Carpal Tunnel Release Performed during Distal Radius Fracture Surgery

Abstract

Background  Carpal tunnel release (CTR) may be concomitantly performed along with distal radius fracture open reduction internal fixation (DRF ORIF) to prevent carpal tunnel syndrome; however, there is little to no literature investigating the rate, risk factors, and complications associated with CTR.

Questions/Purposes  The purpose was to determine (1) the rate of CTR performed at time of DRF ORIF, (2) factors associated with CTR, and (3) whether CTR was associated with any complications.

Patients and Methods  In this case-control study, adult patients who underwent DRF ORIF from 2014 to 2018 were identified from a national surgical database. Two cohorts were analyzed, (1) patients with CTR and (2) patients without CTR. Preoperative characteristics and postoperative complications were compared with determine factors associated with CTR.

Results  Of the 18,466 patients, 769 (4.2%) had CTR. Rates of CTR in patients with intra-articular fractures with two or three fragments were significantly higher than the rate of CTR for patients with extra-articular fractures. Underweight patients underwent CTR at a significantly lower rate compared with overweight and obese patients. The American Society of Anesthesiologists ≥3 was associated with a higher rate of CTR. Male and older patients were less likely to have CTR.

Conclusion  The rate of CTR at time of DRF ORIF was 4.2%. Intra-articular fractures with multiple fragments were strongly associated with CTR at time of DRF ORIF, while being underweight, elderly, and male were associated with lower rates of CTR. These findings should be considered when developing clinical guidelines to assess the need for CTR in patients undergoing DRF ORIF. This is a retrospective case control study and reflects level of evidence III.

Distal radial fractures (DRF) are common orthopaedic injuries accounting for approximately 15% of all fractures, and one-fifth of all fractures seen in the emergency department. ^{1 2 3 4 5 6} The recent emphasis on restoring normal anatomy to ensure good outcomes has led to an increase in operative management of these injuries. ^{7 8 9 10} Overall, the reported rate of complications arising from DRF ranges greatly from 6 to 80% ¹¹ and can include malunion, nonunion, complex regional pain syndrome (CRPS), and impaired wrist and finger motion. ^{12 13} Acute carpal tunnel syndrome (CTS), although uncommon, is a known complication resulting from DRF, ¹⁴ especially in high-energy cases resulting in soft tissue edema, hematoma, or volarly displaced fracture fragments that may compress or compromise the median nerve. ^{15 16 17 18 19 20}

The incidence of CTS after DRF has been previously reported up to 20%. ^{21 22} Carpal tunnel release (CTR) may also be performed prophylactically in patients with an increased likelihood of developing CTS after DRF, although there is a paucity of literature to guide surgeons as to when this may be indicated.

Thus, the aim of this large nationwide multicenter retrospective study is to determine (1) the rate of CTR performed at the time of DRF open reduction internal fixation (ORIF), (2) factors associated with CTR performed at the time of ORIF, and (3) whether having concomitantly performed CTR was associated with complications. We hypothesize that the rate of CTR performed concomitantly at time of DRF ORIF will be approximately 10%, obesity, and high-energy fracture patterns will increase the likelihood of CTR in DRF ORIF, and CTR would not be associated with an increased rate of complications.

Patients and Methods

This case-control study used the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database to extract all patients undergoing DRF ORIF as defined by the Current Procedural Terminology (CPT) codes 25607 (extra-articular), 25608 (intra-articular of two fragments), and 25609 (intra-articular of three or more fragments) between 2014 and 2018. Patients undergoing CTR for CTS were determined by CPT code 64721 (neuroplasty and/or transposition of median nerve at carpal tunnel). Only patients with CTR at the time of DRF ORIF were included. Patients with CTR performed as a separate procedure any time after DRF ORIF were not included as the ACS-NSQIP database only provides patient information from the first 30 days after the index procedure. No identifiable patient information was included in this public use database; therefore, this study was exempt from institutional review board approval.

The ACS-NSQIP database does not include the following as described by its case exclusion criteria: patients younger than 18 years of age, patients with incomplete or missing data, and patients admitted under the acute trauma pathway. ²³ This study excluded patients with both-bone forearm fractures.

Patients meeting the inclusion criteria were stratified into two groups based on whether CTR was performed at the time of DRF ORIF. Preoperative patient demographic factors (age, sex, body mass index [BMI], and fracture pattern) and comorbidities (the American Society of Anesthesiologists [ASA] class, hypertension, diabetes, pulmonary disease, cardiac disease, smoking, chronic steroid use, and functional status) were collected and compared between cohorts. Rates of postoperative complications, such as cardiopulmonary complications, wound complications, secondary infections, deep vein thrombosis, pulmonary embolism, renal impairment, stroke, readmission, and need for additional procedures, were compared between cohorts. Due to large sample size with data obtained from multiple institutions, normal distribution was assumed. Thus, the variable of operative time was reported as mean and standard deviation.

Multivariate logistic regression analyses were performed to determine factors contributing to CTR at the time of DRF ORIF. Statistical analysis was performed using the R statistical software package (R Foundation for Statistical Computing, Vienna, Austria). Student's t -test, Chi-squared contingency testing, and multivariate logistic regression were conducted. All variables were controlled for in a multivariable regression analysis to identify independent variables significantly associated with CTR. All individual complications were reported, with patients having more than one complication being counted only once in the “Any Complication” category. A p -value of <0.05 was deemed statistically significant.

Results

Of the 18,466 patients meeting inclusion criteria, 769 (4.2%) had CTR at the time of DRF ORIF ( Table 1 ).

Table 1. Preoperative patient characteristics, distal radius ORIF.

	Total	With CTR n (%)	Without CTR n (%)	p -Value
Total	18,466	769 (4.2)	17,697 (96)
Age (y)				0.130
< 50	5,392	237 (4.4)	5,155 (96)
50–69	9,235	394 (4.3)	8,841 (96)
≥70	3,839	138 (3.6)	3,701 (96)
Sex				0.349
Female	13,562	576 (4.2)	12,986 (96)
Male	4,904	193 (3.9)	4,711 (96)
Fracture Pattern				< 0.001
Extra-articular	6,861	197 (2.9)	6,664 (97)
Intra-articular, two fragments	5,827	214 (3.7)	5,613 (96)
Intra-articular, >3 fragments	5,778	358 (6.2)	5,420 (94)
Open fracture	452	19 (4.2)	433 (96)	0.966
Obesity class (kg/m 2 )				0.015
Normal (18.5–24.9)	5,777	249 (4.3)	5,528 (96)
Underweight (<18.5)	363	7 (1.9)	356 (98)
Overweight (25–29.9)	5,813	223 (3.8)	5,590 (96)
Obese class I (30–34.9)	3,338	172 (5.2)	3,166 (95)
Obese class II (35–39.9)	1,363	58 (4.3)	1,305 (96)
Obese class III (40 + )	1,053	48 (4.6)	1,005 (95)
ASA class				0.005
1–2	13,549	531 (3.9)	13,018 (96)
≥3	4,894	238 (4.9)	4,656 (95)
Hypertension	5,959	256 (4.3)	5,703 (96)	0.537
History of diabetes	1,542	76 (4.9)	1,466 (95)	0.117
History of pulmonary disease	978	40 (4.1)	938 (96)	0.905
History of cardiac disease	63	0 (0)	63 (100)	0.097
History of smoking	3,480	161 (4.6)	3,319 (95)	0.130
Chronic steroid use	371	22 (5.9)	349 (94)	0.086
Nonindependent functional status	281	14 (5)	267 (95)	0.464

Abbreviations: ASA, American Society of Anesthesiologists; CTR, carpal tunnel release; ORIF, open reduction internal fixation.

The rates of CTR for patients with intra-articular fractures with three or more fragments (6.2%) or two fragments (3.7%) were significantly higher than the rate of CTR for patients with extra-articular fractures (2.9%; p  < 0.001). Underweight patients underwent CTR at a significantly lower rate (1.9%) compared with patients who are of normal weight (4.3%), overweight (3.8%), or obese (4.8%; p  = 0.015). ASA class of ≥3 (4.9%) was associated with a higher rate of CTR than that in patients with an ASA of 1 or 2 (3.9%; p  = 0.005). Other preoperative patient demographics and comorbidities were similar between cohorts. There was no significant difference between rate of CTR at the time of DRF ORIF for open fractures (19/452, 4.2%) compared with closed fractures (750/18,014, 4.2%; p  = 0.97; Table 1 ). A multivariate analysis was then performed to identify potential factors associated with CTR at the time of DRF ORIF. When compared with extra-articular fractures, intra-articular fractures with two fragments (odds ratio [OR]: 1.29, 95% confidence interval [CI]: 1.06–1.58, p  = 0.012) and intra-articular fractures with three fragments (OR = 2.14, 95% CI: 1.78–2.57, p  < 0.001) were more likely to require CTR. Patients with an ASA ≥3 were more likely to undergo CTR than patients with an ASA of 1 or 2 (OR = 1.36, 95% CI: 1.12–1.65, p  = 0.002). Patient factors associated with lower likelihood of CTR included older age (≥70years; OR = 0.72, 95% CI: 0.56–0.94, p  = 0.016), being underweight (OR = 0.38, 95% CI: 0.17–0.85, p  = 0.019), and male sex (OR = 0.82, 95% CI: 0.68–0.99, p  = 0.035; Table 2 ).

Table 2. Results of multivariate analyses for risk factors associated with CTR.

Outcome/risk factor	Adjusted odds ratio (95% confidence interval)	p -Value
Age: reference ≤50 (y)
50–69	0.93 (0.77, 1.12)	0.451
≥70	0.72 (0.56, 0.94)	0.016
Sex: male vs. female	0.82 (0.68, 0.99)	0.035
Fracture pattern: reference = extra-articular
Intra-articular, two fragments	1.29 (1.06, 1.58)	0.012
Intra-articular, 3+ fragments	2.14 (1.78, 2.57)	<0.001
Fracture: open vs. closed	0.99 (0.61, 1.63)	0.982
BMI (kg/m 2 ): reference. = normal (18.5–24)
Underweight (<18.5)	0.38 (0.17, 0.85)	0.019
Overweight (25–29)	0.87 (0.72, 1.05)	0.134
Obese class I (30–34)	1.15 (0.93, 1.41)	0.190
Obese class II (35–40)	0.85 (0.62,1.15)	0.288
Obese class III (40 + )	0.84 (0.6, 1.18)	0.328
ASA rating: ≥3 vs. 1–2	1.36 (1.12, 1.65)	0.002
Hypertension	0.99 (0.82, 1.19)	0.915
Diabetes	1.07 (0.82, 1.39)	0.635
History of COPD	0.89 (0.63, 1.25)	0.485
Smoking	1.12 (0.93, 1.35)	0.245
Steroid use	1.44 (0.92, 2.24)	0.112
Nonindependent functional status	1.13 (0.65, 1.96)	0.674

Abbreviations: ASA, American Society of Anesthesiology score; BMI, body mass index; COPD, chronic obstructive pulmonary disease; CTR, carpal tunnel release.

Mean operative time for DRF ORIF requiring CTR was greater than the operative time for DRF ORIF without CTR (89.5 vs. 75.9 minutes, p  < 0.001). Postoperative complications were similar between cohorts ( Table 3 ).

Table 3. Thirty-day postoperative complications after distal radius ORIF.

	Total ( n )	With carpal tunnel release n (%)	Without carpal tunnel release n (%)	p -Value
Total	18,466	769	17,697
Any complication	376	21 (5.6)	355 (94)	0.164
Major complications	230	9 (3.9)	221 (96)	0.848
Death	26	0	26	0.287
Sepsis	14	0	14	0.435
Septic shock	6	1	5	0.125
Deep SSI	13	0	13	0.452
Wound dehiscence	7	1	6	0.180
Pulmonary embolism	4	0	4	0.677
Ventilator >48 hours	7	0	7	0.581
Unplanned intubation	12	1	11	0.470
Acute renal failure	1	0	1	0.835
Cardiac arrest requiring CPR	6	0	6	0.610
Myocardial infarction	7	0	7	0.581
Stroke	9	0	9	0.532
Return to operating room	168	7 (4.2)	161 (96)	0.999
Minor complications	173	12 (6.9)	161 (93)	0.067
Superficial SSI	38	2	36	0.734
Pneumonia	29	1	28	0.847
Urinary tract Infection	63	4 (6.3)	59 (94)	0.385
DVT or thrombophlebitis	8	0	8	0.555
Transfusion	35	5	30	0.003
Renal insufficiency	7	1	6	0.180
Unplanned readmission	272	13 (4.8)	259 (95)	0.609
Operative time (min) Mean (SD; range)	76.5 (39.4; 352)	89.5 (48.3; 345)	75.9 (38.8; 352)	< 0.001

Abbreviations: CPR, cardiopulmonary resuscitation; DVT, deep venous thrombosis; ORIF, open reduction internal fixation; SD, standard deviation; SSI, surgical site infection.

Discussion

CTR may be concomitantly performed along with DRF ORIF to prevent CTS; however, there is little to no literature investigating the rate, risk factors, and complications associated with CTR. In this large database analysis of 18,466 patients, the rate of CTR in DRF ORIF was 4.2%. Factors associated with increased rates of CTR at the time of DRF included intra-articular fractures with multiple fragments, younger age, and an ASA level ≥3, while being underweight and male were associated with lower rates of CTR. Operative time for procedures with CTR were on average 13.6 minutes longer than those without CTR. There were no significant differences in preoperative patient comorbidities or 30-day postoperative complications between the two cohorts.

This study is limited by its retrospective nature and the limited scope of what questions the ACS-NSQIP can answer. Some complications specific to DRF that occur after 30 days (e.g., long-term progressive median nerve injury, nonunion, malunion, CRPS, peri-implant fracture or implant failure, and tendon rupture) and functional outcomes (e.g., impaired wrist and finger motion) were not included in the database, yet have the potential to influence the decision if CTR should be performed. Furthermore, CTR at the time of DRF ORIF is at the discretion of the surgeon, and individual patient symptoms, operative findings describing indication for performing CTR, and confirmatory studies, such as electromyography findings or nerve conduction studies, were not available. In addition, it is unknown which patients in this study might have been experiencing CTS symptoms prior to their injury and this information could have provided reasons for associations between some of the factors associated with increased rate of CTR. ACS-NSQIP does not provide radiographic imaging to analyze fracture fragment displacement which has been reported to be an important risk factor for developing CTS. ²¹ This study did not analyze association between patient characteristics and fracture pattern which could have provided further information about the reason for higher rate of CTR in certain groups if they were also more likely to have higher energy fracture patterns. ACS-NSQIP does not provide duration between initial injury and time of surgery and also does not provide information on the training background of who performed the surgery. However, because all CTR procedures were performed concurrently with DRF ORIF, this would likely suggest an acute to subacute presentation of symptoms. In the future, a multicentered study that includes long-term outcomes and provides the stated surgical reason for CTR may provide more substantial evidence for associated risk factors.

It is important to have a better understanding of how commonly CTR is performed in patients with a DRF, as failure to intervene on acute CTS can result in permanent median nerve damage, leading to loss of thenar muscle function, decreased hand dexterity, diminished sensation, and severe pain. ^{24 25 26} The incidence of CTS after DRF has been previously reported up to 20%. ^{21 22} However, to our knowledge, there is little to no literature investigating the rates of the CTR procedure in patients with a DRF.

Previous studies have demonstrated a correlation between higher energy injury patterns and acute CTS. Itsubo et al showed that 68% of patients with acute-onset CTS after DRF (defined as within 1 week after fracture) sustained fractures compared with the subacute onset (1–12 weeks after fracture) group with 79% A-type fractures and the delayed onset (>12 weeks after fracture) group with 63% A-type fractures. ²⁷ Dyer et al found a statistically significant difference in the amount of fracture fragment translation between patients requiring CTR at the time of DRF ORIF compared with patients who did not require CTR. ²¹ Earp et al determined the rate of simultaneous CTR with DRF ORIF to be 10.7% ²² and found that among patients undergoing concurrent CTR and DRF ORIF, having a surgery after the injury but before DRF ORIF, open fractures, and AO C-type fractures were statistically significant risk factors. Furthermore, they showed that of patients undergoing simultaneous CTR and DRF ORIF, 76% had preoperative median nerve paresthesia and 61% had a preinjury diagnosis of CTS. Our study also found higher energy fractures to be associated with a higher rate of undergoing CTR but found that open fractures were not significantly associated with, nor a risk factor for CTR at the time of DRF ORIF.

There are many established risk factors for developing atraumatic CTS including female sex, older age, obesity, diabetes, hypothyroidism, rheumatoid arthritis, renal failure, and pregnancy (Ekman-Ordeberg et al, Michelsen and Posner, Mondelli et al, and Stevens et al). ^{28 29 30 31} However, few studies have attempted to identify patient characteristics and comorbidities that could be risk factors for requiring CTR for acute CTS due to trauma. Itsubo et al showed that patients with acute-onset CTS after DRF were younger (average age: 49 years) compared with patients with subacute or delayed CTS (average age: 63.6 and 64.3 years, respectively). ²⁷ The proportion of males was significantly higher in the acute onset CTS group compared with the other two groups. Males in the study by Itsubo et al were 2.63 times more likely to undergo CTR at the time of DRF ORIF; however, this was not statistically significant. Our study also showed that older age was associated with lower rates of CTR at the time of DRF ORIF. Yeh et al reported that diabetes mellitus was a significant risk factor for CTS within 9 months after DRF. ³² Diabetes was not a significant indicator in this analysis, with rate of CTR at the time of DRF ORIF being 9.9 versus 8.3% ( p  = 0.117) in nondiabetic patients (OR = 1.07, 95% CI: 0.82–1.39, p  = 0.635). Interestingly, our study found that an underweight BMI was associated with lower rates of CTR. Although obesity has been described as a risk factor for atraumatic CTS, no studies have commented on the role of a patient's BMI in the likelihood of developing acute CTS after DRF.

Acute CTS, when missed, can have detrimental complications. Physical examination alone has been reported to serve as a poor predictor of CTS, and use of nerve conduction tests in conjunction with clinical examination may provide more objective criteria for performing CTR. ^{33 34} In contrast, unnecessary CTR may expose the patient to additional complications including iatrogenic median nerve injury. Odumala et al found that among patients who underwent DRF ORIF, patients who also had a CTR were two times more likely to have postoperative median nerve dysfunction; however, this result was not statistically significant, and the CTR group only consisted of 24 patients. ³⁵ Chauhan et al compared patient-reported outcomes between patients who had CTR at the time of DRF ORIF and those who had only elective CTR performed, and there found no statistically significant difference in the Boston Carpal Tunnel Questionnaire Scores between groups. ¹⁶ These studies suggest that CTR at the time of DRF may not clearly benefit the patient. It is therefore essential to identify which patients would benefit most from CTR at the time of DRF ORIF and more studies are needed to aid surgeons in careful patient selection.

Conclusions

Despite the limitations mentioned, important conclusions can be obtained from this study. ACS-NSQIP provides high-quality, validated data, and a large sample size from multiple centers, making our study significantly more powered than previous studies looking at CTR at the time of DRF ORIF. We were able to determine the overall incidence rate of CTR at the time of DRF ORIF, as well as factors associated with increased, and decreased, rates of CTR on a national scale. While no single factor should direct CTR in the setting of DRF aside from clinical findings, certain factors studied in this paper should raise clinical suspicion of acute CTS. Our results may inform clinicians and support clinical guidelines that may more accurately predict concomitant CTR associated with DRF ORIF. The risk factors described may assist surgeons in counseling patients regarding the need for CTR.

Funding Statement

Funding The authors received no financial support for the research, authorship, and/or publication of this article.