Tendon Insertion Site Research Articles

Magnetic Resonance Imaging in Adolescent Painful Flexible Flatfoot

The cause of navicular tuberosity pain in adolescents with flexible flatfeet is not well understood. We hypothesized that some of the navicular tuberosity pain may be related to insertional enthesopathy of the posterior tibial tendon at the navicular. Magnetic resonance imaging was performed to look for abnormal signal changes in a series of patients. Consecutive adolescent patients presenting with flexible flatfeet and navicular tuberosity pain were prospectively recruited. A detailed foot examination and body fat analysis was performed. Standing radiographs and Tekscan pedobarograph of both feet were obtained. Magnetic resonance examinations were performed on a 1.5-T whole-body magnetic resonance imaging system utilizing a standard extremity coil. MRI abnormality was detected in 15 of the 36 feet in 18 adolescents examined. Abnormalities detected included thickening of the posterior tibial tendon insertion, marrow edema in the accessory navicular, marrow edema in the navicular tuberosity, and contrast enhancement at the posterior tibial tendon insertion site. Patients with MRI abnormalities were significantly taller, had a lower body mass index and a lower body fat percentage than those without MRI abnormality. Forward stepwise logistic regression analysis identified low body fat percentage and presence of an accessory navicular as independent predictors for abnormality on MRI. MRI abnormality was frequently detected in adolescents with painful flexible flatfeet. The MRI signal changes indicated an enthesopathy like process occurring at the posterior tibial tendon insertion to the navicular which could explain the origin of pain in flexible flatfeet patients without an accessory navicular. Early identification and appropriate treatment to prevent progression may be helpful.

회전근 개 파열의 병리 생태학에서의 논쟁점: 퇴행성 파열

The pathophysiology of rotator cuff tears and the progression of asymptomatic tears to symptomatic tears are yet unclear and much controversy. It is likely to involve a number of factors such as a genetic predisposition, extrinsic impingement from structures surrounding the cuff and intrinsic degeneration from changes within the tendon itself. Degenerative changes in the rotator cuff with aging seem to be related to the anatomic and mechanical environment of the rotator cuff. The histopathologic appearance of rotator cuff tendon rupture specimens demonstrates a consequence of degenerative changes at the site of tendon insertion into bone. It weakens the tensile strength of the tendon. Is the process of degeneration intrinsic or extrinsic in nature? I suggest that degeneration is intrinsic and not caused by extrinsic factors. Even though, rotator cuff tear may be secondary to multiple factors, I believe that primary cause of rotator cuff tears is preexisting degenerative change.

R435 – Stapedius Muscle Relations to the Facial Canal

Problem The gross anatomical variations of the stapedius muscle and its relations to the facial nerve canal. Methods Thirty-five temporal bones were dissected, and the anatomic details were studied utilizing an operating microscope and otoendoscopes with 0o, 30o and 70o angles and 2.7 and 3 mm diameters. The muscle origin, its course in its bony sulcus with its relation to the facial nerve canal, the tendon and its insertion were studied. Results Marked variations in the origin, size, and course of the muscle in its bony sulcus were detected. The shape of the sulcus itself and its relation to the facial nerve canal varied also, both mainly influenced by the sinus tympani development. These variations affected the shape and length of the tendon and the pyramidal eminence. In addition, they influenced the site of tendon insertion into the stapes. The presence of ectopic muscle bundles was confirmed in one specimen. Conclusion The stapedius muscle anatomy can vary significantly from one temporal bone to another. In some situations these variations can be of surgical importance worse enough to be recognized. Significance To add important unrecognized data to the surgical anatomy of the temporal bone.

Single-Row Suture Anchor Repair of the Rotator Cuff is Biomechanically Equivalent to Double-Row Repair in a Bovine Model

The purpose of this study was to determine biomechanical differences in cyclic elongation and ultimate strength between double-row rotator cuff repair and single-row repair for partial rotator cuff repairs. We randomly assigned 18 immature bovine specimens (aged 12 to 16 weeks) to 3 repair groups (6 per group). A 1 x 2-cm defect was created at the infraspinatus tendon insertion site. Two suture anchors were implanted 1 cm apart at the anatomic insertion area for the lateral row. Two suture anchors were implanted 1 cm medial to the lateral row and 1 cm apart from each other for the medial row. Repair groups were constructed as follows: single-row repair with double-loaded suture anchors (group 1), double-row repair with single-loaded medial row and double-loaded lateral row (group 2), and double-row repair with single-loaded medial row and single-loaded lateral row (group 3). Specimens were cyclically loaded from 10 N to 90 N for 500 cycles and then loaded at 0.5 mm/s to failure. Data for cyclic elongation, with loads at 3 mm, 5 mm, and 10 mm, were analyzed via a 1-way analysis of variance (P < .05). There were no significant differences for peak elongation after cyclic loading between groups. There were no significant differences between repair groups for loads at 3 mm, 5 mm, and 10 mm of elongation. Constructs typically failed by knot slippage (83%), with a single sample having tendon-suture failure (17%). Double-row repair did not show a biomechanical advantage compared with single-row repair. With this result in mind, the theoretic advantage of a potentially larger footprint must be balanced against the added surgical time, complexity, and cost of double-row repair. Arthroscopic surgeons should choose the best form of fixation for a given patient, without undue emphasis on single-row repair versus double-row repair. The clinical and biologic impact of footprint restoration was not addressed in this study.

Mechanical regulation of PTHrP expression in entheses

The PTHrP gene is expressed in the periosteum and in tendon and ligament insertion sites in a PTHrP-lacZ knockin reporter mouse. Here, we present a more detailed histological evaluation of PTHrP expression in these sites and study the effects of mechanical force on PTHrP expression in selected sites. We studied the periosteum and selected entheses by histological, histochemical, and in situ hybridization histochemical techniques, and tendons or ligaments were unloaded by tail suspension or surgical transection. In the periosteum, PTHrP is expressed in the fibrous layer and the type 1 PTH/PTHrP receptor (PTH1R) in the subjacent cambial layer. PTHrP has distinct temporospatial patterns of expression in the periosteum, one hot spot being the metaphyseal periosteum in growing animals. PTHrP is also strongly expressed in a number of fibrous insertion sites. In the tibia these include the insertions of the medial collateral ligament (MCL) and the semimembranosus (SM). In young animals, the MCL and SM sites display a combination of underlying osteoblastic and osteoclastic activities that may be associated with the migration of these entheses during linear growth. Unloading the MCL and SM by tail suspension or surgical transection leads to a marked decrease in PTHrP/lacZ expression and a rapid disappearance of the subjacent osteoblastic population. We have not been able to identify PTHrP-lacZ in any internal bone cell population in the PTHrP-lacZ knockin mouse in either a CD-1 or C57Bl/6 genetic background. In conclusion, we have identified PTHrP expression in surface structures that connect skeletal elements to each other and to surrounding muscle but not in intrinsic internal bone cell populations. In these surface sites, mechanical force seems to be an important regulator of PTHrP expression. In selected sites and/or at specific times, PTHrP may influence the recruitment and/or activities of underlying bone cell populations.

Abduction and External Rotation in Shoulder Impingement: An Open MR Study on Healthy Volunteers—Initial Experience

To prospectively evaluate rotator cuff contact with the glenoid in healthy volunteers placed in the unloaded and loaded abduction and external rotation (ABER) positions in an open magnetic resonance (MR) imager. The study was institutional review board approved and HIPAA compliant, and informed consent was received. Eight male volunteers with no history of shoulder pain or pathology were imaged in a 0.5-T open MR imager. Volunteers were imaged in an unloaded ABER position with the arm at 90 degrees abduction and in a loaded ABER position, with a 1-kg load that produced an average external rotation of 111 degrees+/-6 (standard deviation). Two radiologists graded rotator cuff contact on a three-point scale. Three-dimensional anatomic models generated from the MR images were used to measure distances. Minimum distances were computed between the tendon insertion sites and the glenoid, acromion, and coracoid for the loaded ABER position. Minimum distances were compared by using a paired Student t test. In the unloaded ABER position, contact was seen between the infraspinatus and supraspinatus tendons and the glenoid in all eight volunteers. In the loaded ABER position, contact was also observed between the infraspinatus and supraspinatus and the posterior and posterosuperior glenoid, respectively. Deformation of the infraspinatus on the glenoid was seen in four volunteers, whereas supraspinatus deformation was only seen in one volunteer. The minimum distance between the supraspinatus insertion and acromion in the loaded ABER position decreased significantly (P<.01). Supraspinatus tendon to glenoid and infraspinatus tendon to glenoid minimum distances also decreased significantly (P<.01). The unloaded and loaded ABER positions resulted in contact of the supraspinatus and infraspinatus with the glenoid in all volunteers. Distances between the rotator cuff insertion sites and the glenoid decreased in the loaded ABER position.

Cystic Changes at Supraspinatus and Infraspinatus Tendon Insertion Sites: Association with Age and Rotator Cuff Disorders in 238 Patients

To retrospectively determine the frequency of posterior and anterior cystic abnormalities at rotator cuff insertion site on the greater tuberosity and to determine their relationship to patient age and rotator cuff disorders. Institutional review board approval was given; informed consent was waived. The study was HIPAA compliant. In 238 patients with rotator cuff diagnoses at surgery, preoperative magnetic resonance (MR) imaging studies were reviewed to localize osseous cystic changes as anterior (supraspinatus insertion site) or posterior (infraspinatus insertion site) on the greater tuberosity. If rotator cuff tear was present, tendon retraction and location of partial tear (articular or bursal surface) were recorded. Two radiologists reached conclusions by consensus. Locations of cysts were correlated to surgical cuff diagnoses: no tear, tendinopathy, partial-thickness tear, and complete tear. Prospective interpretations from original MR reports were compared with surgical results. Statistical analyses included one-way analysis of variance, chi(2), Fisher exact, and Student t tests, as well as logistic regression and receiver operating characteristic curve comparison. There were 238 consecutive patients (150 men, 88 women; mean age, 43 years). Cysts were located at or near footprint of cuff tendon and demonstrated fluid or soft-tissue signal intensities. Posterior cysts occurred in 56.7% of shoulders and showed no statistical correlation to age or cuff diagnosis. Anterior cysts occurred in 22.7% of shoulders and were strongly associated with cuff disorders (P<.001). Controlling for cuff disorders, there was no relationship between anterior cysts and age (P>.50). Anterior cysts were more common in partial-thickness articular (48%) than in bursal (13%) tears (P<.001). Posterior cysts were more common than anterior cysts and showed nearly random distribution among patients, regardless of age and cuff diagnosis. Anterior cysts were closely associated with cuff disorders.

Pathogenesis of Tendon Rupture Secondary to Fluoroquinolone Therapy

Tendon rupture related to trauma and corticosteroid injection, in and about tendon insertion sites, is well documented in the literature. Rupture of tendon after fluoroquinolone therapy has been identified in the recent past. Both short- and long-term courses of antibiotic treatment with fluoroquinolone may precipitate alteration in tendon matrix leading to tendinopathy with subsequent rupture. The pathogenesis of tendon rupture secondary to fluoroquinolone therapy is presented.

The Role of Bone Morphogenetic Proteins in Rotator Cuff Tendon Repair

Summary: Bone morphogenetic proteins are multi-functional molecules that play an important role in tissue differentiation. The classic BMPs (BMP-2, 4, 7) are osteoinductive, whereas more recently described BMPs (BMP-12, 13) are expressed during tendon insertion site formation in embryogenesis and have been found to induce formation of fibrocartilage. This review examines several studies that have tested the effects of bone morphogenetic proteins in rotator cuff tendon repair models.

Alendronate prevents bone loss and improves tendon‐to‐bone repair strength in a canine model

Previously we showed a loss of bone and a concomitant decrease in mechanical properties in the first 21 days after flexor tendon insertion site injury and repair in a canine model. The goal of this short-term study was to suppress bone loss after insertion site repair using alendronate in an attempt to prevent the reduction in biomechanical properties. Flexor tendons of the second and fifth digits of the right forelimbs of canines were injured and repaired. Dogs received a daily oral dose of alendronate (2 mg/kg). One digit in each dog also received a local dose of alendronate in the bone tunnel at the time of surgery. The repair was evaluated for bone mineral density (BMD) and biomechanical properties and compared to data from a previous study in which no alendronate was used. Alendronate was effective in protecting the distal phalanx from resorption during tendon-to-bone healing (BMD was 94 and 104% of control for systemic alendronate and for systemic plus local alendronate, respectively). Alendronate treatment prevented much of the decrease in ultimate load that occurs in the first 21 days. Without treatment, ultimate load was 42% of control. With systemic alendronate treatment and systemic plus local alendronate treatment, ultimate load was 78 and 69% of control, respectively. Failure mode was significantly different when comparing alendronate treatment to repair alone. A lower incidence of suture pull through was found in alendronate treated dogs, suggesting less tendon degeneration. Ultimate load can be improved in association with preventing the bone loss that normally occurs during the early period following tendon-to-bone repair. These initial short-term data demonstrate the potential for a clinical treatment that could enhance tendon-to-bone healing.

Long Durations of Immobilization in the Rat Result in Enhanced Mechanical Properties of the Healing Supraspinatus Tendon Insertion Site

Rotator cuff tears frequently occur and can lead to pain and decreased shoulder function. Repair of the torn tendon back to bone is often successful in relieving pain, but failure of the repair commonly occurs. Post-operative activity level is an important treatment component that has received minimal attention for the shoulder, but may have the potential to enhance tendon to bone healing. The objective of this study was to investigate the effect of short and long durations of various activity levels on the healing supraspinatus tendon to bone insertion site. Rotator cuff tears were surgically created in Sprague-Dawley rats by detaching the supraspinatus tendon from its insertion on the humerus and these tears were immediately repaired back to the insertion site. The post-operative activity level was controlled through shoulder immobilization (IM), cage activity (CA), or moderate exercise (EX) for durations of 4 or 16 weeks. The healing tissue was evaluated utilizing biomechanical testing and a quantitative polarized light microscopy method. We found that activity level had no effect on the elastic properties (stiffness, modulus) of the insertion site at four weeks post injury and repair, and a decreased activity level had a positive effect on these properties at 16 weeks (IM>CA=EX). Furthermore, a decreased activity level had the greatest positive effect on these properties over time (IM>CA=EX). The angular deviation of the collagen, a measure of disorganization, was decreased with a decrease in activity level at 4 weeks (IM<CA=EX), but was similar between groups at 16 weeks (IM=CA=EX). It appears from this study that decreasing the activity level by immobilizing the shoulder improves tendon to bone healing, which progresses by first increasing the organization of the collagen and then increasing the mechanical properties. Future studies in this area will investigate the effect of passive motion and remobilization on both tendon to bone healing and shoulder function.

Rupture of the Anterior Tibial Tendon: Three Clinical Cases, Anatomical Study, and Literature Review

We report three cases of anterior tibial tendon ruptures and the results of an anatomical study in regard to the tendon's insertion site and a literature review. Three patients were referred to our hospital with anterior tibial tendon ruptures. In the anatomical study, 53 feet were dissected, looking in particular for variants of the bony insertion of the tendon. Two patients had surgical treatment (one primary repair and one semimembranosus tendon graft) and one conservative treatment. After a mean followup of 14 weeks all patients had satisfactory outcomes. In the anatomical study, we noted three different insertion sites: in 36 feet the tendon inserted into the medial side of the cuneiform and the base of the first metatarsal bone and in 13 feet only into the medial side of the cuneiform bone. In the remaining four feet the tendon inserted into the cuneiform and the first metatarsal bone, but an additional tendon was noted taking its origin from the anterior tibial tendon near its insertion into the medial cuneiform and attaching to the proximal part of the first metatarsal. According to literature, surgical repair is the treatment of choice for acute ruptures and for patients with high activity levels. For chronic ruptures and patients with low demands, conservative management may lead to an equally good outcome. Knowledge of the anatomy in this region may be helpful for diagnosis and for the interpretation of intraoperative findings and choosing the most appropriate surgical procedure.

Early healing of flexor tendon insertion site injuries: Tunnel repair is mechanically and histologically inferior to surface repair in a canine model

Orthopedic injuries often require surgical reattachment of tendon to bone. Tendon ends can be sutured to bone by direct apposition to the bone surface or by placement within a bone tunnel. Our objective was to compare early healing of a traditional surface versus a novel tunnel method for repair of the flexor digitorum profundus (FDP) tendon insertion site in a canine model. A total of 70 tendon-bone specimens were analyzed 0, 5, 10 or 21 days after injury and repair, using tensile and range of motion mechanical testing, histology and densitometry. Ultimate force (a measure of repair strength) did not differ between surface and tunnel repairs at day 0. Both repair types had reduced strength at 10 and 21 days compared to 0 days, indicative of deterioration of suture grasping strength (tendon softening). At 21 days, tendons repaired in a bone tunnel had 38% lower ultimate force compared to surface repairs (p = 0.017). Histological findings were comparable between repair groups at 5 and 10 days but differed at 21 days, when we saw evidence of maturation of the tendon-bone interface in the surface repairs compared to an immature fibrous interface with no evidence of tendon-bone integration in the tunnel repairs. After accounting for bone removed by the tunnel, no difference in bone mineral density or trabecular bone volume existed between surface and tunnel repairs. If the results of our animal study extend to healing of the human FDP insertion, they indicate that FDP tendons should be reattached to the distal phalanx by suture to the cortical surface rather than suture in a bone tunnel.

Extrasynovial ultrasound abnormalities in the psoriatic finger. Prospective comparative power-doppler study versus rheumatoid arthritis

We prospectively compared power Doppler ultrasound findings in 25 fingers with rheumatoid arthritis (RA) and 25 fingers with psoriatic arthritis (PsA). Erosive synovitis and tenosynovitis were seen in both groups. Extrasynovial changes were found in 21/24 (84%) fingers with PsA versus none of the fingers with RA. Of the 21 PsA fingers exhibiting extrasynovial changes, 15 (15/25, 60%) also had synovial changes. The extrasynovial changes reflected enthesitis or soft tissue inflammation, with the main patterns being capsular enthesophyte, juxtaarticular periosteal reaction, enthesopathy at the site of deep flexor tendon insertion on the distal phalanx, and subcutaneous soft tissue thickening of the finger pad or entire finger. In four fingers, ultrasonograhy showed pseudotenosynovitis, an underrecognized abnormality characterized by diffuse inflammation of the digital soft tissues. Pseudotenosynovitis may play a pivotal role in dactylitis (sausage digit), which is defined as diffuse uniform swelling of the entire finger. Our findings suggest that inflammation of the fibrous skeleton of the finger may lead to the clinical and radiological features that distinguish PsA from RA of the finger.

Arthroscopic Patellar Release for the Treatment of Chronic Patellar Tendinopathy

Abstract We describe an arthroscopic technique for the treatment of chronic patellar tendinopathy (jumper’s knee). Preoperatively, tendon necrosis or rupture is excluded by sonography. Diagnostic arthroscopy is performed and hypertrophic synovitis around the inferior patellar pole is removed with a bipolar cautery system. Two outside-in cannulas mark the clinically symptomatic region, mainly found between the tendon insertion site and the lateral aspects of the patellar tendon. The bipolar cautery is used for a release of the paratenon and a bone denervation at the inferior patellar pole including the tendon insertion site within the marked area. No tendon or bone material is removed or excised throughout the procedure. We treated 15 athletes with stage 3 and 4 chronic patellar tendinopathies on a modified version of the Blazina score (0-5). Patients’ mean age was 29 years and the mean follow-up period was 41 months. In 13 cases, clinical symptoms subsided completely within 3 months after surgery. The mean preoperative Blazina score was 3.7 (SD, 0.5) and the mean postoperative Blazina score was 0.4 (SD, 1.0; paired 2-tailed t test, P < .01). Ultrasound showed a reduction of tendon edema within 3 weeks and no signs of edema within a mean period of 5 weeks after surgery. The minimal surgical impact to the tendon allows early and functional rehabilitation. The technique is effective, easy to perform, and safe to apply.

Characteristics of the rat supraspinatus tendon during tendon‐to‐bone healing after acute injury

Rotator cuff repair is known to have a high failure rate. Little is known about the natural healing process of the rotator cuff repair site, hence little can be done to improve the tendon's ability to heal. The purpose of this study was to investigate the collagen formation at the early repair site and to localize TGFbeta-1 and 3 during early healing and compare their levels to cell proliferation and histological changes. Bilateral supraspinatus tendons were transected and repaired in 60 rats. Specimens were harvested and evaluated at 0, 1, 3, 7, 10, 28, and 56 days. Histological sections were evaluated for cell morphology. Immunohistochemistry and in situ hybridization was performed to localize protein and mRNA for collagen types I and III and TGFbeta-1 and 3. Proliferating cell nuclear antigen (PCNA) assay was performed to measure cell proliferation, and cells were counted to determine cell density. Biomechanical properties were evaluated. Repair tissue demonstrated an initial inflammatory response with multinucleated cells present at 1 and 3 days, and lymphocytes and plasma cells presents at 7 and 10 days. Capillary proliferation began at 3 days and peaked at 10 days. Ultimate force increased significantly over the time period studied. Collagen I protein and mRNA significantly increased at 10 days, and reached a plateau by 28 and 56 days. Collagen III showed a similar trend, with an early increase, and remained high until 56 days. TGFbeta-1 was localized to the forming scar tissue and showed a distinct peak at 10 days. TGFbeta-3 was not seen at the healing insertion site. Cell proliferation and density followed the same trend as TGFbeta-1. A wound healing response does occur at the healing rotator cuff insertion site, however, the characteristics of the tendon after healing differ significantly from the uninjured tendon insertion site at the longest time-point studied. A distinctive collagen remodeling process occurred with an initial increase in the formation of collagen types I and III followed by a decrease toward baseline levels seen at time 0. Growth factor TGFbeta-1 was localized to repair tissue and coincided with a peak in cell proliferation and cellularity. Repair sites remained unorganized histologically and biomechanically inferior in comparison to previously described uninjured insertion sites.

Initial Characterization of PTH-Related Protein Gene-Driven lacZ Expression in the Mouse

The PTHrP gene generates low-abundance mRNA and protein products that are not easily localized by in situ hybridization histochemistry or immunohistochemistry. We report here a PTHrP-lacZ knockin mouse in which beta-gal activity seems to provide a simple and sensitive read-out of PTHrP gene expression. PTH-related protein (PTHrP) is widely expressed in fetal and adult tissues, typically as low-abundance mRNA and protein products that maybe difficult to localize by conventional methods. We created a PTHrP-lacZ knockin mouse as a means of surveying PTHrP gene expression in general and of identifying previously unrecognized sites of PTHrP expression. We created a lacZ reporter construct under the control of endogenous PTHrP gene regulatory sequences. The AU-rich instability sequences in the PTHrP 3' untranslated region (UTR) were replaced with SV40 sequences, generating products with lacZ/beta gal kinetics rather than those of PTHrP. A nuclear localization sequence was not present in the construct. We characterized beta-galactosidase (beta-gal) activity in embryonic whole mounts and in the skeleton in young and adult animals. In embryos, we confirmed widespread PTHrP expression in many known sites and in several novel epidermal appendages (nail beds and footpads). In costal cartilage, beta-gal activity localized to the perichondrium but not the underlying chondrocytes. In the cartilaginous molds of forming long bones, beta-gal activity was first evident at the proximal and distal ends. Shortly after birth, the developing secondary ossification center formed in the center of this PTHrP-rich chondrocyte population. As the secondary ossification center developed, it segregated this population into two distinct PTHrP beta-gal+ subpopulations: a subarticular subpopulation immediately subjacent to articular chondrocytes and a proliferative chondrocyte subpopulation proximal to the chondrocyte columns in the growth plate. These discrete populations remained into adulthood. beta-gal activity was not identified in osteoblasts but was present in many periosteal sites. These included simple periosteum as well as fibrous tendon insertion sites of the so-called bony and periosteal types; the beta-gal-expressing cells in these sites were in the outer fibrous layer of the periosteum or its apparent equivalents at tendon insertion sites. Homozygous PTHrP-lacZ knockin mice had the expected chondrodysplastic phenotype and a much expanded region of proximal beta-gal activity in long bones, which appeared to reflect in large part the effects of feedback signaling by Indian hedgehog on proximal cell proliferation and PTHrP gene expression. The PTHrP-lacZ mouse seems to provide a sensitive reporter system that may prove useful as a means of studying PTHrP gene expression.

Spontaneous Rupture of the Patellar and Contralateral Quadriceps Tendons Associated with Secondary Hyperparathyroidism in a Patient Receiving Long-term Dialysis

Although spontaneous rupture of the extensor tendon of the knee is more likely to occur in uremic patients with secondary hyperparathyroidism, simultaneous ruptures of bilateral knee extensor tendons is a rarely reported condition. We describe a 30-year-old man with uremia who underwent subtotal parathyroidectomy because of secondary hyperparathyroidism with very high serum parathyroid hormone (PTH) level (1940.4 pg/mL). Two weeks later, he complained of a sharp pain in both knees without trauma when he walked downstairs with his left knee forward and right knee behind. Spontaneous simultaneous ruptures of the right patellar tendon and the left quadriceps tendon were diagnosed and surgically repaired. The mechanism of spontaneous tendon rupture in uremic patients with secondary hyperparathyroidism seems to be related to high PTH level which results in osteolytic bone resorption at the tendon insertion site. Early surgical repair, control of secondary hyperparathyroidism, early use of vitamin D analogs, and total parathyroidectomy with or without autotransplantation of part of the parathyroid gland, can treat and prevent tendon rupture or re-rupture with satisfactory results.

In vivo anatomy of the Neer and Hawkins sign positions for shoulder impingement

The Neer and Hawkins impingement signs are commonly used to diagnose subacromial pathology, but the anatomy of these maneuvers has not been well elucidated in vivo. This 3-dimensional open magnetic resonance imaging study characterized shoulder anatomy and rotator cuff impingement in 8 normal volunteers placed in the Neer and Hawkins positions. Subacromial and intraarticular contact of the rotator cuff was graded, and minimum distances were computed between the tendon insertion sites and the glenoid, acromion, and coracoid. Both the Neer and Hawkins maneuvers significantly decreased the distance from the supraspinatus insertion to the acromion and posterior glenoid and from the subscapularis insertion to the anterior glenoid. However, the Hawkins position resulted in significantly greater subacromial space narrowing and subacromial rotator cuff contact than the Neer position. In the Hawkins position, subacromial contact of the supraspinatus and infraspinatus was observed in 7 of 8 and 5 of 8 subjects, respectively. In contrast, rotator cuff contact with the acromion did not occur in any subject in the Neer position. Intraarticular contact of the supraspinatus with the posterosuperior glenoid was observed in all subjects in both positions. Subscapularis contact with the anterior glenoid was also seen in 7 of 8 subjects in the Neer position and in all subjects in the Hawkins position. This extensive intraarticular contact suggests that internal impingement may play a role in the Neer and Hawkins signs.

Ultrasound detection of entheseal insertions in the foot of patients with spondyloarthropathy

The aim of the study was to evaluate entheseal involvement in the foot of patients with spondyloarthropathy (SpA) by ultrasonographic (US) examination and compare the results with clinical and radiological findings. Forty-four patients (27 men, 17 women) with a diagnosis of SpA were recruited. Patient evaluation included physical examination (swelling and pain), Bath Ankylosing Spondylitis Radiological Index, Bath Ankylosing Spondylitis Disease Activity, Bath Ankylosing Spondylitis Metrological Index, and laboratory parameters (erythrocyte sedimentation rate, C-reactive protein). Foot x-rays of the patients were assessed and scored according to SpA Tarsal Radiographic Index (SpA-TRI). A high-resolution US was used to examine the tendon and ligament insertion sites in the foot, and the findings were scored according to Glasgow Ultrasound Enthesitis Scoring System (GUESS). The mean age and disease duration of the patients were 39.9+/-12.5 and 9+/-8.2 years, respectively. US revealed pathological findings in 25 of 44 (56.8%) patients, most of whom exhibited no clinical signs of foot involvement. Pain and swelling at entheseal insertions were detected in only 16 (37%) patients. The mean GUESS score and SpA-TRI score were 2.2+/-2.5 and 3.3+/-3.7, respectively. There was a correlation between the scores of GUESS and SpA-TRI, particularly at the Achilles and plantar fascia insertion sites. The mean score of SpA-TRI was higher in patients with enthesopathy, detected by US, than in patients without enthesopathy (4.6+/-4.4 vs 1.8+/-2.1). There was no significant correlation between the mean GUESS score and clinical and laboratory variables. In conclusion, involvement of tendon and entheses is not rare, and US is a valuable diagnostic method in detecting subclinical enthesopathic changes. The GUESS and SpA-TRI are suggested in quantifying US and radiological changes in the foot of patients with SpA.