Predictors of functional outcomes after simple decompression for ulnar neuropathy at the elbow: a multicenter study by the SUN study group

Electrodiagnostic severity does not predict short- to midterm outcomes of cubital tunnel release surgery

HYPOTHESIS

This study aimed to explore the prognostic value of electrodiagnostic studies (EDS) to clarify their utility in clinical practice prior to cubital tunnel release surgery and to identify patient factors associated with patient-reported functional improvement after surgery. Our hypothesis was that patients with severe preoperative findings on EDS will tend to experience less functional improvement after surgery given the extent of ulnar nerve compressive injury.

METHODS

Patients with cubital tunnel syndrome and preoperative electrodiagnostic data treated from 2012 to 2022 with cubital tunnel release were assessed regarding demographic information, preoperative physical examination findings, EDS findings, postoperative complications, and patient-reported outcomes. Short- to midterm quick Disabilities of the Arm, Shoulder, and Hand questionnaire (qDASH) scores were collected for all patients for further evaluation of preoperative EDS data. Patients were grouped into those who had met the minimal clinically important difference (MCID) in delta qDASH at short- to midterm follow-up and those who did not. EDS data included sensory nerve onset latency, peak latency, amplitude, conduction velocity, as well as motor nerve latency, velocity, and amplitude. Electromyographic (EMG) studies were also reviewed, which included data pertaining to fibrillations, presence of abnormal fasciculation, positive sharp waves, variation in insertional activity, motor unit activity, duration of activity, and presence of increasing polymorphisms.

RESULTS

Of the 257 patients included, 160 (62.0%) were found to meet the MCID for short- to midterm qDASH scores. There were no significant differences between patients who did or did not meet the MCID regarding baseline demographics, comorbidities, preoperative examination findings, and operative technique. Patients who met MCID tended to have lower complication (3.80% vs. 7.20%, P = .248) and revision (0.60% vs. 4.10%, P = .069) rates, but these findings were not statistically significant. The cubital tunnel severity as determined by the EDS was similar between cohorts (14.1% vs. 14.3%, P = .498). Analysis of EMG testing showed there were no significant differences in preoperative, short- to midterm qDASH, or delta short- to midterm qDASH scores for patients with or without abnormal EMG findings. Multivariate regression suggested that only age (P = .003) was associated with larger delta qDASH scores.

CONCLUSION

Patient-reported preoperative disease severity may predict the expected postoperative change in ulnar nerve functional improvement, and EDS may not have prognostic value for patients undergoing cubital tunnel decompression. Therefore, physicians may suggest surgical treatment without positive EDS findings and still expect postoperative improvement in functional outcomes.

Electrodiagnostic Predictors of Outcomes After In Situ Decompression of the Ulnar Nerve

PURPOSE

Patients with severe ulnar neuropathy at the elbow frequently experience suboptimal surgical outcomes. Clinical symptoms alone may not accurately represent the severity of underlying nerve injury, calling for objective assessment tools, such as electrodiagnostic studies. The goal of our study was to determine whether specific electrodiagnostic parameters can be used to predict the outcomes after in situ decompression of the ulnar nerve.

METHODS

This prospective study enrolled consecutive patients aged ≥18 years diagnosed with ulnar neuropathy at the elbow. Patients completed a baseline battery of motor, sensory, functional, and electrodiagnostic tests before undergoing in situ decompression of the ulnar nerve. They were reassessed at 6 weeks, 3 months, 6 months, and 12 months after surgery. Forty-two patients completed at least 2 follow-up assessments and were included in the study.

RESULTS

When controlling for other electrodiagnostic measurements and demographic factors, none of the electrodiagnostic parameters were predictive of outcomes at 12 months after surgery. Patients with decreased compound muscle action potential amplitudes demonstrated slower trends of recovery in grip strength, pinch strength, and overall scores on the Michigan Hand Outcomes Questionnaire as well as its function, work, and activities of daily living subscales, Disabilities of the Arm, Shoulder, and Hand questionnaire, and the Carpal Tunnel Questionnaire. Decreased motor nerve conduction velocity was predictive of slower recovery of 2-point discrimination and pinch strength.

CONCLUSIONS

Compound muscle action potential amplitude, but not other conventional electrodiagnostic parameters, was predictive of functional outcomes after in situ decompression of the ulnar nerve. This parameter should play a role in determining the timing and prognosis of treatment for ulnar neuropathy at the elbow.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic II.

Outcome of Simple Decompression of Primary Cubital Tunnel Syndrome Based on Patient-Reported Outcome Measurements

PURPOSE

To evaluate the patient-reported outcome measures of patients with primary cubital tunnel syndrome and to assess whether they are affected by preoperative symptom severity.

METHODS

Patients who underwent simple decompression for primary cubital tunnel syndrome were selected from a prospectively maintained database. Outcome measurements consisted of the Boston Carpal Tunnel Questionnaire at intake and at 3 and 6 months after surgery. Also, 6 months after surgery, the patients received a question about their satisfaction with the treatment result. To determine a possible influence of preoperative symptom severity on postoperative outcomes, the sample was divided into quartiles based on symptom severity at intake.

RESULTS

One hundred and forty-five patients were included in the final analysis. On average, all patients improved on the Boston Carpal Tunnel Questionnaire. The subgroup of patients with the mildest symptoms at intake did not improve significantly on symptom severity but did improve significantly on their functional status. In addition, the patients with the most severe symptoms at intake did improve on both aspects. Moreover, no difference in satisfaction with treatment result between the severity of symptoms at intake was found.

CONCLUSIONS

The patients with the mildest symptoms at intake may not improve on symptom severity, but they do improve on functional status after simple decompression for cubital tunnel syndrome. In addition, patients with the most severe symptoms at intake do improve on both symptom severity and functional status. Moreover, all patients reported to be equally satisfied with the treatment result, which suggests that satisfaction is not dependent on the symptom severity at intake. Even those patients with both the mildest symptoms before surgery and the least improvement still seem to benefit from simple decompression.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Reporting Outcomes and Outcome Measures in Cubital Tunnel Syndrome: A Systematic Review

PURPOSE

Comparison between studies assessing outcomes after surgical treatment of cubital tunnel syndrome (CuTS) has proven to be difficult owing to variations in outcome reporting. This study aimed to identify outcomes and outcome measures used to evaluate postoperative results for CuTS.

METHODS

We performed computerized database searches of MEDLINE and EMBASE. Studies with 20 or more patients aged 18 and older who were undergoing medial epicondylectomy, endoscopic decompression, open simple decompression, or decompression with subcutaneous, submuscular, or intramuscular transposition for ulnar neuropathy at the elbow were included. Outcomes and outcome measures were extracted and tabulated.

RESULTS

Of the 101 studies included, 45 unique outcomes and 31 postoperative outcome measures were identified. These included 7 condition-specific, clinician-reported instruments; 4 condition-specific, clinician-reported instruments; 8 patient-reported, generic instruments; 11 clinician-generated instruments; and one utility measure. Outcome measures were divided into 6 unique domains. Overall, 60% of studies used condition-specific outcome measures. The frequency of any condition-specific outcome measure ranged from 1% to 37% of included studies.

CONCLUSIONS

There is marked heterogeneity in outcomes and outcome measures used to assess CuTS. A standardized core outcome set is needed to compare results of various techniques of cubital tunnel decompression.

CLINICAL RELEVANCE

This study builds on the existing literature to support the notion that there is marked heterogeneity in outcomes and outcome measures used to assess CuTS. The authors believe that a future standardized set of core outcomes is needed to limit heterogeneity among studies assessing postoperative outcomes in CuTS to compare these interventions more easily and pool results in the form of systematic reviews and meta-analyses.

The needle electromyography findings in the neurophysiological classification of ulnar neuropathy at the elbow

Background/aim

Although ulnar neuropathy at the elbow (UNE) is the second most common entrapment mononeuropathy, there are few reports on its neurophysiological classification. In this study, we tried to find out the role of needle electromyography (EMG) in the neurophysiological classification of UNE.

Materials and methods

UNE patients who met the clinical and neurophysiological diagnostic criteria and healthy individuals were included in this study. Reference values of nerve conduction studies were obtained from healthy individuals. Needle EMG was performed to all UNE patients. According to the neurophysiological classification proposed by Padua, UNE patients were classified as mild, moderate, and severe.

Results

Thirty-one controls and thirty-five UNE patients were included in the study. There was mild UNE in 23 patients, moderate UNE in 8, and severe UNE in 4. Abnormal needle EMG findings were present in all patients with moderate and severe UNE and in 12 patients with mild UNE.

Conclusion

Abnormal needle EMG findings are seen in most of the UNE patients. Therefore, it is not practical to use needle EMG findings in the neurophysiological classification. Needle EMG abnormalities may also be present in patients with mild UNE due to axonal degeneration or motor conduction block.

A Novel Diagnostic and Prognostic Tool for Simple Decompression of Ulnar Nerve in Cubital Tunnel Syndrome

BACKGROUND

Surgical decompression of the ulnar nerve (UN) is effective for treating cubital tunnel syndrome (CubTS). Nevertheless, the outcome is not always satisfying. Different surgical, clinical, and imaging findings have been claimed as outcome predictors, but there is no consensus in the literature. We analyzed the outcome-predicting role of ultrasonography (US) of the UN in patients with CubTS and its possible role for diagnosis and follow-up.

METHODS

Patients with CubTS treated by simple UN decompression underwent US and electrodiagnotic (ED) studies of the UN at the elbow before and after surgery. Outcome was evaluated through the Bishop scale. A correlation analysis between pre- and postoperative clinical, US, and ED findings was performed.

RESULTS

Thirty-six patients were enrolled. Preoperatively, we observed a negative correlation between the motor conduction velocity (MCV) and the transverse (TD) and anteroposterior diameters and cross-sectional area (CSA) of the UN at the precubital (P = 0.001, P = 0.001, P = 0.005) and cubital level (P = 0.02, P = 0.002, P = 0.001). Preoperative precubital TD and CSA were associated with outcome (P = 0.01, P = 0.006) and postoperative MCV (P = 0.004, P = 0.008). The cut-off values TD >6 mm and CSA >23.91 mm² were predictors of poor outcome. Finally, postoperative cubital TD and CSA values were inversely correlated with outcome (P = 0.0002, P = 0.0007) and postoperative MCV (P = 0.0002, P = 0.0004).

CONCLUSIONS

The US examination of the UN is useful for the management of patients with CubTS as an adjunct to clinical and ED evaluations. US measurements are correlated with pre- and postoperative ED findings and thus are useful for diagnosis and follow-up. Interestingly, specific precubital US measurements are good predictors of outcome.

Surgical Treatment of Cubital Tunnel in Pediatric Athletes

Background Cubital tunnel syndrome is the second most common upper extremity peripheral nerve entrapment syndrome. In particular, cubital tunnel has been documented occasionally in young, throwing athletes. Materials and Methods Billing databases were searched for patients undergoing surgical decompression of the ulnar nerve at the elbow, who were age 18 or younger at the time of surgery. Charts were reviewed and patients were included if they had an isolated mononeuropathy consistent with cubital tunnel syndrome and were symptomatic. Data on age of onset, duration of symptoms, Dellon classification, nerve subluxation, provocative testing results, nerve conductions, and exacerbating activities were abstracted. Patients were contacted for a postsurgical follow-up questionnaire. Results Seven patients were identified. The average age was 16, and duration of symptoms was 7 months. All seven patients had normal electrodiagnostic studies and had failed a course of conservative treatment. All were satisfied with surgery and felt improvement. One stopped playing their sport, and three had mild symptoms with varied activities. Conclusion Although uncommon, pediatric cubital tunnel syndrome does occur. Surgical release improves symptoms and return to activities. Nevertheless, some degree of symptoms often persists. Electrodiagnostic studies may be negative in many patients with an otherwise consistent history and examination. Level of Evidence This is a level IV therapeutic study.

Effect of disease duration on functional outcomes and complications after arthrolysis in patients with elbow stiffness

HYPOTHESIS

The purpose of this study was to determine the effect of a long duration of elbow stiffness on functional outcomes and complications after arthrolysis.

METHODS

Participants included consecutive patients with a long duration of elbow stiffness (≥5 years, n = 23) and control patients matched for age, sex, and initial injury type (n = 46). All patients underwent elbow arthrolysis combined with hinged external fixation between March 2014 and March 2016. At baseline and follow-up, we evaluated elbow motion (flexion, extension, supination, pronation, and range of motion) and patient-reported outcomes, including the Mayo Elbow Performance Score (MEPS) and visual analog scale for pain. Postoperative complications including infection, nerve dysfunction, and instability were recorded.

RESULTS

There were no significant differences in preoperative elbow pain, range of motion, or MEPS between groups. Postoperatively, pronation and the MEPS in patients with a long disease duration were inferior to those in control patients (P = .041 and P = .016, respectively). Patients with a long disease duration also had a significantly higher incidence of complications than control patients (P = .002). At final follow-up, 7 patients (30%) in the long disease duration group and 3 patients (7%) in the control group presented with nerve symptoms (P = .022).

CONCLUSIONS

A long duration of elbow stiffness may negatively influence functional outcomes and increase the risk of complications after arthrolysis.

What Is the Impact of Center Variability in a Multicenter International Prospective Observational Study on Developmental Dysplasia of the Hip?

BACKGROUND

Little information exists concerning the variability of presentation and differences in treatment methods for developmental dysplasia of the hip (DDH) in children < 18 months. The inherent advantages of prospective multicenter studies are well documented, but data from different centers may differ in terms of important variables such as patient demographics, diagnoses, and treatment or management decisions. The purpose of this study was to determine whether there is a difference in baseline data among the nine centers in five countries affiliated with the International Hip Dysplasia Institute to establish the need to consider the center as a key variable in multicenter studies.

QUESTIONS/PURPOSES

(1) How do patient demographics differ across participating centers at presentation? (2) How do patient diagnoses (severity and laterality) differ across centers? (3) How do initial treatment approaches differ across participating centers?

METHODS

A multicenter prospective hip dysplasia study database was analyzed from 2010 to April 2015. Patients younger than 6 months of age at diagnosis were included if at least one hip was completely dislocated, whereas patients between 6 and 18 months of age at diagnosis were included with any form of DDH. Participating centers (academic, urban, tertiary care hospitals) span five countries across three continents. Baseline data (patient demographics, diagnosis, swaddling history, baseline International Hip Dysplasia Institute classification, and initial treatment) were compared among all nine centers. A total of 496 patients were enrolled with site enrolment ranging from 10 to 117. The proportion of eligible patients who were enrolled and followed at the nine participating centers was 98%. Patient enrollment rates were similar across all sites, and data collection/completeness for relevant variables at initial presentation was comparable.

RESULTS

In total, 83% of all patients were female (410 of 496), and the median age at presentation was 2.2 months (range, 0-18 months). Breech presentation occurred more often in younger (< 6 months) than in older (6-18 months at diagnosis) patients (30% [96 of 318] versus 9% [15 of 161]; odds ratio [OR], 4.2; 95% confidence interval [CI], 2.3-7.5; p < 0.001). The Australia site was underrepresented in breech presentation in comparison to the other centers (8% [five of 66] versus 23% [111 of 479]; OR, 0.3, 95% CI, 0.1-0.7; p = 0.034). The largest diagnostic category was < 6 months, dislocated reducible (51% [253 of 496 patients]); however, the Australia and Boston sites had more irreducible dislocations compared with the other sites (ORs, 2.1 and 1.9; 95% CIs, 1.2-3.6 and 1.1-3.4; p = 0.02 and 0.015, respectively). Bilaterality was seen less often in older compared with younger patients (8% [seven of 93] versus 26% [85 of 328]; p < 0.001). The most common diagnostic group was Grade 3 (by International Hip Dysplasia Institute classification), which included 58% (51 of 88) of all classified dislocated hips. Splintage was the primary initial treatment of choice at 80% (395 of 496), but was far more likely in younger compared with older patients (94% [309 of 328] versus 18% [17 of 93]; p < 0.001).

CONCLUSIONS

With the lack of strong prognostic indicators for DDH identified to date, the center is an important variable to include as a potential predictor of treatment success or failure.

Surgical Treatment of Cubital Tunnel Syndrome: Trends and the Influence of Patient and Surgeon Characteristics

PURPOSE

To examine trends in and determinants of the use of different procedures for treatment of cubital tunnel syndrome.

METHODS

We performed a retrospective cross-sectional analysis of the Healthcare Cost and Utilization Project Florida State Ambulatory Surgery Database for 2005 to 2012. We selected all patients who underwent in situ decompression, transposition, or other surgical treatments for cubital tunnel syndrome. We tested trends in the use of these techniques and performed a multivariable analysis to examine associations among patient characteristics, surgeon case volume, and the use of different techniques.

RESULTS

Of the 26,164 patients who underwent surgery for cubital tunnel syndrome, 80% underwent in situ decompression, 16% underwent transposition, and 4% underwent other surgical treatment. Over the study period, there was a statistically significant increase in the use of in situ release and a decrease in the use of transposition. Women and patients treated by surgeons with a higher cubital tunnel surgery case volume underwent in situ release with a statistically higher incidence than other techniques.

CONCLUSIONS

In Florida, surgeon practice reflected the widespread adoption of in situ release as the primary treatment for cubital tunnel syndrome, and its relative incidence increased during the study period. Patient demographics and surgeon-level factors influenced procedure selection.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.

The dependence of age on ulnar nerve conductive study parameter adaptation after compressive ulnar neuropathy operations in the elbow

BACKGROUND

According to some studies, peripheral nerve injury healing is prolonged in elderly patients. Compressive ulnar neuropathy in the elbow (UNE) is the second most common compressive mononeuropathy. To our knowledge, no study has investigated the effect of age on the postoperative ulnar nerve injury repair rate. Our aim was to evaluate age-related differences in the electrophysiological parameters before and approximately 100 days after operations for cubital tunnel syndrome.

METHODS

This retrospective study included 103 patients who underwent in situ ulnar nerve decompressions in the elbow. The included patients suffered from paraesthesia and hypoesthesia in their ulnar nerve distribution, hypertrophy, and weakening of the hand muscles, which were innervated by the ulnar nerve. Concurrently, these patients met the EGM diagnostic criteria for UNE. The age dependency on the differences between the preoperative and postoperative parameter values that were measured during the conductive studies was estimated using a regression analysis.

RESULTS

A statistically significant deceleration of the monitored parameter adaptation, which included segmental conduction velocity in the elbow area and CMAP amplitude during the above-elbow stimulation of the ulnar nerve, was found.

CONCLUSIONS

Ulnar nerve injury repair in the cubital tunnel area after a UNE operation proceeds significantly slower in elderly patients.

Diagnosis and Treatment of Work-Related Ulnar Neuropathy at the Elbow

Ulnar neuropathy at the elbow (UNE) is the second most common entrapment neuropathy after carpal tunnel syndrome and occurs most commonly at the elbow due to mechanical forces that produce traction or ischemia to the nerve. The primary symptom associated with UNE is diminished sensation or dysesthesias in the fourth or fifth digits, often coupled with pain in the proximal medial aspect of the elbow. Treatment may be conservative or surgical, but optimal management remains controversial. Surgery should include exploration of the ulnar nerve throughout its course around the elbow and release of all compressive structures.