Aims. The aim of this study was to determine whether there is a correlation between the grade of humeral osteoarthritis (OA) and the severity of glenoid morphology according to Walch. We hypothesized that there would be a correlation. Methods. Overal, 143 shoulders in 135 patients (73 females, 62 males) undergoing shoulder arthroplasty surgery for primary glenohumeral OA were included consecutively. Mean age was 69.3 years (47 to 85). Humeral head (HH), osteophyte length (OL), and morphology (transverse decentering of the apex, transverse, or coronal asphericity) on radiographs were correlated to the glenoid morphology according to Walch (A1, A2, B1, B2, B3), glenoid retroversion, and humeral subluxation on CT images. Results. Increased humeral OL correlated with a higher grade of glenoid morphology (A1-A2-B1-B2-B3) according to Walch (r = 0.672; p < 0.0001). It also correlated with glenoid retroversion (r = 0.707; p < 0.0001), and posterior humeral subluxation (r = 0.452; p < 0.0001). A higher humeral OL (odds ratio (OR) 1.17; 95% confidence interval (CI) 1.03 to 1.32; p = 0.013), posterior humeral subluxation (OR 1.11; 95% CI 1.01 to 1.22; p = 0.031), and glenoid retroversion (OR 1.48; 95% CI 1.30 to 1.68; p < 0.001) were independent factors for a higher glenoid morphology. More specifically, a humeral OL of ≥ 13 mm was indicative of eccentric glenoid types B2 and B3 (OR 14.20; 95% CI 5.96 to 33.85). Presence of an aspherical HH in the coronal plane was suggestive of glenoid types B2 and B3 (OR 3.34; 95% CI 1.67 to 6.68). Conclusion. The criteria of humeral OL and HH morphology are associated with increasing glenoid retroversion, posterior humeral subluxation, and eccentric glenoid wear. Therefore, humeral radiological parameters might hint at the morphology on the glenoid side. Cite this article: Bone Jt Open 2022;3(6):463–469

While cell morphology has been recognized as a fundamental regulator of cell behavior, few studies have measured the complex cell morphological changes of chondrocytes using quantitative cell morphometry descriptors in relation to inflammation and phenotypic outcome. Acute vs. persistent exposure to IL-1β and how IL-1β modulated dynamic changes in cell morphology in relation to the phenotype, donor and OA grade in healthy and osteoarthritis (OA) chondrocytes was investigated. A panel of quantitative cell morphometry descriptors was measured using an automated high-throughput method. Absolute quantification of gene expression was measured by ddPCR followed by correlation analyses. In OA chondrocytes, chronic IL-1β significantly decreased COL2A1, SOX9, and ACAN, increased IL-6 and IL-8 levels and caused chondrocytes to become less wide, smaller, longer, slimmer, less round and more circular, consistent with a de-differentiated phenotype. In healthy chondrocytes, 3 days after acute (72 h) IL-1β exposure, COL1A2 and IL-6 significantly increased but had minor effects on cell morphology. However, in healthy chondrocytes, persistent IL-1β led to more profound effects in all cell morphology descriptors and chondrocytes expressed significantly less COL2A1 and more IL-6 and IL-8 vs. controls and acutely-stimulated chondrocytes. In both OA and healthy chronically-stimulated chondrocytes, area, width and circularity were sensitive to the persistent presence of the IL-1β cytokine. Moreover, there were many significant and strong correlations among the measured parameters, with several indications of an IL-1β-mediated mechanism. Cell morphology combined with gene expression analysis could guide researchers interested in understanding inflammatory effects in the complex domain of cartilage/chondrocyte biology. Use of quantitative cell morphometry could complement classical approaches by providing numerical data on a large number of cells, thereby providing a biological fingerprint for describing chondrocyte phenotype, which could help to understand how changes in cell morphology lead to disease progression

Aims. The aim of this study was to investigate whether anterior pelvic plane-pelvic tilt (APP-PT) is associated with distinct hip pathomorphologies. We asked: is there a difference in APP-PT between young symptomatic patients being evaluated for joint preservation surgery and an asymptomatic control group? Does APP-PT vary among distinct acetabular and femoral pathomorphologies? And does APP-PT differ in symptomatic hips based on demographic factors?. Methods. This was an institutional review board-approved, single-centre, retrospective, case-control, comparative study, which included 388 symptomatic hips in 357 patients who presented to our tertiary centre for joint preservation between January 2011 and December 2015. Their mean age was 26 years (SD 2; 23 to 29) and 50% were female. They were allocated to 12 different morphological subgroups. The study group was compared with a control group of 20 asymptomatic hips in 20 patients. APP-PT was assessed in all patients based on supine anteroposterior pelvic radiographs using validated HipRecon software. Values in the two groups were compared using an independent-samples t-test. Multiple regression analysis was performed to examine the influences of diagnoses and demographic factors on APP-PT. The minimal clinically important difference (MCID) for APP-PT was defined as > 1 SD. Results. There were no significant differences in APP-PT between the control group and the overall group (1.1° (SD 3.0°; -4.9° to 5.9°) vs 1.8° (SD 3.4°; -6.9° to 13.2°); p = 0.323). Acetabular retroversion and overcoverage groups showed higher mean APP-PTs compared with the control group (p = 0.001 and p = 0.014) and were the only diagnoses with a significant influence on APP-PT in the stepwise multiple regression analysis. All differences were below the MCID. The age, sex, height, weight, and BMI showed no influence on APP-PT. Conclusion. APP-PT showed no radiologically significant variation across different pathomorphologies of the hip in patients being assessed for joint-preserving surgery. Cite this article: Bone Joint J 2024;106-B(5 Supple B):3–10

Reduced cervical spine canal AP diameter is linked to the development of spinal cord injury and myelopathy. This is of particular interest to clinicians in New Zealand, given a unique socio-ethnic make-up and prevalent participation in collision sport. Our study builds upon previous unpublished evidence, by analysing normal cervical spine CT scans to explore morphological differences in the sub-axial cervical spine canal, between New Zealand European, Māori and Paciāca individuals. 670 sub-axial cervical vertebrae (C3-C7) were analysed radiographically using high resolution CT trauma scans, showing no acute pathology with respect to the cervical spine. All measurements were made uPlising mulP-planar reconstruction software to obtain slices parallel to the superior endplate at each vertebral level. Maximal canal diameter was measured in the AP and transverse planes. Statistical analysis was performed using analysis of variance (ANOVA). We included 250 Maori, 250 NZ European and 170 Paciāca vertebrae (455 male, 215 female). Statistically and clinically signiācant differences were found in sagittal canal diameter between all ethnicities, at all spinal levels. NZ European vertebrae demonstrated the largest AP diameter and Paciāca the smallest, at all levels. Transverse canal diameter showed no signiācant difference between ethnicities, however the raatio of AP:transverse diameter was signiācantly different at all spinal levels except C3. Subjective morphological differences in the shape of the vertebral canal were noted, with Māori and Paciāca patients tending towards a flatter, curved canal shape. A previous study of 166 patients (Coldham, G. et al. 2006) found cervical canal AP diameter to be narrower in Māori and Paciāca patients than in NZ Europeans. Our study, evaluating the normal population, conārms these differences are likely reflecPve of genuine variation between these ethniciPes. Future research is required to critically evaluate the morphologic differences noted during this study

Acromial morphology has been implicated as a risk factor for unidirectional posterior shoulder instability. Studies utilising plain film radiographic landmarks have identified an increased risk of posterior shoulder dislocation in patients with higher acromion positioning. The aims of this study were to develop a reproducible method of measuring this relationship on cross sectional imaging and to evaluate acromial morphology in patients with and without unidirectional posterior shoulder instability. We analysed 24 patients with unidirectional posterior instability. These were sex and age matched with 61 patients with unidirectional anterior instability, as well as a control group of 76 patients with no instability. Sagittal T1 weighted MRI sequences were used to measure posterior acromial height relative to the scapular body axis (SBA) and long head of triceps insertion axis (LTI). Two observers measured each method for inter-observer reliability, and the intraclass correlation coefficient (ICC) calculated. LTI method showed good inter-observer reliability with an ICC of 0.79. The SBA method was not reproducible due suboptimal MRI sequences. Mean posterior acromial height was significantly greater in the posterior instability group (14.2mm) compared to the anterior instability group (7.7mm, p=0.0002) as well when compared with the control group (7.0mm, p<0.0001). A threshold of 7.5mm demonstrated a significant increase in the incidence of posterior shoulder instability (RR = 9.4). We conclude that increased posterior acromial height is significantly associated with posterior shoulder instability. This suggests that the acromion has a role as an osseous restraint to posterior shoulder instability

Abstract. Objective. A higher prevalence of cam morphology has been reported in the athletic population but the development of the cam morphology is not fully understood. The purpose of this systematic review is to establish the timing of development of the cam morphology in athletes, the proximal femoral morphologies associated with its development, and other associated factors. Methods. Embase, MEDLINE and the Cochrane Library were searched for articles related to development of the cam morphology, and PRISMA guidelines were followed. Data was pooled using random effects meta-analysis. Study quality was assessed using the Downs and Black criteria and evidence quality using the GRADE framework. Results. This search identified 16 articles involving 2,028 participants. In males, alpha angle was higher in athletes with closed physes than open physes (SMD 0.71; 95% CI 0.23, 1.19). Prevalence of cam morphology was associated with age during adolescence when measured per hip (β 0.055; 95% CI 0.020, 0.091) and per individual (β 0.049; 95% CI 0.034, 0.064). Lateral extension of the epiphysis was associated with an increased alpha angle (r 0.68; 95% CI 0.63, 0.73). A dose-response relationship was frequently reported between sporting frequency and cam morphology. There was a paucity of data regarding the development of cam morphology in females. Conclusions. Very low and low quality evidence suggests that in the majority of adolescent male athletes’ osseous cam morphology developed during skeletal immaturity, and that prevalence increases with age. Very low quality evidence suggests that osseous cam morphology development was related to lateral extension of the proximal femoral epiphysis

Abstract. Objectives. Osteoarthritis (OA) is a complex joint disorder characterised by the loss of extracellular matrix (ECM) leading to cartilage degeneration. Changes to cartilage cell (chondrocyte) behaviour occur including cell swelling, the development of fine cytoplasmic processes and cell clustering leading to changes in cell phenotype and development of focal areas of mechanically-weak fibrocartilaginous matrix. [1]. To study the sequence of events in more detail, we have investigated the changes to in situ chondrocytes within human cartilage which has been lightly scraped and then cultured with serum. Methods. Human femoral heads were obtained with Ethical permission and consent from four female patients (mean age 74 yrs) undergoing hip arthroplasty following femoral neck fracture. Osteochondral explants of macroscopically-normal cartilage were cultured as a non-scraped control, or scraped gently six times with a scalpel blade and both maintained in culture for up to 2wks in Dulbecco's Modified Eagle's Medium (DMEM) with 25% human serum (HS). Explants were then labelled with CMFDA (5-chloromethylfluorescein-diacetate) and PI (propidium iodide) (10μM each) to identify the morphology of living or dead chondrocytes respectively. Explants were imaged using confocal microscopy and in situ chondrocyte morphology, volume and clustering assessed quantitatively within standardised regions of interest (ROI) using Imaris. ®. imaging software. Results. Within 2wks of culture with HS, chondrocyte volume increased significantly from 412±9.3µm. 3. (unscraped) at day 0 to 724±16.6 µm. 3. (scraped) [N(n) = 4(380)] (P=0.0002). Chondrocyte clustering was a prominent feature of HS culture as the percentage of clusters in the cell population increased with scraping from 4.8±1.4% to 14.9±3.9% [N(n) = 4(999)] at week 2 (P=0.0116). In addition, the % of the chondrocyte population within clusters increased from approximately 38% to 60%, and the number of cells per cluster increased significantly from 3.2±0.08 to 4±0.22 (P=0.031). The development of abnormal ‘fibroblastic-like’ chondrocyte morphology demonstrating long (>5µm) cytoplasmic processes also occurred, however the time course of this was more variable. For some samples, clustering occurred before abnormal morphology, but for others the opposite occurred. Typically, by the second week, 17±2.64% of the cell population had processes and this increased to 22±4.02% [N(n) = 4(759)] with scraping. Conclusions. Scraping the cartilage will remove surface constituents including lubricants (e.g. lubricin, hyaluronic acid, phospholipids), extracellular matrix constituents (collagen, proteoglycans – potentially the ‘lamina splendens’) and cells (chondrocytes and mesenchymal stromal cells (MSCs)). Although we do not know which of these component(s) is important, the effect is to dramatically increase the permeation of serum factors into the cartilage matrix and signal the development of cytoplasmic processes, cell clustering and swelling. It is notable that these cellular changes are similar to those occurring in early OA. [1]. This raises the interesting possibility that scraped cartilage cultured with human serum recapitulates some of the changes to in situ chondrocytes during early stages of cartilage degeneration and as such, could be a useful model for following the deleterious changes to matrix metabolism. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Abstract. Background. Femoroacetabular impingement (FAI) has been extensively investigated and is strongly associated with athletic participation. The aim of this systematic review is to assess: the prevalence of cam-type FAI across various sports, whether kinematic variation between sports influences hip morphology, and whether performance level, duration and frequency of participation or other factors influence hip morphology in a sporting population. Methods. A systematic search of Embase, PubMed and the Cochrane Library was undertaken following PRISMA guidelines. The study was registered on the PROSPERO database (CRD4202018001). Prospective and retrospective case series, case reports and review articles published after 1999 were screened and those which met the inclusion criteria decided a priori were included for analysis. Results. The literature search identified 58 relevant articles involving 5,683 participants. Forty-nine articles described a higher prevalence of FAI across various ‘hip-heavy’ sports, including soccer, basketball, baseball, ice hockey, skiing, golf and ballet. In studies including non-athlete controls, a greater prevalence of FAI was reported in 66.7% of studies (n=8/12). The highest alpha angle was identified at the 1 o'clock position (n=9/9) in football, skiing, golf, ice hockey and basketball. Maximal alpha angle was found to be located in a more lateral position in goalkeepers versus positional players in ice hockey (1 o'clock vs 1.45 o'clock). A positive correlation was also identified between the alpha angle and both age and activity level (n=5/8 and n=2/3, respectively) and also between prevalence of FAI and both age and activity level (n=2/2 and n=4/5), respectively. Conclusions. Hip-heavy sports show an increased prevalence of FAI, with specific sporting activities influencing hip morphology. Both a longer duration and increased level of training also resulted in an increased prevalence of FAI

Abstract. OBJECTIVE. Flattening of the talar dome is observed clinically in haemarthropathy as structural and functional changes advance but has not been quantified yet. In order to confirm clinical observation, and assess the degree of change, morphological measurements were derived from MR images. METHODS. Four measurements were taken, using ImageJ (1.52v), from sagittal MRI projections at three locations – medial, lateral and central: Trochlear Tali Arc Length (TaAL), Talar Height (TaH), Trochlear Tali Length (TaL), and Trochlear Tali Radius (TaR). These measurements were used to generate three ratios of interest: TaR:TaAL, TaAL:TaL, and TaL:TaH. With the hypothesis of a flattening of the talar dome with haemarthropathy, it was expected that TaR:TaAL and TaL:TaH should be greater for haemophilic ankles, and TaAL:TaL should be smaller. A total of 126 MR images (ethics: MEEC 18–022) were included to assess the difference in those ratios between non-diseased ankles (33 images from 11 volunteers) and haemophilic ankles (93 images from 8 patients’ ankles). Non-diseased control measurements were compared to literature to assess the capacity of doing measurements on MRI instead of radiographs or CT. RESULTS. Reasonable agreement was found between measurements on non-diseased ankles and those from literature, with greatest variance in TaAL. The medial talus demonstrated decreases in all dimensions with haemophilia (TaR=2.4%, TaL=14.7%, TaAL=19.5% and TaH=27.8%; t-test at p<0.05), as did the lateral talus (TaR=6.2%, TaL=6.8%, TaAL=12.0% and TaH=22.4%; t-test at p<0.05). The effect on the central talus was not significant. TaAL:TaL showed talar flattening in the medial and lateral haemophilic talus (healthy medial=1.21, lateral=1.20; haemophilic medial=lateral=1.14). CONCLUSION. The results demonstrate non-uniform increased influence of haemarthropathy at the medial and lateral talar extremes, with relatively healthy measurements seen in the centre. The degree of morphological change is however progressive, differing with each haemophilic ankle. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

To investigate whether anterior pelvic plane-pelvic tilt (APP-PT) is associated with distinct hip pathomorphologies, we asked: (1) Is there a difference in APP-PT between symptomatic young patients eligible for joint preservation surgery and an asymptomatic control group? (2) Does APP-PT vary between distinct acetabular and femoral pathomorphologies? (3) Does APP-PT differ in symptomatic hips based on demographic factors?. IRB-approved, single-center, retrospective, case-control, comparative study in 388 symptomatic hips (357) patients (mean age 26 ± 2 years [range 23 to 29], 50% females) that presented to our tertiary center for joint preservation over a five year-period. Patients were allocated to 12 different morphologic subgroups. The overall study group was compared to a control group of 20 asymptomatic hips (20 patients). APP-PT was assessed in all patients based on AP pelvis X-rays using the validated HipRecon software. Values between overall and control group were compared using an independent samples t-test. Multiple regression analysis was performed to examine the influences of diagnoses and demographic factors on APP-PT. Minimal clinically important difference (MCID) of APP-PT was defined as >1 standard deviation. No significant differences in APP-PT between the control group and overall group (1.1 ± 3.0° [−4.9 to 5.9] vs 1.8 ± 3.4° [−6.9 to 13.2], p = 0.323) were observed. Acetabular retroversion and overcoverage groups showed higher APP-PT compared to the control group (both p < 0.05) and were the only diagnoses with significant influence on APP-PT in the stepwise multiple regression analysis. However, all observed differences were below the MCID. Demographic factors age, gender, height, weight and BMI showed no influence on APP-PT. APP-PT across different hip pathomorphologies showed no clinically significant variation. It does not appear to be a relevant contributing factor in the evaluation of young patients eligible for hip preservation surgery

Introduction. Traditionally, conventional radiographs of the hip are used to assist surgeons during the preoperative planning process, and these processes generally involve two-dimensional X-ray images with implant templates. Unfortunately, while this technique has been used for many years, it is very manual and can lead to inaccurate fits, such as “good” fits in the frontal view but misalignment in the sagittal view. In order to overcome such shortcomings, it is necessary to fully describe the morphology of the femur in three dimensions, therefore allowing the surgeon to successfully view and fit the components from all possible angles. Objective. The objective of this study was to efficiently describe the morphology of the proximal femur based on existing anatomical landmarks for use in surgical planning and/or forward solution modeling. Methods. Seven parameters are needed to fully define femoral morphology: head diameter, head center, neck shaft axis, femoral canal, proximal shaft axis, offset, and neck shaft angle. A previous algorithm has been developed in-house to automatically locate anatomical landmarks of patient specific bone models. Once the bone model has been aligned and scaled based on these landmarks, the femoral head diameter and center are calculated by iteratively fitting a sphere to the corresponding femoral head point cloud. An iterative cylindrical fitting algorithm is used to describe the neck shaft axis. The femoral canal is determined using three steps: 1) the femur is sliced at 10mm increments below the lesser trochanter, 2) the femoral canal boundary is determined at each slice, and 3) the largest circle is fit within each slice's canal boundary. The proximal shaft axis is described by fitting a line to the canal circle center locations. Offset is defined as the distance from the head center to the proximal shaft axis. Finally, the neck shaft angle is the angle between the neck shaft axis and the proximal shaft axis. Results. The goal pertaining to femoral component morphology is to provide meaningful information that can be used to determine how the femoral stem fits within the canal. Regardless of differences in bone sizes and geometries, the algorithm has proven to be successful in describing the femoral morphology of a patient-specific bone model. Discussion. These results lay the groundwork for an automatic stem fitting algorithm, which is described in a subsequent abstract. The morphology knowledge of the femoral head, femoral neck, femoral canal, and various axes can be coupled with known THA component parameters (such as offset, neck length, neck shaft angle, etc.) to allow our algorithms to predict the “best selection” and “best fit” for the femoral stem. This can also be applied to the acetabulum and can then be used as a surgical planning tool as well as a parameter when modeling postoperative predictions. For any figures or tables, please contact authors directly

Objectives. The spinopelvic relationship (including pelvic incidence) has been shown to influence pelvic orientation, but its potential association with femoroacetabular impingement has not been thoroughly explored. The purpose of this study was to prove the hypothesis that decreasing pelvic incidence is associated with increased risk of cam morphology. Methods. Two matching cohorts were created from a collection of cadaveric specimens with known pelvic incidences: 50 subjects with the highest pelvic incidence (all subjects > 60°) and 50 subjects with the lowest pelvic incidence (all subjects < 35°). Femoral version, acetabular version, and alpha angles were directly measured from each specimen bilaterally. Cam morphology was defined as alpha angle > 55°. Differences between the two cohorts were analysed with a Student’s t-test and the difference in incidence of cam morphology was assessed using a chi-squared test. The significance level for all tests was set at p < 0.05. Results. Cam morphology was identified in 47/100 (47%) femurs in the cohort with pelvic incidence < 35° and in only 25/100 (25%) femurs in the cohort with pelvic incidence > 60° (p = 0.002). The mean alpha angle was also greater in the cohort with pelvic incidence < 35° (mean 53.7°, . sd. 10.7° versus mean 49.7°, . sd. 10.6°; p = 0.008). Conclusions. Decreased pelvic incidence is associated with development of cam morphology. We propose a novel theory wherein subjects with decreased pelvic incidence compensate during gait (to maintain optimal sagittal balance) through anterior pelvic tilt, creating artificial anterior acetabular overcoverage and recurrent impingement that increases risk for cam morphology. Cite this article: W. Z. Morris, C. A. Fowers, R. T. Yuh, J. J. Gebhart, M. J. Salata, R. W. Liu. Decreasing pelvic incidence is associated with greater risk of cam morphology. Bone Joint Res 2016;5:387–392. DOI: 10.1302/2046-3758.59.BJR-2016-0028.R1

While controversy remains as to the relative benefit of operative (OM) versus non-operative management (NOM) of Achilles tendon ruptures (ATR), few studies have examined the effect on high impact maneuvers such as jumping and hopping. The purpose of this study is to compare functional performance and musculotendinous morphology in patients following OM or NOM for acute ATR. Eligible patients were aged 18-65 years old with an ATR who underwent OM or NOM within three weeks of injury and were at least one-year post injury. Gastrocnemius muscle thickness and Achilles tendon length and thickness were assessed with ultrasound. Functional performance was examined with single-leg hop tests and isokinetic plantar strength at 60o/s and 120o/s. 24 participants completed testing (12/ group). Medial (OM: 2.2 ± 0.4 cm vs 1.9 ± 0.3 cm, NOM 2.15 ± 0.5 cm vs 1.7 ± 0.5 cm; p = 0.002) and lateral (OM 1.8 ± 0.3 cm vs 1.5 ± 0.4 cm, NOM 1.6 ± 0.4 cm vs 1.3 ± 0.5 cm; p = 0.008) gastrocnemius thickness were reduced on the affected limb. The Achilles tendon was longer (OM: 19.9 ± 2.2 cm vs 21.9 ± 1.6 cm; NOM: 19.0 ± 3.7 cm vs 21.4 ± 2.9 cm; p = 0.009) and thicker (OM: 0.48 ± 0.16 cm vs 1.24 ± 0.20 cm; NOM: 0.54 ± 0.08 cm vs 1.13 ± 0.23 cm; p < 0.001) on the affected limb with no differences between groups. Affected limb plantar flexion torque at 20o plantar flexion was reduced at 60o/s (OM: 55.6 ± 20.2 nm vs 47.8 ± 18.3 nm; NOM: 59.5 ± 27.5 nm vs 44.7 ± 21.0 nm; p = 0.06) and 120o/s (OM: 44.6 ± 17.9 nm vs 36.6 ± 15.0 nm; NOM: 48.6 ± 16.9 nm vs 35.8 ± 10.7 nm; p = 0.028) with no group effect. There was no difference in single leg hop performance. Achilles tendon length explained 31.6% (p = 0.003) and 18.0% (p = 0.025) of the variance in plantar flexion peak torque limb symmetry index (LSI) at 60o/s and 120o/s respectively. Tendon length explained 28.6% (p=0.006) and 9.5% (p = 0.087) of LSI when torque was measured at 20o plantar flexion at 60o/s and 120o/s respectively. Conversely, tendon length did not predict affected limb plantar flexion peak torque (nm), angle-specific torque at 20o plantar flexion (nm) and affected limb single leg hop distance (cm) or LSI (%). There was no difference in tendon length between treatment groups and deficits in gastrocnemius thickness and strength are persistent. Deficits in the plantar flexion strength LSI are partially explained by increased tendon length following Achilles tendon rupture, regardless of treatment strategy. Hop test performance is maintained and may be the result of compensatory movements at other joints despite persistent plantarflexion weakness

Aims. Morphological abnormalities are present in patients with developmental dysplasia of the hip (DDH). We studied and compared the pelvic anatomy and morphology between the affected hemipelvis with the unaffected side in patients with unilateral Crowe type IV DDH using 3D imaging and analysis. Methods. A total of 20 patients with unilateral Crowe-IV DDH were included in the study. The contralateral side was considered normal in all patients. A coordinate system based on the sacral base (SB) in a reconstructed pelvic model was established. The pelvic orientations (tilt, rotation, and obliquity) of the affected side were assessed by establishing a virtual anterior pelvic plane (APP). The bilateral coordinates of the anterior superior iliac spine (ASIS) and the centres of hip rotation were established, and parameters concerning size and volume were compared for both sides of the pelvis. Results. The ASIS on the dislocated side was located inferiorly and anteriorly compared to the healthy side (coordinates on the y-axis and z-axis; p = 0.001; p = 0.031). The centre of hip rotation on the dislocated side was located inferiorly and medially compared to the healthy side (coordinates on the x-axis and the y-axis; p < 0.001; p = 0.003). The affected hemipelvis tilted anteriorly in the sagittal plane (mean 8.05° (SD 3.57°)), anteriorly rotated in the transverse plane (mean 3.31° (SD 1.41°)), and tilted obliquely and caudally in the coronal plane (mean 2.04° (SD 0.81°)) relative to the healthy hemipelvis. The affected hemipelvis was significantly smaller in the length, width, height, and volume than the healthy counterpart. (p = 0.014; p = 0.009; p = 0.035; p = 0.002). Conclusion. Asymmetric abnormalities were identified on the affected hemipelvis in patients with the unilateral Crowe-IV DDH using 3D imaging techniques. Improved understanding of the morphological changes may influence the positioning of the acetabular component at THA. Acetabular component malpositioning errors caused by anterior tilt of the affected hemi pelvis and the abnormal position of the affected side centre of rotation should be considered by orthopaedic surgeons when undertaking THA in patients with Crowe-IV DDH. Cite this article: Bone Joint J 2020;102-B(10):1311–1318

Aim. To systematically review the literature and anatomical atlases on LM morphology. Methods. Relevant studies were searched in PubMed (Medline) and Science Direct. Anatomical atlases were retrieved from multiple university libraries and online. Included atlases and studies were assessed at five items: visuals present(y/n), quality of visuals(in-/sufficient), labelling of multifidus (y/n), clear description of region of interest(y/n), description of plane has been described(y/n). This risk of bias assessment tool was developed to assess the quality of description of anatomy, since existing risk of bias tables have only been developed to assess the methodology of studies. Results. In total 69 studies and 19 anatomical atlases were included. Studies. - 52 of 69 studies, LM was described as a superficial muscle at the levels L4 – S1. Others presented the LM as deep intrinsic muscle. - Most used methods: MRI, ultrasound imaging or drawings. - 32 of 69 studies scored a total of five points at the risk of bias assessment, which means low risk of bias. Anatomical atlases. - LM is shown as a deep intrinsic back muscle covered by the erector spinae and fascia thoracolumbalis. - Most anatomical atlases (8/19) had a score of four points at the risk of bias assessment. Conclusion. Anatomy atlases reported different LM morphology compared to anatomical studies. Even between studies, there appears to be inconsistent reporting in LM anatomy. Variation in research methods that are used for measuring LM morphology could influence variation in describing and presenting LM morphology. Standardization of research methodology is recommended in order to compare studies. No conflicts of interest. Sources of Funding: SIA RAAK-Publiek

We examined the morphology of mammalian hips asking whether evolution can explain the morphology of impingement in human hips. We describe two stereotypical mammalian hips, coxa recta and coxa rotunda. Coxa recta is characterised by a straight or aspherical section on the femoral head or head-neck junction. It is a sturdy hip seen mostly in runners and jumpers. Coxa rotunda has a round femoral head with ample head-neck offset, and is seen mostly in climbers and swimmers. Hominid evolution offers an explanation for the variants in hip morphology associated with impingement. The evolutionary conflict between upright gait and the birth of a large-brained fetus is expressed in the female pelvis and hip, and can explain pincer impingement in a coxa profunda. In the male hip, evolution can explain cam impingement in coxa recta as an adaptation for running

Aims. The purpose of this study was to explore the correlation between femoral torsion and morphology of the distal femoral condyle in patients with trochlear dysplasia and lateral patellar instability. Methods. A total of 90 patients (64 female, 26 male; mean age 22.1 years (SD 7.2)) with lateral patellar dislocation and trochlear dysplasia who were awaiting surgical treatment between January 2015 and June 2019 were retrospectively analyzed. All patients underwent CT scans of the lower limb to assess the femoral torsion and morphology of the distal femur. The femoral torsion at various levels was assessed using the a) femoral anteversion angle (FAA), b) proximal and distal anteversion angle, c) angle of the proximal femoral axis-anatomical epicondylar axis (PFA-AEA), and d) angle of the AEA–posterior condylar line (AEA-PCL). Representative measurements of distal condylar length were taken and parameters using the ratios of the bianterior condyle, biposterior condyle, bicondyle, anterolateral condyle, and anteromedial condyle were calculated and correlated with reference to the AEA, using the Pearson Correlation coefficient. Results. The femoral torsion had a strong correlation with distal condylar morphology. The FAA was significantly correlated with the ratio of the bianterior condyle (r = 0.355; p = 0.009), the AEA-PCL angle (r = 0.340; p = 0.001) and the ratio of the anterolateral condyle and lateral condyle (ALC-LC) (r = 0.309; p = 0.014). The PFA-AEA angle was also significantly correlated with the ratio of the bianterior condyle (r = 0.319; p = 0.008), the AEA-PCL angle (r = 0.231; p = 0.031), and the ratio of ALC-LC (r = 0.261; p = 0.034). In addition, the bianterior condyle ratio showed a significant correlation with the biposterior condyle ratio (r = -0.324; p = 0.027) and the AEA-PCL angle (r = 0.342; p = 0.021). Conclusion. Increased femoral torsion correlated with a prominent anterolateral condyle and a shorter posterolateral condyle compared with the medial condyle. The deformities of the anterior and posterior condyles are combined deformities rather than being isolated and individual deformities in patients with trochlear dysplasia and patella instability. Cite this article: Bone Joint J 2020;102-B(7):868–873

Aims. The aim of the present study was to answer the question whether curve morphology and location have an influence on rigid conservative treatment in patients with adolescent idiopathic scoliosis (AIS). Methods. We retrospectively analyzed AIS in 127 patients with single and double curves who had been treated with a Chêneau brace and physiotherapeutic specific exercises (B-PSE). The inclusion criteria were the presence of structural major curves ≥ 20° and < 50° (Risser stage 0 to 2) at the time when B-PSE was initiated. The patients were divided into two groups according to the outcome of treatment: failure (curve progression to ≥ 45° or surgery) and success (curve progression < 45° and no surgery). The main curve type (MCT), curve magnitude, and length (overall, above and below the apex), apical rotation, initial curve correction, flexibility, and derotation by the brace were compared between the two groups. Results. In univariate analysis treatment failure depended significantly on: 1) MCT (p = 0.008); 2) the apical rotation of the major curve before (p = 0.007) and during brace treatment (p < 0.001); 3) the initial and in-brace Cobb angles of the major (p = 0.001 and p < 0.001, respectively) and minor curves (p = 0.015 and p = 0.002); 4) major curve flexibility (p = 0.005) and the in-brace curve correction rates (major p = 0.008, minor p = 0.034); and 5) the length of the major curve (LoC) above (p < 0.001) and below (p = 0.002) the apex. Furthermore, MCT (p = 0.043, p = 0.129, and p = 0.017 in MCT comparisons), LoC (upper length p = 0.003, lower length p = 0.005), and in-brace Cobb angles (major p = 0.002, minor p = 0.027) were significant in binary logistic regression analysis. Conclusion. Curve size, location, and morphology were found to influence the outcome of rigid conservative treatment of AIS. These findings may improve future brace design and patient selection for conservative treatment. Cite this article: Bone Joint J 2021;103-B(2):373–381

Objectives. For patients with Developmental Dysplasia of the Hip (DDH) who progress to needing total joint arthroplasty it is important to understand the morphology of the femur when planning for and undertaking the surgery, as the surgery is often technically more challenging in patients with DDH on both the femoral and acetabular parts of the procedure. 1. The largest number of male DDH patients with degenerative joint disease previously assessed in a morphological study was 12. 2. In this computed tomography (CT) based morphological study we aimed to assess whether there were any differences in femoral morphology between male and female patients with developmental dysplasia undergoing total hip arthroplasty (THA) in a cohort of 49 male patients, matched to 49 female patients. Methods. This was a retrospective study of the pre-operative CT scans of all male patients with DDH who underwent THA at two hospitals in Japan between 2006–2017. Propensity score matching was used to match these patients with female patients in our database who had undergone THA during the same period, resulting in 49 male and 49 female patients being matched on age and Crowe classification. The femoral length, anteversion, neck-shaft angle, offset, canal-calcar ratio, canal flare index, lateral centre-edge angle, alpha angle and pelvic incidence were measured for each patient on their pre-operative CT scans. Results. Significant differences were found in femoral anteversion with a mean male anteversion of 22 ˚ (±14.2), compared to 30˚ (±15.5), in females (p=0.02, Confidence Interval (C.I.) 1.6 to 14.9, Figure 1), offset, with a mean male offset of 31 mm (±6.2), compared to 29 mm (±6.1) in females, (p=0.04, C.I: 0.2 to 4.8), and femoral length with a mean femoral length of 434 mm in males (±22.2), compared to 407 mm in females (±23.9), (p<0.001, C.I: 19.2 to 34.3, Figure 2). No significant differences between male and female patients were found for the other measurements. Discussion. This was the first study of this size assessing femoral morphology in male patients with DDH undergoing THA. Significant differences were found between male and female patients in femoral anteversion, length and offset. This should be taken into account when planning and performing THA in these patients. Based on the findings from this study, a more anteverted femoral neck can be expected at the time of surgery in a female patient with DDH undergoing total hip arthroplasty, compared to a male patient

In total knee arthroplasty (TKA) the implant design is one key factor for a proper functional restoration of the diseased knee. Therefore, detailed knowledge on the shape (morphology) is essential to guide the design process. In literature, the morphology has been extensively studied revealing differences, e.g. between ethnicity and gender. However, it is still unclear in which way gender-specific morphological differences are sexual dimorphism or explained by differences in size. The aim of this study was to investigate the morphology of the distal femur under gender-specific aspects for a large group of patients. Statistical analysis was used to reveal significant differences and subsequent correlation analysis to normalise the morphology. A dataset of n=363 segmented distal femoral bone surface reconstructions (229 female, 134 male) were randomly collected from a database of patients which underwent TKA. In total, 34 morphological features (distances, angles), quantifying the distal femoral geometry, were determined full automatically. Subsequently, graphs and descriptive statistics were used to check normality and gender-specific differences were analysed by calculating the 95% confidence intervals for women and men separately. Finally, significant differences were normalised by dividing each feature by appropriate distance measurements and confidence intervals were recalculated. Looking at the confidence 95% intervals, 6 of 34 features did not show any significant differences between genders. Remarkably, this primarily involves angular (relative) features whereas distance (absolute) measurements were mostly gender dependent. Then, we normalised all distance measurements and radii according to their direction of measurement: Features defined in medial/lateral (ML) direction were divided by the overall ML width and those following the anterior/posterior direction were normalised based on the overall AP length. The results demonstrated that gender-specific differences mostly disappear by using an adequate normalisation term. In conclusion, implant sizes (femoral components) should not be linearly scaled according to one dimension. Instead, ML and AP directions should be regarded separately (non-isotropic scaling). Taking this into consideration, gender- specific differences might be neglected