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PubMed2006

[Three-dimensional geometry of the proximal humerus and rotator cuff attachment and its utilization in shoulder arthroplasty].

PURPOSE OF THE STUDY: The aim of the study was to provide a method of measurement and data collection, based on morphologic analysis of the proximal humerus, that would facilitate precise placement of the humeral stem and would be easy to apply in clinical medicine in patients requiring shoulder arthroplasty. MATERIAL: Three groups of materials were used. Materials for the first and second groups were provided by the Department of Anatomy, First Faculty of Medicine, Charles University. The first group included 10 specimens (five left and five right humeral bones) obtained at routine anatomical dissection. The second group contained 110 so-called dry preparations from the collections of the Department of Anatomy and the third group comprised nuclear magnetic resonance (NMR) scans of 20 patients. To show spatial relationships between the proximal and the distal humerus, another coil was applied to the epicondylar region in addition to the one placed over the proximal humerus. METHODS: The first group material was used to study proximal humerus morphology and to determine reference points for the other two groups. The points were constructed to make seven planes perpendicular to the axis of the proximal humeral metaphysis. Based on the reference points, parameters of the proximal humerus were assessed in the defined planes also in the other two groups. We measured angles between the reference points and the transepicondylar line or the humeral head axis. The vertex of each angle was always placed in the point of intersection of the metaphyseal axis and the given transverse plane. Reference points of the greater tubercle were marked on the medial margin continuous with the intertubercular groove, on the lateral margin of the lesser tubercle and in the "deepest" place of the intertubercular groove. We also measured humeral head retroversion and the position of maximal bony mass of both the greater and the lesser tubercle (this parameter can be used with advantage for optimal insertion of screws in proximal humerus reconstruction). RESULTS: The angle between the medial margin of the greater tubercle and the humeral head axis was on average 164.8 degrees on the left side and 163.2 degrees on the right side; the angle between the great tubercle margin and the transepicondylar line was 137.0 degrees on the left humerus and 137.7 degrees on the right humerus. The lateral margin of the lesser tubercle and the humeral head axis formed on average an angle of 124.4 degrees and of 122.6 degrees on the right and the left side, respectively. The intertubercular groove/ humeral head axis relationship was 143.4 degrees and 144.8 degrees for the left and the right humerus, respectively, and the intertubercular groove/transepicondylar line angle was 115.6 degrees for the left and 119.5 degrees for the right humerus. The humeral head axis and the transepicondylar line made an angle of 27.8 degrees for the left and 25.3 degrees for the right humerus. These values corresponded to the angle of the humeral head retroversion. The reference point of maximal bony mass of the greater tubercle and the humeral head axis made an angle of 181.1 degrees and of 180.2 degrees for the left and the right humerus, respectively; between this point and the lesser tubercle was an angle of 120.2 degrees for the left and 126.9 degrees for the right humerus. DISCUSSION: One of the most important parameters in restoring shoulder function by alloplasty is humeral head retroversion. If this is not correct, ventral or, less frequently, dorsal instability of the shoulder may result. The correct setting of retroversion is guided by the transepicondylar line or several specific landmarks on the greater and the lesser tubercle of the humerus. Another important factor is the correct reconstruction of anatomic position of the greater and the lesser tubercle in relation to the insertion of rotator cuff muscles into the humeral head. Relationships of diaphyseal, metaphyseal and humeral head axes have been reported in the relevant literature dealing with proximal femoral morphology. None of the reports, however, has dealt with tubercular angles and position of the maximal body mass, which is a decisive factor for insertion of screws fixing the prosthetic stem. CONCLUSIONS: The values provided here can be used for a more precise construction of implants for shoulder replacement. The method of three-dimensional presentation of the proximal humerus may aid in a more exact implantation procedure during shoulder arthroplasty. An optimal position of the implant can also be based on parameters obtained from the healthy contralateral shoulder joint.

Anthropometry↗

PubMed2003

Prenatal assessment of normal fetal humerus volume by three-dimensional ultrasound.

Because fetal humerus dysplasia is associated with a variety of congenital syndromes, prenatal assessment of the fetal humerus growth is very important. The fetal humerus volume is one of the indexes in evaluating the humerus growth, but it has never been studied by 3-D ultrasound (US) in utero. To establish a normal reference chart of the fetal humerus volume for clinical use, we undertook a prospective and cross-sectional study using 3-D US to assess the fetal humerus volume in normal pregnancy. A total of 216 singleton fetuses that ranged between 20 and 40 weeks of gestation and fit the criteria of normal pregnancies were included in this study. Our results showed that the fetal humerus volume is highly correlated with the gestational age (GA). Using GA as the independent variable and the humerus volume as the dependent variable, the best-fit regression equation was humerus volume (mL) = 0.0044GA(2) - 0.0841GA + 0.6874 (r = 0.97, n = 216, p < 0.0001). For clinical use, a chart of normal growth centiles of the fetal humerus volume was then established based on this equation. In addition, the common indexes of fetal biometry, such as biparietal diameter, occipitofrontal diameter, head circumference, abdominal circumference, femur length and estimated fetal weight, were all highly correlated with the humerus volume (all p < 0.0001). In conclusion, our data of the fetal humerus volume assessed by 3-D US can serve as a useful reference in evaluating the fetal humerus growth during normal gestation.

Adult↗

PubMed2002

Value of humerus length shortening for prenatal detection of Down syndrome in a Thai population.

OBJECTIVE: To assess the value of humerus length shortening for prenatal detection of Down syndrome in a Thai population. METHODS: A prospective study was performed on 3053 women undergoing second-trimester amniocentesis, between 16 and 24 weeks gestation, for the indications of advanced maternal age and a past history of chromosomal abnormality. Biparietal diameter (BPD) and humerus length measurements were obtained before the procedures. Regression equations relating BPD to humerus length were used to calculate observed humerus length/expected humerus length ratio in chromosomally normal and Down syndrome fetuses. Sensitivity, specificity, false-positive rate and likelihood ratio of a positive test result at various observed humerus length/expected humerus length ratios for detection of Down syndrome were calculated. A receiver-operator characteristic curve was used to determine the threshold screening ratio. RESULTS: There were 3003 chromosomally normal pregnancies and 24 fetuses with Down syndrome. The relationship between humerus length and BPD was: expected humerus length = 0.7403BPD - 5.1057, R2= 0.77, P < 0.001. Humerus length in Down syndrome fetuses was significantly shorter than in normal fetuses (P < 0.001). A ratio of 0.91 for observed humerus length/expected humerus length yielded a sensitivity of 41.7%, specificity of 88.3%, a false-positive rate of 11.7% and likelihood ratio of a positive test result of 3.63 (95% confidence interval 2.24-5.88) for detection of Down syndrome. CONCLUSIONS: Humerus length shortening in the second trimester appears to be a useful adjunctive screening parameter for fetal Down syndrome in a Thai population.

Amniocentesis↗

PubMed1993

Humerus and femur length shortening in the detection of Down's syndrome.

OBJECTIVE: Our purpose was to determine the utility of screening for humerus and femur length shortening in prenatal detection of Down's syndrome (trisomy 21). STUDY DESIGN: On the basis of the biparietal diameter, predicted humerus and femur lengths were derived from a sample control group of 350 karyotypically normal fetuses. The regression formulas were prospectively applied to 45 consecutive fetuses with Down's syndrome and 942 fetuses with normal karyotypes. Ratios of measured humerus length/predicted humerus length and measured femur length/predicted femur length were calculated for each fetus. RESULTS: Eleven of 45 (24.4%) fetuses with Down's syndrome had short humerus (measured humerus length/predicted humerus length ratio of < or = 0.89), and 11 (24.4%) had short femur (measured femur length/predicted femur length ratio of < or = 0.91. In comparison, among 942 karyotypically normal fetuses only 43 (4.5%) showed short humerus and 44 (4.7%) showed short femur (p < 0.05). Fetuses with both short humerus and short femur carried an 11-fold greater risk of Down's syndrome (risk ratio = 11.1; 95% confidence interval = 5.0 to 25.0). CONCLUSION: Prenatal ultrasonographic detection of short humerus to short femur, or both significantly increase the risk of Down's syndrome; this information may be useful in screening programs.

Bone Lengthening↗

PubMed2005

Long-term denervation of the humerus in turkeys as an experimental model for osteopenia.

The aim of this study was to evaluate the influence of long-term denervation on volumetric bone mineral density, and geometrical and mechanical properties of the humerus in turkeys. The experiment was conducted from d 22 after hatching until wk 17 of life. All experimental birds (male turkeys) were randomly divided into 2 weight-matched groups. The first group of turkeys served as the control group and underwent a sham operation on the right wing, and the second group was subjected to surgical denervation of the right humerus. The denervation was performed by neurectomy of the radialis and the mediano-ulnaris nerves in the region of the proximal epiphysis of the humerus. All the left wings within both groups were surgically untouched. The left humerus served as the control bone to the right humerus in both investigated groups. Effect of denervation of humerus was determined in terms of geometrical and mechanical properties and quantitative computed tomography. The denervation of the humerus in turkeys significantly decreased volumetric bone mineral density, and geometrical and mechanical properties of this bone, when compared with the results obtained in humerus from the sham-operated or surgically untouched wings. However, no significant differences between right and left humerus were observed when analyzing all of the investigated parameters in the sham-operated group of turkeys. It is concluded that long-term denervation of humerus in turkeys induces osteopenia and may serve as a new experimental model for investigating factors that affect skeletal homeostasis in poultry and other vertebrates.

Animals↗

PubMed2006

Vascular implications of minimally invasive plating of proximal humerus fractures.

OBJECTIVES: Open reduction and internal fixation of proximal humerus fractures through the anterolateral acromial approach, which uses the anterior deltoid raphe and axillary nerve protection, has recently been advocated as a minimally invasive technique. Several recent reports have indicated variable and unpredictable vascular injuries to the humeral-head blood supply after a proximal humerus fracture, and thus a direct approach that minimizes further vascular compromise may be preferable. The purpose of this study was to define the relationship of this surgical interval to the lateral plating zone of the proximal humerus and to the penetrating vascular supply of the humeral head. DESIGN: Cadaveric vascular injection study. SETTING: Cadaveric dissection laboratory. PATIENTS: Six cadaveric specimens. INTERVENTION: The anterolateral acromial approach was performed on six cadaveric upper-extremity specimens. A locking proximal humerus plate was applied to the lateral proximal humerus, and the axillary artery was cannulated proximal to the circumflex humeral arteries. Dyed latex polymer was injected and allowed to harden, and dissection was performed to visualize the vasculature of the proximal humerus. Plates were then removed and the specimens were further inspected to examine the blood supply. MAIN OUTCOME MEASUREMENTS: The relationship of the anterolateral acromial approach to the lateral plating zone of the proximal humerus and the vascular supply of the humeral head. RESULTS: In all specimens, the filling of the anterior and posterior vessels that supplied the humeral head were undisturbed after use of the anterolateral acromial approach and locked plating. The blood vessels to the head-penetrating vascular branches were not in the surgical field. A bare spot on the lateral proximal humerus existed in the region of the greater tuberosity, which was 30 mm wide and between two penetrating humeral-head epiphyseal vessels. The nearest penetrating vessels were close to the plate, 4 mm anterior and 7 mm posterior. The anterior humeral circumflex vessel and its ascending branch, which provides critical blood supply to the humeral head, coursed directly in the region of the deltopectoral approach. CONCLUSIONS: Minimally invasive techniques have many potential benefits for fracture healing, but new surgical approaches often must be used to take full advantage of these newer methods. Splitting the anterior deltoid raphe from the acromion distally allowed direct access to the lateral plating zone of the proximal humerus. The bare spot in this region may be a safe area for plate application, if the plate is placed appropriately with thorough knowledge of the vascular anatomy. These findings may be of particular importance if the vascular supply to the humeral head has already been partially compromised by preceding trauma. This direct approach to the lateral bare spot on the proximal humerus may minimize iatrogenic vascular injury when treating these fractures.

Aged↗

PubMed2004

Femur and humerus length in trisomy 21 fetuses at 11-14 weeks of gestation.

OBJECTIVE: To determine the value of measuring fetal femur and humerus length at 11-14 weeks of gestation in screening for chromosomal defects. METHODS: Femur and humerus lengths were measured using transabdominal ultrasound in 1018 fetuses immediately before chorionic villus sampling for karyotyping at 11-14 weeks of gestation. In the group of chromosomally normal fetuses, regression analysis was used to determine the association between long bone length and crown-rump length (CRL). Femur and humerus lengths in fetuses with trisomy 21 were compared with those of normal fetuses. RESULTS: The median gestation was 12 (range, 11-14) weeks. The karyotype was normal in 920 fetuses and abnormal in 98, including 65 cases of trisomy 21. In the chromosomally normal group the fetal femur and humerus lengths increased significantly with CRL (femur length = - 6.330 + 0.215 x CRL in mm, r = 0.874, P < 0.0001; humerus length = - 6.240 + 0.220 x CRL in mm, r = 0.871, P < 0.0001). In the Bland-Altman plot the mean difference between paired measurements of femur length was 0.21 mm (95% limits of agreement - 0.52 to 0.48 mm) and of humerus length was 0.23 mm (95% limits of agreement - 0.57 to 0.55 mm). In the trisomy 21 fetuses the median femur and humerus lengths were significantly below the appropriate normal mean for CRL by 0.4 and 0.3 mm, respectively (P = 0.002), but they were below the respective 5th centile of the normal range in only six (9.2%) and three (4.6%) of the cases, respectively. CONCLUSION: At 11-14 weeks of gestation the femur and humerus lengths in trisomy 21 fetuses are significantly reduced but the degree of deviation from normal is too small for these measurements to be useful in screening for trisomy 21.

Adolescent↗

PubMed1988

Correlation of bone mineralization in the radius and humerus of well premature neonates over the first 4 months of life.

To determine how well mineralization correlates in the radius and humerus of neonates, we have measured with photon absorptiometry the bone mineral content (BMC) and bone width (BW) in the humerus and radius of well premature neonates and in the radius alone of well term neonates at birth, 8 and 16 weeks of age. These data allow (1) the correlation of bone mineralization in the humerus and radius at birth and over the first 4 months of life and (2) the correlation between bone mineralization in the radius or humerus at birth and that measured at 8 and 16 weeks in the same bone site. The BMC of the radius was significantly (P less than 0.02) correlated with the BMC of the humerus at birth, 8 and 16 weeks, but the BW of the radius was significantly correlated with the BW of the humerus only at 16 weeks. On the other hand, the BMC of the radius at birth in both term and premature neonates failed to correlate significantly (P = ns) with the BMC of the radius at 8 or 16 weeks. In the humerus, the BMC at birth was significantly (P less than 0.001) correlated with that measured at 8 but not at 16 weeks. These data indicate that the humerus and radius increase in mineral content at a similar rate over the first 4 months of life but that one cannot accurately predict from the BMC at birth what the bone mineral content will be at 8 and 16 weeks of age.

Aging↗

PubMed2006

Predicting fetal growth restriction by humerus volume: A three-dimensional ultrasound study.

Prenatal diagnosis of fetal growth restriction (FGR) is very important, as FGR may have increased risks with perinatal morbidity and mortality. Fetal humerus dysplasia is associated with a variety of congenital syndromes and FGR. For the assessment of the efficacy of fetal humerus volume in predicting FGR, we undertook a prospective cross-sectional study using quantitative three-dimensional (3D) ultrasound (US). In total, 42 fetuses with FGR and 258 fetuses without FGR were included for the humerus volume assessment in utero by 3D US. All the fetuses were singletons and were followed up to delivery to determine whether they were complicated with FGR or not. Our results revealed that fetal humerus volume assessed by 3D US can differentiate fetuses with FGR from fetuses without FGR well. The best predicting threshold for FGR is at the 10th percentile by humerus volume. Using the 10th percentile as the cutoff, the sensitivity of fetal humerus volume in predicting FGR was 97.6%, specificity 87.2%, positive predictive value 55.4%, negative predictive value 99.6% and accuracy 88.7%. In conclusion, fetal humerus volume assessed by quantitative 3D US can be used to predict FGR prenatally. We believe fetal humerus volume assessment by 3D US would be a useful test in detecting fetuses with FGR.

Epidemiologic Methods↗

PubMed2005

[Twenty nine shoulder reconstructions after resection of the proximal humerus for neoplasm with mean 7-year follow-up].

PURPOSE OF THE STUDY: Techniques available for shoulder reconstruction after resection of a tumor of the proximal humerus include scapulohumeral arthrodesis, humerus prosthesis with or without an allograft, inverted prostheses, and massive allografts. The purpose of this study was to review clinical and radiological outcomes in a series of 29 patients (20 men and 9 women) who underwent resection-reconstruction of the proximal humerus and to establish from these cases a decision making algorithm for therapeutic indications as a function of tumor invasion. MATERIAL AND METHODS: The tumors were 20 chondrosarcomas, five osteosarcomas, two Ewing sarcomas and one malignant hemangiopericytoma. In 17 patients epiphyso-metaphyseal or epiphyso-metaphyso-diaphyseal resection was performed with preservation of the abductor muscles (type S34A or S345A according to the Musculoskeletal Tumor Society classification). For 12 patients epiphyso-metaphyseal or epiphyso-metaphyso-diaphyseal resection was performed without preservation of the abductor muscles (type S34B or S345B). Reconstruction was achieved using a centromedullary cemented nail in one patient, scapulohumeral arthrodesis in three, a massive humerus prosthesis in 15, and composite humerus prosthesis in three and an inverted prosthesis in seven. The functional score of the Musculoskeletal Tumor Society (MSTS) and standard x-rays were used to assess outcome. RESULTS: Mean follow-up was 85 months (range 16-300). The mean MSTS score was 88% for inverted prostheses, 76% for composite prostheses, 72.6% for massive prostheses, 75% for scapulohumeral arthrodeses, 67% for massive prostheses, and 80% for cemented centromendullary nail. Five patients died from their malignant disease and one from another cause. Four patients are alive but with active disease after a mean follow-up of 108 months and 19 patients (65.5%) are alive and free of locoregional recurrence or metastasis after a mean 83.5 months. We had 28 complications. Glenohumeral instability was the most frequent (11 cases). DISCUSSION: Resection of the upper portion of the humerus should be performed to achieve cancerologically satisfactory tumor resection and enable shoulder resection, if possible, with preservation of a viable and functional abductor system. The functional outcome after such reconstruction depends on the type of bony resection, but also on the sacrifice of the rotator cuff and the deltoid muscle. In light of our experience and results in the literature, we advocate, despite the small number of cases for the different reconstructions, the following decision-making algorithm after resection of the proximal humerus without joint invasion: when the resection removes the rotator cuff and the deltoid (or the axillary nerve), there are two options: scapulohumeral arthrodesis or massive humerus prosthesis for patients who do not desire a complex therapy with a long postoperative period; when the resection preserves the rotator cuff and/or the deltoid muscle, reconstruction can be achieved with a composite (inverted or not) prosthesis with suture of the cuff tendons. We prefer the inverted composite prosthesis; if the deltoid muscle can be preserved but not the rotator cuff, the composite inverted prosthesis appears to be the most logical solution, but scapulohumeral arthrodesis can be proposed in selected cases.

Adolescent↗

PubMed2004

Humerus length evaluation in different ethnic groups.

OBJECTIVE: Femoral length has gained much attention for its use as a marker for Down syndrome, and racial variation has been evaluated. We hypothesized that no racial differences in humerus length will be shown from 14 to 22 weeks' gestation. METHODS: Our sonography database was queried from January 1, 1994, to September 30, 2001, for obstetric sonographic examinations of singleton fetuses. Cases with incomplete data, fetal anomalies, and cases without documented ethnicity were excluded. Only 1 examination per fetus was used. Individual parameters were evaluated from 14 to 22 weeks' gestation in white non-Hispanic, Hispanic, African American, Asian, and Eastern Indian women. Linear regression was used to model the relation of humerus length to menstrual age and to compare the humerus length for gestational age among ethnic groups. We compared the sensitivity for Down syndrome detection from a standard expected humerus length formula and ethnic-specific formulas. RESULTS: We identified 1164 fetuses: 380 white, 224 Hispanic, 432 African American, 116 Asian, and 12 Eastern Indian. Comparing with white fetuses, we found differences in humerus length among African American (P < .001) and Asian (P < .001) fetuses but not among Hispanic fetuses (P = .98). The sensitivity for Down syndrome detection from standard and ethnic-specific formulas was identical. CONCLUSIONS: In this cohort, small differences in humerus length exist among ethnic groups. These differences did not affect the sensitivity of expected humerus length as a marker of Down syndrome in our diverse population.

Adult↗

PubMed1996

Histomorphometric and angiographic analysis of the humerus in pigeons.

OBJECTIVE: To identify the vascular supply and resorption/formation activity of the humerus of pigeons. DESIGN: Pigeons were injected with the fluorochrome label oxytetracycline and, 5 days later, with the label calcein. 5 days after administration of the second fluorochrome, a wing from each bird was infused with a microparticle barium solution immediately after euthanasia and the chosen humerus was prepared for angiography while the opposite was prepared for histomorphometry. ANIMALS: 17 nine-month-old pigeons, consisting of 9 male and 8 female birds. PROCEDURE: At euthanasia, 1 wing was chosen for infusion and the barium solution was injected through a catheter in the brachiocephalic artery. Both humeruses were harvested. The infused humerus was decalcified, radiographed, and sectioned for H&E staining. The opposite humerus was sectioned and measured by use of a morphometric analyzing system to determine cross-sectional area, endosteal and periosteal perimeters, and percentage of perimeter containing a single and/or double label. RESULTS: All pigeons had an intramedullary arterial supply. The bones had a quiescent appearance histologically, consisting principally of lamellar bone with few osteospecialized cells, resorption surfaces, or osteons. Less than 10% of either the periosteal or endosteal surface acquired a fluorochrome label. CONCLUSIONS: The intramedullary vascular supply of the humerus is similar in structure to the vascular supply to mammalian bones. The humerus is, however, a quiescent bone in the sexually mature pigeon, with little remodeling activity present. CLINICAL RELEVANCE: The intramedullary blood supply may have an important role in the healing of humeral fractures in avian species.

Analysis of Variance↗

PubMed1996

Histomorphometric and angiographic analysis of bone healing in the humerus of pigeons.

OBJECTIVE: To evaluate the vascular supply and quantitatively compare the periosteal and endosteal callus formed during fracture healing. DESIGN: 36 pigeons were allotted to 2 groups. In each bird, 1 humerus was surgically osteotomized. The wing with the fractured humerus in birds of the first group was infused with a microparticle barium solution, and the humerus was harvested for angiography. Pigeons of the second group were injected with the labels oxytetracycline and calcein. The fractured humerus in each of these birds was harvested for histomorphometry. ANIMALS: 36 nine-month-old pigeons, consisting of 19 male and 17 female birds. PROCEDURE: 1 humerus from each of the 36 pigeons was osteotomized in the center of the bone by use of an obstetrical wire. All fractured wings were placed in a figure-of-8 bandage after surgery. The specimens harvested for angiography were decalcified, radiographed, and sectioned for H&E-stained tissue slides. Humeruses harvested for histomorphometry were cross-sectioned for tissue slides, which were measured, using a morphometric analyzing system for original and new bone areas. RESULTS: A continuous intramedullary circulation was not present at any point in the healing process, although 2 of the 42-day-old fractures had a bridging callus. Quantitatively, the periosteal surface formed the largest amount of callus, though the endosteal surface was also active. CONCLUSIONS: Reformation of the intramedullary circulation may not be imperative for osseous union of the pigeon humerus. Fluorochrome labels cannot be accurately measured at the fracture site. However, subjective evaluation of the endosteal surface indicates it is active during the fracture-healing process even though the periosteal surface provides the largest amount of callus formation. CLINICAL RELEVANCE: Figure-of-8 coaptation is contra-indicated for humeral fractures. The endosteal surface's contribution to the healing process should be considered when avian humeral fractures are stabilized.

Angiography↗

PubMedDate not supplied

Shoulder arthroplasty for the treatment of the sequelae of fractures of the proximal humerus.

The purpose of this multicenter study was to analyze the results of shoulder arthroplasty for the treatment of the sequelae of proximal humerus fractures and establish an updated classification system and treatment guidelines for these complex situations. Seventy-one sequelae of proximal humerus fractures were treated with shoulder replacement with the use of the same nonconstrained, modular, and adaptable prosthesis: the Aequalis prosthesis (Tornier Inc, St Ismier, France). The average time between initial fracture and shoulder arthroplasty was 5 years and 5 months. On the basis of anatomic classification schemes, sequelae were divided into 4 types: type 1, humeral head collapse or necrosis with minimal tuberosity malunion (40 cases); type 2, locked dislocations or fracture-dislocations (9 cases); type 3, nonunions of the surgical neck (6 cases); and type 4, severe malunions of the tuberosities (16 cases). The mean postoperative follow-up was 19 months (range, 12 to 48 months). Overall, the postoperative Constant score was excellent in 11 cases (16%), good in 19 cases (26%), fair in 18 cases (25%), and poor in 23 cases (33%). There were 18 complications (27%). Fifty-nine of 70 patients (81%) stated that they were satisfied with the result. The most significant factor affecting functional outcome was greater tuberosity osteotomy (P <.005). Regarding both surgical treatment and postoperative prognosis, we identify 2 categories of proximal humerus fracture sequelae: category 1, intracapsular/impacted fractures sequelae (associated with both cephalic collapse or necrosis [type 1] and chronic dislocation or fracture-dislocation [type 2]), in which an articulating joint can be reconstructed without a greater tuberosity osteotomy; and category 2, extracapsular/disimpacted fractures sequelae (associated with both surgical neck nonunions [type 3] and severe tuberosity malunions [type 4]) where the proximal humerus cannot be reconstructed without a greater tuberosity osteotomy. All of the excellent and good postoperative Constant scores were obtained in type 1 and 2, in which osteotomy of the greater tuberosity was not required. All patients in type 3 and 4, who underwent a greater tuberosity osteotomy, had either fair or poor results and did not regain active elevation above 90 degrees. We conclude that a greater tuberosity osteotomy is the most likely reason for poor and unpredictable results after shoulder replacement arthroplasty for the treatment of the complex sequelae of proximal humerus fractures. Shoulder arthroplasty for the treatment of the sequelae of fractures of the proximal humerus should be performed without an osteotomy of the greater tuberosity when possible. If prosthetic replacement is possible without an osteotomy, surgeons should accept the distorted anatomy of the proximal humerus and adapt the prosthesis and their technique to the modified anatomy. A modular and adaptable prosthesis with both adjustable offsets and inclination may allow surgeons to adapt to a large number of malunions and may help to avoid the troublesome greater tuberosity osteotomy in a higher proportion of cases.

Adult↗

PubMed1997

The contractile properties of the M. supracoracoideus In the pigeon and starling: a case for long-axis rotation of the humerus

Wing upstroke in birds capable of powered flight is kinematically the most complicated phase of the wingbeat cycle. The M. supracoracoideus (SC), generally considered to be the primary elevator of the wing, is a muscle with a highly derived but stereotyped morphology in modern flying birds. The contractile portion of the SC arises from a ventral sternum, but its tendon of insertion courses above the glenohumeral joint to insert on the dorsal surface of the humerus. To clarify the role of the SC during wing upstroke, we studied its contractile and mechanical properties in European starlings (Sturnus vulgaris) and pigeons (Columba livia), two birds with contrasting flight styles. We made in situ measurements of isometric forces of humeral elevation and humeral rotation and, in addition, measured the extent of unrestrained humeral excursion during stimulation of the muscle nerve. We also generated passive and active length-force curves for the SC of each species. Stimulation of the SC at humeral joint angles of elevation/depression and protraction/retraction coincident with the downstroke-upstroke transition and mid-upstroke produced substantially higher forces of long-axis rotation than elevation. When the humerus was allowed to move (rotate/elevate) during stimulation, we observed rotation about its longitudinal axis of up to 70-80 degrees , but humeral elevations of only 40-60 degrees above the horizontal (as measured in lateral view). In the active length-force experiments, we measured mean (+/-s.d.) maximal tetanic forces of 6.5+/-1.2 N for starlings (N=4) and 39.4+/-6.2 N for pigeons (N=6), unexpectedly high forces approximately 10 times body weight. The working range of the SC in both species corresponds to the ascending limb (but not the plateau) of the active length-force curve. The potential for greatest active force is high on the ascending limb at joint angles coincident with the downstroke-upstroke transition, a time when the humerus is depressed below the horizontal and rotated forward maximally. As the SC shortens to counterrotate and elevate the humerus during early upstroke, the potential for active force at shorter lengths declines at a relatively rapid rate. These findings reveal that the primary role of the SC is to impart a high-velocity rotation of the humerus about its longitudinal axis, which rapidly elevates the distal wing. This rapid twisting of the humerus is responsible for positioning the forearm and hand so that their subsequent extension orients the outstretched wing in the parasagittal plane appropriate for the subsequent downstroke. We propose that, at the downstroke-upstroke transition, variable levels of co-contraction of the M. pectoralis and SC interact to provide a level of kinematic control at the shoulder that would not be possible were the two antagonists to work independently. The lack of a morphologically derived SC in Late Jurassic and Early Cretaceous birds precluded a high-velocity recovery stroke which undoubtedly limited powered flight in these forms. Subsequent evolution of the derived SC capable of imparting a large rotational force to the humerus about its longitudinal axis was an important step in the evolution of the wing upstroke and in the ability to supinate (circumflex) the manus in early upstroke, a movement fundamental to reducing air resistance during the recovery stroke.

Journal Article↗

PubMed2001

Functional status of the paretic arm affects the loss of bone mineral in the proximal humerus after stroke: a 1-year prospective study.

The aim of this study was to evaluate the effect of decreased arm function after stroke on bone mineral density (BMD) in the proximal humerus. Twenty-five patients were evaluated 1 week after acute stroke and reevaluated 2 months, 7 months, and 1 year after the stroke. BMD of the proximal humerus was measured and the functional status of the paretic arm was assessed. Within 1 year the BMD decreased significantly in the proximal humerus at the paretic side. No significant BMD change was found at the nonparetic side. Patients with an initial completely paralyzed arm lost 27% (P <0.001), those with severe to moderate paresis lost 11% (P <0.001), and patients with minor or no paresis had no significant bone loss in the proximal humerus at the paretic side after 1 year. A statistically significant trend with initial arm function was found both 7 months and 1 year after the stroke at the paretic side (P <0.01). Patients who were paralyzed or had severe to moderate paresis both at inclusion and after 1 year had a larger 1-year bone loss in the proximal humerus than the patients who recovered and these who had only minor impairment throughout the study, 25%, 8%, and 5%, respectively (P-value for linear trend <0.001). We conclude that during the first year after stroke bone mineral is lost in the proximal humerus of the paretic arm, but that the loss depends on the initial degree of paresis. The loss may be prevented if arm function is regained.

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PubMed1998

Callus formation in the humerus compared with the femur and tibia during limb lengthening.

We investigated whether the callus formation in the humerus during the distraction period of limb lengthening proceeds at a higher rate than that in the femur and tibia. Ten achondroplastic patients underwent 3 bilateral humerus, 3 bilateral femur and 4 bilateral tibia lengthenings. To reduce the confounding effect of bone size, we used bone mineral apparent density (BMAD) to compare the three groups; this is a volumetric bone mineral density measurement. BMAD in the distracted callus space was evaluated at 8 weeks after the start of distraction using dual-energy X-ray absorptiometry (mean +/- SD; g/cm3): in the humerus (0.24 +/- 0.08) it was significantly higher than in the tibia (0.10 +/- 0.02), while there was no difference between the humerus and femur (0.35 +/- 0.11). We conclude that the callus formation in the humerus during the distraction period of limb lengthening proceeded at a significantly faster rate than in the tibia, but there was no significant difference between the humerus and femur.

Achondroplasia↗

PubMed1998

The operative management of a malignant proximal humerus tumor represented by secondary Paget's osteosarcoma.

PURPOSE: Malignant tumors at the proximal humerus are an operative challenge. Radical removal is a principal of tumor surgery but as much functionality as possible should be retained. These conditions often conflict so a compromise has to be reached. This paper proposes a solution to this dilemma, introducing an operative approach, with a new modular prosthesis, to a secondary Paget's osteosarcoma in the proximal humerus. METHODS AND RESULTS: A recently developed humerus modular prosthesis is described, which has been implanted into a patient with Paget's osteosarcoma. In these, mostly elderly, patients, successful operative therapy should combine radical removal with early mobilization. Paget's osteosarcoma is a recognized complication of the disease, and its prognosis is poor. In our patient, the implanted humerus prosthesis allowed a limb-saving procedure to be combined with radical removal of the tumor and postoperative early mobilization. A 3-month follow-up yielded good results with no recurrence of the disease and the patient had satisfactory movement. She was able to resume normal daily life shortly after the operation. CONCLUSION: Implantation of a modular prosthesis of the humerus may allow radical removal of a malignant tumor in that area while achieving early motion. In the literature, amputation is often advocated, as radical treatment with chemotherapy is not a successful option in this elderly patient group. We think the alternative use of a modular prosthesis of the humerus is possible in selected cases. We have encountered no other case in the literature where a limb-saving procedure attempts to preserve as much functionality as possible in Paget's osteosarcoma.

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