Perioperative complications and outcomes in patients with paraplegia undergoing rotator cuff repair

Abstract

Background

Patients with paraplegia often experience chronic shoulder pain due to overuse. We sought to determine if these patients have an increased prevalence of perioperative complications and higher rates of re-admissions and rotator cuff re-tears relative to able-bodied controls following rotator cuff repair (RCR).

Methods

We queried the NRD (2011–2018) to identify all patients undergoing primary RCR (n = 34,451) and identified cohorts of matched paraplegic and non-paraplegic patients (n = 194 each). We compared demographic factors, comorbidity profiles, perioperative complication rates, length of stay, revision rates, and re-admission rates between the two groups.

Results

Patients with paraplegia had lower rates of chronic obstructive pulmonary disease (p = 0.02), hypertension (p = 0.007), congestive heart failure (p = 0.027), obesity (p < 0.001), and prior myocardial infarction (p = 0.01). Additionally, patients with paraplegia experienced higher rates of urinary tract infections (11.9% vs. 2.1%, p < 0.001), lower rates of acute respiratory distress syndrome (0% vs. 3.1%, p = 0.041), and had a longer length of stay (4-days vs. 1-day, p < 0.001). Revision rates were similar for the two groups.

Conclusions

Compared to matched controls, patients with paraplegia were found to have similar demographic characteristics, less comorbidities, similar perioperative complication rates, and similar revision rates. These findings address a gap in the literature regarding surgical management of shoulder pain in patients with paraplegia by providing a matched comparison with a large sample size.

Keywords

Paraplegia rotator cuff repair rotator cuff tear

Introduction

With the incidence of spinal cord injuries in the United States increasing, the number of individuals living with paraplegia has increased.¹ This patient population relies heavily on their upper extremities for activities of daily living, including wheelchair transfers and propulsion, and reaching for overhead objects. This constant use and high pressure placed on the shoulder joint often leads to chronic pain, with as many as 71% of patients with paraplegia reporting some degree of shoulder pain,² as well as joint and rotator cuff pathology such as tears of the rotator cuff muscle tendons.^3,4 Rotator cuff tears (RCT) are commonly observed in wheelchair-dependent patients with paraplegia, affecting around 63% of these patients, compared with only 15% of able-bodied individuals.³ The presence of rotator cuff pathology in wheelchair-dependent patients is correlated with patient age and the duration of wheelchair use,^2,5 and the risk of a tear occurring increases by 6% with each year of wheelchair use.⁴

Shoulder pain and dysfunction in these patients is often initially managed using conservative, non-invasive strategies such as pharmacotherapy and exercise-based regimens.^6,7 However, the presence of an RCT often requires a multidisciplinary evaluation with consideration of surgical intervention.⁷ This approach requires the careful inclusion of imaging studies as magnetic resonance imaging evident shoulder pathology is almost always present in wheelchair-dependent patients, regardless of pain or functional impairment.⁸ Therefore, radiographically evident RCT must also be evaluated clinically and in the context of the specific patient. Additionally, the size of the tear and dominance versus non-dominance of the affected extremity are important factors to consider when determining management strategies, as larger tears and those on the dominant limb have a higher propensity to re-tear following surgical repair.⁹

Previous reports of surgical repairs of torn rotator cuffs in patients with paraplegia suggest that surgical management leads to clinically significant improvements in function and pain scores.^10–13 However, the decision to opt for surgical intervention is not made lightly for these patients, as considerable post-operative management is required to ensure favorable outcomes. For example, patients with paraplegia often remain in the hospital or a long-term care facility following rotator cuff repair (RCR) for up to 10 weeks post-op, with considerable restrictions to limit use of the repaired shoulder.^9,10,12 In contrast, able-bodied counterparts usually undergo RCR as an outpatient procedure, with some complicated cases requiring a hospital stay up to 4 days, depending on the surgical approach used.¹⁴ The extensive hospital stay and postoperative management that is necessary for patients with paraplegia following RCR place a huge burden on these patients, as immobilization of the involved upper extremity makes performing activities of daily living extremely difficult.

The possibility of the repaired rotator cuff re-tearing and the risk of perioperative complications are factors that must be considered when counseling these patients about treatment options. Previous reports document that patients with paraplegia experience high rates of perioperative complications following other shoulder surgeries such as reverse total shoulder arthroplasty (TSA),^15–17 but little information exists on the perioperative complications seen in this patient population following RCR. Studies of this nature are often limited to small sample sizes and lack a control group, while perioperative complications and surgical outcomes following RCR have been extensively investigated in able-bodied individuals. To date, no study exists that provides analyses of the perioperative outcomes of RCR in paraplegic patients using a large nationwide database. The aim of this study is to determine if patients with paraplegia undergoing RCR have an increased prevalence of perioperative complications and higher rates of re-admissions and rotator cuff re-tears relative to able-bodied controls using the Healthcare Cost and Utilization Projection Nationwide Readmission Database (HCUP NRD). We hypothesize that patients with paraplegia will have an increased prevalence of rotator cuff re-tears within the first year following surgery and higher rates of perioperative complications due to the functional limitations faced by these patients, as well as the burden of surgical recovery.

Methods

Database

For this study the HCUP NRD was queried. This database, in its unweighted form, accounts for 58.2% of United States hospitalizations. Data were collected between 2011 and 2018.

Control matching

All patients in the NRD database who received an RCR (8363 / 0LQ20ZZ / 0LQ23ZZ / 0LQ24ZZ / 0LQ10ZZ / 0LQ13ZZ / 0LQ14ZZ) were identified, providing 34,451 unique patients. Of those, 243 were diagnosed with paraplegia (3441 / G8220 / G8221 / G8222). From here on out, the hospitalization in which the patients received their RCR is referred to as the original visit of interest (OVI). Patients who met any of the following criteria were removed from the database: (1) died within the OVI or death status was missing, (2) left and right RCR within the OVI, (3) underwent any surgery indicating a past or present total shoulder or hemi-arthroplasty, and (4) received additional invasive procedures unrelated to the RCR or shoulder region that would likely occur in the operating room (e.g. total hip arthroplasty) or involved dialysis. The additional invasive procedures were removed due to their ability to cause adverse outcomes and confound the results. Patients who received procedures within the OVI that were apart of diagnostic testing, measurement taking, vaccine or medication administration, urinary catheterization, physical therapy, venous or cardiac catheterization, infusions, vascular access device implantation, or were an outcome of interest (e.g. transfusions) were kept as long as none of the removal criteria were met. To ensure that urinary catheterization, venous or cardiac catheterization, infusions, and vascular access device implantation procedures did not impact the complication and readmission rates, the prevalence of these procedures was compared between the patients with paraplegia and those without.

Control matching was conducted using the Case-Control Matching function on IBM SPSS Statistics for Windows, version 25 (IBM Corp., Armonk, NY, USA). Patients with paraplegia were matched with controls using the following factors: (1) discharge quarter, (2) sex, (3) age, (4) the primary expected payer for the hospitalization, and (5) the median household income based on their zip code. Patients were matched by their discharge quarter to ensure that the matches had similar lengths of follow-up time available, as the NRD only tracks patients within one calendar year. All of the above factors were matched exactly except for age, which individuals could match with someone within 3 years of their own age. Patients with missing data in the five matching factors were removed. Patients with paraplegia who did not receive a match were also removed. In total, there were 388 patients included in our analyses, consisting of 194 matched pairs of patients with paraplegia and patients without paraplegia.

Revisions, total shoulder arthroplasty, and readmissions

Follow-up hospitalizations for the 194 matches were extracted from the NRD database. Patients who received an additional RCR on the same side as their original RCR were considered to have received a revision. Total shoulder and hemi-arthroplasty were designated by the following codes and were considered in the follow-up only if they occurred on the same side as the original RCR of interest: 8180 / 8188 / 8181 / 0RRJ0JZ / 0RRK0JZ / 0RRJ00Z / 0RRK00Z / 0RRJ0J6 / 0RRJ0J7 / 0RRK0J6 / 0RRK0J7. Readmissions included any hospitalization for any reason following the OVI.

Statistical analysis

All statistics were conducted in RStudio version 1.2.5033 (RStudio, Inc., Boston, MA, USA; http://www.rstudio.com/). Matching our cohorts caused them to not be considered independent samples. All binary variables were evaluated using the McNemar’s test with the continuity correction and had one degree of freedom. The Wilcoxon-Signed Rank test with the continuity correction was used to analyze the number of readmissions per patient and the length of stay. The five comorbidities that were significantly different between those with and without paraplegia were used in an adjusted analysis to account for potential confounding in the following outcomes: length of stay, the number of readmissions per patient, and the number of patients with at least one readmission. These five comorbidities were history of myocardial infarction (MI), chronic pulmonary disease, obesity, congestive heart failure (CHF), and hypertension. Adjusted analysis of the number of patients with at least one readmission was conducted using a conditional logistic regression via the clogit function. Adjusted analysis of the length of stay and the number of readmissions per patient was analyzed using generalized estimating equations via the geeglm function, with family = gaussian (link = “identity”) and corstr = “exchangeable”.^18,19 Patients without paraplegia were the reference category for all of the adjusted analysis. Finally, in order to assess whether the cleaning process and control matching significantly changed the overall comorbidity profile of the patients who received an RCR, the final group of patients with paraplegia used in our analysis (n = 194) was compared to a larger sample of patients with paraplegia from the uncleaned database (n = 243). Likewise, the prevalence of comorbidities in the patients without paraplegia in our analysis (n = 194) was compared to the prevalence of comorbidities in patients without paraplegia in the uncleaned database (n = 33,965). The Chi-squared test with the Yates continuity correction, and the Fisher’s Exact test where appropriate, was used to compare the prevalence of comorbidities in the original database versus the cleaned and matched database within our study. A p-value of less than 0.05 was considered statistically significant.

Results

There were no significant differences in demographics between the two groups (Table 1). Comorbidity profiles were relatively similar between patients with and without paraplegia (Table 2). Patients with paraplegia had lower rates of chronic pulmonary disease (10.3% vs. 20.1%, p = 0.02), hypertension (50% vs. 63.9%, p = 0.007), CHF (2.1% vs. 5.2%, p = 0.027), obesity (9.3% vs. 22.7%, p < 0.001), and prior MI (2.1% vs. 8.2%, p = 0.01). There was no difference in the proportion of patients that had a urinary catheter or vascular access/infusion device placed between the two groups (Table 2). Regarding complications, only the rates of urinary tract infections (UTIs) and acute respiratory distress syndrome (ARDS) were significantly different between patients with paraplegia and patients without paraplegia (Table 3). Patients with paraplegia experienced a higher rate of UTIs (11.9% vs. 2.1%, p < 0.001) and a lower rate of ARDS (0% vs. 3.1%, p = 0.041).

Table 1.

Demographic data for the matched pairs composed of patients with and without paraplegia.

Demographic factors^a	RCR patients with paraplegia (n = 194)	RCR patients without paraplegia (n = 194)	Matched pair has outcome^c (n = 194 pairs)	p-Value
Age (Average years ± Standard deviation)	55.7 ± 9.3	55.6 ± 9.3
Females	47	47
Primary expected payer
Medicare	110	110
Medicaid	4	4
Private insurance	67	67
Other	13	13
Median household income of patient’s zipcode
0–25th percentile	42	42
26–50th percentile	43	43
51–75th percentile	53	53
76–100th percentile	56	56
Home state is the same as hospital state	188	186	179	1
Died during hospitalization^b	0	0	0	1
Quarter of hospitalization
January–March	57	57
April–June	42	42
July–September	50	50
October–December	45	45

Comparisons were made using McNemar’s test.

Initial hospitalization of interest when the RCR was performed.

Matched pair refers to the pair created by matching demographic factors (age (fuzzy factor of 3), sex, discharge quarter, their primary expected payer, and the median household income of the patients’ zip codes) of patients with paraplegia to patients without paraplegia. Both patients within the pair must have the demographic factors to be reported in this column.

RCR: rotator cuff repair.

Table 2.

Preoperative comorbidities and additional procedures that may impact outcomes for patients with and without paraplegia who underwent a rotator cuff repair.

Comorbidities^a	RCR patients with paraplegia (n = 194)	RCR patients without paraplegia (n = 194)	Matched pair has comorbidity^c (n = 194 pairs)	p-Value
AIDS	0 (0%)	1 (0.5%)	0 (0%)	1
Alcohol abuse	0 (0%)	5 (2.6%)	0 (0%)	0.074
Chronic pulmonary disease	20 (10.3%)	39 (20.1%)	2 (1.0%)	0.02
Diabetes, uncomplicated	24 (12.4%)	38 (19.6%)	3 (1.6%)	0.08
Liver disease	1 (0.5%)	4 (2.1%)	0 (0%)	0.371
Rheumatoid arthritis/Collagen vascular diseases	0 (0%)	5 (2.6%)	0 (0%)	0.074
Hypertension (complicated and uncomplicated)	97 (50.0%)	124 (63.9%)	64 (33.0%)	0.007
Metastatic cancer	0 (0%)	1 (0.5%)	0 (0%)	1
Valvular disease	2 (1.0%)	8 (4.1%)	0 (0%)	0.114
Diabetes, chronic complications	3 (1.5%)	10 (5.2%)	0 (0%)	0.1
Deficiency anemia	20 (10.3%)	11 (5.7%)	3 (1.5%)	0.1
Chronic blood loss anemia	0 (0%)	0 (0%)	0 (0%)	1
Congestive heart failure	4 (2.1%)	10 (5.2%)	1 (0.5%)	0.027
Coagulopathy	2 (1.0%)	3 (1.5%)	0 (0%)	1
Depression	32 (16.5%)	37 (19.1%)	7 (3.6%)	0.410
Hypothyroidism	12 (6.2%)	17 (8.8%)	1 (0.5%)	0.571
Fluid and electrolytes disorders	12 (6.2%)	14 (7.2%)	1 (0.5%)	0.8
Obesity^b	18 (9.3%)	44 (22.7%)	4 (2.1%)	<0.001
Pulmonary circulation disorders	0 (0%)	0 (0%)	0 (0%)	1
Renal failure	4 (2.1%)	11 (5.7%)	0 (0%)	0.1
Peptic ulcer disease, excluding bleeding	0 (0%)	0 (0%)	0 (0%)	1
Drug abuse	7 (3.6%)	7 (3.6%)	1 (0.5%)	1
Lymphoma	0 (0%)	0 (0%)	0 (0%)	1
Neurological disorders	8 (4.1%)	16 (8.2%)	1 (0.5%)	0.136
Peripheral vascular disorders	3 (1.5%)	4 (2.1%)	0 (0%)	1
Old myocardial infarction	4 (2.1%)	15 (8.2%)	0 (0%)	0.01
Procedures other than the rotator cuff repair that may impact outcomes
Insertion of urinary catheter	2 (1.0%)	0 (0%)	0 (0%)	0.5
Venous/Cardiac catheter, infusion, and/or vascular access device	9 (4.6%)	9 (4.6%)	1 (0.5%)	1

Bolded p-values show statistically significant differences in outcomes.

Comparisons were made using McNemar’s test. ^bDefined by an ICD-10 diagnosis code of E66.0, E66.01, E66.09, E66.1, E66.2, E66.3, E66.8, or E66.9.

AIDS: acquired immunodeficiency syndrome; RCR: rotator cuff repair.

Table 3.

Comparing the outcomes experienced by patients with paraplegia versus patients without paraplegia from a matched pair sample using McNemar’s test.

Complications	RCR patients with paraplegia (n = 194)	RCR patients without paraplegia (n = 194)	Matched pair has complication^c (n = 194 pairs)	p-Value
Bleeding	0 (0%)	2 (1.0%)	0 (0%)	0.480
Cardiac	0 (0%)	4 (2.1%)	0 (0%)	0.134
Central nervous system	0 (0%)	0 (0%)	0 (0%)	1
Gastrointestinal	1 (0.5%)	1 (0.5%)	0 (0%)	1
Acute renal failure	4 (2.1%)	4 (2.1%)	0 (0%)	1
Urinary tract infection	23 (11.9%)	4 (2.1%)	0 (0%)	<0.001
Infection	1 (0.5%)	1 (0.5%)	0 (0%)	1
Perivascular	0 (0%)	0 (0%)	0 (0%)	1
Shock	0 (0%)	0 (0%)	0 (0%)	1
Respiratory	1 (0.5%)	2 (1.0%)	0 (0%)	1
Wound	1 (0.5%)	1 (0.5%)	0 (0%)	1
Transfusion	0 (0%)	1 (0.5%)	0 (0%)	1
Debridement	0 (0%)	0 (0%)	0 (0%)	1
Cellulitis	2 (1.0%)	0 (0%)	0 (0%)	0.480
PE	0 (0%)	0 (0%)	0 (0%)	1
Pneumonia	4 (2.1%)	6 (3.1%)	0 (0%)	0.752
Acute respiratory distress syndrome	0 (0%)	6 (3.1%)	0 (0%)	0.041
Sepsis	1 (0.5%)	1 (0.5%)	0 (0%)	1
Thrombosis	0 (0%)	0 (0%)	0 (0%)	1
Any of the above complications	33 (19.6%)	25 (17.0%)	5 (2.6%)	0.4
RCR in follow-up^a	5 (2.6%)	2 (1.0%)	0 (0%)	0.450
TSA in follow-up^a	0 (0%)	1 (0.5%)	0 (0%)	1
Patients with readmissions^a,b	40 (20.6%)	37 (19.1%)	10 (5.2%)	0.8

Bolded p-values show statistically significant differences in outcomes.

Data were from follow-up admissions after the RCR.

At least one readmission, for any reason, following the RCR of interest.

PE: pulmonary embolism; RCR: rotator cuff repair; TSA: total shoulder arthroplasty.

A comparison of the proportion of patients discharged to various post-operative management types is shown in Table 4. We found that patients with paraplegia were significantly less likely to be discharged to home care (p < 0.001) and were more likely to be transferred to a skilled nursing facility, intermediate care facility, or another type of facility (p < 0.001) compared to able-bodied matched controls. The median length of stay was longer for patients with paraplegia (4 days vs. 1 day, p < 0.001), while the number of readmissions per patient between the two groups was similar (Table 5). After adjusting for potential confounding comorbidities (Table 6), the length of stay was still significantly longer for patients with paraplegia (p < 0.001); however, the average number of readmissions and being readmitted at least once were not significantly different between the two groups (p = 0.076 and p = 0.328, respectively). Comorbidity profiles were analyzed to compare differences between our case-matched sample and the larger population undergoing RCR provided by the NRD (Table 7). There were no significant differences between our cohort and the original group of patients with paraplegia who received an RCR in the NRD. There was a significantly greater prevalence of depression (19.1% vs. 13.3%, p = 0.02), drug abuse (3.6% vs. 1.5%, p = 0.03), and old MI (8.2% vs. 4.1%, p = 0.02) in our control cohort compared to patients with paraplegia who underwent an RCR in the NRD.

Table 4.

Comparing the discharge location for each patient.

Discharge location	RCR patients with paraplegia (n = 194)	RCR patients without paraplegia (n = 194)	Matched pair has complication^a (n = 194 pairs)	p-Value
Discharged to home or self-care	25 (13.0%)	147 (75.8%)	20 (10.3%)	<0.001
Transfer to short-term hospital	4 (2.1%)	0 (0%)	0 (0%)	0.1
Transfer to skilled nursing facility, intermediate care facility, or another type of facility	137 (71.0%)	21 (10.8%)	18 (9.3%)	<0.001
Home healthcare	26 (13.5%)	22 (11.3%)	2 (1.0%)	0.7
Left against medical advice	1 (0.5%)	4 (2.1%)	0 (0%)	0.4

Bolded p-values show statistically significant differences in outcomes.

RCR: rotator cuff repair.

Table 5.

Comparing the length of stay for the original hospitalization of interest and the average number of readmissions per patient using the Wilcoxon signed-rank test.

	RCR patients with paraplegia				RCR patients without paraplegia				p-Value
	Min-Max	Median	IQR	Mean	Min-Max	Median	IQR	Mean	p-Value
Length of stay	0–95	4	3.3	7.1	0–29	1	2	2.5	<0.001
Number of readmissions per patient	0–7	0	0	0.37	0–4	0	0	0.28	0.4

Bolded p-value shows statistically significant differences.

IQR: inter-quartile range; RCR: rotator cuff repair.

Table 6.

Accounting for potential confounding comorbidities when evaluating the number of patients with readmissions, the average number of readmissions per patient, and the length of stay.

	β	Standard error (β)	Odds ratio	95% Confidence interval		p-Value
	β	Standard error (β)	Odds ratio	Lower	Upper	p-Value
Patients with readmissions^a,b	0.306	0.313	1.36	0.736	2.51	0.328
Average number of readmissions per patient^c	0.163	0.092	–	–	–	0.076
Length of stay^c	4.54	0.894	–	–	–	<0.001

Bolded p-value shows statistically significant results.

Patients without paraplegia were the reference category, and the comorbidities included in the adjusted analysis were history of myocardial infarction, obesity, congestive heart failure, and hypertension.

At least one readmission, for any reason, following the RCR of interest.

Conditional logistic regression was run.

Generalized estimating equations was run.

RCR: rotator cuff repair.

Table 7.

Comparing the comorbidity profiles of our two sample groups to larger patient samples from the same database.

Comorbidities	Patients with paraplegia sample (n = 194)	Patients with paraplegia (n = 243)	p-Value	Patients without paraplegia sample (n = 194)	Patients without paraplegia (n = 33,965)	p-Value
AIDS	0 (0%)	0 (0%)	–	1 (0.5%)	30 (0.1%)	0.2
Alcohol abuse	0 (0%)	0 (0%)	–	5 (2.6%)	876 (2.6%)	1
Chronic pulmonary disease	20 (10.3%)	27 (11%)	0.9	39 (20.1%)	6,772 (19.9%)	1
Diabetes, uncomplicated	24 (12.4%)	36 (14.8%)	0.6	38 (19.6%)	7,133 (21.0%)	0.7
Liver disease	1 (0.5%)	3 (1.2%)	0.6	4 (2.1%)	629 (1.9%)	0.8
Rheumatoid arthritis/ Collagen vascular diseases	0 (0%)	2 (0.8%)	0.5	5 (2.6%)	1,358 (4.0%)	0.4
Hypertension (complicated and uncomplicated%)	97 (50.0%)	117 (48.1%)	0.8	124 (63.9%)	21,035 (61.9%)	0.6
Metastatic cancer	0 (0%)	1 (0.4%)	1	1 (0.5%)	242 (0.7%)	1
Valvular disease	2 (1.0%)	3 (1.2%)	1	8 (4.1%)	1,403 (4.1%)	1
Diabetes, chronic complications	3 (1.5%)	3 (1.2%)	1	10 (5.2%)	1,421 (4.2%)	0.6
Deficiency anemia	20 (10.3%)	27 (11.1%)	0.9	11 (5.7%)	2,988 (8.8%)	0.2
Chronic blood loss anemia	0 (0%)	0 (0%)	–	0 (0%)	184 (0.5%)	0.6
Congestive heart failure	4 (2.1%)	6 (2.5%)	1	10 (5.2%)	1,759 (5.2%)	1
Coagulopathy	2 (1.0%)	2 (0.8%)	1	3 (1.5%)	748 (2.2%)	0.8
Depression	32 (16.5%)	38 (15.6%)	0.9	37 (19.1%)	4,514 (13.3%)	0.02
Hypothyroidism	12 (6.2%)	18 (7.4%)	0.7	17 (8.8%)	4,724 (13.9%)	0.05
Fluid and electrolytes disorders	12 (6.2%)	18 (7.4%)	0.7	14 (7.2%)	3,224 (9.5%)	0.3
Obesity	18 (9.3%)	21 (8.6%)	0.9	44 (22.7%)	5,946 (17.5%)	0.07
Pulmonary circulation disorders	0 (0%)	0 (0%)	–	0 (0%)	371 (1.1%)	0.3
Renal failure	4 (2.1%)	6 (2.5%)	1	11 (5.7%)	2,029 (6.0%)	1
Peptic ulcer disease, excluding bleeding	0 (0%)	0 (0%)	–	0 (0%)	41 (0.1%)	1
Drug abuse	7 (3.6%)	8 (3.3%)	1	7 (3.6%)	496 (1.5%)	0.03
Lymphoma	0 (0%)	0 (0%)	–	0 (0%)	231 (0.7%)	0.6
Neurological disorders	8 (4.1%)	12 (4.9%)	0.9	16 (8.2%)	2,334 (6.9%)	0.5
Peripheral vascular disorders	3 (1.5%)	4 (1.6%)	1	4 (2.1%)	977 (2.9%)	0.6
Old myocardial infarction	4 (2.1%)	8 (3.3%)	0.6	15 (8.2%)	1,414 (4.1%)	0.02

Bolded p-values show statistically significant results.

AIDS: acquired immunodeficiency syndrome.

Discussion

Chronic, debilitating shoulder pain and tears of the rotator cuff muscles are common in individuals with paraplegia due to the over-use associated with wheelchair mobility and transfers. When conservative treatment fails to adequately manage this pain and pathology, these patients often undergo surgery, such as RCR. Although surgical intervention is a common treatment strategy for these patients, a comprehensive analysis of the specific adverse perioperative outcomes associated with RCR in this population is currently lacking. The data presented in this study demonstrate that patients with paraplegia undergoing RCR often experience a significantly longer median hospital stay yet have a favorable comorbidity profile and are not at an increased risk of developing most perioperative complications except for UTIs.

The majority of the comorbidities included in our analysis were observed in similar proportions in patients with and without paraplegia; however, we did find that patients with paraplegia are significantly less likely to have the following comorbid conditions: chronic pulmonary disease (p = 0.015), hypertension (p = 0.004), CHF (p = 0.027), and obesity (p < 0.001). Additionally, we did not find any single comorbidity to be more highly represented in patients with paraplegia compared to controls. One possible explanation for this finding is that the presence or absence of comorbidities influenced determination of surgical candidacy. This could be done in an attempt to minimize postoperative complications in this at-risk population because the presence of numerous comorbidities is associated with at least one complication following RCR, as well as high rates of unplanned re-admissions.²⁰ Additionally, obesity has been found to correlate with increased RCR revision rates.²¹ To ensure that the differences observed in the comorbidity profiles between the two groups were not due to our sample selection process, we compared the comorbidities of our sample patients to larger samples pulled from the NRD. Overall, the comorbidity profiles of our cohorts were relatively similar to those of the uncleaned database.

Comparison of the complication rates observed in both patient groups shows that the only perioperative complication that patients with paraplegia were at an increased risk for was developing an UTI. Nearly 12% of the patients with paraplegia included in our analysis developed an UTI, compared to only 1.5% of controls (p < 0.001). While UTIs are of the most common causes of morbidity in patients with paraplegia,^22,23 this observation underscores the importance of careful post-operative management for patients with paraplegic following RCR as they already have an intrinsic risk of developing these infections. Additionally, our evaluation of the presence of urinary catheters showed no significant difference between those with paraplegia and those without, demonstrating that urinary catheters used post-operatively are not the sole contributor to the increased prevalence of UTIs in patients with paraplegia.

The other complication that was significantly different between patients with and without paraplegia was ARDS, which was observed at a higher rate in the control group (p = 0.027). Despite the lower rate of ARDS in patients with paraplegia, this association likely is not related to functional status. ARDS can be caused by a number of events including trauma and surgery, and it is possible that the increased incidence of this complication in the control group is attributable to the high proportion of patients with pre-existing pulmonary disease as chronic obstructive pulmonary disease is a predictor of ARDS and lung complications following surgery.^24,25 Because of this association, it is important to confirm pulmonary stability prior to surgery and to ensure the patient is not experiencing an exacerbation.

The presence of a more favorable comorbidity profile and low complication rates in patients with paraplegia relative to able-bodied controls was an unexpected finding. This could be explained by the overall good health of the patients included in our paraplegic sample as is reflected by the significantly lower proportion of obese patients in this group. There is a known relationship between obesity and many comorbid conditions such as diabetes, hypertension, and heart disease,²⁶ which explains the less favorable comorbidity profile we observed in our control group because these patients were significantly more obese. Furthermore, it has been documented that the presence of comorbidities increases the risk of experiencing at least one complication following RCR,²⁰ and this explains the higher rate of complications we observed in our control group.

In addition to medical complications, we evaluated the proportion of patients that experienced a re-tear of the repaired rotator cuff. Factors associated with increased rates of cuff re-tear are patient age,²⁷ size of the initial tear, and supraspinatus fatty degeneration, and should therefore be considered when determining treatment strategy.²⁸ Despite rotator cuff re-tears being a common occurrence, they are not necessarily associated with unfavorable clinical outcomes. Patients often have satisfactory functional outcomes and reductions in shoulder pain despite the re-tear.^29,30 Although the reported rate of re-tears after surgery in patients with paraplegia is comparable to that of able-bodied individuals, 11%–25%^9–11 versus 7%–69%,^28,31,32 respectively, the implications of a re-tear of the rotator cuff are likely different for the two patient populations. While there is no standardized management strategy for re-tears, revision surgeries are an option for patients with symptomatic re-tears who experience persistent pain and loss of function. However, in addition to the considerable burden that a second surgery would place on a patient with paraplegia, previous studies show that a revision RCR is twice as likely to re-tear compared to the primary RCR.^33–35

Previous studies of patients with paraplegia undergoing RCR have reported re-tears rates ranging from 11% to 25% and structural failure rates as high as 33%.^9–11 Because of this, we expected to see a higher rate or re-tears in our sample of patients with paraplegia compared to our controls. To evaluate this in our sample, we looked at follow-up data for each patient and classified a re-tear or failure to heal as either the presence of an additional RCR procedure or the presence of a TSA in a subsequent visit. While our data showed that the proportion of patients with an additional RCR procedure in a follow-up visit was higher in patients with paraplegia, the difference was not statistically significant. Similarly, there was no difference in the proportion of patients receiving a TSA in a subsequent visit following the primary RCR between the two groups. Although our data did not reflect a higher rate of re-tears in patients with paraplegia, this could be due to limitations of the dataset used for this study. The NRD only contains follow-up data through each individual calendar year, and while the dataset provides substantial follow-up data to assess short-term complications, it limits evaluation of events that could occur in the years following surgery such as a re-tear or revision procedure.

We evaluated the differences in the length of stay between the two groups. Our data showed that patients with paraplegia experienced a median hospital stay of 4 days while their able-bodied counterparts had a median stay of 1 day (p < 0.001). We also assessed the different types of post-operative management strategies used for patients with paraplegia compared to controls and found that patients with paraplegia were significantly more likely to be transferred to a long-term care facility. These findings are consistent with previous reports of patients with paraplegia remaining in the hospital or long-term care facility for up to 10-weeks following RCR,^10,12 as opposed to be discharged to at-home care which we observed to occur at a much higher rate in our control group. The substantially longer length of stay required for patients with paraplegia is likely due to the compounded functional impairment that results from surgery on a weight-bearing shoulder.

Limitations

It is important to note that our study is not without limitations. The McNemar’s test with continuity correction was used to compare our two patient groups and it is possible that this test is overly conservative (i.e. it underestimates true differences and produces larger p-values).³⁶ Additionally, the dataset used for this study (the HCUP NRD) provides information only on patients who were hospitalized following their RCR procedure. Therefore, patients managed from home are not captured and this could impact reported data as hospitalized patients are intrinsically at a higher risk of complications following surgery. Lastly, as previously mentioned, this dataset only includes follow-up data through the calendar year in which the procedure took place. This causes complications or events that occurred in the following years to be not reported. Future work should aim to expand on the data presented in this study regarding re-tears of the rotator cuff, as well as readmission rates, as these events often occur outside of the NRD’s available follow-up.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Ethical Review and Patient Consent

Ethical approval and informed consent were not sought for the present study due to the use of a publicly available, de-identified database. This study was completed in accordance with the Helsinki Declaration as revised in 2013.

Guarantor

RF.

Contributorship

MB researched the literature and wrote the final draft of the manuscript. KO designed the methodology and led the data analysis. GN assisted in interpreting the results. BK compiled the data into a usable format. JE and RF conceived the study and oversaw the project to completion. All authors reviewed and edited the manuscript and approved the final version of the manuscript.

ORCID iD

Richard J Friedman

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