Lift-off Test Research Articles

Subscapularis-sparing Deltopectoral Approach to the Shoulder

The deltopectoral approach is a popular exposure for shoulder surgery. It requires release of the subscapularis and anterior capsule to gain access to the glenohumeral joint. Subscapularis dysfunction, rupture, and shoulder instability have been reported after the traditional deltopectoral approach. We describe a novel surgical approach to prevent this complication by detaching only the inferior 30% to 50% of the subscapularis during humeral head resurfacing and present the preliminary results. Twenty shoulders in 20 patients were treated with humeral head resurfacing using the subscapularis-sparing technique. The surgical approach used an L-shaped flap of the lower subscapularis. The superior 50% to 70% of the insertion was left intact. The humeral head was delivered through the capsulotomy inferior to the remaining intact subscapularis tendon. After the resurfacing, the subscapularis capsule flap was repaired anatomically using a suture anchor technique. Patients were evaluated at mean follow-up of 18 months. Average active shoulder flexion improved by 56 degrees, abduction improved by 56 degrees, and external rotation improved by 54 degrees. The mean shoulder scores improved as follows: University of California at Los Angeles 19 to 25, American Shoulder and Elbow Surgeons 34 to 65, Bankart 57 to 82, and Constant 37 to 69 (P<0.05). The elbow forward belly push and lift-off tests were negative at 4 weeks postoperatively and at the last follow-up visit. Eighteen of the 20 shoulders had good-to-excellent results. With the morbidity caused by failure or dysfunction of the subscapularis after the deltopectoral approach, we believe that the subscapularis-sparing technique minimizes the trauma and risk of failure to the repair and may provide several potential advantages.

Sports Medicine Imaging Update

A healthy 18-year-old right-hand-dominant high school football player presented 6 weeks following an injury to his right shoulder. While playing right defensive end, the patient made an inside move on the opposing lineman, and another player collided with the medial aspect of his arm. The collision caused abrupt deceleration of both players and forced the injured player’s humerus to externally rotate. The arm did not dislocate, and the patient did not describe any instability, but he did experience acute right anterior shoulder pain and transient numbness. He finished the game and continued to play football in the intervening weeks. Initially he experienced night pain, but his main symptom was loss of strength (weakness of internal rotation) and dysesthesias in his right deltoid. He kept his arm more adducted during subsequent games to avoid pain and found it necessary to elevate his arm in order to extend the humerus to tackle. Despite aggressive training, he was unable to regain strength. Physical examination at presentation revealed a neurovascularly intact right upper extremity and good motion of the neck without pain. He showed no muscle atrophy but struggled to lift his right arm. He had a positive lift-off test and a positive O’Brien sign on the affected shoulder. Strength testing of the rotator cuff showed internal rotation weakness. His triceps muscle was strong, and his reflexes were rated as 2+ biceps and brachioradialis bilaterally, 1+ triceps on the left, and absent on the right. Electrodiagnostic testing showed no evidence of a brachial plexopathy. Radiographs showed a small ossific density anterior and medial to the humeral head that was seen on the West Point (Figure 1) and Stryker Notch views, possibly indicating a lesser tuberosity avulsion fracture, but only noted following magnetic resonance imaging (MRI). Magnetic resonance imaging demonstrated an avulsion of the subscapularis tendon with a fragment of bone that was displaced posteromedially (Figures 1-​-3).3). The tear comprised more than 50% of the subscapularis footprint without dislocation of the long head of the biceps tendon from the intertubercular groove. The superior-most fibers of the subscapularis were intact. There was injury to the anterior capsule without humeral or scapular avulsion of the anterior band of the inferior glenohumeral ligament. There was no Bankart lesion. Figure 1. West Point radiographic projection of the right shoulder demonstrate a small ossific density (arrow) anterior to the humeral head. Figure 3. Oblique sagittal intermediate echo-time fast-spin-echo MRI of the right shoulder demonstrates the avulsion fragment (arrow) surrounded by high-signal intensity fluid. Note the superior and anterior subscapularis tendon fibers, which were not disrupted, ... Figure 2. Axial intermediate echo-time fast-spin-echo MRI of the right shoulder demonstrates the avulsion fragment (arrow) displaced medially into the defect created by the subscapularis tendon tear. The superficial fibers of the subscapularis tendon are hyperintense ... At arthroscopy, a small split in the tissue overlying the subscapularis was identified; within this split, the tendon of the subscapularis was medially retracted. A small bone fragment was found at the edge of the retracted tendon. Debridement of the footprint of the subscapularis tendon was performed, and an anchor was placed. Debridement of the small bone fragment was also carried out, and the subscapularis was reattached directly using 2 sutures.

Subscapularis function after primary tendon to tendon repair in patients after replacement arthroplasty of the shoulder

We studied the results of tendon-to-tendon repair of the subscapularis during total shoulder arthroplasty (TSA) to compare its clinical results relative to more recent studies looking at osteotomy of the lesser tuberosity. This study analyzed the postoperative integrity of the subscapularis by a tendon-to-tendon repair in 45 arthroplasties in 43 patients. Preoperatively, 23 patients had a negative lift-off test; 22 could not perform the test. Postoperatively, 41 patients had a negative lift-off test; four could not reach behind themselves to do the test. All 45 shoulders had a negative belly-press test pre-operatively and post-operatively. Tendon-to-tendon repair is simpler, quicker, and avoids the possibility of an osteotomy nonunion. Tendon-to-tendon repair of the subscapularis tenotomy in shoulder arthroplasty remains an option in the presence of reasonable quality tendon, utilizing relaxing sutures (partial closure of the lateral rotator interval), and limiting early postoperative passive external rotation. Level 4; Retrospective case series, no control group.

Compliant Hybrid Journal Bearings Using Integral Wire Mesh Dampers

The following work presents a new type of hybrid journal bearing developed for enabling oil-free operation of high performance turbomachinery. The new design integrates compliant hydrostatic-hydrodynamic partitioned bearing pads with two flexibly mounted integral wire mesh dampers. The primary aim of the new bearing configuration was to maximize the load-carrying capacity and effective damping levels while maintaining adequate compliance to misalignment and variations in rotor geometry. The concept of operation is discussed along with the description of the bearing design. Several experiments using room temperature air as the working fluid were performed that demonstrate proof of concept, which include lift-off tests, bearing load tests, and rotordynamic characterization tests. The experiments demonstrate stable operation to 40,000 rpm (2.8×106 DN) of a 2.750 in. (70 mm) diameter bearing. In addition to the experimental results, an analytical model is presented for the compliant bearing system. The aeroelastic theory couples the steady state numerical solution of the compressible Reynolds flow equation with a flexible structure possessing translational and rotational compliance. This was achieved by formulating a fluid-structure force balance for each partitioned bearing pad while maintaining a global mass flow balance through the hydrostatic restrictors and bearing lands. Example numerical results for pad pressure profile, film thickness, torque, and leakage are shown.

Subscapularis repair after shoulder arthroplasty: Biomechanical and clinical validation of a novel technique

We hypothesized that releasing the subscapularis with lesser tuberosity bone may improve strength of fixation of the subscapularis during total shoulder atthroplasty (TSA). In 15 cadaveric humeri, all musculature was removed except the subscapularis. A standard humeral head osteotomy was performed for TSA. The subscapularis was released with a fleck of lesser tuberosity bone in 10 specimens from five matched pairs, and a tenotomy was performed in five. Five osteotomies were repaired with single-row heavy non-absorbable sutures and five with an additional double-row. Repairs were subjected to cyclical loading at 180 newtons for 400 cycles, increasing by 180 newtons to failure. A retrospective review of 100 consecutive patients who underwent dual-row repair of the subscapularis fleck osteotomy following TSA was also performed with minimal follow-up of 24 months (24-48). Both single (430 N) and double-row (466 N) fixation of the fleck osteotomy were significantly stronger than tenotomy suture repair (252 N) (p < .04). There was no significant difference between single and double-row ultimate strengths. Qualitatively, double-row fixation fixed the fleck osteotomy more securely to the donor site with respect to gross rotational motion. At final clinical review, the lift-off test was rated as normal in 79%. The belly press was rated as normal in 86%. Eighty-two percent were able to tuck in their shirts. Subscapularis release with fleck osteotomy provides superior biomechanical ultimate strength compared to standard tenotomy. There was no visible motion during biomechanical testing with dual-row osteotomy fixation compared to single-row fixation. Clinical results of this dual-row technique document showed good restoration of subscapularis integrity for activities of daily living. Basic science study and level 4; retrospective review, case series, no control group.

The assessment of the fracture behavior in spin-on organosilicates by nanoindentation and nanoscratch tests

Fracture behavior of the copolymers proposed as interlayer dielectric candidates is examined to find the adequate amount of bis(trimethoxysilyl)ethane to methyltrimethoxysilane that can optimize mechanical properties. In spite of the shortcoming that provides a result for comparison purpose, the indentation test becomes a good alternative to estimate cohesive and adhesive fracture strength simultaneously. The scratch test can also be used to evaluate adhesive fracture strength. The similarity between the scratch test and the chemical mechanical planarization process may offer a clue for predicting the possibility of failure during fabrication procedure. The sequence of magnitude in critical loads measured from both tests corresponds with that of fracture toughness assessed by the modified edge lift-off test.

An assessment of the inter examiner reliability of clinical tests for subacromial impingement and rotator cuff integrity

Over 30 separate clinical signs for the shoulder have been described, most with little evidence to support their accuracy and reliability. The aim of our study was to evaluate the accuracy and reliability of some of the commonly used tests for rotator cuff disease. Two clinicians, a consultant with an established shoulder practice and a registrar with an interest in shoulder surgery, examined 63 patients with history suggestive of rotator cuff disease. A set of pre-determined clinical tests for impingement syndrome and rotator cuff tear were standardised and agreed upon before the study was commenced. The examination included eliciting a painful arc, the drop arm test, the Neer’s and the Hawkin’s sign for impingement syndrome. Integrity of the individual components of the rotator cuff was assessed by the strength of abduction initiation and at 90° abduction for supraspinatus tear (Jobe’s test), Speed’s and Yergason’s test for biceps pathology, strength of shoulder external rotation for infraspinatus tears and the Gerber lift-off test for subscapularis tears. Accuracy assessments were determined by comparing clinical findings against findings at arthroscopy in 50 of the 63 patients. The two observers did not differ significantly in their assessments. Un-weighted kappa values defining agreement between the two observers and the positive predictive values were evaluated. Our findings indicate that clinical signs can be relied upon for diagnosis of impingement but not for rotator cuff deficiency. Compared with other previously published studies, our study demonstrates that the inter observer agreement is better when the assessors have a special interest and understanding of shoulder disorders.

外傷性肩関節前方不安定症におけるGerber's lift-off testの有用性

外傷性肩関節前方不安定症におけるGerber's lift-off testの有用性

Most clinical tests cannot accurately diagnose rotator cuff pathology: a systematic review

Do clinical tests accurately diagnose rotator cuff pathology? A systematic review of investigations into the diagnostic accuracy of clinical tests for rotator cuff pathology. People with shoulder pain who underwent clinical testing in order to diagnose rotator cuff pathology. The diagnostic accuracy of clinical tests was determined using likelihood ratios. Thirteen studies met the inclusion criteria. The 13 studies evaluated 14 clinical tests in 89 separate evaluations of diagnostic accuracy. Only one evaluation, palpation for supraspinatus ruptures, resulted in significant positive and negative likelihood ratios. Eight of the 89 evaluations resulted in either significant positive or negative likelihood ratios. However, none of these eight positive or negative likelihood ratios were found in other studies. Of the 89 evaluations of clinical tests 71 (80%) did not result in either significant positive or negative likelihood ratio evaluations across different studies. Overall, most tests for rotator cuff pathology were inaccurate and cannot be recommended for clinical use. At best, suspicion of a rotator cuff tear may be heightened by a positive palpation, combined Hawkins/painful arc/infraspinatus test, Napoleon test, lift-off test, belly-press test, or drop-arm test, and it may be reduced by a negative palpation, empty can test or Hawkins-Kennedy test.

Interfacial strengths of organosilicate glasses deposited on silicon wafers

The interfacial strengths of organosilicate glasses deposited on silicon wafer have been investigated. Three different testing methods, the microscratch test, four-point bending test, and the modified edge lift-off test, were used to determine the interfacial strengths between the inorganic C-doped organosilicate glass (OSG) and the silicon wafer. The results show that the adhesion energy decreases with increasing film thickness in the four-point bending and modified edge lift-off tests, but it increases as the thickness increases in the microscratch test. The difference in the trends is due to the different deformation modes operating in the testing processes.

The effect of mastectomy and radiotherapy for breast carcinoma soft tissues of the shooulder and its joint mobility among Egyptian patients

Patients with post mastectomy soft tissue shoulder disorders usually benefit from various lines of physiotherapy treatment. However, the controversy about their efficacy persists. The aim of this work was to study and assess the efficacy of each, and to identify the best intervention. One hundred female patients with ipsilateral post mastectomy shoulder problems were enrolled in the study, from September 2003 until December 2004. They were followed up for 32 weeks. Mastectomy, both radical and conservative and axillary lymph node clearance, was the standard surgery applied for operable breast carcinoma in this series. Clinical examination was followed by testing for the shoulder complaint by measuring maximal protrusion at the inferior scapular angle, scapular stabilization and the lift-off tests. Approved physiotherapy modalities were then applied, viz: no treatment (randomly chosen 12 patients), passive and active motion therapy (14 patients), oral diclofenac sodium (19 patients), local triamcinilone injection (40 patients) and manually applied low intensity laser therapy (15 patients). Assessment was by determining overall success rate for each intervention modality. Intervention outcome was assessed at 8, 16, and 32 weeks as shown by physical examination using the healthy shoulder as a reference, and by measuring restricted mobility during passive lateral rotation and glenohumeral abduction. "Success rate" was determined separately for each group at the end of the intervention period. The applied surgery was followed by radiotherapy in 96%, chemotherapy in 24% and both in 11%. The presenting post mastectomy symptoms at the shoulder were pain (100%), shoulder weakness (88%), winging of the scapula (11%) and inability to perform everyday shoulder movements (23%). Evaluation was by overall improvement score. The results were: 14.3% for untreated patients, 43.3% for those treated by motion therapy, 42% for diclofenac therapy, 80.7% for local triamcinolone, and lastly 68% for low intensity laser therapy. All treatment regimens for shoulder disabilities in those patients gave little long-term advantage, local steroid injections were the most effective. Low level laser therapy may augment its effect. It is concluded that all treatment regimens provide little long-term advantage; however, trimcinilone local injections may be the most useful in terms of pain relief and improvement in shoulder movement.

Timing of return of subscapularis function in open capsular shift patients

Loss of subscapularis function can be a significant complication after any surgery that involves its tenotomy. Recently, this complication has received more recognition after anterior approaches for shoulder replacement. It is unclear, however, whether this occurs in younger patients, and if so, how long it persists postoperatively. This study investigated the time it takes for subscapularis function to return after open tenotomy in young patients with instability. Sixteen consecutive patients underwent an anterior stabilization procedure for glenohumeral instability in which the subscapularis was taken down to perform an anterior capsular shift. Each patient was followed up prospectively for return of subscapularis function as determined by the belly-press and lift-off tests. The average time for subscapularis function to return was 8.4 weeks for the lift-off test and 8.8 weeks for the belly-press test. All patients had a negative belly-press test by 12 weeks and a negative lift-off test by 20 weeks.

Adhesion properties of polymethylsilsesquioxane based low dielectric constant materials by the modified edge lift-off test

Delamination occurring during the chemical and mechanical planarization process or wire bonding steps in packaging is a fundamental issue in integrating of low dielectric constant (low-k) materials into the multilayer structures of semiconductor chips. Since it is known that low adhesion strength is mainly attributed to the failure phenomenon, the measurement of interfacial fracture toughness is critical to provide a quantitative basis in the choice of the materials. In this study, a modified edge lift-off test was adopted to measure the fracture toughness of polymethylsilsesquioxane based low-k materials with various chemical and physical structures. Interfacial fracture toughness was improved by adding multi-functional monomers to methylsilsesquioxane monomers or by increasing the percentage of functional end groups inside the prepolymers. In addition, the change in curing conditions and thickness influenced the adhesion performance presumably by changing the morphology of low-k materials.

The effect of porogen on physical properties in MTMS–BTMSE spin-on organosilicates

Decreasing the circuit dimensions is driving the need for low-k materials with a lower dielectric constant to reduce RC delay, crosstalk, and power consumption. In case of spin-on organosilicate low-k films, the incorporation of a porogen is regarded as the only foreseeable route to decrease dielectric constant of 2.2 or below by changing a packing density. In this study, methyltrimethoxysilane (MTMS)–bis(trimethoxysilyl)ethane (BTMSE) copolymers that had superior mechanical properties than MSSQ (methyl-silsesquioxane) were blended with amphiphilic block copolymers used as sacrificial pore generators. While adding up to 40 wt.% porogen into MTMS:BTMSE = 100:50 matrix, optical, electrical, and mechanical properties were measured and the pore structure was also characterized by positron annihilation lifetime spectroscopy (PALS). The result confirmed that there existed a tradeoff in attaining the low dielectric constant and desirable mechanical strength, and no more pores than necessary to achieve the dielectric objective should be incorporated. When the dielectric constant was fixed to approximately 2.3 by controlling BTMSE and porogen contents simultaneously, the thermo-mechanical properties of the porous films were also investigated for the comparison purpose. Under the same dielectric constant, the concurrent increase in BTMSE and porogen contents led to improvement in modulus measured by the nanoindentation technique but deterioration of adhesion strength obtained by the modified edge lift-off test.

Physical properties of low-k films based on the co-condensation of methyltrimethoxysilane with a bridged silsesquioxane

Though spin-on organosilicates are considered as the promising candidates of low dielectric constant materials, it is necessary for a successful integration to improve mechanical strength such as modulus and fracture toughness. In this study, five sets of MTMS–BTMSE copolymers were synthesized and characterized while the monomer content of BTMSE (bis(trimethoxysilyl)ethane) was varied from 9.1 to 47.3 mol% vs. MTMS (methyltrimethoxysilane). In parallel with the measurement of dielectric constant, four different tests were carried out to evaluate mechanical properties of the MTMS–BTMSE copolymers. Modulus was measured by the nanoindentation technique and the modified edge lift-off test (MELT) was employed to extract adhesive fracture toughness quantitatively. In addition, residual stress was calculated by sensing the change in radius of curvature of the substrate. The chemical structure of the copolymers was also analyzed with FTIR and NMR. Network formation was enhanced as the amount of BTMSE increased, which led to improvement of modulus and the increase in refractive index and dielectric constant. However, an increasing rate of fracture toughness by the MELT was not proportional to the increase in the amount of BTMSE, which implied that it was necessary to optimize the composition of the copolymers since adhesion strength was conjectured the most critical factor for a successful integration.

Muscle Strain of the Subscapularis Muscle: A Case Report

We report on a case of muscle strain of the subscapularis muscle in a baseball player. An out-fielder (throws right-handed and bats left-handed) hurt his right shoulder while playing baseball. He complained of right-shoulder pain just after he forcefully hit his right hand against the fence in an attempt to jump and catch a flying ball with a glove on the left hand during a baseball game. Fat-suppressed T2-weighted magnetic resonance images (MRIs) of the right shoulder joint revealed muscle strain in the middle part of the subscapularis muscle, and the injury was surmised to have occurred on account of eccentric contraction of the subscapularis muscle. The case was considered to have moderate muscle strain, because he had modest muscle weakness with a negative lift-off test. Active stretching exercises were begun just after his first visit to our clinic, and throwing exercises were started 3 weeks later, by when the right-shoulder pain had completely disappeared. Repeat MRIs of the right shoulder joint obtained 4 weeks after his first visit to our clinic revealed a significant reduction of the high-intensity lesions in the subscapularis muscle. Conservative treatment was effective for managing moderate muscle strain of the subscapularis muscle. Muscle strain of the subscapularis muscle should be taken into consideration in the differential diagnosis of shoulder injuries in athletes.

The Bear-Hug Test: A New and Sensitive Test for Diagnosing a Subscapularis Tear

It was our intent to devise a new clinical test that would more accurately diagnose subscapularis tears than the current clinical tests. This new test is called the bear-hug test. The purpose of this study was to assess the bear-hug test and compare it with the current tests of subscapularis function (lift-off, belly-press, and Napoleon tests). Between January 2004 and March 2004, 68 consecutive patients scheduled for an arthroscopic procedure were evaluated preoperatively; the preoperative clinical examination findings were then correlated with arthroscopic findings. Lift-off, belly-press, Napoleon, and bear-hug tests were included in the examination. Furthermore, for the belly-press and bear-hug tests, the strength was precisely quantified by means of an electronic digital tensiometer (Kern HBC). Diagnostic arthroscopy was the reference that determined the actual pathologic lesions. Subscapularis tears occurred with a prevalence rate of 29.4%. Of the subscapularis tears, 40% were not predicted by preoperative assessment by use of all of the tests. The bear-hug test was found to be the most sensitive test (60%) of all of those studied (belly-press test, 40%; Napoleon test, 25%; and lift-off test, 17.6%). In contrast, all 4 tests had a high specificity (lift-off test, 100%; Napoleon test, 97.9%; belly-press test, 97.9%; and bear-hug test, 91.7%). No statistically significant difference was found between the area under the receiver operating characteristic curve of the bear-hug test and that of the belly-press test in diagnosing a torn subscapularis. However, the areas under the receiver operating characteristic curve for both the bear-hug test and the belly-press test were significantly greater than those for the lift-off and Napoleon tests (P < .05). Positive bear-hug and belly-press tests suggest a tear of at least 30% of the subscapularis, whereas a positive Napoleon test indicates that greater than 50% of the subscapularis is torn. Furthermore, a positive lift-off test is not found until at least 75% of the subscapularis is torn. The bear-hug test optimizes the chance of detecting a tear of the upper part of the subscapularis tendon. Moreover, because the bear-hug test represents the most sensitive test, it can be considered to be the most likely clinical test to alert the surgeon to a possible subscapularis tear. Performing all of the subscapularis tests is useful in predicting the size of the tear. Level I, diagnostic study: testing of previously developed criteria in a series of consecutive patients with arthroscopy used as the criterion standard.

Lesser Tuberosity Osteotomy for Total Shoulder Arthroplasty

Recent studies have suggested that tenotomy and repair of the subscapularis tendon carried out for anterior approaches to the shoulder can be followed by failure of the tendon repair and by changes resulting in permanent loss of subscapularis function. We hypothesized that release of the subscapularis with use of a superficial osteotomy of the lesser tuberosity followed by repair of the two opposing bone surfaces would lead to consistent bone-to-bone healing, which would be possible to monitor radiographically, and would lead to satisfactory clinical and structural outcomes. Thirty-nine shoulders in thirty-six consecutive patients who, at an average age of fifty-seven years, had undergone total shoulder replacement through an anterior approach involving an osteotomy of the lesser tuberosity were evaluated at an average of thirty-nine months. Assessment included a standardized interview and physical examination, scoring according to the system described by Constant and Murley, and imaging with conventional radiography and computed tomography to assess healing of the osteotomy site and changes in the subscapularis. The osteotomized tuberosity fragment healed in an anatomical position in all shoulders, and no cuff tendon ruptures were observed. At the time of follow-up, thirty-three (89%) of thirty-seven shoulders evaluated with a belly-press test had a negative result and twenty-seven (75%) of thirty-six shoulders evaluated with a lift-off test had an unequivocally normal result. Fatty infiltration of the subscapularis muscle increased after the operation (p < 0.0001) and was at least stage two in eleven (32%) of thirty-four shoulders. The fatty infiltration had progressed by one stage in eight (24%) of the thirty-four shoulders, by two stages in five shoulders (15%), and by three stages in two shoulders (6%). Osteotomy of the lesser tuberosity provides an easy anterior approach for total shoulder replacement and is followed by consistent bone-to-bone healing, which can be monitored, and good subscapularis function. In the presence of documented anatomical healing of the osteotomy site, postoperative fatty infiltration of the subscapularis muscle remains unexplained and needs to be investigated further as it is associated with a poorer clinical outcome.

Accurate cable force determination using ambient vibration measurements

Knowledge of the tensile forces in cables of bridges or in external tendons is required for regular inspection and safety assessments. Force determination by lift-off tests with hydraulic jacks can result in considerable expenditure as well as the danger of damage. However, alternatively conducted vibration measurements have shown that, due to improper identification of natural frequencies or the use of over-simple force–frequency relationships, accuracies achieved up to now are sometimes not achieved. For high cable forces and short cables, errors of up to ±10% could be realized. Fast and accurate methods for assessing cable forces are thus required. The main target of this paper is the presentation of a practical applicable procedure to determine cable forces in civil engineering constructions by means of vibration measurements. By taking into account the identified natural frequencies, the bending stiffness and the boundary conditions, accuracy in the range of ±1% may be achieved.

Are Pain Location and Physical Examinations Useful in Locating a Tear Site of the Rotator Cuff?

Background Pain is the most common symptom of patients with rotator cuff tendinopathy, but little is known about the relationship between the site of pain and the site of cuff pathologic lesions. Also, accuracies of physical examinations used to locate a tear by assessing the muscle strength seem to be affected by the threshold for muscle weakness, but no studies have been reported regarding the efficacies of physical examinations in reference to their threshold. Hypothesis Pain location is useful in locating a tear site. Efficacies of physical examinations to evaluate the function of the cuff muscles depend on the threshold for muscle weakness. Study Design Case series; Level of evidence, 4. Methods The authors retrospectively reviewed the clinical charts of 160 shoulders of 149 patients (mean age, 53 years) with either rotator cuff tears (140 shoulders) or cuff tendinitis (20 shoulders). The location of pain was recorded on a standardized form with 6 different areas. The diagnostic accuracies of the following tests were assessed with various thresholds for muscle weakness: supraspinatus test, the external rotation strength test, and the lift-off test. Results Lateral and anterior portions of the shoulder were the most common sites of pain regardless of existence of tear or tear location. The supraspinatus test was most accurate when it was assessed to have positive results with the muscle strength less than manual muscle testing grade 5, whereas the lift-off test was most accurate with a threshold less than grade 3. The external rotation strength test was most accurate with a threshold of less than grade 4+. Conclusion The authors conclude that pain location is not useful in locating the site of a tear, whereas the physical examinations aiming to locate the tear site are clinically useful when assessed to have positive results with appropriate threshold for muscle weakness.