Evaluation of articular cartilage thickness of the humeral head and the glenoid fossa by MR arthrography: anatomic correlation in cadavers

Minimal but potentially clinically relevant anteroinferior position of the humeral head following traumatic anterior shoulder dislocations: A 3D-CT analysis

In unstable shoulders, excessive anteroinferior position of the humeral head relative to the glenoid can lead to a dislocation. Measuring humeral head position could therefore be valuable in quantifying shoulder laxity. The aim of this study was to measure (1) position of the humeral head relative to the glenoid and (2) joint space thickness during passive motion in unstable shoulders caused by traumatic anterior dislocations and in contralateral uninjured shoulders. A prospective cross-sectional CT-study was performed in patients with unilateral anterior shoulder instability. Patients underwent CT scanning of both injured and uninjured side in supine position (0° abduction and 0° external rotation) and in 60°, 90°, and 120° of abduction with 90° of external rotation without an external load. Subsequently, 3D virtual models were created of the humerus and the scapula to create a glenoid coordinate system to identify poster-anterior, inferior-superior, and lateral-medial position of the humeral head relative to the glenoid. Joint space thickness was defined as the average distance between the subchondral bone surfaces of the humeral head and glenoid. Fifteen consecutive patients were included. In supine position, the humeral head was positioned more anteriorly (p = 0.004), inferiorly (p = 0.019), and laterally (p = 0.021) in the injured compared to the uninjured shoulder. No differences were observed in any of the other positions. A joint-space thickness map, showing the bone-to-bone distances, identified the Hill-Sachs lesion footprint on the glenoid surface in external rotation and abduction, but no differences on average joint space thickness were observed in any position.

The effects of tears in infraspinatus on other rotator cuff constituents

The rotator cuff tear effects on glenohumeral joint tissues, such as superior labrum anterior-posterior (SLAP) lesions, have been studied experimentally or numerically in various cases. In relation to these studies, and as a novel feature of our study, infraspinatus (INF) muscle tear effects on other muscle force variations and stress and strain increases on glenoid labrum (GL), glenoid cartilage (GC) tissues, and a SLAP pathology were investigated. The ITK-SNAP Software (ISS) was used to segment the humerus and glenoid bone. The surface entities were segmented and exported to SolidWorks 2019, where the finite element model (FEM) was completed. Static optimizations of the muscle forces were calculated using a generic model in OpenSim 4.1 for the 0-3.88 s time interval to perform our finite element analyses (FEAs) in ANSYS 19.3 for the intact, partial torn, and fully torn INF muscle. The FEAs were also conducted for the specified time interval. The stress and strain increases on the GL, and GC tissues were determined to be critical when compared with yield strengths. In the case of fully torn INF, the GL and cartilage interfacial principal stress was calculated to be 3.3856 MPa. In the case of the fully torn INF, the principal stress that occurred on the GC tissue was calculated to be 42.465 MPa. In the case of the intact INF, the principal stress that occurred on the labrum was obtained as 4.257 MPa. These results showed that there was no detachment or disorder on the designated tissues caused by the INF muscle tear when the shoulder functioned at 60° of external rotation at 11° of abduction. Nonetheless, a minor amount of external force could cause severe pathological effects on the specified tissues.

Simultaneous Arthroscopic Rotator Cuff Repair and Glenoid Microfracture in Active-Duty Military Patients Younger Than 50 Years: Outcomes at Midterm Follow-up

Background

While concomitant full-thickness rotator cuff tears and glenoid osteochondral defects are relatively uncommon in younger patients, military patients represent a unique opportunity to study this challenging injury pattern.

Purpose/Hypothesis

To compare the outcomes of young, active-duty military patients who underwent isolated arthroscopic rotator cuff repair (ARCR) with those who underwent ARCR plus concurrent glenoid microfracture (ARCR+Mfx). It was hypothesized that ARCR+Mfx would produce significant improvements in patient-reported outcome measures.

Study Design

Cohort study; Level of evidence, 3.

Methods

This was a retrospective analysis of consecutive active-duty military patients from a single base who underwent ARCR for full-thickness rotator cuff tears between January 2012 and December 2020. All patients were <50 years and had minimum 2-year follow-up data. Patients who underwent ARCR+Mfx were compared with those who underwent isolated ARCR based on the visual analog scale (VAS) for pain, Single Assessment Numeric Evaluation (SANE), American Shoulder and Elbow Surgeons (ASES) shoulder score, and range of motion.

Results

A total of 88 patients met the inclusion criteria for this study: 28 underwent ARCR+Mfx and 60 underwent isolated ARCR. The mean final follow-up was 74.11 ± 33.57 months for the ARCR+Mfx group and 72.87 ± 11.46 months for the ARCR group (P = .80). There were no differences in baseline patient characteristics or preoperative outcome scores between groups. Postoperatively, both groups experienced statistically significant improvements in all outcome scores (P < .0001 for all). However, the ARCR+Mfx group had significantly worse VAS pain (1.89 ± 2.22 vs 1.03 ± 1.70; P = .05), SANE (85.46 ± 12.99 vs 91.93 ± 12.26; P = .03), and ASES (86.25 ± 14.14 vs 92.85 ± 12.57; P = .03) scores. At the final follow-up, 20 (71.43%) patients in the ARCR+Mfx group and 53 (88.33%) patients in the ARCR group were able to remain on unrestricted active-duty military service (P = .05).

Conclusion

Concomitant ARCR+Mfx led to statistically and clinically significant improvements in patient-reported outcome measures at the midterm follow-up. However, patients who underwent ARCR+Mfx had significantly worse outcomes and were less likely to return to active-duty military service than those who underwent isolated ARCR. The study findings suggest that ARCR+Mfx may be a reasonable option for young, active patients who are not candidates for arthroplasty.

Glenohumeral Cartilage Thickness: Implications in Prosthetic Design and Osteochondral Allograft Transplantation

OBJECTIVE

A complete understanding of the glenohumeral joint anatomy is crucial for osteochondral allograft (OCA) transplantation and prosthetic design. However, existing data on the cartilage thickness distribution are not consistent. This study aims to describe the cartilage thickness distribution at both the glenoid cavity and humeral head in males and females.

DESIGN

Sixteen fresh cadaveric shoulder specimens were dissected and separated to expose the glenoid and humeral head articular surfaces. The glenoid and humeral head were cut into 5-mm coronal sections. Sections were imaged and cartilage thickness was measured at 5 standardized points on each section. Measurements were analyzed based on age, sex, and regional location.

RESULTS

For the humeral head, cartilage was thickest centrally (M = 1.77 ± 0.35 mm) and thinnest superiorly and inferiorly (M = 1.42 ± 0.37 mm, 1.42 ± 0.29 mm). At the glenoid cavity, cartilage was thickest in the superior and inferior areas (M = 2.61 ± 0.47 mm, 2.53 ± 0.58 mm) and thinnest centrally (M = 1.69 ± 0.22 mm). Males were found to have thicker cartilage at both the humeral head and glenoid (P = 0.0014, P = 0.0133).

CONCLUSIONS

Articular cartilage thickness distribution of the glenoid and humeral head is nonuniform and reciprocal in nature. These results can be used to further inform prosthetic design and OCA transplantation. We noted a significant difference in cartilage thickness between males and females. This suggests that the sex of the patient should be taken into consideration when matching donors for OCA transplantation.

Influence of Graft Positioning during the Latarjet Procedure on Shoulder Stability and Articular Contact Pressure: Computational Analysis of the Bone Block Effect

The Latarjet procedure is the most popular surgical procedure to treat anterior glenohumeral (GH) instability in the presence of large anterior glenoid bone defects. Even though the placement of the bone graft has a considerable influence on its efficacy, no clear indications exist for the best graft position. The aim of this study was to investigate the influence of the medial-lateral positioning of the bone graft on the contact mechanics and GH stability due to the bone block effect. Four finite element (FE) models of a GH joint, with a 20% glenoid bone defect, treated by the Latarjet procedure were developed. The FE models differed in the medial-lateral positioning of the bone graft, ranging from a flush position to a 4.5 mm lateral position with respect to the flush position. All graft placement options were evaluated for two separate shoulder positions. Anterior GH instability was simulated by translating the humeral head in the anterior direction, under a permanent compressive force, until the peak translation force was reached. Joint stability was computed as the ratio between the shear and the compressive components of the force. The lateralization of the bone graft increased GH stability due to the bone block effect after a 3 mm lateralization with respect to the flush position. The increase in GH stability was associated with a concerning increase in peak contact pressure due to the incongruous contact between the articulating surfaces. The sensitivity of the contact pressures to the medial-lateral positioning of the bone graft suggests a trade-off between GH stability due to the bone block effect and the risk of osteoarthritis, especially considering that an accurate and consistent placement of the bone graft is difficult in vivo.

Biomechanical, Morphological, and Biochemical Characteristics of Articular Cartilage of the Ovine Humeral Head

OBJECTIVE

Shoulder pain is commonly attributed to rotator cuff injury or osteoarthritis. Ovine translational models are used to investigate novel treatments aimed at remedying these conditions to prevent articular cartilage degeneration and subsequent joint degradation. However, topographical properties of articular cartilage in the ovine shoulder are undefined. This study investigates the biomechanical, morphological, and biochemical attributes of healthy ovine humeral head articular cartilage and characterizes topographical variations between surface locations.

DESIGN

Ten humeral heads were collected from healthy skeletally mature sheep and each was segregated into 4 quadrants using 16 regions of interest (ROIs) across the articular surface. Articular cartilage of each ROI was analyzed for creep indentation, thickness, and sulfated glycosaminoglycan (sGAG) and collagen quantity. Comparisons of each variable were made between quadrants and between ROIs within each quadrant.

RESULTS

Percent creep, thickness, and sGAG content, but not collagen content, were significantly different between humeral head quadrants. Subregion analysis of the ROIs within each surface quadrant revealed differences in all measured variables within at least one quadrant. Percent creep was correlated with sGAG (r = -0.32, P = 0.0001). Collagen content was correlated with percent creep (r = 0.32, P = 0.0009), sGAG (r = -0.19, P = 0.049), and thickness (r = -0.19, P = 0.04).

CONCLUSIONS

Topographical variations exist in mechanical, morphologic, and biochemical properties across the articular surface of the ovine humeral head. Recognizing this variability in ovine humeral head cartilage will provide researchers and clinicians with accurate information that could impact study outcomes.

Assessment of Safe Cartilage Harvesting Quantity in the Shoulder: A Cadaveric Study

Purpose

To evaluate the volume and yield of morselized cartilage that can be harvested from the shoulder for immediate reimplantation and repair.

Methods

A standard arthroscopic approach was used to harvest non–load-bearing cartilage from 5 cadaveric shoulder specimens. Cartilage was separated from the humerus, grasped, added to the cartilage particulator, and morselized to form a cartilage paste. The volume of reclaimed cartilage was measured and compared with average humeral and glenoid defects.

Results

The total yield of cartilage paste following tissue processing that was obtained from the 5 glenohumeral joints ranged from 1.0 mL to 2.4 mL with a mean volume of 1.9 ± 0.5 mL, yielding a theoretical 18.6 cm² ± 5.2 cm² of coverage with a 1-mm monolayer. Previously reported mean glenoid defect size ranges from 1.12 cm² to 2.73 cm², while the mean humeral defect size ranges from 4.22 cm² to 6.00 cm².

Conclusions

This study validated that through a single-stage surgical and processing technique it is possible to obtain a sufficient volume for re-implantable autologous morselized cartilage graft to address most glenohumeral articular cartilage defects.

Clinical Relevance

Chondrocyte grafts have been shown to be effective in cartilage repair. A single-site, single-staged procedure that uses a patient’s autologous shoulder cartilage from the same joint has the potential to reduce morbidity associated with multiple surgical sites, multistaged procedures, or nonautologous tissue in shoulder surgery.

Glenohumeral Microfracturing of Contained Glenohumeral Defects: Mid- to Long-term Outcome

Purpose

To report mid- to long-term clinical and radiological outcomes after microfracturing for symptomatic chondral defects of the glenohumeral joint.

Methods

All patients who underwent glenohumeral arthroscopic microfracturing between 2002 and 2012 at a single center were considered for inclusion in this retrospective study. Clinical outcome was evaluated using the Constant Score, Oxford Shoulder Score, and Subjective Shoulder Value. Progression of joint space narrowing, sclerosis, marginal osteophytes, and presence of cysts over time were assessed using 4 different radiological grading systems.

Results

A total of 16 patients (n = 9 female, n = 7 male) with a mean age of 51.8 ± 12.6 years at the time of surgery and a mean follow-up of 122 ± 51.2 months (range, 61-204 months) were included in this retrospective study. Nine patients (56.3%) showed an isolated chondral defect, while 7 patients (43.8%) had concomitant pathologies. Constant Score (60.3 ± 12.7 vs. 85.9 ± 9.3; P < .001), Oxford Shoulder Score (29.0 ± 5.8 vs. 42.4 ± 4.5; P < .001), and Subjective Shoulder Value (23.9 ± 7.4 vs. 84.3 ± 10.9; P < .001) changed significantly from pre- to postoperative. The majority of patients (88%) were able to return to their preoperative level of activity. Three patients (19.8%) developed radiological signs of progressive glenohumeral degeneration during the study period. However, only 1 patient (6.25%) showed a progression of arthritic changes of more than 1 grade according to radiographic classifications. Two patients (12.5%) underwent revision surgery to a hemi shoulder arthroplasty during the study period at 12 and 36 months after the initial procedure.

Conclusions

Glenohumeral microfracturing is commonly performed together with other procedures, but seems to be a feasible treatment option for contained cartilage lesions in active patients reproducibly yielding good mid- to long-term outcome.

Level of Evidence

Level IV, therapeutic case series.

Evaluation of Cartilage in the Wrist using Magnetic Resonance Imaging

Wrist pain is a common patient complaint with a myriad of clinical conditions that can explain the underlying cause. Short of wrist arthroscopy, no technique other than formal wrist arthrotomy exists for direct examination of the hyaline cartilage coating the articular surfaces of the carpal bones. Magnetic resonance imaging (MRI) has been proven accurate in evaluating joint surfaces of large joints such as the shoulder, hip, and knee with articular cartilage surface thickness is in excess of 1 mm. However, in the carpus the thickness of the cartilage and the contours present have precluded accurate imaging. Advances in MRI technology over the last several decades are now making imaging of small joint surfaces, such as the carpus, an area worth revisiting. Herein we provide a review of these efforts with a specific focus on the evaluation of the wrist.

A Biomechanical and Structural Comparison of Articular Cartilage and Subchondral Bone of the Glenoid and Humeral Head

Background:

The underlying cause of glenohumeral arthritis is poorly understood. Glenohumeral arthrosis patterns have been classified and described, and differential contact stresses within the joint have been implicated as a cause of joint degeneration, but the intrinsic cause of degeneration patterns in the glenohumeral joint (GHJ) remains largely unknown.

Purpose/Hypothesis:

The purpose of this study was to assess morphological and mechanical differences in articular cartilage (AC) and subchondral bone (SCB) of the glenoid and humeral head in matched cadaveric specimens. We hypothesized that there would be significant zone-dependent differences between the intrinsic characteristics (AC thickness, SCB thickness, compressive forces) of the glenoid and humeral head.

Study Design:

Descriptive laboratory study.

Methods:

Ten human cadaveric GHJs (mean age, 60.2 years) were dissected to expose articular surfaces to facilitate biomechanical testing. A 2-mm and 6-mm osteochondral plug was harvested at 5 zones (central, anterior, posterior, inferior, superior) on the glenoid and humeral head (N = 200 plugs). Each 2-mm core was histologically sectioned and stained with hematoxylin and eosin. AC thickness measurements were taken using light microscopy. The 6-mm plugs were imaged using micro–computed tomography to measure SCB thickness. After imaging, AC specimens were removed from the SCB and tested in confined compression. The compressive aggregate modulus (H_A0), compressive stiffening coefficient (β), and compressive modulus at 16% strain (H_A0.16) and at 50% strain (H_A0.50) were calculated.

Results:

The overall AC thickness was significantly greater on the glenoid. The glenoid also had significantly thicker AC at the inferior, posterior, and superior zones as well as significantly higher SCB thickness overall and significantly greater SCB thickness at the anterior and central zones. The glenoid had significantly greater overall H_A0.50 and H_A0.50 values at the superior zone and had a significantly greater overall compressive stiffening coefficient (β).

Conclusion:

The glenoid had thicker AC, thicker SCB, and greater compressive stiffness at high strain.

Clinical Relevance:

These intrinsic differences may help better elucidate the cause of differential degeneration patterns between the glenoid and humeral head.

Management of Articular Cartilage Defects in the Glenohumeral Joint

Articular cartilage defects are not often encountered in the glenohumeral joint. These lesions are typically found in patients with shoulder trauma, recurrent instability, or previous surgical treatment. Diagnosis can be difficult; these defects are often found incidentally during arthroscopic or open surgical management of other pathology. Initial management of isolated glenohumeral chondral defects is nonsurgical and includes physical therapy and/or corticosteroid injections. If nonsurgical treatment is unsuccessful, patients may undergo surgery. Because these lesions occur infrequently, few studies have documented surgical techniques and outcomes. Surgical strategies include arthroscopic débridement, microfracture surgery, osteochondral autograft or allograft transplantation, autologous chondrocyte implantation, and particulated juvenile allograft cartilage implantation.

Morphologic Variability of the Shoulder between the Populations of North American and East Asian

Background

The aim of this study was to determine if there were significant differences in glenohumeral joint morphology between North American and East Asian populations that may influence sizing and selection of shoulder arthroplasty systems.

Methods

Computed tomography reconstructions of 92 North American and 58 East Asian patients were used to perform 3-dimensional measurements. The proximal humeral position was normalized in all patients by aligning it with the scapular plane utilizing anatomic landmarks. Measurements were performed on the humerus and scapula and included coronal and axial humeral head radius, humeral neck shaft and articular arc angles, glenoid height and width, and critical shoulder angle. Glenohumeral relationships were also measured and included lateral distance to the greater tuberosity and acromion, abduction lever arm, and acromial index. Parametric and nonparametric statistical analyses were used to compare population metrics.

Results

East Asian glenohumeral measurements were significantly smaller for all linear metrics (p < 0.05), with the exception of acromial length, which was greater than in the North American cohort (p < 0.001). The increase in acromial length affected all measurements involving the acromion including abduction lever arms. No difference was found between the neck shaft and articular angular measurements.

Conclusions

The East Asian population exhibited smaller shoulder morphometrics than their North American cohort, with the exception of an extended acromial overhang. The morphologic data can provide some additional factors to consider when choosing an optimal shoulder implant for the East Asian population, in addition to creating future designs that may better accommodate this population.

T2 mapping of articular cartilage of the glenohumeral joint at 3.0 T in healthy volunteers: a feasibility study

OBJECTIVE

The purpose of this study was to assess the T2 values of the glenohumeral joint cartilage in healthy asymptomatic individuals at 3.0 T and to analyze the T2 profile of the humeral cartilage.

MATERIALS AND METHODS

This prospective study was approved by our institutional review board and written informed consent was obtained. Thirteen subjects (mean age, 28.6 years; age range, 24-33 years) were included and underwent multiecho spin-echo T2-weighted MR imaging and T2 mapping was acquired. Regions of interest were placed on the humeral cartilage and glenoid cartilage on oblique coronal images. T2 profiles of humeral cartilage were measured from the bone-cartilage interface to the articular surface. Intra-observer agreement was analyzed using intraclass correlation coefficient (ICC).

RESULTS

All 13 joints showed normal appearance on conventional T2-weighted images. The mean T2 values of humeral and glenoid cartilage were 50.5 ± 12.1 and 49.0 ± 9.9 ms, respectively. Intra-observer agreement was good, as determined by ICC (0.736). Longer T2 values were observed at the articular surface with a tendency to decrease toward the bone-cartilage interface. The mean cartilage T2 value was 69.03 ± 21.2 ms at the articular surface and 46.99 ± 19.6 ms at the bone-cartilage interface.

CONCLUSION

T2 values of the glenohumeral joint cartilage were similar to reported values of cartilage in the knee. The T2 profile of normal humeral cartilage showed a spatial variation with an increase in T2 values from the subchondral bone to the articular surface.

Quantitative assessment of morphology, T1ρ, and T2 of shoulder cartilage using MRI

OBJECTIVES

The aim of this study was to assess the feasibility of quantifying shoulder cartilage morphology and relaxometry in a clinically feasible scan time comparing different pulse sequences and assessing their reproducibility at 3 Tesla.

METHODS

Three pulse sequences were compared for morphological assessments of shoulder cartilage thickness and volume (SPGR, MERGE, FIESTA), while a combined T1ρ-T2 sequence was optimized for relaxometry measurements. The shoulders of six healthy subjects were scanned twice with repositioning, and the cartilage was segmented and quantified. The degree of agreement between the three morphological sequences was assessed using Bland-Altman plots, while the morphological and relaxometry reproducibility were assessed with root-mean-square coefficients of variation (RMS-CVs) RESULTS: Bland-Altman plots indicated good levels of agreement between the morphological assessments of the three sequences. The reproducibility of morphological assessments yielded RMS-CVs between 4.0 and 17.7 %. All sequences correlated highly (R > 0.9) for morphologic assessments with no statistically significant differences. For relaxometry assessments of humeral cartilage, RMS-CVs of 6.4 and 10.6 % were found for T1ρ and T2, respectively.

CONCLUSIONS

The assessment of both cartilage morphology and relaxometry is feasible in the shoulder with SPGR, humeral head, and T1ρ being the more reproducible morphological sequence, anatomic region, and quantitative sequence, respectively.

KEY POINTS

• The thin cartilage morphology can be assessed in the shoulder in vivo. • Non-invasive biochemical assessment of shoulder cartilage is feasible in vivo using MRI.

Arthroscopic Latarjet procedure: is optimal positioning of the bone block and screws possible? A prospective computed tomography scan analysis

HYPOTHESIS

We hypothesized that the arthroscopic Latarjet procedure could be performed with accurate bone block positioning and screw fixation with a similar rate of complications to the open Latarjet procedure.

METHODS

In this prospective study, 105 shoulders (104 patients) underwent the arthroscopic Latarjet procedure performed by the same senior surgeon. The day after surgery, an independent surgeon examiner performed a multiplanar bidimensional computed tomography scan analysis. We also evaluated our learning curve by comparing 2 chronologic periods (30 procedures performed in each period), separated by an interval during which 45 procedures were performed.

RESULTS

Of the 105 shoulders included in the study, 95 (90.5%) (94 patients) were evaluated. The coracoid graft was accurately positioned relative to the equator of the glenoid surface in 87 of 95 shoulders (91.5%). Accurate bone-block positioning on the axial view with "circle" evaluation was obtained for 77 of 95 shoulders (81%). This procedure was performed in a lateralized position in 7 of 95 shoulders (7.3%) and in a medialized position in 11 shoulders (11.6%). The mean screw angulation with the glenoid surface was 21°. One patient had transient axillary nerve palsy. Of the initial 104 patients, 3 (2.8%) underwent revision. The analysis of our results indicated that the screw-glenoid surface angle significantly predicted the accuracy of the bone-block positioning (P = .001). Our learning curve estimates showed that, compared with our initial period, the average surgical time decreased, and the risk of lateralization showed a statistically significant decrease during the last period (P = .006).

CONCLUSIONS

This study showed that accurate positioning of the bone block onto the anterior aspect of the glenoid is possible, safe, and reproducible with the arthroscopic Latarjet procedure without additional complications compared with open surgery.

Arthroscopic Management of a Glenohumeral Osteochondral Defect Using Particulated Juvenile Cartilage Allograft: A Case Report

CASE

A sixteen-year-old high school varsity quarterback was referred to us for evaluation of right shoulder pain two months after an injury sustained during a football tackle. The patient reported being substantially limited in his ability to perform vigorous activity because of pain and the sensation that his shoulder was about to dislocate. Evaluation showed a Bankart tear and a focal full-thickness glenoid osteochondral defect. The tear was treated with Bankart repair, and the osteochondral defect was filled arthroscopically with particulated juvenile cartilage graft. The patient returned to full sports activity without restriction at nine months after surgery and, at two years of follow-up, remained pain free with full range of motion and strength and no symptoms of instability.

CONCLUSION

The current case suggests that particulated juvenile cartilage may be effective in the treatment of osteochondral lesions of the glenoid.

Automatic bone segmentation and bone-cartilage interface extraction for the shoulder joint from magnetic resonance images

We present a statistical shape model approach for automated segmentation of the proximal humerus and scapula with subsequent bone-cartilage interface (BCI) extraction from 3D magnetic resonance (MR) images of the shoulder region. Manual and automated bone segmentations from shoulder MR examinations from 25 healthy subjects acquired using steady-state free precession sequences were compared with the Dice similarity coefficient (DSC). The mean DSC scores between the manual and automated segmentations of the humerus and scapula bone volumes surrounding the BCI region were 0.926  ±  0.050 and 0.837  ±  0.059, respectively. The mean DSC values obtained for BCI extraction were 0.806  ±  0.133 for the humerus and 0.795  ±  0.117 for the scapula. The current model-based approach successfully provided automated bone segmentation and BCI extraction from MR images of the shoulder. In future work, this framework appears to provide a promising avenue for automated segmentation and quantitative analysis of cartilage in the glenohumeral joint.

Diagnostic performance of CT-arthrography and 1.5T MR-arthrography for the assessment of glenohumeral joint cartilage: a comparative study with arthroscopic correlation

PURPOSE

To compare the diagnostic performance of multi-detector CT arthrography (CTA) and 1.5-T MR arthrography (MRA) in detecting hyaline cartilage lesions of the shoulder, with arthroscopic correlation.

PATIENTS AND METHODS

CTA and MRA prospectively obtained in 56 consecutive patients following the same arthrographic procedure were independently evaluated for glenohumeral cartilage lesions (modified Outerbridge grade ≥2 and grade 4) by two musculoskeletal radiologists. The cartilage surface was divided in 18 anatomical areas. Arthroscopy was taken as the reference standard. Diagnostic performance of CTA and MRA was compared using ROC analysis. Interobserver and intraobserver agreement was determined by κ statistics.

RESULTS

Sensitivity and specificity of CTA varied from 46.4 to 82.4 % and from 89.0 to 95.9 % respectively; sensitivity and specificity of MRA varied from 31.9 to 66.2 % and from 91.1 to 97.5 % respectively. Diagnostic performance of CTA was statistically significantly better than MRA for both readers (all p ≤ 0.04). Interobserver agreement for the evaluation of cartilage lesions was substantial with CTA (κ = 0.63) and moderate with MRA (κ = 0.54). Intraobserver agreement was almost perfect with both CTA (κ = 0.94-0.95) and MRA (κ = 0.83-0.87).

CONCLUSION

The diagnostic performance of CTA and MRA for the detection of glenohumeral cartilage lesions is moderate, although statistically significantly better with CTA.

KEY POINTS

• CTA has moderate diagnostic performance for detecting glenohumeral cartilage substance loss. • MRA has moderate diagnostic performance for detecting glenohumeral cartilage substance loss. • CTA is more accurate than MRA for detecting cartilage substance loss.

Diagnostic accuracy of noncontrast MRI for detection of glenohumeral cartilage lesions: a prospective comparison to arthroscopy

BACKGROUND

The purpose of this study was to determine the prevalence of glenohumeral articular cartilage lesions in patients with rotator cuff tendinopathy and to assess the accuracy of noncontrast magnetic resonance imaging (MRI) in detecting these defects compared with the "gold standard" of arthroscopy.

METHODS

Noncontrast MRI studies obtained in 84 consecutive patients undergoing shoulder arthroscopy for rotator cuff tendinopathy (mean age, 54.8 years; range, 17-82 years) were prospectively evaluated for glenohumeral cartilage lesions. Two fellowship-trained, experienced musculoskeletal radiologists were blinded from the arthroscopic findings and independently evaluated the glenoid and humeral head cartilage on 2 separate occasions.

RESULTS

At arthroscopy, cartilage lesions of the humeral head were detected in 23 patients (frequency, 27.4%), and glenoid cartilage lesions were found in 20 patients (frequency, 23.8%). For detection of a humeral lesion on MRI, the radiologists' combined accuracy was 78%, sensitivity was 43%, and specificity was 91%. The combined accuracy for detection of glenoid lesions on MRI was 84%, sensitivity was 53%, and specificity was 93%. Combining the readers, low-grade lesions (International Cartilage Repair Society grades 1 and 2) of the glenoid and humerus were read as negative on MRI in 63% and 86% of cases, respectively.

CONCLUSION

Overall accuracy of noncontrast MRI for detection of glenohumeral articular cartilage lesions is good; however, interpretation is reader dependent, and accuracy is significantly reduced for detection of low-grade lesions. On the basis of these findings, we recommend that patients with rotator cuff tendinopathy undergoing arthroscopy be informed that the presence and severity of cartilage lesions may be underestimated on MRI.

Kinematic impact of size on the existing glenohumeral joint in patients undergoing reverse shoulder arthroplasty

BACKGROUND

Glenohumeral relationships in reverse shoulder arthroplasty patients have not been previously reported. The purpose of this study was to quantify and compare the shoulder spatial relationships and moment arms. Measurements were used to define general size categories and determine if sizes scale linearly for all metrics.

METHODS

Ninety-two shoulders of patients undergoing primary reverse shoulder arthroplasty for functionally-deficient massive rotator cuff tear without bony deformity or deficiency were evaluated using three-dimensional CT reconstructions and computer-aided design software. Multiple glenohumeral relationships (including moment arm) were measured and evaluated for size stratification and linearity. Generalized linear modeling was used to investigate how predictive glenoid height, coronal humeral head diameter, and gender were of greater tuberosity positions.

FINDINGS

The 92 shoulders were grouped based on glenoid height: small (<33.4mm), medium (33.4-38.0mm), and large (>38.0mm). All relationships varied between groups. The humeral head size, glenoid width, lateral offset, and moment arm all independently increased linearly (r(2)≥0.92) but the rate of increase varied (slope range: 0.59-1.92). Glenoid height, coronal humeral head diameter and gender predicted the greater tuberosity position within mean 1.09mm (standard deviation (SD) 0.84mm) of actual position in 90% of the population.

INTERPRETATION

Distinct groups exist based on the size of the glenoid in shoulder arthroplasty patients. Shoulder modeling should account for size groups, sex, and non-uniform linear scaling of morphometric parameters. Prediction of the greater tuberosity offset can be made using sex and size parameters. Clinical implications include appropriate prosthetic size selection and avoiding large deviations in non-anatomic reconstructions.

MR arthrography of the shoulder: optimizing pulse sequence protocols for the evaluation of cartilage and labrum

OBJECTIVES

To compare axial T1weighted fat-saturated (T1w fs) and T1w non-fs sequences, and coronal T1w-fs and T2w-fs sequences, for evaluation of cartilage and labrum using CT arthrography (CTA) as the reference.

METHODS

Patients had MR arthrography (MRA) and CTA of the shoulder on the same day. Cartilage was assessed for superficial and full thickness focal and diffuse damage. Labral lesions were graded for Bankart variants and SLAP lesions. CTA images were read for the same features. The diagnostic performance of MRA including area under the curve (AUC) was evaluated against CTA.

RESULTS

When comparing axial sequences, the diagnostic performance for cartilage lesion detection on T1w non-fs was 61.9% (sensitivity) 93.6% (specificity) and 89.5% (accuracy) with AUC 0.782, while that for T1w fs was 61.9%, 94.0%, 89.8% and 0.783. For labral assessment, it was 89.1%, 93.0%, 91.4% and 0.919 for T1w non-fs, and 89.9%, 94.0%, 92.6% and 0.922 for T1w fs. Comparing coronal sequences, diagnostic performance for cartilage was 42.5%, 97.5%, 89.8% and 0.702 for T1w fs, and 38.4%, 98.7%, 90.2%, and 0.686 for T2w fs. For the labrum it was 85.1%, 87.5%, 86.2%, and 0.868 for T1w fs, and 75.7%, 97.5%, 80.8% and 0.816 for T2w fs.

CONCLUSIONS

Axial T1w fs and T1w non-fs sequences are comparable in their ability to diagnose cartilage and labral lesions. Coronal T1w fs sequence offers slightly higher sensitivity but slightly lower specificity than T2w fs sequence for diagnosis of cartilage and labral lesions.

Normal curvature of glenoid surface can be restored when performing an inlay osteochondral allograft: an anatomic computed tomographic comparison

PURPOSE

The purpose of this study was to quantitatively measure the morphology of the glenoid and to assess feasibility of using the medial tibial plateau surface as a donor for osteoarticular allograft reconstruction of the glenoid.

METHODS

Using computed tomography (CT), 10 tibias and 10 scapular models from our database (5 males and 5 females in each group) were randomly selected. Commercial software (Mimics, Materialize, Inc., Plymouth, MI) was used to extract the bone contours from the CT images and to reconstruct the 3-dimensional (3D) geometry of the scapula and tibia. By utilizing the software Creo Elements/Pro 5.0 (Parametric Technology Corp., Needham, MA), mean length and width of both the glenoid and medial tibial plateau were calculated. Radius of curvature was then measured in each 3D CT model at three intermediate segment points that were established within the length line at 25, 50, and 75 percent from superior to inferior in the glenoid and from posterior to anterior in the medial tibial plateau. Statistical analysis was performed and determined to be significant for P < 0.05.

RESULTS

The mean (± SD) radius of curvature values at the established 25, 50, and 75 percent segments of the glenoid were 47.4 ± 17.5 mm, 51.2 ± 12.4 mm, and 45.9 ± 17.0 mm, respectively. For the medial tibial plateau, the radius of curvature at 25, 50, and 75 percent were 43.5 ± 9.7 mm, 37.4 ± 14.3 mm and 52.3 ± 21.5 mm, respectively. Values of the glenoid length were 34.0 ± 2.9 mm, and width values were 24.4 ± 2.3 mm. For the medial tibial plateau, the length was 42.6 ± 2.7 mm, and the width was 23.3 ± 4.3 mm. There was no statistical difference in the radius of curvature and dimensional surface area between the glenoid and medial tibial plateau surfaces.

CONCLUSION

The 3D CT-based anatomic study found that there is a statistically similar relationship in the radius of curvature of the glenoid and the medial tibial plateau surface. This concept may allow the medial tibial plateau to be used as a donor for osteoarticular allograft reconstruction of the glenoid, especially in young patients where previous studies have demonstrated that the success rate in shoulder replacements is not as good as in older patients.

Glenohumeral articular cartilage lesions: prospective comparison of non-contrast magnetic resonance imaging and findings at arthroscopy

PURPOSE

The purpose of this study was to assess the diagnostic sensitivity, specificity, accuracy, negative predictive value (NPV), positive predictive value (PPV), and test-retest reliability of magnetic resonance imaging (MRI) for detecting cartilage abnormalities of the glenohumeral joint in comparison with the gold standard of diagnostic arthroscopy.

METHODS

Forty-four patients with a preoperative non-contrast MRI study of their affected shoulder underwent arthroscopy by one surgeon for rotator cuff tendinopathy from 2009 to 2010. Articular cartilage defects were prospectively recorded and graded according to the International Cartilage Repair Society classification system at the time of arthroscopy. One year after surgery, the preoperative MRI were reviewed by a board-certified radiologist and the treating surgeon for articular cartilage defects of both the humeral head and the glenoid. Sensitivity, specificity, accuracy, and test-retest reliability were calculated.

RESULTS

At arthroscopy, 43% of the shoulders were found to have articular cartilage defects. When the readers' findings were combined, the sensitivity of detecting humeral lesions on MRI was 32%; specificity, 80%; accuracy, 63%; PPV, 57%; and NPV, 66%. The sensitivity of detecting glenoid lesions was 31%; specificity, 86%; accuracy, 76%; PPV, 33%; and NPV, 85%.

CONCLUSIONS

This study finds that the overall accuracy of MRI in detecting articular cartilage damage in patients with the clinical diagnosis of subacromial pathology is moderate.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria based on consecutive patients with universally applied reference "gold" standard.

Operative treatment of chondral defects in the glenohumeral joint

PURPOSE

The objectives of this study were to conduct a systematic review of clinical outcomes after cartilage restorative and reparative procedures in the glenohumeral joint, to identify prognostic factors that predict clinical outcomes, to provide treatment recommendations based on the best available evidence, and to highlight literature gaps that require future research.

METHODS

We searched Medline (1948 to week 1 of February 2012) and Embase (1980 to week 5 of 2012) for studies evaluating the results of arthroscopic debridement, microfracture, osteochondral autograft or allograft transplants, and autologous chondrocyte implantation for glenohumeral chondral lesions. Other inclusion criteria included minimum 8 months' follow-up. The Oxford Level of Evidence Guidelines and Grading of Recommendations Assessment, Development and Evaluation (GRADE) recommendations were used to rate the quality of evidence and to make treatment recommendations.

RESULTS

Twelve articles met our inclusion criteria, which resulted in a total of 315 patients. Six articles pertained to arthroscopic debridement (n = 249), 3 to microfracture (n = 47), 2 to osteochondral autograft transplantation (n = 15), and 1 to autologous chondrocyte implantation (n = 5). Whereas most studies reported favorable results, sample heterogeneity and differences in the use of functional and radiographic outcomes precluded a meta-analysis. Several positive and negative prognostic factors were identified. All of the eligible studies were observational, retrospective case series without control groups; the quality of evidence available for the use of the aforementioned procedures is considered "very low" and "any estimate of effect is very uncertain."

CONCLUSIONS

More research is necessary to determine which treatment for chondral pathology in the shoulder provides the best long-term outcomes. We encourage centers to establish the necessary alliances to conduct blinded, randomized clinical trials and prospective, comparative cohort studies necessary to rigorously determine which treatments result in the most optimal outcomes. At this time, high-quality evidence is lacking to make strong recommendations, and decision making in this patient population is performed on a case-by-case basis.

LEVEL OF EVIDENCE

Level IV, systematic review of Level IV studies.

Management of cartilage defects in the shoulder

Articular cartilage lesions of the glenohumeral joint are an especially difficult clinical problem to manage, particularly in the younger, more active patient. Left untreated, these lesions may progress in the long-term, leading to further pain and disability. While shoulder arthroplasty remains a viable option in older patients with glenohumeral arthritis, concerns over component longevity and loosening in younger patients make it less attractive in that age group. Arthroscopic joint debridement with loose body removal, often with capsular release, has been successful in select, more sedentary patients. More recent techniques, including autologous chondrocyte implantation (ACI), osteochondral grafting (allograft versus autograft), interpositional arthroplasty, and microfracture surgery, have been evaluated for use in the shoulder. These procedures have experienced success in weight bearing joints, including the knee and ankle. Despite the good clinical results in the shoulder with short-term follow-up reported in some small series, the treatment of chondral injuries in the glenohumeral joint remains a challenging problem.

Frequency of glenoid chondral lesions on MR arthrography in patients with anterior shoulder instability

PURPOSE

To describe the frequency of glenoid chondral abnormalities in relation to Hill Sachs (HS) lesions in MR arthrograms of patients with anterior shoulder instability versus controls. Such glenoid lesions can directly impact surgical decision-making and approach, and potentially negatively impact outcome if missed.

MATERIALS AND METHODS

Retrospective analysis of direct MR shoulder arthrograms in 165 subjects, (101 with anterior instability/64 controls) was performed independently by 2 blinded musculoskeletal radiologists. Outcome measures were the presence of a HS, anterior labral pathology and glenoid chondral injury. Kappa statistic, Pearson Chi-square and Mann-Whitney analysis were employed for analysis.

RESULTS

Inter-observer variability for the presence of HS, labral and chondral lesions was 0.964, 0.965 and 0.858 respectively, with intra-observer variability of 1.0, 0.985 and 0.861 for the principle reader. 58% of patients and 8% of controls had HS (p<0.001). 72% of patients and 25% of controls had anterior labral injury (p<0.001). 36% of instability patients and 10% controls had glenoid chondral lesions (p<0.001). 46% of anterior instability patients with HS defects had chondral injury as opposed to 21% of patients without HS defects (p=0.009). Depth of the HS lesion did not increase the likelihood of a glenoid chondral lesion (p=0.7335).

CONCLUSION

In the clinical anterior instability cohort, we demonstrated a statistically significant higher number of HS and glenoid chondral lesions than in controls. In anterior instability patients, the presence of a HS lesion confers a statistically significant greater likelihood of having a glenoid chondral lesion when compared to patients with instability and no HS.

Magnetic resonance imaging of shoulder arthropathies

The role of magnetic resonance imaging in evaluating shoulder arthropathies is evolving. This article reviews 4 of the major arthropathies: septic arthritis, rheumatoid arthritis, calcium pyrophosphate dihydrate (CPPD) deposition disease, and hydroxyapatite disease (HAD), with special attention to their magnetic resonance imaging features. Comfort with identifying these entities allows appropriate and prompt treatment, which is critical for joint preservation in the case of infection, for maximal therapeutic efficacy of disease-modifying drugs in the case of rheumatoid arthritis, and for expediting symptomatic relief in the cases of CPPD deposition disease and HAD.

Bone remodelling around a cementless glenoid component

Post-operative change in the mechanical loading of bone may trigger its (mechanically induced) adaptation and hamper the mechanical stability of prostheses. This is especially important in cementless components, where the final fixation is achieved by the bone itself. The aim of this study is, first, to gain insight into the bone remodelling process around a cementless glenoid component, and second, to compare the possible bone adaptation when the implant is assumed to be fully bonded (best case scenario) or completely loose (worst case scenario). 3D finite element models of a scapula with and without a cementless glenoid component were created. 3D geometry of the scapula, material properties, and several physiological loading conditions were acquired from or estimated for a specific cadaver. Update of the bone density after implantation was done according to a node-based bone remodelling scheme. Strain energy density for different loading conditions was evaluated, weighted according to their frequencies in activities of daily life and used as a mechanical stimulus for bone adaptation. The average bone density in the glenoid increased after implantation. However, local bone resorption was significant in some regions next to the bone-implant interface, regardless of the interface condition (bonded or loose). The amount of bone resorption was determined by the condition imposed to the interface, being slightly larger when the interface was loose. An ideal screw, e.g. in which material fatigue was not considered, was enough to keep the interface micromotions small and constant during the entire bone adaptation simulation.

Pictorial essay: pitfalls in magnetic resonance imaging of the shoulder

Numerous imaging pitfalls of normal variants due to imaging technique and artifacts can be seen on routine magnetic resonance imaging of the shoulder. Familiarity with these pitfalls is crucial to avoiding diagnostic errors. Understanding of the common causes of shoulder imaging artifacts will enable the radiologist to make rational changes in imaging technique to eliminate or reduce the effects of artifacts on magnetic resonance images. This pictorial essay highlights possible pitfalls that arise from imaging techniques, imaging artifacts, and normal variations, and how they may be recognized.

The current state of imaging the articular cartilage of the upper extremity

MR imaging has increasingly been used to image joints since its inception. Historically, there has been more emphasis on the evaluation of internal derangement rather than cartilaginous disease. This article reviews cartilaginous diseases of the upper extremity emphasizing those that can be assessed using current clinical MR imaging protocols and addresses the limitations of current imaging techniques in evaluating the articular cartilage of smaller joints. It also provides a brief overview of novel techniques that may be instituted in the future to improve the diagnostic performance of MR imaging in the evaluation of the articular cartilage of the upper extremity.

Efficacy of diagnostic magnetic resonance imaging for articular cartilage lesions of the glenohumeral joint in patients with instability

OBJECTIVE

The purpose of this study was primarily to assess the diagnostic performance of magnetic resonance imaging (MRI) in detecting articular cartilage injuries in patients with glenohumeral instability. A secondary purpose was to assess the diagnostic performance of MRI for detection of Hill-Sachs and Bankart lesions.

MATERIALS AND METHODS

A cohort of 87 consecutive patients who underwent diagnostic MRI and shoulder arthroscopy for instability from 1997 to 2006 were identified. Fifty-five patients (63.2%) underwent MRI with intra-articular contrast medium and 32 patients (36.8%) underwent MRI without contrast medium. MR images were reviewed by two radiologists and interpreted by consensus for the presence of articular cartilage lesions (including Hill-Sachs and Bankart lesions), which were then confirmed by reviewing the operative report and images recorded at arthroscopy.

RESULTS

Mean patient age was 27.0 ± 10.2 years with a mean clinical and radiographic follow-up of 29 (range 3-72) months. Cartilage injuries were detected arthroscopically in 55 patients (63%). Bankart and Hill-Sachs lesions were identified arthroscopically in 66 patients (75.9%) and 55 patients (63.2%) respectively. The overall sensitivity and specificity for detection of glenohumeral articular cartilage lesions by MRI were 87.2% and 80.6% respectively. The sensitivity and specificity of MRI in detecting Bankart lesions was 98.4% (95% CI 91.9, 99.7) and 95.2% (95% CI 77.3, 99.2) respectively. The sensitivity and specificity of MRI in detecting Hill-Sachs lesions was 96.3% (95% CI 87.6, 98.9%) and 90.6% (95% CI 75.7, 96.9) respectively. No statistically significant difference was found between MRI examinations with and without intra-articular gadolinium (p = 0.89).

CONCLUSION

Magnetic resonance imaging demonstrates high sensitivity and specificity for the diagnosis of articular cartilage injuries in patients with glenohumeral instability. MRI with or without intra-articular contrast medium in this study were equally reliable as a non-invasive method for assessment of articular cartilage damage of the glenohumeral joint prior to diagnostic arthroscopy.

Validation of cartilage thickness calculations using indentation analysis

Different methods have been used to cross-validate cartilage thickness measurements from magnetic resonance images (MRIs); however, a majority of these methods rely on interpolated data points, regional mean and/or maximal thickness, or surface mean thickness for data analysis. Furthermore, the accuracy of MRI cartilage thickness measurements from commercially available software packages has not necessarily been validated and may lead to an under- or overestimation of cartilage thickness. The goal of this study was to perform a matching point-to-point validation of indirect cartilage thickness calculations using a magnetic resonance (MR) image data set with direct cartilage thickness measurements using biomechanical indentation testing at the same anatomical locations. Seven bovine distal femoral condyles were prepared and a novel phantom filled with dilute gadolinium solution was rigidly attached to each specimen. High resolution MR images were acquired, and thickness indentation analysis of the cartilage was performed immediately after scanning. Segmentation of the MR data and cartilage thickness calculation was performed using semi-automated software. Registration of MR and indentation data was performed using the fluid filled phantom. The inter- and intra-examiner differences of the measurements were also determined. A total of 105 paired MRI-indentation thickness data points were analyzed, and a significant correlation between them was found (r=0.88, p<0.0001). The mean difference (+/-std. dev.) between measurement techniques was 0.00+/-0.23 mm, with Bland-Altman limits of agreement of 0.45 mm and -0.46 mm. The intra- and inter-examiner measurement differences were 0.03+/-0.22 mm and 0.05+/-0.24 mm, respectively. This study validated cartilage thickness measurements from MR images with thickness measurements from indentation by using a novel phantom to register the image-based and laboratory-based data sets. The accuracy of the measurements was comparable to previous cartilage thickness validation studies in literature. The results of this study will aid in validating a tool for clinical evaluation of in-vivo cartilage thickness.

Articular cartilage and labral lesions of the glenohumeral joint: diagnostic performance of 3D water-excitation true FISP MR arthrography

OBJECTIVE

To evaluate the diagnostic performance of MR arthrography in the detection of articular cartilage and labral lesions of the glenohumeral joint using a transverse 3D water-excitation true fast imaging with steady-state precession (FISP) sequence.

MATERIALS AND METHODS

Seventy-five shoulders were included retrospectively. Shoulder arthroscopy was performed within 6 months of MR arthrography. MR images were evaluated separately by two radiologists. They were blinded to clinical and arthroscopic information. Arthroscopy served as the reference standard.

RESULTS

For the detection of humeral cartilage lesions, sensitivities and specificities were 86% (12/14)/89% (50/56) for observer 1 and 93%/86% for observer 2) for the transverse true FISP sequence and 64%/86% (50%/82% for observer 2) for the coronal intermediate-weighted spin-echo images. The corresponding values for the glenoidal cartilage were 60% (6/10)/88% (51/58) (80%/76% for observer 2) and 70%/86% (60%/74% for observer 2) respectively. For the detection of abnormalities of the anterior labrum (only assessed on true FISP images) the values were 94% (15/16)/84% (36/43) (88%/79% for observer 2). The corresponding values for the posterior labrum were 67% (8/12)/77% (36/47) (observer 2: 25%/74%). The kappa values for the grading of the humeral and glenoidal cartilage lesions were 0.81 and 0.55 for true FISP images compared with 0.49 and 0.43 for intermediate-weighted fast spin-echo images. Kappa values for true FISP evaluation of the anterior and posterior part of the labrum were 0.81 and 0.70.

CONCLUSION

Transverse 3D true FISP MR arthrography images are useful for the difficult diagnosis of glenohumeral cartilage lesions and suitable for detecting labral abnormalities.

Clinical outcomes after microfracture of the glenohumeral joint

BACKGROUND

Microfracture is an effective surgical treatment for isolated, full-thickness cartilage defects with current data focused on applications in the knee. No studies describing clinical outcomes of patients who have undergone microfracture in the shoulder joint have been reported.

HYPOTHESIS

Treatment of glenohumeral joint articular defects using microfracture would demonstrate similar short-term clinical outcomes when compared with other joints.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

From March 2001 to August 2007, 16 patients (17 shoulders) who underwent arthroscopic microfracture of the humeral head and/or glenoid surface were retrospectively reviewed. All patients were examined by an independent, blinded examiner and completed surveys containing the Simple Shoulder Test (SST), American Shoulder and Elbow Score (ASES), and visual analog scale (VAS).

RESULTS

Two patients were lost to follow-up, for a follow-up rate of 88%. Three patients went on to subsequent shoulder surgery and were considered to have failed results. The mean age was 37.0 years (range, 18-55 years) with an average follow-up of 27.8 months (range, 12.1-89.2 months). The average size of humeral and glenoid defects was 5.07 cm(2) (range, 1.0-7.84 cm(2)) and 1.66 cm(2) (range, 0.4-3.75 cm(2)), respectively. There was a statistically significant decrease from 5.6 +/- 1.7 to 1.9 +/- 1.4 (P < .01) in VAS after surgery as well as statistically significant improvements (P < .01) in SST (5.7 +/- 2.1 to 10.3 +/- 1.3) and ASES (44.3 +/- 15.3 to 86.3 +/- 10.5). Twelve (92.3%) patients claimed they would have the procedure again.

CONCLUSION

Microfracture of the glenohumeral joint provides a significant improvement in pain relief and shoulder function in patients with isolated, full-thickness chondral injuries. Longer term studies are required to determine if similar results are maintained over time.

In Vivo Measurement of Glenohumeral Joint Contact Patterns

The objectives of this study were to describe a technique for measuring in-vivo glenohumeral joint contact patterns during dynamic activities and to demonstrate application of this technique. The experimental technique calculated joint contact patterns by combining CT-based 3D bone models with joint motion data that were accurately measured from biplane x-ray images. Joint contact patterns were calculated for the repaired and contralateral shoulders of 20 patients who had undergone rotator cuff repair. Significant differences in joint contact patterns were detected due to abduction angle and shoulder condition (i.e., repaired versus contralateral). Abduction angle had a significant effect on the superior/inferior contact center position, with the average joint contact center of the repaired shoulder 12.1% higher on the glenoid than the contralateral shoulder. This technique provides clinically relevant information by calculating in-vivo joint contact patterns during dynamic conditions and overcomes many limitations associated with conventional techniques for quantifying joint mechanics.

Outcomes of full-thickness articular cartilage injuries of the shoulder treated with microfracture

PURPOSE

The purpose of this study was to determine whether microfracture provides pain relief and improves shoulder function in patients with chondral defects of the glenohumeral joint.

METHODS

Microfracture was performed in glenohumeral joints with full-thickness chondral lesions. Concomitant procedures were performed as indicated. Patients aged 60 years or older and those with complete rotator cuff tears were excluded. We included 31 shoulders in 30 patients in this study. Included were 25 men and 5 women with a mean age of 43 years (range, 19 to 59 years). Of the 31 surgeries, 6 (19%) progressed to another surgery. Subjective data obtained at a minimum of 2 years' follow-up were available in 24 patients (25 shoulders). Patient pain and functional outcomes were measured by use of the American Shoulder and Elbow Surgeons (ASES) score and patient satisfaction. Data were analyzed by use of paired t tests and regression analysis.

RESULTS

The mean follow-up was 47 months (range, 25 to 128 months). The mean pain scores decreased from 3.8 to 1.6 postoperatively (0, no pain; 10, worst pain). The patients' ability to work, activities of daily living, and sports activity significantly improved postoperatively (P < .05). Painless use of the involved arm improved postoperatively (P < .05). The mean ASES score improved by 20 points over the preoperative score (P < .05). Mean satisfaction with surgical outcome was 7.6 of 10. There was no association between age or gender and surgical outcomes. The greatest improvements were seen in patients who had microfracture of isolated lesions of the humerus.

CONCLUSIONS

Failure occurred in 6 of the 31 shoulders (19%). In the remaining patients there was a significant improvement of 20 points (range, -11 to 45 points) in the ASES score compared with preoperatively. In those patients in whom just the humerus was treated, the greatest improvement was seen, with an increase of 32 points (range, 3 to 87 points). There was a negative correlation between the size of the lesion and ASES improvement (r = -0.351, P = .12). Our data showed the greatest improvement for smaller lesions of the humerus with the worst results in patients with bipolar lesions.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Comparison of MR-arthrography and CT-arthrography in hyaline cartilage-thickness measurement in radiographically normal cadaver hips with anatomy as gold standard

OBJECTIVE

To compare magnetic resonance (MR)-arthrography and multidetector-spiral-computed-tomography (MDSCT)-arthrography in cartilage-thickness measurement, in hips without cartilage loss, with coronal anatomic slices as gold standard.

METHOD

Institutional review board permission to study cadavers of individuals who willed their bodies to science was obtained. Two independent observers measured femoral and acetabular cartilage thicknesses of 12 radiographically normal hips (six women, five men; age range, 52-98 years; mean age, 76.5 years), on MDSCT-arthrographic and MR-arthrographic reformations, and on coronal anatomic slices, excluding regions of cartilage loss. Inter- and intraobserver reproducibilities were determined. Analysis of variance (ANOVA) was used to test differences between MR-arthrographic and MDSCT-arthrographic measurement errors compared to anatomy.

RESULTS

By MR-arthrography, cartilage was not measurable at approximately 50% of points on sagittal and transverse sections, compared to 0-6% of the points by MDSCT-arthrography. In the coronal plane, the difference between MDSCT-arthrographic and MR-arthrographic measurement errors was not significant (P=0.93).

CONCLUSION

In the coronal plane, MR-arthrography and MDSCT-arthrography were similarly accurate for measuring hip cartilage thickness.

Radiographic evaluation of the shoulder

Imaging evaluation of shoulder disorders should begin with radiographs. Several radiographic projections have been developed to best show areas affected by particular clinical disorders. This paper reviews the radiographic examinations that are used at our hospital for evaluating arthritis, impingement, trauma and instability. The techniques used to obtain each of these radiographs are briefly described to better understand the resulting images. An organized approach to assessment of these radiographs is delineated including evaluation of the ABCs (alignment, bone density, cartilage spaces and soft tissues). The expected radiographic findings in normal individuals and in patients with common abnormal conditions are reviewed.

In vivo articular cartilage contact at the glenohumeral joint: preliminary report

BACKGROUND

Little is known about normal in vivo mechanics of the glenohumeral joint. Such an understanding would have significant implications for treating disease conditions that disrupt shoulder function. The objective of this study was to determine articular contact locations between the glenoid and humeral articular surfaces in normal subjects during shoulder abduction with neutral, internal, and external rotations. We hypothesized that glenohumeral articular contact is not perfectly centered and is variable in normal subjects tested under physiological loading conditions.

METHODS

Orthogonal fluoroscopic images and magnetic resonance image-based computer models were used to characterize the centroids of articular cartilage contact of the glenohumeral joint at various static, actively stabilized abduction and rotation positions in five healthy shoulders. The shoulder was investigated at 0 degrees , 45 degrees , and 90 degrees abduction with neutral rotation and then at 90 degrees abduction combined with active maximal external rotation and active maximal internal rotation.

RESULTS

For all the investigated positions, the centroid of contact on the glenoid surface for each individual, on average, was more than 5 mm away from the geometric center of the glenoid articular surface. Intersubject variation of the centroid of articular contact on the glenoid surface was observed with each investigated position, and 90 degrees abduction with maximal internal rotation showed the least variability. On the humeral head surface, the centroids of contact were located at the superomedial quarter for all investigated positions, except in two subjects' positions at 0 degrees abduction, neutral rotation.

CONCLUSIONS

The data showed that the in vivo glenohumeral contact locations were variable among subjects, but in all individuals they were not at the center of the glenoid and humeral head surfaces. This confirms that "ball-in-socket" kinematics do not govern normal shoulder function. These insights into glenohumeral articular contact may be relevant to an appreciation of the consequences of pathology such as rotator cuff disease and instability.

Imaging of the shoulder after surgery

Postoperative imaging of the shoulder is challenging. This article reviews the radiologic evaluation following surgery for subacromial impingment, rotator cuff lesions and glenohumeral instability, including the common surgical procedures, the expected postoperative findings and potential complications. A specific emphasis is made on magnetic resonance imaging.

Articular cartilage thickness of the humeral head: an anatomic study

This study determined the thickness of normal humeral head articular cartilage by anatomic cross section using computer-aided image analysis software. Sixteen adult cadaveric humeral heads were analyzed. Our findings reveal that the thickness of humeral articular cartilage is substantially thinner than articular cartilage found in the knee. The cartilage is thickest in the central portion of the head and becomes progressively thinner towards the periphery. Surgical techniques used to treat pathology in the glenohumeral joint, specifically thermal energy or mechanical debridement, may have deleterious effects on the relatively thin humeral articular cartilage.

Nonarthroplasty alternatives for the treatment of glenohumeral arthritis

Although most glenohumeral cartilaginous lesions are incidental findings and well tolerated, a symptomatic cartilage injury in a young, active individual remains a challenge. The diagnosis of this symptomatic lesion is difficult, and is usually only arrived at once other shoulder comorbidities and sources of glenohumeral pain are ruled out. Once diagnosed, a variety of treatment options are available which include palliative, reparative, restorative, and reconstruction techniques. The smallest lesions are amenable to reparative strategies such as marrow-stimulation, stimulating a fibrocartilaginous response. Larger lesions and those that have failed reparative techniques may be candidates for restorative or reconstruction procedures to replace damaged cartilage with hyaline-like tissue. The presence of bipolar injury may require the use of biologic interpositional arthroplasty. This review describes the challenges associated with the diagnosis and management of glenohumeral arthritis, and provides a treatment framework for use in these challenging patients.

Cartilage lesions of the glenohumeral joint: diagnostic effectiveness of multidetector spiral CT arthrography and comparison with arthroscopy

This study assessed the diagnostic effectiveness of multidetector spiral CT arthrography (MDCTa) in detecting hyaline cartilage abnormalities of the shoulder joint, with correlation to arthroscopy. Shoulder MDCTa images prospectively obtained in 22 consecutive patients (mean age, 50 years; age range, 23-74 years; 12 female, 10 male) were evaluated for glenohumeral cartilage lesions. Two musculoskeletal radiologists independently analysed the cartilage surfaces of the humeral head and of the glenoid fossa in nine anatomical surface areas. Observations of MDCTa were compared to arthroscopic findings. The sensitivity and specificity of MDCTa for grade 2 (substance loss <50%) or higher and grade 3 (substance loss >or=50%) or higher cartilage lesions, the Spearman correlation coefficient between arthrographic and arthroscopic grading, and K statistics for assessing Intra and Interobserver reproducibility were determined. At MDCTa, sensitivities and specificities ranged between 80% and 94% for the detection of grade 2 or higher cartilage lesions, and between 88% and 98% for the detection of grade 3 or higher cartilage lesions. Spearman correlation coefficients between MDCTa and arthroscopic grading of articular surfaces ranged between 0.532 and 0.651. Interobserver agreement was moderate for grading all articular surfaces (kappa = 0.457), but substantial to almost perfect for detecting lesions with substance loss (kappa, 0.618-0.876). In conclusion, MDCTa is accurate for the study of cartilage surface in the entire shoulder joint. This technique may beneficially impact patient's management by means of selecting the proper treatment approach.

MR Imaging of the Shoulder after Surgery

This review article describes postoperative MR findings relating to surgery in shoulder impingement syndrome, including rotator cuff lesions, shoulder instability, and arthroplasty. Potentially misleading postoperative findings are emphasized. Because standard MR imaging may not always be the method of choice for post operative imaging, alternative imaging techniques have been included (MR arthrography, CT arthrography, and sonography).