The purpose of this study was to evaluate whether simple bone cysts (SBC) resolve with age.

Twenty four subjects with SBC who participated in a prior randomized clinical trial but had not healed at trial conclusion were evaluated for cyst healing. The following clinical and radiographic data were evaluated: age, sex, pain (Visual Analogue Scale), functional health (Short Form 36), subsequent fracture, involved bone, cyst area (cm), distance from physis (cm), endosteal thickening (yes/no), scalloping (no new scalloping/new scalloping), opacity/radiolucency (as is), loculation (yes/no), trabeculation (yes/no), tubulation (yes/no), transition zone (sharp/wide), geographic borders (geographic nonpermeative/nongeographic permeative), radiodense rim (>50%/no rim), and growth plate status (open/closed). Cyst healing was graded as: 1-cyst clearly visible; 2-cyst visible but multilocular and opaque; 3-sclerosis around or within a partially visible cyst; or 4-complete healing with obliteration of cyst. Healing was defined as grade 4.

Of 24 subjects, 15 (63%) were male, 18 (75%) cysts were located in the humerus, and 4 (25%) in the femur. Patients were followed for 7.0±1.0 years following initial treatment with a mean age at follow-up of 17.2±3.2 years and 14 (87%) of growth plates were closed. Pain was minimal (0.6/10), function was high (91/100), and none of the patients had experienced subsequent fractures. Although distance from physeal scar had increased (P< 0.0001), cyst area reduction (P< 0.1) and overall cyst healing (P< 0.2) had not changed. Of the 24 subjects, none were graded as healed at time of follow-up. Of the remaining radiographic variables, only decreased loculation (P< 0.02) and increased endosteal thickening (P< 0.04) showed significant changes.

Despite the assumption that most SBC will resolve with skeletal maturity, this study indicates that none of the cysts were graded as completely healed although 87% of growth plates were closed.

Growth plate closure may not signify healing of SBC and although symptoms and fractures are rare, further studies are needed to follow patients with SBC through early adulthood.

Polls results

On a scale of 1 to 10, rate how much this article will change your clinical practice?

NO change
BIG change
87% Article relates to my practice (7/8)
0% Article does not relate to my practice (0/8)
12% Undecided (1/8)

Will this article lead to more cost-effective healthcare?

62% Yes (5/8)
37% No (3/8)
0% Undecided (0/8)

Was this article biased? (commercial or personal)

0% Yes (0/8)
100% No (8/8)
0% Undecided (0/8)

What level of evidence do you think this article is?

0% Level 1 (0/8)
25% Level 2 (2/8)
62% Level 3 (5/8)
12% Level 4 (1/8)
0% Level 5 (0/8)