Development of the glenohumeral joint after subscapular release and open relocation in children with brachial plexus birth palsy: long-term results in 61 patients.

BACKGROUND: We present the long-term results of remodeling of the glenohumeral joint after open subscapularis elongation and relocation of the humeral head in patients with an internal rotation contracture and joint incongruity due to brachial plexus birth palsy. METHODS: In this before-and-after study, 61 patients who underwent open subscapularis elongation and reduction of the glenohumeral joint were evaluated with respect to joint remodeling, with a mean follow-up period of 10.2 years (range, 7-16 years). The mean age at operation was 3.2 years (range, 8 months to 15 years). Measurements of the percentage of the humeral head anterior to the midscapular line (PHHA), glenoid version, and diameter of the humeral head were recorded using magnetic resonance imaging, comparing the affected joints preoperatively vs. postoperatively (n = 31) and comparing the operated vs. unaffected sides postoperatively (n = 61). RESULTS: The mean increase in PHHA was 27.6 percentage points (95% confidence interval, 22.4-32.7 percentage points; P < .01), from 13.2% to 40.8%. The glenoid retroversion changed by 14.8° (95% confidence interval, 11.1°-18.4°; P < .01), from 25.4° to 10.6°, approaching a normal value. All patients, even those older than 5 years, showed a clear benefit from surgery. CONCLUSIONS: Our study confirms that open subscapularis lengthening with joint repositioning, up to the age of 5 years, gives consistent remodeling of incongruent shoulders with surprisingly small differences between the operated and unaffected shoulders at long-term follow-up. The findings indicate that open reduction is useful also in adolescents and challenges the notion that older children should be treated with derotational humeral osteotomy.

Use of a Novel, Reinforced, Low Immunogenic, Porcine Small Intestine Submucosa Patch to Repair a Supraspinatus Tendon Defect in a Rabbit Model.

BACKGROUND: Repairs of large to massive rotator cuff tears have a high failure rate. We investigated the efficacy of a novel, reinforced, low immunogenic, porcine small intestine submucosa (SIS) patch to repair a supraspinatus tendon defect in a rabbit model. We hypothesized that the histological and biomechanical results of SIS patch repair would be comparable with those of autologous fascia lata (FL) repair. METHODS: The study mainly comprised two parts. First, the characteristics of the SIS patch were evaluated, including its micromorphology, mechanical properties, and immunogenic properties. Second, a supraspinatus tendon defect model was created in 36 rabbits (72 shoulders). The bilateral shoulders were randomly chosen to undergo repair using either a SIS patch (SIS group) or autologous FL (FL group). At 4, 8, and 12 weeks, histological analysis was performed using four shoulders from each group, and biomechanical tests were performed using eight shoulders from each group. RESULTS: The SIS patch was a three-dimensional construct mainly composed of collagen fibers. The mean single and double suture retention loads of the SIS patch were 48.6 ± 5.8 N and 117.9 ± 2.7 N, respectively. The DNA content in the SIS patch was 53.9 ± 10.9 ng/mg dry weight. Both the histological score and ultimate load to failure increased in a time-dependent manner in both groups, with no significant differences between the SIS and FL groups at 12 weeks. CONCLUSION: Repair of a large supraspinatus tendon defect using a reinforced, low immunogenic, SIS patch achieves similar effects as autologous FL in a rabbit model. This novel patch might be useful to be employed as a structural tissue replacement in medical activities.

Computational analysis of glenohumeral joint growth and morphology following a brachial plexus birth injury.

Children affected with brachial plexus birth injury (BPBI) undergo muscle paralysis. About 33% of affected children experience permanent osseous deformities of the glenohumeral joint. Recent evidence suggests that some cases experience restricted muscle longitudinal growth in addition to paralysis and reduced range of motion at the shoulder and elbow. It is unknown whether altered loading due to paralysis, muscle growth restriction and contracture, or static loading due to disuse is the primary driver of joint deformity after BPBI. This study uses a computational framework integrating finite element analysis and musculoskeletal modeling to examine the mechanical factors contributing to changes in bone growth and morphometry following BPBI. Simulations of 8 weeks of glenohumeral growth in a rat model of BPBI predicted that static loading of the joint is primarily responsible for joint deformation consistent with experimental measures of bone morphology, whereas dynamic loads resulted in normal bone growth. Under dynamic loading, glenoid version angle (GVA), glenoid inclination angle (GIA), and glenoid radius of curvature (GRC) (-1.3°, 38.2°, 2.5 mm respectively) were similar to the baseline values (-1.8°, -38°, 2.1 mm respectively). In the static case with unrestricted muscle growth, these measures increased in magnitude (5.2°, -48°, 3.5 mm respectively). More severe joint deformations were observed in GIA and GRC when muscle growth was restricted (GVA: 3.6°, GIA: -55°, GRC: 4.0 mm). Predicted morphology was consistent with literature reports of in vivo glenoid morphology following postganglionic BPBI. This growth model provides a framework for understanding the most influential mechanical factors driving glenohumeral deformity following BPBI.

Morphometric parameters of the glenoid labrum

The glenoid labrum has an important role in glenohumeral joint stability, yet its morphometric parameters are seldom reported. This study aimed to (I) investigate the thickness and height of the glenoid labrum, and (ii) determine whether there is any significant difference between side and sex. A total of 140 shoulders (30 male and 40 female cadavers, average age of 81.5 years) were obtained for this study. All muscles and blood vessels surrounding the glenohumeral joint, as well as the fibrous capsule, were inspected and then removed to expose the glenoid fossa with the labrum attached. Measurement of labral height and thickness at the superior (12 o'clock), anterior (3 o'clock), inferior (6 o'clock) and posterior (9 o'clock) regions were taken. Gender, side and thickness and height measurements of the glenoid labrum were double- entered into the Statistical Package for Social Sciences. ANOVA and MANOVA tests were conducted to determine statistical significance, which was set at P<0.05. Significant differences in thickness (at the superior, inferior and posterior aspects) and height (at the superior and inferior aspects) of the glenoid labrum were observed between males and females, being thicker and taller in males in all regions. Based on the side of the limb, no differences in labral thickness and height were observed with respect to side. The current observations confirm that the glenoid labrum height and thickness are associated with sex, but not with side

No disponible

Pediatric and adolescent anterior shoulder instability: clinical management of first-time dislocators.

PURPOSE OF REVIEW: The purpose of this review is to discuss the epidemiology, pathoanatomy, diagnosis, and clinical management of pediatric and adolescent patients following a first-time shoulder dislocation. RECENT FINDINGS: Shoulder instability is becoming increasingly common as pediatric and adolescent patients engage in earlier organized sports competition. Recommended treatment following a first-time glenohumeral dislocation event in adolescents depends on several factors, but surgical stabilization is becoming more frequently performed. Surgical indications include bony Bankart lesion, ALPSA lesion, bipolar injury (e.g. Hill-Sachs humeral head depression fracture) or off-season injury in an overhead or throwing athlete. Complications following surgical treatment are rare but most commonly are associated with recurrent instability. Young children (eg. open proximal humerus growth plate), individuals averse to surgery, or in-season athletes who accept the risk of redislocation may complete an accelerated rehabilitation program for expedited return to play in the absence of the structural abnormalities listed above. SUMMARY: Following a first-time dislocation event in pediatric and adolescent patients, a detailed discussion of the risks and benefits of nonoperative versus operative management is critical to match the recommended treatment with the patient's injury pattern, risk factors, and activity goals.

Recovery potential after postnatal shoulder paralysis. An animal model of neonatal brachial plexus palsy.

BACKGROUND: Injury to the brachial plexus during birth results in paralysis of the upper extremity in as many as one in 250 births and can lead to substantial functional deficits in the shoulder. The goal of this study was to characterize the development of bone and joint deformities in paralyzed neonatal shoulders and to assess the improvement of these deformities after muscle function recovery with use of an animal model. METHODS: Intramuscular injections of botulinum toxin were used to paralyze the supraspinatus, infraspinatus, and posterior deltoid of the left shoulders of mice at birth. Seventy mice were divided into three groups: Botox, recovery, and normal. The twenty-five mice in the Botox group received botulinum toxin injections until they were killed. The twenty mice in the recovery group received botulinum toxin injections for different durations and then were allowed injection-free recovery periods until they were killed. The twenty-five mice in the normal group received saline solution injections until they were killed. Radiographs were used to measure shoulder and elbow contractures. Microcomputed tomography was used to examine anatomical parameters of the supraspinatus muscle, humerus, and scapula. RESULTS: The Botox group showed bone and joint deformities including delayed mineralization and flattening of the humeral head, hypoplasia, and introversion (i.e., anteversion) of the humerus, contractures of the shoulder and elbow, hypoplasia of shoulder muscles, hypoplasia of the scapula, and hypoplasia and retroversion of the glenoid. In the recovery group, a significant trend toward normal properties was observed with longer recovery periods (p<0.05). However, only soft-tissue contractures of the shoulder and elbow were resolved completely with the longest recovery period. CONCLUSIONS: This mouse model successfully simulates human neonatal brachial plexus palsy, reproducing most of the bone and joint deformities found in the human condition. The deformities started to develop early in the postnatal period in the paralyzed shoulders and progressed with longer durations of paralysis. Early restoration of muscle function completely resolved the soft-tissue contractures of the shoulder and elbow. However, osseous deformities of the humerus and scapula were never resolved completely. These findings demonstrate the time-dependence of reversibility of musculoskeletal deformities in developing shoulders with neurological deficits.

Evaluation of shoulder balance in the normal adolescent population and its correlation with radiological parameters.

A descriptive clinical study in healthy adolescents was done to evaluate the clinical shoulder balance and analyze the correlation between clinical and radiological parameters which are currently used to evaluate shoulder balance. In addition to trunk shift and rib hump, shoulder balance is one of the criteria that are used to evaluate the outcomes in spinal deformity surgery. Several methods have been proposed to evaluate the shoulder balance in scoliotic patients; however, there is no uniformity to these methods in the current literature. Patients who applied to pediatric clinic without musculoskeletal pathology formed the patient population. Volunteers were asked to fill out a questionnaire assessing shoulder balance perception and had their clinical photograph taken simultaneously with a P-A chest X-ray. The clinical shoulder balance was evaluated through analysis of the clinical photograph. The X-rays were used to evaluate the radiological shoulder balance. The evaluated parameters included coracoid height difference (CHD), clavicular angle (CA), the clavicle-rib cage intersection difference (CRID), clavicular tilt angle difference (CTAD), and T1-tilt. The study group was composed of 48 male and 43 female patients with an average age of 13.6 +/- 2.1 (10-18) years. In the questionnaire, all patients stated that their shoulders were level. The digital photographs revealed that only 17(18.7%) adolescents had absolutely level shoulders. The average height difference between shoulders was 7.5 +/- 5.8 mm. The average CHD was 6.9 +/- 5.8 mm, average CA was 2.2 +/- 1.7 degrees , average CRID was 4.8 +/- 3.6 mm, average CTAD was 4 +/- 3.2 degrees , and average T1-tilt was 1.3 +/- 1.4 degrees . CHD, CA, and CRID demonstrated high correlation with clinical pictures, whereas CTAD demonstrated moderate and T1-tilt demonstrated only mild correlation. The radiological parameters used to evaluate the shoulder balance correlate with the clinical appearance. Contrary to popular belief, shoulder balance in healthy adolescents often does not exist.

Development of the supraspinatus tendon-to-bone insertion: localized expression of extracellular matrix and growth factor genes.

The adult healing response of the rotator cuff tendon-to-bone insertion site differs from the ordered process of insertion site development. Healing is characterized by disorganized scar and a lack of fibrocartilage formation, in contrast to the well organized fibrocartilaginous transition which forms during the normal development of the tendon-to-bone insertion. The purpose of this study was to localize the expression of a number of extracellular matrix and growth factor genes during insertion site development in order to guide future strategies for augmenting adult rotator cuff healing. The rotator cuff was morphologically distinct at 13.5 dpc (days postconception). Neo-tendon was evident as a condensation of cells adjacent to bone. The interface between tendon and bone did not form into a mature fibrocartilaginous insertion until 21-days postnatally, based upon the appearance of four distinct zones with a mineralized humeral head. Fibroblasts of the supraspinatus tendon expressed type I collagen at all timepoints. Type II collagen was first expressed by chondrocytes in the fibrocartilage and mineralized fibrocartilage at 7 days and persisted in the mineralized fibrocartilage at 56 days. Type X collagen was first expressed by the chondrocytes in the mineralized fibrocartilage at 14 days and persisted in the mineralized fibrocartilage at 56 days. A shift from TGF-beta3 to TGF-beta1 expression occurred at 15.5 dpc.

Growth of the pectoral girdle of the Leopard frog, Rana pipiens (Anura: Ranidae).

This article describes the growth of the anuran pectoral girdle of Rana pipiens and compares skeletal development of the shoulder to that of long bones. The pectoral girdle chondrifies as two halves, each adjacent to a developing humerus. In each, the scapula and coracoid form as single foci of condensed chondrocytes that fuse, creating a cartilaginous glenoid bridge articulating with the humerus. Based on histological sections, both the dermal clavicle and cleithrum begin to ossify at approximately the same time as the periosteum forms around the endochondral bones. The dermal and endochondral bones of the girdle form immobile joints with neighboring girdle elements; however, the cellular organization and growth pattern of the scapula and coracoid closely resemble those of a long bone. Similar to a long bone epiphysis, distal margins of both endochondral elements have zones of hyaline, stratified, and hypertrophic cartilages. As a result, fused elements of the girdle can grow without altering the glenoid articulation with the humerus. Comparisons of anuran long bone and pectoral girdle growth suggest that different bones can have similar histology and development regardless of adult morphology.

Effect of tendon transfers and extra-articular soft-tissue balancing on glenohumeral development in brachial plexus birth palsy.

BACKGROUND: Persistent muscle imbalance and soft-tissue contractures can lead to progressive glenohumeral joint deformity in patients with brachial plexus birth palsy. The objective of this investigation was to determine the effects of correction of external rotation weakness and internal rotation contractures with tendon transfers and extra-articular soft-tissue releases on glenohumeral development in patients with brachial plexus birth palsy. METHODS: Twenty-five patients with brachial plexus birth palsy who underwent latissimus dorsi and teres major tendon transfers to the rotator cuff-with or without concomitant musculotendinous lengthenings-were evaluated clinically and radiographically before the operation and at a minimum of two years (average, forty-three months) postoperatively. Shoulder function was prospectively assessed with use of the modified Mallet classification system, in which aggregate shoulder function is assigned a score of 5 to 25 points. Glenoid version and humeral head subluxation were quantified with magnetic resonance imaging or computed tomography, and glenohumeral deformity was graded. RESULTS: Clinically, all patients demonstrated improved global shoulder function, with the mean aggregate Mallet score improving from 13 points preoperatively to 18 points postoperatively (p < 0.01). As seen radiographically, the mean glenoid retroversion improved from 22 degrees preoperatively to 16.5 degrees postoperatively (p = 0.012). The mean posterior humeral head subluxation improved from 30% to 37% (p = 0.03). No patient had progressive worsening of the glenohumeral deformity. CONCLUSIONS: Latissimus dorsi and teres major tendon transfers to the rotator cuff, combined with appropriate extraarticular musculotendinous lengthenings, significantly improved global shoulder function but led to only modest improvements in glenoid retroversion and humeral head subluxation. No profound glenohumeral remodeling occurs after these extra-articular rebalancing procedures, even when they are performed in patients of a young age. While the long-term clinical and radiographically apparent effects at skeletal maturity are uncertain, soft-tissue rebalancing procedures alone were found to have halted the progression of, but not to have markedly decreased, glenohumeral dysplasia at the time of a two to five-year follow-up.

[Ultrasound anatomy of the shoulder joint during the growth period]. / Sonoanatomie des Schultergelenks im Wachstumsalter.

AIM OF STUDY: It is the aim of this investigation to describe the normal ultrasonographical appearance of the glenohumeral joint in childhood. METHODS: Ultrasound investigation was performed in 20 healthy children aged between 6 weeks and 19 years (median: 6 years) using 12 MHz linear probes. A dynamic examination of both shoulders was carried out. Probe positions according to standard planes were used, and attention was paid to visualise the growth regions. RESULTS: Ultrasound images of the periarticular soft tissue in children do not differ markedly from those in adults. However, there are basic structural differences of the epiphyseal and apophyseal regions. In the newborn period the proximal humeral epiphysis mainly consists of cartilage and changes to the adult shape after the appearance of three secondary ossification centers and growth plates. Interestingly, the chondral buds of the acromion or coracoid process offer additional imaging facilities for ultrasound examination in children. CONCLUSIONS: Ultrasound examination of the glenohumeral joint in children offers a more precise evaluation when compared to adults, due to the presence of additional ultrasonographical "windows" and depiction of parts of the humeral epiphysis. This imaging technique is well tolerated by children.

The development of humeral head retroversion.

Humeral head retroversion is important in a variety of clinical situations, but it is not known when retroversion actually develops to adult values. In utero and at birth, the humeral head is known to be in marked retroversion. It derotates sometime thereafter to assume the more standard value with which orthopedic surgeons are familiar. By studying a unique collection of children's bones (180 humeri), I have been able to determine that the greater part of this process takes place, on average, by the age of 8 years (SD +/- 2.12 years); from then on, however, the development continues more slowly until the final adult dimensions are reached, as heralded by the appearance of the radial groove at approximately 16 years of age. This process, along with its timing, appears to be similar, but opposite in direction to, the derotation process that is known to take place in the hip. It has not previously been documented in the shoulder.

Abnormalities of the adult shoulder due to sickle cell osteonecrosis during childhood.

PATIENTS AND METHODS: A retrospective study of 110 adults with sickle cell anemia (SS genotype) was conducted to determine the frequency of complications of sickle cell osteonecrosis of the shoulder in childhood. The glenohumeral joint was evaluated on plain anteroposterior and lateral radiographs of the shoulder. RESULTS: Mean time since osteonecrosis of the shoulder was 24 years. Radiographic abnormalities were seen in 106 of the 220 shoulders (48.2%). Both shoulders were affected in 86% of cases and at least one hip in 96%. Radiographic abnormalities included isolated caput magna, caput plana, a short humeral neck and ascension of the tuberosities. Twelve shoulders exhibited glenoid fossa abnormalities, which consisted in complete or partial hypoplasia. Evidence of glenohumeral osteoarthritis was seen in 11 shoulders. DISCUSSION: The shoulder abnormalities seen in our patients were probably due to growth disturbances in the proximal humerus secondary to osteonecrosis of the humeral head during childhood. They were common but less likely to produce functional impairment than osteonecrosis-related lesions of the hip. However, some patients had premature osteoarthritis and geometric shoulder abnormalities responsible for functional loss in adulthood.

Magnetic resonance imaging of the shoulder in children with brachial pLexus birth palsy.

Five patients suffering from Erb-Duchenne brachial plexus birth palsy were prospectively studied with MRI. A group of 11 healthy children was used as a control to understand the MRI anatomy of the normal growing glenohumeral joint. A hypoplastic and flattened posterior part of the glenoid fossa and a blunt posterior labrum were found in all patients. Four patients had a blunt anterior labrum and a flattened humeral head. Three patients presented with a posterior subluxation of the humeral head. These results suggest that MRI provides a non-ionising and non-invasive method of demonstrating the early abnormalities of the shoulder associated with obstetrical brachial plexus paralysis, which may prompt orthopaedic correction.

The shoulder and elbow in Apert's syndrome.

Nine children with Apert's syndrome were studied and found to have progressive bony dysplasia in the shoulder and elbow. The children showed loss of joint motion and radiographic abnormalities including subluxation and flattening of the humeral head with irregularities of the glenoid. The elbow showed flattening and subluxation of the radial head in radiographs and a positive click on physical examination. The limitation of motion and the presence of bony defects were progressive, suggesting that Apert's syndrome is a progressive generalized dysplasia.

Diarthroses in the mouse: from different cellular structure to similar joint appearance.

The structure and function of two major joints, the humeroscapular and the squamoso-mandibular joints in mice, are compared. The specific roles that these two joints fulfill during early postnatal period are reflected in a different cellular organization observed in them. Following maturation, when similar functional needs are stressed upon these two joints, similar homologous structures are detected in both of them. A possible conceptual explanation for these observations and their relatedness to the human equivalent joints are discussed.

[Chronology of the postnatal ossification of the shoulder and elbow joints in the Siamese cat (Felis catus L.)]. / Cronología de osificación postnatal de las articulaciones del hombro y codo en el gato siamés (Felis catus L.).

A study was done by radiological techniques to show the chronology of ossification of the shoulder and cubit joints in the Siam cat, from birth up to the 25th week of postnatal development. For this experiment we used 40 little cats (19 males and 21 females) belonging to 11 litters subjected to different controls: pattern race, healthy, feeding, growing up and radioactivity. The time of the appearance and the evolution of the ossification centers is determined as well as the phenomenon of fusion during this time. The postnatal ossification from both joints of the Siam cat is compared with that of the common cat.

[Age-related changes in large joints and long tubular bones of the upper extremity in children (echographic data)]. / Vozrastnye izmeneniia krupnykh sustavov i dlinnykh trubchatykh kostei verkhnikh konechnostei u detei (po dannym ékhografii).

Two hundred and ten children at the age of 17 days up to 15 years have been examined. Echocameras, working in the grey scale regime have been used. At examination of the arm, forearm, brachial, elbow and radiocarpal joints in the children the most informative are longitudinal echographic approaches. At examination of the brachial bone head in the children older than 10 years only the anterior longitudinal approach is informative. To perform the echographic investigation of various elements of the locomotor apparatus of the upper extremities in children older than 9-10 years is difficult. The echographic reveal of additional nuclei of ossification and synostosis stages of the long tubular bones of the upper extremities in children often coincide in time with roentgenological data.

Aging in the musculoskeletal system of rhesus monkeys: I. Passive joint excursion.

In order to describe ontogenetic change in the musculoskeletal system of rhesus monkeys, 126 Macaca mulatta from Cayo Santiago, ranging in age from 7 months to 21 years, were examined under anesthesia. Passive joint excursions were measured at the wrist, elbow, shoulder, hip, and knee. Mean ranges of excursion at these joints differed significantly between age groups and by sex. The potential for most movements appeared to decrease approximately 25 degrees over the first two decades of the macaque life span, and males generally showed less potential for movement than females in all age groups. These results are similar to those obtained for humans and are consistent with patterns of positional behavior, trauma, and osteoarthritis observed in this rhesus monkey population. Thus, to fully describe the locomotor strategy of rhesus monkeys, age- and sex-related variation in locomotor anatomy and functional capacity must be considered.