Table 2.

Prevalence of cam deformity in white male control subjects and Asian control subjects and Asian patients undergoing THA: cam morphotype prevalence varies with ethnicity, age, and imaging parameters

Study	Population	Age	Imaging	Parameter measured	Percent cam morphotype
Murray, 1965 [59]	25 English male control subjects	–	AP pelvic radiographs	“Head tilt deformity” femoral head ratio (FHR) > 1.35	10%
Nötzli et al., 2002 [65]	17 Swiss male control subjects with ≥ 20° internal rotation in 90° flexion	30 ± 5 years	MRI	Alpha angle > 50° at 3:00 position	0%
Gosvig et al., 2010 [28]	1332 Danish male control subjects population study	60 ± 13.6 years	AP pelvic radiographs	“Pistol grip deformity” triangular index	19.6%
Reichenbach et al., 2010 [75]	244 Swiss male control subjects 18-year-old army recruits	19.9 years	Radial MRI	Decreased offset head-neck junction anterior quadrant (0–3:00)	24%
Hack et al., 2010 [30]	90 Canadian male control subjects (79% whites)	29.4 years	Radial MRI	Alpha angle > 55° at 1:30 position	51.6%
Pollard et al., 2010 [72]	39 English male control subjects without hip signs or symptoms	47.5 ± 12 years	Crosstable lateral radiographs	Alpha angle > 62°	2.6%
Laborie et al., 2011 [44]	874 Norwegian male control subjects population study	18.6 ± 0.6 years	AP pelvic radiographs	Pistol-grip deformity focal femoral neck prominence flattening of lateral femoral head	21.5% pistol-grip deformity; 10.3% focal neck prominence; 14.4% flattening of femoral head
Toogood ≤ 50 years [99]	140 US (Cleveland) cadaver femora; 50% whites and 50% blacks	37 years	Photographs	Alpha angle > 55° at 3:00 position	18.6%
Toogood et al., 2009 (> 50 years) [99]	48 US (Cleveland) cadaver femora; 50% whites and 50% blacks	63 years	Photographs	Alpha angle > 55° at 3:00 position	43.8%
Kim, 1989 [43]	172 Korean fetuses; 67 male adult cadavers; 244 male Korean adults hospitalized for other reasons than hip	14–38 weeks 60.6 years 58.4 years	Caliper measurement/244 AP pelvic radiographs	Femoral head sphericity (caliper); femoral head sphericity (caliper); femoral head sphericity (Mose ring on radiograph)	“Spherical femoral heads in fetal and adult cadavers”; spherical femoral heads on radiographs, “no pistol grip”
Takeyama et al., 2009 [93]	158 Japanese male patients undergoing THA	–	Preoperative crosstable lateral radiographs	Alpha angle > 60°	1.6%
Nakahara et al., 2011 [62]	21 Japanese male control subjects (36 hips)	72.7 ± 5.7 years	Three-dimensional CT	Alpha angle > 55° at 1:00 position	25%