In an adult man the mean femoral anteversion angle measures approximately 15°, for which the reasons have never been fully elucidated. An assortment of simian and quadruped mammalian femora was therefore examined and the anteversion angles measured. A simple static mathematical model was then produced to explain the forces acting on the neck of the femur in the quadruped and in man. Femoral anteversion was present in all the simian and quadruped femora and ranged between 4° and 41°. It thus appears that man has retained this feature despite evolving from quadrupedal locomotion. Quadrupeds generally mobilise with their hips flexed forwards from the vertical; in this position, it is clear that anteversion gives biomechanical advantage against predominantly vertical forces. In man with mobilisation on vertical femora, the biomechanical advantage of anteversion is against forces acting mainly in the horizontal plane. This has implications in regard to the orientation of hip replacements

1. Sustained medial rotation of the hind limb in the immature rabbit produces femoral anteversion and acetabular dysplasia. 2. Sustained lateral rotation produces retroversion. 3. Splinting the hind limbs in the Lorenz position corrects both anteversion and retroversion. 4. The mechanism of the Lorenz position is discussed

Hip rotation in extension and flexion was studied in 23 patients with idiopathic intoeing gait. In extension all the hips had markedly increased medial rotation and limited lateral rotation, fulfilling the criteria of excessive femoral anteversion. In flexion, however, rotation varied widely; in one group of patients medial rotation remained greater than lateral, but in the second group lateral rotation was equal to or greater than medial. CT scans showed that the hips in the first group were significantly more anteverted than those in the second. Clearly measurement of hip rotation in extension alone does not provide a dependable indication of femoral anteversion in children with intoeing gait; rotation in flexion also needs to be measured

The calculation of femoral anteversion using a static ultrasound scanner has been compared with results obtained by computer tomographic (CT) scanning. Assuming the CT results to be accurate, the ultrasound method was frequently found to be unreliable

Aims

Although CT is considered the benchmark to measure femoral version, 3D biplanar radiography (hipEOS) has recently emerged as a possible alternative with reduced exposure to ionizing radiation and shorter examination time. The aim of our study was to evaluate femoral stem version in postoperative total hip arthroplasty (THA) patients and compare the accuracy of hipEOS to CT. We hypothesize that there will be no significant difference in calculated femoral stem version measurements between the two imaging methods.

A new radiological technique is presented in which serial axial radiographs of the patellofemoral joints are taken under conditions in which the muscles about the knee and hip are contracted in a manner similar to that during weight-bearing. A form of analysis has been developed whereby patellar rotation can be measured in two planes and femoral rotation about its long axis inferred. A population of asymptomatic adults and children was investigated in this way and their results (regarded as normal) compared with those in fifteen children with idiopathic chondromalacia patellae. In the normal child the femur rotates medially with the onset of muscle activity; by contrast the children with chondromalacia show a reversal of this mechanism

Stereoradiography with a base shift of the source of illumination was used to produce pairs of radiographs to be measured by stereophotogrammetric techniques. The direction of shift was parallel with the longitudinal axis of the body, so that each radiograph in the stereopair could be used for other clinical purposes. A base shift of 10 centimetres with a distance of 100 centimetres between the focus and the film gave acceptable value of stereoscopic parallax. The radiographs were measured using a Hilger and Watts medical stereometer. This method was checked with test specimens, namely an osteotomised pelvis in which one acetabulum could be rotated and an osteotomised femur in which the whole upper portion could be rotated against the shaft. Measurements made on the acetabulum and its radiographs showed a correlation coefficient of 0.9838 over the range 0 to 30 degrees of anteversion, with a mean error +2.54 degrees and a standard deviation of +/- 1.52 degrees (n = 21). For the femoral neck, over the range from 10 degrees of retroversion to 80 degrees of anteversion, the correlation coefficient was 0.9979, the mean error +2.46 and the standard deviation +/- 1.48 degrees (n = 30).

At least four ways have been described to determine femoral component rotation, and three ways to determine tibial component rotation in total knee replacement (TKR). Each method has its advocates and each has an influence on knee kinematics and the ultimate short and long term success of TKR. Of the four femoral component methods, the author prefers rotating the femoral component in flexion to that amount that establishes a stable symmetrical flexion gap. This judgement is made after the soft tissues of the knee have been balanced in extension.

Of the three tibial component methods, the author prefers rotating the tibial component into congruency with the established femoral component rotation with the knee is in extension. This yields a rotationally congruent articulation during weight-bearing and should minimise the torsional forces being transferred through a conforming tibial insert, which could lead to wear to the underside of the tibial polyethylene. Rotating platform components will compensate for any mal-rotation, but can still lead to pain if excessive tibial insert rotation causes soft-tissue impingement.

Cite this article: Bone Joint J 2013;95-B, Supple A:140–3.

The measurements of the angle of anteversion of the femoral neck by ultrasound scanning is described. The method was compared with direct measurement in 30 dried femora, and was then used in 18 normal volunteers and eight patients. The method is non-invasive, accurate and easily applicable. Findings in normal subjects included variation of the angle of anteversion from 10 to 34 degrees with a maximal difference between sides of six degrees. The expected rotational deformity of the femur was found in patients with unilateral intoeing.

Aims. The goal of the current systematic review was to assess the impact of implant placement accuracy on outcomes following total knee arthroplasty (TKA). Methods. A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the Ovid Medline, Embase, Cochrane Central, and Web of Science databases in order to assess the impact of the patient-reported outcomes measures (PROMs) and implant placement accuracy on outcomes following TKA. Studies assessing the impact of implant alignment, rotation, size, overhang, or condylar offset were included. Study quality was assessed, evidence was graded (one-star: no evidence, two-star: limited evidence, three-star: moderate evidence, four-star: strong evidence), and recommendations were made based on the available evidence. Results. A total of 49 studies were identified for inclusion. With respect to PROMs, there was two-star evidence in support of mechanical axis alignment (MAA), femorotibial angle (FTA), femoral coronal angle (FCA), tibial coronal angle (TCA), femoral sagittal angle (FSA), femoral rotation, tibial and combined rotation/mismatch, and implant size/overhang or offset on PROMs, and one-star evidence in support of tibial sagittal angle (TSA), impacting PROMs. With respect to survival, there was three- to four-star evidence in support FTA, FCA, TCA, and TSA, moderate evidence in support of femoral rotation, tibial and combined rotation/mismatch, and limited evidence in support of MAA, FSA, and implant size/overhang or offset impacting survival. Conclusion. Overall, there is limited evidence to suggest that PROMs are impacted by the accuracy of implant placement, and malalignment does not appear to be a significant driver of the observed high rates of patient dissatisfaction following TKA. However, FTA, FCA, TCA, TSA, and implant rotation demonstrate a moderate-strong relationship with implant survival. Efforts should be made to improve the accuracy of these parameters in order to improve TKA survival. Cite this article: Bone Joint J 2021;103-B(9):1449–1456

Aims. Guided growth has been used to treat coxa valga for cerebral palsy (CP) children. However, there has been no study on the optimal position of screw application. In this paper we have investigated the influence of screw position on the outcomes of guided growth. Methods. We retrospectively analyzed 61 hips in 32 CP children who underwent proximal femoral hemi epiphysiodesis between July 2012 and September 2017. The hips were divided into two groups according to the transphyseal position of the screw in the coronal plane: across medial quarter (Group 1) or middle quarter (Group 2) of the medial half of the physis. We compared pre- and postoperative radiographs in head-shaft angle (HSA), Reimer’s migration percentage (MP), acetabular index (AI), and femoral anteversion angle (FAVA), as well as incidences of the physis growing-off the screw within two years. Linear and Cox regression analysis were conducted to identify factors related to HSA correction and risk of the physis growing-off the screw. Results. A total of 37 hips in Group 1 and 24 hips in Group 2 were compared. Group 1 showed a more substantial decrease in the HSA (p = 0.003) and the MP (p = 0.032). Both groups had significant and similar improvements in the AI (p = 0.809) and the FAVA (p = 0.304). Group 1 presented a higher incidence of the physis growing-off the screw (p = 0.038). Results of the regression analysis indicated that the eccentricity of screw position correlated with HSA correction and increases the risk of the physis growing-off the screw. Conclusion. Guided growth is effective in improving coxa valga and excessive femoral anteversion in CP children. For younger children, despite compromised efficacy of varus correction, we recommend a more centered screw position, at least across the middle quarter of the medial physis, to avoid early revision. Cite this article: Bone Joint J 2020;102-B(9):1242–1247

Aims. We investigated changes in the axial alignment of the ipsilateral hip and knee after total hip arthroplasty (THA). . Patients and Methods. We reviewed 152 patients undergoing primary THA (163 hips; 22 hips in men, 141 hips in women) without a pre-operative flexion contracture. The mean age was 64 years (30 to 88). The diagnosis was osteoarthritis (OA) in 151 hips (primary in 18 hips, and secondary to dysplasia in 133) and non-OA in 12 hips. A posterolateral approach with repair of the external rotators was used in 134 hips and an anterior approach in 29 hips. We measured changes in leg length and offset on radiographs, and femoral anteversion, internal rotation of the hip and lateral patellar tilt on CT scans, pre- and post-operatively. . Results. The mean internal rotation increased by 11° (-15° to 46°) and was associated with underlying disease (OA), pre-operative range of internal rotation, gender, surgical approach, leg lengthening, and change of femoral anteversion (adjusted R. 2. : 0.253, p < 0.001). The mean lateral patellar tilt increased by 4° (-5° to 14°) and was associated with age, leg lengthening, and increment of hip internal rotation (adjusted R. 2. : 0.193, p < 0.001). Conclusion. Both internal rotation of the hip at rest and lateral patellar tilt are increased after THA. Changes in rotation after THA may affect gait, daily activities, the rate of dislocation of the hip, and ipsilateral knee pain. Take home message: Internal rotation of the hip at rest and lateral patellar tilt increase after THA. Cite this article: Bone Joint J 2016;98-B:349–58

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. This paper aims to review the evidence for patient-related factors associated with less favourable outcomes following hip arthroscopy. Methods. Literature reporting on preoperative patient-related risk factors and outcomes following hip arthroscopy were systematically identified from a computer-assisted literature search of Pubmed (Medline), Embase, and Cochrane Library using Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines and a scoping review. Results. Assessment of these texts yielded 101 final articles involving 90,315 hips for qualitative analysis. The most frequently reported risk factor related to a less favourable outcome after hip arthroscopy was older age and preoperative osteoarthritis of the hip. This was followed by female sex and patients who have low preoperative clinical scores, severe hip dysplasia, altered hip morphology (excess acetabular retroversion or excess femoral anteversion or retroversion), or a large cam deformity. Patients receiving workers’ compensation or with rheumatoid arthritis were also more likely to have a less favourable outcome after hip arthroscopy. There is evidence that obesity, smoking, drinking alcohol, and a history of mental illness may be associated with marginally less favourable outcomes after hip arthroscopy. Athletes (except for ice hockey players) enjoy a more rapid recovery after hip arthroscopy than non-athletes. Finally, patients who have a favourable response to local anaesthetic are more likely to have a favourable outcome after hip arthroscopy. Conclusion. Certain patient-related risk factors are associated with less favourable outcomes following hip arthroscopy. Understanding these risk factors will allow the appropriate surgical indications for hip arthroscopy to be further refined and help patients to comprehend their individual risk profile. Cite this article: Bone Joint J 2020;102-B(7):822–831

The accurate reconstruction of hip anatomy and biomechanics is thought to be important in achieveing good clinical outcomes following total hip arthroplasty (THA). To this end some newer hip designs have introduced further modularity into the design of the femoral component such that neck­shaft angle and anteversion, which can be adjusted intra-operatively. The clinical effect of this increased modularity is unknown. We have investigated the changes in these anatomical parameters following conventional THA with a prosthesis of predetermined neck–shaft angle and assessed the effect of changes in the hip anatomy on clinical outcomes. . In total, 44 patients (mean age 65.3 years (standard deviation (. sd. ) 7); 17 male/27 female; mean body mass index 26.9 (kg/m²) (. sd. 3.1)) underwent a pre- and post-operative three-dimensional CT scanning of the hip. The pre- and post-operative neck–shaft angle, offset, hip centre of rotation, femoral anteversion, and stem alignment were measured. Additionally, a functional assessment and pain score were evaluated before surgery and at one year post-operatively and related to the post-operative anatomical changes. The mean pre-operative neck–shaft angle was significantly increased by 2.8° from 128° (. sd.  6.2; 119° to 147°) to 131° (. sd. 2.1; 127° to 136°) (p = 0.009). The mean pre-operative anteversion was 24.9° (. sd. 8; 7.9 to 39.1) and reduced to 7.4° (. sd. 7.3; -11.6° to 25.9°) post-operatively (p < 0.001). The post-operative changes had no influence on function and pain. Using a standard uncemented femoral component, high pre- and post-operative variability of femoral anteversion and neck–shaft angles was found with a significant decrease of the post-operative anteversion and slight increase of the neck–shaft angles, but without any impact on clinical outcome. Cite this article: Bone Joint J 2015;97-B:1615–22

Aims. A borderline dysplastic hip can behave as either stable or unstable and this makes surgical decision making challenging. While an unstable hip may be best treated by acetabular reorientation, stable hips can be treated arthroscopically. Several imaging parameters can help to identify the appropriate treatment, including the Femoro-Epiphyseal Acetabular Roof (FEAR) index, measured on plain radiographs. The aim of this study was to assess the reliability and the sensitivity of FEAR index on MRI compared with its radiological measurement. Patients and Methods. The technique of measuring the FEAR index on MRI was defined and its reliability validated. A retrospective study assessed three groups of 20 patients: an unstable group of ‘borderline dysplastic hips’ with lateral centre edge angle (LCEA) less than 25° treated successfully by periacetabular osteotomy; a stable group of ‘borderline dysplastic hips’ with LCEA less than 25° treated successfully by impingement surgery; and an asymptomatic control group with LCEA between 25° and 35°. The following measurements were performed on both standardized radiographs and on MRI: LCEA, acetabular index, femoral anteversion, and FEAR index. Results. The FEAR index showed excellent intraobserver and interobserver reliability on both MRI and radiographs. The FEAR index was more reliable on radiographs than on MRI. The FEAR index on MRI was lower in the stable borderline group (mean -4.2° (. sd. 9.1°)) compared with the unstable borderline group (mean 7.9° (. sd. 6.8°)). With a FEAR index cut-off value of 2°, 90% of patients were correctly identified as stable or unstable using the radiological FEAR index, compared with 82.5% using the FEAR index on MRI. The FEAR index was a better predictor of instability on plain radiographs than on MRI. Conclusion. The FEAR index measured on MRI is less reliable and less sensitive than the FEAR index measured on radiographs. The cut-off value of 2° for radiological FEAR index predicted hip stability with 90% probability. Cite this article: Bone Joint J 2019;101-B:1578–1584

Dislocation remains a major concern after total hip replacement, and is often attributed to malposition of the components. The optimum position for placement of the components remains uncertain. We have attempted to identify a relatively safe zone in which movement of the hip will occur without impingement, even if one component is positioned incorrectly. A three-dimensional computer model was designed to simulate impingement and used to examine 125 combinations of positioning of the components in order to allow maximum movement without impingement. Increase in acetabular and/or femoral anteversion allowed greater internal rotation before impingement occurred, but decreases the amount of external rotation. A decrease in abduction of the acetabular components increased internal rotation while decreasing external rotation. Although some correction for malposition was allowable on the opposite side of the joint, extreme degrees could not be corrected because of bony impingement. We introduce the concept of combined component position, in which anteversion and abduction of the acetabular component, along with femoral anteversion, are all defined as critical elements for stability

Aims. Our aim was to evaluate the radiographic characteristics of patients undergoing total hip arthroplasty (THA) for the potential of posterior bony impingement using CT simulations. Patients and Methods. Virtual CT data from 112 patients who underwent THA were analysed. There were 40 men and 72 women. Their mean age was 59.1 years (41 to 76). Associations between radiographic characteristics and posterior bony impingement and the range of external rotation of the hip were evaluated. In addition, we investigated the effects of pelvic tilt and the neck/shaft angle and femoral offset on posterior bony impingement. Results. The range of external rotation and the ischiofemoral length were significantly lower, while femoral anteversion, the ischial ratio, and ischial angle were significantly higher in patients with posterior bony impingement compared with those who had implant impingement (p <  0.05). The range of external rotation positively correlated with ischiofemoral length (r = 0.49, p < 0.05), and negatively correlated with ischial length (r = -0.49, p < 0.05), ischial ratio (r =- 0.49, p < 0.05) and ischial angle (r = -0.55, p < 0.05). The range of external rotation was lower in patients with posterior pelvic tilt (p < 0.05) and in those with a high offset femoral component (p < 0.05) due to posterior bony impingement. Conclusion. Posterior bony impingement after THA is more likely in patients with a wider ischium and a narrow ischiofemoral space. A high femoral offset and posterior pelvic tilt are also risk factors for this type of impingement. Cite this article: Bone Joint J 2017;99-B:1140–6

There is much debate about the nature and extent of deformities in the proximal femur in children with cerebral palsy. Most authorities accept that increased femoral anteversion is common, but its incidence, severity and clinical significance are less clear. Coxa valga is more controversial and many authorities state that it is a radiological artefact rather than a true deformity. We measured femoral anteversion clinically and the neck-shaft angle radiologically in 292 children with cerebral palsy. This represented 78% of a large, population-based cohort of children with cerebral palsy which included all motor types, topographical distributions and functional levels as determined by the gross motor function classification system. The mean femoral neck anteversion was 36.5° (11° to 67.5°) and the mean neck-shaft angle 147.5° (130° to 178°). These were both increased compared with values in normally developing children. The mean femoral neck anteversion was 30.4° (11° to 50°) at gross motor function classification system level I, 35.5° (8° to 65°) at level II and then plateaued at approximately 40.0° (25° to 67.5°) at levels III, IV and V. The mean neck-shaft angle increased in a step-wise manner from 135.9° (130° to 145°) at gross motor function classification system level I to 163.0° (151° to 178°) at level V. The migration percentage increased in a similar pattern and was closely related to femoral deformity. Based on these findings we believe that displacement of the hip in patients with cerebral palsy can be explained mainly by the abnormal shape of the proximal femur, as a result of delayed walking, limited walking or inability to walk. This has clinical implications for the management of hip displacement in children with cerebral palsy

Aims

Femoral component anteversion is an important factor in the success of total hip arthroplasty (THA). This retrospective study aimed to investigate the accuracy of femoral component anteversion with the Mako THA system and software using the Exeter cemented femoral component, compared to the Accolade II cementless femoral component.

The factors involved in the mechanism leading to traumatic posterior dislocation of the hip are examined. In 47 adult patients who had previously suffered such a dislocation, ultrasound scans were used to measure femoral anteversion on both the affected and the uninjured side. In 36 normal adult volunteers, used as controls, similar measurements were made. Femoral anteversion on both the injured and uninjured side was significantly reduced in the patients compared with the volunteers. These findings are discussed in the light of previous work which indicates that medial rotation is a factor in the mechanism of posterior dislocation of the hip. It is suggested that reduced anteversion acts like medial rotation to make the hip more susceptible to posterior dislocation, and that the less the anteversion the more likely is the injury to be a dislocation rather than a fracture-dislocation. It is concluded that patients who suffer such dislocated hips belong at one extreme of the normal population, having either reduced femoral anteversion or even retroversion, and that this anatomical feature selects towards hip dislocation rather than to injury of the femoral shaft, knee or tibia during the appropriate type of accident

In 1937 Blount described a series of 28 patients with ‘Tibia vara’. Since then, a number of deformities in the tibia and the femur have been described in association with this condition. We analysed 14 children with Blount’s disease who were entered into a cross-sectional study. Their mean age was 10 (2 to 18). They underwent a clinical assessment of the rotational profile of their legs and a CT assessment of the angle of anteversion of their hips (femoral version). We compared our results to previously published controls. A statistically significant increase in femoral anteversion was noted in the affected legs, with on average the femurs in patients with Blount’s disease being 26° more anteverted than those in previously published controls. We believe this to be a previously unrecognised component of Blount’s disease, and that the marked intoeing seen in the disease may be partly caused by internal femoral version, in addition to the well-recognised internal tibial version

Aims

To clarify the mid-term results of transposition osteotomy of the acetabulum (TOA), a type of spherical periacetabular osteotomy, combined with structural allograft bone grafting for severe hip dysplasia.

Aims

This study reports mid-term outcomes after periacetabular osteotomy (PAO) exclusively in a borderline hip dysplasia (BHD) population to provide a contrast to published outcomes for arthroscopic surgery of the hip in BHD.

A clinical and radiological study was conducted on 97 total hip replacements performed for congenital hip dislocation in 79 patients between 1989 and 1998 using a three-dimensional custom-made cementless stem. The mean age at operation was 48 years (17 to 72) and the mean follow-up was for 123 months (83 to 182). According to the Crowe classification, there were 37 class I, 28 class II, 13 class III and 19 class IV hips. The mean leg lengthening was 25 mm (5 to 58), the mean pre-operative femoral anteversion was 38.6° (2° to 86°) and the mean correction in the prosthetic neck was −23.6° (−71° to 13°). The mean Harris hip score improved from 58 (15 to 84) to 93 (40 to 100) points. A revision was required in six hips (6.2%). The overall survival rate was 89.5% (95% confidence interval 89.2 to 89.8) at 13 years when two hips were at risk. This custom-made cementless femoral component, which can be accommodated in the abnormal proximal femur and will correct the anteversion and frontal offset, provided good results without recourse to proximal femoral corrective osteotomy

The anterior cruciate ligament (ACL) is frequently injured in elite athletes, with females up to eight times more likely to suffer an ACL tear than males. Biomechanical and hormonal factors have been thoroughly investigated; however, there remain unknown factors that need investigation. The mechanism of injury differs between males and females, and anatomical differences contribute significantly to the increased risk in females. Hormonal factors, both endogenous and exogenous, play a role in ACL laxity and may modify the risk of injury. However, data are still limited, and research involving oral contraceptives is potentially associated with methodological and ethical problems. Such characteristics can also influence the outcome after ACL reconstruction, with higher failure rates in females linked to a smaller diameter of the graft, especially in athletes aged < 21 years. The addition of a lateral extra-articular tenodesis can improve the outcomes after ACL reconstruction and reduce the risk of failure, and it should be routinely considered in young elite athletes. Sex-specific environmental differences can also contribute to the increased risk of injury, with more limited access to and availablility of advanced training facilities for female athletes. In addition, football kits are designed for male players, and increased attention should be focused on improving the quality of pitches, as female leagues usually play the day after male leagues. The kit, including boots, the length of studs, and the footballs themselves, should be tailored to the needs and body shapes of female athletes. Specific physiotherapy programmes and training protocols have yielded remarkable results in reducing the risk of injury, and these should be extended to school-age athletes. Finally, psychological factors should not be overlooked, with females’ greater fear of re-injury and lack of confidence in their knee compromising their return to sport after ACL injury. Both intrinsic and extrinsic factors should be recognized and addressed to optimize the training programmes which are designed to prevent injury, and improve our understanding of these injuries.

Cite this article: Bone Joint J 2023;105-B(10):1033–1037.

Aims

Spinopelvic pathology increases the risk for instability following total hip arthroplasty (THA), yet few studies have evaluated how pathology varies with age or sex. The aims of this study were: 1) to report differences in spinopelvic parameters with advancing age and between the sexes; and 2) to determine variation in the prevalence of THA instability risk factors with advancing age.

Rotational deformity following intramedullary nailing may cause symptoms and require surgical correction by osteotomy. Reamed, locked intramedullary nailing may be performed, but concern about cortical blood supply and potential pulmonary dysfunction from reaming have led many surgeons to limit this and use smaller diameter nails. Slotted nails are commonly used but are less stiff in torsion than the newer unslotted nails, particularly at the lower diameters. We report two cased of recurrent femoral rotational deformity after using statically interlocked slotted intramedullary nails to correct existing femoral rotational deformities. These patients show that small diameter statically interlocked femoral nails with diminished bone-nail contact must be stiff enough in rotation to avoid potential recurrence

Hip resurfacing is being performed more frequently in the United Kingdom. The possible benefits include more accurate restoration of leg length, femoral offset and femoral anteversion than occurs after total hip arthroplasty (THA). We compared anteroposterior radiographs from 26 patients who had undergone hybrid THA (uncemented cup/cemented stem), with 28 who had undergone Birmingham Hip Resurfacing arthroplasty (BHR). We measured the femoral offset, femoral length, acetabular offset and acetabular height with reference to the normal contralateral hip. The data were analysed by paired t-tests. There was a significant reduction in femoral offset (p = 0.0004) and increase in length (p = 0.001) in the BHR group. In the THA group, there was a significant reduction in acetabular offset (p = 0.0003), but femoral offset and overall hip length were restored accurately. We conclude that hip resurfacing does not restore hip mechanics as accurately as THA

Aims. In Asia and the Middle-East, people often flex their knees deeply in order to perform activities of daily living. The purpose of this study was to investigate the 3D kinematics of normal knees during high-flexion activities. Our hypothesis was that the femorotibial rotation, varus-valgus angle, translations, and kinematic pathway of normal knees during high-flexion activities, varied according to activity. Materials and Methods. We investigated the in vivo kinematics of eight normal knees in four male volunteers (mean age 41.8 years; 37 to 53) using 2D and 3D registration technique, and modelled the knees with a computer aided design program. Each subject squatted, kneeled, and sat cross-legged. We evaluated the femoral rotation and varus-valgus angle relative to the tibia and anteroposterior translation of the medial and lateral side, using the transepicodylar axis as our femoral reference relative to the perpendicular projection on to the tibial plateau. This method evaluates the femur medially from what has elsewhere been described as the extension facet centre, and differs from the method classically applied. . Results. During squatting and kneeling, the knees displayed femoral external rotation. When sitting cross-legged, femurs displayed internal rotation from 10° to 100°. From 100°, femoral external rotation was observed. No significant difference in varus-valgus angle was seen between squatting and kneeling, whereas a varus position was observed from 140° when sitting cross-legged. The measure kinematic pathway using our methodology found during squatting a medial pivoting pattern from 0° to 40° and bicondylar rollback from 40° to 150°. During kneeling, a medial pivot pattern was evident. When sitting cross-legged, a lateral pivot pattern was seen from 0° to 100°, and a medial pivot pattern beyond 100°. Conclusion. The kinematics of normal knees during high flexion are variable according to activity. Nevertheless, our study was limited to a small number of male patients using a different technique to report the kinematics than previous publications. Accordingly, caution should be observed in generalizing our findings. Cite this article: Bone Joint J 2018;100-B:50–5

The appearance of the ‘grand-piano sign’ on the anterior resected surface of the femur has been considered to be a marker for correct femoral rotational alignment during total knee replacement. Our study was undertaken to assess quantitatively the morphological patterns on the resected surface after anterior femoral resection with various angles of external rotation, using a computer-simulation technique. A total of 50 right distal femora with varus osteoarthritis in 50 Korean patients were scanned using computerised tomography. Computer image software was used to simulate the anterior femoral cut, which was applied at an external rotation of 0°, 3° and 6° relative to the posterior condylar axis, and parallel to the surgical and clinical epicondylar axes in each case. The morphological patterns on the resected surface were quantified and classified as the ‘grand-piano sign’, ‘the boot sign’ and the ‘butterfly sign’. The surgeon can use the analogy of these quantified sign patterns to ensure that a correct rotational alignment has been obtained intra-operatively

Malpositioning of the trochanteric entry point during the introduction of an intramedullary nail may cause iatrogenic fracture or malreduction. Although the optimal point of insertion in the coronal plane has been well described, positioning in the sagittal plane is poorly defined. . The paired femora from 374 cadavers were placed both in the anatomical position and in internal rotation to neutralise femoral anteversion. A marker was placed at the apparent apex of the greater trochanter, and the lateral and anterior offsets from the axis of the femoral shaft were measured on anteroposterior and lateral photographs. Greater trochanteric morphology and trochanteric overhang were graded. The mean anterior offset of the apex of the trochanter relative to the axis of the femoral shaft was 5.1 mm (. sd. 4.0) and 4.6 mm (. sd. 4.2) for the anatomical and neutralised positions, respectively. The mean lateral offset of the apex was 7.1 mm (. sd. 4.6) and 6.4 mm (. sd. 4.6), respectively. Placement of the entry position at the apex of the greater trochanter in the anteroposterior view does not reliably centre an intramedullary nail in the sagittal plane. Based on our findings, the site of insertion should be about 5 mm posterior to the apex of the trochanter to allow for its anterior offset. Cite this article: Bone Joint J 2014;96-B:1274–81

Aims

Spinopelvic mobility plays an important role in functional acetabular component position following total hip arthroplasty (THA). The primary aim of this study was to determine if spinopelvic hypermobility persists or resolves following THA. Our second aim was to identify patient demographic or radiological factors associated with hypermobility and resolution of hypermobility after THA.

We describe a technique of femoral derotation osteotomy performed according to the Ilizarov principles of percutaneous corticotomy and fixation with a frame. We performed 24 femoral osteotomies in 16 patients, four with cerebral palsy and 12 with idiopathic femoral anteversion. All had rapid union and there were few complications. The advantages of the method include early ambulation, good control of rotation and axial alignment, and minimal scarring

Computerised tomography is useful in the diagnosis of abnormalities of the hip in children, particularly in assessing the size and shape of the acetabulum, the position and congruity of the femoral head relative to the acetabulum, and the degree of femoral anteversion or retroversion. It is most useful when limited hip movement and previous operations preclude adequate clinical examination and assessment by routine radiographic techniques. It is not recommended for routine use in screening congenital dislocation of the hip or in diagnosis or follow-up of Perthes' disease or slipped capital femoral epiphysis

Aims

A comprehensive classification for coronal lower limb alignment with predictive capabilities for knee balance would be beneficial in total knee arthroplasty (TKA). This paper describes the Coronal Plane Alignment of the Knee (CPAK) classification and examines its utility in preoperative soft tissue balance prediction, comparing kinematic alignment (KA) to mechanical alignment (MA).

A three-dimensional computer model of a total hip replacement was used to examine the relationship between the position of the components, the range of motion and the prosthetic joint contact area. Horizontal acetabular positions with small amounts of acetabular and femoral anteversion provide the largest contact areas, but result in limited joint movement. These data will allow surgeons to select implant positions that will provide the largest possible joint contact area for a given joint range of motion although these are conflicting goals. In some component positions a truncated spherical prosthetic head resulted in smaller contact areas than a completely spherical head

Aims

Modern total knee arthroplasty (TKA) prostheses are designed to restore near normal kinematics including high flexion. Kneeling is a high flexion, kinematically demanding activity after TKA. The debate about design choice has not yet been informed by six-degrees-of-freedom in vivo kinematics. This prospective randomized clinical trial compared kneeling kinematics in three TKA designs.

Aims

Robotic-assisted total knee arthroplasty (RA-TKA) is theoretically more accurate for component positioning than TKA performed with mechanical instruments (M-TKA). Furthermore, the ability to incorporate soft-tissue laxity data into the plan prior to bone resection should reduce variability between the planned polyethylene thickness and the final implanted polyethylene. The purpose of this study was to compare accuracy to plan for component positioning and precision, as demonstrated by deviation from plan for polyethylene insert thickness in measured-resection RA-TKA versus M-TKA.

A technique for performing allograft-augmented revision total knee replacement (TKR) using computer assistance is described, on the basis of the results in 14 patients. Bone deficits were made up with impaction grafting. Femoral grafting was made possible by the construction of a retaining wall or dam which allowed pressurisation and retention of the graft. Tibial grafting used a mixture of corticocancellous and morsellised allograft. The position of the implants was monitored by the computer system and adjusted while the cement was setting. The outcome was determined using a six-parameter, quantitative technique (the Perth CT protocol) which measured the alignment of the prosthesis and provided an objective score. The final outcomes were not perfect with errors being made in femoral rotation and in producing a mismatch between the femoral and tibial components. In spite of the shortcomings the alignments were comparable in accuracy with those after primary TKR. Computer assistance shows considerable promise in producing accurate alignment in revision TKR with bone deficits

The results obtained in a consecutive series of thirty-seven Pemberton operations for congenital dislocation or subluxation of the hip are reported. Over the period under review, 1967 to 1973, it was the only type of acetabuloplasty employed at Winford. Unless the mandatory concentric reduction could be obtained with ease, preliminary open reduction was favoured, especially in cases of primary care. Femoral rotation osteotomy was added for marked anteversion. The programme was designed to be complete inside fourteen weeks, and was so for eighteen hips. Secondary acetabuloplasty was performed on hips with instability or dislocation persisting despite previous treatment. The operations were performed from eighteen months to thirteen years of age. One initial failure required a repeat operation which was successful, but one severely dysplastic hip remained so. The average follow-up was six years

Aims

Alternative alignment concepts, including kinematic and restricted kinematic, have been introduced to help improve clinical outcomes following total knee arthroplasty (TKA). The purpose of this study was to evaluate the clinical results, along with patient satisfaction, following TKA using the concept of restricted kinematic alignment.

Femoroacetabular cam impingement is thought to be a cause of premature osteoarthritis of the hip. The presence of cam malformation was determined in 2803 standardised anteroposterior (AP) pelvic radiographs from the Copenhagen Osteoarthritis Study by measuring the alpha (α) angle and the triangular index, a new measure of asphericity of the femoral head. In addition, the α-angle and the triangular index were assessed on the AP and lateral hip radiographs of 82 men and 82 women randomly selected from patients scheduled for total hip replacement (THR). The influence of varying femoral rotation on the α angle and the triangular index was also determined in femoral specimens under experimental conditions. From the 2803 radiographs the mean AP α-angle was 55° (30° to 100°) in men and 45° (34° to 108°) in women. Approximately 6% of men and 2% of women had cam malformation. The α-angle and triangular index were highly inter-related. Of those patients scheduled for THR, 36 men (44%) and 28 women (35%) had cam malformation identifiable on the AP radiographs. The triangular index proved to be more reliable in detecting cam malformation when the hip was held in varying degrees of rotation. The combination of the α-angle and the triangular index will allow examination of historical radiographs for epidemiological purposes in following the natural history of the cam deformity

We have compared a new technique of computer-assisted knee arthroplasty with the current conventional jig-based technique in 70 patients randomly allocated to receive either of the methods. Post-operative CT was performed according to the Perth CT Knee Arthroplasty protocol and pre- and post-operative Maquet views of the limb were taken. Intra-operative and peri-operative morbidity data were collected and blood loss measured. Post-operative CT showed a significant improvement in the alignment of the components using computer-assisted surgery in regard to femoral varus/valgus (p = 0.032), femoral rotation (p = 0.001), tibial varus/valgus (p = 0.047) tibial posterior slope (p = 0.0001), tibial rotation (p = 0.011) and femorotibial mismatch (p = 0.037). Standing alignment was also improved (p = 0.004) and blood loss was less (p = 0.0001). Computer-assisted surgery took longer with a mean increase of 13 minutes (p = 0.0001)

Aims

The prevalence of combined abnormalities of femoral torsion (FT) and tibial torsion (TT) is unknown in patients with femoroacetabular impingement (FAI) and hip dysplasia. This study aimed to determine the prevalence of combined abnormalities of FT and TT, and which subgroups are associated with combined abnormalities of FT and TT.

We have observed damage to the labrum as a result of repetitive acetabular impingement in non-dysplastic hips, in which the femoral neck appears to abut against the acetabular labrum and a non-spherical femoral head to press against the labrum and adjacent cartilage. In both mechanisms anatomical variations of the proximal femur may be a factor. We have measured the orientation of the femoral neck and the offset of the head at various circumferential positions, using MRI data from volunteers with no osteoarthritic changes on standard radiographs. Compared with the control subjects, paired for gender and age, patients showed a significant reduction in mean femoral anteversion and mean head-neck offset on the anterior aspect of the neck. This was consistent with the site of symptomatic impingement in flexion and internal rotation, and with lesions of the adjacent rim. Furthermore, when stratified for gender and age, and compared with the control group, the mean femoral head-neck offset was significantly reduced in the lateral-to-anterior aspect of the neck for young men, and in the anterolateral-to-anterior aspect of the neck for older women. For patients suspected of having impingement of the rim, anatomical variations in the proximal femur should be considered as a possible cause