Sarcomere length in wrist extensor muscles Changes may provide insights into the etiology of chronic lateral epicondylitis

Since the etiology of tennis elbow (lateral epicondylitis) is poorly understood, we studied the anatomical changes in the extensor carpi radialis brevis (ECRB) muscle during elbow joint rotation. Specifically, we measured ECRB sarcomere length, using an intraoperative laser diffraction procedure that measures muscle sarcomere length with an accuracy of ± 0.05 |xm. We found an unexpected biphasic response in ECRB sarcomere length as the elbow was rotated from full extension to full flexion. the initial sarcomere length of 3.49 μm, with the elbow extended, was gradually changed to 3.68 μm, 3.34 |xm, 3.81 μrn, and 3.45 um with progressive elbow flexion. Based on the very nonlinear mechanical properties of skeletal muscle, this “double lengthening” of the ECRB during progressive flexion would impose intense eccentric contractions on the muscle itself. Given that eccentric contractions cause muscle injury and subsequent inflammation, these findings may provide insights into the etiology of lateral epicondylitis.     

Arthroscopic release for lateral epicondylitis

Purpose: This study was performed to review the results of our early experience with recalcitrant lateral epicondylitis treated arthroscopically. Type of Study: This study is a case series consisting of consecutive patients with lateral epicondylitis treated arthroscopically by 1 surgeon. Methods: Patients failing a minimum of 6 months of conservative treatment underwent arthroscopic release of the extensor carpi radialis brevis (ECRB) origin using the proximal medial and proximal lateral portals. Associated intra-articular pathology was noted and addressed. The ECRB lesions were classified according to their gross morphology and resected with a shaver. The lateral epicondyle was then decorticated with a burr. Results: Sixteen patients with recalcitrant lateral epicondylitis were treated with arthroscopic release of the ECRB origin on the lateral epicondyle. Of the 16 elbows undergoing surgery, 5 (31.3%) were noted to have a type I lesion, characterized as fraying of the undersurface of the ECRB. Five (31.3%) had a type II lesion noted by linear tears within the ECRB, and 6 (37.5%) had a type III lesion, consisting of a partial or complete avulsion of the ECRB origin. Concurrent intra-articular pathology (synovitis, osteophytes) was noted in 3 of 16 elbows (18.8%) and was addressed arthroscopically. All patients were followed-up for a minimum of 1 year; however, 4 patients were lost to follow-up for this retrospective review due to military reassignment. Follow-up was obtained on 12 of 16 (75%) of patients at an average length of 24.1 months (range, 15 to 33 months). All patients reported improvement with the procedure. The average return to unrestricted work was 6.0 days (range, 0 to 28 days). Conclusions: Arthroscopic release effectively treats lateral epicondylitis while also affording visualization of the joint space to address associated intra-articular pathology. Additionally, arthroscopic release is minimally invasive and allows early rehabilitation and return to normal activities.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 6 (July-August), 2001: pp 582–587     

Muscle strain on the radial wrist extensors during motion-simulating stretching exercises for lateral epicondylitis: a cadaveric study

The purpose of this study is to measure muscle strain on the extensor carpi radialis longus (ECRL) and extensor carpi radialis brevis (ECRB) in cadavers and to identify effective stretching positions. In 12 frozen/thawed cadaveric arms, a strain gauge was attached to the ECRL and ECRB muscles, and increases in muscle strain were measured from a standard position (45 degrees elbow flexion, neutral forearm, and neutral wrist) to 12 sequential arm and wrist positions. Muscle strain on the ECRL and ECRB with the elbow at 45 degrees flexion was less than 10% regardless of forearm and wrist positions, whereas the majority of it was greater than 10% with the elbow extended. Maximal muscle strain on the ECRL and ECRB was obtained with elbow extension, forearm pronation, and wrist flexion-ulnar deviation, with mean values of 17.8% and 13.8%, respectively (greater than standard position, P < .05). Muscle stretching of the wrist extensors for lateral epicondylitis should be performed in this position.     

Functional outcomes after arthroscopic treatment of lateral epicondylitis

Background  The purpose of this study was to evaluate surgical outcomes of arthroscopic débridement for lateral epicondylitis using a validated, patient-assessed scoring system as well as conventional outcome measures. We also wanted to identify potential predictive factors that may be associated with the outcomes. Methods  A total of 20 elbows in 18 patients with chronic lateral epicondylitis who underwent arthroscopic surgery were included. There were nine men and nine women with a mean age of 54 years (range 42–71 years). Operative treatment consisted of débridement of the extensor carpi radialis brevis (ECRB) origin and resection of the radiocapitellar synovial plica interposed in the joint. Outcomes were assessed using a patient rating, visual analogue scale (VAS) pain score, the Japanese Orthopaedic Association (JOA) elbow score, and the Disability of the Arm, Shoulder, and Hand (DASH) questionnaire. The average length of follow-up was 28 months (range 24–40 months). Results  After surgery, according to the patients’ reports, 14 of 20 elbows were much better, and 6 elbows were better. A mean preoperative VAS pain score at rest of 3.9 points improved to 0.3 points (P < 0.0001), and that during activity improved from 7.8 points to 0.9 points (P < 0.0001). The mean preoperative JOA elbow score of 29 points was improved to 90 points (P < 0.0001). The mean postoperative DASH score was 10.6 (range 0–50). Absent of T2-weighted high signal focus of the ECRB origin on preoperative magnetic resonance imaging (MRI) (P = 0.02) and receiving public assistance (P = 0.01) were significantly associated with worse DASH scores. Conclusions  Arthroscopic release was a satisfactory procedure for chronic lateral epicondylitis. Preoperative MRI of the ECRB origin and socioeconomic factors were significantly associated with postoperative residual symptoms evaluated with the DASH score.     

Anconeus muscle transposition for failed surgical treatment of tennis elbow: preliminary results

The authors conducted a retrospective study on their first 10 patients treated with an anconeus muscle transposition after failed surgery for chronic lateral epicondylitis. All patients had initially been treated conservatively, and subsequently with a classical or percutaneous release of the common extensor origin. The secundary procedure involved wide excision of the common extensor origin, débridement of the lateral epicondyle and rotation of the anconeus muscle into the defect. At follow-up the results were excellent in 3 patients, good in 4 and poor in 3. This appears as a valid salvage procedure for lateral epicondylitis, since the operation was performed as a second or even a third approach.     

The role of the extensor digitorum communis muscle in lateral epicondylitis

A common finding in tennis elbow is pain in the region of the lateral epicondyle during resisted extension of the middle finger (Maudsley's test). We hypothesized that the pain is due to disease in the extensor digitorum communis muscle, rather than to compression of the radial nerve or disease within extensor carpi radialis brevis. Thirteen human forearm specimens were examined. It was found that the extensor digitorum communis was separable into four parts. The part to the middle finger originated from the lateral epicondyle, but the muscle slips to the other fingers originated more distally. Pain ratings were measured in ten patients diagnosed with lateral epicondylitis during isometric finger and wrist extension tests. The results confirmed the high prevalence of a positive Maudsley's test in lateral epicondylitis, and also that the patients with tenderness at the site of origin of the extensor digitorum communis slip to the middle finger had the greatest pain during middle finger extension. These anatomical and clinical findings clarify the anatomy of extensor digitorum communis, and suggest that this muscle forms the basis for the Maudsley's test. The muscle may play a greater role in tennis elbow than previously appreciated.     

A dynamic extensor brace reduces electromyographic activity of wrist extensor muscles in patients with lateral epicondylalgia

STUDY DESIGN: Semiexperimental study. OBJECTIVE: To investigate the effect of an external wrist extension force on extensor muscle activity during hand gripping in patients with lateral epicondylalgia. BACKGROUND: Lateral epicondylalgia or "tennis elbow" is a common, often disabling ailment affecting millions of people. An optimal treatment strategy remains to be identified. The use of an external wrist extension force may reduce the extensor muscle activity during gripping in these patients. METHODS: Muscle activity of the extensor carpi radialis brevis (ECRB), extensor digitorum communis (EDC), and extensor carpi radialis longus (ECRL) was measured using surface EMG. Subjects gripped at an intensity of 10%, 20%, and 30% of the maximum voluntary contraction (MVC) force with and without the dynamic extensor brace and with and without an applied external wrist extension force of 1%, 2%, and 3% of MVC. RESULTS: At all levels of MVC gripping, the EMG signal of the ECRB and EDC were significantly lower for gripping with than without brace. An extension force of 3% of the MVC force significantly reduced the EMG signal of all muscles in almost all measurement conditions. CONCLUSIONS: The results of this study indicate that the dynamic extensor brace as well as the external extension force significantly reduced the EMG signal of the wrist extensor muscles during gripping in patients with lateral epicondylalgia. Based on these results, the dynamic extensor brace could be a promising new intervention for lateral epicondylalgia.     

Comparison of Clinical Outcomes of Platelet-Rich Plasma for Epicondylitis,Elbow: Simultaneous Lateral and Medial Versus Lateral Versus Medial

Objective

Lateral and medial epicondylitis are relatively common diseases, but they do not improve quickly and are known to reduce patients' quality of life. Much research has been done on Platelet-Rich Plasma (PRP) as a treatment for lateral epicondylitis, but research on medial epicondylitis is lacking. The purpose of this study is to compare: (i) the pain intensity; and (ii) the functional outcome between the simultaneous treatment of medial and lateral epicondylitis and the treatment of only lateral or medial epicondylitis using PRP.

Methods

In this retrospective study, 209 patients treated with PRP on epicondylitis between March 2018 and December 2021 were enrolled. Simultaneous treatment was underwent 68 patients (group I). Seventy patients were treated for lateral epicondylitis (group II). The remaining 71 patients were treated for medial epicondylitis (group III). The visual analogue scale for pain (VAS) and the Mayo elbow performance score (MEPS) were evaluated for clinical outcomes at the initial visit and 6 months after injection.

Results

VAS for pain and MEPS showed significant improvement in all three groups compared to before treatment. There was no significant difference between three groups on –ΔVAS (P > 0.05). However, in case of ΔMEPS, group III showed significantly lower compared to groups II and III (P < 0.05). No patients showed worsening of symptoms or complications during the treatment.

Conclusion

PRP injection for the patient with elbow medial and lateral epicondylitis can be treated effectively simultaneously in terms of pain. From a functional point of view, the effect of simultaneous treatment may be lessened than in the case of only lateral and medial treatment.     

Reliability of a patient-rated forearm evaluation questionnaire for patients with lateral epicondylitis.

PURPOSE: To determine the reliability of a questionnaire designed to assess forearm pain and function in patients with lateral epicondylitis. METHODS: Forty-seven patients with unilateral lateral epicondylitis completed a patient-related forearm evaluation questionnaire (PRFEQ) on two occasions. Intraclass correlation coefficients (ICC 2,1), standard error of measurement (SEM), and 95% confidence intervals (CIs) were determined for the whole group and for three subgroup comparisons of male vs. female subjects, subacute vs. chronic lateral epicondylitis, and work-related vs. non-work-related lateral epicondylitis. RESULTS: The test-retest reliability for the overall PRFEQ (ICC, 0.89), and its pain (ICC, 0.89) and function (ICC, 0.83) subscales was excellent. Test-retest reliability for patients with work-related lateral epicondylitis (ICC, 0.80) was significantly (p = 0.018) less than for patients with non-work-related lateral epicondylitis (ICC, 0.94). CONCLUSIONS: The PRFEQ can provide a simple, quick, and reliable estimate of arm pain and function in patients with lateral epicondylitis. However, large SEM and 95% CIs limit its ability to accurately predict individual scores.     

A unified approach to radial tunnel syndrome and lateral tendinosis

Two of the most common diagnoses assigned to patients presenting with lateral elbow and proximal forearm pain are lateral tendinosis and radial tunnel syndrome. Traditionally, these 2 conditions have been treated as distinct and separate entities with most patients being diagnosed with either one or the other, but not both. The extensor carpi radialis brevis (ECRB) and, to a lesser the degree, a portion of the extensor digitorum communis that form the conjoined lateral extensor tendon are thought to be primarily responsible for the excessive traction that induces lateral tendinosis (a degenerative process of microtears in the tendon with impaired healing), but the supinator blends with these same fibers and shares a role in the pathology. The supinator, primarily the arcade of Frohse, has been thought to play the majority role in compressing the posterior interosseous nerve in radial tunnel syndrome, but the undersurface thick tendon of the ECRB may also cause substantial nerve compression. Reduction of the linear tension transmitted by the ECRB is the common element in the various surgical treatments for lateral tendinosis, performed anywhere from directly at the lateral epicondyle to the distal myotendinous junction. Nerve decompression by division of fascial bands is the goal in surgery for radial tunnel syndrome. These 2 surgical approaches need not be mutually exclusive. In fact, this separation of the 2 clinical entities may play a role in the unpredictable results reported in the literature. This article presents a unified approach to treating both pathologies simultaneously including short-term clinical results.     

肘关节镜序贯性建立前方三入路技术治疗顽固性网球肘

目的评价关节镜下序贯性建立肘关节前方三入路的方法治疗顽固性网球肘的可行性、安全性和有效性。 方法回顾性分析2008年1月至2016年12月中山大学孙逸仙纪念医院收治的28例关节镜治疗顽固性网球肘的病例，均采用序贯性建立肘关节前方三入路的方法，镜下彻底清除桡侧腕短伸肌腱（extensor carpi radialis brevis，ECRB）病变的腱性组织，同时清理ECRB止点处肱骨外上髁。通过对比术前、术后的视觉模拟评分（visual analogue scale，VAS）、肌力评分以及简版上肢功能评估（quick-disabilities of arm，shoulder and hand，Quick-DASH）评分，结合末次随访的满意度，评价临床疗效。 结果28例患者均获得12~38个月的随访，临床结果显示患者VAS（夜间痛及活动痛）、肌力评分、Quick-DASH评分术前与末次随访比较，差异具有统计学意义（P<0.01）。结合满意度评分末次随访得分为优的患者18例，得分为良的患者6例，优良率为85.7%。所有患者无肘关节神经损伤等并发症。 结论通过序贯性建立肘关节前方三入路的方法，关节镜下可以彻底清除ECRB的病变组织，同时可以清理局部肱骨外上髁，是治疗顽固性网球肘的一种微创、安全、有效可行的方法。     

改良Nirschl术清理带线锚钉重建桡侧腕短伸肌腱起点治疗顽固性网球肘的临床疗效

目的进行改良Nirschl术清理带线锚钉重建桡侧腕短伸肌腱（extensor carpi radialis brevis tendon,ECRB）起点与单纯改良Nirschl术清理ECRB起点治疗顽固性网球肘的临床疗效比较，探讨带线锚钉重建ECRB起点治疗顽固性网球肘的疗效性及必要性。 方法2013年3月至2016年5月，台州骨伤医院收治的顽固性网球肘患者45例，随机分为观察组和对照组，观察组23例，对照组22例。观察组患者于改良Nirschl术式下切开清理ECRB起点退行性变性肌腱后使用带线锚钉将ECRB重新固定于去除皮质的肱骨外上髁上重建起点，对照组患者于改良Nirschl术式下单纯切开清理ECRB起点退行性变性肌腱。观察比较两组术前及术后2、3、6、12个月的疼痛、握力、重返工作时间、Mayo肘关节功能评分、Verhaar评分。 结果45例患者均完成试验观察，术后切口均为Ⅰ期愈合。观察组术后（4.97±1.33）个月恢复原工作，与对照组术后（3.55±1.27）个月比较，差异有统计学意义（P<0.05）。术后2、3个月Mayo肘关节功能评分观察组均低于对照组，差异有统计学意义（P<0.05），术后12个月Mayo肘关节功能评分观察组优于对照组，差异有统计学意义（P<0.05）；术后12个月两组视觉模拟评分（visual analogue score，VAS）差异有统计学意义（P<0.01）；术后2、3个月握力观察组均低于对照组，差异有统计学意义（P<0.05），术后6、12个月握力观察组均优于对照组，差异有统计学意义（P<0.05）；末次随访Verhaar评分观察组优于对照组，差异有统计学意义（P<0.05 ）。 结论进行改良Nirschl术清理带线锚钉重建ECRB起点治疗顽固性网球肘，手术操作简便，创伤小，将ECRB重新缝合于肱骨外上髁重建起点，恢复其临床解剖位置，使前臂伸肌力量得到最大限度恢复，能使患者恢复至正常的运动和生活水平。     

Painful neuroma of the posterior cutaneous nerve of the forearm after surgery for lateral humeral epicondylitis

PURPOSE: To describe a neuroma of the posterior cutaneous nerve of the forearm that can be the source of pain after surgery for lateral humeral epicondylitis. METHODS: A retrospective chart review of 9 patients having pain after surgery for lateral humeral epicondylitis was conducted to evaluate their history of pain, surgical findings during exploration of their painful lateral elbow scar, and outcome of their surgical treatment. RESULTS: In each of the 9 patients a neuroma of the posterior cutaneous nerve of the forearm was found to be within the scar of the original lateral epicondylitis surgery. For each of these patients the surgical treatment included resection of the neuroma and implantation of the proximal end of the nerve into the brachioradialis muscle proximal to the elbow joint. With this approach 8 of the patients had excellent pain relief and 1 had good pain relief at a mean follow-up time of 1.4 years (range, 1.0-2.6 years). CONCLUSIONS: Pain in the region of the scar after surgery to treat lateral humeral epicondylitis can be caused by a neuroma of the posterior cutaneous nerve of the forearm and this painful neuroma can be treated successfully by neuroma resection and implantation of the nerve proximally into the brachioradialis muscle.     

Pronator teres is an appropriate donor muscle for restoration of wrist and thumb extension

OBJECTIVE: To compare the detailed architectural properties of the pronator teres (PT), extensor carpi radialis brevis (ECRB), and extensor pollicis longus (EPL) muscles to evaluate the suitability of PT-to-ECRB and PT-to-EPL surgical procedures. METHODS: Muscle physiologic cross-sectional areas and region-specific muscle fiber lengths were measured in cadaveric PT, ECRB, and EPL muscles (n = 10 muscles of each type). One-way repeated-analyses of variance measures and post hoc t tests with Bonferroni corrections were used for statistical comparisons. RESULTS: The ulnar head of the PT was present in 8 of 10 specimens. The average PT fiber length was similar to that of the ECRB (7.02 +/- 0.49 cm vs 6.17 +/- 0.27 cm) but was significantly longer than that of the EPL (5.44 +/- 0.25 mm). Fiber length in the humeral head of the PT was longer compared with the ulnar head (7.19 +/- 0.52 cm vs 4.14 +/- 0.25 cm). The average physiologic cross-sectional area of the PT was similar to that of the ECRB (3.5 +/- 0.4 cm2 vs 3.3 +/- 0.3 cm2) but was significantly larger than that of the EPL (3.5 +/- 0.4 cm2 vs 1.1 +/- 0.1 cm2). CONCLUSIONS: From an architectural point of view the PT is an excellent donor choice for transfer to the ECRB for restoration of wrist extension or to the EPL for restoration of thumb extension. Because there is fiber length heterogeneity within the PT, however, when the ulnar head is present it may limit the total excursion of the donor muscle. These data suggest that releasing the ulnar head of the PT before transfer may result in larger excursions of this important motor in tendon transfer surgery.     

Outcome of release of the lateral extensor muscle origin for epicondylitis.

Fifty-five elbows in 53 patients affected by lateral epicondylitis for more than a year were operated on with lateral extensor release. Fifty-one patients (53 elbows) were followed-up 90 months postoperatively by two independent observers using Verhaar's score and the subjective grading scheme described by Svernl?v and Adolfsson. According to Verhaar's score 26 (49%) were excellent or good and 27 (51%) fair or poor. Women had significantly worse results than men (p<0.005). In the self-assessment there was no significant difference between men and women and 20 (40%) of the patients rated their elbows as completely recovered, 26 (47%) as improved, 7 (13%) as unchanged, and none as worse. Patients whose symptoms remained unchanged after operation were re-examined and found to have other conditions that were likely to have caused the pain. Lateral release can reduce symptoms in chronic lateral epicondylitis but some residual pain can be anticipated.     

In vivo investigation of ECRB tendons with microdialysis technique--no signs of inflammation but high amounts of glutamate in tennis elbow

We used the microdialysis technique to study concentrations of substances in the extensor carpi radialis brevis (ECRB) tendon in patients with tennis elbow. In 4 patients (mean age 41 years, 3 men) with a long duration of localized pain at the ECRB muscle origin, and in 4 controls (mean age 36 years, 2 men) with no history of elbow pain, a standard microdialysis catheter was inserted into the ECRB tendon under local anesthesia. The local concentrations of the neurotransmitter glutamate and prostaglandin E2 (PGE2) were recorded under resting conditions. Samplings were done every 15 minutes during a 2-hour period. We found higher mean concentrations of glutamate in ECRB tendons from patients with tennis elbow than in tendons from controls (215 vs. 69 micromoL/L, p < 0.001). There were no significant differences in the mean concentrations of PGE2 (74 vs. 86 pg/mL). In conclusion, in situ microdialysis can be used to study certain metabolic events in the ECRB tendon of the elbow. Our findings indicate involvement of the excitatory neurotransmitter glutamate, but no biochemical signs of inflammation (normal PGE2 levels) in ECRB tendons from patients with tennis elbow.     

Magnetic resonance imaging in lateral epicondylitis of the elbow

The purpose of the study was to determine the changes that might be detected using magnetic resonance imaging (MRI) on patients with chronic lateral epicondylitis of the elbow and to judge its value concerning the clinical treatment. Thirty-four patients with chronic lateral epicondylitis were included in a prospective study. All individuals underwent MRI of the elbow on a 0.2-T dedicated system. The MRI findings were interpreted by an independent radiologist without knowledge of the clinical findings. In 6 surgical cases an additional histological study was done. The biopsy of the extensor tendon was performed for correlation with the MRI. In 21 of 34 symptomatic patients, increased signal changes in T₁- and T₂-weighted images were seen. In a further 11 cases, the morphology and signal intensity were normal. The histopathological analysis of 6 surgical cases confirmed the preoperative MRI findings by showing either focal fibrous degenerative tendon tissue or microruptures of collagenous fibres. MRI in patients with chronic lateral epicondylitis can help to differentiate the disease and may be of use in clinical management, preoperative planning, and in the evaluation of the degree of degeneration at the common extensor tendon insertion. Received: 4 March 1998     

Outcome of release of the lateral extensor muscle origin for epicondylitis

Fifty-five elbows in 53 patients affected by lateral epicondylitis for more than a year were operated on with lateral extensor release. Fifty-one patients (53 elbows) were followed-up 90?months postoperatively by two independent observers using Verhaar's score and the subjective grading scheme described by Svernlöv and Adolfsson. According to Verhaar‘s score 26 (49%) were excellent or good and 27 (51%) fair or poor. Women had significantly worse results than men (p<0.005). In the self-assessment there was no significant difference between men and women and 20 (40%) of the patients rated their elbows as completely recovered, 26 (47%) as improved, 7 (13%) as unchanged, and none as worse. Patients whose symptoms remained unchanged after operation were re-examined and found to have other conditions that were likely to have caused the pain. Lateral release can reduce symptoms in chronic lateral epicondylitis but some residual pain can be anticipated.