Percentage Of Bone Loss Research Articles

Influence sur l’activité quotidienne d’une perte de substance glénoïdienne modérée dans l’instabilité antérieure d’épaule

BackgroundIt has been biomechanically demonstrated that 20 to 25% is a critical glenoid bone loss. Recently, there are several reports describing that a bone loss less than 20 to 25% needed to be treated because patients may have decreased quality of life without recurrent instability events. The purpose of this study was to clarify the presence of subcritical bone loss that would affect postoperative instability or quality of life. MethodsSubjects were 43 patients aged≤40 years with less than 25% glenoid bone loss who had undergone arthroscopic Bankart repair. These patients were assessed at a mean follow-up of 32 months. The Western Ontario Shoulder Instability (WOSI) and Rowe scores were used for the clinical evaluation. Patients were divided in 3 groups based on the percentage of bone loss: group 1: <8%; group 2: 8% to 17%; and group 3: >17%. ResultsThe recurrence rate was 7% (3/43 shoulders). A weak negative correlation was seen between bone loss and Sports/Recreation/Work domain of the WOSI score (r=−0.304, p=0.0191). The WOSI for group 3 was significantly lower than that for groups 1 and 2 (p=0.0009). The male WOSI scores were significantly lower than the female ones (p=0.0471). The WOSI scores of the contact athletes were significantly lower than those of noncontact athletes (p=0.0275). All the patients in Group 3 were males and participated in contact sports. ConclusionGlenoid bone loss between 17 and 25% is considered to be a “subcritical bone loss” in our series, especially in male patients who are involved in sports or high-level activities. Level of evidenceIII, retrospective study.

High bone microarchitecture, strength, and resistance to bone loss in MRL/MpJ mice correlates with activation of different signaling pathways and systemic factors.

The MRL/MpJ mice have demonstrated an enhanced tissue regeneration capacity for various tissues. In the present study, we systematically characterized bone microarchitecture and found that MRL/MpJ mice exhibit higher bone microarchitecture and strength compared to both C57BL/10J and C57BL/6J WT mice at 2, 4, and 10 months of age. The higher bone mass in MRL/MpJ mice was correlated to increased osteoblasts, decreased osteoclasts, higher cell proliferation, and bone formation, and enhanced pSMAD5 signaling earlier during postnatal development (2-month old) in the spine trabecular bone, and lower bone resorption rate at later age. Furthermore, these mice exhibit accelerated fracture healing via enhanced pSMAD5, pAKT and p-P38MAPK pathways compared to control groups. Moreover, MRL/MpJ mice demonstrated resistance to ovariectomy-induced bone loss as evidenced by maintaining higher bone volume/tissue volume (BV/TV) and lower percentage of bone loss later after ovariectomy. The consistently higher serum IGF1 level and lower RANKL level in MRL/MpJ mice may contribute to the maintenance of high bone mass in uninjured and injured bone. In conclusion, our results indicate that enhanced pSMAD5, pAKT, and p-P38MAPK signaling, higher serum IGF-1, and lower RANKL level contribute to the higher bone microarchitecture and strength, accelerated healing, and resistance to osteoporosis in MRL/MpJ mice.

Effect of subcritical glenoid bone loss on activities of daily living in patients with anterior shoulder instability

BackgroundIt has been biomechanically demonstrated that 20% to 25% is a critical glenoid bone loss. Recently, there are several reports describing that a bone loss less than 20% to 25% needed to be treated because patients may have decreased quality of life without recurrent instability events. The purpose of this study was to clarify the presence of subcritical bone loss that would affect postoperative instability or quality of life. MethodsSubjects were 43 patients aged≤40years with less than 25% glenoid bone loss who had undergone arthroscopic Bankart repair. These patients were assessed at a mean follow-up of 32months. The Western Ontario Shoulder Instability (WOSI) and Rowe scores were used for the clinical evaluation. Patients were divided in 3 groups based on the percentage of bone loss: group 1: <8%; group 2: 8% to 17%; and group 3: >17%. ResultsThe recurrence rate was 7% (3/43 shoulders). A weak negative correlation was seen between bone loss and sports/recreation/work domain of the WOSI score (r=−0.304, p=0.0191). The WOSI for group 3 was significantly lower than that for group 1 and 2 (p=0.0009). The male WOSI scores were significantly lower than the female ones (p=0.0471). The WOSI scores of the contact athletes were significantly lower than those of non-contact athletes (p=0.0275). All the patients in Group 3 were males and participated in contact sports. ConclusionGlenoid bone loss between 17% and 25% is considered to be a “subcritical bone loss” in our series, especially in male patients who are involved in sports or high-level activities. Level of evidenceIII, retrospective study.

Characterization of Posterior Glenoid Bone Loss Morphology in Patients With Posterior Shoulder Instability

To systemically describe posterior bone defects in the setting of posterior shoulder instability based on several parameters, including surface area, slope and version, defect height from the base of the glenoid, and extent of bone loss at equal intervals along the long axis of the fossa. A total of 40 young, active individuals with recurrent posterior shoulder instability and a bony injury confirmed on either computed tomography (n= 18; mean age, 26.3 ± 4.0years) or magnetic resonance imaging (n= 22; mean age, 20.0 ± 4.9years) were identified. The posterior glenoid bone defect was characterized using the following measures: (1) percentage of bone loss, (2) glenoid vault version, (3) slope of the posterior defect relative to the glenoid surface, (4) superior-inferior length of the defect, and (5) anterior-posterior width of the defect at 5 intervals along the glenoid fossa. The mean age of the 40 patients was 22.9 ± 5.5years (range, 14.9-35.5years). The mean surface area of glenoid bone loss was 9.7% ± 4.7%. Glenoid version measured at 5 equal intervals along the inferior two-thirds of the glenoid was 12.8° ± 4.9°, 11.9° ± 5.0°, 10.1° ± 6.3°, 10.5° ± 6.5°, and 8.7° ± 7.2° from superior to inferior. The mean slope of the posterior defect relative to the glenoid fossa was 26.8° ± 11.5°. The mean superior-inferior height of the bony defect was 21.9 ± 0.4mm. The anterior-posterior sloped width of the defect at 5 equal intervals along the glenoid fossa was 0.9 ± 1.5mm, 2.8 ± 2.4mm, 4.0 ± 1.7mm, 4.0 ± 2.1mm, and 2.9 ± 2.6mm from superior to inferior. Low-grade (<10%) bone loss was diagnosed in most shoulders (23 of 40 evaluated), whereas 15 had moderate bone loss (10% to <20%) and 2 had high-grade bone loss (≥20%). Posterior glenoid bone loss is characterized by a loss of posterior bony concavity, increased slope from anterior to posterior, and increased posterior version. The most anterior-posterior sloped width was quantified at the third and fourth intervals of 5 equal intervals from superior to inferior. This study highlights that patients with posterior instability have bone loss that is sloped relative to the glenoid fossa and suggests that management must be appropriately tailored given the distinctiveness of posterior bone loss. Level IV, case series.

Is Return To Play At 6 Months After Latarjet Safe? A Multicenter Orthopaedic Outcomes Network (MOON) Shoulder Group Cohort Study

Objectives: The Latarjet procedure is the becoming increasingly popular for the treatment of young athletes with recurrent instability. Earlier return to play protocols have been trialed with the thought that one is primarily waiting on bone healing. However, the impact of post-operative range of motion (ROM) and strength must be considered as well. Return to play has traditionally been accepted at 6 months post-operatively, but it is unknown what percentage of athletes achieve full strength and range of motion at that point. The purpose of this study was to 1) To evaluate rates of return of full strength and range of motion at 6 months after Latarjet, and 2) determine whether rates of results vary by percent bone loss, subscapularis split versus tenotomy, or athlete status (contact or overhead). Methods: Ten participating sites throughout the United States enrolled patients in a multicenter prospective cohort study. Sixty-five athletes met inclusion criteria (mean age 24.5 SD 8.2; 59 male, 6 female) and underwent Latarjet procedure for anterior instability (19/65 (29%) primary operation, 46/65 (71%) had a prior failed anterior stabilization). All participated in either contact sports (83%) and/or overhead sports (37%). Regarding anterior glenoid bone loss, 10% had &lt;10% bone loss, 55% had 11-20%, and 35% had 21-30%. The Latarjet procedure was performed with either subscapularis tenotomy (64%) or split (36%). Strength and range of motion were assessed pre-operatively and at 6 months after surgery. Return to play (RTP) criteria were defined as full strength as well as less than 20 degrees side-to-side ROM deficits in all planes. The independent likelihood of strength and motion RTP criteria at 6 months for percent bone loss as well as subscapularis tenotomy vs split was assessed with multivariate logistic regression modeling with adjustment as needed for age, sex, preoperative strength/motion, number of prior dislocations, and participation in contact versus overhead sports. Results: 45% of patients failed to meet one or more return to play criteria: 9% failed for persistent weakness and 39% for ≥ 20 degree side to side loss of motion. All patients with loss of motion had ≥ 20 degree external rotation (ER) deficits either with elbow at side (88%) or at 90 degrees abduction (44%). There was no difference in achieving RTP criteria at 6 months between subscapularis split versus tenotomy either for strength (p=0.89) or range of motion (p=0.53). Contact athletes had a 53% RTP rate while overhead athletes had a 67% passage rate (p=0.17). Pre-operative weakness was not significantly predictive of post-operative weakness (p=0.13), and pre-operative external rotation was not predictive of post-operative ER deficits (p=0.16). Percent bone loss was not predictive of side-to side post-operative ROM deficits or weakness (p&gt;0.20 all planes of motion). No other predictors for failure to meet RTP criteria at 6 months were identified. Conclusion: A large percentage of athletes do not have full return of strength and range of motion at 6 months following Latarjet procedure. Further consideration may be warranted prior to releasing these athletes to contact sports.

CLINICAL AND RADIOGRAPHIC VARIABLES ASSOCIATED WITH MEDICATION-RELATED OSTEONECROSIS OF THE JAW (MRONJ) IN PATIENTS WITH MULTIPLE MYELOMA—A RETROSPECTIVE STUDY

Background Medication-related osteonecrosis of the jaws (MRONJ), which causes exposed bone in the maxillofacial region, persisted for 8 weeks in a patient who was receiving a bone-modulating agent.1 Multiple myeloma (MM) is a hematologic cancer that can cause bone disease. Therefore, a potent bisphosphonate is used to control bone metastasis, but one of its adverse effects is MRONJ. Previous studies that investigated risk factors associated with MRONJ were done in patients with different hematologic conditions, where the underlining condition might affect the result.2-4 Objective The aim of this study was to evaluate the possible risk factors associated with MRONJ in patients with MM. Materials and Methods The institutional review board approved the study. We reviewed the medical charts, including digital radiographs, of 116 patients with MM, 16 of whom had developed MRONJ; these patients had attended the oral medicine clinic at the University of Florida College of Dentistry between 2011 and 2015. The following information was retrieved: age, gender, smoking, type and duration of bisphosphonate pressure treatment, and periodontal status. Periodontal bone loss was measured from a digital pantomograph as a percentage of missing bone at the mesial and distal surfaces of each tooth. These measurements were averaged to yield a single mean bone loss score for each patient.5 Using radiographs, in place of clinical examination, to determine periodontal bone loss has been validated in earlier studies.6,7 The variables predictive of MRONJ development were calculated by using SPSS software (SPSS Inc., Chicago, IL). Results Patients with MRONJ had significantly higher percentage of bone loss (odds ratio [OR] 6.06; P < .001). Patients who had greater than 15 missing teeth were at higher risk of MRONJ (OR 5.7; P = .005). No statically significant association was found with regard to the other variables. Conclusions Tooth loss and advanced bone loss are significant risk factors of MRONJ in patients with MM. This study was limited to radiologic examination, and no clinical periodontal examination was performed. The usefulness of radiographs can be limited by the technique used because some can cause distortion and affect the measurements. Medication-related osteonecrosis of the jaws (MRONJ), which causes exposed bone in the maxillofacial region, persisted for 8 weeks in a patient who was receiving a bone-modulating agent.1 Multiple myeloma (MM) is a hematologic cancer that can cause bone disease. Therefore, a potent bisphosphonate is used to control bone metastasis, but one of its adverse effects is MRONJ. Previous studies that investigated risk factors associated with MRONJ were done in patients with different hematologic conditions, where the underlining condition might affect the result.2-4 The aim of this study was to evaluate the possible risk factors associated with MRONJ in patients with MM. The institutional review board approved the study. We reviewed the medical charts, including digital radiographs, of 116 patients with MM, 16 of whom had developed MRONJ; these patients had attended the oral medicine clinic at the University of Florida College of Dentistry between 2011 and 2015. The following information was retrieved: age, gender, smoking, type and duration of bisphosphonate pressure treatment, and periodontal status. Periodontal bone loss was measured from a digital pantomograph as a percentage of missing bone at the mesial and distal surfaces of each tooth. These measurements were averaged to yield a single mean bone loss score for each patient.5 Using radiographs, in place of clinical examination, to determine periodontal bone loss has been validated in earlier studies.6,7 The variables predictive of MRONJ development were calculated by using SPSS software (SPSS Inc., Chicago, IL). Patients with MRONJ had significantly higher percentage of bone loss (odds ratio [OR] 6.06; P < .001). Patients who had greater than 15 missing teeth were at higher risk of MRONJ (OR 5.7; P = .005). No statically significant association was found with regard to the other variables. Tooth loss and advanced bone loss are significant risk factors of MRONJ in patients with MM. This study was limited to radiologic examination, and no clinical periodontal examination was performed. The usefulness of radiographs can be limited by the technique used because some can cause distortion and affect the measurements.

Management of Recurrent Anterior Shoulder Instability With Bipolar Bone Loss: A Systematic Review to Assess Critical Bone Loss Amounts

Background: There is increasing evidence to suggest that the amount of glenoid bone loss to indicate bone block procedures may be lower than previously thought, particularly in the presence of a Hill-Sachs defect. Purpose: To better establish treatment recommendations for anterior shoulder instability among patients with bipolar bone lesions. Study Design: Systematic review and meta-analysis; Level of evidence, 4. Methods: A systematic review of the literature was performed with PubMed, EMBASE, Cochrane Library, and Scopus databases according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. Studies evaluating outcomes of operative management in anterior shoulder instability that also reported glenoid bone loss in the presence of Hill-Sachs defects were included. Recurrence rates, glenoid bone loss, and humeral bone loss were pooled and analyzed with forest plots stratified by surgical procedure. Methods of quantification were analyzed for each article qualitatively. Results: Thirteen articles were included in the final analysis, with a total of 778 patients. The mean ± SD age was 24.9 ± 8.6 years. The mean follow-up was 30.1 months (range, 11-240 months). Only 13 of 408 (3.2%) reviewed bipolar bone loss articles quantified humeral and/or glenoid bone loss. Latarjet procedures had the greatest glenoid bone loss (21.7%; 95% CI, 14.8%-28.6%), followed by Bankart repairs (13.1%; 95% CI, 9.0%-17.2%), and remplissage (11.7%; 95% CI, 5.5%-18.0%). Humeral bone loss was primarily reported as percentage bone loss (22.2%; 95% CI, 13.1%-31.3% in Bankart repairs and 31.7%; 95% CI, 21.6%-41.1% in Latarjet) or as volumetric defects (439.1 mm3; 95% CI, 336.3-541.9 mm3 in Bankart repairs and 366.0 mm3; 95% CI, 258.4-475.4 mm3 in remplissage). Recurrence rates were as follows: Bankart repairs, 19.5% (95% CI, 14.5%-25.8%); remplissage, 4.4% (95% CI, 1.3%-14.0%); and Latarjet, 8.7% (95% CI, 5.0%-14.7%). Bankart repairs were associated with significantly greater recurrence of instability in included articles (P = .013). Conclusion: There exists a need for universal and consistent preoperative measurement of humeral-sided bone loss. The presence of concomitant Hill-Sachs defects with glenoid pathology should warrant more aggressive operative management through use of bone block procedures. Previously established values of critical glenoid bone loss are not equally relevant in the presence of bipolar bone loss.

A Clinical Comparison of Linear- and Surface Area–Based Methods of Measuring Glenoid Bone Loss

Background: The purpose of this study was to determine whether linear-based measurement significantly overestimates glenoid bone loss in comparison with surface area–based measurement in patients with recurrent anterior shoulder instability and glenoid bone loss. Hypothesis: Linear-based measurement will significantly overestimate glenoid bone loss in comparison with surface area–based measurement in patients with anterior shoulder instability and glenoid bone loss. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: Thirty patients with anterior shoulder instability underwent preoperative bilateral shoulder computed tomography (CT) scans. Three-dimensional CT (3D-CT) reconstruction with humeral head subtraction was performed to obtain an en face view of the 3D-CT glenoid. Glenoid bone loss was measured with the surface area and linear methods of measurement. Statistical analysis was performed with a paired 2-tailed t test. Results: Twenty-eight patients (5 female and 23 male; mean age, 25.1 years; age range, 15-58 years) were included in the study; 17 patients underwent a glenoid augmentation procedure, and 11 underwent arthroscopic Bankart repair. The mean percentage glenoid bone loss calculated with the surface area and linear methods was 12.8% ± 8.0% and 17.5% ± 9.7% (P < .0001), respectively. For the 17 patients who underwent glenoid augmentation, mean percentage bone loss with the surface area and linear methods was 16.6% ± 7.9% and 23.0% ± 8.0% (P < .0001), respectively. Conclusion: Linear measurement of glenoid bone loss significantly overestimates bone loss compared with surface area measurement in patients with anterior glenoid bony defects. These results indicate that these different methods cannot be used interchangeably and cannot be used with the same critical thresholds for glenoid bone loss.

Arthroscopic assessment of glenoid bone defect in patients with anterior shoulder instability

Purpose The purpose of this study was to assess the reliability of arthroscopic estimation of anterior glenoid bone defect in patients with anterior shoulder instability, by comparing it with anteroposterior diameter equation method in computed tomography (CT) glenoid en-face view with head subtraction. Patients and methods Thirty patients with anterior shoulder instability underwent shoulder CT glenoid en-face view scans and were found to have anterior glenoid bone defect. The anterior glenoid bone loss of each patient was studied using the anteroposterior distance from the center of a best-fit circle drawn on the inferior portion of the glenoid. Arthroscopic estimation of the anterior glenoid bone defect was done in all those patients as a part of the planned final procedure. The mean percent bone loss studied in CT was compared with arthroscopy to determine the reliability of arthroscopy in the measurement of anterior glenoid bone defect. Results The mean percentage of anterior glenoid bone defect calculated with CT diameter equation method was 17.3±9.7, whereas the mean percentage of arthroscopic estimation of anterior glenoid bone defect was 22.55±9.9, which shows statistically significant difference (P Conclusion Our finding suggests that arthroscopy significantly overestimates anterior glenoid bone defect compared with CT glenoid en-face view anteroposterior distance method, and the surgeons should not relay on arthroscopic measurement of the defect to plan for surgery.

Reduced kidney function is associated with BMD, bone loss and markers of mineral homeostasis in older women: a 10-year longitudinal study

SummaryKidney function decreases with age; however, the long-term influence on bone density (BMD) in older women already at risk of osteoporosis is unknown. We followed kidney function and bone loss for 10 years. Declining kidney function was adversely associated with bone loss and mineral homeostasis in old women, though it attenuated with advanced aging.IntroductionExisting studies do not fully address the relationship between kidney function and bone metabolism with advanced aging in Caucasian women. This study describes the association between kidney function, BMD, bone loss and bone metabolism in older women and provides a review of the available literature for context.MethodsWe studied participants from the OPRA cohort with follow-up after 5 and 10 years. Using plasma cystatin C (cysC), estimated glomerular function rate (eGFR) was evaluated at age 75 (n = 981), 80 (n = 685) and 85 (n = 365). Women were stratified into “normal” function (CKD stages 1–2), “intermediate” (stage 3a) and “poor” (stages 3b–5), and outcome measures—BMD, bone loss and markers of mineral homeostasis—were compared.ResultsFemoral neck (FN) BMD positively associated with kidney function at 75 years old ( widehat{beta} = 0.001, p = 0.028) and 80 years old ( widehat{beta} = 0.001, p = 0.001), although with small effect size. Prevalence of osteoporosis (FN T-score ≤ − 2.5) did not differ with kidney function. Measured at age 75, women with poor kidney function had higher annual percentage bone loss over 5 years compared to those with normal function (2.3%, 95% CI 1.8–2.8 versus 1.3%, 95% CI 1.1–1.5, p = 0.007), although not when measured from age 80 or 85. Additionally, markers of mineral homeostasis (PTH, phosphate, vitamin D, calcium), CRP and osteocalcin differed by kidney function.ConclusionsIn old women, kidney function is associated with BMD, bone loss and altered mineral homeostasis; probably, a relationship attenuated in the very elderly.

Correlation of Three-Dimensional Radiologic Data with Subsequent Treatment Approach in Patients with Peri-implantitis: A Retrospective Analysis.

The purpose of this retrospective radiographic study was to evaluate and correlate the dimensions and morphology of peri-implant bone defects as determined via cone beam computed tomography (CBCT) scans with regard to the selected treatment approach. Vertical and horizontal peri-implant bone defects (mesial, distal, mesio-oral, mesiobuccal, disto-oral, distobuccal, oral, and buccal) in peri-implantitis cases were measured. Three-dimensional data and defect morphology were correlated to the treatment approach chosen (explantation versus implant retention). A total of 19 patients and 28 implants met the inclusion criteria, resulting in a sample size of 224 sites and a total of 896 measurements. The mean percent bone loss did not correlate to the type of treatment chosen (P = .1286). In contrast, when only the maximum vertical values per implant were selected, maximum percent bone loss exhibited a significant correlation to the type of treatment chosen (P = .0021). The effect of the defect morphology on the treatment strategy chosen did not show a statistically significant correlation (P = .4685). Based on the data presented, the maximum bone loss around the implant seems to be a critical factor in deciding whether or not an implant should be explanted. The use of CBCT for treatment planning in cases of peri-implantitis can offer valuable additional information but should be considered only after initial clinical examination and two-dimensional imaging.

Bipolar Bone Loss in Patients With Anterior Shoulder Dislocation: A Comparison of Adolescents Versus Adult Patients

To compare bipolar bone loss by evaluating the degree of glenoid bone loss, Hill-Sachs lesion size, and glenoid track in adolescents and adults with shoulder dislocations. We performed a retrospective review between 2012 and 2016 of surgical and nonsurgical patients with a history of anterior shoulder dislocations (primary or recurrent) who underwent magnetic resonance imaging of the affected shoulder. The exclusion criteria included multidirectional instability, prior surgery, and posterior dislocation. Patients were grouped into 2 groups: adolescents (aged 10-19years) and adults (aged ≥20years). The groups were compared regarding measures of glenoid bone loss (best-fit circle technique) and Hill-Sachs lesion size (medial margin of rotator cuff footprint to medial margin of Hill-Sachs lesion). If the medial margin of a Hill-Sachs lesion was within the glenoid track, it was defined as on track; if it was more medial than the glenoid track, it was defined as off track. We identified 45 adolescents (mean age, 16.1years) and 30 adults (mean age, 28.9years) with anterior shoulder dislocations. There was no significant difference in percentage of bone loss between adolescents (mean, 8.4%) and adults (mean, 9.9%; P= .23). There was no significant difference in Hill-Sachs lesion size between adolescents (mean, 12.7mm) and adults (mean, 9.9mm; P= .12). There were 12 patients with off-track lesions. Off-track lesions were present in 11 of 45 adolescents (24.4%) and 1 of 30 adults (3.3%). Adolescents had an increased risk of having an off-track lesion (odds ratio, 9.38; 95% confidence interval, 1.14-77.1). A subgroup analysis identified multiple dislocations as an independent risk factor for an off-track lesion (odds ratio, 4.15; 95% confidence interval, 0.85-20.23). This study shows that adolescence and a history of multiple dislocations are independent risk factors for a greater likelihood of glenoid off-track lesions. The findings support the use of bipolar assessment of shoulder dislocators, especially in adolescents and multiple dislocators. Level III, retrospective comparative study.

Posterior Shoulder Instability with Glenoid Bone Loss: Morphology of Posterior Bone Defects

Although much less common than anterior shoulder instability with glenoid bone loss, posterior glenoid bone defects leading to shoulder instability are severely limiting and significantly affect a patient's quality of life. Moreover, given the rarity of incidence of this pathology, posterior instability with bone loss has been much less investigated in comparison to anterior instability. Given this paucity in literature, we sought to better define the geometrical pattern of posterior bone defects. The purpose of this study was to geometrically describe posterior bone defects based on slope and version as well as extent of bone loss along equal intervals spanning the long axis of the glenoid fossa. A total of forty young, active individuals with recurrent posterior shoulder instability and a bony injury confirmed on either computed tomography (CT) (n=18, 26.3±4.0 years) or magnetic resonance imaging (MRI) (n=22, 20.0±4.9 years) were identified. The posterior glenoid bone defect was characterized using the following measures: (a) percent bone loss; (b) glenoid vault version; (c) the slope of the posterior defect relative to the glenoid surface; (d) the superior-inferior height of the defect; and (e) the anterior-posterior width of the defect at five intervals along the glenoid fossa. Posterior glenoid bone loss morphology was characterized by MRI and CT as more sloped relative to the glenoid than the more perpendicular pattern of bone loss seen in anterior instability. Although CT featured a more severe pattern of bone loss, including greater glenoid version and a greater slope of the posterior defect, this pattern of glenoid bone loss remained consist regardless of the imaging modality. Posterior glenoid bone loss morphology differs considerably from its anterior counterpart. Therefore, this affirms the notion that shoulder instability with bone loss should not be grouped all together, but treated on a case-by-case basis given the direction of instability.

COMPARISON BETWEEN THE EFFECT OF CONVENTIONAL REMOVABLE PARTIAL DENTURES AND TELESCOPIC REMOVABLE PARTIAL DENTURES ON POCKET DEPTHS AND ALVEOLAR BONE HEIGHT OF ABUTMENT TEETH

Objective: this study was conducted to compare the effect of the conventional removable partial dentures (RPDs) and telescopic partial dentures on pocket depths and alveolar bone height of abutment teeth after a follow-up period of one year.Materials and Methods: twenty eight patients with mandibular bilateral free-end saddle were selected for this study, with canines and first premolars as last standing abutments on both sides and an opposing maxillary dentulous arch. They were randomly divided into two groups, group I receiving a conventional RPD, and group II receiving a telescopic partial denture. CAD/CAM technology was used for the fabrication of Polymethylmethacrylate patterns for both copings and frameworks for the two groups followed by casting in the conventional manner. Radiographic bone height measurements and pocket depth measurements were performed for the two groups at denture delivery and after one year.Results: there was no significant difference in percentage bone loss and pocket depth between the two groups after one year. However, only group II showed a significant increase in pocket depth after one year of follow-up. There was also an increase in bone loss in both groups after one year but it was not significant. Conclusion: Minor changes in pocket depths and alveolar bone height were observed in both groups. However, the telescopic partial denture showed signs of gingival inflammation and increased pocket depths, while the conventional removable partial denture showed more favorable results.

BIOMECHANICAL BEHAVIOR OF THREE SOLITARY IMPLANTS SUPPORTING MANDIBULAR OVERDENTURE: A RADIOGRAPHIC EVALUATION

Objective: Bone assessment around three implants supporting mandibular overdentureMethodology: Ten completely edentulous patient were meticulously selected to receive a mandibular overdenture retained by three un-splinted implants placed in the anterior region with ball and socket attachments. Mesial and distal bone for the three implants levels were monitored at the time of denture delivery, 6 and 12months.Results: The results of this study revealed insignificant difference between the bone level and percentage of bone loss for the three implants along the whole study period. Conclusion: The three-implant overdenture treatment can achieve favorable results from a biomechanical point of view as well as peri-implant bone response

3D-MR vs. 3D-CT of the shoulder in patients with glenohumeral instability.

To determine whether 3D-MR osseous reformats of the shoulder are equivalent to 3D-CT osseous reformats in patients with glenohumeral instability. Patients with glenohumeral instability, who were to be imaged with both CT and MRI, were prospectively selected. CT and MR were performed within 24h of one another on 12 shoulders. Each MR study included an axial 3D isotropic VIBE sequence. The image data from the isotropic VIBE sequence were post-processed using subtraction and 3D software. CT data were post-processed using 3D software. The following measurements were obtained for both 3D-CT and 3D-MR post-processed images: height and width of the humeral head and glenoid, Hill-Sachs size and percent humeral head loss (if present), size of glenoid bone loss and percent glenoid bone loss (if present). Paired t-tests and two one-sided tests for equivalence were used to assess the differences between imaging modalities and equivalence. The measurement differences from the 3D-CT and 3D-MR post-processed images were not statistically significant. The measurement differences for humeral height, glenoid height and glenoid width were borderline statistically significant; however, using any adjustment for multiple comparisons, this failed to be significant. Using an equivalence margin of 1mm for measurements and 1.5% for percent bone loss, the 3D-MR and 3D-CT post-processed images were equivalent. Three-dimensional-MR osseous models of the shoulder using a 3D isotropic VIBE sequence were equivalent to 3D-CT osseous models, and the differences between modalities were not statistically significant.

Longitudinal assessment of marrow fat content using three-point Dixon technique in osteoporotic rabbits.

In this longitudinal pilot study, we aimed to investigate the intra-, interobserver, and scan-rescan reproducibility of marrow fat fraction (FF) measurements using three-point Dixon imaging in osteoporotic rabbits: comparison with histopathology. Twenty female rabbits were randomly assigned to sham-operation and ovariectomy in combination with daily methylprednisolone hemisuccinate groups (n = 10 per group). Marrow FF by three-point Dixon technique and bone density by dual-energy x-ray absorptiometry were assessed at baseline, 6 and 12 weeks after operation. Intra-, inter-reader, and scan-rescan reliability of FF measurements were evaluated using intraclass correlation coefficient (ICC) and Bland-Altman 95% limit of agreement. Histomorphometry was performed to quantify marrow adipocyte parameters. Intra- and inter-reader reproducibility of FF measurements was "substantial" (ICC = 0.984 and 0.978, respectively). Although the ICC for scan-rescan reliability was excellent (ICC = 0.962), increased measurement variability was observed using Bland-Altman plot. Relative to the sham-operated rabbits, the adipocytes mean diameter, density, and percent adipocytes area in the osteoporotic rabbits increased by 23.4%, 68.9%, and 117.0%, respectively. Marrow FF was positively correlated with the quantitative parameters of adipocytes, particularly with percent adipocyte area, but inversely associated with bone density. At the relatively early stage, the percentage of bone loss was similar to that of elevated fatty marrow in the osteoporotic rabbits; at the later stage, the change for the latter outweighed that of the former. Results of three-point Dixon technique demonstrated a very reproducible manner within and between observers and acceptable scan-rescan performance in the assessment of marrow fat in rabbits.

What Is the Critical Value of Glenoid Bone Loss at Which Soft Tissue Bankart Repair Does Not Restore Glenohumeral Translation, Restricts Range of Motion, and Leads to Abnormal Humeral Head Position?

Background: A general consensus has been formed that glenoid bone loss greater than 20% to 25% is the critical amount at which bony augmentation procedures are needed; however, recent clinical results suggest that the critical levels must be reconsidered to lower values. Purpose: This study aimed to find the critical value of anterior glenoid bone loss when a soft tissue repair is not adequate to restore anterior-inferior glenohumeral translation, rotational range of motion, or humeral head position using a biomechanical anterior shoulder instability model. Study Design: Controlled laboratory study. Methods: Eight cadaveric shoulders were tested with a customized shoulder testing system. Range of motion, translation, and humeral head position were measured at 60° of glenohumeral abduction in the scapular plane under a total of 40-N rotator cuff muscle loading in the following 11 conditions: intact; soft tissue Bankart lesion and repair; Bankart lesion with 10%, 15%, 20%, and 25% glenoid bone defects based on the largest anteroposterior width of the glenoid; and soft tissue Bankart repair for each respective glenoid defect. Serial osteotomies for each percentage of bone loss were made parallel to the long axis of the glenoid. Results: There was significantly decreased external rotation (121.2° ± 2.8° to 113.5° ± 3.3°; P = .004), increased anteroinferior translation with an externally applied load (3.0 ± 1.2 mm to 7.5 ± 1.1 mm at 20 N; P = .008), and increased posterior (0.2 ± 0.6 mm to 2.7 ± 0.8 mm; P = .049) and inferior shift (2.9 ± 0.7 mm to 6.6 ± 1.1 mm; P = .018) of the humeral head apex in the position of maximum external rotation after soft tissue Bankart repair of a 15% glenoid defect compared with the repair of a Bankart lesion without a glenoid defect, respectively. Conclusion: Glenoid defects of 15% or more of the largest anteroposterior glenoid width should be considered the critical bone loss amount at which soft tissue repair cannot restore glenohumeral translation, restricts rotational range of motion, and leads to abnormal humeral head position. Clinical Relevance: The critical level of anterior glenoid bone loss at which bony restorations should be considered is closer to 15% of the largest anteroposterior width of glenoid for defects perpendicular to the superoinferior glenoid axis, which is lower than the commonly accepted threshold of 20% to 25%.

Assessment and Evaluation of Glenoid Bone Loss

The preoperative assessment of anterior glenoid bone loss is a critical step in surgical planning for patients with recurrent anterior glenohumeral instability. The structural integrity of the glenoid has been identified as one of the most important factors influencing the success of operative repair. The currently accepted gold standard for glenoid structural assessment among most orthopaedic surgeons is the use of 3-dimensional reconstructed computed tomography images with the humeral head digitally subtracted, yielding an en face sagittal oblique view of the glenoid. This view allows for evaluation of glenoid morphology and quantitative assessment of glenoid bone loss. In this article, we describe the practical application of ImageJ software (National Institutes of Health, Bethesda, MD) to quantify the amount of glenoid bone loss reported as a percentage of either total surface area or diameter. The following equations are used in this technical note for the diameter-based method and surface area method, respectively: Percent bone loss = (Defect width/Diameter of inferior glenoid circle) × 100% and Percent bone loss = (Defect surface area/Surface area of inferior glenoid circle) × 100%.

Characterization of Posterior Glenoid Bone Loss

Objectives:The purpose of this study was to characterize the morphology and location of posterior glenoid bone loss in pat ients with posterior instability instability utilizing computed tomography (CT).Methods:Clinical data was selected for patients with posterior shoulder instability that had undergone posterior stabilization (open or arthroscopic) or posterior osseous augmentation (distal tibia or iliac crest). Three fellowship-trained surgeons from two institutions contributed patients. Pre-operative CT data was collected for all patients. The axial cuts were segmented and reformatted in three-dimensions for glenoid analysis using Osirix. From this three-dimensional model, the following was calculated: percent bone loss (Nobuhara), total arc of the defect (degrees), and a clock-face description (start point, stop point, and average or direction). Pearson correlation coefficients were performed using significance of p<0.05.Results:Fifty shoulders from 50 patients were reviewed. Fourteen patients (average age 30 years; 93% male) had evidence of posterior glenoid bone loss and were included for evaluation. Defects on average involved 13.7±8.6% of the glenoid (range, 2-35%). The average start time (assuming all right shoulders) on the clock face was 10 o’clock ± 40 minutes and stopped at 6:30 ± 25 minutes. The average direction of the defect pointed toward 8:15 ± 25 minutes. The percent bone loss correlated with the total arc of the defect (Pearson: 0.93, p<0.05, R2: 0.86) and the direction of the bone loss (Pearson: 0.64, p<0.05, R2: 0.40). The direction of bone loss significantly moved more posterosuperior the larger the defect became (Pearson: 0.63, p<0.05, R2: 0.40).Conclusion:Posterior bone loss associated with posterior glenohumeral instability is typically directed posteriorly at 8:15 on the clock. As defect get bigger, this direction moves more posterosuperior. This information will help guide clinicians in understanding the typical location of posterior bone loss aiding in diagnosis, cadaveric models, and treatment.