Purpose
To systemically describe posterior bone defects in the setting of posterior shoulder
instability based on several parameters, including surface area, slope and version,
defect height from the base of the glenoid, and extent of bone loss at equal intervals
along the long axis of the fossa.
Methods
A total of 40 young, active individuals with recurrent posterior shoulder instability
and a bony injury confirmed on either computed tomography (n = 18; mean age, 26.3
± 4.0 years) or magnetic resonance imaging (n = 22; mean age, 20.0 ± 4.9 years) were
identified. The posterior glenoid bone defect was characterized using the following
measures: (1) percentage of bone loss, (2) glenoid vault version, (3) slope of the
posterior defect relative to the glenoid surface, (4) superior-inferior length of
the defect, and (5) anterior-posterior width of the defect at 5 intervals along the
glenoid fossa.
Results
The mean age of the 40 patients was 22.9 ± 5.5 years (range, 14.9-35.5 years). The
mean surface area of glenoid bone loss was 9.7% ± 4.7%. Glenoid version measured at
5 equal intervals along the inferior two-thirds of the glenoid was 12.8° ± 4.9°, 11.9°
± 5.0°, 10.1° ± 6.3°, 10.5° ± 6.5°, and 8.7° ± 7.2° from superior to inferior. The
mean slope of the posterior defect relative to the glenoid fossa was 26.8° ± 11.5°.
The mean superior-inferior height of the bony defect was 21.9 ± 0.4 mm. The anterior-posterior
sloped width of the defect at 5 equal intervals along the glenoid fossa was 0.9 ±
1.5 mm, 2.8 ± 2.4 mm, 4.0 ± 1.7 mm, 4.0 ± 2.1 mm, and 2.9 ± 2.6 mm from superior to
inferior. Low-grade (<10%) bone loss was diagnosed in most shoulders (23 of 40 evaluated),
whereas 15 had moderate bone loss (10% to <20%) and 2 had high-grade bone loss (≥20%).
Conclusions
Posterior glenoid bone loss is characterized by a loss of posterior bony concavity,
increased slope from anterior to posterior, and increased posterior version. The most
anterior-posterior sloped width was quantified at the third and fourth intervals of
5 equal intervals from superior to inferior. This study highlights that patients with
posterior instability have bone loss that is sloped relative to the glenoid fossa
and suggests that management must be appropriately tailored given the distinctiveness
of posterior bone loss.
Level of Evidence
Level IV, case series.
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to ArthroscopyAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- Posterior instability of the shoulder: Diagnosis and management.Am J Sports Med. 2011; 39: 874-886
- Recurrent shoulder instability: Current concepts for evaluation and management of glenoid bone loss.J Bone Joint Surg Am. 2010; 92: 133-151
- Posterior shoulder instability in the athletic population: Variations in assessment, clinical outcomes, and return to sport.World J Orthop. 2015; 6: 927-934
- Risk factors for posterior shoulder instability in young athletes.Am J Sports Med. 2013; 41: 2645-2649
- Management of the failed posterior/multidirectional instability patient.Sports Med Arthrosc. 2010; 18: 149-161
- A biomechanical study of posterior glenoid bone loss and humeral head translation.J Shoulder Elbow Surg. 2010; 19: 994-1002
- The importance of the recognition and treatment of glenoid bone loss in an athletic population.Sports Health. 2011; 3: 435-440
- Pathologic changes associated with shoulder dislocations. Arthroscopic and physical examination findings in first-time, traumatic anterior dislocations.Am J Sports Med. 1997; 25: 306-311
- Glenoid bone deficiency in recurrent anterior shoulder instability: Diagnosis and management.J Am Acad Orthop Surg. 2009; 17: 482-493
- Assessment and evaluation of glenoid bone loss.Arthrosc Tech. 2016; 5: e947-e951
- Posterior shoulder instability: Does glenoid retroversion predict recurrence and contralateral instability?.Arthroscopy. 2015; 31: 488-493
- Excessive retroversion of the glenoid cavity. A cause of non-traumatic posterior instability of the shoulder.J Bone Joint Surg Am. 1986; 68: 724-731
- Posterior glenoid rim deficiency in recurrent (atraumatic) posterior shoulder instability.Skeletal Radiol. 2000; 29: 204-210
- Recurrent posterior shoulder instability.J Bone Joint Surg Am. 2005; 87: 883-892
- Posterior shoulder instability: Current concepts review.Knee Surg Sports Traumatol Arthrosc. 2011; 19: 1547-1553
- Iliac bone-block autograft for posterior shoulder instability.Orthop Traumatol Surg Res. 2009; 95: 100-107
- Operative stabilization of posterior shoulder instability.Am J Sports Med. 2005; 33: 996-1002
- Posterior bone block procedure for posterior shoulder instability.Knee Surg Sports Traumatol Arthrosc. 2007; 15: 1130-1136
- Arthroscopic capsulolabral reconstruction for posterior instability of the shoulder: A prospective study of 200 shoulders.Am J Sports Med. 2013; 41: 2005-2014
- Three-dimensional magnetic resonance imaging quantification of glenoid bone loss is equivalent to 3-dimensional computed tomography quantification: Cadaveric study.Arthroscopy. 2017; 33: 709-715
- Glenoid rim morphology in recurrent anterior glenohumeral instability.Am J Bone Joint Surg. 2003; 85: 878-884
- Computed tomography measurement of glenoid vault version as an alternative measuring method for glenoid version.J Orthop Surg Res. 2014; 9: 17
- Classification of glenohumeral joint instability.Clin Orthop Relat Res. 2002; 400: 65-76
Article info
Publication history
Published online: August 23, 2019
Accepted:
May 1,
2019
Received:
October 15,
2018
Footnotes
The authors report the following potential conflicts of interest or sources of funding: J.P.B. receives IP royalties from Arthrex. M.T.P. is a consultant for Arthrex and JRF Ortho; owns patents 9226743, 20150164498, 20150150594, and 20110040339; receives IP royalties from Arthrex; and receives publishing royalties from SLACK. Full ICMJE author disclosure forms are available for this article online, as supplementary material.
See commentary on page 2785
Identification
Copyright
© 2019 Published by Elsevier on behalf of the Arthroscopy Association of North America
ScienceDirect
Access this article on ScienceDirectLinked Article
- Editorial Commentary: Open Posterior Shoulder Stabilization—When Is It Needed? Glenoid Bone Loss Patterns Are Not Created EqualArthroscopyVol. 35Issue 10
- PreviewPosterior shoulder instability remains a poorly understood pathologic entity. Our current treatment algorithm of simple posterior shoulder instability is fairly straightforward, with most patients receiving arthroscopic capsulorrhaphy with labral repair. However, in those with a failed arthroscopic intervention and/or with bony pathology, the optimal treatment is much less clear. As we move forward to evaluate how to optimally treat these patients, it will be critical to better understand the bony pathologies, including those with true posterior glenoid bone loss versus glenoid retroversion.
- Full-Text
- Preview
