summary Spontaneous osteonecrosis of the knee (SONK) is an idiopathic condition that leads to the development of a crescent shaped osteonecrosis lesion, mostly commonly in the epiphysis of the medial femoral condyle. Diagnosis can be radiographic for advanced disease but may require MRI in determining the extent of disease. Treatment is generally nonoperative as most cases are self-limiting. Surgical management is indicated for progressive cases that fail conservative management. Epidemiology Demographics most common in middle age and elderly affects females (>55yo) more frequently than males Anatomic location 99% of patients have only one joint involved usually epiphysis of medial femoral condyle Etiology Pathophysiology may represent a subchondral insufficiency fracture also believed to be caused by a meniscal root tear Presentation Symptoms sudden onset of severe knee pain effusion limited range of motion secondary to pain tenderness over medial femoral condyle Imaging Radiographs recommended views standing AP and lateral of hip, knee and ankle MRI most useful study is helpful to confirm the diagnosis and assist in determining the extent of disease helping guide treatment considerations lesion is crescent shaped Differential Must differentiate from osteochondritis dissecans more common on lateral aspect of medial femoral condyle in adolescent males transient osteoporosis more common in young to middle age men bone bruises and occult fractures associated trauma, bone fragility or overuse Treatment Nonoperative NSAIDs, narcotics, protected weight bearing indications mainstay of treatment as most cases resolve technique physical therapy directed at quadriceps strengthening outcomes initial conservative measure and has shown good results Operative arthroplasty indications when symptoms fail to respond to conservative treatment outcomes successful results reported with TKA (larger lesions or bone collapse) and UKA (smaller lesions) when properly indicated high tibial osteotomy indications when angular malalignment present
QUESTIONS 1 of 6 1 2 3 4 5 6 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ15.258.2) A 62-year-old female Zumba instructor presents to your clinic reporting progressive left knee pain and effusion that has been present for the past few months. Pain is exacerbated by weightbearing and physical exam is significant only for TTP over the medial joint line. A radiograph and MRI are shown in Figures A-B. Which of the following statements regarding management of this pathology is true? QID: 213790 FIGURES: A B Type & Select Correct Answer 1 Unicompartmental knee arthroplasty (UKA) demonstrates reliable long-term outcomes when performed for this condition 56% (1033/1834) 2 UKA is appropriate for the spontaneous (but not secondary) form of this condition 7% (125/1834) 3 UKA performed for this condition is associated greater failure rates than for osteoarthritis 18% (323/1834) 4 The most common cause of failure following UKA for this condition is from tibial stress fractures 3% (58/1834) 5 Total knee arthroplasty (TKA) is indicated for this patient due to high failure rates associated with UKA when performed for this condition 16% (286/1834) L 4 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ08.99) A 59-year-old female librarian complains of progressively worsening left knee pain over the last 4 months. She does not recall any traumatic injury to the knee. Physical exam is noteable for tenderness isolated to the medial joint line. She has full ROM and no instability of the knee. Radiographs and MRI image are provided in figures A,B, and C. Which of the following is the best management? QID: 485 FIGURES: A B C Type & Select Correct Answer 1 Open biopsy 1% (51/3746) 2 Chest CT and bone scan 2% (92/3746) 3 Osteochondral autograft transfer 22% (842/3746) 4 Unicompartmental knee arthroplasty 70% (2631/3746) 5 Valgus-producing high tibial osteotomy 3% (107/3746) L 3 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE07HK.17) A 74-year-old woman has had acute medial right knee pain for the past 3 months. She denies any history of trauma or previous problems. Coronal and sagittal MRI scans are shown in Figures 11a and 11b. What is the most likely diagnosis? QID: 5977 FIGURES: A B Type & Select Correct Answer 1 Osteoarthritis 10% (72/713) 2 Rheumatoid arthritis 0% (3/713) 3 Medial meniscal tear 9% (61/713) 4 Osteonecrosis 73% (524/713) 5 Transient osteoporosis 6% (46/713) L 3 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic
All Videos (0) Podcasts (1) Knee & Sports⎜Spontaneous Osteonecrosis of the Knee (SONK) Knee & Sports - Spontaneous Osteonecrosis of the Knee (SONK) Listen Now 12:52 min 10/21/2019 547 plays 5.0 (4)
osteonecrosis lateral femoral condyle right knee (C2165) Dimitris Zikos Knee & Sports - Spontaneous Osteonecrosis of the Knee (SONK) E 3/2/2015 274 1 15 Transient Osteoporosis of the Knee / AVN Femoral Condyle (C1803) Dimitrios Konstantis Knee & Sports - Spontaneous Osteonecrosis of the Knee (SONK) E 2/27/2014 118 2 4 Osteochondritis of the Knee? (C1390) Dimitrios Konstantis Knee & Sports - Spontaneous Osteonecrosis of the Knee (SONK) E 1/18/2013 231 2 10