Bony Coverage Research Articles

Combined Lateral Osseolabral Coverage Is Normal in Hips With Acetabular Dysplasia

To compare the lateral osseolabral coverage between groups of patients with different degrees of acetabular bony coverage using a magnetic resonance imaging parameter known as the combined lateral center-edge angle (cLCEA). The cLCEA was measured among a consecutive series of patients presenting to a dedicated hip preservation surgeon with a magnetic resonance imaging scan. The cLCEA was measured using a coronal T1 or proton density image and was defined as the angle subtended by (1) a line through the center of the femoral head and orthogonal to the transverse line passing through the teardrops of both hips and (2) an oblique line drawn from the center of the femoral head to the free edge of the lateral acetabular labrum. The average difference between the lateral center-edge angle (LCEA) and the cLCEA was calculated and compared between groups based on acetabular bony coverage: dysplasia (LCEA <20°), borderline dysplasia (LCEA 20°-24.9°), normal coverage (LCEA 25°-39.9°), and overcoverage (LCEA ≥40°). In total, 341 patients (386 hips) were included. There were no significant differences in cLCEA between hips with normal acetabular coverage and dysplasia (P= .10) or borderline dysplasia (P= .46). Despite the large difference in mean LCEA between dysplasia (14.8° ± 3.9°) and acetabular overcoverage (43.1° ± 2.8°), the mean cLCEA values exhibited only a modest difference (44.7° ± 4.9° vs 52.7° ± 4.5°, respectively). Concordantly, hips with dysplasia exhibited the largest difference between mean LCEA and cLCEA (delta= 29.9° ± 4.7°) and hips with acetabular overcoverage had the smallest difference between measures (9.6° ± 5.2°). With decreasing acetabular bony coverage, there is increasing labral size such that the total osseolabral coverage, measured by the combined LCEA, remains equivalent between hips with normal acetabular coverage versus dysplasia. Level III, retrospective comparative study.

Rotational position of the tibial component can decrease bony coverage of the tibial component in Oxford mobile-bearing unicompartmental knee arthroplasty

BackgroundThis study examined how coverage of the tibial component changes when the tibia vertical cut is externally or internally rotated in Oxford mobile-bearing unicompartmental knee arthroplasty. Materials and methodsFifty patients scheduled for primary Oxford medial unicompartmental knee arthroplasty (UKA) at the current hospital were included in this study. This study was a computed tomography (CT) simulation study. The anteroposterior (AP) and mediolateral (ML) length as well as the ML/AP ratio of the tibial cut surfaces were calculated when the vertical cut was performed parallel (base line), five degrees externally rotated (ER5), 10° externally rotated (ER10), five degrees internally rotated (IR5), or 10° internally rotated (IR10) relative to the tibial AP line using pre-operative CT. The tibial AP line connecting the middle of the posterior collateral ligament to the medial border of the patellar tendon attachment is a reproducible and reliable line because it is perpendicular to the SEA. These parameters among three lines were compared using a repeated measures ANOVA. ResultsThe mean ML/AP ratios were statistically significantly lower in ER5 (0.53 ± 0.04) than base line (0.56 ± 0.04) (P < 0.01). The ER10 (0.48 ± 0.03) also exhibited lower mean ML/AP ratios than ER5 (0.53 ± 0.04) (P < 0.01). The mean ML/AP ratios were higher in IR5 (0.59 ± 0.04) than base line (0.56 ± 0.04) (P < 0.01). The IR10 (0.63 ± 0.06) also showed a higher mean ML/AP ratio than IR5 (0.59 ± 0.04) (P < 0.01). ConclusionRotational malalignment of tibial vertical cuts can affect tibial coverage in Oxford mobile-bearing unicompartmental knee arthroplasty.

Microinstability of the Hip-Gaining Acceptance.

The hip has generally been considered an inherently stable joint. However, the femoral head moves relative to the acetabulum. Although the bones are primarily important in hip stability, the importance of the soft tissues has recently been demonstrated. Symptomatic microinstability of the hip is defined as extraphysiologic hip motion that causes pain with or without symptoms of hip joint unsteadiness and may be the result of bony deficiency and/or soft-tissue damage or loss. Recent work has helped improve the ability to identify microinstability patients preoperatively. Initial management begins with activity modification and strengthening of the periarticular musculature. Failing nonsurgical management, surgical intervention can be beneficial, focusing on treatment of the underlying cause of microinstability, as well as associated intra-articular pathology. Bony deficiency may be treated with a redirectional osteotomy, whereas those with adequate bony coverage may be treated with capsular plication, capsular reconstruction, and/or labral reconstruction.

Superior Canal Dehiscence: A Comparative Postmortem Multislice Computed Tomography Study.

ObjectiveSuperior canal dehiscence is defined by missing bony coverage of the superior canal against the middle cranial fossa. The gold standard in diagnosis is high-resolution computed tomography (CT). A false-positive CT scan, identifying a dehiscence when one is not present, could lead to unnecessary surgical therapy. This study aims to compare postmortem CT scans with autopsy findings with regard to superior canal dehiscence.Study DesignPostmortem study.SettingTertiary referral center.Subjects and MethodsTwenty-two nontraumatic death cases within a 3-month period (January to March 2017) were included with 44 temporal bones. Each body underwent postmortem head CT prior to medicolegal autopsy. The middle fossa floor was exposed, and if present, the superior semicircular canal dehiscence was identified and measured. In each case, 3 comparable photographs were taken during the autopsy (left temporal bone, right temporal bone, overview).ResultsAutopsy findings revealed bony dehiscences in 11% of the temporal bones, whereas CT scan revealed bony dehiscences in 16%. The length of the dehiscences were longer when measured by CT imaging.ConclusionThe diagnosis of superior canal dehiscence syndrome requires high-resolution CT with clinical symptoms and physiologic evidence of a third mobile window. Our study underlines a mismatch between multislice CT imaging in the coronal plane and the presence of a dehiscence on autopsy.

Standardizing the Prearthritic Hip Joint Space Width: An Analysis of 994 Hips

The purposes of this study were (1) to define a normal prearthritic hip joint space width (JSW) in symptomatic and asymptomatic patients with various degrees of acetabular coverage based on the lateral center edge angle (LCEA) and (2) to determine predictors of JSW using patient-specific variables. In a consecutive series of patients presenting to a hip preservation clinic between July 2012 and April 2016, a standard weight-bearing anteroposterior pelvic view was obtained. JSW was defined as the distance between the bony contour of the acetabular rim and femoral head in 2 locations (lateral and medial weight-bearing zone). Hips with severe anatomic deformity, a Tönnis grade >0, or a lateral or medial JSW <2.5mm were excluded. A linear mixed model analysis was performed in order to determine which variables (age, sex, side, height, weight, symptomatic/asymptomatic, LCEA, and clinical diagnosis) were significantly related to JSW. A total of 994 hips were included. LCEA was found to be a significant predictor of both the lateral and medial JSW, with a decreased JSW associated with increasing degrees of acetabular bony coverage (P < .02). A mean 0.9mm (20%) difference in medial JSW was found between patients with frank dysplasia (LCEA <20°) compared with those with pincer-type FAI (LCEA ≥40°). There was no difference between symptomatic and asymptomatic hips, either for lateral (asymptomatic: 4.51 ± 0.83mm; symptomatic: 4.52 ± 0.85mm; P= .58) or medial JSW (asymptomatic: 4.02±0.96mm; symptomatic: 3.97 ± 0.84mm; P= .49). The LCEA is a significant predictor of hip JSW, with the mean JSW decreasing with increasing degrees of acetabular bony coverage. Joint space is not a major factor in symptomatology in adults with prearthritic hip pain. Level III, retrospective comparative study.

Long-term retrospective study on the placement of the cementless acetabular cup and clinical outcomes in patients undergoing femoral head autografting for hip dysplasia and total hip arthroplasty.

Placement of acetabular cup in the dysplastic hip is a challenging procedure. Using bulk femoral headautograft to increase the bony coverage of the cup is one of the techniques, which have been described. Theimpact of cup position on cup and autograft survival is a controversial issue. We aimed to determine whether the position of cementless acetabular cup used in conjunction with femoral head autograft in dysplastic hips affected the autograft-host incorporation with its final radiographic appearance and the cup survivorship into the second decade. Thirty-eight dysplastic hips with varying Crowe types in 31 patients (30 women and one man) were included. The mean age was 47 years (range, 29-64 years) and the mean follow-up was 20.3 years (range, 14.8-25.9 years). The initial postoperative and final radiographs were evaluated. The survival rate of the cups was analysed using Kaplan-Meier statistics and the log-rank test. Multivariate analysis was used to evaluate the effect of variables (Crowe type, radiographic initial host bone coverage over the cup and position of the cup) on survivorship. The acetabular cups were positioned anatomical in 27/38 hips according to Ranawat measurement technique. Trabecular bridging at graft-host interface was seen in all cases at an average 22.1 months. Neither acetabular cup position nor initial host bone coverage over acetabular cup less than 50% had any significant effect on either cup survival or final radiographic appearance of the graft. The 20-year cup survival rate without aseptic revision was 66% (95 CI, 52%-84%). No revision was performed due to graft resorption. Twenty-year survival rate of the cementless cup combination with femoral head autograft showed no significant differences whether it was placed at high or anatomic hip centre. The final radiographic appearance of the autograft was not affected from either the cup location or the initial radiographic horizontal host bone coverage.

Evaluation of the three-dimensional bony coverage before and after rotational acetabular osteotomy.

Rotational acetabular osteotomy is a type of pelvic osteotomy that involves rotation of the acetabular bone to improve the bony coverage of the femoral head for patients with acetabular dysplasia. Favourable post-operative long-term outcomes have been reported in previous studies. However, there is a paucity of published data regarding three-dimensional bony coverage. The present study investigated the three-dimensional bony coverage of the acetabulum covering the femoral head in hips before and after rotational acetabular osteotomy and in normal hips. The computed tomography data of 40 hip joints (12 joints before and after rotational acetabular osteotomy; 16 normal joints) were analyzed. The three-dimensional bony coverage of each joint was evaluated using original software. The post-operative bony coverage improved significantly compared with pre-operative values. In particular, the anterolateral aspect of the acetabulum tended to be dysplastic in patients with acetabular dysplasia compared to those with normal hip joints. However, greater bony coverage at the anterolateral aspect was obtained after rotational acetabular osteotomy. Meanwhile, the results of the present study may indicate that the bony coverage in the anterior aspect may be excessive. Three-dimensional analysis indicated that rotational acetabular osteotomy achieved favorable bony coverage. Further investigations are necessary to determine the ideal bony coverage after rotational acetabular osteotomy.

Do modern total knee replacements improve tibial coverage?

The purpose of the present study is to compare newer designs of various symmetric and asymmetric tibial components and measure tibial bone coverage using the rotational safe zone defined by two commonly utilized anatomic rotational landmarks. Computed tomography scans (CT scans) of one hundred consecutive patients scheduled for total knee arthroplasty were obtained pre-operatively. A virtual proximal tibial cut was performed and two commonly used rotational axes were added for each image: the medio-lateral axis (ML-axis) and the medial 1/3 tibial tubercle axis (med-1/3-axis). Different symmetric and asymmetric implant designs were then superimposed in various rotational positions for best cancellous and cortical coverage. The images were imported to a public domain imaging software, and cancellous and cortical bone coverage was computed for each image, with each implant design in various rotational positions. One single implant type could not be identified that provided the best cortical and cancellous coverage of the tibia, irrespective of using the med-1/3-axis or the ML-axis for rotational alignment. However, it could be confirmed that the best bone coverage was dependent on the selected rotational landmark. Furthermore, improved bone coverage was observed when tibial implant positions were optimized between the two rotational axes. Tibial coverage is similar for symmetric and asymmetric designs, but depends on the rotational landmark for which the implant is designed. The surgeon has the option to improve tibial coverage by optimizing placement between the two anatomic rotational alignment landmarks, the medial 1/3 and the ML-axis. Surgeons should be careful assessing intraoperative rotational tibial placement using the described anatomic rotational landmarks to optimize tibial bony coverage without compromising patella tracking. III.

Assessment of Pain and Trismus and Determining the Difficulty Level of Tooth Extraction with Modified Parant Scale

Introduction: Third molar extraction is the most commonly performed procedure by oral and maxillofacial surgeons and most of the extraction leads to minimum pre and post operative difficulties if proper preoperative planning is done and if surgical principles are strictly followed.Objective: This study evaluated whether pre and post operative pain and trismus were related to difficulty of surgery.Methodology: Total number of patients included in this study were 266 (male 135 and female 131), age range from 18 to 34 years. Preoperative diagnosis was made by clinical examination and radiographs. Clinical examination was done to determine pain, swelling and mucosal coverage of tooth whereas OPG and RVG were taken to assess the angulations, level of tooth impaction and bony coverage of tooth. Standardized technique was used for tooth extraction; buccal guttering, adequate elevation, reflection of mucoperiosteal flap, crown sectioning and ostectomy. Evaluation of pain and trismus was done preoperatively, on first and third post operative day. SPSS version 16 was used to analyse the data. Chi square (x²) test and unpaired 't' test were done. Modified Parant Scale was used to evaluate the difficulty of tooth extraction; Group I: forceps extraction; Group II: ostectomy; Group Ill: ostectomy and crown sectioning; Group IV: difficult extraction.Results: When both preoperative and postoperative results were compared after data analysis, pain was significantly reduced and significant inter incisal opening was achieved, in both the groups P &gt; 0.05. The results were statistically not significant.Conclusion: Postoperative pain and trismus was minimum in (Group I) then in (Group II to IV). The incidence of postoperative pain and trismus among all the groups were more or less similar. Hence, no significant difference was found. Birat Journal of Health SciencesVol.2/No.3/Issue 4/Sep- Dec 2017, Page: 282-286

The Relevant Roles of Plastic and Orthopedic Surgery in Hand Salvage

Over the recent past few years, there is a huge innovation in plastic surgery and orthopedic surgery through implantation of new techniques, which enabled a great level of success in hand salvage. Conditions such as trauma, tumor, sepsis, or vascular disease, may necessitate hand salvage. The most frequent argument among surgeon from different subspecialties (orthopedics, plastics, trauma, and vascular surgery) are characterized by in what way each one can do his own part of the salvage operation, be it bony fixation, revascularization, or soft-tissue coverage, but none of them is sure whether it should be endeavored. What is necessary in such clinical situations is an interdisciplinary team attitude led by individual or groups of clinicians who are conversant not only with their identifiable subspecialized skills but also with those of their coworkers and the consequences accompanying the joined efforts at hand salvage. The perception of orthoplastic surgery is based on such an indication, where the integrated skills and techniques of the orthopedic surgeon and reconstructive microsurgeon are performed in recital to direct efforts concerning hand salvage or choose against it when it is not designated. The current article reviews the roles of orthopedic and plastic surgery and how this team can deal with the existing techniques to improve outcomes in hand salvage surgery.

Residual hip dysplasia: A comparison of osseous and cartilaginous acetabular angles on MRI in children to guide further treatment

Introduction Despite improvements in early recognition and treatment of developmental dysplasia of the hip (DDH), residual hip dysplasia (RHD) continues to be a challenging clinical entity. Pelvic radiographs remain the standard in the follow up and evaluation of acetabular development, but can be insufficient to precisely evaluate the entire coverage of the femoral head, when trying to decide on the need for further reconstructive procedures in borderline RHD. We therefore introduced a new ratio comprised of the bony and cartilaginous acetabular angles measured on MRI in order to augment standard radiographs to aid clinicians in deciding if acetabuloplasty is needed. Materiel et methodes We retrospectively compared the bony and the cartilaginous acetabular angles of Hilgenreiner (HTE) in 30 children on pelvic MRI. Twenty children were followed up for DDH. The other 10 children had undergone a pelvic MRI for reasons other than DDH. RHD was defined by a bony HTE superior to 20°. Using standard radiographs, the 60 hips were separated into two groups: group 1 included the hips presenting RHD and group 2 the hips with a HTE below 20°. The hips in the two groups were then compared by introducing a new ratio calculated from the square of cartilaginous HTE above the bony HTE on frontal MRI. The normal upper limit for this acetabular angle ratio (AAR) was set at five and was extrapolated from the published normal values of C-HTE and O-HTE in children. Resultats The AAR was statistically significantly increased in the hips with RHD with a mean value of 7.1 (min.: 1.6, max.: 22.5) compared to the hips in the control group presenting a mean value of 2.1 (min.: 0.1, max.: 8.4) (P Discussion The cartilaginous part of the acetabulum seems to be an early and reliable predictor of acetabular development, as it's fully formed at birth and it is supposed to represent the bony margins of the acetabulum at adulthood after full ossification. The average C-HTE and O-HTE angles from the 27 healthy hips in group 2 corroborated with previous researches. An AAR above five means that not only the bony acetabular coverage is insufficient but also the cartilaginous part and therefore the hips have lower chance to normalize with growth. Moreover, an AAR from below five, even if RHD is seen on plain radiographs, indicates a sufficient cartilaginous coverage with an O-HTE that will correct with growth and we therefore renounce to perform an acetabuloplasty. Conclusion We recommend a pelvic MRI in children presenting borderline residual hip dysplasia on a plain radiography at the age of four and to perform acetabuloplasty if the AAR is superior to five.

Comparative evaluation of bony window preparation and coverage in maxillary sinus floor augmentation

Comparative evaluation of bony window preparation and coverage in maxillary sinus floor augmentation

How much does anatomical tibial component improve the bony coverage in total knee arthroplasty

How much does anatomical tibial component improve the bony coverage in total knee arthroplasty

How Much Does the Anatomical Tibial Component Improve the Bony Coverage in Total Knee Arthroplasty?

BackgroundRecently, anatomical designs in total knee arthroplasty are introduced to address asymmetry of the resected tibia cutting surface. It is still not well known how much improvement would be achieved in total knee arthroplasty, especially in Asian knees. MethodsWe evaluated the bony coverage of 4 commercially available posterior-stabilized tibial designs (3 symmetrical: NexGen, Attune, and Vega; 1 anatomical: Persona) by measuring uncovered areas over 3 different regions: lateroposterior (LP), medioposterior (MP), and mediolateral (ML) areas. The implant size was chosen based on lateral anteroposterior dimension of the implant that most closely matched the corresponding surface of tibia. The knee with over coverage <1 mm and under coverage <2 mm was regarded as having optimal fit. ResultsThe optimal fit of anatomical design in LP dimension was achieved in 76% of the cases, which was not significantly different from other symmetrical designs (P > .05). The anatomical tibial implant had a more optimal fit in MP and ML dimensions (48% and 42%, respectively) compared to all symmetric designs (P < .05). All symmetrical tibial designs had significant absolute underhang in MP (62%-78%) and ML (24%-34%) areas without difference. The anatomical tibial design had significant improvement for posteromedial coverage by about 69.8%-74.3% compared with the symmetrical designs. ConclusionRecently introduced anatomical tibial design improves surface coverage at the medioposterior dimension in Asian knees. Moreover, there is small improvement in ML fit compared with the symmetrical designs.

Patellar component design influences size selection and coverage

BackgroundPatellofemoral (PF) complications following total knee arthroplasty continue to occur. Outcomes are influenced by implant design, size and alignment in addition to patient factors. The objective of this study was to assess the effect of implant design, specifically round versus oval dome patellar components, on size selected and bony coverage in a population of 100 patients. MethodsIntraoperative assessments of patella component size were performed using surgical guides for round and oval designs. Digital images of the resected patellae with and without guides were calibrated and analyzed to measure bony coverage. Lastly, the medial–lateral location of the median ridge was assessed in the native patella and compared to the positioning of the apex of the patellar implants. ResultsIn 82% of subjects, a larger oval implant was selected compared to a round. Modest, but statistically significant, differences were observed in selected component coverage of the resected patella: 82.7% for oval versus 80.9% for round. Further, positioning of the apex of oval patellar components reproduced the median ridge of the native patella more consistently than for round components. ConclusionsThese findings characterized how implant design influenced size selection and coverage in a population of patients. The ability to “upsize” with oval dome components led to increases in bony coverage and better replication of the median ridge compared to round components. Quantifying the interactions between implant design, sizing and coverage for a current implant system in a population of patients supports surgical decision-making and informs the design of future implants.

IMAGING ANALYSIS OF ACETABULAR CUP POSITIONS IN TOTAL HIP ARTHROPLASTY FOR ADULTS WITH ACETABULAR DYSPLASIA

To investigate the influence of the degree of acetabular deformity and the learning-curve on the acetabular cup positions in total hip arthroplasty (THA) for adults with developmental dysplasia of hip (DDH). Between January 2008 and December 2015, 130 patients (144 hips) with DDH underwent primary THA, and the clinical data were analyzed retrospectively. Fifty-three patients (59 hips) were admitted before 2012, and 77 patients (85 hips) were treated after 2012. There were 32 males and 98 females, aged from 31 to 83 years (mean, 61). Unilateral replacement was performed in 116 cases and bilateral replacement in 14 cases. Of 144 hips, 48 hips were rated as Crowe type I, 57 hips as type II, and 39 hips as type of III/IV. The standard pelvic radiograph was taken within 1 week after operation. The mediCAD software was adopted to measure the angle of anteversion and abduction, bony coverage, and the distance between true rotating center and optimal rotating center to the connection of teardrops and the horizontal distance between two centers to evaluate the qualified rate of acetabular cup positions. Compared with the patients with the same type in 2013-2015 group, the anteversion angle and qualified rate of acetabular cup position significantly decreased in patients with Crowe I (P<0.05); the horizontal distance significantly increased and qualified rate of acetabular cup position significantly decreased in patients with Crowe II (P<0.05); and the anteversion angle significantly decreased and the horizontal distance significantly increased in patients with Crowe III/IV (P<0.05) in 2008-2012 group. But no significant difference was shown in the other indexes (P>0.05). In all Crowe types, the vertical distance between the true rotating center and the optimal rotating center increased with the degree of acetabular deformity in both 2008-2012 group and 2013-2015 group, showing significant difference (P<0.05), but no significant difference was found in the other indexes (P>0.05). For adults with acetabular dysplasia, there are high potential risks for unsatisfactory acetabular cup positions during primary THA. So it is necessary to evaluate acetabular deformities and to sum up operative experience so as to improve the accuracy of cups installation.

Lateral acetabular coverage as a predictor of femoroacetabular cartilage thickness.

To investigate the correlation between femoroacetabular cartilage thickness and lateral acetabular coverage in patients undergoing hip arthroscopy for a variety of indications. Articular cartilage at the hip is hypothesized to undergo adaptive change secondary to unique patterns of pathomechanical loading which results in a direct relationship between acetabular coverage and femoroacetabular cartilage thickness. A cohort of 252 patients presenting to our dedicated hip preservation service between June 2013 and June 2015 were retrospectively analysed. Preoperative radiographs and MRI studies were obtained for all symptomatic hips and classified according to radiographic lateral center edge angle (LCEA) as follows: normal acetabular coverage (25–40°), acetabular overcoverage (≥40°), borderline dysplasia (20–24.9°) and frank dysplasia (<20°). Femoroacetabular cartilage thickness was measured on a preoperative MRI-scan at the fovea, middle sourcil, and lateral sourcil. In all groups, cartilage thickness was maximized at the lateral sourcil relative to the middle sourcil or fovea (P < 0.001). Furthermore, articular cartilage thickness was significantly increased when comparing one group to successive groups with diminished lateral acetabular coverage. Indeed, multivariate analyses confirmed LCEA to be the strongest determinant of femoroacetabular cartilage thickness compared with age, gender, body-mass index or presence of cam/pincer lesions. Patients with borderline and frank dysplasia exhibit increased values of femoroacetabular cartilage thickness in the weight-bearing zone, potentially indicating a compensatory reaction to the lack of bony coverage. Articular cartilage thickness may serve as an instability marker and inform clinical decision-making for patients with borderline dysplasia.

Magnetic resonance imaging evaluation of acetabular orientation in normal Chinese children.

There are no data regarding the acetabular orientation on magnetic resonance imaging (MRI); this study investigates the changes of acetabular orientation with age in normal Chinese children.We retrospectively analyzed the medical records of children who underwent hip MRI examination at our hospital from January 2009 to December 2015. A total of 180 patients with normal MRI reading of the hip joints were included and were divided into 14 groups according to age: from 6 months of age and then for each year from 1 to 16 years. The bony and cartilage acetabular anteversion angle (AAA), acetabular inclination angle (AIA), and acetabular index (AI) were measured. Total bony and cartilage femoral head coverage angles were measured on axial section total femoral head coverage angle (a-TCA) and coronal section total femoral head coverage angle (c-TCA).The mean bony AAA and AIA were 12.2 ± 2.5° and 50.9 ± 2.5°, respectively; both of them stayed constant from the age of 6 months to 16 years. Similar results were found in cartilage AAA (12.1 ± 2.5°) and AIA (41.2 ± 3.0°). There was no difference between bony and cartilage AAA, but bony AIA was significantly larger than cartilage AIA. Bony AI was 24.1 ± 2.4° at the age of 6 months, decreasing to 12.5 ± 2.3° by 12 to 13 years of age; cartilage AI (5.9 ± 1.7°) maintained a steady value with age. The mean bony a-TCA and c-TCA at 6 months were 117.0 ± 5.8° and 127.5 ± 5.1°, increasing to 144.5 ± 4.6° and 140.7 ± 2.5° at the age of 16 years. However, the cartilage a-TCA (145.2 ± 7.2°) and c-TCA (154.1 ± 5.7°) did not change significantly with age.Both bony and cartilage AAA and AIA remain constant up to the age of 16 years in normal Chinese pediatric population. Although the cartilage coverage of femoral head by the acetabulum remains unchanged with age, the bony coverage of femoral head increases.

Effect of Acetabular Component Positioning on Functional Outcomes in Primary Total Hip Arthroplasty

BackgroundAcetabular component positioning is crucial to a successful total hip arthroplasty (THA). This study evaluated the effect of absolute acetabular component position as well as acetabular position relative to bony anatomy on patient-reported functional outcomes after primary THA. MethodsPrimary, press fit, hemispherical metal-on-polyethylene THA performed between 2003 and 2011 were analyzed. Western Ontario and McMaster Osteoarthritis Index (WOMAC), Harris Hip Score (HHS), Short Form-12 scores, and radiographs between 2 and 3 years after the index procedure were assessed. ResultsOf the 1241 primary THA included, the mean abduction and anteversion angles were 44.4 ± 6.94 and 21.7 ± 11.9 degrees, respectively. The mean anterior and lateral overhang were 1.9 ± 3.6 and 2.5 ± 3.4 mm, respectively. There was no correlation between functional outcomes and acetabular inclination. A weak positive correlation between anteversion and HHS (P < .001) and WOMAC (P = .02) scores was found. For relative position, anterior overhang of the acetabular component beyond the bone resulted in inferior Short Form-12 physical function (P = .001), HHS (P = .004), and WOMAC (P < .001) scores compared to those with bony coverage. Mean HHS pain score was 41.20 ± 5.69 in patients with lateral overhang and 41.97 ± 5.04 in those who had bony coverage of the lateral edge of the acetabular component (P = .02). ConclusionThe tribology and biomechanics of acetabular component position have been extensively studied without examination of how it affects patient function. Although statistical significance was seen, clinical outcome scores were not sensitive enough to show a clinically significant effect of the absolute or relative position of the acetabular component.

Lateral Acetabular Coverage Predicts the Size of the Hip Labrum

Background: Bony morphological abnormalities of the hip joint are often accompanied by adaptive soft tissue changes. These adaptive changes, if better understood and characterized, may serve to inform clinical decision making. Purpose: To investigate the correlation between the size of the hip labrum and lateral acetabular coverage in patients at our hip preservation clinic. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A cohort of 236 patients seen at a dedicated hip preservation service between June 2013 and June 2015 were retrospectively analyzed. Patients were grouped according to the degree of acetabular coverage, as measured by the lateral center-edge angle (LCEA): normal acetabular coverage (25°-39.9°), acetabular overcoverage (≥40°), borderline dysplasia (20°-24.9°), and frank dysplasia (<20°). Preoperative magnetic resonance imaging was utilized to measure the length of the labrum at 3 locations: laterally, anteriorly, and anteroinferiorly. Results: Frankly dysplastic and borderline dysplastic hips exhibited larger values of labral length at all locations when compared with hips with normal acetabular coverage (P < .001) or acetabular overcoverage (P < .001). Interestingly, mean labral length values in frank dysplasia were statistically similar to corresponding measurements in borderline dysplasia. In hips with frank dysplasia, borderline dysplasia, or normal acetabular coverage, labral length was consistently greatest at the lateral labrum and correspondingly lowest at the anteroinferior labrum (P < .001). In hips with acetabular overcoverage, labral length did not vary significantly between the lateral, anterior, and anteroinferior locations. Multivariate analyses confirmed LCEA to be the strongest predictor of labral length, irrespective of measurement location. Conclusion: Patients with borderline dysplasia and frank dysplasia exhibited increased values of labral length in the weightbearing zone, potentially indicating a compensatory reaction to the lack of bony coverage. Labral length may serve as an instability marker and inform clinical decision making for patients with borderline dysplasia.