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Less hip range of motion is associated with a greater alpha angle in people with longstanding hip and groin pain

Estberger, August LU ; Pålsson, Anders LU ; Kostogiannis, Ioannis LU orcid and Ageberg, Eva LU orcid (2021) In Knee Surgery, Sports Traumatology, Arthroscopy 29(12). p.4091-4099
Abstract

Purpose: A higher alpha angle has been proposed to correlate with lower hip range of motion, but the association in people with longstanding hip and groin pain is currently unclear. The aims were to: (1) assess the association between range of motion and alpha angle in patients with longstanding hip and groin pain; (2) examine if a cut-off value in range of motion variables could identify patients with an alpha angle above or below 60°. Methods: Seventy-two participants were consecutively recruited from an orthopaedic department after referral for hip- and groin-related pain. Passive hip range of motion was measured in flexion, internal rotation with 90° hip flexion, internal rotation in neutral hip position, external rotation with 90°... (More)

Purpose: A higher alpha angle has been proposed to correlate with lower hip range of motion, but the association in people with longstanding hip and groin pain is currently unclear. The aims were to: (1) assess the association between range of motion and alpha angle in patients with longstanding hip and groin pain; (2) examine if a cut-off value in range of motion variables could identify patients with an alpha angle above or below 60°. Methods: Seventy-two participants were consecutively recruited from an orthopaedic department after referral for hip- and groin-related pain. Passive hip range of motion was measured in flexion, internal rotation with 90° hip flexion, internal rotation in neutral hip position, external rotation with 90° hip flexion, and abduction. The alpha angle was calculated from a frog-leg lateral radiograph. Linear regression examined the association between range of motion and alpha angle, and an ROC-curve analysis was performed to identify the sensitivity and specificity of range of motion cut-offs. Results: Lower range of motion in internal rotation in flexion, external rotation, and abduction were associated with higher alpha angle. Internal rotation of 27° or less displayed good sensitivity (81%) and specificity (85%) to detect an alpha angle above 60°, while a cut-off of 41° in external rotation and 27° in abduction showed a sensitivity of 72% and specificity of 50% and 60%, respectively. Conclusion: Less internal rotation in flexion, external rotation, and abduction are associated with a greater alpha angle in a cohort of people with longstanding hip and groin pain. A cut-off of 27° in internal rotation has good sensitivity and specificity to identify people with an alpha angle above or below 60° and have the potential to be used in the clinical setting to identify patients that require further imaging, or that are unlikely to have cam morphology. Level of evidence: II.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Alpha angle, Cam morphology, Femoroacetabular impingement, Range of motion
in
Knee Surgery, Sports Traumatology, Arthroscopy
volume
29
issue
12
pages
4091 - 4099
publisher
Springer
external identifiers
  • pmid:34510222
  • scopus:85114819590
ISSN
0942-2056
DOI
10.1007/s00167-021-06733-2
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2021, The Author(s).
id
4c9fbc5f-0642-450c-83be-38fda56679c7
date added to LUP
2021-10-12 14:44:55
date last changed
2024-02-20 13:41:59
@article{4c9fbc5f-0642-450c-83be-38fda56679c7,
  abstract     = {{<p>Purpose: A higher alpha angle has been proposed to correlate with lower hip range of motion, but the association in people with longstanding hip and groin pain is currently unclear. The aims were to: (1) assess the association between range of motion and alpha angle in patients with longstanding hip and groin pain; (2) examine if a cut-off value in range of motion variables could identify patients with an alpha angle above or below 60°. Methods: Seventy-two participants were consecutively recruited from an orthopaedic department after referral for hip- and groin-related pain. Passive hip range of motion was measured in flexion, internal rotation with 90° hip flexion, internal rotation in neutral hip position, external rotation with 90° hip flexion, and abduction. The alpha angle was calculated from a frog-leg lateral radiograph. Linear regression examined the association between range of motion and alpha angle, and an ROC-curve analysis was performed to identify the sensitivity and specificity of range of motion cut-offs. Results: Lower range of motion in internal rotation in flexion, external rotation, and abduction were associated with higher alpha angle. Internal rotation of 27° or less displayed good sensitivity (81%) and specificity (85%) to detect an alpha angle above 60°, while a cut-off of 41° in external rotation and 27° in abduction showed a sensitivity of 72% and specificity of 50% and 60%, respectively. Conclusion: Less internal rotation in flexion, external rotation, and abduction are associated with a greater alpha angle in a cohort of people with longstanding hip and groin pain. A cut-off of 27° in internal rotation has good sensitivity and specificity to identify people with an alpha angle above or below 60° and have the potential to be used in the clinical setting to identify patients that require further imaging, or that are unlikely to have cam morphology. Level of evidence: II.</p>}},
  author       = {{Estberger, August and Pålsson, Anders and Kostogiannis, Ioannis and Ageberg, Eva}},
  issn         = {{0942-2056}},
  keywords     = {{Alpha angle; Cam morphology; Femoroacetabular impingement; Range of motion}},
  language     = {{eng}},
  number       = {{12}},
  pages        = {{4091--4099}},
  publisher    = {{Springer}},
  series       = {{Knee Surgery, Sports Traumatology, Arthroscopy}},
  title        = {{Less hip range of motion is associated with a greater alpha angle in people with longstanding hip and groin pain}},
  url          = {{http://dx.doi.org/10.1007/s00167-021-06733-2}},
  doi          = {{10.1007/s00167-021-06733-2}},
  volume       = {{29}},
  year         = {{2021}},
}