A novel quantitative grading system for implant fixation in revision total knee arthroplasty.

Aims: Obtaining solid implant fixation is crucial in revision total knee arthroplasty (rTKA) to avoid aseptic loosening, a major reason for re-revision. This study aims to validate a novel grading system that quantifies implant fixation across three anatomical zones (epiphysis, metaphysis, diaphysis). Methods: Based on pre-, intra-, and postoperative assessments, the novel grading system allocates a quantitative score (0, 0.5, or 1 point) for the quality of fixation achieved in each anatomical zone. The criteria used by the algorithm to assign the score include the bone quality, the size of the bone defect, and the type of fixation used. A consecutive cohort of 245 patients undergoing rTKA from 2012 to 2018 were evaluated using the current novel scoring system and followed prospectively. In addition, 100 first-time revision cases were assessed radiologically from the original cohort and graded by three observers to evaluate the intra- and inter-rater reliability of the novel radiological grading system. Results: At a mean follow-up of 90 months (64 to 130), only two out of 245 cases failed due to aseptic loosening. Intraoperative grading yielded mean scores of 1.87 (95% confidence interval (CI) 1.82 to 1.92) for the femur and 1.96 (95% CI 1.92 to 2.0) for the tibia. Only 3.7% of femoral and 1.7% of tibial reconstructions fell below the 1.5-point threshold, which included the two cases of aseptic loosening. Interobserver reliability for postoperative radiological grading was 0.97 for the femur and 0.85 for the tibia. Conclusion: A minimum score of 1.5 points for each skeletal segment appears to be a reasonable cut-off to define sufficient fixation in rTKA. There were no revisions for aseptic loosening at mid-term follow-up when this fixation threshold was achieved or exceeded. When assessing first-time revisions, this novel grading system has shown excellent intra- and interobserver reliability.

Tibial bone defect prediction based on preoperative artefact-reduced CT imaging is superior to standard radiograph assessment.

PURPOSE: The purpose of this study was to evaluate the accuracy of preoperative CT-based Anderson Orthopaedic Research Institute (AORI)-grading and to correlate Computed tomography (CT)-based volumetric defect measurements with intraoperative AORI findings. METHODS: 99 patients undergoing revision total knee arthroplasty (rTKA) with preoperative CT-images were identified in an institutional revision registry. CT-image segmentation with 3D-Slicer Software was used to create 3D tibial bone defects which were then graded according to the AORI-classification. The AORI classification categorizes tibial defects into three types: Type I has healthy cortical and cancellous bone near the joint line, Type II involves metaphyseal bone loss affecting one or both condyles, and Type III indicates deficient metaphyseal bone with distal defects and potential damage to the patellar tendon and collateral ligament attachments. These 3D-CT gradings were compared to preoperative X-ray and intraoperative AORI grading. The Friedman test was used to investigate differences between AORI values of each measurement method. Volumetric 3D-bone defect measurements were used to investigate the relationship between AORI classification and volumetric defect size in the three anatomic zones of the tibia. RESULTS: Substantial agreements between preoperative 3D-CT AORI and intraoperative AORI (kappa = 0.663; P < 0.01) and fair agreements between preoperative X-ray AORI and intraoperative AORI grading (kappa = 0.304; P < 0.01) were found. Moderate correlations between volume of remaining bone and intraoperative AORI grading were found in epiphysis (rS = - 0.529; P < 0.001), metaphysis (rS = - 0.557; P < 0.001) and diaphysis (rS = - 0.421; P < 0.001). Small volumetric differences between AORI I vs. AORI II defects and relatively large differences between AORI II and AORI III defects in each zone were detected. CONCLUSION: Tibial bone defect prediction based on preoperative 3D-CT segmentation showed a substantial agreement with intraoperative findings and is superior to standard radiograph assessment. The relatively small difference in defect volume between AORI I, IIa and IIb suggests that updated CT-based classifications might hold benefits for the planning of rTKA. LEVEL OF EVIDENCE: Retrospective Cohort Study; III.

Which Combination is the Best? A Comparison of the Predictive Potential of Serum Biomarker Combinations to Diagnose Periprosthetic Joint Infection.

BACKGROUND: Without a gold-standard test, recent periprosthetic joint infections (PJI) literature has explored the utility of combining serological results, with promising findings. However, previous studies evaluated fewer than 200 patients and often studied only 1 to 2 test combinations. The purpose of this study was to accumulate a large single-institution cohort of revision total joint arthroplasty (rTJA) patients to determine the diagnostic utility of combination serum biomarkers to identify PJI. METHODS: A single institution longitudinal database was assessed to identify all patients who underwent rTJA from 2017 to 2020. There were 1,363 rTJA patients (715 rTKA patients and 648 rTHA patients) including 273 PJI cases (20%) analyzed. The PJI was diagnosed post-rTJA utilizing 2011 Musculoskeletal Infection Society (MSIS) criteria. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), D-dimer, and interleukin 6 (IL-6) were systematically collected for all patients. RESULTS: The rTKA combination markers of CRP + ESR (sensitivity: 78.3%, specificity: 88.8%, positive predictive value (PPV): 70.0%, negative predictive value (NPV): 92.5%), CRP + D-dimer (sensitivity: 60.5%, specificity: 92.6%, PPV: 63.4%, NPV: 91.7%), and CRP + IL-6 (sensitivity: 38.5%, specificity: 100.0%, PPV: 100.0%, NPV: 92.9%) all yielded higher specificity than CRP alone (sensitivity: 94.4%, specificity: 75.0%, PPV: 55.5%, NPV: 97.6%). Similarly, the rTHA combination markers of CRP + ESR (sensitivity: 70.1%, specificity: 88.8%, PPV: 58.1%, NPV: 93.1%), CRP + D-dimer (sensitivity: 57.1%, specificity: 90.1%, PPV: 43.2%, NPV: 94.1%), and CRP + IL-6 (sensitivity: 21.4%, specificity: 98.4%, PPV: 60.0%, NPV: 91.7%) all yielded higher specificity than CRP alone (sensitivity: 84.7%, specificity: 77.5%, PPV: 45.4%, NPV: 95.8%). CONCLUSION: Overall, in diagnosing PJI for both rTKA and rTHA, 2-marker combinations yielded higher specificity, while 3-marker combinations yielded higher sensitivity compared to CRP alone. However, compared to all 2-marker and 3-marker combinations, CRP demonstrated superior overall diagnostic utility. These findings suggest that routine combination testing of markers for PJI diagnosis may be excessive and an unnecessary use of resources, especially in resource-limited situations.

Does Acetabular Bone Loss Severity Associate With Patient-Reported Outcome Measures and Reoperation Rate in Revision Total Hip Arthroplasty?

BACKGROUND: Acetabular bone loss is a challenging clinical problem when performing revision total hip arthroplasty (rTHA). This study aimed to evaluate how acetabular bone loss severity influences (1) clinical outcomes and (2) patient-reported outcome measures (PROMs) in rTHA patients. METHODS: Patients who underwent rTHA with acetabular component revision from January 2016 to February 2022 were included. Treating surgeons determined Paprosky acetabular bone loss classification intraoperatively. Patients were grouped based on numeric classification (PI, PII, or PIII) to categorize severity. Hip disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS, JR.) and Lower Extremity Activity Scale (LEAS) score were collected preoperatively and 1 year postoperatively. There were 197 patients included. Paprosky classification was PI for 47 patients (23.9%), PII for 113 patients (57.4%), and PIII for 37 patients (18.8%). Mean clinical follow-up was 29 months (range, 1 to 69). RESULTS: Reoperation rate was 0% (0 patients), 6.2% (7 patients), and 10.8% (4 patients) for PI, PII and PIII groups respectively (P = .052). Mean preoperative HOOS, JR. and LEAS for PI, PII and PIII groups were significantly different, but 1-year postoperative HOOS, JR. and LEAS did not differ significantly. Rates of HOOS, JR. minimal clinically important difference achievement differed significantly between bone loss groups. CONCLUSION: In this study of rTHA patients, greater acetabular bone loss severity was associated with worse preoperative PROMs and trended toward higher reoperation rate. Postoperative PROMs for bone loss severity groups were statistically similar. Patients who had worse acetabular bone loss were more likely to achieve HOOS, JR. minimal clinically important difference postoperatively. LEVEL OF EVIDENCE: III.

Subsidence of a Single-Taper Femoral Stem in Primary Total Hip Arthroplasty: Characterization, Associated Factors, and Sequelae.

BACKGROUND: We characterized subsidence of an uncemented single-taper femoral stem in primary total hip arthroplasty (THA), determined factors associated with subsidence, and evaluated the impact of subsidence on outcome. METHODS: This retrospective study included 502 primary THAs performed using a single-taper stem in Dorr type-A and type-B femora between 2014 and 2018. Subsidence was measured based on distance from the greater trochanter to stem shoulder on calibrated X-rays. Demographics, case-specific data, and outcomes were collected. Changes in subsidence and variables associated with subsidence were determined. RESULTS: Stem subsidence was 1.5 ± 2.3 mm, 1.6 ± 2.0 mm, 2.0 ± 2.6 mm, 2.3 ± 2.3 mm, 2.6 ± 2.5 mm, and 2.7 ± 3.0 mm at 6 weeks, 3 months, 6 months, 1 year, 2 years, and ≥3 years from THA, respectively. Subsidence across all patients at final mean follow-up of 24 months (range, 1 to 101 months) was 2.2 ± 2.6 mm. Pairwise comparison demonstrated that subsidence occurred predominantly within the first 6 months. Significant subsidence (≥5 mm) occurred in 17.3% and was associated with a body mass index (BMI) ≥25 (P = .04). Dorr type, age, sex, and American Society of Anesthesiologists class were not associated with subsidence. There were 2 patients (0.4%) who underwent a revision that could be attributed to subsidence. There was no association between subsidence and pain, limp, need for ambulatory aid, or analgesic use. CONCLUSION: In primary THAs performed using a single-taper prosthesis, average subsidence was 2.2 mm and significant subsidence occurred in 17.3%. Patient BMI was associated with subsidence. Revision surgery related to subsidence was infrequent (0.4%).

Leg-Length Discrepancy Variability on Standard Anteroposterior Pelvis Radiographs: An Analysis Using Deep Learning Measurements.

BACKGROUND: Leg-length discrepancy (LLD) is a critical factor in component selection and placement for total hip arthroplasty. However, LLD radiographic measurements are subject to variation based on the femoral/pelvic landmarks chosen. This study leveraged deep learning (DL) to automate LLD measurements on pelvis radiographs and compared LLD based on several anatomically distinct landmarks. METHODS: Patients who had baseline anteroposterior pelvis radiographs from the Osteoarthritis Initiative were included. A DL algorithm was created to identify LLD-relevant landmarks (ie, teardrop (TD), obturator foramen, ischial tuberosity, greater and lesser trochanters) and measure LLD accurately using six landmark combinations. The algorithm was then applied to automate LLD measurements in the entire cohort of patients. Interclass correlation coefficients (ICC) were calculated to assess agreement between different LLD methods. RESULTS: The DL algorithm measurements were first validated in an independent cohort for all six LLD methods (ICC = 0.73-0.98). Images from 3,689 patients (22,134 LLD measurements) were measured in 133 minutes. When using the TD and lesser trochanter landmarks as the standard LLD method, only measuring LLD using the TD and greater trochanter conferred acceptable agreement (ICC = 0.72). When comparing all six LLD methods for agreement, no combination had an ICC>0.90. Only two (13%) combinations had an ICC>0.75 and eight (53%) combinations had a poor ICC (<0.50). CONCLUSION: We leveraged DL to automate LLD measurements in a large patient cohort and found considerable variation in LLD based on the pelvic/femoral landmark selection. This emphasizes the need for the standardization of landmarks for both research and surgical planning.

Hardware complications and reoperations following precontoured plate fixation of the olecranon: a population-based study.

BACKGROUND: Several fixation techniques have been described to treat acute olecranon fractures. Plate fixation is often used because of its superior mechanical properties. The reported rates of reoperation after olecranon plate fixation have been quite heterogeneous. The purpose of this study was to establish an updated reoperation rate based on modern precontoured plate constructs. METHODS: This retrospective cohort study used population-level administrative data to identify all surgically treated adult patients with olecranon fractures at 4 hospitals in Edmonton, AB, Canada, between 2010 and 2015. Radiographic review was conducted to identify patients who underwent precontoured olecranon plate fixation. Fracture characteristics including Mayo fracture classification and other concomitant upper-extremity injuries were identified. Chart reviews were performed to determine patient characteristics and patients who required reoperation. The primary reason for and type of reoperation were determined. RESULTS: Six hundred patients were surgically treated for olecranon fractures. Precontoured plate fixation was used in 321 patients. The average age of included patients was 56 years (standard deviation [SD], 19.4 years), and there were 173 female patients (53.9%). Reoperation was required in 90 patients (28%). For 50 patients, implant-related irritation was the primary reason for reoperation, representing 55.6% of the patients who underwent reoperation (50 of 90) and 15.6% of the total cohort (50 of 321). Other reasons for reoperation included hardware failure in 17 patients (5.3%), infection in 9 (2.8%), and contracture in 9 (2.8%). Patients who required reoperation were significantly younger (52.9 years [SD, 18.1 years] vs. 57.7 years [SD, 19.4 years]; P = .048) and had significantly higher rates of type III olecranon fractures (17.8% [16 of 90] vs. 8.2% [19 of 231]; P = .04) and Monteggia fractures (13.3% [12 of 90] vs. 4.8% [11 of 231]; P = .008). A multivariate logistic regression model also demonstrated increased odds ratios (ORs) for overall reoperation in patients with Monteggia fractures (OR, 2.99 [95% confidence interval, 1.25-7.17]; P = .014) and for reoperation due to implant-related irritation in younger patients (OR, 0.98 [95% confidence interval, 0.96-0.996]; P = .018). No discerning factors were identified for the 50 patients who underwent hardware removal for implant-related irritation compared with the whole reoperation group (n = 90). CONCLUSION: This study found that patients with olecranon fractures treated with precontoured plates experienced a hardware removal rate of 15.6% for implant-related irritation. Patients who sustained more complex fractures, such as Monteggia injuries, demonstrated higher rates of reoperation. Increasing age may be associated with lower rates of reoperation. In patients who required reoperation, there were no identifiable radiographic or clinical characteristics that were associated with implant-related irritation as their primary reason for reoperation.

Relative Sagittal Alignment of the Medial and Lateral Articular Surfaces of the Tibial Plateau Using Radiographic Parameters: A Radiographic Cadaveric Study.

OBJECTIVES: To characterize anatomic slope (sagittal alignment) of medial and lateral articular surfaces of the tibial plateau using x-ray and computed tomography (CT). METHODS: Fluoroscopy was used to acquire "perfect" anteroposterior (AP) images of 8 cadaveric knees by tilting a C-arm through a 30-degree cranial/caudal arc in 0.5-degree increments. Five surgeons independently selected perfect AP images that most accurately profiled medial and lateral articular surfaces. Corresponding angles were used to define tangent subchondral structures on sagittal CT that were considered as dominant bony landmarks in a protocol to determine tibial slope on sagittal CT in 46 additional cadaveric knees. RESULTS: Mean perfect C-arm AP angles were 4.2 degrees ± 2.6 degrees posterior for the medial plateau and 5.0 degrees ± 3.8 degrees posterior for the lateral plateau. It was noted that images acquired within a range of angles (medial range, 1.8 degrees ± 0.7 degrees; lateral range, 3.9 degrees ± 3.8 degrees) rather than a single angle adequately profiled each compartment. Using the CT protocol, mean medial slope (5.2 degrees ± 2.3 degrees posterior; range, 0.9-11.5 degrees) was less than lateral slope (7.5 degrees ± 3.0 degrees posterior; range 0.6-12.5 degrees; P < 0.001) in 54 knees. The difference between medial and lateral slopes in any individual specimen ranged from 3.1 degree more medially to 6.8 degrees more laterally. No differences were noted between right and left knees in paired specimens. CONCLUSIONS: On average, tibial slope in the lateral plateau is slightly greater than that in the medial plateau, and variation exists between compartments across patients. Because tibial slope is similar between contralateral limbs, evaluating slope on the uninjured side can provide a template for sagittal plane reduction of tibial plateau fractures.

Surgical Technique: Abductor Reconstruction With Gluteus Maximus and Tensor Fascia Lata in Revision Total Hip Arthroplasty.

BACKGROUND: Abductor deficiency in revision total hip arthroplasty (THA) is a common problem that can lead to pain, limping, and instability. Repair and reconstruction of the abductors is challenging, with a high rate of failure reported in the literature. The purpose of this study is to describe a simplified technique of abductor repair augmented with the transfer of gluteus maximus (Gmax) and the tensor fascia lata (TFL). METHODS: We describe a novel abductor reconstruction with transfer of the anterior 30% of Gmax and the posterior 70% of TFL to the vastus lateralis origin. These transfers can be used in isolation or to augment repair of torn abductors to the greater trochanter. The technique is simple and quick to perform via a lateral approach, requiring dissection of only two muscle slips and minimal additional soft tissue dissection. RESULTS: We describe the use and outcomes of this technique on three patients undergoing revision THA with severe and irreparable abductor deficiency. Although these patients reported improved function after the reconstruction, there was persistence of mild to moderate limping. CONCLUSION: Abductor reconstruction with partial transfers of Gmax and TFL is a promising approach to manage abductor deficiency in revision THA. Larger series are required to determine the efficacy of this technique for restoring abductor function and improving patient reported outcomes.

Proximal tibia fracture dislocations: Management and outcomes of a severe and under-recognized injury.

INTRODUCTION: Proximal tibia fracture dislocations (PTFDs) are a subset of plateau fractures with little in the literature since description by Hohl (1967) and classification by Moore (1981). We sought to evaluate reliability in diagnosis of fracture-dislocations by traumatologists and to compare their outcomes with bicondylar tibial plateau fractures (BTPFs). METHODS: This was a retrospective cohort study at 14 level 1 trauma centers throughout North America. In all, 4771 proximal tibia fractures were reviewed by all sites and 278 possible PTFDs were identified using the Moore classification. These were reviewed by an adjudication board of three traumatologists to obtain consensus. Outcomes included inter-rater reliability of PTFD diagnosis, wound complications, malunion, range of motion (ROM), and knee pain limiting function. These were compared to BTPF data from a previous study. RESULTS: Of 278 submitted cases, 187 were deemed PTFDs representing 4% of all proximal tibia fractures reviewed and 67% of those submitted. Inter-rater agreement by the adjudication board was good (83%). Sixty-one PTFDs (33%) were unicondylar. Eleven (6%) had ligamentous repair and 72 (39%) had meniscal repair. Two required vascular repair. Infection was more common among PTFDs than BTPFs (14% vs 9%, p = 0.038). Malunion occurred in 25% of PTFDs. ROM was worse among PTFDs, although likely not clinically significant. Knee pain limited function at final follow-up in 24% of both cohorts. CONCLUSIONS: PTFDs represent 4% of proximal tibia fractures. They are often unicondylar and may go unrecognized. Malunion is common, and PTFD outcomes may be worse than bicondylar fractures.

Surgical outcomes of dual-plate fixation for periprosthetic femur fractures around a stable hip arthroplasty stem.

INTRODUCTION: The incidence of periprosthetic femur fractures is increasing. Multiple treatment methods exist to treat fractures surrounding stable hip arthroplasty implants including locking plate fixation, cable fixation, allograft augmentation, and revision arthroplasty. No consensus regarding optimal treatment has been reached, and significant complications remain. Recently, biomechanical studies have demonstrated the benefits of orthogonal dual-plate fixation, but little clinical data exist. The purpose of the current study was to investigate the clinical and radiographic outcomes of dual-plated periprosthetic femur fractures around stable hip stems. MATERIALS AND METHODS: Patients with periprosthetic femur fractures following hip arthroplasty with a stable femoral stem treated with dual-plate fixation were identified through chart review at a single institution. Fracture classification, fixation characteristics, radiographic outcomes, clinical outcomes and complications including re-operation were recorded. RESULTS: Over a 12-year period, 31 patients (mean age 77 years at surgery, range 48-94) underwent dual plating by three traumatologists for implant-stable periprosthetic femur fractures surrounding a hip arthroplasty stem. There were 27 Vancouver B1-type and 9 inter-prosthetic fractures. Average follow-up was 2 years. Of the 26 patients with minimum 6-month follow-up, 24 (92%) united after index surgery (mean time to union 6.0 months, range 1.5-14.0). Mean time to full weight-bearing post-operatively was 2.6 months (range 1.5-4.0 months). Two patients required secondary surgery to address nonunion. CONCLUSIONS: Dual-plating achieved high union rates with an acceptable complication profile for the treatment of periprosthetic femur fractures surrounding a stable hip arthroplasty stem. Our preferred fixation construct involves a lateral plate spanning the entire femur secured with non-locking bicortical screws supplemented with an anteriorly based reconstruction plate. Additional prospective research is required to confirm the results of this study.

The effect of calcar femoral neck plating on vascularity of the femoral head and neck.

AIMS: Surgical treatment of young femoral neck fractures often requires an open approach to achieve an anatomical reduction. The application of a calcar plate has recently been described to aid in femoral neck fracture reduction and to augment fixation. However, application of a plate may potentially compromise the regional vascularity of the femoral head and neck. The purpose of this study was to investigate the effect of calcar femoral neck plating on the vascularity of the femoral head and neck. METHODS: A Hueter approach and capsulotomy were performed bilaterally in six cadaveric hips. In the experimental group, a one-third tubular plate was secured to the inferomedial femoral neck at 6:00 on the clockface. The contralateral hip served as a control with surgical approach and capsulotomy without fixation. Pre- and post-contrast MRI was then performed to quantify signal intensity in the femoral head and neck. Qualitative assessment of the terminal arterial branches to the femoral head, specifically the inferior retinacular artery (IRA), was also performed. RESULTS: Quantitative MRI revealed a mean reduction of 1.8% (SD 3.1%) of arterial contribution in the femoral head and a mean reduction of 7.1% (SD 10.6%) in the femoral neck in the plating group compared to non-plated controls. Based on femoral head quadrant analysis, the largest mean decrease in arterial contribution was in the inferomedial quadrant (4.0%, SD 6.6%). No significant differences were found between control and experimental hips for any femoral neck or femoral head regions. The inferior retinaculum of Weitbrecht (containing the IRA) was directly visualized in six of 12 specimens. Qualitative MRI assessment confirmed IRA integrity in all specimens. CONCLUSION: Calcar femoral neck plating at the 6:00 position on the clockface resulted in minimal decrease in femoral head and neck vascularity, and therefore it may be considered as an adjunct to laterally-based fixation for reduction and fixation of femoral neck fractures, especially in younger patients. Cite this article: Bone Jt Open 2021;2(8):611-617.

Open Reduction and Internal Fixation of Patella Fracture With Contoured Dorsal Plating.

SUMMARY: In this article, we present a novel patella fixation technique using a low-profile highly contoured dorsal mini-fragment locking plate. This procedure is ideally indicated in patients with fracture patterns that are transverse without significant comminution. Long-term clinical studies are being performed to evaluate the effectiveness of this surgical technique.

Analysis of a generic talar prosthetic with a biological talus: A cadaver study.

Treatment for talar avascular necrosis is challenging. This study evaluates the feasibility of a generic talar implant by cadaveric assessment. Ten cadaveric ankles were CT-scanned to determine talar implant size. The opposite ankles were CT-scanned with the biological talus and then with the implant. 3D ankle geometry was reconstructed and implant position was compared to the biological talus position. The averages among specimens' positive and negative average-deviations were 0.91 mm and 0.70 mm. Seventy percent of talar dome deviations between the biological talus and implant were within an acceptable range. This study yields promising results to support a generic talus bone prosthetic.

Articular Cartilage Repair with Mesenchymal Stem Cells After Chondrogenic Priming: A Pilot Study.

Bone marrow-derived mesenchymal stromal stem cells (BMSCs) are a promising cell source for treating articular cartilage defects. The objective of this study was to assess a protocol that involved autologous transplantation of BMSCs into full-thickness cartilage defects in sheep following isolation, expansion, and a short period (4 days) of chondrogenic priming. The impact of oxygen tension during preimplantation culture was investigated. It was hypothesized that chondrogenically primed BMSCs would produce superior cartilaginous repair tissue relative to control defects, and that culture under hypoxia would yield improved repair tissue in comparison to normoxia. Ovine BMSCs were isolated, expanded to passage 2, seeded within a hyaluronic acid (HYAFF) scaffold, and primed ex vivo in chondrogenic medium for 4 days under normoxia (21% oxygen) or hypoxia (3% oxygen). Full-thickness, 7-mm-diameter articular cartilage defects were created in the femoral condyles of five sheep. Twenty defects were treated with normoxia-cultured, autologous BMSC-seeded scaffolds (eight); hypoxia-cultured, autologous BMSC-seeded scaffolds (eight); cell-free scaffolds (two); or no implants (two). Preimplantation priming was evaluated through gene expression analysis using reverse transcription quantitative polymerase chain reaction. After 6 months, histological assessment was performed on repair tissues with a modified O'Driscoll scoring system and tissue dimension analysis. Priming of preimplantation BMSC-seeded scaffolds in chondrogenic medium for 4 days resulted in significantly increased gene expression of hyaline cartilage-related collagen II and aggrecan relative to unprimed BMSCs (p < 0.05). Defects implanted with chondrogenically primed BMSC-seeded scaffolds developed cartilaginous repair tissues that contained safranin O-positive proteoglycans, and had significantly larger repair tissue areas, higher percentages of defect fill, and improved histological scores than cell-free controls (p < 0.05). Although hypoxic culture improved the preimplantation gene expression profile, a consistent difference in histological scores was not found between normoxia- and hypoxia-seeded BMSC-seeded scaffolds after 6 months (p = 0.90). This study demonstrates in a sheep model that (1) chondrogenic priming ex vivo improves the gene expression profile of BMSCs; (2) chondrogenically primed BMSCs are associated with the development of superior cartilaginous tissue to cell-free controls within cartilage defects; and (3) oxygen tension during preimplantation ex vivo culture does not consistently modulate cartilaginous repair tissue formation following BMSC transplantation into cartilage defects.

Radiographic sclerotic contour loss in the identification of glenoid bone loss.

PURPOSE: Quantification of glenoid bone loss guides surgical management in the setting of anterior shoulder instability. Glenoid defects resulting in ≥20 % articular area loss require bony reconstruction. The objective of this study was to evaluate the utility of sclerotic glenoid contour loss on true anteroposterior radiography in the detection of varying quantities of simulated glenoid bone loss using a cadaveric model. METHODS: Eight cadaveric scapulae with full radiographic sclerotic contour were osteotomized to produce glenoid surface area reductions of 10-50 %. Radiography was performed initially and following each osteotomy, and assessed by an orthopedic surgeon and radiologist twice. Quantity of glenoid loss was compared using Fisher's exact test. Sensitivity, specificity, and reliability analyses were performed. RESULTS: On the first radiographic review, sclerotic contour loss was detected in 6 out of 8 scapulae with 50 % area loss, but only 1 out of 8 scapulae with 20 % area loss. There was a significantly higher proportion of radiographs containing sclerotic contour loss for defects with 50 % area loss compared to those with 0-25 % loss (p ≤ 0.02). In the detection of ≥20 % area loss, sclerotic contour loss had a sensitivity of 33-43 % and specificity of 88-100 %. Moderate inter-observer reliability (Cohen's kappa value of 0.42-0.53) and intra-observer reliability (kappa value of 0.46-0.58) were found. CONCLUSION: Radiographic sclerotic contour loss is commonly observed in radiographs of scapulae with 40-50 % glenoid area loss and less often with smaller lesions. However, this finding lacks utility in discerning specific quantifications of glenoid bone loss. In a clinical setting, sclerotic contour loss suggests the presence of a large glenoid defect that may require bony reconstruction. However, an intact sclerotic contour does not rule out significant bone loss.

Optimal Seeding Densities for In Vitro Chondrogenesis of Two- and Three-Dimensional-Isolated and -Expanded Bone Marrow-Derived Mesenchymal Stromal Stem Cells Within a Porous Collagen Scaffold.

Bone marrow-derived mesenchymal stromal stem cells (BMSCs) are a promising cell source for treating articular cartilage defects. The objective of this study was to assess the impact of cell seeding density within a collagen I scaffold on in vitro BMSC chondrogenesis following isolation and expansion in two-dimensional (2D) and three-dimensional (3D) environments. It was hypothesized that both expansion protocols would produce BMSCs capable of hyaline-like chondrogenesis with an optimal seeding density of 10 × 10(6) cells/cm(3). Ovine BMSCs were isolated in a 2D environment by plastic adherence, expanded to passage two in flasks containing an expansion medium, and seeded within collagen I scaffolds at densities of 50, 10, 5, 1, and 0.5 × 10(6) BMSCs/cm(3). For 3D isolation and expansion, aspirates containing known quantities of mononucleated cells (bone marrow-derived mononucleated cells [BMNCs]) were seeded on scaffolds at 50, 10, 5, 1, and 0.5 × 10(6) BMNCs/cm(3) and cultured in the expansion medium for an equivalent duration to 2D expansion. Constructs were differentiated in vitro in the chondrogenic medium for 21 days and assessed with reverse-transcription quantitative polymerase chain reaction, safranin O staining, histological scoring using the Bern Score, collagen immunofluorescence, and glycosaminoglycan (GAG) quantification. Two-dimensional-expanded BMSCs seeded at all densities were capable of proteoglycan production and displayed increased expressions of aggrecan and collagen II messenger RNA (mRNA) relative to predifferentiation controls. Collagen II deposition was apparent in scaffolds seeded at 0.5-10 × 10(6) BMSCs/cm(3). Chondrogenesis of 2D-expanded BMSCs was most pronounced in scaffolds seeded at 5-10 × 10(6) BMSCs/cm(3) based on aggrecan and collagen II mRNA, safranin O staining, Bern Score, total GAG, and GAG/deoxyribonucleic acid (DNA). For 3D-expanded BMSC-seeded scaffolds, increased aggrecan and collagen II mRNA expressions relative to controls were noted with all densities. Proteoglycan deposition was present in scaffolds seeded at 0.5-50 × 10(6) BMNCs/cm(3), while collagen II deposition occurred in scaffolds seeded at 10-50 × 10(6) BMNCs/cm(3). The highest levels of aggrecan and collagen II mRNA, Bern Score, total GAG, and GAG/DNA occurred with seeding at 50 × 10(6) BMNCs/cm(3). Within a collagen I scaffold, 2D- and 3D-expanded BMSCs are capable of hyaline-like chondrogenesis with optimal cell seeding densities of 5-10 × 10(6) BMSCs/cm(3) and 50 × 10(6) BMNCs/cm(3), respectively.

Imaging methods for quantifying glenoid and Hill-Sachs bone loss in traumatic instability of the shoulder: a scoping review.

BACKGROUND: Glenohumeral instability is a common problem following traumatic anterior shoulder dislocation. Two major risk factors of recurrent instability are glenoid and Hill-Sachs bone loss. Higher failure rates of arthroscopic Bankart repairs are associated with larger degrees of bone loss; therefore it is important to accurately and reliably quantify glenohumeral bone loss pre-operatively. This may be done with radiography, CT, or MRI; however no gold standard modality or method has been determined. A scoping review of the literature was performed to identify imaging methods for quantifying glenohumeral bone loss. METHODS: The scoping review was systematic in approach using a comprehensive search strategy and standardized study selection and evaluation. MEDLINE, EMBASE, Scopus, and Web of Science were searched. Initial selection included articles from January 2000 until July 2013, and was based on the review of titles and abstracts. Articles were carried forward if either reviewer thought that the study was appropriate. Final study selection was based on full text review based on pre-specified criteria. Consensus was reached for final article inclusion through discussion amongst the investigators. One reviewer extracted data while a second reviewer independently assessed data extraction for discrepancies. RESULTS: Forty-one studies evaluating glenoid and/or Hill-Sachs bone loss were included: 32 studies evaluated glenoid bone loss while 11 studies evaluated humeral head bone loss. Radiography was useful as a screening tool but not to quantify glenoid bone loss. CT was most accurate but necessitates radiation exposure. The Pico Method and Glenoid Index method were the most accurate and reliable methods for quantifying glenoid bone loss, particularly when using three-dimensional CT (3DCT). Radiography and CT have been used to quantify Hill-Sachs bone loss, but have not been studied as extensively as glenoid bone loss. CONCLUSIONS: Radiography can be used for screening patients for significant glenoid bone loss. CT imaging, using the Glenoid Index or Pico Method, has good evidence for accurate quantification of glenoid bone loss. There is limited evidence to guide imaging of Hill-Sachs bone loss. As a consensus has not been reached, further study will help to clarify the best imaging modality and method for quantifying glenohumeral bone loss.

Hypoxic culture of bone marrow-derived mesenchymal stromal stem cells differentially enhances in vitro chondrogenesis within cell-seeded collagen and hyaluronic acid porous scaffolds.

INTRODUCTION: The quality of cartilaginous tissue derived from bone marrow mesenchymal stromal stem cell (BMSC) transplantation has been correlated with clinical outcome. Therefore, culture conditions capable of modulating tissue phenotype, such as oxygen tension and scaffold composition, are under investigation. The objective of this study was to assess the effect of hypoxia on in vitro BMSC chondrogenesis within clinically approved porous scaffolds composed of collagen and hyaluronic acid (HA). It was hypothesized that hypoxic isolation/expansion and differentiation would improve BMSC chondrogenesis in each construct. METHODS: Ovine BMSCs were isolated and expanded to passage 2 under hypoxia (3% oxygen) or normoxia (21% oxygen). Cell proliferation and colony-forming characteristics were assessed. BMSCs were seeded at 10 million cells per cubic centimeter on cylindrical scaffolds composed of either collagen I sponge or esterified HA non-woven mesh. Chondrogenic differentiation was performed in a defined medium under hypoxia or normoxia for 14 days. Cultured constructs were assessed for gene expression, proteoglycan staining, glycosaminoglycan (GAG) quantity, and diameter change. RESULTS: Isolation/expansion under hypoxia resulted in faster BMSC population doublings per day (P <0.05), whereas cell and colony counts were not significantly different (P = 0.60 and 0.30, respectively). Collagen and HA scaffolds seeded with BMSCs that were isolated, expanded, and differentiated under hypoxia exhibited superior aggrecan and collagen II mRNA expressions (P <0.05), GAG quantity (P <0.05), and proteoglycan staining in comparison with normoxia. GAG/DNA was augmented with hypoxic isolation/expansion in all constructs (P <0.01). Comparison by scaffold composition indicated increased mRNA expressions of hyaline cartilage-associated collagen II, aggrecan, and SOX9 in collagen scaffolds, although expression of collagen X, which is related to hypertrophic cartilage, was also elevated (P <0.05). Proteoglycan deposition was not significantly improved in collagen scaffolds unless culture involved normoxic isolation/expansion followed by hypoxic differentiation. During chondrogenesis, collagen-based constructs progressively contracted to 60.1% ± 8.9% of the initial diameter after 14 days, whereas HA-based construct size was maintained (109.7% ± 4.2%). CONCLUSIONS: Hypoxic isolation/expansion and differentiation enhance in vitro BMSC chondrogenesis within porous scaffolds. Although both collagen I and HA scaffolds support the creation of hyaline-like cartilaginous tissue, variations in gene expression, extracellular matrix formation, and construct size occur during chondrogenesis.

Porous Scaffold Seeding and Chondrogenic Differentiation of BMSC-seeded Scaffolds.

Bone marrow-derived mesenchymal stromal stem cells (BMSCs) are a promising cell source for treating articular cartilage defects (Bornes et al., 2014). BMSCs can be seeded within porous biomaterial scaffolds that support three-dimensional cell organization, chondrogenic differentiation and extracellular matrix deposition for the creation of engineered cartilage. This protocol describes our defined methods for isolation and expansion of human and ovine BMSCs, seeding of BMSCs within porous scaffolds and in vitro chondrogenic differentiation (Adesida et al., 2012; Bornes et al., 2015).