Second Rib Syndrome:

A POORLY MANAGED PAIN COMPLEX 

Shoulder pain is a common diagnosis for physical therapists and other healthcare providers to encounter, with recent global incidence rates as high as 62 per 1000 persons per year1. Despite its frequency, shoulder pain has generally poor outcomes, with only 50% of new episodes of shoulder pain presented in a primary care setting showing complete resolution by six months2. By one year, that number only improves to 60%2. In a randomized collection of 208 patients with shoulder pain, rotator cuff pathology was identified in 65% of patients via magnetic resonance arthrogram3. While common, the presence of a rotator cuff tear on imaging does not indicate that those tissues are the primary pain generators. A mass screening study performed in 2013 in a village in Japan found that 147 of the 664 (22.1%) patients had full-thickness rotator cuff tears, while one-half of the tears of people in their 50s and two-thirds of the tears of those over age 60 were entirely asymptomatic4. For patients who undergo rotator cuff repairs, it is reported that approximately 25% of repairs failed to remain intact and patient-reported outcomes measures were typically only <75% of the potential maximum improvement5. Despite improvements in diagnostic imaging, an increased prevalence of research on rotator cuff pathology, and advanced surgical techniques, outcomes from surgical repairs have not improved appreciably in the last 30 years5. Shoulder pain is, therefore, a condition that should respond well to conservative treatments, but the research shows that the medical system still fails to adequately address new onset of shoulder pain and provide long-term relief from symptoms. 

AN ISSUE OF SPECIAL TESTING

The problem with shoulder pain management may lie in false positives produced with tissue-specific special testing without follow-up with diagnostic ultrasound. Current literature cites fairly strong sensitivities and specificities for common shoulder special tests for rotator cuff pathologies. For supraspinatus tears, Jobe’s test had a sensitivity of 88% and a specificity of 62%. The full can test had a sensitivity of 70% and a specificity of 81%. For infraspinatus tears, the external rotation lag signs at 0° had a specificity of 98%, and the Hornblower’s sign had a specificity of 96%6. The Hawkins-Kennedy test has sensitivity of 74% and specificity of 57%, while Neer’s sign had a sensitivity of 78% and specificity of 58% in pooled studies7. Research has consistently shown that these tests may be diagnostically flawed, even when clustered, as they may present with pain and/or weakness when other structures are dysfunctional 8, 9, 10. Due to the frequent misdiagnosis and mismanagement of shoulder girdle pain, it is important to consider more central structures which may have both a direct and indirect effect on shoulder pain processes, specifically, the second and third ribs. 

THE CASE STUDIES11 

Two case studies presented by Boyle in 1999 highlight the connection of unilateral rib dysfunction to shoulder pain and weakness that often presents as rotator cuff pathology or impingement. His first patient was a 21 year old male reporting posterior shoulder pain and presenting with a diagnosis of a partial rotator cuff tear by his physician. He had positive tests for the Hawkins-Kennedy, full can, and empty can tests with both pain and weakness. While first rib and cervical mobility was normal, Boyle noted significant hypomobility and tenderness to palpation, and he selected to perform three rounds of 60 seconds of grade III posterior-anterior mobilizations. After treatment, the previously positive special tests were negative and the patient had full and pain free range of motion. The patient reported 90% improvement in his pain 24 hours after treatment and 100% improvement on day 3 and 7 follow-ups. 

The second patient Boyle discovered this rib dysfunction in was a 52 year old female who presented with shoulder pain after pulling weeds 5 months prior. She received 2 cortisone injections within 3 months, which provided minimal and only short-term relief of symptoms. She reported anterior, posterior, and central shoulder pain with shoulder active abduction limited to only 80 degrees. She also had a positive Hawkins-Kennedy test with both weakness and pain. Boyle also noted the same unilateral 2nd rib hypomobility and pain with spring testing, and he selected to treat with grade III posterior-anterior mobilizations for 3 bouts of 30 seconds. Immediately after treatment she reported significant pain reduction and was able to abduct fully without pain. Two days later, she tested negative on the Hawkins-Kennedy test and had full active range of motion without pain. 

PROPOSED MECHANISM OF DYSFUNCTION

The second rib tends to sublux or sprain in an anterior and superior direction, which is theorized to place pressure on or cause irritation to the dorsal ramus of the second thoracic nerve, which provides cutaneous innervation to the posterolateral shoulder as it travels laterally to the acromion12. The ramus travels through a vertical opening that can be entrapped caudally by the rib and laterally by the superior costotransverse ligament12. The rib may become subluxed either from acute injury or chronic facilitation of the posterior scalenes, which insert onto the 2nd rib and may cause repeated subluxation. 

ASSESSMENT AND TREATMENT

Per the 2015 Dunning study investigating the effects of ribs 2-3 high velocity low amplitude thrust manipulation (HVLAT) on shoulder girdle pain, useful clinical signs to confirm suspicions of rib dysfunction causing shoulder pain include: 1) familiar pain production and tenderness with posterior-anterior palpation over the 2nd or third ribs13 and 2) “unilateral pain between the neck and elbow at rest or during movement of the upper arm14.  Limited research supports the use of either mobilization or manipulation of the ribs on the affected side as treatment for this condition. Prior to manipulation, it is critical to rule out contraindications to HVLAT and determine red flags, such as, tumor, metabolic diseases, osteoporosis, hypertension, history of prolonged corticosteroid use, signs of upper motor neuron lesions, and unreproducible shoulder pain suggesting potential viscerosomatic referral. It is also important to perform differential diagnosis to exclude radicular symptoms from the cervical spine, including signs of herniated discs or nerve root compression13. Mobilization or HVLAT of the thoracic spine is also highly supported in the literature for immediate and significant pain reduction in patients with shoulder pain and would be beneficial to include while addressing rib dysfunction 15, 16, 17. 

REFERENCES 

1. Lucas, J., van Doorn, P., Hegedus, E., Lewis, J., & van der Windt, D. (2022). A systematic review of the global prevalence and incidence of shoulder pain. BMC musculoskeletal disorders, 23(1), 1073. https://doi.org/10.1186/s12891-022-05973-8

2. Croft P, Pope D, Silman A. The clinical course of shoulder pain: prospective cohort study in primary care. Primary Care Rheumatology Society Shoulder Study Group. Br Med J 1996;313:601–2.

3. Cadogan, A., Laslett, M., Hing, W. A., McNair, P. J., & Coates, M. H. (2011). A prospective study of shoulder pain in primary care: prevalence of imaged pathology and response to guided diagnostic blocks. BMC musculoskeletal disorders, 12, 119. https://doi.org/10.1186/1471-2474-12-119

4. Minagawa, H., Yamamoto, N., Abe, H., Fukuda, M., Seki, N., Kikuchi, K., Kijima, H., & Itoi, E. (2013). Prevalence of symptomatic and asymptomatic rotator cuff tears in the general population: From mass-screening in one village. Journal of orthopaedics, 10(1), 8–12. https://doi.org/10.1016/j.jor.2013.01.008

5. McElvany MD, McGoldrick E, Gee AO, Neradilek MB, Matsen FA 3rd. Rotator cuff repair: published evidence on factors associated with repair integrity and clinical outcome. Am J Sports Med. 2015. February;43(2): 491–500. Epub 2014 Apr 21.

6.  Jain, N. B., Luz, J., Higgins, L. D., Dong, Y., Warner, J. J., Matzkin, E., & Katz, J. N. (2017). The Diagnostic Accuracy of Special Tests for Rotator Cuff Tear: The ROW Cohort Study. American journal of physical medicine & rehabilitation, 96(3), 176–183. https://doi.org/10.1097/PHM.0000000000000566

7. Alqunaee M, Galvin R, Fahey T. Diagnostic accuracy of clinical tests for subacromial impingement syndrome: a systematic review and meta-analysis. 2012. In: Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-.

8. Leschinger, T., Wallraff, C., Müller, D., Hackenbroch, M., Bovenschulte, H., & Siewe, J. (2017). Internal Impingement of the Shoulder: A Risk of False Positive Test Outcomes in External Impingement Tests?. BioMed research international, 2017, 2941238. https://doi.org/10.1155/2017/2941238

9. Jia, X., Ji, J. H., Pannirselvam, V., Petersen, S. A., & McFarland, E. G. (2011). Does a positive neer impingement sign reflect rotator cuff contact with the acromion?. Clinical orthopaedics and related research, 469(3), 813–818. https://doi.org/10.1007/s11999-010-1590-3

10. Beaudreuil, J., Nizard, R., Thomas, T., Peyre, M., Liotard, J. P., Boileau, P., Marc, T., Dromard, C., Steyer, E., Bardin, T., Orcel, P., & Walch, G. (2009). Contribution of clinical tests to the diagnosis of rotator cuff disease: a systematic literature review. Joint bone spine, 76(1), 15–19. https://doi.org/10.1016/j.jbspin.2008.04.015

11. Boyle, JWW. (1999). Is the pain and dysfunction of shoulder impingement lesion really second rib syndrome in disguise? Two case reports. Manual Therapy;4(1):44-48.

12. Maigne JY, Maigne R, Guérin-Surville H. Upper thoracic dorsal rami: anatomic study of their medial cutaneous branches. Surgical and Radiologic Anatomy : SRA. 1991 ;13(2):109-112. DOI: 10.1007/bf01623882. PMID: 1925910.

13. Dunning, J, et al. (2015). Changes in shoulder pain and disability after thrust manipulation in subjects presenting with second and third rib syndrome. Journal of Manipulative and Physiological Therapeutics; 38(6):382-394.

14. GJ Bergman, JC Winters, KH Groenier, et al. (2004). Manipulative therapy in addition to usual medical care for patients with shoulder dysfunction and pain: a randomized, controlled trial

Ann Intern Med; 141: 432-439

15. Strunce, J. B., Walker, M. J., Boyles, R. E., & Young, B. A. (2009). The immediate effects of thoracic spine and rib manipulation on subjects with primary complaints of shoulder pain. The Journal of manual & manipulative therapy, 17(4), 230–236. https://doi.org/10.1179/106698109791352102

16. Cleland JA, Selleck B, Stowell T, et al. Shortterm effects of thoracic manipulation on lower trapezius strength. J Man Manip Ther. 2004;12:82–90.

17. Chitroda, J., & Heggannavar, A. (2014). Effect of thoracic and rib manipulation on pain and restricted shoulder mobility in subjects with frozen shoulder: A randomised clinical trial. Indian Journal of Health Sciences, 7(2), 92.