Weekly Case

Title : Case 698

Age / Sex : 58 / M

Chief complaint : left knee pain and swelling after acupuncture procedure

What is your diagnosis?

Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).

Courtesy : 김여주 (Yeo Ju Kim) 한양대학교 서울병원 (Hanyang University Medical Center)



HADD (Hydroxy apatite deposition disease) involving lateral collateral ligament and adjacent bursa of left knee



Knee X ray: In plain radiograph, there are several cloudy amorphous calcifications at paraarticular region of lateral tibiofemoral joint. Suspicious localized osteopenia at lateral femoral epicondyle.

MRI of knee: Coronal T2 WI shows several amorphous low signal intensity lesions along the lateral collateral ligament (LCL) and the medial aspect of the LCL. In contrast enhanced coronal T1 WI, the low signal intensity lesions are again seen with peripheral enhancement and edema. The LCL also shows periligamentous enhancement. There is mild bone marrow edema at lateral epicondylar region.

CT and duel energy CT (DECT) of knee: In CT, there is faint calcific densities at the paraarticular region of lateral tibiofemoral joint, corresponding with the X ray and MRI. There is no definite green colorization representing monosodium urate crystal, at the calcific density in DECT.

Considering of the calcification morphology, location, and no green colorization in DECT make a diagnosis of HADD. After conservative treatment, he relieved symptom and the calcific densities gradually decreased their density and amount in follow-up X ray.


Differential Diagnosis:

Gout, CPPD



HADD (Hydroxy apatite deposition disease)

  • Common cause of calcific tendinitis/ bursitis

  • Calcium hydroxyapatite deposition in tendon, ligament, bursa

    • Not birefringent

    • Alizarin red staining: sensitive but not specific

    • Amorphous, dense soft tissue calcification

    • Repeated minor trauma and calcium hydroxyapatite deposition in necrotic tissue

    • Degenerated or injured tendons through a process of fibrocartilaginous metaplasia

  • Middle aged, M = F

  • bilateral in up to 50% of patients (symptomatic in 10– 50%)

  • Monoarticular, acutely painful condition

  • Inflammatory reaction without structural abnormality

  • Periarticular >> intraarticular

    • Shoulder- rotator cuff, SASD bursa, biceps tendon

    • MCP, IP: periarticular deposition

    • Wrist: tendon flexor carpi ulnaris insertion

    • Hip tendons (hamstring, gluteus)

  • X ray/CT

    • Formative phase: homogeneous dense

    • Resorptive phase: cloudy, poorly defined opacities

      • +/- bony erosion

      • +/- HA extension into bone

    • MRI:

      • Low (dark) signal on T1 and T2 WI

      • Surrounding enhancement, edema and bursitis



 1) Garcia GM, McCord GC, Kumar R. Hydroxyapatite crystal deposition disease. Semin Musculoskelet Radiol. 2003 Sep;7(3):187-93. 

2) Freire V, Moser TP, Lepage-Saucier M. Radiological identification and analysis of soft tissue musculoskeletal calcifications. Insights Imaging. 2018 Aug;9(4):477-492. 

Correct Answer
Total applicants 24 Correct answers 13
Name Institution
이연옥 선한목자병원, 전문의
이민욱 충남대학교병원, 전문의
여현정 전문의
임윤진 단국대학교병원, 전공의
이진영 전문의
이혜란 전문의
백승진 분당차병원, 전공의
윤나연 전공의
박선영 한림대학교 성심병원, 전문의
정치형 단국대학교병원, 전공의
이승보 서울아산병원, 전문의
김성진 365병원, 전문의
최형인 전공의
Semi-Correct Answer
Total applicants 24 Semi-Correct answers 3
이현규 전문의
김기욱 전문의
이규정 국군대전병원, 전문의