Aims. To evaluate how abnormal proximal femoral anatomy affects different femoral version measurements in young patients with hip pain. Methods. First, femoral version was measured in 50 hips of symptomatic consecutively selected patients with hip pain (mean age 20 years (SD 6), 60% (n = 25) females) on preoperative CT scans using different measurement methods: Lee et al, Reikerås et al, Tomczak et al, and Murphy et al. Neck-shaft angle (NSA) and α angle were measured on coronal and radial CT images. Second, CT scans from three patients with femoral retroversion, normal femoral version, and anteversion were used to create 3D femur models, which were manipulated to generate models with different NSAs and different cam lesions, resulting in eight models per patient. Femoral version measurements were repeated on manipulated femora. Results. Comparing the different measurement methods for femoral version resulted in a maximum mean difference of 18° (95% CI 16 to 20) between the most proximal (Lee et al) and most distal (Murphy et al) methods. Higher differences in proximal and distal femoral version measurement techniques were seen in femora with greater femoral version (r > 0.46; p < 0.001) and greater NSA (r > 0.37; p = 0.008) between all measurement methods. In the parametric 3D manipulation analysis, differences in femoral version increased 11° and 9° in patients with high and normal femoral version, respectively, with increasing NSA (110° to 150°). Conclusion. Measurement of femoral version angles differ depending on the method used to almost 20°, which is in the range of the aimed surgical correction in derotational femoral osteotomy and thus can be considered clinically relevant. Differences between proximal and distal measurement methods further increase by increasing femoral version and NSA. Measurement methods that take the entire proximal femur into account by using distal landmarks may produce more sensitive measurements of these differences. Cite this article: Bone Jt Open 2022;3(10):759–766

Introduction. Accurate component placement in total hip arthroplasty (THA) improves post-operative stability and reduces wear and aseptic loosening. Methods for achieving accurate stem placement have not been as extensively studied as cup placement. Objectives. The purpose of this study is to determine how consistently femoral stem version can be corrected to an ideal of 15 +/− 5 degrees using robotic guidance. Furthermore, the study aims to identify other factors related to approach and patient demographics, which may influence the degree of correction obtained. Methods. 175 consecutive patients who underwent MAKO robotic guidance THA were included in the study with a mean age of 57.9 years and a mean body mass index (BMI) of 30.41kg/m2. 48% of the population was male and 74% of the procedures were performed through an anterior approach. The absolute difference between 15 degrees of anteversion and native femoral version as well as 15 degrees of anteversion and femoral stem version was calculated for each patient. A smaller absolute value post-operatively reflects a closer femoral stem version to a target of 15 degrees. Results. The mean native femoral version was 6.39+/−9.14 degrees. The mean stem version was 9.23+/−8.57 degrees. With respect to achieving a target version of 15 degrees the mean absolute difference between native version and 15 degrees was 10.46+/−6.94 degrees and mean absolute difference between the stem version and 15 degrees was 8.37+/−6.03 degrees. This difference was statistically significant. 69% of patients were able to have their native femoral version corrected to a target of 15 degrees. Conclusions. Robotic guidance in THA was effective in correcting native femoral version towards a target of 15 degrees. This is can be achieved using both the anterior and posterior approach and is not affected by BMI

Adult hip dysplasia AHD is a complex 3D pathology of lateral coverage, version and/or volume and is often associated with increased femoral anteversion. The Mckibbin index MI is the combination of acetabular version AV and femoral version FV and is used as a measure of anterior hip Stability/ Impingement(1). The Bernese Periacetabular osteotomy PAO is a powerful tool in treating AHD, but it does not address FV. De-rotational femoral osteotomies FO increases risk of complications, operative time and might condemn the patient to Secondary osteotomies to balance the gait. We aim to investigate the effect of MI and FV on PROMs in patients undergoing PAO only. 593 PAOs identified on the Local Hip preservation registry between 01/2013 and 7/2023. PAOs for retroversion, residual Perthes and those combined with FO were excluded. Patients with no available PROMS at 2 years were excluded. Independent variables were collected from E-notes and imaging including MI and FV. A multiple linear regression analysis was performed against preoperative iHot12, and iHot12 change at 2years. The mean FV was 18.86± 12.4 SD. Mean MI was 36.07, SD 15.36. Mean preop iHot12 score was 29.83 ± 17.38 SD. Mean change in iHot12 at 2 years was+36.47 ± 28.44 SD. Females and a higher BMI were statistically correlated to a lower preoperative iHot12. A lower preop iHot12 score and a higher preop AI were correlated to a bigger change in iHot12 at 2years with statistical significance. MI and FV were not found to have a statistically significant correlation with Outcome measures,. An increased Mckibbin index and femoral anteversion were not correlated with worse outcomes at two years. PAO alone in the presence of increased femoral anteversion avoids risks associated with FO which can be performed later if required

Introduction

Appropriate femoral stem anteversion is an important factor in maintaining stability and maximizing the performance of the bearing after total hip replacement (THR). The anteversion of the native femoral neck has been shown to have a significant effect on the final anteversion of the stem, particularly with a uncemented femoral component. The aim of this study was to quantify the variation in native femoral neck anteversion in a population of patients requiring total hip replacement.

Introduction

Appropriate prosthetic alignment is an important factor in maintaining stability and maximising the performance of the bearing after total hip replacement (THR). With a cementless component, the anteversion of the native femur has been shown to influence the anteversion of the prosthetic stem. However, the extent to which anteversion of a cementless stem can be adjusted from the native anteversion has seldom been reported. The aim of this study was to investigate the difference between native and stem anteversion with two different cementless stem designs.

Combined anteversion angle of acetabular component and femeral neck is an important factor for total hip arthroplasty (THA) as it may affect impingement and dislocation. Previous studies have collected data mainly from direct measurements of bone morphology or manual measurements from 2D or 3D radiolographic images. The purpose of this study was to electronically measure the version angles in native acetabulum and femur in matured normal Caucasion population using a novel virtual bone database and analysis environment named SOMA™.

221 CT scans from a skeletally mature, normal Caucasian population with an age range of 30–95 years old. The population included 135 males and 86 females. CT data was converted to virtual bones with cortical and cancellous boundaries using custom CT analytical sofware. (SOMA™ V.3.2) Auxillary reference frames were constructed and measurements were performed within the SOMA™ design environment. Acetabular Anteversion (AA) angle as defined by Murray¹ was measured. The acetabular rim plane was constructed by selecting 3 bony land marks from pubis, ilium and ischium. A vector through acetabular center point and normal to the rim plane defined the plane for the AA measurement. The AA was defined as the angle of this plane relative to the frontal (Coronal) plane of the pelvis. The Femoral Neck Anteversion (FNA) angle was measured from the neck axis plane to the frontal (Coronal) plane as defined by the posterior condyles. The neck axis plane was constructed to pass through femoral neck axis perpendicular to the transverse plane. The combined anteversion angle was computed as the summation of acetabular and femoral anteversion angles. Student's t tests were performed to compare gender difference with an assumed 95% confidence level.

The mean AA angle for total population was 25.8°, SD=7.95°. The mean AA for male was 24.8°, SD=5.93° and for female was 27.3°, SD=7.14°. P=0.009.

The mean FNA angle for total population was 14.3°, SD=6.52°. The mean FNA for male was 13.5°, SD=7.97° and for female was 15.5°, SD=7.80°. P=0.058.

The mean combined anteversion angle for total population was 40.1°, SD=10.76°. The mean combined anteversion angle for male was 38.3° SD=10.39 ° and for female was 42.8° SD=10.83 °. P=.0002. The plot of AA as a function of FNA shows weak correlation for both male and female. (Figure 1) The frequency distribution is shown in Figure 2.

The results showed the both AA, FNA and combined anteversion angles were significantly smaller in male population than that in female population. The FNA angle of the cementless femoral stem can be smaller than with the natural femur, therefore a higher AA or higher posterior build up may be required for the acetabular component for optimal function of a THA.

Aims. Periacetabular osteotomy (PAO) is an established treatment for acetabular dysplasia. It has also been proposed as a treatment for patients with acetabular retroversion. By reviewing a large cohort, we aimed to test whether outcome is equivalent for both types of morphology and identify factors that influenced outcome. Methods. A single-centre, retrospective cohort study was performed on patients with acetabular retroversion treated with PAO (n = 62 hips). Acetabular retroversion was diagnosed clinically and radiologically (presence of a crossover sign, posterior wall sign, lateral centre-edge angle (LCEA) between 20° and 35°). Outcomes were compared with a control group of patients undergoing PAO for dysplasia (LCEA < 20°; n = 86 hips). Femoral version was recorded. Patient-reported outcome measures (PROMs), complications, and reoperation rates were measured. Results. The mean Non-Arthritic Hip Score (NAHS) preoperatively was 58.6 (SD 16.1) for the dysplastic hips and 52.5 (SD 12.7) for the retroverted hips (p = 0.145). Postoperatively, mean NAHS was 83.0 (SD 16.9) and 76.7 (SD 17.9) for dysplastic and retroverted hips respectively (p = 0.041). Difference between pre- and postoperative NAHS was slightly lower in the retroverted hips (18.3 (SD 22.1)) compared to the dysplastic hips (25.2 (SD 15.2); p = 0.230). At mean 3.5 years’ follow-up (SD 1.9), one hip needed a revision PAO and no hips were converted to total hip arthroplasty (THA) in the retroversion group. In the control group, six hips (7.0%) were revised to THA. No differences in complications (p = 0.106) or in reoperation rate (p = 0.087) were seen. Negative predictors of outcome for patients undergoing surgery for retroversion were female sex, obesity, hypermobility, and severely decreased femoral anteversion. Conclusion. A PAO is an effective surgical intervention for acetabular retroversion and produces similar improvements when used to treat dysplasia. Femoral version should be routinely assessed in these patients and when extremely low (< 0°), as an additional procedure to address this abnormality may be necessary. Females with signs of hypermobility should also be consulted of the likely guarded improvement. Cite this article: Bone Jt Open 2021;2(9):757–764

Aims. Research on hip biomechanics has analyzed femoroacetabular contact pressures and forces in distinct hip conditions, with different procedures, and used diverse loading and testing conditions. The aim of this scoping review was to identify and summarize the available evidence in the literature for hip contact pressures and force in cadaver and in vivo studies, and how joint loading, labral status, and femoral and acetabular morphology can affect these biomechanical parameters. Methods. We used the PRISMA extension for scoping reviews for this literature search in three databases. After screening, 16 studies were included for the final analysis. Results. The studies assessed different hip conditions like labrum status, the biomechanical effect of the cam, femoral version, acetabular coverage, and the effect of rim trimming. The testing and loading conditions were also quite diverse, and this disparity limits direct comparisons between the different researches. With normal anatomy the mean contact pressures ranged from 1.54 to 4.4 MPa, and the average peak contact pressures ranged from 2 to 9.3 MPa. Labral tear or resection showed an increase in contact pressures that diminished after repair or reconstruction of the labrum. Complete cam resection also decreased the contact pressure, and acetabular rim resection of 6 mm increased the contact pressure at the acetabular base. Conclusion. To date there is no standardized methodology to access hip contact biomechanics in hip arthroscopy, or with the preservation of the periarticular soft-tissues. A tendency towards improved biomechanics (lower contact pressures) was seen with labral repair and reconstruction techniques as well as with cam correction. Cite this article: Bone Joint Res 2023;12(12):712–721

Abstract. Purpose The aim of this study was investigate the relationship between version and torsional abnormalities of the acetabulum, femur and tibia in patients with symptomatic FAI. Methods A systematic review was performed according to PRISMA guidelines using the EMBASE, MEDLINE, PubMed and Cochrane databases. Original research articles evaluating the described version and torsional parameters in FAI were included. The MINORS criteria was used to appraise study quality and risk of bias. Mean version and torsion values were displayed using forest plot and the estimated proportion of hips displaying abnormalities in version/torsion were calculated. Results. A total of 1206 articles were identified from the initial search, with 43 articles, involving 8,861 hips, meeting the inclusion criteria. All studies evaluating femoral or acetabular version in FAI reported ‘normal’ mean version values (10. 0. to 25. 0. ). However, distribution analysis revealed that an estimated 31% and 51% of patients with FAI displayed abnormal central acetabular and femoral version respectively. Conclusion. Up to 51% of patients presenting with symptomatic FAI show an abnormal femoral version, whilst up to 31% demonstrate abnormal acetabular version. This high percentage of version abnormalities highlights the importance of evaluating these parameters routinely during assessment of patients with FAI, in order to guide clinical decision making

Aims. The frequency of severe femoral retroversion is unclear in patients with femoroacetabular impingement (FAI). This study aimed to investigate mean femoral version (FV), the frequency of absolute femoral retroversion, and the combination of decreased FV and acetabular retroversion (AR) in symptomatic patients with FAI subtypes. Methods. A retrospective institutional review board-approved observational study was performed with 333 symptomatic patients (384 hips) with hip pain due to FAI evaluated for hip preservation surgery. Overall, 142 patients (165 hips) had cam-type FAI, while 118 patients (137 hips) had mixed-type FAI. The allocation to each subgroup was based on reference values calculated on anteroposterior radiographs. CT/MRI-based measurement of FV (Murphy method) and AV were retrospectively compared among five FAI subgroups. Frequency of decreased FV < 10°, severely decreased FV < 5°, and absolute femoral retroversion (FV < 0°) was analyzed. Results. A significantly (p < 0.001) lower mean FV was found in patients with cam-type FAI (15° (SD 10°)), and in patients with mixed-type FAI (17° (SD 11°)) compared to severe over-coverage (20° (SD 12°). Frequency of decreased FV < 10° was significantly (p < 0.001) higher in patients with cam-type FAI (28%, 46 hips) and in patients with over-coverage (29%, 11 hips) compared to severe over-coverage (12%, 5 hips). Absolute femoral retroversion (FV < 0°) was found in 13% (5 hips) of patients with over-coverage, 6% (10 hips) of patients with cam-type FAI, and 5% (7 hips) of patients with mixed-type FAI. The frequency of decreased FV< 10° combined with acetabular retroversion (AV < 10°) was 6% (8 hips) in patients with mixed-type FAI and 5% (20 hips) in all FAI patients. Of patients with over-coverage, 11% (4 hips) had decreased FV < 10° combined with acetabular retroversion (AV < 10°). Conclusion. Patients with cam-type FAI had a considerable proportion (28%) of decreased FV < 10° and 6% had absolute femoral retroversion (FV < 0°), even more for patients with pincer-type FAI due to over-coverage (29% and 13%). This could be important for patients evaluated for open hip preservation surgery or hip arthroscopy, and each patient requires careful personalized evaluation. Cite this article: Bone Jt Open 2022;3(7):557–565

We have previously reported on the improved all-cause revision and improved revision for instability risk in lipped liner THAs using the NJR dataset. These findings corroborate studies from the Australian (AOANJRR) and New Zealand (NZOA) joint registries. The optimal orientation of the lip in THAs utilising a lipped liner remains unclear to many surgeons. The aim of this study was to identify impingement-free optimal liner orientations whilst considering femoral stem version, cup inclination and cup version. A cementless THA kinematic model was developed using a 20 degree XLPE liner. Physiological ROM and provocative dislocation manoeuvre analyses were performed. A total of 9 cup positions were analysed (inclination 30–40–50 degrees, anteversion 5-15-25 degrees) and combined with 3 stem positions (anteversion 0-15-30 degrees) and 5 lip orientations (right hip 11 to 7 o'clock). Some lip orientation/component position combinations lead to impingement within the physiological ROM range. Using a lipped liner increases the femoral head travel distance prior to dislocation when impingement occurs in the plane of the lip. In THAs with a cup inclination of 30 and 40 degrees, inferior lip orientations (7–8 o'clock for a right hip) performed best. Superior lip orientation performed best with a cup inclination of 50 degrees. Femoral stem version has a significant effect on the range of movement prior to impingement and hence the preferred lip orientation. The optimal orientation of the lip in lipped liner THA is dependent on the position of both the acetabular and femoral components. In the common component orientation combination of stem anteversion 15, cup inclination 40 and cup anteversion 15, the optimal lip orientation was postero-inferiorly (8 o'clock for a right hip). Preventing impingement during physiological ROM is possible with appropriate lip liner orientation

Introduction. Osteogenesis imperfect (OI) is a geno- and phenotypically heterogeneous group of congenital collagen disorders characterized by fragility and microfractures resulting in long bone deformities. OI can lead to progressive femoral coxa vara from bone and muscular imbalance and continuous microfracture about the proximal femur. If left untreated, patients develop Trendelenburg gait, leg length discrepancy, further stress fracture and acute fracture at the apex of the deformity, impingement and hip joint degeneration. In the OI patient, femoral coxa vara cannot be treated in isolation and consideration must be given to protecting the whole bone with the primary goal of verticalization and improved biomechanical stability to allow early loading, safe standing, re-orientation of the physis and avoidance of untreated sequelae. Implant constructs should therefore be designed to accommodate and protect the whole bone. The normal paediatric femoral neck shaft angle (FNSA) ranges from 135 to 145 degrees. In OI the progressive pathomechanical changes result in FNSA of significantly less than 120 degrees and decreased Hilgenreiner epiphyseal angles (HEA). Proximal femoral valgus osteotomy is considered the standard surgical treatment for coxa vara and multiple surgical techniques have been described, each with their associated complications. In this paper we present the novel technique of controlling femoral version and coronal alignment using a tubular plate and long bone protection with the use of teleoscoping rods. Methodology. After the decision to operate had been made, a CT scan of the femur was performed. A 1:1 scale 3D printed model (AXIAL3D, Belfast, UK) was made from the CT scan to allow for accurate implant templating and osteotomy planning. In all cases a subtrochanteric osteotomy was performed and fixed using a pre-bent 3.5 mm 1/3 tubular plate. The plate was bent to allow one end to be inserted into the proximal femur to act as a blade. A channel into the femoral neck was opened using a flat osteotome. The plate was then tapped into the femoral neck to the predetermined position. The final position needed to allow one of the plate holes to accommodate the growing rod. This had to be determined pre operatively using the 3D printed model and the implants. The femoral canal was reamed, and the growing rod was placed in the femur, passing through the hole in the plate to create a construct that could effectively protect both the femoral neck and the full length of the shaft. The distal part of the plate was then fixed to the shaft using eccentric screws around the nail to complete the construct. Results. Three children ages 5,8 and 13 underwent the procedure. Five coxa vara femurs have undergone this technique with follow-up out to 62 months (41–85 months) from surgery. Improvements in the femoral neck shaft angle (FNSA) were av. 18. o. (10–38. o. ) with pre-op coxa vara FNSA av. 99. o. (range 87–114. o. ) and final FNSA 117. o. (105–125. o. ). Hilgenreiner's epiphyseal angle was improved by av. 29. o. (2–58. o. ). However only one hip was restored to <25. o. In the initial technique employed for 3 hips, the plates were left short in the neck to avoid damaging the physis. This resulted in 2 of 3 hips fracturing through the femoral neck above the plate at approximately 1 year. There were revisions of the 3 hips to longer plates to prevent intra-capsular stress riser. All osteotomies united and both intracapsular fractures healed. No further fractures have occurred within the protected femurs and no other repeat operations have been required. Conclusions. Surgical correction of the OI coxa vara hip is complex. Bone mineral density, multiplanar deformity, a desire to maintain physeal growth and protection of the whole bone all play a role in the surgeon's decision making process. Following modifications, this technique demonstrates a novel method in planning and control of multiplanar proximal femoral deformity, resulting in restoration of the FNSA to a more appropriate anatomical alignment, preventing long bone fracture and improved femoral verticalization in the medium term follow-up

Clinical graphics allows creation of three dimensional simulation based on CT or MRI that allows pre-operative planning. The software reports several hip morphological parameters routinely. Our aim was to validate the measurements of acetabular morphological parameters using CT based clinical graphics in patients presenting with symptomatic hip pain. We reviewed standardised plain radiographs, CT scans and 3D clinical graphics outputs of 42 consecutive hips in 40 patients presenting with symptomatic hip pain. Acetabular index (AI), lateral centre edge angle (LCE), acetabular and femoral version measurements were analysed for the 3D clinical graphics with radiographs and CT as gold standard. Significant differences were noted in measurements of AI, LCE, acetabular version and femoral version using the 3D motion analysis versus conventional measures, with only acetabular version showing comparable measurements. Correlation between 3D clinical graphics and conventional measures of acetabular morphology (AI, LCE) showed only slight agreement (ICC <0.4); while substantial agreement was noted for acetabular and femoral version (IC > 0.5). Acetabular morphological parameters measured by 3D clinical graphics are not reliable or validated. While clinicians may pursue the use of 3D clinical graphics for preoperative non-invasive planning, caution should be exercised when interpreting the reports of hip morphological parameters such as AI and LCE

Introduction. The achieved anteversion of uncemented stems is to a large extent limited by the internal anatomy of the bone. A better understanding of this has recently become an unmet need because of the increased use of uncemented stems. We aimed to assess plan compliance in six degrees of freedom to evaluate the accuracy of PSI and guides for stem positioning in primary THAs. Materials and Methods. We prospectively collected 3D plans generated from preoperative CTs of 30 consecutive THAs (17 left and 13 right hips), in 29 patients with OA, consisting of 16 males and 13 females (median age 68 years, range 46–83 years). A single CT-based planning system and cementless type of implant were used. Post operatively, all patients had a CT scan which was reconstructed using state-of-the-art software solution: the plan and CT reconstruction models were. Outcome measures: 1) discrepancy between planned and achieved stem orientation angles Fig.2&3; 2) clinical outcome. Results. 1) The mean (±SD) discrepancy was low for: Varus-valgus −1.1 ± 1.4 deg (IQR −2.2 – 0.3 deg); Anterior-posterior 0.1 ± 1.6 deg (IQR −0.7 – 1.3 deg). The discrepancy was higher for femoral version −1.4 ± 8.2 deg (IQR −8.3 – 7.2 deg). 3D-CT planning correctly predicted sizes in 93% of the femoral components. 2) There was no intra-operative fracture, no case showed evidence of early periprosthetic osseous injury. Discussion. Surgeons and engineers should be cautious with their expectation of achieving the planned femoral stem version of an uncemented femoral stem from the pre-operative 3D-CT plan. Conclusion. This is the first study to 3D-mensionally evaluate 3D-printed patient-specific instrumentation and guides for achieved femoral stem component orientation vis-à-vis to the plan. The tools allow accurate implant orientation, however there is still potential for improvement. For any figures or tables, please contact the authors directly

Introduction: Femoroacetabular impingement (FAI) is one of the main causes of hip osteoarthritis. Femoral retroversion has been reported as a cause of FAI and it is well established that a retroverted femur produces hip pain and alterations in the external and internal rotation balance. However, no studies of femoral retroversion in patients with FAI have been reported. Furthermore, since the lack of internal rotation is a common feature in patients with FAI, it could be possible that femoral version abnormalities are present in these patients. The purpose of this study is to describe the femoral version in a group of patients with FAI and to assess its relation in the development of hip osteoarthritis. Methods: The history, x-rays and hip CT scans of 142 patients with FAI were reviewed. All patients presented persistent hip pain and were evaluated clinically between January 2006 and July 2008. We defined FAI when at least one of the following features were present:. an abnormal alpha angle (> 49°) measured on the elongated femoral neck x-ray,. a positive cross-over sign or pro-trusio acetabuli in the AP pelvis x-ray,. the presence of diminished anteversion in the femur (< 10°) or a retroverted femur (< 0°) in the CT scan, associated with a positive hip impingement test and lack of internal rotation at 90 degrees of flexion. We documented the type of FAI, the presence of acetabular dysplasia, coxa valga, coxa vara and the femoral version measured on the CT scan. The degree of osteoarthritis of the hip using the Tönnis classification was documented as well. Results: Two hundred and sixty-five FAI hips from 142 patients (73 females and 69 males) were analyzed. The average age was 36.7 years. The mean femoral version was 11.4 ° (−14.1° to 47°). We found 43 hips (16.6%) of the femora were retroverted and 133 hips (50%) had either diminished anteversion (< 10°) or were retroverted. In 12 hips (0.05%) the only cause of FAI was the presence of a diminished anteversion or retroverted femur. The statistical analysis using the generalized estimating equations method including the right and left hips, shown that among these six predictors, both femoral retroversion (p=0.046) and coxa vara (p< 0.001) were statistically significant for the presence of osteoarthritis. Conclusion: The presence of a retroverted femur seems to be a cofactor in the development of hip osteoarthritis in patients with FAI. The orthopedic surgeons should be aware of the high frequency of femoral retroversion when evaluating patients with hip impingement, in order to make the right diagnosis and treatment. It might be possible that this association between FAI and femoral retroversion is due to a common hip disease during skeletal maturation (i.e. SCFE) leading to two anatomical alterations at the proximal femur: reduced head-neck offset and retroverted femur

The purpose of this study was to investigate the influence of surgical approach on femoral stem version in THA. This was a retrospective database review of 830 THAs in 830 patients that had both preoperative and postoperative CT scans. All patients underwent staged bilateral THAs and received CT-based 3D planning on both sides. Stem version was measured in the second CT-scan and compared to the native neck axis measured in the first CT-scan, using the posterior condyles as the reference for both. Cases were performed by 104 surgeons using either a direct anterior (DAA, n=303) or posterior (PA, n=527) approach and one of four stem designs: quadrangular taper, calcar-guided short stem, flat taper and fit-and-fill. Sub-analyses investigated changes in version for low (≤5°), neutral (5–25°) and high (≥25°) native version subgroups and for the different implant types. Native version was not different between approaches (DAA = 12.6°, PA = 13.6°, p = 0.16). Overall, DAA stems were more anteverted relative to the native neck axis vs PA stems (5.9° vs 1.4°, p<0.001). This trend persisted in hips with high native version (3.2° vs -5.3°, p<0.01) and neutral native version (5.3° vs 1.3°, p<0.001), but did not reach significance in the low native version subgroup (8.9° vs 5.9°, p=0.13). Quadrangular taper, calcar-guided, and flat taper stem types had significantly more anteversion than native for DAA, while no differences were found for PA. Stems implanted with a direct anterior approach had more anteversion than those implanted with a posterior approach. The smaller surgical field, soft tissue tension and lack of a “tibial” vertical reference frame may contribute to this finding

Background: Blount’s original paper in 1937 described a case series of 28 patients with “Tibia Vara”. Since then various authors have attempted to describe in more detail the tibial and femoral deformities seen in this disease. It is still a poorly understood condition. This study describes the femoral rotational deformity that can occur in Blount’s disease. Methods: Over a 2 year period, all patients with Blount’s disease seen in the Orthopaedic department of a regional hospital in South Africa were entered into a database. They underwent a review of their notes, a clinical rotational profile of their lower limbs and a CT scan of the femoral head/neck and distal femur. From this database we performed a cross sectional study. We then compared our results both to previously published controls for hip rotation and anteversion angles and with respect to the rotational profile, to a small cohort of 32 “normal” local children. Results: A statistically significant increase in femoral anteversion in the affected legs was noted, with on average the femurs in Blount’s disease being 26 degrees more anteverted than previously published controls. A significant decrease in external rotation were also noted. Conclusions: Our results suggest that the marked intoeing seen in many cases of Blount’s disease may be caused by internal femoral version, in addition to the well recognized internal tibial version. This study highlights the following issues:. A rotational profile should be part of the routine clinical assessment of all Blount’s cases. A CT assessment of anteversion should be considered to quantify this accurately. Overcorrection of the tibial internal version (to correct the added femoral version/torsion) should be considered when doing tibial osteotomies in cases with marked femoral internal version. Some cases of Blount’s disease will require further correction of rotation, after corrective surgery around the knee, that included external rotation of the tibia. Persistent in-toeing may need a de-rotation osteotomy of the femur shaft

Introduction. Patellofemoral pain and instability can be quantified by using the tibial tuberosity to trochlea groove (TT-TG) distance with more than or equal to 20mm considered pathological requiring surgical correction. Aim of this study is to determine if knee joint rotation angle is predictive of a pathological TT-TG. Methods. One hundred limbs were imaged from the pelvis to the foot using Computer Tomography (CT) scans in 50 patients with patellofemoral pain and instability. The TT-TG distance, femoral version, tibial torsion and knee joint rotation angle ((KJRA) were measured. Limbs were separated into pathological and non-pathological TT-TG. Significant differences in the measured angles between the pathological and non-pathological groups were estimated using the t test. The inter- and intraobserver variability of the measurement was performed. Logistic regression analysis was used to find the best combination of rotational angle predictors for a pathological TT-TG. Results. The intraclass correlation coefficients for inter- and intraobserver variability of the measured parameters was higher than 0.94 for all measurements. A statistically significant difference (P=0.024) was found between the KJRA between the pathological (mean=10.6, SD=7.79 degrees) and the non-pathological group (mean=6.99, SD=5.06 degrees). Logistic regression analysis showed that both femoral version (P=0.03, OR = 0.95) and KJRA (P=0.004, OR=1.15) were, in combination, significant predictors of an abnormal TT-TG. Tibial torsion was not a significant predictor. Conclusion. The KJRA can be used as an alternative measurement when the TT-TG distance cannot be measured as in cases of severe trochlea dysplasia and may act as a surrogate for pathological TT-TG

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

Introduction: Although use of modular femoral components in revision hip arthroplasty is widely accepted, many still question the need for modular versatility in primary THA. The purpose of our study was to examine in a large cohort the percentage of hips in which femoral component version was changed to optimize stability or avoid prosthetic impingement of the THA construct. We hypothesized that the percentage of hips needing version change in routine primary THA would be low. Methods: This prospective study analyzed 1000 consecutive primary THAs using a modular S-ROM (DePuy) stem performed by 3 surgeons at 3 institutions all via a posterior approach. Mean patient age at surgery was 57.5 years; 51.6% were male. The difference in version between the femoral sleeve placed anatomically and the femoral stem was recorded intra-operatively. Results: Femoral component version was changed in 47.9% of hips. Logistic regression analysis showed no correlation between the likelihood of changing stem version and patient age (p=0.87), gender (p=0.23), diagnosis (p=0.54), or surgeon (p=0.27). 10 hips (1%) experienced early dislocation (within 3 months post-op). With the numbers available, there was a slight trend of lower dislocation rate in hips where stem version was changed (0.6%) versus those in which it was not (1.5%, p=0.16, chi squared). Conclusion: The incidence of femoral version change in routine primary THA was much higher than expected. It was difficult to predict the need to alter version based on clinical variables including diagnosis. Thus, we conclude it may be advantageous to routinely use a stem that allows variable version as it is not possible to pre-operatively determine when changing version will be required. In addition, we surmise our low dislocation rate compared to historical controls of THA performed using a posterior approach was aided by the ability to adjust version in almost half of our patients