in the cortex) if present, however would not be able to identify a stress injury (region of increased osseous metabolic activity without cortical disruption). 

If x-rays are negative but bone stress injury is still highly suspected, it is reasonable to pursue urgent MRI as it has the most favorable sensitivity and specificity (Wright 2016). 

When a fracture is identified, it is crucial to identify whether it is on the compression side (medial) or tension side (lateral), as patients with tension fractures need to be sent to the ED for urgent surgery. This is because they have a much higher risk of progression to complete fractures that may require a hip replacement. However, Dr. Senter recommends that in general, femoral neck fractures should be discussed with an Orthopedic specialist, as some patients with severe compression side fractures will benefit from surgery as well (DeFranco 2006). 

Fractures that do not require surgery are typically handled with conservative measures. Patients should be counseled up front that this is a slow process, and they may not be running again for at least 3 months. Dr. Senter typically approaches this with two weeks of non-weight bearing on crutches, then advancing from weight bearing as tolerated to full weight bearing over a period of 4–6 weeks. She will then generally approach their “return to sport” by advancing their activity (walking) by around 10% per week, however, this is predominantly expert opinion-based. 

Such injuries should also prompt consideration of DEXA scanning for bone density measurement. Remember to use the Z-score for pre-menopausal patients, not the T-score. The American College of Sports Medicine considers a Z score of less than -1 to be low in athletes, which is more conservative than the traditional mark of less than -2. Low bone density should prompt evaluation of vitamin D levels as well as other labs to evaluate for causes of low bone density, and possibly connection with a registered dietician +/-psychologist as appropriate for concerns of inadequate fueling or disordered eating (Mountjoy 2014, Nattiv 2007). 

Trochanteric Pain

Relevant Trochanteric Anatomy (and the Myth of “Trochanteric Bursitis”) 

Previous clinical practice had grouped most trochanteric pain under the presumed diagnosis of “trochanteric bursitis,” however, modern studies supported by MRI and ultrasound have found that this is often not the case! While inflammation of the bursa itself can occur, this is rare. Much more commonly, pain in that region can come from tendinopathy of the surrounding structures (Bird 2001, Speers 2017). 

Important attachments to the greater trochanter include: 

• Posterior – gluteus medius insertion
• Superior – tensor fascia latae insertion
• Inferior – Iliotibial (IT) band insertion

The pathology of these structures typically consists of chronic tendonitis, partial tears, or calcification (although calcification typically presents with quite severe pain) (Bird 2001). 

Imaging

In general, if the diagnosis of a trochanter-related tendinopathy is quite clear without other complications, Dr. Senter does not recommend x-rays or advanced imaging at the start of treatment. If the pain is quite severe, x-rays could be helpful in identifying calcific tendonitis. X-rays or MRI may be reasonable in patients not responding to conventional measures as below. 

Management

Like most tendinopathies, these can be treated primarily with physical therapy (Mellor 2018). The tenocytes themselves can regenerate, however this is often slow and painful since tendons do not have as robust a blood supply as muscles do. For patients that may not have ready access to physical therapy, Dr. Senter recommends the rehab resources provided on UCSF’s Sports Medicine Rehab site. 

Corticosteroid injections are also commonly used and effective at pain relief. One study found them to be potent in reducing symptoms in the short term, however they were not as effective as PT in global improvement at 52 weeks (Mellor 2018). Dr. Senter discussed how the role of corticosteroid injections has recently come under scrutiny. This is due in part to extrapolation from studies showing worse long term outcomes of steroid injections for elbow tendinopathies potentially blunting the inflammatory repair process, however further study is needed (Bisset 2006, Coombes 2010, Couppe 2022). In a similar vein, Dr. Senter reports that the role of NSAIDs and icing are a growing hot topic among sports medicine physicians as far as the balance of therapeutic inflammation versus pain control. 

Meniscus Injuries 

Dr. Senter uses a memorable and effective approach to musculoskeletal issues: HIPROT

H – HISTORY

In this case of knee pain and suspected meniscus tear, she clarifies a few key points. Is the patient experiencing any: 

• Swelling? This could be indicative of a joint effusion. The timing of this is helpful as well. Patients with ACL tears develop an effusion immediately due bleeding from the ACL’s artery, whereas patients with a meniscus tear will develop an effusion after a few hours. 
• Locking? Many patients confuse “clicking” or “catching” for locking, which is actually when the patient is truly unable to move the joint. Locking can be a red flag for a “bucket handle” tear, requiring urgent surgery to salvage the meniscus. 
• Instability? By this she is looking for more than patients reporting they “feel unstable,” but rather if there is translation of the femoral condyles along the tibial plateau. If present, this would raise concern for knee ligament tears. 

History taking should of course also cover common items such as duration of symptoms, mechanism of injury, triggers, therapies tried, etc. This patient’s history of trauma in a twisting motion is particularly classic for meniscus injury. 

I – Inspection

Expose the joint, ideally having the patient in shorts or a gown. Visualize it for gross abnormalities, deformities, atrophy, discoloration, etc. The patient’s gait may be inspected as well. 

P – Palpation

This would include along the joint line to assess for point tenderness, ideally with the patient seated and legs off of the ground. With the patient supine, ballottement (or “squishiness”) would indicate an effusion. 

R – Range of motion

This is most effectively done with the patient lying down, and first assessing the unaffected side followed by the symptomatic side. In the case of meniscus tears, this could also identify any “locking.” 

OT – Other Tests

This is where specialized maneuvers are performed. For a suspected meniscus tear, these should include: 

• Medial and lateral McMurray test: Ask the patient to lie supine. The examiner flexes the affected knee fully. Hold the patient’s foot with one hand, and the affected knee in the other, the examiner flexes and extends the knee (bringing the foot towards and away from their pelvis), applying internal rotation and varus stress and then external rotation with valgus stress to put pressure on lateral and medial menisci respectively. Assess for any pain or “popping” sensations. Sensitivity ranges from 51-53%, and specificity varies widely from 59 to 97% (Jackson 2003, Ockert 2010, Solomon 2001). 
• Thessaly test: A favorite of Drs. Senter and Williams, this test can also be a whimsical test of balance if the patient can tolerate it. Test the unaffected side first, then the affected side. Have the patient stand on one foot with the knee very slightly flexed, then pivot on the knee in alternating directions in a gentle “dancing” motion. Medial or lateral joint line pain can indicate a tear in that respective meniscus. Sensitivity and sensitivity can be as high as 90 to 96% for meniscus tears (Harrison 2009), but studies vary. 
• Squat test: Have the patient go through a squat motion. Lateral or medial joint pain may indicate a meniscus tear, while anterior pain can indicate patellofemoral pain. 
• For a full video walk-through of the knee exam, Dr. Senter recommends UCSF Ortho’s YouTube page, which has both brief and extensive demonstrations of the knee exam. 

As a general knee assessment of athletic injuries, integrity of the ACL/ PCL/ MCL/ LCL should be assessed as well. 

Imaging

Workup should begin with x-rays of the joint, which serve several purposes. For one, it can evaluate for alternate diagnoses such as osteoarthritis or fracture. Additionally, the presence of osteoarthritis can have implications for future surgical considerations. However, meniscus damage will not be seen on x-ray. 

The decision to pursue MRI is complex and highly dependent on the individual patient. In broad strokes, MRI is often done when surgery is being considered, and forgone when conservative management is pursued. However, the decision to go to surgery is also laden with gray areas, as seen below. 

Dr. Senter also considers how this injury is affecting the lifestyle and occupation of her patients when ordering the urgency of the MRI. 

Management

Conservative measures such as rest, ice, compression and elevation can be initiated while awaiting MRI and surgical decision making. 

The approach to definitive treatment of meniscal tears is challenging. Surgery can be effective for young patients with acute injuries and otherwise healthy cartilage (Chatain 2003), however it has been found to have no advantage over physical therapy and conservative treatment of osteoarthritis in older patients with degenerative meniscus tears and osteoarthritis (Bassett 2017, Kise 2016). 

One clearer example is that of patients with the red flag of “locking” of the knee, which can indicate bucket handle tears. These should be evaluated with urgent MRI. Bucket handle tears should be immediately referred to an Orthopedic specialist to repair the meniscus. 

In general, surgical decisions for unclear cases should usually be made in conjunction with a Sports Medicine or Orthopedic specialist.

Links

1. UCSF’s Sports Medicine Rehab Resources (instructional videos on joint strengthening)
2. UCSF Ortho’s Youtube page (detailed videos on physical exam maneuver)

Goal

Listeners will develop a framework to work up sport-related injuries including stress fractures, trochanteric pain, and meniscus injuries. 

Learning objectives

After listening to this episode listeners will…  

1. Be able to identify risk factors and manifestations of RED-S. 
2. Know the imaging and surgical considerations of stress fractures. 
3. Know the relevant anatomy and evolving treatment of trochanteric pain syndromes. 
4. Be able to perform a nuanced physical exam of the hip and knee. 

Disclosures

Dr. Senter reports no relevant financial disclosures. The Curbsiders report no relevant financial disclosures. 

Citation

Jyang E, Wikoff P, Senter C, Achi S, Williams PN, Watto MF. “#455 Sports Injuries Part 2: Hip and Knee”. The Curbsiders Internal Medicine Podcast. thecurbsiders.com/category/curbsiders-podcast Final publishing date September 30, 2024.