Cholesterol and Rotator Cuff Pathology - An Overlooked Element in Shoulder Rehab

Hello!

Today I am excited to discuss the most up-to-date research surrounding the role of cardiovascular disease - specifically high cholesterol - in the development and recovery of rotator cuff pathology.

Rotator cuff injuries are the most common cause of shoulder pain, and they are present in 50% of individuals over age 60 [1]. While we often attribute these injuries to overuse, repetitive strain, heavy lifting, and poor posture, what has been gravely overlooked is the role of cholesterol in the development of these conditions, and how it impacts the healing time and quality in both non-surgical and surgical cases.

The rotator cuff consists of 4 muscles, which are involved in both mobility and stability of the shoulder joint:

• supraspinatus

• infraspinatus

• subscapularis

• teres minor

In contrast to common perspective, repetitive strain, overuse, and poor posture are not as closely linked with rotator cuff injury as we'd previously thought.

According to a 2021 longitudinal cohort study of 5 years conducted by Grusky et al, [2] it was found that older age, hand dominance, high BMI were independently associated with rotator cuff tears. What this means is that regardless of other factors such as occupation and posture, these factors are strong contributors to the condition.

On a similar note, multiple studies have concluded that in addition to these three factors, smoking and hypertension are among the strongest contributors to the development of rotator cuff injuries [3-8].

If you ask a physiotherapist how they feel about treating rotator cuff injuries, some will tell you they love it, and others will cringe as they reflect on the many patients they've encountered who just wouldn't get better, no matter what they did. Shoulder injuries can be very tricky to treat, and as I reflect on the countless rotator cuff injuries I've seen as both a PT and PTA, I can begin to piece together the puzzle, noticing patterns that were once unidentifiable to me. It goes a little something like this:

"Tell me how I can help you today"

"I've got this shoulder injury, it's been hurting for ____ weeks/months/years".

As I proceed to gather more information, I, just like any other physiotherapist, ask about additional health issues, illnesses, conditions, hobbies, stress, etc.

While I can't give a specific number, a significant proportion of individuals I've treated with a rotator cuff injury have told me they've got high cholesterol, or diabetes, or hypertension.

"I'm just on blood pressure meds, that's it".

"I take cholesterol medication, otherwise I'm healthy".

"I have type 2 diabetes, but it's managed and my blood work is good".

The usual response from myself, and likely most other physiotherapists is something along the lines of "thank you, now let's move on".

We ask these questions, and proceed to do nothing with the information, in part because we don't realize how relevant it is. We are taught to look at the whole person in school, but when it comes down to the daily grind, how often are we putting these puzzle pieces together?

The answer is: not often enough.

A Dive Into Dyslipidemia

Dyslipidemia is the fancy term for high cholesterol. In typical cases of dyslipidemia, triglycerides, total cholesterol, and low density lipoprotein (LDL) will be elevated, while high density lipoprotein (HDL) decreases [1]. Some of the primary causes of dyslipidemia include smoking, dietary habits, and obesity, though the causes can be much more complex in some cases. This is an issue of increasing importance, considering 45% of Canadians and 53% of Americans aged 18+ have dyslipidemia. Statins, the most common medication prescribed for this condition, cost the Canadian healthcare system $2 billion annually [1].

While the exact process of rotator cuff pathology in relation to dyslipidemia requires more research, what we do know is that excess lipids accumulate in the extracellular space of tendons, which impacts the way they function [9]. Lipid accumulation also impairs the ability of tendons to heal due to their pro-inflammatory properties [1].

Where's the Proof?

Correlations have been made between dyslipidemia and achilles xanthomas (fat deposits), tendinopathies, and ruptures [10,11]. More recent evidence has been investigating the pathological processes and healing of rotator cuff tendons in the presence of dyslipidemia as well.

In a 2017 systematic review consisting of 9 studies which evaluated a total of over 500,000 patients, two thirds (66%) showed statistically significant relationships between dyslipidemia and rotator cuff pathology [1].

A 2018 systematic review evaluated 16 studies across Europe, North America, and Asia that assessed triglyceride levels in individuals with and without rotator cuff tears. 10 of the 16 studies identified a correlation between dyslipidemia and the presence of rotator cuff tears, noting that triglycerides, LDL, and total cholesterol were all higher in individuals with rotator cuff tears compared to those without [9].

In 2015, Lin et al. did a retrospective cohort study of just under 500,000 patients [12] Hyperlipidemia was found to be an independent risk factor for rotator cuff disease, while multiple studies [13-15] have noted an increased need for post-operative revisions due to poor healing in those with dyslipidemia.

Last, a recent systematic review and meta analysis (2018) evaluated the effect of lipid disorders on the risk of developing rotator cuff disease. This review included 7 studies with 505,000 patients, and identified an odds ratio of 2.17 for developing rotator cuff disease in the presence of dyslipidemia [16]. For those of you who aren't statisticians, a 2.17 odds ratio translates to:

Individuals with lipid disorders have 117% higher odds of developing rotator cuff injuries

OR

Individuals with lipid disorders have 2.17x higher odds of developing rotator cuff injuries.

What Can We Do About It?

As physiotherapists, we play a key role in reducing the burdens of cardiovascular disease through movement therapy. A combination of strength and endurance training can help manage symptoms and assist in controlling lipid levels in conjunction with traditional statin therapy [17]. Often, when treating rotator cuff pathologies, we prescribe exercises that may initially look like this:

which is totally fine!

However, what clinicians may be overlooking (myself included) is the prescription of aerobic exercise into our shoulder plans. We readily prescribe this type of activity to people with chronic back pain, obesity, fibromyalgia, and those experiencing frailty or deconditioning, however, when it comes to isolated injuries and localized pain, it may not be our top priority.

We know that resistance training is beneficial for those with rotator cuff pathology and those with cardiovascular disease, and we know that aerobic training has particularly strong benefits for those with high cholesterol.

If we know that aerobic exercise can reduce "bad cholesterol", and we know that high cholesterol is associated with rotator cuff pathology, then we may begin to consider increasing our prescription of aerobic activity for our patients who have both rotator cuff pathology and dyslipidemia. I'd love to know your thoughts and experiences!

*For the sake of length, I will not discuss research on aerobic exercise in depth. Please review the references for more detail.

References:

[1] MacDonald AE, Ekhtiari S, Khan M, Moro JK, Bedi A, Miller BS. Dyslipidaemia is associated with an increased risk of rotator cuff disease: a systematic review. Journal of ISAKOS. 2017 Sep 1;2(5):241-6.

[2] Grusky AZ, Song A, Kim P, Ayers GD, Higgins LD, Kuhn JE, Baumgarten KM, Matzkin E, Jain NB. Factors Associated With Symptomatic Rotator Cuff Tears: The Rotator Cuff Outcomes Workgroup Cohort Study. Am J Phys Med Rehabil. 2021 Apr 1;100(4):331-336. doi: 10.1097/PHM.0000000000001684. PMID: 33443862; PMCID: PMC7969413.

[3] Yazdani AN, Rai V, Agrawal DK. Rotator Cuff Health, Pathology, and Repair in the Perspective of Hyperlipidemia. Journal of Orthopedics and Sports Medicine 4 (2022): 263-275.

[4] May T, Garmel GM. Rotator cuff injury. (2019).

[5] Gumina S, Arceri V, Carbone S, et al. The association between arterial hypertension and rotator cuff tear: the influence on rotator cuff tear sizes. J Shoulder Elbow Surg 22 (2013): 229-232

[6] Bishop JY, Santiago-Torres JE, Rimmke N, et al. Smoking Predisposes to Rotator Cuff Pathology and Shoulder Dysfunction: A Systematic Review. Arthroscopy 31 (2015): 1598-1605

[7] Hattrup SJ. Rotator cuff repair: relevance of patient age. J Shoulder Elbow Surg 4 (1995): 95-100

[8] Sayampanathan AA, Andrew TH. Systematic review on risk factors of rotator cuff tears. J Orthop Surg (Hong Kong) 25 (2017): 2309499016684318

[9] Yang Y, Qu J. The effects of hyperlipidemia on rotator cuff diseases: a systematic review. Journal of Orthopaedic Surgery and Research. 2018 Dec;13:1-1.

[10] von Bahr S, Movin T, Papadogiannakis N, Pikuleva I, Rönnow P, Diczfalusy U, Björkhem I. Mechanism of accumulation of cholesterol and cholestanol in tendons and the role of sterol 27-hydroxylase (CYP27A1). Arteriosclerosis, thrombosis, and vascular biology. 2002 Jul 1;22(7):1129-35.

[11] Klemp P, Halland AM, Majoos FL, Steyn K. Musculoskeletal manifestations in hyperlipidaemia: a controlled study. Annals of the Rheumatic Diseases. 1993 Jan 1;52(1):44-8.

[12] Lin TT, Lin CH, Chang CL, Chi CH, Chang ST, Sheu WH. The effect of diabetes, hyperlipidemia, and statins on the development of rotator cuff disease: a nationwide, 11-year, longitudinal, population-based follow-up study. The American journal of sports medicine. 2015 Sep;43(9):2126-32.

[13] Cancienne JM, Brockmeier SF, Rodeo SA, Werner BC. Perioperative serum lipid status and statin use affect the revision surgery rate after arthroscopic rotator cuff repair. The American Journal of Sports Medicine. 2017 Nov;45(13):2948-54.

[14] Garcia GH, Liu JN, Wong A, Cordasco F, Dines DM, Dines JS, Gulotta LV, Warren R. Hyperlipidemia increases the risk of retear after arthroscopic rotator cuff repair. Journal of shoulder and elbow surgery. 2017 Dec 1;26(12):2086-90.

[15] Kim YK, Jung KH, Kim JW, Kim US, Hwang DH. Factors affecting rotator cuff integrity after arthroscopic repair for medium-sized or larger cuff tears: a retrospective cohort study. J Shoulder Elb Surg. 2018;27:1012–20

[16] Lai J, Gagnier JJ. The effect of lipid disorders on the risk of rotator cuff disease: A systematic review and meta-analysis. JBJS Open Access. 2018 Sep 9;3(3).

[17] Wang Y, Xu D. Effects of aerobic exercise on lipids and lipoproteins. Lipids Health Dis. 2017 Jul 5;16(1):132. doi: 10.1186/s12944-017-0515-5. PMID: 28679436; PMCID: PMC5498979.

[18] Mann S, Beedie C, Jimenez A. Differential effects of aerobic exercise, resistance training and combined exercise modalities on cholesterol and the lipid profile: review, synthesis and recommendations. Sports medicine. 2014 Feb;44:211-21.

[19] Ismail KA, Elsayyad L, Allam HH, Alzahrani N, Gharib AF. Effect of short-term aerobic exercise on lipid profile. Biomed Sci J. 2020 Jun 3;1(05).

[20] Docherty S, Harley R, McAuley JJ, Crowe LA, Pedret C, Kirwan PD, Siebert S, Millar NL. The effect of exercise on cytokines: implications for musculoskeletal health: a narrative review. BMC Sports Science, Medicine and Rehabilitation. 2022 Dec;14(1):1-4.

[21] Clifford C, Challoumas D, Paul L, Syme G, Millar NL. Effectiveness of isometric exercise in the management of tendinopathy: a systematic review and meta-analysis of randomised trials. BMJ open sport & exercise medicine. 2020 Aug 1;6(1):e000760.