Aims. Mechanical impingement of the iliopsoas (IP) tendon accounts for 2% to 6% of persistent postoperative pain after total hip arthroplasty (THA). The most common initiator is anterior acetabular component protrusion, where the anterior margin is not covered by anterior acetabular wall. A CT scan can be used to identify and measure this overhang; however, no threshold exists for determining symptomatic anterior IP impingement due to overhang. A case-control study was conducted in which CT scan measurements were used to define a threshold that differentiates patients with IP impingement from asymptomatic patients after THA. Methods. We analyzed the CT scans of 622 patients (758 THAs) between May 2011 and May 2020. From this population, we identified 136 patients with symptoms suggestive of IP impingement. Among them, six were subsequently excluded: three because the diagnosis was refuted intraoperatively, and three because they had another obvious cause of impingement, leaving 130 hips (130 patients) in the study (impingement) group. They were matched to a control group of 138 asymptomatic hips (138 patients) after THA. The anterior acetabular component overhang was measured on an axial CT slice based on anatomical landmarks (orthogonal to the pelvic axis). Results. The impingement group had a median overhang of 8 mm (interquartile range (IQR) 5 to 11) versus 0 mm (IQR 0 to 4) for the control group (p < 0.001). Using receiver operating characteristic curves, an overhang threshold of 4 mm was best correlated with a diagnosis of impingement (sensitivity 79%, specificity 85%; positive predictive value 75%, negative predictive value 85%). Conclusion. Pain after THA related to IP impingement can be reasonably linked to acetabular overhang if it exceeds 4 mm on a CT scan. Below this threshold, it seems logical to look for another cause of IP irritation or another reason for the pain after THA before concluding that impingement is present. Cite this article: Bone Joint J 2024;106-B(3 Supple A):97–103

Aims. Femoroacetabular impingement (FAI) patients report exacerbation of hip pain in deep flexion. However, the exact impingement location in deep flexion is unknown. The aim was to investigate impingement-free maximal flexion, impingement location, and if cam deformity causes hip impingement in flexion in FAI patients. Methods. A retrospective study involving 24 patients (37 hips) with FAI and femoral retroversion (femoral version (FV) < 5° per Murphy method) was performed. All patients were symptomatic (mean age 28 years (SD 9)) and had anterior hip/groin pain and a positive anterior impingement test. Cam- and pincer-type subgroups were analyzed. Patients were compared to an asymptomatic control group (26 hips). All patients underwent pelvic CT scans to generate personalized CT-based 3D models and validated software for patient-specific impingement simulation (equidistant method). Results. Mean impingement-free flexion of patients with mixed-type FAI (110° (SD 8°)) and patients with pincer-type FAI (112° (SD 8°)) was significantly (p < 0.001) lower compared to the control group (125° (SD 13°)). The frequency of extra-articular subspine impingement was significantly (p < 0.001) increased in patients with pincer-type FAI (57%) compared to cam-type FAI (22%) in 125° flexion. Bony impingement in maximal flexion was located anterior-inferior at femoral four and five o’clock position in patients with cam-type FAI (63% (10 of 16 hips) and 37% (6 of 10 hips)), and did not involve the cam deformity. The cam deformity did not cause impingement in maximal flexion. Conclusion. Femoral impingement in maximal flexion was located anterior-inferior distal to the cam deformity. This differs to previous studies, a finding which could be important for FAI patients in order to avoid exacerbation of hip pain in deep flexion (e.g. during squats) and for hip arthroscopy (hip-preservation surgery) for planning of bone resection. Hip impingement in flexion has implications for daily activities (e.g. putting on shoes), sports, and sex. Cite this article: Bone Joint Res 2023;12(1):22–32

Aims. Precise implant positioning, tailored to individual spinopelvic biomechanics and phenotype, is paramount for stability in total hip arthroplasty (THA). Despite a few studies on instability prediction, there is a notable gap in research utilizing artificial intelligence (AI). The objective of our pilot study was to evaluate the feasibility of developing an AI algorithm tailored to individual spinopelvic mechanics and patient phenotype for predicting impingement. Methods. This international, multicentre prospective cohort study across two centres encompassed 157 adults undergoing primary robotic arm-assisted THA. Impingement during specific flexion and extension stances was identified using the virtual range of motion (ROM) tool of the robotic software. The primary AI model, the Light Gradient-Boosting Machine (LGBM), used tabular data to predict impingement presence, direction (flexion or extension), and type. A secondary model integrating tabular data with plain anteroposterior pelvis radiographs was evaluated to assess for any potential enhancement in prediction accuracy. Results. We identified nine predictors from an analysis of baseline spinopelvic characteristics and surgical planning parameters. Using fivefold cross-validation, the LGBM achieved 70.2% impingement prediction accuracy. With impingement data, the LGBM estimated direction with 85% accuracy, while the support vector machine (SVM) determined impingement type with 72.9% accuracy. After integrating imaging data with a multilayer perceptron (tabular) and a convolutional neural network (radiograph), the LGBM’s prediction was 68.1%. Both combined and LGBM-only had similar impingement direction prediction rates (around 84.5%). Conclusion. This study is a pioneering effort in leveraging AI for impingement prediction in THA, utilizing a comprehensive, real-world clinical dataset. Our machine-learning algorithm demonstrated promising accuracy in predicting impingement, its type, and direction. While the addition of imaging data to our deep-learning algorithm did not boost accuracy, the potential for refined annotations, such as landmark markings, offers avenues for future enhancement. Prior to clinical integration, external validation and larger-scale testing of this algorithm are essential. Cite this article: Bone Jt Open 2024;5(8):671–680

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

Aims. The aim of this study was to examine the real time in vivo kinematics of the hip in patients with cam-type femoroacetabular impingement (FAI). Patients and Methods. A total of 50 patients (83 hips) underwent 4D dynamic CT scanning of the hip, producing real time osseous models of the pelvis and femur being moved through flexion, adduction, and internal rotation. The location and size of the cam deformity and its relationship to the angle of flexion of the hip and pelvic tilt, and the position of impingement were recorded. Results. In these patients with cam-type FAI, there was significant correlation between the alpha angle and flexion to the point of impingement (mean 41.36°; 14.32° to 57.95°) (R = -0.5815 and p = < 0.001). Patients with a large cam deformity (alpha angle > 78°) had significantly less flexion to the point of impingement (mean 36.30°; 14.32° to 55.18°) than patients with a small cam deformity (alpha angle 60° to 78°) (mean 45.34°; 27.25° to 57.95°) (p = < 0.001). Conclusion. This study has shown that cam-type impingement can occur early in flexion (40°), particularly in patients with large anterior deformities. These patients risk chondrolabral damage during routine activities such as walking, and going up stairs. These findings offer important insights into the cause of the symptoms, the mechanisms of screening and the forms of treatment available for these patients. Cite this article: Bone Joint J 2017;99-B(4 Supple B):41–8

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. Pelvic tilt (PT) can significantly change the functional orientation of the acetabular component and may differ markedly between patients undergoing total hip arthroplasty (THA). Patients with stiff spines who have little change in PT are considered at high risk for instability following THA. Femoral component position also contributes to the limits of impingement-free range of motion (ROM), but has been less studied. Little is known about the impact of combined anteversion on risk of impingement with changing pelvic position. Methods. We used a virtual hip ROM (vROM) tool to investigate whether there is an ideal functional combined anteversion for reduced risk of hip impingement. We collected PT information from functional lateral radiographs (standing and sitting) and a supine CT scan, which was then input into the vROM tool. We developed a novel vROM scoring system, considering both seated flexion and standing extension manoeuvres, to quantify whether hips had limited ROM and then correlated the vROM score to component position. Results. The vast majority of THA planned with standing combined anteversion between 30° to 50° and sitting combined anteversion between 45° to 65° had a vROM score > 99%, while the majority of vROM scores less than 99% were outside of this zone. The range of PT in supine, standing, and sitting positions varied widely between patients. Patients who had little change in PT from standing to sitting positions had decreased hip vROM. Conclusion. It has been shown previously that an individual’s unique spinopelvic alignment influences functional cup anteversion. But functional combined anteversion, which also considers stem position, should be used to identify an ideal THA position for impingement-free ROM. We found a functional combined anteversion zone for THA that may be used moving forward to place total hip components. Cite this article: Bone Jt Open 2021;2(10):834–841

We report the ulnar impingement syndrome, which is caused by a shortened ulna impinging on the distal radius and causing a painful, disabling pseudarthrosis. Of the 11 cases reported, 10 were due to excision of the distal ulna after injury to the wrist; the other was a result of a growth arrest after a fracture of the distal ulna in a child. The symptoms are a painful, clicking wrist and a weak grip; clinical examination reveals a narrow wrist with pain on compression of the radius and ulna and on forced supination. Radiographs in the majority of cases show scalloping of the distal radius corresponding to the site of impingement. The mechanism by which ulnar impingement occurs after radio-ulnar convergence is illustrated. The plan of management for the young patient with traumatic dysfunction of the distal radio-ulnar joint is discussed; excision of the lower end of the ulna is not advised in such patients

Femoroacetabular impingement is a well-documented cause of hip pain. There is, however, increasing evidence for the presence of a previously unrecognised impingement-type condition around the hip – ischiofemoral impingement. This is caused by abnormal contact between the lesser trochanter of the femur and the ischium, and presents as atypical groin and/or posterior buttock pain. The symptoms are gradual in onset and may be similar to those of iliopsoas tendonitis, hamstring injury or bursitis. The presence of ischiofemoral impingement may be indicated by pain caused by a combination of hip extension, adduction and external rotation. Magnetic resonance imaging demonstrates inflammation and oedema in the ischiofemoral space and quadratus femoris, and is distinct from an acute tear. To date this has only appeared in the specialist orthopaedic literature as a problem that has developed after total hip replacement, not in the unreplaced joint

Dislocation is one of the most common causes of patient and surgeon dissatisfaction following hip replacement and to treat it, the causes must first be understood. Patient factors include age greater than 70 years, medical comorbidities, female gender, ligamentous laxity, revision surgery, issues with the abductors, and patient education. Surgeon factors include the annual quantity of procedures and experience, the surgical approach, adequate restoration of femoral offset and leg length, component position, and soft-tissue or bony impingement. Implant factors include the design of the head and neck region, and so-called skirts on longer neck lengths. There should be offset choices available in order to restore soft-tissue tension. Lipped liners aid in gaining stability, yet if improperly placed may result in impingement and dislocation. Late dislocation may result from polyethylene wear, soft-tissue destruction, trochanteric or abductor disruption and weakness, or infection. Understanding the causes of hip dislocation facilitates prevention in a majority of instances. Proper pre-operative planning includes the identification of patients with a high offset in whom inadequate restoration of offset will reduce soft-tissue tension and abductor efficiency. Component position must be accurate to achieve stability without impingement. Finally, patient education cannot be over-emphasised, as most dislocations occur early, and are preventable with proper instructions. Cite this article: Bone Joint J 2013;95-B, Supple A:67–9

Thirty-three patients with impingement syndrome of the rotator cuff were studied before and at operation. It was shown that the rotator cuff lengthens and twists during elevation of the arm. Elevation is achieved by early glenohumeral abduction and continuous flexion and external rotation. The range of free rotation at the glenohumeral joint diminishes progressively during elevation. Rotator cuff impingement occurs towards the end of the early glenohumeral abduction. Excision arthroplasty of the acromioclavicular joint and anterior acromioplasty is highly effective for impingement under the acromion, but only moderately effective where impingement is under the acromioclavicular joint

Inversion injuries of the ankle are common and most are managed adequately by functional treatment. A significant number will, however, remain symptomatic. Synovial impingement is one cause of continuing pain. This condition is often difficult to diagnose because the physical signs and investigations are non-specific. If the diagnosis is made, treatment by arthroscopic debridement has been shown to be highly effective. Our aim was to describe a new physical sign to help in the diagnosis of anterolateral synovial impingement in the ankle. A cadaver dissection demonstrated the anatomical basis for the physical sign and a prospective clinical study involving 73 patients showed that the lateral synovial impingement test had a sensitivity of 94.8% and a specificity of 88%. We describe the test and conclude that this physical sign will be of use to practitioners treating patients with chronic pain in the ankle after injury

We performed a prospective study to assess the long-term outcome of 57 arthroscopic debridement procedures carried out to treat anterior impingement in the ankle. Using preoperative radiographs, we grouped patients according to the extent of their osteoarthritis (OA). The symptoms of those with grade-0 changes could be attributed to anterior soft-tissue impingement alone. Patients with grade-I disease had both anterior soft-tissue and osteophytic impingement, but no narrowing of the joint space. In those with grade-II OA, narrowing of the joint space was accompanied by osteophytic impingement. Radiographs taken before and after operation and at follow-up were compared to assess the recurrence of osteophytes and the progression of narrowing of the joint space. At a mean follow-up of 6.5 years (5 to 8) all patients without OA had excellent or good results. There were excellent or good results in 77% of patients with grade-I OA, despite partial or complete recurrence of osteophytes in two-thirds. In most patients with grade-II OA, narrowing of the joint space had not progressed at follow-up. There was a notable improvement in pain in these patients, 53% of whom had excellent or good results. Although some osteophytes recurred, at long-term follow-up arthroscopic excision of soft-tissue overgrowths and osteophytes proved to be an effective way of treating anterior impingement of the ankle in patients who had no narrowing of the joint space

A total of 92 patients with symptoms for over six months due to subacromial impingement of the shoulder, who were being treated with physiotherapy, were included in this study. While continuing with physiotherapy they waited a further six months for surgery. They were divided into three groups based on the following four clinical and radiological criteria: temporary benefit following steroid injection, pain in the mid-arc of abduction, a consistently positive Hawkins test and radiological evidence of impingement. Group A fulfilled all four criteria, group B three criteria and group C two criteria. A total of nine patients improved while waiting for surgery and were excluded, leaving 83 who underwent arthroscopic subacromial decompression (SAD). The new Oxford shoulder score was recorded pre-operatively and at three and 12 months post-operatively. A total of 51 patients (group A) had a significant improvement in the mean shoulder score from 18 (13 to 22) pre-operatively to 38 (35 to 42) at three months (p < 0.001). The mean score in this group was significantly better than in group B (21 patients) and C (11 patients) at this time. At one year patients in all groups showed improvement in scores, but patients in group A had a higher mean score (p = 0.01). At one year patients in groups A and B did better than those in group C (p = 0.01). Arthroscopic SAD is a beneficial intervention in selected patients. The four criteria could help identify patients in whom it is likely to be most effective

Mechanical failure because of wear or fracture of the polyethylene tibial post in posteriorly-stabilised total knee replacements has been extensively described. In this study of 12 patients with a clinically and radiologically successful NexGen LPS posteriorly-stabilised prosthesis impingement of the anterior tibial post was evaluated in vivo in three dimensions during gait using radiologically-based image-matching techniques. Impingement was observed in all images of the patients during the stance phase, although the NexGen LPS was designed to accommodate 14° of hyperextension of the component before impingement occurred. Impingement arises as a result of posterior translation of the femur during the stance phase. Further attention must therefore be given to the configuration of the anterior portion of the femoral component and the polyethylene post when designing posteriorly-stabilised total knee replacements

We have reviewed a group of patients with iliopsoas impingement after total hip replacement with radiological evidence of a well-fixed malpositioned or oversized acetabular component. A consecutive series of 29 patients (30 hips) was assessed. All had undergone a trial of conservative management with no improvement in their symptoms. Eight patients (eight hips) preferred continued conservative management (group 1), and 22 hips had either an iliopsoas tenotomy (group 2) or revision of the acetabular component and debridement of the tendon (group 3), based on clinical and radiological findings. Patients were followed clinically for at least two years, and 19 of the 22 patients (86.4%) who had surgery were contacted by phone at a mean of 7.8 years (5 to 9) post-operatively. Conservative management failed in all eight hips. At the final follow-up, operative treatment resulted in relief of pain in 18 of 22 hips (81.8%), with one hip in group 2 and three in group 3 with continuing symptoms. The Harris Hip Score was significantly better in the combined groups 2 and 3 than in group 1. There was a significant rate of complications in group 3. This group initially had better functional scores, but at final follow-up these were no different from those in group 2. Tenotomy of the iliopsoas and revision of the acetabular component are both successful surgical options. Iliopsoas tenotomy provided the same functional results as revision of the acetabular component and avoided the risks of the latter procedure

Aims. Scapular notching is a frequently observed radiographic phenomenon in reverse shoulder arthroplasty (RSA), signifying impingement of components. The purposes of this study were to evaluate the effect of glenoid component size and glenosphere type on impingement-free range of movement (ROM) for extension and internal and external rotation in a virtual RSA model, and to determine the optimal configuration to reduce the incidence of friction-type scapular notching. Materials and Methods. Preoperative CT scans obtained in 21 patients (three male, 18 female) with primary osteoarthritis were analyzed using modelling software. Two concurrent factors were tested for impingement-free ROM and translation of the centre of rotation: glenosphere diameter (36 mm vs 39 mm) and type (centred, 2 mm inferior eccentric offset, 10° inferior tilt). Results. Glenosphere size was most predictive of increased extension and external rotation, whereas lateralization of the centre of rotation was the most predictive factor for internal rotation. A larger diameter of glenosphere combined with a 10° tilted configuration demonstrated superior values for extension and external rotation, whereas the eccentric component improved internal rotation by a mean 8.9° (standard deviation 2.7°) compared with a standard concentric glenosphere. Conclusion. Glenosphere configuration can be modified to increase range of movement in RSA. Friction-type scapular notching was most effectively reduced by use of a large-diameter glenosphere with 10° inferior tilt. Cite this article: Bone Joint J 2018;100-B:1182–6

Impingement syndrome in the shoulder has generally been considered to be a clinical condition of mechanical origin. However, anomalies exist between the pathology in the subacromial space and the degree of pain experienced. These may be explained by variations in the processing of nociceptive inputs between different patients. We investigated the evidence for augmented pain transmission (central sensitisation) in patients with impingement, and the relationship between pre-operative central sensitisation and the outcomes following arthroscopic subacromial decompression. We recruited 17 patients with unilateral impingement of the shoulder and 17 age- and gender-matched controls, all of whom underwent quantitative sensory testing to detect thresholds for mechanical stimuli, distinctions between sharp and blunt punctate stimuli, and heat pain. Additionally Oxford shoulder scores to assess pain and function, and PainDETECT questionnaires to identify ‘neuropathic’ and referred symptoms were completed. Patients completed these questionnaires pre-operatively and three months post-operatively. A significant proportion of patients awaiting subacromial decompression had referred pain radiating down the arm and had significant hyperalgesia to punctate stimulus of the skin compared with controls (unpaired t-test, p < 0.0001). These are felt to represent peripheral manifestations of augmented central pain processing (central sensitisation). The presence of either hyperalgesia or referred pain pre-operatively resulted in a significantly worse outcome from decompression three months after surgery (unpaired t-test, p = 0.04 and p = 0.005, respectively). These observations confirm the presence of central sensitisation in a proportion of patients with shoulder pain associated with impingement. Also, if patients had relatively high levels of central sensitisation pre-operatively, as indicated by higher levels of punctate hyperalgesia and/or referred pain, the outcome three months after subacromial decompression was significantly worse

We report a randomised controlled trial to examine the effectiveness and cost-effectiveness of arthroscopic acromioplasty in the treatment of stage II shoulder impingement syndrome. A total of 140 patients were randomly divided into two treatment groups: supervised exercise programme (n = 70, exercise group) and arthroscopic acromioplasty followed by a similar exercise programme (n = 70, combined treatment group). The main outcome measure was self-reported pain on a visual analogue scale of 0 to 10 at 24 months, measured on the 134 patients (66 in the exercise group and 68 in the combined treatment group) for whom endpoint data were available. An intention-to-treat analysis disclosed an improvement in both groups but without statistically significant difference in outcome between the groups (p = 0.65). The combined treatment was considerably more costly. Arthroscopic acromioplasty provides no clinically important effects over a structured and supervised exercise programme alone in terms of subjective outcome or cost-effectiveness when measured at 24 months. Structured exercise treatment should be the basis for treatment of shoulder impingement syndrome, with operative treatment offered judiciously until its true merit is proven

Impingement by prominence at the femoral head-neck junction on the anterior acetabular rim may cause early osteoarthritis. Our aim was to develop a simple method to describe concavity at this junction, and then to test it by its ability to distinguish quantitatively a group of patients with clinical evidence of impingement from asymptomatic individuals who had normal hips on examination. MR scans of 39 patients with groin pain, decreased internal rotation and a positive impingement test were compared with those of 35 asymptomatic control subjects. The waist of the femoral head-neck junction was identified on tilted axial MR scans passing through the centre of the head. The anterior margin of the waist of the femoral neck was defined and measured by an angle (α). In addition, the width of the femoral head-neck junction was measured at two sites. Repeated measurements showed good reproducibility among four observers. The angle α averaged 74.0° for the patients and 42.0° for the control group (p < 0.001). Significant differences were also found between the patient and control groups for the scaled width of the femoral neck at both sites. Using standardised MRI, the symptomatic hips of patients who have impingement have significantly less concavity at the femoral head-neck junction than do normal hips. This test may be of value in patients with loss of internal rotation for which a cause is not found

Objectives. To report the five-year results of a randomised controlled trial examining the effectiveness of arthroscopic acromioplasty in the treatment of stage II shoulder impingement syndrome. Methods. A total of 140 patients were randomly divided into two groups: 1) supervised exercise programme (n = 70, exercise group); and 2) arthroscopic acromioplasty followed by a similar exercise programme (n = 70, combined treatment group). Results. The main outcome measure was self-reported pain as measured on a visual analogue scale. At the five-year assessment a total of 109 patients were examined (52 in the exercise group and 57 in the combined treatment group). There was a significant decrease in mean self-reported pain on the VAS between baseline and the five-year follow-up in both the exercise group (from 6.5 (1 to 10) to 2.2 (0 to 8); p < 0.001) and the combined treatment group (from 6.4 (2 to 10) to 1.9 (0 to 8); p < 0.001). The same trend was seen in the secondary outcome measures (disability, working ability, pain at night, Shoulder Disability Questionnaire and reported painful days). An intention-to-treat analysis showed statistically significant improvements in both groups at five years compared with baseline. Further, improvement continued between the two- and five-year timepoints. No statistically significant differences were found in the patient-centred primary and secondary parameters between the two treatment groups. Conclusions. Differences in the patient-centred primary and secondary parameters between the two treatment groups were not statistically significant, suggesting that acromioplasty is not cost-effective. Structured exercise treatment seems to be the treatment of choice for shoulder impingement syndrome

Coracoid impingement results from encroachment on the coracohumeral space, presenting as anterior shoulder pain and clicking, particularly in forward flexion, medial rotation, and adduction. In eight shoulders in seven patients, coracohumeral decompression by excision of the lateral 1.5 cm of the coracoid with re-attachment of the conjoined tendon gave pain relief in all, and complete relief in six. This procedure is described and recommended

A syndrome of back and loin pain produced by impingement of the lowest rib against the iliac crest is described in six patients. All had noticed a significant loss of height and five had osteoporosis of the vertebral column. It is suggested that mechanical irritation of the lowest rib against the iliac crest was the cause of the pain and that subperiosteal resection of the outer two-thirds of the rib would stop this irritation and relieve the symptoms. The six patients who underwent resection of the twelfth rib all obtained relief of symptoms; in one patient the eleventh rib also was resected. At latest review 5 to 34 months postoperatively there has been no recurrence of symptoms

We treated 52 patients with impingement of the anterolateral soft tissues of the ankle by arthroscopic debridement. All had a history of single or multiple inversion injuries, without instability. One half had negative stress radiographs (stable group), while the others were positive (unstable group). Their mean age was 31 years and there were 35 men and 17 women. The results were assessed at a mean follow-up of 30 months. Three patients (6%) had a fair result, while 49 (94%) had an excellent or good outcome. No difference was found in the final results between the two groups (p > 0.05). We conclude that anterolateral impingement of the ankle should be considered in a patient with chronic anterolateral pain after an injury, regardless of the stability of the ankle

Our aim was to evaluate bursal involvement at different stages of the impingement syndrome as judged by conventional histopathological examination and expression of tenascin-C, which is known to reflect active reparative processes in different tissues and disorders. Samples of subacromial bursa were taken from 33 patients with tendinitis, 11 with a partial tear and 18 with a complete tear of the rotator cuff, and from 24 control shoulders. We assessed the expression of tenascin-C, the thickness of the bursa, and the occurrence and degree of fibrosis, vascularity, haemorrhage and inflammatory cells. The expression of tenascin-C was significantly more pronounced in the complete tear group (p < 0.001) than in the partial tear, tendinitis or control groups. It was more pronounced in the tendinitis group than in the control group (p = 0.06), and there was more fibrosis in all the study groups than in the control group. The changes in the other parameters were not equally distinctive. Expression of tenascin-C did not correlate with the conventional histopathological parameters, suggesting that these markers reflect different phases of the bursal reaction. Tenascin-C seems to be a general indicator of bursal reaction, being especially pronounced at the more advanced stages of impingement and this reaction seems to be an essential part of the pathology of impingement at all its stages

A total of 159 patients (84 women and 75 men, mean age of 53 (20 to 87)) with subacromial impingement were randomised to treatment with subacromial injections using lidocaine with one of hyaluronic acid (51 patients), corticosteroid (53 patients) or placebo (55 patients). Patients were followed up for 26 weeks. The primary outcome was pain on a visual analogue score (VAS), and secondary outcomes included the Constant Murley score, shoulder pain score, functional mobility score, shoulder disability questionnaire and pain-specific disability score. The different outcome measures showed similar results. After three, six and 12 weeks corticosteroid injections were superior to hyaluronic acid injections and only at six weeks significantly better than placebo injections. The mean short-term reduction in pain on the VAS score at 12 weeks was 7% (. sd. 2.7; 97.5% confidence interval (CI) 0.207 to 1.55; p = 0.084) in the hyaluronic acid group, 28% (. sd. 2.8; 97.5% CI 1.86 to 3.65; p < 0.001) in the corticosteroid group and 23% (. sd. 3.23; 97.5% CI 1.25 to 3.26; p < 0.001) in the placebo group. At 26 weeks there was a reduction in pain in 63% (32 of 51) of patients in the hyaluronic acid group, 72% (38 of 53) of those in the corticosteroid group and 69% (38 of 55) of those in the placebo group. We were not able to show a convincing benefit from hyaluronic acid injections compared with corticosteroid or placebo injections. Corticosteroid injections produced a significant reduction in pain in the short term (three to 12 weeks), but in the long term the placebo injection produced the best results

We evaluated 67 shoulders in 65 patients who had pain and dysfunction for more than two years after an initial acromioplasty for impingement syndrome without a rotator cuff tear. In addition to a thorough history, physical examination, local anaesthesia injection and any other necessary investigations all patients had arthroscopic evaluation of the shoulder. In 27 shoulders there had been diagnostic errors, and in 28 operative errors; only in 12 had the diagnosis and the operative procedure both been correct. Subsequent operative intervention in patients not receiving worker's compensation benefit had a 75% success rate, whereas in those receiving such benefits the success rate was only 46%

This study examined the relationship between the cross-over sign and the true three-dimensional anatomical version of the acetabulum. We also investigated whether in true retroversion there is excessive femoral head cover anteriorly. Radiographs of 64 hips in patients being investigated for symptoms of femoro-acetabular impingement were analysed and the presence of a cross-over sign was documented. CT scans of the same hips were analysed to determine anatomical version and femoral head cover in relation to the anterior pelvic plane after correcting for pelvic tilt. The sensitivity and specificity of the cross-over sign were 92% and 55%, respectively for identifying true acetabular retroversion. There was no significant difference in total cover between normal and retroverted cases. Anterior and posterior cover were, however, significantly different (p < 0.001 and 0.002). The cross-over sign was found to be sensitive but not specific. The results for femoral head cover suggest that retroversion is characterised by posterior deficiency but increased cover anteriorly

This is a retrospective review of 108 patients who underwent decompressive anterior acromioplasty for chronic impingement in the absence of a full thickness rotator cuff tear. Before operation, all the patients had had shoulder pain for at least one year despite conservative treatment. At operation, the rotator cuff tendons were explored and were intact. Anterior acromioplasty, followed by rehabilitation was successful in 87% of patients. The operation was less successful in women, in those who had diminished movement before operation, who were involved in worker's compensation claims, and whose pain followed direct trauma. Appropriate selection of patients is considered the key to success

We assessed the long-term outcome of open debridement for the treatment of anterior impingement of the ankle in 27 patients. By using preoperative radiographs to group patients according to both the McDermott and the van Dijk scoring system, we assessed the accuracy of these classifications in predicting outcome. The Ogilvie-Harris scoring system, a visual analogue scale of patient satisfaction, the time to return to full activities, and the ability to return to sports determined the clinical outcome. Follow-up radiographs were used to assess the recurrence of osteophytes. We also assessed the incidence of talar osteochondral lesions at surgery. At a mean follow-up of 7.3 years, 23 of 25 patients (92%) without joint-space narrowing had a good or excellent result. Improvement in the Ogilvie-Harris score was seen in all patients. In athletes, 19 of 24 (79%) were able to return to sports at the same level. Two patients with preoperative joint-space narrowing had a poor result. Osteophytes usually recurred and most patients did not feel that the range of dorsiflexion returned to normal, but symptomatic relief allowed most to return to high-level sport. Our results for non-arthritic joints suggest that this is a safe and successful procedure

Symptomatic impingement of the rotator cuff between the humeral head and the coracoid process has been studied and three varieties recognised: idiopathic, iatrogenic and traumatic. In all three the clinical findings consisted of pain in front of the shoulder, referred to the upper arm and forearm, and especially felt during forward flexion and medial rotation; the pain could be reproduced by medial rotation with the arm in 90 degrees of abduction, or by adduction with the shoulder flexed to 90 degrees. Patients were relieved of their symptoms by restoring adequate subcoracoid clearance

Aims

Responsiveness and ceiling effects are key properties of an outcome score. No such data have been reported for the original English version of the International Hip Outcome Tool 12 (iHOT-12) at a follow-up of more than four months. The aim of this study was to identify the responsiveness and ceiling effects of the English version iHOT-12 in a series of patients undergoing hip arthroscopy for intra-articular hip pathology at a minimum of one year postoperatively.

We have carried out a prospective double-blind randomised controlled trial to compare the efficacy of a single subacromial injection of the non-steroidal anti-inflammatory drug, tenoxicam, with a single injection of methylprednisolone in patients with subacromial impingement. A total of 58 patients were randomly allocated into two groups. Group A received 40 mg of methylprednisolone and group B 20 mg of tenoxicam as a subacromial injection along with lignocaine. The Constant-Murley shoulder score was used as the primary outcome measure and the Disability of Arm, Shoulder and Hand (DASH) and the Oxford Shoulder Score (OSS) as secondary measures. Six weeks after injection the improvement in the Constant-Murley score was significantly greater in the methylprednisolone group (p = 0.003) than in the tenoxicam group. The improvement in the DASH score was greater in the steroid group and the difference was statistically significant and consistent two (p < 0.01), four (p < 0.01) and six weeks (p < 0.020) after the injection. The improvement in the OSS was consistently greater in the steroid group than in the tenoxicam group. Although the difference was statistically significant at two (p < 0.001) and four (p = 0.003) weeks after the injection, it was not at six weeks (p = 0.055). Subacromial injection of tenoxicam does not offer an equivalent outcome to subacromial injection of corticosteroid at six weeks. Corticosteroid is significantly better than tenoxicam for improving shoulder function in tendonitis of the rotator cuff after six weeks

We reviewed 17 patients after arthroscopic resection for anterior impingement in the ankle. All had had painful limitation of dorsiflexion which had failed to respond to conservative treatment. Review at an average of 39 months showed very significant improvements in levels of pain, swelling, stiffness, limping and activity. There was a significant improvement in the range of dorsiflexion but not of plantar flexion. One poor result was due to a superficial infection, and two other patients had residual numbness of the foot which persisted for several months

Subacromial decompression was performed arthroscopically on 65 patients who were evaluated two to five years after the procedure. None had full thickness rotator cuff tears. Patients with partial thickness cuff tears were included in this study in order to allow comparison of arthroscopic acromioplasty with open acromioplasty for stage II impingement. On the UCLA shoulder rating scale, 89% of the cases in this study achieved a satisfactory result. These results compare favourably with those reported following open acromioplasty. The arthroscopic procedure is technically demanding. When properly performed in patients with appropriate indications, hospitalisation is brief, return to activities is rapid, there is little risk of deltoid muscle complications, and the results are lasting

We assessed the predictive value of the macroscopic and detailed microscopic appearance of the coracoacromial ligament, subacromial bursa and rotator-cuff tendon in 20 patients undergoing subacromial decompression for impingement in the absence of full-thickness tears of the rotator cuff. Histologically, all specimens had features of degenerative change and oedema in the extracellular matrix. Inflammatory cells were seen, but there was no evidence of chronic inflammation. However, the outcome was not related to cell counts. At three months the mean Oxford shoulder score had improved from 29.2 (20 to 40) to 39.4 (28 to 48) (p < 0.0001) and at six months to 45.5 (36 to 48) (p < 0.0001). At six months, although all patients had improved, the seven patients with a hooked acromion had done so to a less extent than those with a flat or curved acromion judged by their mean Oxford shoulder scores of 43.5 and 46.5 respectively (p = 0.046). All five patients with partial-thickness tears were within this group and demonstrated less improvement than the patients with no tear (mean Oxford shoulder scores 43.2 and 46.4, respectively, p = 0.04). These findings imply that in the presence of a partial-thickness tear subacromial decompression may require additional specific treatment to the rotator cuff if the outcome is to be improved further

We performed open acromioplasty for intractable impingement syndrome on 96 shoulders (93 patients) with an intact rotator cuff. All the shoulders were examined by ultrasound after a mean interval of nine years. Those showing pathological findings, a poor or fair subjective result, or deterioration of the primary excellent outcome had MRI and/or arthrography. The mean Constant score for the affected shoulders was 70 points and that for 48 non-involved, symptom-free shoulders, 84 points. The subjective outcome was excellent in 45, good in 24, fair in 18 and poor in 9 shoulders. Complete tears were found in 12 shoulders and partial tears in seven. A total of 14 shoulders was symptom-free after acromioplasty, but after an average of five years became painful again and showed deterioration. Of these, six had complete tears and four partial tears of the cuff. The tear rate was 4% in shoulders initially judged to be excellent, 25% in good, 33% in fair and 55% in poor shoulders. The tear rate was 71% in shoulders which subsequently deteriorated. The incidence was higher in men (25%) than in women (11%). We conclude that a tear of the rotator cuff may appear after acromioplasty, although there was no evidence of a tear at the time of operation. This is usually the reason for deterioration in a shoulder with an initially good operative outcome

The benefit of arthroscopy of the hip in the treatment of femoroacetabular impingement (FAI) in terms of quality of life (QoL) has not been reported. We prospectively collected data on 612 patients (257 women (42%) and 355 men (58%)) with a mean age at the time of surgery of 36.7 years (14 to 75) who underwent arthroscopy of the hip for FAI under the care of a single surgeon. The minimum follow-up was one year (mean 3.2 years (1 to 7)). The responses to the modified Harris hip score were translated using the Rosser Index Matrix in order to provide a QoL score. The mean QoL score increased from 0.946 (-1.486 to 0.995) to 0.974 (0.7 to 1) at one year after surgery (p < 0.001). The mean QoL score in men was significantly higher than in women, both before and one year after surgery (both p < 0.001). However, the mean change in the QoL score was not statistically different between men and women (0.02 (-0.21 to 0.27) and 0.04 (-0.16 to 0.87), respectively; p = 0.12). Linear regression analysis revealed that the significant predictors of a change in QoL score were pre-operative QoL score (p < 0.001) and gender (p = 0.04). The lower the pre-operative score, the higher the gain in QoL post-operatively (ρ = -0.66; p < 0.001). One year after surgery the QoL scores in the 612 patients had improved in 469 (76.6%), remained unchanged in 88 (14.4%) and had deteriorated in 55 (9.0%).

The usual causes of pain after total knee replacement are well known, but there are a small number of patients in whom its aetiology is obscure. We report three patients with a specific pain syndrome caused by hypertrophic fibrous tissue in the intercondylar notch. Excision of this tissue relieved the symptoms completely.

Aims. Computer-assisted 3D preoperative planning software has the potential to improve postoperative stability in total hip arthroplasty (THA). Commonly, preoperative protocols simulate two functional positions (standing and relaxed sitting) but do not consider other common positions that may increase postoperative impingement and possible dislocation. This study investigates the feasibility of simulating commonly encountered positions, and positions with an increased risk of impingement, to lower postoperative impingement risk in a CT-based 3D model. Methods. A robotic arm-assisted arthroplasty planning platform was used to investigate 11 patient positions. Data from 43 primary THAs were used for simulation. Sacral slope was retrieved from patient preoperative imaging, while angles of hip flexion/extension, hip external/internal rotation, and hip abduction/adduction for tested positions were derived from literature or estimated with a biomechanical model. The hip was placed in the described positions, and if impingement was detected by the software, inspection of the impingement type was performed. Results. In flexion, an overall impingement rate of 2.3% was detected for flexed-seated, squatting, forward-bending, and criss-cross-sitting positions, and 4.7% for the ankle-over-knee position. In extension, most hips (60.5%) were found to impinge at or prior to 50° of external rotation (pivoting). Many of these impingement events were due to a prominent ischium. The mean maximum external rotation prior to impingement was 45.9° (15° to 80°) and 57.9° (20° to 90°) prior to prosthetic impingement. No impingement was found in standing, sitting, crossing ankles, seiza, and downward dog. Conclusion. This study demonstrated that positions of daily living tested in a CT-based 3D model show high rates of impingement. Simulating additional positions through 3D modelling is a low-cost method of potentially improving outcomes without compromising patient safety. By incorporating CT-based 3D modelling of positions of daily living into routine preoperative protocols for THA, there is the potential to lower the risk of postoperative impingement events. Cite this article: Bone Jt Open 2023;4(6):416–423

Aims. Iliopsoas impingement occurs in 4% to 30% of patients after undergoing total hip arthroplasty (THA). Despite a relatively high incidence, there are few attempts at modelling impingement between the iliopsoas and acetabular component, and no attempts at modelling this in a representative cohort of subjects. The purpose of this study was to develop a novel computational model for quantifying the impingement between the iliopsoas and acetabular component and validate its utility in a case-controlled investigation. Methods. This was a retrospective cohort study of patients who underwent THA surgery that included 23 symptomatic patients diagnosed with iliopsoas tendonitis, and 23 patients not diagnosed with iliopsoas tendonitis. All patients received postoperative CT imaging, postoperative standing radiography, and had minimum six months’ follow-up. 3D models of each patient’s prosthetic and bony anatomy were generated, landmarked, and simulated in a novel iliopsoas impingement detection model in supine and standing pelvic positions. Logistic regression models were implemented to determine if the probability of pain could be significantly predicted. Receiver operating characteristic curves were generated to determine the model’s sensitivity, specificity, and area under the curve (AUC). Results. Highly significant differences between the symptomatic and asymptomatic cohorts were observed for iliopsoas impingement. Logistic regression models determined that the impingement values significantly predicted the probability of groin pain. The simulation had a sensitivity of 74%, specificity of 100%, and an AUC of 0.86. Conclusion. We developed a computational model that can quantify iliopsoas impingement and verified its accuracy in a case-controlled investigation. This tool has the potential to be used preoperatively, to guide decisions about optimal cup placement, and postoperatively, to assist in the diagnosis of iliopsoas tendonitis. Cite this article: Bone Jt Open 2023;4(1):3–12

Aims. The aim of this study was to identify the optimal lip position for total hip arthroplasties (THAs) using a lipped liner. There is a lack of consensus on the optimal position, with substantial variability in surgeon practice. Methods. A model of a THA was developed using a 20° lipped liner. Kinematic analyses included a physiological range of motion (ROM) analysis and a provocative dislocation manoeuvre analysis. ROM prior to impingement was calculated and, in impingement scenarios, the travel distance prior to dislocation was assessed. The combinations analyzed included nine cup positions (inclination 30-40-50°, anteversion 5-15-25°), three stem positions (anteversion 0-15-30°), and five lip orientations (right hip 7 to 11 o’clock). Results. The position of the lip changes the ROM prior to impingement, with certain combinations leading to impingement within the physiological ROM. Inferior lip positions (7 to 8 o’clock) performed best with cup inclinations of 30° and 40°. Superior lip positions performed best with cup inclination of 50°. When impingement occurs in the plane of the lip, the lip increases the travel distance prior to dislocation. Inferior lip positions led to the largest increase in jump distance in a posterior dislocation provocation manoeuvre. Conclusion. The lip orientation that provides optimal physiological ROM depends on the orientation of the cup and stem. For a THA with stem anteversion 15°, cup inclination 40°, and cup anteversion 15°, the optimal lip position was posterior-inferior (8 o’clock). Maximizing jump distance prior to dislocation while preventing impingement in the opposite direction is possible with appropriate lip positioning. Cite this article: Bone Joint Res 2023;12(9):571–579

Aims. The aim of this study was to evaluate the suitability of the tapered cone stem in total hip arthroplasty (THA) in patients with excessive femoral anteversion and after femoral osteotomy. Methods. We included patients who underwent THA using Wagner Cone due to proximal femur anatomical abnormalities between August 2014 and January 2019 at a single institution. We investigated implant survival time using the endpoint of dislocation and revision, and compared the prevalence of prosthetic impingements between the Wagner Cone, a tapered cone stem, and the Taperloc, a tapered wedge stem, through simulation. We also collected Oxford Hip Score (OHS), visual analogue scale (VAS) satisfaction, and VAS pain by postal survey in August 2023 and explored variables associated with those scores. Results. Of the 58 patients (62 hips), two (two hips) presented with dislocation or reoperation, and Kaplan-Meier analysis indicated a five-year survival rate of 96.7% (95% CI 92.4 to 100). Mean stem anteversion was 35.2° (SD 18.2°) for the Taperloc stem and 29.8° (SD 7.9°) for the Wagner Cone stem; mean reduction from Taperloc to Wagner Cone was 5.4° (SD 18.8°). Overall, 55 hips (52 patients) were simulated, and the prevalence of prosthetic impingement was lower for the Wagner Cone (5.5%, 3/55) compared with the Taperloc (20.0%, 11/55) stem, with an odds ratio of 0.20 (p = 0.038). Among the 33 respondents to the postal survey (36 hips), the mean scores were VAS pain 10.9, VAS satisfaction 86.9, and OHS 44.7. A multivariable analysis revealed that reduction of stem anteversion from Taperloc to Wagner Cone was more favourable for VAS pain (p = 0.029) and VAS satisfaction (p = 0.002). Conclusion. The mid-term survival rate for THA using the Wagner Cone stem was high, which may be supported by a reduction in prosthetic impingement. The reduction in excessive stem anteversion by using a tapered cone stem was associated with reduced pain and increased patient satisfaction. Cite this article: Bone Jt Open 2024;5(10):858–867

Aims. In computer simulations, the shape of the range of motion (ROM) of a stem with a cylindrical neck design will be a perfect cone. However, many modern stems have rectangular/oval-shaped necks. We hypothesized that the rectangular/oval stem neck will affect the shape of the ROM and the prosthetic impingement. Methods. Total hip arthroplasty (THA) motion while standing and sitting was simulated using a MATLAB model (one stem with a cylindrical neck and one stem with a rectangular neck). The primary predictor was the geometry of the neck (cylindrical vs rectangular) and the main outcome was the shape of ROM based on the prosthetic impingement between the neck and the liner. The secondary outcome was the difference in the ROM provided by each neck geometry and the effect of the pelvic tilt on this ROM. Multiple regression was used to analyze the data. Results. The stem with a rectangular neck has increased internal and external rotation with a quatrefoil cross-section compared to a cone in a cylindrical neck. Modification of the cup orientation and pelvic tilt affected the direction of projection of the cone or quatrefoil shape. The mean increase in internal rotation with a rectangular neck was 3.4° (0° to 7.9°; p < 0.001); for external rotation, it was 2.8° (0.5° to 7.8°; p < 0.001). Conclusion. Our study shows the importance of attention to femoral implant design for the assessment of prosthetic impingement. Any universal mathematical model or computer simulation that ignores each stem’s unique neck geometry will provide inaccurate predictions of prosthetic impingement. Cite this article: Bone Joint Res 2021;10(12):780–789

Aims. The purpose of this study was to evaluate the mid-term outcomes of autologous matrix-induced chondrogenesis (AMIC) for the treatment of larger cartilage lesions and deformity correction in hips suffering from symptomatic femoroacetabular impingement (FAI). Methods. This single-centre study focused on a cohort of 24 patients with cam- or pincer-type FAI, full-thickness femoral or acetabular chondral lesions, or osteochondral lesions ≥ 2 cm. 2. , who underwent surgical hip dislocation for FAI correction in combination with AMIC between March 2009 and February 2016. Baseline data were retrospectively obtained from patient files. Mid-term outcomes were prospectively collected at a follow-up in 2020: cartilage repair tissue quality was evaluated by MRI using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Patient-reported outcome measures (PROMs) included the Oxford Hip Score (OHS) and Core Outcome Measure Index (COMI). Clinical examination included range of motion, impingement tests, and pain. Results. A total of 12 hips from 11 patients were included (ten males, one female, mean age 26.8 years (SD 5.0), mean follow-up 6.2 years (SD 5.2 months)). The mean postoperative MOCART score was 66.3 (SD 16.3). None of the patients required conversion to total hip arthroplasty. Two patients had anterior impingement. External hip rotation was moderately limited in four patients. There was a correlation between MOCART and follow-up time (r. s. = -0.61; p = 0.035), but not with initial cartilage damage, age, BMI, or imaging time delay before surgery. PROMs improved significantly: OHS from 37.4 to 42.7 (p = 0.014) and COMI from 4.1 to 1.6 (p = 0.025). There was no correlation between MOCART and PROMs. Conclusion. Based on the reported mid-term results, we consider AMIC as an encouraging treatment option for large cartilage lesions of the hip. Nonetheless, the clinical evidence of AMIC in FAI patients remains to be determined, ideally in the context of randomized controlled trials. Cite this article: Bone Joint J 2024;106-B(5 Supple B):32–39

Aims. Cam and pincer morphologies are potential precursors to hip osteoarthritis and important contributors to non-arthritic hip pain. However, only some hips with these pathomorphologies develop symptoms and joint degeneration, and it is not clear why. Anterior impingement between the femoral head-neck contour and acetabular rim in positions of hip flexion combined with rotation is a proposed pathomechanism in these hips, but this has not been studied in active postures. Our aim was to assess the anterior impingement pathomechanism in both active and passive postures with high hip flexion that are thought to provoke impingement. Methods. We recruited nine participants with cam and/or pincer morphologies and with pain, 13 participants with cam and/or pincer morphologies and without pain, and 11 controls from a population-based cohort. We scanned hips in active squatting and passive sitting flexion, adduction, and internal rotation using open MRI and quantified anterior femoroacetabular clearance using the β angle. Results. In squatting, we found significantly decreased anterior femoroacetabular clearance in painful hips with cam and/or pincer morphologies (mean -11.3° (SD 19.2°)) compared to pain-free hips with cam and/or pincer morphologies (mean 8.5° (SD 14.6°); p = 0.022) and controls (mean 18.6° (SD 8.5°); p < 0.001). In sitting flexion, adduction, and internal rotation, we found significantly decreased anterior clearance in both painful (mean -15.2° (SD 15.3°); p = 0.002) and painfree hips (mean -4.7° (SD 13°); p = 0.010) with cam and/pincer morphologies compared to the controls (mean 7.1° (SD 5.9°)). Conclusion. Our results support the anterior femoroacetabular impingement pathomechanism in hips with cam and/or pincer morphologies and highlight the effect of posture on this pathomechanism. Cite this article: Bone Jt Open 2021;2(11):988–996

The October 2023 Shoulder & Elbow Roundup. 360. looks at: Arthroscopic capsular shift surgery in patients with atraumatic shoulder joint instability: a randomized, placebo-controlled trial; Superior capsular reconstruction partially restores native glenohumeral loads in a dynamic model; Gene expression in glenoid articular cartilage varies in acute instability, chronic instability, and osteoarthritis; Intra-articular injection versus interscalene brachial plexus block for acute-phase postoperative pain management after arthroscopic shoulder surgery; Level of pain catastrophizing rehab in subacromial impingement: secondary analyses from a pragmatic randomized controlled trial (the SExSI Trial); Anterosuperior versus deltopectoral approach for primary reverse total shoulder arthroplasty: a study of 3,902 cases from the Dutch National Arthroplasty Registry with a minimum follow-up of five years; Assessment of progression and clinical relevance of stress-shielding around press-fit radial head arthroplasty: a comparative study of two implants; A number of modifiable and non-modifiable factors increase the risk for elbow medial ulnar collateral ligament injury in baseball players: a systematic review