Nobutoshi Seki

Contact Area, Contact Pressure, and Pressure Patterns of the Tendon-Bone Interface After Rotator Cuff Repair

Background The contact pressure and contact area at the tendon-bone interface after the most commonly used rotator cuff repair methods have not been investigated. Hypothesis There are no significant differences among the transosseous, the single-row suture anchor, and the double-row suture anchor techniques in terms of contact pressure, contact area, and pressure patterns at the tendon-bone interface. Study Design Controlled laboratory study. Methods After creating a full-thickness supraspinatus tendon tear in 10 cadaveric shoulder specimens, we inserted pressure-sensitive film between the tendon stump and the bone, and we repaired the tear by (1) transosseous, (2) single-row suture anchor, and (3) double-row suture anchor techniques. Results The contact area of the double-row technique was 42% greater than that of the transosseous technique (P <. 0001) and 60% greater than that of the single-row technique. The contact area of the transosseous technique was 31% greater than that of the single-row technique (P =. 0015). The average pressures of the single-row and double-row techniques were 18% (P =. 014) and 16% (P =. 03) greater, respectively, than that of the transosseous technique, but there was no significant difference between the single-row and double-row techniques (P =. 915). Conclusions The double-row technique produced the greatest contact area and the second-highest contact pressure, whereas the single-row technique created the highest contact pressure and the least contact area. The transosseous technique produced the second-greatest contact area and the least contact pressure. Clinical Relevance The double-row suture anchor technique and the transosseous technique may provide a better environment for tendon healing.

Prevalence of symptomatic and asymptomatic rotator cuff tears in the general population: From mass-screening in one village.

PURPOSE Rotator cuff tear is the most common shoulder disease in patients with shoulder problems, but its prevalence is not well known. METHODS We performed a health care check-up of locomotive organs in 664 residents (21.3% of the population) in one village. Ultrasonography on bilateral shoulders was performed in all the participants. RESULTS One hundred and forty seven out of 664 subjects (22.1%) had full-thickness rotator cuff tears. The prevalence of tear in each decade was 0% in the 20s to 40s, 10.7% in the 50s, 15.2% in the 60s, 26.5% in the 70s, and 36.6% in the 80s. Symptomatic rotator cuff tears accounted for 34.7% of all tears and asymptomatic tears for 65.3%. The prevalence of asymptomatic rotator cuff tears was one-half of all tears in the 50s, whereas it accounted for two-thirds of those over the age of 60. The prevalence of tear was significantly greater in male than in female in the 50s and 60s, but not in the 70s and 80s. CONCLUSION The prevalence of rotator cuff tear in the general population was 22.1%, which increased with age. Asymptomatic tear was twice as common as symptomatic tear.

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.

Scapular inclination and glenohumeral joint stability: a cadaveric study

BackgroundIn shoulders with multidirectional instability, translation of the humeral head on the glenoid is increased in the midrange because of the following three reasons: the increased retroversion, a hypoplastic posteroinferior rim, and decreased scapular abduction during arm elevation. This study aimed to clarify the relationship between glenoid inclination and glenohumeral joint stability.MethodsNine fresh-frozen cadaveric shoulders were tested. With a 50-N compressive load, the translation force was measured in the 3-o’clock, 6-o’clock, 9-o’clock, and 12-o’clock directions by using a tilt of 0°, 5°, 10°, 15°, and 20°. When the glenoid was tilted in one direction, the translation force was measured in the direction of inclination and in the opposite direction. The stability ratio was then calculated.ResultsThe stability ratio in the 3-o’clock direction significantly decreased with a tilt of more than 5° in the 3-o’clock direction. The stability ratio in the 9-o’clock direction significantly decreased with a tilt of more than 15° in the 9-o’clock direction and significantly increased with a tilt of more than 5° in the 3-o’clock direction. The stability ratio in the 6-o’clock direction significantly increased with a tilt of more than 10° in the 6-o’clock direction.ConclusionsThe posterior and inferior stability increased with an anterior tilt of more than 5° and with a superior tilt of 10°, respectively. The anterior and posterior stability decreased with an anterior tilt of 5° and with a posterior tilt of 15°, respectively.

Cross-sectional area of the tendon and the muscle of the biceps brachii in shoulders with rotator cuff tears: A study of 14 cadaveric shoulders

Background The intraarticular portion of the long head of the biceps tendon is often widened in shoulders with cuff tears. It is unclear whether this is a local phenomen or is caused by muscle hypertrophy. Methods We investigated morphological changes of the biceps brachii in 14 embalmed shoulders: 7 with intact rotator cuff and 7 with rotator cuff tears. We measured the cross-sectional area (CSA) of the tendon of the long head of the biceps (LHB) at 9 levels between the glenoid origin and the musculotendinous junction. The muscle volume and the muscle fiber length of the long and short heads of the biceps were measured to calculate the physiological CSA (PCSA) by dividing the volume by the fiber length. Results The CSA of the LHB tendon at the entrance to the bicipital groove was greater in cuff tear shoulders than in normal shoulders. The PCSA of the biceps was similar in normal and cuff tear shoulders. Interpretation Hypertrophy of the LHB tendon appears to be a localized morphological change near the entrance to the bicipital groove.

The Effect of the Inferior Capsular Shift on Shoulder Intra-articular Pressure A Cadaveric Study

Background The inferior capsular shift procedure is commonly performed for multidirectional instability of the shoulder with excellent clinical results. Hypothesis The mechanism of this procedure is to increase shoulder stability by changing the responsiveness of intra-articular pressure to downward loading. Study Design Controlled laboratory study. Methods In 7 fresh-frozen cadaveric shoulders, inferior capsular shift was simulated by imbricating the anterior and posterior capsule using clamps. The position was monitored using an electromagnetic tracking device with the glenohumeral joint capsule intact, imbricated anteriorly, or imbricated anteriorly and posteriorly and with the inferior load of 0, 0.5, or 1.0 kg. Simultaneously, intra-articular pressure was monitored using a pressure transducer. Saline was injected into the glenohumeral joint to measure capsular volume. The capsule was vented, and the position was again measured. Results Intra-articular pressure was –71 ± 19, –221 ± 70, and –366 ± 73 cm H2O with 0, 0.5, and 1.0 kg of load, respectively, with the capsule intact. With anterior imbrication, intra-articular pressure decreased to –79 ± 10, –274 ± 103, and –460 ± 135 cm H2O, respectively, and with anterior and posterior imbrication, intra-articular pressure further decreased to –87 ± 16, –308 ± 74, and –548 ± 39 cm H2O, respectively. The volume of the intact shoulder (36 ± 9 mL) significantly decreased to 27 ± 7 mL (75%) with anterior imbrication and to 15 ± 5 mL (42%) with anterior and posterior imbrications (P = .0001). Before venting the capsule, inferior displacement was 5% of the vertical length of the glenoid, even with 1.0 kg of load with any capsular conditions. After venting, the humeral head dislocated inferiorly in all shoulders, even after imbrications. Conclusion The inferior capsular shift procedure decreases joint volume and increases responsiveness of intra-articular pressure to downward loading. Clinical Relevance Biomechanical data provide scientific background to the commonly performed procedures of inferior capsular shift and thermal capsular shrinkage.

Mechanical environment of the supraspinatus tendon: three-dimensional finite element model analysis

BackgroundWe analyzed the mechanical environment of the supraspinatus tendon using a three-dimensional finite element model with the software programs MENTAT and MARC.MethodsThe supraspinatus tendon that attaches to the superior facet was extracted and modeled. The geometric shape of the humeral head was determined from computed tomography images, and the shape of the supraspinatus tendon was determined from magnetic resonance images of the shoulder at 0° of abduction in a healthy 27-year-old man. The distal portion of the humeral head was fixed, and 10 N of tensile force was applied to the proximal end of the tendon. The tensile stress was calculated.ResultsThe tensile stress was 1.8 MPa for the bursal side and 15.0 MPa for the articular side of the anterior portion of the supraspinatus tendon. The intensity was 0 MPa for the bursal side and 4.5 MPa for the articular side of the middle portion of the tendon. The intensity was 0.1 MPa for the bursal side and 5.2 MPa for the posterior edge of the tendon.ConclusionsBased on the three-dimensional finite element method, the maximal tensile stress was observed on the articular side of the anterior edge of the supraspinatus tendon. Our result may explain the frequent occurrence of rotator cuff tears at this site.

Objective Evaluation of Shoulder Pain by Measuring Skin Impedance

The subjective nature of pain has made its objective evaluation rather difficult. Recently, skin impedance was reported to reflect pain. The purpose of this study was to determine the usefulness of measuring skin impedance in evaluating shoulder pain. Fifty-three patients with shoulder pain were examined. Skin impedance was measured by a skin impedance meter in three different conditions and was compared with the visual analog scale recorded at the same time.

Clinical diagnosis of upper lumbar disc herniation: Pain and/or numbness distribution are more useful for appropriate level diagnosis

OBJECTIVE The purpose of this study is to disclose the characteristic symptoms and signs in L2, L3 and L4 nerve root disturbance. MATERIALS AND METHODS Fifty eight patients who underwent lateral herniotomy were analyzed. Breakdowns are 15 patients with L2/3 lateral disc herniation (group A), 20 patients with L3/4 lateral disc herniation (group B), and 23 patients with L4/5 lateral disc herniation (group C). The following items were examined: 1) localization of the subjective pain and numbness, 2) objective neurological findings, including deep tendon reflex, manual muscle strength (MMT), straight leg raising test (SLRT) and femoral nerve stretch test (FNST). RESULTS In group A, subjective pain and/or numbness was present in the thigh aspect, proximal to the knee joint in all patients. In group B, 80% of the patients had subjective pain and/or numbness in the medial site of the knee joint. In group C, the subjective pain and/or numbness was localized in various aspects of the lower extremity. Weakness in the iliopsoas, the femoral quadriceps, and the anterior tibial muscle were observed in 60-95%, 27-70%, 0-43% of three groups, respectively. Depression or absence of the patella tendon reflex was present in 27-100% of three groups. SLRT and FNST were positive in 13-87% and 91-95% of three groups. CONCLUSION Symptomatic levels of nerve root disturbance in the upper lumbar spine could not be accurately identified by objective neurological findings alone. Pain and/or numbness localized in the thigh area proximal to the knee joint is a specific sign of L2 nerve root disturbance. Either subjective pain or numbness in the medial knee joint aspect is another key sign which strongly suggests L3 nerve root disturbance.

Osteolysis of the Greater Trochanter Caused by a Foreign Body Granuloma Associated with the Ethibond® Suture after Total Hip Arthroplasty

The present case shows a case of progression of osteolysis of the greater trochanter caused by a foreign body granuloma associated with the number 5 Ethibond suture in cementless THA with the direct lateral approach that was completely healed by removal of the Ethibond suture. A 55-year-old Japanese woman with secondary osteoarthritis caused by acetabular dysplasia underwent left cementless THA with the direct lateral approach. After setting of the total hip prosthesis, the gluteus medius muscle and vastus lateralis muscle were reattached to the greater trochanter through two bone tunnels using number 5 Ethibond EXCEL sutures. The left hip pain disappeared after surgery, but the bone tunnels enlarged gradually and developed osteolysis at 10 weeks. The removal of the Ethibond sutures and debridement improved the osteolysis. Histological examination showed the granuloma reaction to a foreign body with giant cell formation. The Ethibond suture has the lowest inflammatory tissue reaction and relatively high tension strength among nonabsorbable suture materials. However, number 5 Ethibond has the potential to cause osteolysis due to a foreign body granuloma, as in the present case.