Surgical landmarks to determine humeral head retrotorsion for hemiarthroplasty in fractures

The bicipital groove as a landmark for humeral version reference during shoulder arthroplasty: a computed tomography study of normal humeral rotation

BACKGROUND

Accurate reproduction of humeral version is important in shoulder arthroplasty. Traditional referencing relative to the transepicondylar axis (TEA) is prone to error as it is absent on preoperative imaging and inaccurately reproduced intraoperatively. The bicipital groove is present on preoperative imaging and in the operative field and thus may be a useful landmark for accurate reproduction of humeral version.

MATERIALS AND METHODS

Two trained observers analyzed 101 full-humerus computed tomography scans of patients undergoing a myeloma screening protocol. Measurements of humeral retroversion relative to the TEA (angle A), humeral articular axis retroversion relative to the bicipital groove (angle B), and the bicipital groove axis relative to the TEA (angle C) were made with comparison of the measurement properties of each.

RESULTS

Humeral retroversion relative to the TEA was 23.7° ± 8° (range, 0.2°-48.7°; 95% confidence interval, 22°-26°). The humeral articular axis was retroverted to the bicipital groove axis (angle B) by 33.5° ± 9.4° (range, 15.5°-61.7°; 95% confidence interval, 32°-35°). Overall inter-rater reliability was 0.88.

DISCUSSION

Measurement of humeral head retroversion relative to the bicipital groove is not inferior to the gold-standard measurement. The bicipital groove is present both on preoperative imaging and in the operative field, making it a potential reference landmark for accurate reproduction of humeral version in shoulder arthroplasty.

Clinical relevance of the anatomy of the long head bicipital groove, an evidence-based review

Pathology in the bicipital groove can be a source of anterior shoulder pain. Many studies have compared treatment techniques for the long head biceps tendon (LHBT) without showing any clinically significant differences. As the LHBT is closely related to the bicipital groove, anatomical aspects of this groove could also be implicated in surgical outcomes. The aim of this review is to contribute to developing the optimal surgical treatment of LHBT pathology based on clinically relevant aspects of the bicipital groove. Medline/PubMed was systematically searched using key words "bicipital" and "groove" and combinations of their synonyms. Studies reporting on evolution, embryonic development, morphometry, vascularization, innervation, and surgical treatment of the LHBT and the bicipital groove were included. The length of the bicipital groove reported in the included studies ranged from 81.00 mm to 87.33 mm, width from 7.74 mm to 11.60 mm, and depth from 3.70 mm to 6.00 mm. The anatomy of the bicipital groove shows a bottleneck narrowing approximately two-thirds from superior. The transverse humeral ligament can constrain the bicipital groove and could be involved in anterior shoulder pain. When either LHBT tenotomy or tenodesis is performed, routinely releasing the transverse ligament could decrease postoperative anterior shoulder pain, which has frequently been reported in the literature. To avoid the bottle neck narrowing, a location below the bicipital groove may be preferred for biceps tenodesis over a more proximal tenodesis site. Level of evidence: IV.

Humeral Retroversion (Complexity of Assigning Reference Axes in 3D and Its Influence on Measurement): A Technical Note

Background

Humeral retroversion (RV) is important to the study of shoulder function and reconstruction. This study tests the hypothesis that clinically obtained computer tomography (CT) measurements for humeral RV (off-axis measurements) differ from those obtained after reformatting the image slice orientation so that the humeral shaft is perpendicular to the gantry (coaxial measurements) and explores deviations from true RV.

Materials and methods

A custom-built application created in Mathematica was used to explore the effect of altering the humeral orientation on slice angle acquisition by 3D imaging technologies, on the perceived angle of RV from the 2D-projection of the reference axes. The application allows for control of humeral axis orientation relative to image slice (3D) or plain of projection (2D) and humeral rotation. The effect of rotating a virtual model of one humerus around its own axis and in discrete anatomical directions on the measured RV angle was assessed.

Results

The coaxial measurement of humeral RV (31.2°) differed from off-axis measurement, with a maximum difference in measured RV of 50° in 45° of extension. The typical position of the humerus in a CT scan resulted in a difference in RV measurement up to 22°. Explorations of deviation led to the following outcomes, as divided by anatomic direction. Extension and abduction led to an underestimation, and flexion and adduction led to an overestimation of the RV-angle.

Conclusion

Measurements must be done consistently about the position and orientation of the humerus. Deviation in the humeral alignment of as little as 10° can distort the measurement of version up to 15°.

How to cite this article

van de Bunt F, Pearl ML, van Noort A. Humeral Retroversion (Complexity of Assigning Reference Axes in 3D and Its Influence on Measurement): A Technical Note. Strategies Trauma Limb Reconstr 2020;15(2):69-73.

A Novel Method for the Approximation of Humeral Head Retrotorsion Based on Three-Dimensional Registration of the Bicipital Groove

BACKGROUND

The accurate restoration of premorbid anatomy is key for the success of reconstructive surgeries of the proximal part of the humerus. The bicipital groove has been proposed as a landmark for the prediction of humeral head retrotorsion. We hypothesized that a novel method based on bilateral registration of the bicipital groove yields an accurate approximation of the premorbid anatomy of the proximal part of the humerus.

METHODS

Three-dimensional (3D) triangular surface models were created from computed tomographic data of 100 paired humeri (50 cadavers). Segments of the distal part of the humerus and the humeral shaft of prespecified lengths were defined. A surface registration algorithm was applied to superimpose the models onto the mirrored contralateral humeral model based on the defined segments. We evaluated the 3D proximal humeral contralateral registration (p-HCR) errors, defined as the difference in 3D rotation of the humeral head between the models when superimposed. For comparison, we quantified the landmark-based retrotorsion (LBR) error, defined as the intra-individual difference in retrotorsion, measured with a landmark-based 3D method.

RESULTS

The mean 3D p-HCR error using the most proximal humeral shaft (bicipital groove) segment for the registration was 2.8° (standard deviation [SD], 1.5°; range, 0.6° to 7.4°). The mean LBR error of the reference method was 6.4° (SD, 5.9°; range, 0.5° to 24.0°).

CONCLUSIONS

Bilateral 3D registration of the bicipital groove is a reliable method for approximating the premorbid anatomy of the proximal part of the humerus.

CLINICAL RELEVANCE

The accurate approximation of the premorbid anatomy is a key for the successful restoration of the premorbid anatomy of the proximal part of the humerus.

A New Stem Guide and a Tuberosity Anchoring "Lasso" System for Shoulder Hemiarthroplasty in the Treatment of Complex Proximal Humerus Fractures

Hemiarthroplasty implantation for proximal humerus fracture is challenging. In case of young demanding patients with functional rotator cuff, humeral head replacement is an option if open reduction internal fixation is not a viable solution. The criteria for success in terms of clinical outcomes and longevity are anatomic healing of the tuberosities and stem positioning (restoring correct height, version, and axis). The purpose of this article is to describe a technique including a new stem guide and a tuberosity anchor "lasso" system for the implantation of hemiarthroplasty in complex proximal humerus fractures. A standard delto-pectoral approach is performed. After humeral head removal and tuberosity mobilization and debridement, a stem-positioning system guarantees correct height and version of the humeral stem, established after anatomic reduction of the greater tuberosity. A centering device is added on the humeral stem to prevent any varus or valgus. Fixation of the tuberosities is achieved with 6 nonabsorbable sutures fixed on a polyester "lasso" anchoring system circling the humerus, respecting the direction of rotator cuff tendons and adding double circumferential tightening. After reduction of the implant, stability, and passive range of motion are assessed intraoperatively and fluoroscopic control of the prosthesis is performed. The patient is maintained in a sling in neutral rotation and passive motion is started after 4 weeks; active motion is allowed after 2 months. We believe this surgical technique could help limit complications and prevent revision of the humeral stem in case of further conversion to reverse shoulder arthroplasty.

Prediction of the pre-morbid 3D anatomy of the proximal humerus based on statistical shape modelling

Aims

Restoring the pre-morbid anatomy of the proximal humerus is a goal of anatomical shoulder arthroplasty, but reliance is placed on the surgeon’s experience and on anatomical estimations. The purpose of this study was to present a novel method, ‘Statistical Shape Modelling’, which accurately predicts the pre-morbid proximal humeral anatomy and calculates the 3D geometric parameters needed to restore normal anatomy in patients with severe degenerative osteoarthritis or a fracture of the proximal humerus.

Materials and Methods

From a database of 57 humeral CT scans 3D humeral reconstructions were manually created. The reconstructions were used to construct a statistical shape model (SSM), which was then tested on a second set of 52 scans. For each humerus in the second set, 3D reconstructions of four diaphyseal segments of varying lengths were created. These reconstructions were chosen to mimic severe osteoarthritis, a fracture of the surgical neck of the humerus and a proximal humeral fracture with diaphyseal extension. The SSM was then applied to the diaphyseal segments to see how well it predicted proximal morphology, using the actual proximal humeral morphology for comparison.

Results

With the metaphysis included, mimicking osteoarthritis, the errors of prediction for retroversion, inclination, height, radius of curvature and posterior and medial offset of the head of the humerus were 2.9° (± 2.3°), 4.0° (± 3.3°), 1.0 mm (± 0.8 mm), 0.8 mm (± 0.6 mm), 0.7 mm (± 0.5 mm) and 1.0 mm (± 0.7 mm), respectively. With the metaphysis excluded, mimicking a fracture of the surgical neck, the errors of prediction for retroversion, inclination, height, radius of curvature and posterior and medial offset of the head of the humerus were 3.8° (± 2.9°), 3.9° (± 3.4°), 2.4 mm (± 1.9 mm), 1.3 mm (± 0.9 mm), 0.8 mm (± 0.5 mm) and 0.9 mm (± 0.6 mm), respectively.

Conclusion

This study reports a novel, computerised method that accurately predicts the pre-morbid proximal humeral anatomy even in challenging situations. This information can be used in the surgical planning and operative reconstruction of patients with severe degenerative osteoarthritis or with a fracture of the proximal humerus. Cite this article: Bone Joint J 2017;99-B:927–33.

Linear relationship between lateralization of the bicipital groove and humeral retroversion and its link with the biepicondylar humeral line. Anatomical study of seventy cadaveric humerus scans

INTRODUCTION

Morphological studies of the humerus have shown that the position of the bicipital groove varies with the individual and the retroversion of the humeral head. Depending on the authors, these two parameters are independent or associated. This study evaluated the relationship between the humeral head axis and its retroversion and the bicipital groove relative to the humeral biepicondylar line.

MATERIALS AND METHODS

Seventy cadaveric humeri were scanned to obtain 3D reconstructions. Views of the 3D reconstruction from above showed the bicondylar line, the bicipital groove and the humeral head on a single image. After measuring the humeral retroversion angle and the bicipital groove angle relative to the bicondylar line, we assessed the relationship between these two angles with Pearson's correlation coefficient.

RESULTS

Pearson's correlation coefficient indicated a significant linear correlation between the angle of the groove and the angle of humeral retroversion based on the 70 cadaveric humeral bones (the p-value was 7.5^10-7, the correlation coefficient was -0.5515, and the 95% confidence interval was (-0.6962; -0.3636)). Our study thus demonstrates that the less lateralized the bicipital groove is, the greater the humeral retroversion will be.

CONCLUSION

We demonstrated a linear relationship between humeral head retroversion and bicipital groove lateralization. Within our reliability interval, this relationship can be used in clinical practice to evaluate retroversion without resorting to CT of the entire humerus.

Analyzing on the location of the bicipital groove for alignment in shoulder arthroplasty of Chinese

BACKGROUND

Many anthropometric studies of the normal glenohumeral relationship have been performed for the implant design and to identify reference points for the correct placement of the prosthesis in glenohumeral joint replacement. However, whether those implantation marks, which adopted from European or American, can achieve the same precision to Eastern Asian, specifically Chinese is still unknown.

MATERIALS AND METHODS

One hundred eighty healthy were scanned using CT. Their humeri were measured to determine humeral head retroversion and its relation to the location of the bicipital groove. The angle between the transepicondylar axis and the line connected the centre of the head sphere and the lateral lip point of the bicipital groove, and the plane through the humerus shaft axis and the lateral lip of the bicipital groove in the horizontal plane were measured and denoted by angle-α and angle-β, respectively. The biceps distance (BD) from the lateral lip of the bicipital groove proximally to the axis of humeral head in the horizontal plane was also measured.

RESULTS

The average angle α and β was 40.08° (±11.15°) and 42.19° (±12.64°). The average BD was 7.15 mm (range 0.87-13.94 mm; SD 2.55 mm). The linear relationship between humeral head retroversion and the bicipital groove angle α can expressed as α = 0.7125 × retroversion+24.8128 (R² = 0.5956). If the centre of the lateral aspect of the stem has a posteriorly offset of 20° from the lateral lip of the bicipital groove, the component would have a proximal 20° of retroversion.

CONCLUSION

The results indicate that the bicipital groove can be used as a landmark for prosthetic stem positioning in shoulder arthroplasty. Moreover, it is different from the current standard technique of cutting the proximal humerus at 30° of retroversion with the epicondyles or forearm used as a guide.

Computer algorithms for three-dimensional measurement of humeral anatomy: analysis of 140 paired humeri

BACKGROUND

In the presence of severe osteoarthritis, osteonecrosis, or proximal humeral fracture, the contralateral humerus may serve as a template for the 3-dimensional (3D) preoperative planning of reconstructive surgery. The purpose of this study was to develop algorithms for performing 3D measurements of the humeral anatomy and further to assess side-to-side (bilateral) differences in humeral head retrotorsion, humeral head inclination, humeral length, and humeral head radius and height.

METHODS

The 3D models of 140 paired humeri (70 cadavers) were extracted from computed tomographic data. Geometric characteristics quantifying the humeral anatomy in 3D were determined in a semiautomatic fashion using the developed computer algorithms. The results between the sides were compared for evaluating bilateral differences.

RESULTS

The mean bilateral difference of the humeral retrotorsion angle was 6.7° (standard deviation [SD], 5.7°; range, -15.1° to 24.0°; P = .063); the mean side difference of the humeral head inclination angle was 2.3° (SD, 1.8°; range, -5.1° to 8.4°; P = .12). The side difference in humeral length (mean, 2.9 mm; SD, 2.5 mm; range, -8.7 mm to 10.1 mm; P = .04) was significant. The mean side difference in the head sphere radius was 0.5 mm (SD, 0.6 mm; range, -3.2 mm to 2.2 mm; P = .76), and the mean side difference in humeral head height was 0.8 mm (SD, 0.6 mm; range, -2.4 mm to 2.4 mm; P = .44).

CONCLUSIONS

The contralateral anatomy may serve as a reliable reconstruction template for humeral length, humeral head radius, and humeral head height if it is analyzed with 3D algorithms. In contrast, determining humeral head retrotorsion and humeral head inclination from the contralateral anatomy may be more prone to error.

Repositioning of the humeral tuberosities can be guided by pectoralis major insertion

In complex proximal humerus fractures, positioning of the tuberosities can be a challenge. This study demonstrates the constant angle between the pectoralis major (PM) and the medial lip of the bicipital groove (BG) on the horizontal axial plane. This angle can be used to determine the rotation, as well as the positioning of the tuberosities, when planning a hemiarthroplasty or a reconstruction. Thirty-one shoulder MRIs were reviewed by three independent observers. The measurements were taken by superposing the axial cut of the proximal humerus, at the level of the distal bicipital groove, and the cut at the top of the PM insertion. By aligning the centers of rotation, we could determine the arcs of rotation between the insertion of the PM and the lips of the medial and lateral bicipital groove (MBG and LBG). Both angles were compared in terms of reliability, reproducibility, and precision. The mean PM-MBG angle was 3.7° [standard deviation (SD) 14.7°] and 27.4° (SD 14.4°) for the PM-LBG angle. We obtained good and very good intra-class correlation coefficient (ICC) results for inter- (0.675) and intra-observer (0.793) reliabilities on the medial angle, plus excellent results for the lateral angle (inter-observers 0.962 and intra-observer 0.895). This study demonstrates that the repositioning of humeral tuberosities can be guided by pectoralis major insertion. This will help achieve proper positioning of the metaphysis in relation to the diaphysis during surgery for complex proximal humerus fractures.

A review of management options for proximal humeral fractures

Proximal humeral fractures are common and although the majority can be managed non-operatively, the optimal treatment of displaced or complex fractures remains controversial. Non-operative treatment is typically selected for minimally displaced fractures where union rates are high and good or excellent outcomes can be expected in approximately 80% of cases. The aims of surgical fixation are to restore articular surface congruency, alignment and the relationship between the tuberosities and the humeral head. Hemiarthroplasty provides patients with reliable pain relief and its indications include fracture dislocations, humeral head splitting fractures and some three- and four- part fractures. The key areas of surgical technique that influence functional outcome include correctly restoring the humeral height, humeral version and tuberosity position. Function, however, is poor if the tuberosities either fail to unite or mal-unite. The interest in reverse shoulder arthroplasty as an alternative option has therefore recently increased, particularly in older patients with poor bone quality and tuberosity comminution. The evidence supporting this, however, is currently limited to multiple case series with higher level studies currently underway.

An Unusual Disengagement of the Humeral Head Component after Hemiarthroplasty: A Case Report Presentation

Introduction:

Proximal humeral fractures account for 4% to 5% of all fractures. Complex proximal humeral fractures with displaced three- and four-part fragments, humeral head splits and fracture-dislocations are more difficult to treat. In older patients, because of poor bone quality, hemiarthroplasty is often the indicated treatment.

Case Report:

One such case of a 73-year-old woman is presented here. The patient presented with a four-part fracture of the proximal humerus, with displacement of the humeral head. Hemiarthroplasty was done in the right shoulder. At postoperative 20 days, during physical therapy, the humeral head component of the prosthesis disengaged and a second operation was necessary. A deltopectoral approach was repeated using the previous incision. The humeral stem was seen to be well-fixed into the bone so the humeral head was changed for a new one of the same size. At two years, the dominant right side had active, painless ROM.

Conclusion:

The management and two-year follow-up of this case is reported here, which was the first to occur at our institution.

Accuracy of glenoid component placement in total shoulder arthroplasty and its effect on clinical and radiological outcome in a retrospective, longitudinal, monocentric open study

Background

The success of Total Shoulder Arthroplasty (TSA) is believed to depend on the restoration of the natural anatomy of the joint and a key development has been the introduction of modular humeral components to more accurately restore the patient’s anatomy. However, there are no peer-reviewed studies that have reported the degree of glenoid component mal-position achieved in clinical practice and the clinical outcome of such mal-position. The main purpose of this study was to assess the accuracy of glenoid implant positioning during TSA and to relate it to the radiological (occurrence of radiolucent lines and osteolysis on CT) and clinical outcomes.

Methods

68 TSAs were assessed with a mean follow-up of 38+/−27 months. The clinical evaluation consisted of measuring the mobility as well as of the Constant Score. The radiological evaluation was performed on CT-scans in which metal artefacts had been eliminated. From the CT-scans radiolucent lines and osteolysis were assessed. The positions of the glenoid and humeral components were also measured from the CT scans.

Results

Four position glenoid component parameters were calculated The posterior version (6°±12°; mean ± SD), the superior tilt (12°±17°), the rotation of the implant relative to the scapular plane (3°±14°) and the off-set distance of the centre of the glenoid implant from the scapular plane (6±4 mm). An inferiorly inclined implant was found to be associated with higher levels of radiolucent lines while retroversion and non-neutral rotation were associated with a reduced range of motion.

Conclusion

this study demonstrates that glenoid implants of anatomic TSA are poorly positioned and that this malposition has a direct effect on the clinical and radiological outcome. Thus, further developments in glenoid implantation techniques are required to enable the surgeon to achieve a desired implant position and outcome.

A three-dimensional analysis of humeral head retroversion

INTRODUCTION

The anatomic neck of the humerus is used as a reference for the osteotomy in shoulder arthroplasty. Resection along the anterior portion of the cartilage/metaphyseal border is assumed to remove a cap of a sphere that can accurately be replaced with a spherical prosthetic implant oriented precisely to the original articular surface. The aim of this study was to determine the variability in retroversion of the cartilage/metaphyseal interface in the axial plane.

METHODS

Surface topography data for 24 arms from deceased donors were collected by using a hand-held digitizer and a surface laser scanner. Data were combined into the same coordinate system and graphically presented. The humeral head was divided into 6 sections in the axial plane and the retroversion angle measured at each level with reference to the transepicondylar axis at the elbow.

RESULTS

The mean retroversion of the humeral head at the midpoint between the superior and inferior margins was 18.6°. The angle increased as the position of the measurement moved superiorly to 22.5°. In contrast, the retroversion angle reduced as the position of measurement moved more inferiorly to 14.3°.

DISCUSSION

The results suggest that the cartilage/metaphyseal interface is not circular encompassing a spherical cap of a sphere. Furthermore, there appears to be a clockwise torsion of the cartilage/metaphyseal interface about the transverse axis from its medial to lateral aspect.

CONCLUSION

The cartilage/metaphyseal interface shows a degree of variability that makes it an unreliable landmark to perform an osteotomy when the anterior aspect of the interface is used.

Hemiarthroplasty versus angle-stable locking compression plate osteosynthesis in the treatment of three- and four-part fractures of the proximal humerus in the elderly: design of a randomized controlled trial

BACKGROUND

The optimal surgical management of dislocated three- and four-part fractures of the proximal humerus in elderly patients remains unclear. Most used techniques are hemiarthroplasty and angle-stable locking compression plate osteosynthesis. In the current literature there is no evidence available presenting superior results between hemiarthroplasty and angle-stable locking compression plate osteosynthesis in terms of speed of recovery, pain, patient satisfaction, functional outcome, quality of life or complications.

METHODS/DESIGN

A randomized controlled multicenter trial will be conducted. Patients older than 60 years of age with a dislocated three- or four-part fracture of the proximal humerus as diagnosed by X-rays and CT-scans will be included. Exclusion criteria are a fracture older than 14 days, multiple comorbidity, multitrauma, a pathological fracture, previous surgery on the injured shoulder, severely deranged function caused by a previous disease, "head-split" proximal humerus fracture and unwillingness or inability to follow instructions. Participants will be randomized between surgical treatment with hemiarthroplasty and angle-stable locking compression plate osteosynthesis. Measurements will take place preoperatively and 3 months, 6 months, 9 months, 12 months and 24 months postoperatively. Primary outcome measure is speed of recovery of functional capacity of the affected upper limb using the Disabilities of Arm, Shoulder and Hand score (DASH). Secondary outcome measures are pain, patient satisfaction, shoulder function, quality of life, radiological evaluation and complications. Data will be analyzed on an intention-to-treat basis, using univariate and multivariate analyses.

DISCUSSION

Both hemiarthroplasty and angle-stable locking compression plate osteosynthesis are used in the current treatment of dislocated three-and four-part fractures of the proximal humerus. There is a lack of level-1 studies comparing these two most-used surgical treatment options. This randomized controlled multicenter trial has been designed to determine which surgical treatment option provides the fastest recovery of functional capacity of the affected upper limb, and will provide better outcomes in pain, satisfaction, shoulder function, quality of life, radiological evaluation and complications.

TRIAL REGISTRATION NUMBER

The trial is registered in the Netherlands Trial Registry (NTR2461).

Prediction of the rotational state of the humerus by comparing the contour of the contralateral bicipital groove: Method for intraoperative evaluation

BACKGROUND

Accurate reduction of rotational displacement for transverse or comminute fracture of humeral shaft fracture is difficult during operation. The purpose of this study was to evaluate the reliability of the bicipital groove as a point of reference for the prediction of the rotational state of the humerus on two dimensional images of C-arm image intensifier during operation for humeral shaft fractures.

MATERIALS AND METHODS

One hundred subjects, 62 male, 38 female, aged 22-53 years were recruited contralateral bicipital groove on the 45 degrees externally rotational standard anterior-posterior view recorded before surgery. Three observers, watched only contour of bicipital groove in monitor of C-arm image intensification with naked eye without looking at the subject and predicted rotational state of the humerus by comparing the contour of the opposite side of bicipital groove. The angle of discrepancy from real rotational position was then assessed.

RESULTS

The mean (SD), angular discrepancy between the neutral point and the predicted angle was 3.4°(±2.7°). A value within 5° was present in 72% of cases. All observations were within 15°. There was no interobserver variation (P = 0.47). The intraclass correlation coefficient (ICC) was 0.847.

CONCLUSION

Contour of the bicipital groove on simple radiograph was a useful landmark. Comparing the contour of the bicipital groove in the 45 degrees externally rotational standard view bilaterally, was an effective method for reduction of rotational displacement of the humerus.

Revision total shoulder arthroplasty for painful glenoid arthrosis after humeral head replacement: the posttraumatic shoulder

HYPOTHESIS

This study was conducted to test the hypothesis that patients would have improved pain and range of motion after conversion total shoulder arthroscopy but that overall outcome would be substantially affected by the need for removal of the humeral component and associated alterations of bony anatomy or soft tissue deficiencies.

MATERIALS AND METHODS

Thirty-four patients (34 shoulders) with HHR after a proximal humeral fracture underwent revision total shoulder arthroplasty for painful glenoid arthrosis, with mean follow-up of 9.4 years (range, 2.3-20.4 years). After initial review, repeat analysis was performed based on the complexity of osseous (humeral stem revision) and soft tissue management, including rotator cuff tear, greater tuberosity resorption, malunion or nonunion, or instability.

RESULTS

Overall, patients had reduction in pain (P = .0001), and improved active abduction (P = .05) and external rotation (P = .0005). Less improvement in active abduction was documented in patients who required soft tissue management (P = .03). Results of the modified Neer rating documented 3 excellent, 9 satisfactory, and 22 unsatisfactory results (motion deficiencies in 14). Kaplan-Meier survival analysis free of repeat revision was 100% at 1 year, 96.8% at 5 years (95% confidence interval, 90%-100%), and 92.2% at 10 years (95% confidence interval, 82% to 100%).

DISCUSSION

Conversion total shoulder arthroplasty is effective for addressing painful glenoid arthrosis after primary HHR for a proximal humeral fracture, with or without the need to change the humeral component. However, active motion may not improve in patients with rotator cuff tearing, a greater tuberosity nonunion, malunion, or resorption.

Metaversion can reliably predict humeral head version: a computed tomography-based validation study

HYPOTHESIS

Circumstances occur when the determination of anatomic humeral head version is difficult. In the setting of irreparable proximal humeral fracture, there are few reliable intraoperative landmarks to determine anatomic humeral head version. This study tested our hypothesis that the metaphyseal version (metaversion) is a landmark that can assist with correct head version and used computed tomography (CT) to evaluate its reliability as a predictor of anatomic version.

MATERIALS AND METHODS

CT scans from 50 consecutive patients (20 women, 30 men) were examined using commercial software. Patients were a mean age of 46 years (range, 17-85 years). Exclusion criteria included previous fracture, arthritis, or humeral deformity. The metaversion and humeral head version were measured. Measurements were conducted independently by 2 surgeons blinded to the results of the other. Interobserver and intraobserver reliability was calculated using intraclass correlation.

RESULTS

The mean difference between the metaversion and the humeral head version was 2.5° (95% confidence interval [CI], 0.9°-3.9°). The mean difference between metaversion and humeral head version was 1.8° (95% CI, 0.0°-3.6°) in women, 2.9° (95% CI, 0.6°-5.1°) in men, 2.4° (95% CI: 0.6°-4.1°) in right shoulders, and 2.5° (95% CI, -0.1° to 5.1°) in left shoulders. Interrater and intrarater reliability was excellent, 0.97 and 0.98, respectively.

CONCLUSIONS

Proximal humeral metaphyseal version (metaversion) is an accurate predictor of ipsilateral humeral head version.

Shoulder arthroplasty for acute proximal humerus fracture

Proximal humerus fracture devascularizing the humeral head may require management by prosthesis. Hemiarthroplasty is a logical attitude in such cases, but analysis of functional results and complications has identified a certain number of risk factors limiting indications. Strict analysis of patient characteristics and of fracture type is an essential prerequisite to deciding against treatment by immobilization or osteosynthesis. Results in hemiarthroplasty are primarily dependent on respecting the rules of the art, which aim at stable anatomic osteosynthesis of the surrounding structures so as to restore normal shoulder function. The critical steps are the adjustment of implant height and retroversion, reduction and fixation of tuberosities and good management of the postoperative course. The recent development of fracture-dedicated shoulder implants should improve results. In elderly patients, when local conditions are unsuitable to hemiarthroplasty, a reverse prosthesis may be used, with an adapted surgical technique. Whatever the type of prosthesis, implantation for proximal humerus fracture is a demanding operation with definitive impact on the functional evolution of the shoulder.

Attachments of muscles as landmarks for implantation of shoulder hemiarthoplasty in fractures

BACKGROUND

The attachments of muscles and the position of the humeral head are important for a good functional outcome of shoulder hemiarthroplasties after displaced fractures of the proximal humerus. Deviations in the attachments and changes in their spatial position with respect to the humeral head during surgical reconstruction change the biomechanics and reduce the range of motion of the should joint postoperatively.

METHODS AND RESULTS

We used 198 humerus preparations and using 3-dimensional analysis measured the angular relationships between the humeral head axis and medial margin of the greater tuberosity (11.9 degrees +/- 9.1 degrees ), lateral margin of the lesser tuberosity (48.0 degrees +/- 7.8 degrees ), and the crest of the greater tuberosity (27.1 degrees +/- 9.6 degrees ).

CONCLUSION

This study provides average values of the positions of the greater and lesser tuberosities with respect to the humeral head axis. We show that the greater and lesser tuberosities are more reliable than the transepicondylar line for reconstruction of humeral head retroversion.

LEVEL OF EVIDENCE

Basic Science.

Lesser tuberosity is more reliable than bicipital groove when determining orientation of humeral head in primary shoulder arthroplasty

PURPOSE

The objective of the study was to provide statistical evaluation of position of bone landmarks of proximal humerus in relation to transepicondylar line and find out which one is the most suitable for setup of the head retroversion in case of humeral head destruction.

METHODS

We measured 185 dry humeral preparations (92 left, 93 right). Structures of interest on the proximal humerus were marked with pointers of custom made steel frame. Angular relationships between the humeral head axis and medial margin of the greater tuberosity, lateral margin of the lesser tuberosity, bicipital groove, and crest of the greater tuberosity were evaluated with respect to intramedullary axis of the proximal humeral shaft.

RESULTS

The angle between the humeral head axis and medial margin of greater tuberosity was 11.5 +/- 9.0 degrees , the angle between the lateral margin of the lesser tuberosity and the axis was 47.5 +/- 7.4 degrees , the angle between the bicipital groove and the axis was 31.6 +/- 8.8 degrees at the level of the humeral head. The angle between the crest of the greater tuberosity and the axis was 26.6 +/- 9.6 degrees in plane of the surgical neck.

CONCLUSIONS

We statistically proved that the lateral margin of lesser tuberosity is more reliable than the bicipital groove; medial margin of the greater and transepicondylar line for reconstruction of humeral head retroversion. We suggest that the lesser tuberosity should be used to determine the retroversion, especially in cases when the margin of humeral head was destructed.

Tuberosity position correlates with fatty infiltration of the rotator cuff after hemiarthroplasty for proximal humeral fractures

HYPOTHESIS

This study investigates the correlation between tuberosity positioning, fatty infiltration of the rotator cuff, and clinical outcome after hemiarthroplasty for proximal humeral fracture.

MATERIALS AND METHODS

Twenty patients with a mean age of 70.8 +/- 9.9 years were evaluated at a mean of 19.8 +/- 9.4 months. Evaluation included assessment of the Constant score (CS); Disabilities of the Arm, Shoulder and Hand (DASH) score; radiographic evaluation; and computed tomography to classify healing of the tuberosities and changes in the rotator cuff. Fatty degeneration of the cuff was classified according to the Goutallier classification as stage 0 to 4. Tuberosity positioning was classified as mal-positioning of less than 0.5 cm., 0.5 to 1 cm., >1.0 cm., or not healed.

RESULTS

The mean Constant Score (CS) of patients with greater tuberosity displacement of <0.5 cm was significantly higher than the CS of patients with > or =0.5 cm displacement and non-united greater tuberosities. The CS of patients with greater tuberosity displacement of 0.5 to 1 cm was significantly higher than that in patients with non-united greater tuberosities. For the lesser tuberosity, patients with displacement of <0.5 cm showed significantly higher outcome scores than patients with displacement of >1 cm and non-united lesser tuberosities. There was a significant correlation between fatty infiltration of the supraspinatus and infraspinatus muscles and greater tuberosity malposition and between fatty infiltration of the subscapularis and lesser tuberosity malposition.

CONCLUSION

Fatty infiltration of the cuff was significantly associated with lower clinical scores. Tuberosity positioning and healing are critical for improved clinical outcomes after hemiarthroplasty for proximal humeral fractures.

The pectoralis major tendon as a reference for restoring humeral length and retroversion with hemiarthroplasty for fracture

The success of anatomic reattachment of the tuberosities in proximal humeral fractures, treated with hemiarthroplasty, correlates with functional results. The purpose of this study was to determine the value of the upper edge of the pectoralis major insertion (PMI) as a landmark to establish the proper height and version of hemiarthroplasty implanted for proximal humeral fractures. Twenty cadaveric humeri were studied by CT scan to analyze the relationship between the PMI and humeral height and retroversion. The mean distance from the PMI to the tangent to the humeral head was 5.64 cm. The mean distance of the PMI to the posterior fin of the prosthesis was 1.06 cm. The mean angle between the PMI and the posterior fin of the prosthesis was 24.65 degrees. The upper edge of the pectoralis major insertion constitutes a reproducible reference point to restore proper humeral height and retroversion in hemiarthroplasty for proximal humeral fracture.

Reconstruction of humeral length and centering of the prosthetic head in hemiarthroplasty for proximal humeral fractures

Anatomic reconstruction of humeral length in hemiarthroplasty for complex proximal humeral fractures is difficult because reliable surgical landmarks are missing or are destroyed by the fracture. The pectoralis major tendon is a reliable landmark to determine prosthetic height intraoperatively. This study analyzed the clinical outcome, reconstruction of humeral length, centering of the prosthetic head in the glenoid, and tuberosity positioning and healing, using the pectoralis major tendon as a reference intraoperatively. The study included 30 patients. In 21 patients (group 1), humeral length reconstruction was performed using the pectoralis major tendon as a reference; in 9 (group 2), this reference was not used. Patients underwent a clinical and radiologic evaluation at a mean of 22.7 months. Group 1 showed significantly better results in clinical and radiologic values, especially in anatomic reconstruction of humeral length, than group 2. Clinical outcome depended significantly on greater tuberosity healing and centering of the prosthetic head in the glenoid.

[Primary hemiarthroplasty in proximal humerus fractures]

The surgical treatment of complex proximal humerus fractures is still a great challenge. Not all fracture types can be successfully reconstructed. Indications for a primary joint replacement arise from critical fracture patterns and defined predictors of ischemia in the elderly (age >60 years). If good functional results are to be achieved a soft-tissue-preserving surgical technique, secure tuberosity attachment and accurate soft tissue balancing of the rotator cuff, correct restoration of height, retrotorsion and offset, and appropriate physiotherapy afterwards are essential. In multicentre studies in patients who had undergone primary hemoarthroplasty average Constant-Murlay Scores of 56.0-73.5 point were recorded. At follow-up, 79% of the patients reported only mild pain or none at all, and the ROM was acceptable (41.9% anteversion >90 degrees , 34.7% abduction >90 degrees ). Generally, subjective evaluations were much better than the objective results.The incidence of complications after humeral head replacement is still relatively high, whereas the 10-year survival rate of shoulder hemiarthroplasties has been found in a recent study to be 100%.

Medial reconstruction technique in the treatment of complex fractures of humeral proximal epiphysis with SMR prosthetic modular system

Prosthetic treatment of complex fractures of humeral proximal meta-epiphysis is a very complex surgery that often does not lead to satisfactory results. Indeed, although in the last 35 years since Neer's studies some progress has been made in the knowledge of the anatomy of humeral meta-epiphysis proximal portion, surgical technique and prosthetic design, in the literature we find non-homogeneous experiences regarding the clinical-functional results. At the same time, such experiences agree as far as pain relief is concerned. We report our experience in the treatment of complex fractures of humeral proximal epiphysis with SMR (Lima Lto, San Daniele, Italy) prosthetic system, using our surgical technique of anatomical reconstruction, starting from the medial neck. The case histories, 35 patients, 30 women and 5 men, aged between 56 and 79, were reported in the observation period between April 2000 and February 2005. In 20 cases the right shoulder was treated and in 15 the left one. At the follow-up the patients were assessed clinically by the average Constant Score and also by X-rays and CT scan in order to measure the prosthesis height, its off-set and retroversion.

CT scan method accurately assesses humeral head retroversion

Humeral head retroversion is not well described with the literature controversial regarding accuracy of measurement methods and ranges of normal values. We therefore determined normal humeral head retroversion and assessed the measurement methods. We measured retroversion in 65 cadaveric humeri, including 52 paired specimens, using four methods: radiographic, computed tomography (CT) scan, computer-assisted, and direct methods. We also assessed the distance between the humeral head central axis and the bicipital groove. CT scan methods accurately measure humeral head retroversion, while radiographic methods do not. The retroversion with respect to the transepicondylar axis was 17.9 degrees and 21.5 degrees with respect to the trochlear tangent axis. The difference between the right and left humeri was 8.9 degrees. The distance between the central axis of the humeral head and the bicipital groove was 7.0 mm and was consistent between right and left humeri. Humeral head retroversion may be most accurately obtained using the patient's own anatomic landmarks or, if not, identifiable retroversion as measured by those landmarks on contralateral side or the bicipital groove.

Neer Award 2006: Biomechanical assessment of inferior tuberosity placement during hemiarthroplasty for four-part proximal humeral fractures

Tuberosity malpositioning commonly occurs and is associated with a decline in clinical function after prosthetic shoulder reconstruction for proximal humeral fractures. This study assesses the biomechanical effects of inferior tuberosity position on glenohumeral joint forces and humeral head position at multiple positions. Eight fresh-frozen cadaveric shoulders were tested. Hemiarthroplasty was performed with preservation of anatomic tuberosity height and with 10 mm and 20 mm of inferior tuberosity displacement. The rotator cuff, deltoid, pectoralis major, and latissimus dorsi muscles were statically loaded. Contact forces and humeral head position were recorded within a functional range of motion. Glenohumeral joint forces shifted significantly superiorly (P < .05) at 30 degrees of abduction after both 10 mm and 20 mm of tuberosity displacement. At 60 degrees of glenohumeral abduction, glenohumeral joint forces remained significantly altered after tuberosity displacement of 10 mm and 20 mm compared with the intact height (P < .005). This study demonstrates that, during hemiarthroplasty performed for proximal humeral fractures, malpositioning the tuberosities inferiorly results in significant superior glenohumeral joint force displacement. These findings suggest that the mechanical advantage of the shoulder abductor muscles is compromised with inferior tuberosity malpositioning and may help to explain inferior functional results seen in these patients.

Reattachment of the tuberosities with cable wires and bone graft in hemiarthroplasties done for proximal humeral fractures with cable wire and bone graft: 58 patients with a 22-month minimum follow-up

OBJECTIVE

The stability of 2 fixation techniques for the tuberosities in patients with 3- or 4-part proximal humerus fractures treated with hemiarthroplasties was compared.

DESIGN

Retrospective review of a nonrandomized sequential series of patients.

SETTING

Level I university orthopaedic surgery department.

PATIENTS

A consecutive series of 58 patients (average age, 64 years) from 1990 to 1999 with 3- and 4-part fractures of the proximal humerus.

INTERVENTION

In group 1, 31 patients were treated with either a Neer or Aequalis shoulder prosthesis using nonabsorbable sutures and no bone graft for the reattachment of the tuberosities. In group 2, 27 patients were treated with either an Aequalis or Epoca shoulder prosthesis and a combination of cable fixation and bone grafting.

MAIN OUTCOME MEASUREMENTS

At follow-up (average, 32 months), radiographs were taken to confirm tuberosity fixation or degree of displacement or resorption. Functional outcome was assessed by the Constant-Murley Score.

RESULTS

Significantly more dislocated tuberosities were found radiographically in group 1 (10 of 13 in total, P = 0.011), and significantly more tuberosities were resorbed in group 1 (9 of 12 in total, P = 0.012). Significant differences in functional results among healed versus failed tuberosity fixation were observed for activity of daily living (P = 0.05), range of motion (P = 0.002), strength (P = 0.01), the total score (P = 0.008), and the passive rotation amplitude (P = 0.04).

CONCLUSION

In hemiarthroplasties for proximal humeral fractures, the reattachment of the tuberosities with cable wire and bone grafting gives consistently better radiographic and functional results than with suture fixation alone.

Primary hemiarthroplasty in four-part fractures of the proximal humerus: randomized trial of two different implant systems

The objective of this study was to determine the effect of different prosthetic systems on the functional and radiographic outcomes after shoulder arthroplasty for fractures. This study comprised 35 patients (28 women and 7 men) with a mean age of 74 years (range, 56-88 years) who sustained 4-part fractures of the proximal humerus and were randomly allocated to 2 different groups regarding the type of prosthesis. The 2 systems used differ mainly in the type of fixation of the tuberosities. In group 1 (EPOCA), the fixation was achieved with wire cables through a medial and a lateral hole in the stem, whereas in group 2 (HAS), the fixation was performed by use of transosseous braided sutures. After a follow-up of 1 year, the functional and radiographic outcomes were evaluated. The retrieved data demonstrate that rigid fixation and anatomic positioning of the tuberosities (group 1) increase the rate of bony healing superior to all other factors. There was a statistically significant difference regarding the relative individual Constant score (P = .001) and the mean active range of motion (flexion, P < .001; abduction, P = .001; external rotation in adduction, P = .01; and external rotation in 90 degrees abduction, P = .001) when both groups were compared, showing a better outcome in the EPOCA group for all parameters. Radiologic findings, like heterotopic ossification, glenoid erosion, or subluxation, had no significant influence on the outcome in this study. Accurate placement of the tuberosities and healing at the bone-bone interface of the rotator cuff seem to be the most important factors influencing the outcome in prosthetic care of fractures.

Reconstructing proximal humeral fractures using the bicipital groove as a landmark

Controversy persists in the literature regarding the use of the bicipital groove as an anatomic landmark to restore humeral head retroversion when treating complex proximal humeral fractures with arthroplasty. We quantified the three-dimensional geometry of the bicipital groove in 49 dried humeri relative to the intramedullary axis, quantified the reliability of using the bicipital groove as an anatomic landmark, and compared this reliability with that of the conventional technique that uses a fixed, average angle relative to the epicondylar axis to establish humeral head retroversion. The data show the anterior offset of the bicipital groove is nearly constant from proximal (7.3 mm +/- 2.8 mm) to distal (7.2 mm +/- 1.5 mm) relative to the intramedullary axis. Given the consistency, the distal bicipital groove (at the level of the surgical neck) is a reasonable landmark to establish humeral head retroversion after complex proximal humeral fractures having reliability (angular error of 7.9 degrees +/- 5.8 degrees) as good as or better than the conventional fixed-angle technique.

An anthropometric study of the bilateral anatomy of the humerus

The purpose of this study was to describe the extramedullary humeral morphology in paired humeri to determine whether geometric differences exist from side to side in the same individual. The anatomic characteristics of 28 paired, dry cadaveric humeri were measured by use of an electromagnetic tracking system. Of the characteristics examined, only the humeral head height was significantly different between right and left humeri in the same individual (P < .005). Most of the characteristics had excellent intra-specimen repeatability. In conclusion, there are few significant differences between contralateral humeral anatomic characteristics. Therefore, the uninjured contralateral humerus can provide a reasonable approximation to the native geometry of the fractured humerus and should be a reliable model for measuring parameters related to implant geometry and optimal positioning during hemiarthroplasty for the treatment of proximal humeral fractures.

Bicipital groove orientation: considerations for the retroversion of a prosthesis in fractures of the proximal humerus

The bicipital groove anatomy is well documented, and this groove is used as a landmark to guide retroversion during implantation of a shoulder prosthesis. Whereas the proximal part of the groove is used in osteoarthritis, the distal part is used in fractures. If used in 4-part fracture cases, we must assume that the bicipital groove orientation is constant from proximal to distal. We measured the groove orientation in 40 cadaveric humeri using 3 superimposed computed tomography sections. The reference axis was the transepicondylar axis at the elbow level. The measured angle of the bicipital groove was 55.8 degrees +/- 4.5 degrees at the anatomic neck and 65.1 degrees +/- 3.5 degrees at the surgical neck. This difference (mean of 9.3 degrees, with extremes of -3 degrees and 22.5 degrees) was statistically significant. We confirmed a wide range of variation from 22 degrees to 89 degrees in the orientation of the groove. Because the values listed in the literature for lateral fin placement of a prosthesis have not been measured at the surgical neck level and because of the great variation in groove orientation, we caution surgeons about the use of the bicipital groove as a reliable landmark in shoulder replacement for fractures. Considering the risk of over- or under-retroversion of the prosthesis, we recommend the use of a fracture jig with retroversion set to 20 degrees.

Proximal humerus fractures

Proximal humerus fractures are common injuries. Knowledge of local anatomy is paramount in the evaluation and treatment of these injuries. Information regarding humeral head vascularity, fracture patterns, bone quality, and overall geometry have direct implications for nonoperative treatment, internal fixation, and hemiarthroplasty. The ascending branch of the anterior circumflex artery perfuses most of the humeral head. When fractured, the greater tuberosity tends to displace posterosuperiorly, the lesser tuberosity and the shaft displace medially, and the head may be pulled by the attached tuberosity, impacted into valgus, or in more severe cases dislocated, impacted, or divided. Internal fixation of two-part, three-part, and selected four-part fractures may be compromised by local osteopenia; knowledge of the location of the strongest bone in the proximal humerus combined with the use of fixed-angle devices and occasionally bone graft or substitutes has improved the outcome of osteosynthesis. When the humeral head cannot be preserved, successful hemiarthroplasty requires tuberosity union and anatomic restoration of the overall geometry of the proximal humerus in terms of height, retroversion, and head-tuberosity relationships.

Prognostic factors in prosthetic replacement for acute proximal humerus fractures

OBJECTIVES

To investigate the effect of some epidemiological and radiologic factors on the outcome of prosthetic replacement in acute proximal humerus fractures.

DESIGN

Retrospective clinical study.

PATIENTS

Thirty-two patients [mean age 58 (range 37-83 years)] with a mean follow-up period of 35 months (range 8-80 months). Fifteen cases had Neer type IV, 2 had type III, and 15 patients had fracture-dislocations.

MAIN OUTCOME MEASUREMENTS

Neer's criteria, Constant score, and elevation degree were used. Radiological parameters were union and position of the tuberosities, bone stock, and position of the prosthesis.

RESULTS

Excellent or good results according to Neer's criteria were obtained in 24 of the 32 cases (75%), and unsatisfactory results in 8 cases (25%). Mean Constant score was 68 (range 19-98) and mean elevation degree 113 (range 30-180). Thirty-one cases (97%) had no or mild pain. Cases operated within 14 days following injury had a better general outcome (p = 0.005). The humeral offset was directly correlated to the elevation degree (p = 0.011) and Constant score (p = 0.002), whereas the head height was inversely correlated to the same parameters (p = 0.001 for both). The cutoff point for the humeral offset-general outcome correlation was calculated as 23 mm using ROC curve analysis. The most common complications were problems concerning the tuberosities (50%), and they adversely affected the clinical outcome (p = 0.002).

CONCLUSIONS

Preoperative delay, problems of tuberosity fixation, and position of the tuberosities were parameters influencing the clinical outcome. Lateralization of the tuberosities results in better scores, whereas their distal transfer can be related to a poorer outcome.