Does Concomitant Biceps Tenotomy Affect Shoulder Proprioception and Strength? A Prospective Intra-Individual Comparison After Arthroscopic Rotator Cuff Repair

Introduction

Rotator cuff tears are often accompanied by pathology of the long head of the biceps tendon (LHBT) [1]. Conditions such as tenosynovitis, tendinopathy, partial rupture, or complete rupture of the LHBT are recognized causes of shoulder pain that require treatment [2].

Two surgical procedures are commonly used for LHBT pathology: biceps tenotomy and biceps tenodesis. Biceps tenotomy is technically simple, quick, cost-effective, and effective in relieving pain. However, forearm cramping and Popeye deformity are considered disadvantages of this technique [3]. Biceps tenodesis is regarded as advantageous because it preserves the length and tension of the muscle. Its disadvantages include longer operative time, greater technical complexity, and potential need for revision [4]. There is a widely held view that biceps tenodesis results in less loss of elbow flexion strength than tenotomy because it maintains muscle length and tension; therefore, it is often preferred for younger patients and individuals engaged in heavy labor [4,5].

Although shoulder proprioception is not routinely emphasized in clinical examinations, it may positively influence clinical scores, particularly in patients who undergo rotator cuff repair [6]. Furthermore, there is ongoing debate regarding whether loss of shoulder proprioception increases the risk of shoulder instability [7]. Shoulder proprioception is primarily mediated by impulses from Pacinian and Ruffini corpuscles, as well as Golgi tendon organs, located in the muscles, tendons, and ligaments surrounding the shoulder [8]. The LHBT also contains a substantial number of these mechanoreceptors [9]. These factors lead to the question: “Can biceps tenotomy result in loss of shoulder proprioception?”

In this study, we aimed to examine the effects of biceps tenotomy – performed in combination with rotator cuff repair – on shoulder proprioception, elbow strength, and shoulder muscle strength. We hypothesized that this combined procedure would lead to reduced shoulder proprioception and decreased elbow strength.

Material and Methods

STUDY DESIGN AND SETTING:

This prospective, intra-individual comparison study was conducted at a single center between May 2018 and December 2021. Consecutive adult patients who underwent arthroscopic rotator cuff repair with concomitant LHBT tenotomy were screened. Outcomes were collected at a standardized postoperative visit, at least 12 months after surgery.

PATIENT SELECTION AND ELIGIBILITY:

With the approval of the Van Yüzüncü Yıl University Non-Interventional Clinical Research Ethics Committee (dated 15.04.2022, decision number 2022/04–07), the records of patients with rotator cuff tears who underwent arthroscopic repair at Dursun Odabaş Medical Center between May 2018 and December 2021 were accessed through the patient registry system. Surgical notes were retrospectively reviewed. Indications for tenotomy included degenerative LHBT tendinopathy, fraying or synovitis, partial-thickness tearing, and low-grade superior labrum anterior to posterior (SLAP) type I–II lesions in middle-aged patients. Inclusion criteria were primary arthroscopic rotator cuff repair with biceps tenotomy for degenerative rotator cuff tears and a minimum follow-up duration of 1 year after surgery. Exclusion criteria were neurological disorders affecting muscle strength or proprioception; additional surgical procedures or treatments involving either the operated shoulder or the contralateral side; planned but not yet administered treatments for either shoulder; and reruptured rotator cuffs.

In total, 167 patients who underwent rotator cuff repair with biceps tenotomy were identified through the hospital information system. Of these, 19 were excluded due to rerupture, 2 due to a history of distal radius fracture, and 4 due to prior carpal tunnel release surgery. One patient was excluded because they had been diagnosed with Parkinson’s disease. Additionally, 39 patients could not be contacted due to incorrect contact information. Ultimately, 102 patients with degenerative rotator cuff tears who underwent primary arthroscopic rotator cuff repair with biceps tenotomy and met the inclusion criteria were identified. These 102 patients were contacted by phone and verbally invited to the orthopedics and traumatology outpatient clinic to participate in a scientific study. Eighty-one patients presented to the clinic. Informed consent was obtained from each participant, and documentation of their consent was submitted to the ethics committee. Three patients were excluded because they had undergone rotator cuff repair on the contralateral shoulder at an external center. One patient was excluded due to recent surgery for an intra-articular distal humeral fracture. The remaining 77 patients were included in the analysis.

SURGICAL TECHNIQUE:

Procedures were performed under general anesthesia with the patient in the lateral decubitus position and upper-extremity traction. Rotator cuff tears were repaired using a single-row Modified Mason-Allen suture technique (Figure 1). The biceps tendon was tenotomized with a radiofrequency device at the site closest to its origin. All surgical procedures were performed by a single responsible surgeon.

PATIENT EVALUATION:

At the final examination, active complaints were documented. Patients were asked about postoperative arm pain and symptom duration. Functional outcomes were assessed using the American Shoulder and Elbow Surgeons (ASES) score and Constant score. Preoperative ASES, Visual Analog Scale (VAS), and Constant scores were retrieved from patient records, then compared with postoperative results.

Shoulder proprioception was evaluated using the active position repetition test, which is considered more specific to capsuloligamentous and musculotendinous receptors [10]. Proprioception was assessed with a pre-prepared angle measurement ruler. The patient’s eyes were occluded with a sleep band, and both shoulders were elevated to 90° with the assistance of an observer (Figure 2). A photograph was taken at the level of the shoulder joint. Next, the patient was asked to lower their arms to the side of the trunk and then actively elevate them to the same level previously assisted by the observer. While the patient performed this maneuver with eyes closed, photographs were taken at the level of the shoulder joint. The procedure was repeated 3 times to ensure objectivity. In each photograph, lines were drawn from the rotation center of the shoulder joint to the wrist using Microsoft Paint software. Photographs were then uploaded to an online tool to evaluate the angle between the drawn lines and the horizontal plane (https://www.ginifab.com/feeds/angle_measurement/). The comparison determined whether differences existed between the angles of patient-initiated and observer-assisted arm elevation (Figure 3). This procedure was performed for each of the 3 photographs, and the mean value of the measured angles was calculated. Angle differences of 3° or less were not considered significant. This assessment was repeated at 30° and 60° rotational positions, assuming shoulder elevation at 30°, 60°, and 120°, as well as at 90° of arm flexion; 0° was defined as maximum internal rotation. The presence of Popeye deformity was recorded through direct observation while the elbow was flexed, as well as during flexion and extension against resistance.

Bilateral upper extremity muscle strength was assessed with a Baseline manual muscle tester mechanical 60-pound hand dynamometer (serial no: 120902-3-0140, Fabrication Enterprises Inc., White Plains, NY, USA) equipped with 3 push and 2 pull attachments (Figure 4). To standardize testing, patients completed a brief warm-up and a seated rest period before measurements.

Patients were seated on a height-adjustable chair, and measurements were performed with the dynamometer stabilized on the table. Forearm flexion-extension and pronation-supination strengths were measured and recorded 3 times for both upper extremities with the elbow flexed at 90°. Shoulder abduction strength was measured at 90° abduction, and shoulder flexion strength was recorded at 90° flexion. Internal and external rotation strengths were measured 3 times each in standardized positions. Finally, with the shoulder extended, the elbow flexed and pronated, and the hand placed behind the back, patients were instructed to extend the shoulder against resistance. Shoulder extension strength was measured 3 times in this position. For each muscle group, the mean of 3 measurements was recorded (Figure 5).

STATISTICAL ANALYSIS:

Descriptive statistics for continuous variables are expressed as mean, standard deviation, minimum, and maximum values; categorical variables are presented as numbers and percentages. Data distribution normality was evaluated using the Shapiro-Wilk test. One-way analysis of variance was used to compare continuous variables across categorical groups. After variance analysis, the Duncan multiple comparison test was utilized to identify differing groups. Pearson correlation coefficients were calculated to evaluate associations between continuous variables, and chi-square tests were conducted to assess relationships between categorical variables. Depending on data distribution normality results, paired t-tests or Wilcoxon signed-rank tests were used to compare preoperative and postoperative measurements for selected parameters. Effect sizes for paired comparisons were reported as Cohen’s dz with 95% confidence intervals (CIs); multiplicity for paired comparisons was controlled with Holm adjustment. The threshold for statistical significance was set at P<0.05. All analyses were conducted using SPSS software version 21.0 for Windows (IBM Corp., Armonk, NY, USA).

Results

In total, 77 patients were included in the study. Twenty-one were men and 56 were women. The mean age was 58.1 years (range, 41–73). Thirteen patients (17%) were under 50 years of age. Surgery was performed on the left arm in 24 patients (9 were left-hand dominant) and on the right arm in 53 patients (all were right-hand dominant). The mean body mass index was 29.6±2.3 kg/m2. Patients participated in a structured rehabilitation program for an average of 22±12.3 days postoperatively. The mean follow-up period was 40.2±20.4 months (range, 31–71).

The mean preoperative Constant score was 50.4±12.5, and the mean preoperative ASES score was 51.4±10.3. Postoperatively, the mean Constant score was 85.1±16.2, and the mean ASES score was 84.5±13.1. Both scores increased by more than 50%, and these improvements were statistically significant (P<0.01). The mean preoperative VAS score was 6.1±1.9. Postoperatively, only 3 patients reported persistent pain, and the mean VAS score was 2.1±0.1; this decrease was statistically significant (P<0.01). Comorbidities were present in 38 patients (49%). Preoperatively, 26 patients (34%) were receiving treatment for diabetes mellitus, 20 (26%) for hypertension, 6 (8%) for chronic obstructive pulmonary disease, 6 (8%) for coronary artery disease, and 1 (1%) for familial Mediterranean fever (Table 1).

In all 77 patients, the biceps tendon was inflamed, and arthroscopic evaluation confirmed biceps tendinitis. Additionally, partial rupture of the biceps tendon was observed in 6 patients (8%), a type I SLAP lesion in 6 patients (8%), and a type II SLAP lesion in 1 patient (1%). Patients with isolated biceps tendinitis demonstrated significantly higher postoperative ASES scores (P<0.01) and Constant scores (P=0.02) relative to those with additional biceps pathology. Mean range of motion measurements for the operated and contralateral shoulders are shown in Table 2. No statistically significant differences were observed between sides concerning range of motion (P>0.05). Subgroup analyses showed no clinically meaningful variation according to age. For example, the supination difference between patients younger than 55 years and those 55 years and older was small (Δ=0.47; 95% CI, 0.02–0.93; P=0.042).

Muscle strength was measured with a dynamometer on both the operated and contralateral sides, and the results were statistically compared. Mean elbow flexion forces were 88.5±34.4 N on the operated side and 91.4±41.2 N on the contralateral side (P=0.163). Mean elbow supination forces were 50.8±18.2 N on the operated side and 44.4±14.5 N on the contralateral side (P=0.056). Shoulder abduction forces were 47.2±22.1 N on the operated side and 46.2±21.7 N on the contralateral side (P=0.481). Overall, side-to-side differences were small; only elbow and shoulder flexion differences showed statistical significance (Table 3). Representative findings included elbow flexion Δ=−0.56 (95% CI, −1.05 to −0.06; P=0.028) and shoulder flexion Δ=−0.87 (95% CI, −1.41 to −0.33; P=0.002); all other comparisons were non-significant (P≥0.055; 95% CIs spanning zero).

Shoulder proprioception was assessed using the active position repetition method. At the 30° elevation target, deviations were 2.5°±4.7° on the operated side and 3.8°±5.1° on the contralateral side (P=0.232). At the 90° elevation target, deviations were 0.58°±2.5° on the operated side and 0.57°±2.1° on the contralateral side (P=0.995). At the 60° rotation target, deviations were 2.06°±5.21° on the operated side and 1.48°±4.33° on the contralateral side. Generally, no statistically significant differences were evident between sides (P>0.05) (Table 4). Proprioception analysis (absolute error, °) confirmed the absence of clinically meaningful side-to-side differences (P≥0.129). At 30° rotation, the operated side demonstrated slightly lower error (Δ=−2.00°; 95% CI, −3.68° to −0.32°; P=0.020). Other comparisons were neither statistically nor clinically significant.

At the final follow-up, 17 patients (22%) reported cold intolerance, 5 patients (6%) reported an inability to lie on the operated shoulder, 4 patients (5%) reported shoulder pain, and 1 patient (1%) reported burning in the forearm. Postoperatively, 11 patients (14%) experienced forearm cramps, which resolved within the first 4 months. Only 1 patient (1%) presented with a Popeye sign.

Discussion

LIMITATIONS OF THE STUDY:

This study had 2 types of limitations: measurement technique and sample size. Because our institution did not have an isokinetic dynamometer or robotic device, proprioception was assessed via the active-passive method; muscle strength was evaluated using a manual dynamometer. These parameters can be measured more objectively with isokinetic or robotic systems. Additionally, only 77 patients with a mean postoperative follow-up duration of 40 months were included. Multicenter studies with larger cohorts may provide results more representative of the broader population.

Conclusions

In patients with clinical indications for tenotomy, concurrent LHBT tenotomy during arthroscopic rotator cuff repair was unrelated to measurable postoperative deficits in shoulder proprioception or upper-limb strength. These results support the clinical acceptability of tenotomy when indicated and may guide routine surgical decision-making.