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

Introduction. Impingement of total hip arthroplasties (THAs) has been reported to cause rim damage of polyethylene liners, and in some instances has led to dislocation and/or mechanical failure of liner locking mechanisms in modular designs. Elevated rim liners are used to improve stability and reduce the risk of dislocation, however they restrict the possible range of motion of the joint, and retrieval studies have found impingement related damage on lipped liners. The aim of this study was to develop a tool for assessing the occurrence of impingement under different activities, and use it to evaluate the effects a lipped liner and position of the lip has on the impingement-free range of motion. MATERIALS & METHOD. A geometrical model incorporated a hemi-pelvis and femur geometries of one individual with a THA (DePuy Pinnacle® acetabular cup with neutral and lipped liners; size 12 Corail® stem with 32mm diameter head) was created in SOLIDWORKS (Dassault Systèmes). Joint motions were taken from kinematic data of activities of daily living that were associated with dislocation of THA, such as stooping to pick an object off the floor and rolling over. The femoral component was positioned to conform within the geometry of the femur, and the acetabular component was orientated in a clinically acceptable position (45° inclination and 20° anteversion). Variation in orientation of the apex of the lip was investigated by rotating about the acetabular axes from the superior (0°) in increments of 45° (0°−315°), and compared to a neutral liner. Results. When a lipped liner was used, implant (neck on acetabular rim) impingement was found to occur when performing sit-to-stand from a normal seat, leg cross and pivot, whereas no impingement occurred with a neutral liner. The presence and position of the lip reduced the impingement-free range of motion, compared to the neutral liner. Impingement occurred when the lip was positioned superiorly and anteriorly, when performing most of the activities that were prone to posterior dislocation, and posteriorly, posterior-superiorly and posterior-inferiorly when performing activities prone to anterior dislocation. During sit-to-stand from a normal seat no impingement occurred when a lipped or neutral liner was used. Bone impingement was observed when the performing the roll activity with both lipped and neutral liners. DISCUSSION. Impingement was observed more with lipped liners compared to neutral liners, this agrees with the findings of some clinical studies. The results indicate that the positioning of the lip influences the possible range of impingement-free motion. Considering this and the improved joint stability of using a lipped liner, a balance is required to achieve an optimal range of motion without increasing the risk of dislocation. This tool could potentially to be used to optimise lipped liner design and position, and could assist with the liner selection for patients based on their activities

Introduction. Instability continues to be the number one reason for revision in primary total hip arthroplasty (THA). Commonly, impingement precedes dislocation, inducing a levering out the prosthetic head from the liner. Impingement can be prosthetic, bony or soft tissue, depending on component positioning and anatomy. The aim of this virtual study was to investigate whether bony or prosthetic impingement occurred first in well positioned THAs, with the hip placed in deep flexion and hyperextension. Methods. Twenty-three patients requiring THA were planned for a TriFit/Trinity ceramic-on-poly cementless construct using the OPS. TM. dynamic planning software (Corin, UK). The cups were sized to best fit the anatomy, medialised to sit on the acetabular fossa and orientated at 45° inclination and 25° anteversion when standing. Femoral components and head lengths were then positioned to reproduce the native anteversion and match the contralateral leg length and offset. The planned constructs were flexed and internally rotated until anterior impingement occurred in deep flexion [Fig. 1]. The type (bony or prosthetic), and location, of impingement was then recorded. Similarly, the hips were extended and externally rotated until posterior impingement occurred, and the type and location of impingement recorded [Fig. 2]. Patients with minimal pre-operative osteophyte were selected as a best-case scenario for bony impingement. Results. 6/23 (26%) patients were planned with only a 32mm articulation (<50mm cup size), with the remaining 17 patients all planned with both 32mm and 36mm articulations (≥50mm cup size). Anterior impingement was 26% prosthetic and 74% bony with the 32mm articulations, and 100% bony with the 36mm articulations. Bony impingement in deep flexion was exclusively anterior neck on anterior inferior iliac spine. Posterior impingement was 57% prosthetic and 43% bony with the 32mm articulations, and 41% prosthetic and 59% bony with the 36mm articulations. Bony impingement in hyperextension was exclusively lesser trochanter (LT) on ischium. Of the patients planned with both 32mm and 36mm articulations, there was a 14% increase in prosthetic impingement when a 32mm head was planned (35% and 21% respectively). Discussion. Impingement in THA usually precedes dislocation and should be avoided with appropriate component positioning. We found that in hyperextension, prosthetic and bony impingement were equally common. In deep flexion, impingement was almost exclusively bony. Further studies should investigate the effects of stem version, cup orientation, liner design, cup depth, native offset and retained osteophytes on the type of impingement in THA. For any figures or tables, please contact the authors directly

Abstract. Objectives. Impingement of total hip replacements (THRs) can cause rim damage of polyethylene liners, and lead to dislocation and/or mechanical failure of liner locking mechanisms[1]. A geometric model of a THR in situ was previously developed to predict impingement for different component orientations and joint motions of activities[2]. However, the consequence of any predicted impingement is unknown. This study aimed to develop an in-vitromethod to investigate the effects of different impingement scenarios. Method. A ProSim electro-mechanical single-station hip simulator (Simulation Solutions) was used, and the 32mm diameter metal-on-polyethylene THRs (DePuy Synthes) were assessed. The THR was mounted in an inverted orientation, and the input (motion and loading) applied simulated a patient stooping over to pick an object from the floor[3]. The impingement severity was varied by continuing motion past the point of impingement by 2.5° or 5°, and compressive load applied in the medial-lateral direction was varied from 100N to 200N. Each test condition was applied for 40,000 cycles (n=3). Rim penetration was assessed using a CMM and component separation was measured during the tests. Results. Varying the impingement severity from 2.5° to 5° increased rim penetration two-fold (by >0.05mm) and increased medial-lateral component separation three-fold (by >0.3mm) (both p<0.001). Increasing the medial-lateral load had less effect on the rim penetration and component separation, with exception of rim penetration with the higher impingement severity condition. Conclusion. The impingement severity influenced the medial-lateral component separation, suggesting that increasing the impingement severity could increase the risk of dislocation. The impingement severity, which could be predicted from geometric modelling, was also found to significantly affect rim penetration, meaning this method could be used alongside geometric modelling to predict impingement severity in a range of scenarios. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest

Femoroacetabular Impingement (FAI) syndrome, characterised by abnormal hip contact causing symptoms and osteoarthritis, is measured using the International Hip Outcome Tool (iHOT). This study uses machine learning to predict patient outcomes post-treatment for FAI, focusing on achieving a minimally clinically important difference (MCID) at 52 weeks. A retrospective analysis of 6133 patients from the NAHR who underwent hip arthroscopic treatment for FAI between November 2013 and March 2022 was conducted. MCID was defined as half a standard deviation (13.61) from the mean change in iHOT score at 12 months. SKLearn Maximum Absolute Scaler and Logistic Regression were applied to predict achieving MCID, using baseline and 6-month follow-up data. The model's performance was evaluated by accuracy, area under the curve, and recall, using pre-operative and up to 6-month postoperative variables. A total of 23.1% (1422) of patients completed both baseline and 1-year follow-up iHOT surveys. The best results were obtained using both pre and postoperative variables. The machine learning model achieved 88.1% balanced accuracy, 89.6% recall, and 92.3% AUC. Sensitivity was 83.7% and specificity 93.5%. Key variables determining outcomes included MCID achievement at 6 months, baseline iHOT score, 6-month iHOT scores for pain, and difficulty in walking or using stairs. The study confirmed the utility of machine learning in predicting long-term outcomes following arthroscopic treatment for FAI. MCID, based on the iHOT 12 tools, indicates meaningful clinical changes. Machine learning demonstrated high accuracy and recall in distinguishing between patients achieving MCID and those who did not. This approach could help early identification of patients at risk of not meeting the MCID threshold one year after treatment

Aims. Femoroacetabular Junction Impingement (FAI) describes abnormalities in the shape of the femoral head–neck junction, or abnormalities in the orientation of the acetabulum. In the short term, FAI can give rise to pain and disability, and in the long-term it significantly increases the risk of developing osteoarthritis. The Femoroacetabular Impingement Trial (FAIT) aims to determine whether operative or non-operative intervention is more effective at improving symptoms and preventing the development and progression of osteoarthritis. . Methods. FAIT is a multicentre superiority parallel two-arm randomised controlled trial comparing physiotherapy and activity modification with arthroscopic surgery for the treatment of symptomatic FAI. Patients aged 18 to 60 with clinical and radiological evidence of FAI are eligible. Principal exclusion criteria include previous surgery to the index hip, established osteoarthritis (Kellgren–Lawrence ≥ 2), hip dysplasia (centre-edge angle < 20°), and completion of a physiotherapy programme targeting FAI within the previous 12 months. Recruitment will take place over 24 months and 120 patients will be randomised in a 1:1 ratio and followed up for three years. The two primary outcome measures are change in hip outcome score eight months post-randomisation (approximately six-months post-intervention initiation) and change in radiographic minimum joint space width 38 months post-randomisation. ClinicalTrials.gov: NCT01893034. Cite this article: Bone Joint Res 2014;3:321–7

The primary treatment goal for patients with femoroacetabular impingement syndrome, a common hip condition in athletes, is to improve pain and function. In selected patients, in the short term following intervention, arthroscopic hip surgery is superior to a pragmatic NHS- type physiotherapy programme. Here, we report the three-year follow-up results from the FemoroAcetabular Impingement Trial (FAIT), comparing arthroscopic hip surgery with physiotherapy in the management of patients with femoroacetabular impingement (FAI) syndrome. Two-group parallel, assessor-blinded, pragmatic randomised controlled study across seven NHS England sites. 222 participants aged 18 to 60 years with FAI syndrome confirmed clinically and radiologically were randomised (1:1) to receive arthroscopic hip surgery (n = 112) or physiotherapy and activity modification (n = 110). We previously reported on the hip outcome score at eight months. The primary outcome measure of this study was minimum Joint Space Width (mJSW) on Anteroposterior Radiograph at 38 months post randomisation. Secondary outcome measures included the Hip Outcome Score and Scoring Hip Osteoarthritis with MRI (SHOMRI) score. Minimum Joint Space Width data were available for 101 participants (45%) at 38 months post randomisation. Hip outcome score and MRI data were available for 77% and 62% of participants respectively. mJSW was higher in the arthroscopy group (mean (SD) 3.34mm (1.01)) compared to the physiotherapy group (2.99mm (1.33)) at 38 months, p=0.017, however this did not exceed the minimally clinically important difference of 0.48mm. SHOMRI score was significantly lower in the arthroscopy group (mean (SD) 9.22 (11.43)) compared to the physiotherapy group (22.76 (15.26)), p-value <0.001. Hip outcome score was higher in the arthroscopy group (mean (SD) 84.2 (17.4)) compared with the physiotherapy group (74.2 (21.9)), p-value < 0.001). Patients with FAI syndrome treated surgically may experience slowing of osteoarthritisprogression and superior pain and function compared with patients treated non- operatively

Abstract. Objectives. Impingement in total hip replacements (THRs), including bone-on-bone impingement, can lead to complications such as dislocation and loosening. The aim of this study was to investigate how the location of the anterior inferior iliac spine (AIIS) affected the range of motion before impingement. Methods. A cohort of 25 CT scans (50 hips) were assessed and nine hips were selected with a range of AIIS locations relative to the hip joint centre. The selected CT Scans were converted to solid models (ScanIP) and THR components (DePuy Synthes) were virtually implanted (Solidworks). Flexion angles of 100⁰, 110⁰, and 120⁰ were applied to the femur, each followed by internal rotation to the point of impingement. The lateral, superior and anterior extent of the AIIS from the Centre of Rotation (CoR) of the hip was measured and its effect on the range of motion was recorded. Results. There was found to be a significant (p<0.05) inverse relationship between the ROM of the THR and the lateral measure of the AIIS. Of the three measures, the lateral AIIS measure showed the strongest relationship with ROM to impingement (R=0.73) with the anterior and superior measures resulting in R values of 0.41 and 0.56 respectively. For every millimetre lateral the AIIS location, there was typically a loss of 1.2° of range of motion. With increasing lateralisation, the AIIS was positioned more directly over the femur, thereby reducing the ROM in the THR during high flexion positions. No soft tissue was included in the models which would have affected the ROM. Conclusions. The results from this study have shown that the lateral measure of the AIIS could be a predictor for bone-on-bone impingement. To build confidence, wider study of AIIS location variation is needed, as well as analysis under impingement prone activities of daily living. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Impingement of total hip replacements (THRs) can cause rim damage of polyethylene liners, and lead to dislocation and/or mechanical failure of liner locking mechanisms[1]. Previous work has focussed on the influence of femoral neck profile on impingement without consideration of neck-shaft angle. This study assessed the occurrence of impingement with two different stem designs (Corail standard [135°] and coxa vara [125°]) under different activities with varying acetabular cup orientation (30° to 70° inclination; 0° to 50° anteversion) using a geometric modelling tool. The tool was created in a computer aided design software programme, and incorporated an individual's hemi-pelvis and femur geometry[3] with a THR (DePuy Synthes Pinnacle. ®. shell and neutral liner; size 12 Corail. ®. standard or coxa vara and 32mm head). Kinematic data of activities associated with dislocation[2], such as stooping to pick an object from the floor was applied and incidences of impingement were recorded. Predicted implant impingement was influenced by stem design. The coxa vara stem was predicted to cause implant impingement less frequently across the range of activities and cup orientations investigated, compared to the standard stem [Fig. 1]. The cup orientations predicted to cause impingement the least frequently were at lower inclination and anteversion angles, relative to the standard stem [Fig. 1]. The coxa vara stem included a collar, while the standard stem was collarless; additional analysis indicated that differences were due to neck angle and not the presence of a collar. This study demonstrated that stem neck-shaft angle is an important variable in prosthetic impingement in THR and surgeons should be aware of this when choosing implants. Future work will consider further implant design and bone geometry variables. This tool has the potential for use in optimising stem design and position and could assist with patient specific stem selection based on an individual's activity profile. For any figures or tables, please contact the authors directly

Introduction: Impingement syndrome has been reported to occur in a proportion of patients (9%) following whiplash injuries to the neck. In this study we aim to examine this finding to establish the association and incidence of subacromial impingement following whiplash injuries to the cervical spine. Method and results: We examined 219 patients who had presented to a single surgeon for a medico-legal report, at an average of 13.8 months (range 1–52) following a whiplash injury to the neck. All patients were assessed for clinical evidence of subacromial impingement. The patients were asked if the symptoms had developed following their neck injury and those with past history of shoulder pain were identified and excluded. 56 patients (26%) had shoulder pain following the injury; of these, 11 (5%) had clinical evidence of impingement syndrome, however in the majority other clinicians had overlooked this. The seatbelt shoulder (driver’s right and front passenger’s left) was involved in 9 (82%) of the cases (p< 0.001). The average age was 38.2 years compared with 57.8 years in those with subacromial impingement (p< 0.05). Impingement is therefore likely to be due to direct trauma from the seatbelt in the older age group with an already compromised subacromial space. Conclusion: It is now established that subacromial impingement occurs following whiplash injuries to the neck. This is however, frequently overlooked and shoulder pain is attributed to pain radiating from the neck. It is important that this is appreciated and patients are specifically examined for signs of impingement so that appropriate treatment can be instigated. Direct trauma from the seatbelt is one likely explanation for this association

Introduction. Femoral neck impingement occurs clinically in total hip replacements (THR) when the acetabular liner articulates against the neck of a femoral stem prosthesis. This may occur in vivo due to factors such as prostheses design, patient anatomical variation, and/or surgical malpositioning, and may be linked to joint instability, unexplained pain, and dislocation. The Standard Test Method for Impingement of Acetabular Prostheses, ASTM F2582 −14, may be used to evaluate acetabular component fatigue and deformation under repeated impingement conditions. It is worth noting that while femoral neck impingement is a clinical observation, relative motions and loading conditions used in ASTM F2582-14 do not replicate in vivo mechanisms. As written, ASTM F2582-14 covers failure mechanism assessment for acetabular liners of multiple designs, materials, and sizes. This study investigates differences observed in the implied and executed kinematics described in ASTM F2582-14 using a Prosim electromechanical hip simulator (Simulation Solutions, Stockport, Greater Manchester) and an AMTI hydraulic 12-station hip simulator (AMTI, Watertown, MA). Method. Neck impingement testing per ASTM F2582-14 was carried out on four groups of artificially aged acetabular liners (per ASTM F2003-15) made from GUR 1020 UHMWPE which was re-melted and cross-linked at 7.5 Mrad. Group A (n=3) and B (n=3) consisted of 28mm diameter femoral heads articulating on 28mm ID × 44mm OD acetabular liners. Group C (n=3) and D (n=3) consisted of 40mm diameter femoral heads articulating on lipped 40mm ID × 56mm OD 10° face changing acetabular liners. All acetabular liners were tested in production equivalent shell-fixtures mounted at 0° initial inclination angle. Femoral stems were potted in resin to fit respective simulator test fixtures. Testing was conducted in bovine serum diluted to 18mg/mL protein content supplemented with sodium azide and EDTA. Groups A and C were tested on a Prosim; Groups B and D were tested on an AMTI. Physical examination and coordination measurement machine (CMM) analyses were conducted on all liners pre-test and at 0.2 million cycle intervals to monitor possible failure mechanisms. Testing was conducted for 1.0 million cycles or until failure. An Abaqus/Explicit model was created to investigate relative motions and contact areas resulting from initial impingement kinematics for each test group. Results. Effects of kinematic differences in the execution of ASTM F2582-14 were observed in the four groups based on simulator type (Figure 1) and liner design. The Abaqus/Explicit FEA model revealed notable differences in relative motions and contact points (Figure 2) between specimen components i.e. acetabular liner, femoral head, and femoral stem throughout range of motion. Acetabular liner angular change within shell-fixtures, rim deformation, crack propagation, and metal-on-metal contact between acetabular shell-fixtures and femoral stems were observed as potential failure mechanisms (Figure 3) throughout testing. These mechanisms varied in severity by group due to differing contact stresses and simulator constraints. Significance. Investigating failure mechanisms caused by altered kinematics of in-vitro neck impingement testing, due to influences of simulator type and acetabular liner design, may aid understanding of failure mechanisms involved when assessing complaints/retrievals and influence future prosthetic designs. For any figures or tables, please contact the authors directly

The majority of patients who develop hip arthritis have a mechanical abnormality of the joint. The structural abnormalities range from instability (DDH) to impingement. Impingement leads to osteoarthritis by chronic damage to the acetabular labrum and adjacent cartilage. In situations of endstage secondary DJD, hip arthroplasty is the most reliable treatment choice. In young patients with viable articular cartilage, joint salvage is indicated. Treatment should be directed at resolving the structural abnormalities that create the impingement. Femoral abnormalities corrected by osteotomy or increased head-neck offset by chondro-osteoplasty creating a satisfactory head-neck offset. This can safely be done via anterior surgical dislocation. The acetabular-labral lesions can be debrided and/or repaired. Acetabular abnormalities should be corrected by “reverse” PAO in those with acetabular retroversion or anterior acetabular debridement in those with satisfactory posterior coverage and a damaged anterior rim. Often combinations of the above are indicated. This talk will also update issues related to hip impingement and joint salvage surgery that have arisen over the past year

Research into the treatment of Femoro-Acetabular Impingement (FAI) has focussed on surgical correction of structural abnormalities and tended to overlook the dynamic process of impingement. The role of Physiotherapy in addressing abnormal hip movement and any resulting effect on the symptoms of FAI remains untested. A pilot study was therefore instigated to evaluate the effect of physiotherapy on pain and function in patients with FAI. 30 adults aged between 18 and 50 years with a diagnosis of symptomatic FAI were recruited. 23 (77%) completed the study. Intervention was 3 months of specialist physiotherapy focused on improving pelvic and proximal femoral control. The control group received routine care. All functional outcomes improved in the Physiotherapy group and this included improvement beyond minimal clinically important difference and measurement error on the Hip Outcome Score. There was marginal improvement in pain in both groups. Results suggest that physiotherapy treatment can improve function in adults with symptomatic FAI. Larger studies are needed to evaluate the role of conservative management in FAI

Background. Rotational acetabular osteotomy (RAO) is an effective treatment option for symptomatic acetabular dysplasia. However, excessive lateral and anterior correction during the periacetabular osteotomy may lead to femoroacetabular impingement. We used preoperative planning software for total hip arthroplasty to perform femoroacetabular impingement simulations before and after rotational acetabular osteotomies. Methods. We evaluated 11 hips in 11 patients with available computed tomography taken before and after RAO. All cases were female and mean age at the time of surgery was 35.9 years. All cases were early stage osteoarthritis without obvious osteophytes or joint space narrowing. Radiographic analysis included the center-edge (CE) angle, Sharp's acetabular angle, the acetabular roof angle, the acetabular head index (AHI), cross-over sign, and posterior wall sign. Acetabular anteversion was measured at every 5 mm slice level in the femoral head using preoperative and postoperative computed tomography. Impingement simulations were performed using the preoperative planning software ZedHip (LEXI, Tokyo, Japan). In brief, we created a three-dimensional model. The range of motion which causes bone-to-bone impingement was evaluated in flexion (flex), abduction (abd), external rotation in flex 0°, and internal rotation in flex 90°. The lesions caused by impingement were evaluated. Results. In the radiographic measurements, the CE angle, Sharp's angle, acetabular roof angle, and AHI all indicated improved postoperative acetabular coverage. The cross-over sign was recognized pre- and postoperatively in each case. Acetabular retroversion appeared in one case before RAO and in three cases after RAO. Preoperatively, there was a tendency to reduce the acetabular anteverison angle in the hips from distal levels to proximal. In contrast, there was no postoperative difference in the acetabular anteversion angle at any level. In our simulation study, bone-to-bone impingement occurred in flex (preoperative/postoperative, 137°/114°), abd (73°/54°), external rotation in flex 0°(34°/43°), and internal rotation in flex 90°(70°/36°). Impingement occurred within internal rotation 45°in flexion 90°in two preoperative and eight postoperative cases. The impingement lesions were anterosuperior of the acetabulum in all cases. Discussion. It is easy to make and assess an impingement simulation using preoperative planning software, and our data suggest the simulation was helpful in a clinical setting, though there were some remaining problems such as approximation of the femoral head center and differences in femur movement between the simulation and reality. In the postoperative simulation there was a tendency to reduce the range of motion in flex, abd, and internal rotation in flex 90°. There was a correlation between acetabular anteversion angle and flex. Since impingement occurred within internal rotation 45°in flexion 90°in eight postoperative simulations, we consider there is a strong potential for an increase in femoroacetabular impingement after RAO

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.

The diagnosis of subacromial impingement of the shoulder is generally a clinical diagnosis, with no well defined diagnostic criteria. A number of tests have been described. Neer and Hawkins signs are the most common with reported sensitivities for subacromial impingement of 75% and 92% respectively. The senior author was taught another impingement test by Mr S Copeland during his Fellowship in Reading, UK. The Copeland Impingement test is an extension of the Neer’s impingement sign, where abduction in the scapula plane with the shoulder in internal rotation causes mid-arc pain which is abolished with abduction in external rotation. In a retrospective study we analysed the clinical data of twenty-nine patients diagnosed with subacromial impingement of the shoulder. The diagnosis was determined by the clinician’s final diagnosis. This was based on the clinical findings and response to a subacromial injection (Neer’s Test). The clinical tests included were: Hawkin’s test, Mid-arc impingement pain, Neer’s sign, Neer’s test and the Copeland impingement test. The sensitivity and specificity of each test was determined and the values statistically analysed for any significance. The Copeland test was the most sensitive, with 95% sensitivity. Using the Wilcoxon’s signed ranks test the Copeland test was significantly more sensitive than the Neer’s and Hawkin’s tests for subacromial impingement. In conclusion the Copeland test is an effective clinical test in the diagnosis of subacromial impingement and more sensitive than the traditional tests

Acetabular rim damge due to rim impingement is frequently found on retrievals and may be associated with increased wear and contact stresses, instability, and implant loosening of total hip replacement devices. Large X3 bearings (> 36mm) from Stryker have increased implant range of motion and improved polyethylene material (sequentially crosslinked and annealed). A hip simulator wear study was performed with and without femoral neck to acetabular rim impingement to determine the wear performance of these new bearings under aggressive impingement conditions. Two sizes of these new components were tested (36mm with 3.9mm thickness and 40mm with 3.8mm thickness) with two standard sized controls (28mm with 7.9mm thickness in X3 and conventional polyethylene. The 36mm component was chosen to be the largest component utilizing the same shell as the standard 28mm size components while the 40mm component was chosen to be the thinnest bearing currently offered. Impingement significantly increased wear for all bearings (p< 0.05) but no cracking or failures of the rim occurred. Wear rates for all X3 bearings were statistically indifferent under each testing condition despite bearing size and thickness. Average wear rates for X3 bearings were 0.3mm3/million cycles (mc) under standard conditions and 3.5mm3/mc under impingement conditions. Average wear rates for conventional bearings were 19.5mm3/mc under standard conditions and 48.3mm3/mc under impingement conditions. Overall the X3 bearings exhibited a 93% reduction in wear under impingement conditions and 99% reduction in wear under standard conditions. Increased bearing range of motion reduces the chance of impingement. This study shows the simulated outcome even if these larger bearings were to impinge. We conclude that these larger X3 bearings exhibits the same wear performance as standard X3 bearings and significantly superior wear performance compared to conventional polyethylene bearings under standard and impingement conditions

Introduction:. Femoro-acetabular impingement reduces the range of motion of the hip joint and is thought to contribute to hip osteoarthritis. Surgical treatments attempt to restore hip motion through resection of bone at the head-neck junction. Due to the broad range of morphologies of FAI, the methodology of osteochondroplasty has been difficult to standardize and often results in unexpected outcomes, ranging from minimal improvement in ROM to excessive head resection with loss of cartilage and even neck fracture. In this study we test whether a standardized surgical plan based on a pre-determined resection path can restore normal anatomy and ROM to the CAM-impinging hip. Methods:. Computer models of twelve femora with classic signs of cam-type FAI were reconstructed from CT scans. The femoral shaft and neck were defined with longitudinal axes and the femoral head by a sphere of best fit. Boundaries defining the maximum extent of anterior resection were constructed: (i) superiorly and inferiorly along the anterior femoral neck at 12:30 and 5:30 on the clock face, approximating the locations of the vascularized synovial folds; (ii) around the head-neck junction along the edge of the articular cartilage; and (iii) at the base of the neck, perpendicular to the neck axis, 20–30 mm lateral to the articular edge. All four boundaries were used to form 3 alternative resection surfaces that provided resection depths of 2 mm (small), 4 mm (medium), and 6 mm (large) at the location of the cam lesion. Solid models of each femur after virtual osteochondroplasty were created by Boolean subtraction of each of the resection surfaces from the original femoral model. For each depth of neck resection, we measured the following: (i) alpha angle, (ii) anterior offset of the head-neck junction, and (iii) volume of bone removed. Before and after each resection, we also measured the maximum internal rotation of the hip in 90° flexion and 0° abduction. Results:. The initial alpha angles of the twelve femora averaged 63.8°, with corresponding average anterior head-neck offset of 5.8 mm and average maximum internal rotation of 16.3°. Impingement prevented one specimen from attaining the initial position of 90° flexion and 0° abduction. Implementation of pre-operative plans demonstrated that normal alpha angles (<55°) could be achieved using resection depths of 2 mm, 4 mm, and 6 mm (small: 48.8°, medium: 40.8°, large: 35.3°). The corresponding changes in internal rotation were +7.7° (to 24.0°; p < 0.001), +11.8° (to 28.1°; p < 0.001), and +14.7° (to 31°; p < 0.001), with anterior offsets of 8.0 mm, 9.9 mm, and 11.2 mm, respectively. The corresponding volume of resected bone ranged from 0.57 cm. 3. to 3.20 cm. 3. . Conclusions:. Our study shows that a standardized method of pre-operative planning may enable surgeons to restore normal hip ROM, alpha angles, and anterior offsets through pre-determined bony resection. This method shows how osteochondroplasty can be customized to each deformity, thus removing only the necessary amount of bone to correct each abnormality. We believe implementation of our boundaries and method will enable surgeons to consistently and quantitatively reproduce and teach osteochondroplasty, and that this method is readily adaptable to computerized machining of the femur

Performance of metal-on-metal (MOM) bearings was of great interest until recently. Major concerns emerged over high incidence of MOM-wear failures and initially there appeared greater risks with MOM total hip arthroplasty (THA) designs compared to resurfacing arthroplasty (RSA). Impingement of the metal neck against the THA cup was likely the differentiating risk. There is a major difference between RSA and THA in (i) size of femoral necks and (ii) risk of THA metal necks impinging on metal cups. For example, a 46mm THA with 12.5mm neck, a 3.68 head:neck (H/N) ratio, provides a suitably large range-of-motion (ROM). In contrast, an RSA patient with retained 31mm size of natural neck would only have H/N = 1.48, indicating even less ROM than a Charnley THA. However, the enigma is that RSA patients have as good or better ROM in majority of clinical studies. We studied this apparent RSA vs THA dilemma by examining MOM retrievals for signs of adverse impingement. We previously described CoCr stripe wear in failed THA bearings, notably alignment of polar and basal wear stripes coincident with the rim profiles of the cups (Clarke 2013). Our governing hypothesis was that RSA patients had to routinely sublux their hips to get ROM comparable to THA. Our THA impingement studies showed polar stripes within 15o of the polar axis in large heads. For the various RSA diameters, we calculated that wear stripes angled 40o from the femoral axis could indicate impingement with no subluxation, whereas smaller angles would indicate routine subluxation of RSA femoral-shell from cup. We compared explanted RSA (N=15) and THA (N=15) bearings representing three vendors (42–54mm diameters). Wear maps and head-stripes were ink-marked for visualization, photography, and analysis. Wear areas were calculated using spherical equations and wear-stripe angles measured by computer graphics. The results showed that RSA femoral shells had wear areas circular in shape with areas varying 1,085- 3,121mm2. These averaged 14% larger than in matched THA heads but statistically significant difference was not proven. Polar stripes were readily identifiable on femoral components, 75% for RSA cases and 100% for THA. These contained identical linear scratches and all were sited within 30o of neck axis, confirming our hypothesis that RSA patients had to sublux their hips to achieve same motion as THA. Examination of cup wear areas revealed all showed ‘edge-loading’, but RSA cups had a significantly greater degree. Retrieval studies are limited by uncontrolled case sources, varied brands, and small numbers. In this study, we were able to match RSA and THA cases by vendor and diameter. The RSA retrievals revealed polar stripes identical to THA by site, topography and inclination to femoral-neck axis. This confirmed our starting hypothesis and explained the large clinical ROM available in RSA patients. The larger wear areas on RSA femoral shells, although not statistically significant, and the larger ‘edge loading’ sites in RSA cups appeared as further support for routine subluxation of femoral-shells during hip impingement

Introduction. Subacromial corticosteroid injection is widely used in the treatment of Subacromial Impingement Syndrome (SIS). There is increasing interest in using ultrasound (US) to improve the accurate placement of injections. This study investigated whether the accuracy of placement of US-guided subacromial corticosteroid injections influences patients' outcome of pain and function. Method. Secondary analysis of data from a 2−2 factorial randomised controlled trial investigating exercise and corticosteroid injection for pain and function in SIS. US-guided injections were delivered according to a pre-defined protocol. Video images were reviewed to categorise accuracy of injection into the subacromial bursa into 3 accuracy groups using pre-defined criteria: 1) not in the subacromial bursa; 2) probably in the subacromial bursa; and 3) definitely in the subacromial bursa. The primary outcome measure was the self-reported Shoulder Pain and Disability Index (SPADI) total score, compared at 6 weeks and 6 months. Secondary outcomes included SPADI pain and function subscales and participant global rating of overall change from baseline. A mixed effects model was used to compare accuracy groups' outcomes at 6 weeks and 6 months, adjusted for baseline covariates. Results. US-guided injection accuracy data were available for 114 participants; with 22 participants in group 1, 21 in group 2 and 71 in group 3. There were no significant differences in mean SPADI scores among the three injection accuracy groups at 6 weeks (group 2 vs. 1: 8.22 (95% CI −4.01, 20.50); group 3 vs. 1: −0.57 (−10.27, 9.13)) and 6 months (group 2 vs. 1: 12.38 (−5.34, 30.10); group 3 vs. 1: 3.10 (−11.04, 17.23)). Similarly, no differences between accuracy groups were seen in SPADI pain, SPADI function or participant global rating of change. Conclusion. The accuracy of US-guided subacromial corticosteroid injection in SIS does not influence clinical response to the injection, questioning the need for guided injections. Larger, adequately powered studies are required to explore this further

Femoroacetabular impingement (FAI) is a condition of the hip where there is a mismatch of the femoral head and hip acetabulum. This mismatch creates abnormal contact between the bones and causes hip pain which can lead to damage, and eventually osteoarthritis of the hip. The diagnosis and treatment of FAI has become one of the most popular clinical scenarios in orthopaedic surgery, with hip arthroscopy procedures increasing exponentially over the past five years. Surgical intervention usually involves correcting the existing deformities by reshaping the ball and socket (“osteoplasty” or “rim trimming”) so that they fit together more easily while repairing any other existing soft tissue damage in the hip joint (e.g. labral repair). Although correction of the misshaped bony anatomy and associated intra-articular soft tissue damage of the hip is thought to appease impingement and improve pain and function, the current evidence is based on small, observational, and low quality studies. A lack of definitive evidence regarding the efficacy of osteochondroplasty in treating FAI fueled the design and execution of the FIRST randomized controlled trial (RCT). FIRST evaluated the impact of surgical correction of the hip impingement morphology with arthroscopic osteochondroplasty versus arthroscopic lavage on pain, function, and quality of life in adults aged 18–50 years diagnosed with non-arthritic FAI at one year.

FIRST was a large definitive RCT (NCT01623843) enrolling patients with FAI requiring surgical intervention across 11 international clinical sites. Participants were randomized to either arthroscopic osteochondroplasty (shaving of bone) or lavage (washing the joint of painful inflammation debris). The primary outcome was patient-reported pain within one year of the initial surgery measured using the Visual Analogue Scale (VAS). Secondary outcomes included function, health utility, and health-related quality of life using several general and hip-centric health questionnaires. An independent, blinded adjudication committee evaluated the quality of surgery, re-operations, and other patient complications. Patients and data analysts were blinded to the treatment groups.

Two-hundred and twenty participants were enrolled into the FIRST trial over a six-year period (pilot phase: N=50, from 2012–2013 and definitive phase: N=170, from 2015–2018) at 11 clinical sites in Canada, Finland, and Denmark. The FIRST results will be released at the ISAKOS annual meeting as follows. The absolute difference in rate of pain reduction between groups was XX (95% CI: YY-YY, p=X). The mean differences of the Short-Form 12 (SF-12, MCS and PCS), Hip Outcome Score (HOS), International Hip Outcome Tool (iHOT-12), and EuroQol 5-Dimensions (EQ-5D) between groups are XX (95% CI: YY-YY, p=X)…, respectively. Reoperations occurred in XX of 220 (X%) patients over the one-year follow up period (OR:XX, 95% CI: YY-YY, p=X) and the patients treated with arthroscopic osteochondroplasty conferred the following risk of reoperation within one-year compared to arthroscopic lavage (RR:XX, 95% CI: YY-YY, p=X).

This RCT represents major international efforts to definitively identify the optimal treatment strategy for FAI. The results of this trial will change practice, being used to prevent chronic hip pain and loss of function caused by hip osteoarthritis.

Most patients presenting with loss of hip motion secondary to FAI have a combination of cam and pincer morphology. In this study, we present a composite index for predicting joint ROM based on anatomic parameters derived from both the femur and acetabulaum using a single reformatted CT slice. Computer models of the hip joint were reconstructed from CT scans of 31 patients with mixed-type FAI (Average alpha angle: 73.6±11.1°, average LCE: 38.9±7.2°). The internal rotation of the hip at impingement was measured at 90° flexion using custom software. With the joint in neutral, a single slice perpendicular to the acetabular rim was taken at the 2 o'clock position. A set of 11 femoral and acetabular parameters measured from this slice were correlated with hip ROM using stepwise logistic regression. Three anatomic parameters provided significant discrimination of cases impinging at <15 and >15 degrees IR: femoral anteversion (28%, p=0.026), the arc of anterior femoral head sphericity (10%, p=0.040), and the LCE in the 2 o'clock plane (10%, p=0.048). This led to the following definition of the Impingement Index: 0.16*(fem version) +0.11*(ant arc)−0.17*(LCE) which correctly classified 82% of cases investigated. None of the traditional parameters (e.g. alpha angle) were significantly correlated with ROM. Our study has identified alternative morphologic parameters that could act as strong predictors of FAI in preoperative assessments. Using this information, each patient's individual risk of impingement may be estimated, regardless of the relative contributions of deformities of the femur and the acetabulum

Introduction. Health Economists in Denmark have recently reported low and delayed return to work for patients treated for Sub-Acromial Impingement syndrome (SAIS) by Arthroscopic Sub-Acromial Decompression (ASAD). Surgeons however are reporting that patients achieve good pain relief and a high standard of activities of daily living (ADL) after surgery. Aim. To evaluate the effectiveness of ASAD for patients with SAIS and correlate clinical outcome with rate of return to work. Methods. Prospective cohort study and retrospective review of data from the Nottingham Shoulder database (presentation: 01/04/2008–30/06/2011). Inclusion criteria: Patients diagnosed clinically with SAIS by an experienced shoulder surgeon, who have failed conservative treatment (physiotherapy and sub-acromial injection), undergoing ASAD. Pre-operative and 6-month follow-up Oxford Shoulder Score (OSS) and Constant Score (CS) were compared. The rates of return to pre-operative level of work were also analysed. Statistical analysis: Wilcoxon signed rank test. Results. 73 patients with OSS (51 also with CS documentation) were included. The improvement in median OSS between pre-operative (24) and 6-month follow-up (39) was +15 (Z = −6.726, ∗∗∗, T=6, r=0.55). The difference in median CS between pre-operative (39) and 6-month follow-up (67) was +28 (Z=−5.435, T=6, r=0.59, ∗∗∗). Improvement in median pain score was +5 (7,12, ∗∗∗) median ADL was +5.5 (10.5,16, ∗∗∗) median ROM was +13 (18,31, ∗∗∗) and median strength was +4 (3,7, ∗∗∗). 76% returned to their pre-operative level of work (mean time = 11.5 weeks post surgery). 79% returned to their pre-operative hobbies (mean time = 11.8 weeks post surgery). Conclusion. There is a significant improvement in OSS and CS, 6 months after ASAD in patients with SAIS who have had previous failed conservative treatment. The rate of return to work was good for these patients in contrast to that reported for Danish patients. (∗∗∗ = p< 0.0001 = Highly statistically significant)

This study presents the results of 60 consecutive hip arthroscopic procedures for the treatment of Acetabulo-Femoral Impingement. The procedures were performed by a single surgeon over a period of 36 months. The learning curve and the evolution of the current technique along with the clinical outcomes are discussed Additionally two new clinical signs of AFI are described, along with the correlation of radiological and arthroscopic findings. Sixty patients underwent hip arthroscopies. The procedures included labral debridement, labral repair, femoral and/or acetabular osteectomies. All patients underwent MRI examination and three-dimensional CT imaging to identify the impingement lesion. Follow up CT scanning was performed to assess the accuracy of the bony resection. Patients were reviewed at three months and subsequently at twelve monthly intervals. All patients participated in completing questionnaires. Post-operatively Modified Harris Hip score improved from 54 to 70, Non-Arthritic hip score improved from 58 to 75, SF12 score improved from 35 to 40. Three patients required a second procedure for further bony resection. One patient underwent a THR within 12 months. Two female patients suffered minor vaginal abrasions. Hip arthroscopy is a demanding procedure. Good clinical results are achieved only when the cause of impingement has been identified and treated

There is little known about how patient socioeconomic status impacts clinical outcomes in hip preservation surgery. The aim of this study was to evaluate the relationship between indices of multiple deprivation, funding provider (NHS Funded or Private Funded) and clinical outcomes following surgery for femoroacetabular impingement (FAI)

The study analysed the data of 5590 patients recorded in the NAHR who underwent primary hip arthroscopic treatment for FAI between November 2013 and July 2023. Records were matched to the UK National index of multiple deprivation using the lower layer super output area. Using iHOT12 score, patient reported outcome measures were analysed at base line and 1 year following surgery.

2358 records were matched to LLSOA deciles. Between the lowest (most deprived) 3 deciles and the highest (least deprived) the average baseline iHOT12 score was 28.98 (n=366) and 35.33 (n=821). The proportion of patients receiving treatment through NHS funding compared to independent funding for the most deprived, 292 (90%) 37 (10%) respectively compared to the least deprived 515 (70%) and 244 (30%) respectively. At 1year, iHOT12 scores for each group were 51.64 (29.1 SD) compared to 61.5 (28.06 SD) respectively.

The study demonstrates that patients from lower socioeconomic backgrounds had poorer baseline and one-year post-surgery iHOT12 scores compared to those from higher socioeconomic strata. Furthermore, a higher reliance on NHS funding was observed among the most deprived, while more affluent patients predominantly opted for private funding. These findings underscore the significant influence of socioeconomic status on both the quality of healthcare received and recovery outcomes in hip preservation surgery, calling attention to the need for more equitable healthcare solutions.

Risk of impingement after total hip resurfacing arthroplasty may be great because femoral head-neck unit is preserved and there is little flexibility to adjust limb length and femoral offset, but this potentially worrisome phenomenon has been rarely reported. Impingement between femoral neck and acetabular cup was observed in a cohort of patients who underwent contemporary total hip resurfacing arthroplasty. We then questioned whether patient demographics, component features or suboptimal position of components would be risk factors for impingement. We reviewed a consecutive series of 51 patients (61 hips) who underwent contemporary total hip resurfacing arthroplasty. The mean age at the time of the index arthroplasty was 38 years (18 to 64). The most common diagnosis leading to the total hip resurfacing arthroplasty was osteonecrosis of the femoral head in 41 hips (67%). All the procedures were performed by single surgeon through an anterolateral approach. All the patients were assessed clinically and radiographically at a mean of 32 months (24 to 53) postoperatively. Femoro-acetabular cup impingement, defined as the presence of bony spur at the femoral neck corresponding to abutment site of the metallic cup, was observed in seven of the 61 hips (11.5%). Of these, five patients reported limitation of activities due to groin pain. The average postoperative Harris hip score of impingement hips was inferior to those of non-impingement hips (p = 0.004). No significant difference was detected between the impingement hips and non-impingement hips with regard to of patient demographics, component features and radiographic measurements including cup inclination, cup version, femoral component version, anterior femoral offset, stem-shaft angle, femoral offset and limb length discrepancy. Our multivariate analysis revealed that only acetabular cup uncoverage ratio had a significant association with femoro-acetabular cup impingement (p = 0.04, odds ratio 1.385 [95% CI, 1.014 – 1.891]). There was no aseptic loosening of components or femoral neck fracture. We found a high incidence of impingement between retained femoral neck and metallic acetabular cup after contemporary total hip resurfacing arthroplasty in association with an increased acetabular cup uncoverage ratio. As patients with femoro-acetabular cup impingement showed inferior clinical results, it is crucial to avoid excessive protrusion of acetabular cup beyond bony margin by proper selection of acetabular component size and appropriate positioning

Cam-type femoroacetabular impingement is caused by bone excess on the femoral neck abutting the acetabular rim. This can cause cartilage and labral damage due to increased contact pressure as the cam moves into the acetabulum. However, the damage mechanism and the influence of individual mechanical factors (such as sliding distance) are poorly understood. The aim of this study was to identify the cam sliding distance during impingement for different activities in the hip joint.

Motion data for 12 different motion activities from 18 subjects, were applied to a hip shape model (selected as most likely to cause damage, anteriorly positioned with a maximum alpha angle of 80°). The model comprised of a pointwise representation of the acetabular rim and points on the femoral head and neck where the shape deviated from a sphere (software:Matlab).

The movement of each femoral point was tracked in 3D while an activity motion was applied, and impingement recorded when overlap between a cam point and the acetabular rim occurred. Sliding distance was recorded during impingement for each relevant femoral point.

Angular sliding distances varied for different activities. The highest mean (±SD) sliding distance was for leg-crossing (42.62±17.96mm) and lowest the trailing hip in golf swing (2.17±1.11mm). The high standard deviation in the leg crossing sliding distances, indicates subjects may perform this activity in a different manner.

This study quantified sliding distance during cam impingement for different activities. This is an important parameter for determining how much the hip moves during activities that may cause damage and will provide information for future experimental studies.

Some military personnel are having Femoral Acetabular Impingement (FAI) surgery. The use of the alpha angle (AA) to help assess the diagnosis is common. Currently there are no standardised values available across a asymptomatic pre-arthritic population. Retrospective analysis of 200 consecutive individuals (400 hip joints) with ages 20 to 50, who had a CT performed between 1 Apr 2011 and 29 Nov 2011 due to abdominal pathology. The AA of Notzli was measured on the axial view. The mean AA value was 53.5 (95%CI 1.30) for Right hips and 53.4 (95% CI 1.31) for the left. In age 20–30 Right 52.6 (95%CI 3.5) the Left 52.0 (95%CI 2.9), 31–40 Right 53.9 (95%CI 2.5) Left 53.4 (95%CI 3.1), 41–50 Right 53.8 (95% CI 1.9) Left 53.2 (95% CI 1.8). Mean male Right 52.9 (95% CI 1.5) Left 53.2 (95%CI 1.9) Female Right 52.5 (95% CI 1.5) Left 49.9 (95% CI 1.6). 144/400 (37%) of patients had angle >55 degrees. Previous literature suggests an AA >55 degrees is diagnostic of FAI, we suggest that the AA is highly variable across age and sex and that >1/3rd of asymptomatic patients will have an AA that was previously regarded as abnormal

Introduction: Abnormal hip morphology, seen with conditions such as slipped capital femoral epiphyses and femoral head necrosis, can lead to repetitive contact between the femoral neck and the acetabular rim. Impingement is a significant cause of hip pain in young adults and may be a mechanism for the development of early osteoarthritis. The senior surgeon has modified a technique to debride the pathology responsible for femoroacetabular impingement through a mini anterior approach, obviating the need to dislocate the hip. We describe this technique and present early clinical outcomes. Method: Between Jan 2006 and June 2008, ‘notchplasty’ for the surgical treatment of femoroacetabular impingement was performed by the senior author (AHN) or directly under his supervision in 38 hips. There were 17 male patients and 21 female patients with an average age of 31 years. Patients have been followed according to a prospective protocol with Oxford and Iowa hip scores obtained pre-operatively, at 3 months and at 1 year. Results: This study is still in progress. Twenty nine patients have had 3 month follow up and 13 of these have now been followed up to one year. Four patients are still less than 3 months post op. Data was unobtainable for 5 patients. 1 patient was excluded from the study. The overall Oxford hip score improved significantly from a mean pre-operative value of 35 to a mean post operative value of 22.9 at 3 months (p< 0.001). The mean score at 1 year increased slightly to 27.3 points but this remains lower than the pre operative average. We report no cases of osteonecrosis. One patient has since been scheduled to undergo resurfacing arthroplasty. Conclusions: The technique described is a new method for managing these patients whilst avoiding the pit-falls of current operative methods. The method avoids detaching the straight head of rectus, thereby tremendously improving postoperative mobilisation. However, the long term benefit of debridement of the head-neck junction for Cam-type femoroacetabular impingement remains to be seen

Abstract

Background: Femoroacetabular Impingement is now considered a prearthritic hip mechanism. It frequently occurs in patients with subtle anatomic abnormalities of the acetabulum, “acetabular retroversion”, which is often difficult to detect on standart xrays. Early diagnosis is of utmost importance as surgical intervention in early stages can most likely halt progression of disease. The objective of this study was to assess wether an easily visible anatomic landmark on an anteroposterior (AP) pelvic xray can be used to screen patients with acetabular retroversion. Methods: The AP pelvic xrays of 1010 patients who were seen at the autors’ institution for a painful hip were reviewed over a 16 year period. Those xrays that did not meet standardized criteria were excluded leaving 149 AP radiographs (298 hips) for analysis. The ‘crossover sign’ (COS), indicative of acetabular retroversion, was recorded for each hip. An easily visible landmark, the prominence of ischial spine (PRIS) into the true pelvis was also recorded and measured. Interobserver and intraobserver variability was assessed. Results: The presence of the PRIS as diagnostic of acetabular retroversion showed a sensitivity of 91% (95%CI 0.85 to 0.95), a specifity of 98% (95% CI 0.94 to 1.00), a positive predictive value of 98% (95%CI 0.94 to 1.00), a negativ predictive value of 92% (95% CI 0.87 to 0.96). There was good and very good intraobserver and interobserver reliability for measurements of the COS and PRIS, respectively. Conclusion: There was excellent sensitivity and positive predictive value of the PRIS as a radiographic marker of acetabular retroversion. The rims of the anterior and posterior walls are sometimes not clearly visible, and even if they are, their translation into a reliable interpretation of acetabular retroversion is difficult. The PRIS sign appears as a good visible prominence on the AP radiographs which can’t be easily confused

Dual Mobility (DM) Total Hip Replacements (THRs), are becoming widely used but function in-vivo is not fully understood.

The aim of this study was to compare the incidence of impingement of a modular dual mobility with that of a standard cup.

A geometrical model of one subject's bony anatomy \[1\] was developed, a THR was implanted with the cup at a range of inclination and anteversion positions (Corail® stem, Pinnacle® cup (DePuy Synthes)). Two DM variants and one STD acetabular cup were modelled. Joint motions were taken from kinematic data of activities of daily living associated with dislocation \[2\] and walking. The occurrence of impingement was assessed for each component combination, orientation and activity. Implant-implant impingement can occur between the femoral neck and the metal or PE liner (DM or STD constructs respectively) or neck-PE mobile liner (DM only).

The results comprise a colour coded matrix which sums the number of impingement events for each cup position and activity and for each implant variant.

Neck-PE mobile liner impingement, occurred for both DM sizes, for all activities, and most cup placement positions indicating that the PE mobile liner is likely to move at the start of all activities including walking.

For all constructs no placement positions avoided neck-metal (DM) or neck-PE liner (STD) impingementevents in all activities. The least number of events occurred at higher inclination and anteversion component positions. In addition to implant-implant impingement, some instances of bone-bone and implant-bone impingement were also observed.

Consistent with DM philosophy, neck-PE mobile liner impingement and liner motion occurred for all activities including walking. Neck-liner impingement frequency was comparable between both DM sizes (metal liner) and a standard cup (PE liner).

Hip Osteoarthritis (HOA) is the most common joint disorder and a major cause of disability in the adult population, leading to total hip replacement (THR). Recently, evidence has mounted for a prominent etiologic role of femoroacetabular impingement (FAI) in the development of early OA in the non-dysplastic hip. FAI is a pathological mechanical process, caused by abnormalities of the acetabulum and/or femur leading to damage the soft tissue structures. FAI can determine chondro-labral damage and groin pain in young adults and can accelerate HOA progression in middle-aged adults.

The aim of the study was to determine if the presence of calcium crystal in synovial fluid (SF) at the time of FAI surgery affects the clinical outcomes to be used as diagnostic and predictive biomarker.

49 patients with FAI undergoing arthroscopy were enrolled after providing informed consent; 37 SFs were collected by arthrocentesis at the time of surgery and 35 analyzed (66% males), median age 35 years with standard deviation (SD) 9.7 and body mass index (BMI) 23.4 kg/m²; e SD 3.

At the time of surgery, chondral pathology using the Outerbridge score, labral pathology and macroscopic synovial pathology based on direct arthroscopic visualization were evaluated. Physical examination and clinical assessment using the Hip disability & Osteoarthritis Outcome Score (HOOS) were performed at the time of surgery and at 6 months of follow up. As positive controls of OA signs, SF samples were also collected from cohort of 15 patients with HOA undergoing THR and 12 were analysed.

45% FAI patients showed CAM deformity; 88% presented labral lesion or instability and 68% radiographic labral calcification. 4 patients out of 35 showed moderate radiographic signs of OA (Kellegren-Lawrence score = 3). Pre-operative HOOS median value was 61.3% (68.10-40.03) with interquartile range (IQR) of 75-25% and post-operative HOOS median value 90% with IQR 93.8-80.60. In both FAI and OA patients the calcium crystal level in SFs negatively correlated with glycosaminoglycan (component of the extracellular matrix) released, which is a marker of cartilage damage (Spearman rho=-0.601, p<0.001).

In FAI patients a worst articular function after surgery, measured with the HOOS questionnaire, was associated with both acetabular and femoral chondropathy and degenerative labral lesion. Moreover, radiographic labral calcification was also significantly associated with pain, worst articular function and labral lesion. Calcium crystal level in SFs was associated with labral lesions and OA signs.

We concluded that the levels of calcium crystals in FAI patients are correlated with joint damage, OA signs and worst post-operative outcome. The presence of calcium crystals in SF of FAI patients might be a potential new biomarker that might help clinicians to make an early diagnosis, evaluate disease progression and monitor treatment response.

Purpose

The purpose of this retrospective study was to investigate the acetabular morphology of pincer impingement hips in order to better understand damage pattern in these patients. We compared MRI measurements made at different postions from anterior to posterior on the acetbulum in patients with pure pincer type FAI to those made in patients with pure cam-type to collect parameters that may be useful in the diagnosis and classification of pincer impingement.

Introduction: Surgical treatment of femoroacetabular impingement (FAI) is becoming a worldwide current practice. We analyse if clinical and functional results are influenced by preoperative degenerative hip changes. Materials and Methods: 107 FAI operated hips in 105 patients with a mean follow up of 3,1 years (range: 31 to 53 months) were evaluated and divided into 3 groups according to Tönnis Scala for preoperative radiological degenerative hip stages: group A 32 patients Tönnis 0, group B 61 Tönnis 1 and group C 24 Tönnis 2. Impingement test, Merle D’aubigné and WOMAC scores were assessed 6 weeks, 3 months, 6 months and every year after operation. SPSS 10.0 software used (SPSS INC, Chicago, Ill) was used for statistical analysis and comparisons were performed by means of chi-squared test; p< 0,05 was considered to be significant. Results: After 3 months impingement test improved significantly in 30 cases Tönnis 0 (93,75%; p=0,012) and 58 cases Tönnis 1 (95,08%; p=0,008), whereas in Tönnis 2 it was observed only in 14 cases (58,3%; p=0,354). At this point no statistical difference was observed at the subsequent three years (p=0,273, p=0,377, p=0,334). Merle D’Aubigné and WOMAC scores improved significantly at the latest follow-up in groups A (91,3%, p=0,010) and B (93,4,%, p=0,024). However in group C only 45,8% of the cases improved significantly (p=0,383). Conclusions: Surgical results of FAI differ in patients with Tönnis stage 0 and 1 when compared with Tönnis 2. Thus it seems to be reasonable to recommend symptomatic patients surgical treatment of FAI as early as it appears

Since its creation, labral repair has become the preferred method among surgeons for the arthroscopic treatment of acetabular labral tears resulting in pain and dysfunction for patients. Labral reconstruction is performed mainly in revision hip arthroscopy but can be used in the primary setting when the labrum cannot be repaired or is calcified. The purpose of this study was to compare the survival between primary labral repair and labral reconstruction with survival defined as no further surgery (revision or total hip replacement).

Patients who underwent labral repair or reconstruction between January 2005 and December 2018 in the primary setting were included in the study. Patients were included if they had primary hip arthroscopy with the senior author for femoroacetabular impingement (FAI), involving either labral reconstruction or labral repair, and were within the ages of 18 and 65 at the time of surgery. Exclusion criteria included confounding injuries (Leggs Calves Perthes, avascular necrosis, femoral head fracture, etc.), history of unilateral or bilateral hip surgeries, or Tönnis grades of 2 or 3 at the time of surgery. Labral repairs were performed when adequate tissue was available for repair and labral reconstruction was performed when tissue was absent, ossified or torn beyond repair.

A total of 501 labral repairs and 114 labral reconstructions performed in the primary setting were included in the study. Labral reconstruction patients were older (37±10) compared to labral repair (34±11).(p=0.021). Second surgeries were required in 19/114 (17%) of labral reconstruction and 40/501(8%) [odds ratio: 2.3; 95% CI 1.3 to 4.2] (p=0.008). Revision hip arthroscopy were required in 6/114(5%) labral reconstructions and 33/501(6.5%) labral repair (p=0.496). Total hip replacement was required in 13/114 labral reconstructions and 7/501 labral repairs [odds ratio:9.1 95%CI 3.5 to 23] (p=< 0.01). The mean survival for the labral repair group was 10.2 years (95%CI:10 to 10.5) and 11.9 years (98%CI:10.9 to 12.8) in the labral reconstruction group.

Conversion to total hip was required more often following primary labral reconstruction. Revision hip arthroscopy rates were similar between groups as was the mean survival, with both over 10 years. Similar survival was seen in labral repair and reconstruction when strict patient selection criteria are followed.

Dislocation is one of the most common complications in total hip arthroplasty (THA) and is primarily driven by bony or prosthetic impingement. The aim of this study was two-fold. First, to develop a simulation that incorporates the functional position of the femur and pelvis and instantaneously determines range of motion (ROM) limits. Second, to assess the number of patients for whom their functional bony alignment escalates impingement risk.

468 patients underwent a preoperative THA planning protocol that included functional x-rays and a lower limb CT scan. The CT scan was segmented and landmarked, and the x-rays were measured for pelvic tilt, femoral rotation, and preoperative leg length discrepancy (LLD). All patients received 3D templating with the same implant combination (Depuy; Corail/Pinnacle). Implants were positioned according to standardised criteria.

Each patient was simulated in a novel ROM simulation that instantaneously calculates bony and prosthetic impingement limits in functional movements. Simulated motions included flexion and standing-external rotation (ER). Each patient's ROM was simulated with their bones oriented in both functional and neutral positions.

13% patients suffered a ROM impingement for functional but not neutral extension-ER. As a result, 48% patients who failed the functional-ER simulation would not be detected without consideration of the functional bony alignment. 16% patients suffered a ROM impingement for functional but not neutral flexion. As a result, 65% patients who failed the flexion simulation would not be detected without consideration of the functional bony alignment.

We have developed a ROM simulation for use with preoperative planning for THA surgery that can solve bony and prosthetic impingement limits instantaneously. The advantage of our ROM simulation over previous simulations is instantaneous impingement detection, not requiring implant geometries to be analysed prior to use, and addressing the functional position of both the femur and pelvis.

Introduction: Femoroacetabular impingement (FAI) has been recently recognized as the main cause of hip pain in sportsmen. We analyse if clinical and functional results of surgical treatment are influenced by preoperative degenerative hip changes. Materials and Methods: A series of 117 consecutive Ribas mini open procedures (mini open femoroacetabular osteoplasty with labral refixation) were performed in 115 sportsmen with confirmed clinical, radiographic, and MR-arthrography diagnosis of FAI, and were evaluated with a minimum follow up of 4 years (range: 4 – 6,5). According to Tönnis Grade for preoperative radiological degenerative hip stage, the hips were divided into 3 groups: group A/Tönnis 0: 32 hips; group B/Tönnis 1: 61 hips; group C/Tönnis 2: 24 hips. A Combined Clinical Score (CCS), which includes Impingement test, Merle D’Aubigné and WOMAC scores, was used to evaluate the patients before surgery and at 6 weeks, 3 months, 6 months and every year after operation. Satisfactory and unsatisfactory results were obtained and collected. SPSS 10.0 software (SPSS INC, Chicago, Ill) was used for statistical analysis and comparisons were performed by means of chi-squared and Wilcoxon tests; p< 0,05 was considered to be significant. Results: With CCS method, satisfactory results were obtained in group A (Tönnis 0) in 93,4% of the cases at 12 months, in 96,5% at 24 months, and in 97,8% at the latest follow up of 48 months; in group B (Tönnis 1) satisfactory results were observed in 91,3% of the cases at 12 months, in 91,2% at 24 months, and in 93,6% at 48 months; in group C (Tönnis 2) satisfactory results were obtained in 58,3% of the cases at 12 months, in 55,3% at 24 months, and in 50,1% at 48 months. Differences between groups A and C, as like between groups B and C, were significant (p< 0,001), but not between groups A and B (p> 0,05). Conclusions: Midterm results of the Ribas mini open procedure for the treatment of femoroacetabular impingement are encouraging, expecially in hips not exceeding Tönnis Grade 1 osteoarthrosis, as results depend directly on degenerative state. If symptomatic patients are treated in early stages, excellent expectancies can be obtained with this procedure already at midterm. In addition, instruction of general physicians and specialists in the diagnosis of FAI is of paramount importance

Introduction: Femoroacetabular Impingement had been until now an unknown pathology. It causes pain in the movements of flexion-adduction-internal rotation, due to a bump effect between the head-neck surface of the femur and the anterior acetabular rim. Material and Method: We analysed our 14 first patients, 3 operated bilaterally with 1 year F.U.. In bilateral cases, the time between both operations ranged from 5 to 8 weeks. Mean Age: 36 years (27 to 48), all sports active patients.. The technique that we used was through our modified Hueter approach . The superoanterior rim of the acetabulum was excised as well as the deformity at the femoral side that causes a less femoral neck-offset. For that purpose we used special maxilofacial-reamers instead of chisels. In this way we avoid any bleeding from the femoral neck. With this technique we avoid a Trochanter osteotomy, as performed by other authors (Ganz, Trousdale) . Results: Pain relief was obtained 4 weeks after surgery in 13 from 14 patients. Mean hospitalization time was 2,6 days (2 to 5). Improvement in ROM was significative (p= 0,006): from −17 mean internal rotation (−14 to −28) at 80 flexion to +23 mean one month postop internal rotation (14 to 32).There was a significant improvement of hip score according to Merle d’Aubigne evaluation (p=0,017): 13,8 points preop (13 to 15) to 16,9 at F.U. (16–18). Neither Trendelemburg nor osteonecrosis was observed in any patient, as possible complications related to the approach. Mean time of rehabilitation was 3,8 weeks ( 3 to 5). All patients returned to their respective sports activities. Discussion: The Modified Femoroacetabular Osteoplasty allows rapid improvement of the normal hip motion , relatively short rehabilitation time and sports resumption as well. However midterm new osteoarthritic changes had to be assessed, although clinical and functional improvement has been evident. This surgical procedure makes us think about other alternatives to hip endoprosthesis in young adults

This study used a national registry to assess the outcomes of hip arthroscopy (HA) for the treatment femoroacetabular impingement (FAI).

All HAs for FAI recorded in the UK Non-Arthroplasty Hip Registry (NAHR) between January 2012 and September 2023 were identified. Cases were grouped according to the index procedure performed for FAI (cam, pincer, or mixed). Patient outcomes captured included the International Hip Outcome Tool (iHOT)-12.

7,511 HAs were identified; 4,583 cam (61%), 675 pincer (9%), 2,253 mixed (30%). Mean age (34.8) was similar between groups. There was a greater proportion of females in the pincer group (75%) compared to cam (52%) and mixed (50%). A higher proportion of patients had a recorded cartilage injury in association with a cam lesion compared to pincer. The pincer group had poorer mean pre-op iHOT-12 scores (31.6 \[95%CI 29.9 to 33.3\]; n=364) compared to cam (33.7 \[95%CI 32.1 to 34.4\]; n=3,941) and achieved significantly lower scores at 12 months (pincer = 52.6 (50.2 to 55); n=249, cam = 58.3 (57.1 to 59.5); n=1,679).

Overall, significant (p < 0.0001) iHOT-12 and EQ-5D improvement vs baseline pre-operative scores were achieved for all FAI subtypes at 6 months (overall mean iHOT-12 improvement +26.0 \[95%CI 25.0 to 26.9\]; n=2,983) and maintained out to 12 months (+26.2 \[25.1 to 27.2\]; n=2,760) at which point 67% and 48% of patients continued to demonstrate a score improvement greater than or equal to the minimum clinically important difference (>/=13 points) and substantial clinical benefit (>/=28 points) for iHOT-12 respectively.

This study demonstrates excellent early functional outcomes following HA undertaken for FAI in a large national registry.

Femoroacetabular impingement is a prearthritic deformity frequently associated with early chondral damage. Several techniques exist for restoring larger cartilage defects. While AMIC proved to be an effective treatment in knee and ankle, there are only short-term data available in hip. This study aimed to investigate the mid-term clinical outcome of patients with chondral lesions treated by AMIC and evaluate the quality of repair tissue via MRI.

This retrospective, single center study includes 18 patients undergoing surgical hip dislocation for FAI between 2013 and 2016. Inclusion criteria were: cam or pincer-type FAI, femoral or acetabular chondral lesions > 1 cm², (IRCS III-IV). Due to exclusion criteria and loss-to-follow-up 9 patients (10 hips) could be included. Patient reported outcome measures included Oxford Hip Score (OHS) & Core Outcome Measure Index (COMI)). MRIs were evaluated using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score.

None of the patients underwent revision surgery except screw removals from the greater trochanter. Followup data indicate a satisfactory to good hip function at 5 years: PROMS improved from pre- to postop at 5 years: OHS from 38.1 to 43.4, COMI from to 1.8 and UCLA from 4 to 8.1 respectively. MOCART score was 67.5 postoperatively. Subgrouping showed slightly better results for acetabular defects (Ø 69.4) compared femoral defects (Ø 60).

Based on the reported mid-term results, we consider AMIC as a valuable treatment option for larger chondral defects of the hip.

Femoroacetabular impingement (FAI) results from a morphological deformity of the hip and is associated with osteoarthritis (OA). Increased bone mineral density (BMD) is observed in the antero-superior acetabulum rim where impingement occurs. It is hypothesized that the repeated abnormal contact leads to damage of the cartilage layer, but could also cause a bone remodelling response according to Wolff's Law. Thus the goal of this study was to assess the relationship between bone metabolic activity measured by PET and BMD measured in CT scans.

Five participants with asymptomatic cam deformity, three patients with uni-lateral symptomatic cam FAI and three healthy controls were scanned in a 3T PET-MRI scanner following injection with [18F]NaF. Bone remodelling activity was quantified with Standard Uptake Values (SUVs). SUVmax was analyzed in the antero-superior acetabular rim, femoral head and head-neck junction. In these same regions, BMD was calculated from CT scans using the calibration phantom included in the scan. The relationship between SUVmax and BMD from corresponding regions was assessed using the coefficient of determination (R²) from linear regression.

High bone activity was seen in the cam deformity and acetabular rim. SUVmax was negatively correlated with BMD in the antero-superior region of the acetabulum (R²=0.30, p=0.08). SUVmax was positively correlated with BMD in the antero-superior head-neck junction of the femur (R²=0.359, p=0.067). Correlations were weak in other regions.

Elevated bone turnover was seen in patients with a cam deformity but the relationship to BMD was moderate. This study demonstrates a pathomechanism of hip degeneration associated with FAI deformities, consistent with Wolff's law and the proposed mechanical cause of hip degeneration in FAI. [18F]-NaF PET SUV may be a biomarker of degeneration, especially in early stages of degeneration, when joint preservation surgery is likely to be the most successful.

Femoroacetabular impingement (FAI) is a common cause of hip pain in the young adult. Uncertainty regarding surgical indications, outcome assessment, management preferences and perceptions of the literature exist. We conducted a large international survey assessing the perceptions and demographics of orthopaedic surgeons regarding FAI.

A survey was developed using previous literature, focus groups and a sample-to-redundancy strategy. The survey contained forty-six questions and was emailed to national orthopaedic associations and orthopaedic sports medicine societies for member responses. Members were contacted on multiple occasions to increase response rates.

Nine hundred orthopaedic surgeons from twenty national and international organisations completed the survey. Surgeons responded across 6 continents, 58.2 % from developed nations with 35.4 % having sports fellowship training. North American and European surgeons reported significantly greater exposure to hip arthroscopy during residency and fellowships in comparison to international respondents (48.0% vs. 44.5% vs. 25.6% respectively; p<0.001). Surgeons performing a higher volume of FAI surgery (over 100 cases per year) were significantly more likely to have practiced for more than 20 years (OR 1.91; 95% CI 1.01 to 3.63), be practicing at an academic hospital (OR 2.25; 95% CI 1.22 to 4.15), and have formal arthroscopy training (OR 46.17; 95% CI 20.28 to 105.15). High volume surgeons were over two-fold more likely to practice in North America and Europe (OR 2.26; 95% CI: 1.08 to 4.72).

The exponential rise in the diagnosis and surgical management for FAI appears to be driven largely by experienced surgeons in developed nations. Our analysis suggests that although FAI management is early in the innovation cycle we are at a tipping point towards wider uptake and utilisation. The results of this survey will help guide further research and study.

To evaluate the impact of routine capsular repair on patient-reported outcomes, survivorship and achievability of clinically important improvement, minimum 5-years post-surgery.

Our prospective institutional registry was reviewed for cases undergoing primary HA for FAI, and stratified into two groups depending on whether the capsule was repaired or not. Routine repair was introduced in late 2013. The No Repair group consisted of patients undergoing HA between Jan 2010-June 2013 while the Repair group consisted of patients undergoing HA between Jan 2015-Sept 2018. Exclusion criteria consisted of >50 years, Tonnis>1, dysplasia(LCEA<25), concomitant hip pathologies. PROMs consisted of mHHS, SF36 and UCLA. Metrics of clinically important improvement was evaluated using MCID and SCB. Rates of repeat HA or THA conversion were recorded.

985 cases were included (359 No Repair; 626 Repair), 86% male, average age 27.4±6.7years. Significant improvement in all PROMs at minimum 5-years was observed for both groups (p<0.001 for all; large effect sizes for mHHS and SF36, medium effect sizes for UCLA). At 5-years post-op there was no significant difference between groups for mHHS(p=0.078) or UCLA(0.794). SF36 was significantly poorer for those cases undergoing routine repair(p<0.001) however effect size was small (0.20). Thresholds of MCID and SCB were calculated as 69% and 86% for mHHS, 64% and 77% for UCLA, 43% and 60% for SF36. Both groups achieved MCID and SCB at similar rates for mHHS and UCLA. A significantly lower proportion of cases in the repair groups achieved MCID for SF36 (53.6% vs 63.5%, p=0.034) and SCB for SF36 (37.3% vs 52.8%, p<0.001). No significant difference between groups for THA conversion (0.6% No Repair vs 0.5% Repair) or repeat HA (9.7% No Repair vs 8.1% Repair).

Routinely repairing the capsule following HA for FAI demonstrates no clinical benefit over not repairing the capsule 5 years post-surgery

Interstitial supraspinatus tears can cause persistent subacromial impingement symptoms despite non operative treatment. Autologous tendon cell injection (ATI) is a non-surgical treatment for tendinopathies and tear. We report a randomised controlled study of ATI compared to corticosteroid injection (CS) as treatment for interstitial supraspinatus tears and tendinopathy.

Inclusion criteria were patients with symptom duration > 6 months, MRI confirmed intrasubstance supraspinatus tear, and prior treatment with physiotherapy and ≥ one CS or PRP injection. Participants were randomised to receive ATI to the interstitial tear or corticosteroid injection to the subacromial bursa in a 2:1 ratio, under ultrasound guidance. Assessments of pain (VAS) and function (ASES) were performed at baseline, and 1, 3, 6 and 12 months post treatment.

30 participants (19 randomised to ATI) with a mean age of 50.5 years (10 females) and a mean duration of symptoms of 23.5 months. Baseline VAS pain and ASES scores were comparable between groups. While mean VAS pain scores improved in both groups at 3 months after treatment, pain scores were superior with ATI at 6 months (p=0.01). Mean ASES scores in the ATI group were superior to the CS group at 3 months (p=0.026) and 6 months (p=0.012). Seven participants in the CS group withdrew prior to 12 months due to lack of improvement. At 12 months, mean VAS pain in the ATI group was 1.6 ± 1.3. The improvements in mean ASES scores in the ATI group at 6 and 12 months were greater than the MCID (12.0 points). At 12 months, 95% of ATI participants had an ASES score > the PASS (patient acceptable symptom state).

This is the first level one study using ATI to treat interstitial supraspinatus tear. ATI results in a significant reduction in pain and improvement in shoulder function.

Introduction and Objective

To estimate the prevalence of acetabular ossifications in the adult population with asymptomatic, morphologically normal hips at CT and to determine whether the presence of labral ossifications is associated with patient-related (sex, age, BMI), or hip-related parameters (joint space width, and cam- and pincer-type femoroacetabular impingement morphotype).

The postoperative pain after hip arthroscopy remains a major challenge in the immediate postoperative period. Adequate postoperative analgesia has been associated with increased patient satisfaction and decreased consumption of opioids. We evaluated the efficacy of pericapsular nerve group block (PENG) versus fascia iliaca block (FIB) in reducing post-operative pain and analgesic consumption within the first 24 hours following arthroscopic management of femoroacetabular impingement (FAI).

Thirty-nine patients (17 females and 25 males, ages 18–42 years, mean ± SD (27.9 ± 6.2), and mean BMI of 25.13±5.08 kg/m2 were scheduled for primary arthroscopic management of FAI. Included patients were randomized into two groups according to the block used in each. Group (A) 19 patients were included and had FIB and group (B) 20 patients were included and received PENG block. The efficacy of both techniques was clinically and statistically valuated using VAS score and quadriceps muscle power.

There was a statically significance difference in the mean at rest between the two groups at all measured time points following surgery (6, 12, 18 and 24 h). Also, in dynamic pain scores (with hip flexion) scores were statistically significant at 24 hours post-operative (P = .001). Total opioid consumption in the first 24 hours postoperative was lower in the PENG group with significant difference of mean 16.5 ±9.9 mg for PENG group versus 27.5±9.6 mg for FIB group (P < .005). Five patients (26.31%) in FIB group had weaker quadriceps muscle power while none in PENG group patients had quadriceps weakness.

PENG block might be considered as an ideal regional anesthesia modality for hip arthroscopy. As an alternative to more conventional regional nerve blocks such as a fascia iliaca block. PENG block is easily performed in the preoperative setting, and appears to spare motor function while providing a prolonged sensory pain relief.

Abstract

Optimal acetabular component position in Total Hip Arthroplasty is vital for avoiding complications such as dislocation and impingement, Transverse acetabular ligament (TAL) have been shown to be a reliable landmark to guide optimum acetabular cup position. Reports of iliopsoas impingement caused by acetabular components exist. The Psoas fossa (PF) is not a well-regarded landmark for Component positioning. Our aim was to assess the relationship of the TAL and PF in relation to Acetabular Component positioning.

A total of 22 cadavers were implanted on 4 occasions with the an uncemented acetabular component. Measurements were taken between the inner edge of TAL and the base of the acetabular component and the distance between the lower end of the PF and the most medial end of TAL.

The distance between the edge of the acetabular component and TAL was a mean of 1.6cm (range 1.4–18cm). The distance between the medial end of TAL and the lowest part of PF was a mean of 1.cm (range 1,3–1.8cm) It was evident that the edge of PF was not aligned with TAL.

Optimal acetabular component position is vital to the longevity and outcome following THA. TAL provides a landmark to guide acetabular component position. However we feel the PF is a better landmark to allow appropriate positioning of the acetabular component inside edge of the acetabulum inside the bone without exposure of the component rim and thus preventing iliopsoas impingement at the psoas notch and resultant groin pain.

Arthroscopic management of femoroacetabular impingement (FAI) has become the mainstay of treatment. However, chondral lesions are frequently encountered and have become a determinant of less favourable outcomes following arthroscopic intervention.

The aim of this systematic review and meta-analysis was to assess the outcomes of hip arthroscopy (HA) in patients with FAI and concomitant chondral lesions classified as per Outerbridge.

A systematic search was performed using the PRISMA guidelines on four databases including MEDLINE, EMBASE, Cochrane Library and Web of Science. Studies which included HA as the primary intervention for management of FAI and classified chondral lesions according to the Outerbridge classification were included. Patients treated with open procedures, for osteonecrosis, Legg-Calve-Perthes disease, and previous ipsilateral hip fractures were excluded. From a total of 863 articles, twenty-four were included for final analysis. Demographic data, PROMs, and radiological outcomes and rates of conversion to total hip arthroplasty (THA) were collected. Risk of bias was assessed using ROBINS-I.

Improved post-operative PROMs included mHHS (mean difference:-2.42; 95%CI:-2.99 to −1.85; p<0.001), NAHS (mean difference:-1.73; 95%CI: −2.23 to −1.23; p<0.001), VAS (mean difference: 2.03; 95%CI: 0.93-3.13; p<0.001). Pooled rate of revision surgery was 10% (95%CI: 7%-14%). Most of this included conversion to THA, with a 7% pooled rate (95%CI: 4%-11%).

Patients had worse PROMs if they underwent HA with labral debridement (p=0.015), had Outerbridge 3 and 4 lesions (p=0.012), concomitant lesions of the femoral head and acetabulum lesions (p=0.029). Reconstructive cartilage techniques were superior to microfracture (p=0.042). Even in concomitant lesions of the femoral head and acetabulum, employing either microfracture or cartilage repair/reconstruction provided a benefit in PROMs (p=0.027).

Acceptable post-operative outcomes following HA with labral repair/reconstruction and cartilage repair in patients with FAI and concomitant moderate-to-severe chondral lesions, can be achieved. Patients suffering from Outerbridge 3 and 4 lesions, concomitant acetabular rim and femoral head chondral lesions that underwent HA with labral debridement, had worse PROMs. Reconstructive cartilage techniques were superior to microfracture. Even in concomitant acetabular and femoral head chondral lesions, employing either microfracture or cartilage repair/reconstruction was deemed to provide a benefit in PROMs.

Abstract

Purpose The aim of this study was investigate the relationship between version and torsional abnormalities of the acetabulum, femur and tibia in patients with symptomatic FAI. Methods A systematic review was performed according to PRISMA guidelines using the EMBASE, MEDLINE, PubMed and Cochrane databases. Original research articles evaluating the described version and torsional parameters in FAI were included. The MINORS criteria was used to appraise study quality and risk of bias. Mean version and torsion values were displayed using forest plot and the estimated proportion of hips displaying abnormalities in version/torsion were calculated.

Identification of patients at risk of not achieving minimally clinically important differences (MCID) in patient reported outcome measures (PROMs) is important to ensure principled and informed pre-operative decision making. Machine learning techniques may enable the generation of a predictive model for attainment of MCID in hip arthroscopy.

Aims: 1) to determine whether machine learning techniques could predict which patients will achieve MCID in the iHOT-12 PROM 6 months after arthroscopic management of femoroacetabular impingement (FAI), 2) to determine which factors contribute to their predictive power.

Data from the UK Non-Arthroplasty Hip Registry database was utilised. We identified 1917 patients who had undergone hip arthroscopy for FAI with both baseline and 6 month follow up iHOT-12 and baseline EQ-5D scores. We trained three established machine learning algorithms on our dataset to predict an outcome of iHOT-12 MCID improvement at 6 months given baseline characteristics including demographic factors, disease characteristics and PROMs. Performance was assessed using area under the receiver operating characteristic (AUROC) statistics with 5-fold cross validation.

The three machine learning algorithms showed quite different performance. The linear logistic regression model achieved AUROC = 0.59, the deep neural network achieved AUROC = 0.82, while a random forest model had the best predictive performance with AUROC 0.87. Of demographic factors, we found that BMI and age were key predictors for this model. We also found that removing all features except baseline responses to the iHOT-12 questionnaire had little effect on performance for the random forest model (AUROC = 0.85). Disease characteristics had little effect on model performance.

Machine learning models are able to predict with good accuracy 6-month post-operative MCID attainment in patients undergoing arthroscopic management for FAI. Baseline scores from the iHOT-12 questionnaire are sufficient to predict with good accuracy whether a patient is likely to reach MCID in post-operative PROMs.

Abstract

To determine the effect that preoperative use of 3D printed models has on the outcomes for femoroacetabular impingement (FAI) surgery.

Ninety patients that underwent FAI surgeries by the same surgeon were retrospectively analyzed. Patients were age- and sex-matched for two groups - those who had pre-operative 3D printed hip models (n=45) and those with conventional planning using X-rays and/or CT scan (n=45) were identified. Radiographic parameters on pre- and post-operative radiographs that include the alpha angle (45 Dunn view), center edge angle (CEA) (weight bearing AP pelvis), and head-neck offset ratio (cross-table lateral) were obtained. Clinical outcomes were assessed by analyzing iHOT and HOS scores pre- and post-operatively.

Ninety patients (3D printed group 45, Conventional group 45) with a mean age of 36 years were evaluated. Mean follow-up time was 28 months. For all of the radiological variables (CEA and alpha angle), there was a significant improvement seen for both groups (p=0.001). However, the 3D printed group showed significantly better resection of bone to a normal alpha angle (< 5 5) than did the Conventional group. Additionally, head-neck offset was significantly better in the 3D printed group (p=0.001). Statistically significant improvements were seen in both groups on the HOS and iHOT-33 (p=0.001).

Planning FAI surgery using 3D hip models helps in achieving better resection, especially in CAM-type FAI.

Periacetabular osteotomy (PAO) is an established treatment for developmental hip dysplasia (DDH) in young adults and can also be utilised in the management of femoroacetabular impingement (FAI) with acetabular retroversion. This study used a national registry to assess the outcomes of PAO for DDH and FAI.

PAOs recorded in the UK Non-Arthroplasty Hip Registry between 2012 and November 2022 were identified along with recorded patient and surgical characteristics. Cases were grouped according to the primary pathology (DDH or FAI). Patient reported outcome measures (PROMs) captured included the International Hip Outcome Tool (iHOT)-12 (primary outcome) and the EuroQol-5 Dimensions (EQ-5D) index preoperatively and at 6 months, 1, 2, and 5 years post-operatively.

1,087 PAOs were identified; 995 for DDH (91%), 98 for FAI (9%). Most patients (91%) were female. The DDH group were significantly older (mean 31.7 years) than the FAI group (25.4 years) but had similar body mass index (mean 25.7kg/m2). Overall, significant (all p<0.0001) iHOT-12 and EQ-5D improvement (delta) vs baseline pre-operative scores were achieved at 6 months (mean iHOT-12 improvement +27.4 (95%CI 25.3 to 29.5); n=515) and maintained out to 5 years (+30.0 (21.4 to 38.6); n=44 [9.8% of those eligible for follow-up at 5 years]), at which point 71% and 55% of patients continued to demonstrate a score improvement greater than or equal to the minimum clinically important difference (≥13 points) and substantial clinical benefit (≥28 points) for iHOT-12 respectively.

This study demonstrates excellent functional outcomes following PAO undertaken for DDH and FAI in the short to medium term in a large national registry.

Abstract

INTRODUCTION

Component impingement in total hip arthroplasty (THA) can cause implant damage or dislocation. Dual mobility (DM) implants are thought to reduce dislocation risk, but impingement on metal acetabular bearings may cause femoral component notching. We studied the prevalence of (and risk factors for) femoral notching with DM across two institutions.

The purpose of this study was to compare the outcomes of arthroscopic unilateral surgery and simultaneous bilateral surgery for posterior ankle impingement syndrome (PAIS) in athletes and to evaluate the usefulness of simultaneous bilateral surgery.

A total 48 hindfeet of 41 athletes (14 hindfeet of 14 males, 34 hindfeet of 27 females) who underwent arthroscopic surgery for PAIS were studied. Japanese society for surgery of the foot (JSSF) score and visual analogue scale (VAS) were compared before and after surgery, using Wilcoxon signed-rank test. The operation time and the time to return to sports activity were compared in 10 hindfeet of 5 patients who underwent simultaneous bilateral surgery and 38 hindfeet of 36 patients who underwent unilateral surgery, using Wilcoxon rank sum test.

Classic ballet was the most common type of sport that caused PAIS (59%, 24/41 athletes). Soccer (10%, 4/41 athletes), baseball (10%, 4/41 athletes), badminton (5%, 2/41 athletes), volleyball (5%, 2/41 athletes), and athletics (5%, 2/41 athletes) followed. The JSSF score improved significantly from 72.7 preoperatively to 98.9 postoperatively in unilateral surgery, and significantly improved from 75.2 preoperatively to 99.0 postoperatively in simultaneous bilateral surgery. VAS significantly decreased from 64.7 preoperatively to 4.8 postoperatively in unilateral surgery, and significantly decreased from 72.7 preoperatively to 1.0 postoperatively in simultaneous bilateral surgery. The operating time was 53.7 minutes on average for unilateral surgery and 101.0 minutes for simultaneous bilateral surgery, significantly longer in bilateral simultaneous surgery. The mean time to return to sports activity was 4.8 weeks for unilateral surgery and 9.6 weeks for simultaneous bilateral surgery, significantly longer in simultaneous bilateral surgery.

Both unilateral and simultaneous bilateral surgeries for PAIS in athletes were useful. It should be noted that the operating time and the time to return to sports will be longer. However, considering the 2 times hospitalizations and 2 times surgeries, simultaneous bilateral surgery is one of the treatment options for PAIS.

Mechanical irritation or impingement of the iliopsoas tendon accounts for 2–6% of persistent postoperative pain cases after total hip arthroplasty (THA). The most common trigger is anterior cup overhang. CT-scan can be used to identify and measure this overhang; however, no threshold exists for symptomatic anterior iliopsoas impingement. We conducted a case–control study in which CT-scan was used to define a threshold that differentiates patients with iliopsoas impingement from asymptomatic patients after THA.

We analyzed the CT-scans of 622 patients (758 CT-scans) between 2011 and 2020. Out of this population we identified 136 patients with symptoms suggestive of iliopsoas impingement. Among them, 6 were subsequently excluded: three because the diagnosis was reestablished intra-operatively (one metallosis, two anterior instability related to posterior prosthetic impingement) and three because they had another obvious cause of impingement (one protruding screw, one protruding cement plug, one stem collar), leaving 130 patients in the study (impingement) group. They were matched to a control group of 138 patients who were asymptomatic after THA. The anterior cup overhang (anterior margin of cup not covered by anterior wall) was measured by an observer (without knowledge of the clinical status) on an axial CT slice based on anatomical landmarks (orthogonal to pelvic axis).

The impingement group had a median overhang of 8 mm [IQR: 5 to 11] versus 0 mm [IQR: 0 to 4] for the control group (p<.001). Using ROC curves, an overhang threshold of 4 mm was best correlated with a diagnosis of impingement (sensitivity 79%, specificity 85%, PPV = 75%, NPV = 85%).

Pain after THA related to iliopsoas 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 iliopsoas irritation or another reason for the pain after THA before concluding impingement is present.

FAI may cause pain or functional impairment for an individual, as well as potentially resulting in arthritis and degeneration of the hip joint. Results from recent randomised control trials demonstrate the superiority of surgery over physiotherapy in patients with FAI. However, there is paucity of evidence regarding which factors influence outcomes for FAI surgery, most notably on patient reported outcomes measures (PROMs).

Our study looks to explore factors influencing the outcomes for patients undergoing surgery for FAI utilising data from the Non-Arthroplasty Hip Registry.

This study is a retrospective analysis of data collected prospectively via the NAHR database. Patients meeting the inclusion criteria, who underwent surgery between January 2011 and September 2019 were identified and included in the study. Follow-up data was captured in September 2020 to allow a minimum of 12 months follow-up.

Patients consenting to data collection received questionnaires to determine EQ-5D Index and iHOT-12 scores preoperatively and at 6 months, 1, 2- and 5-year follow-up.

Changes in outcome scores were analysed for all patients and sub-analysis was performed looking at the influence of; FAI morphological subtype, age, and sex, on outcome scores.

Our cohort included 4,963 patients who underwent arthroscopic treatment for FAI. There was significant improvement from pre-operative PROMs when compared with those at 6 and 12 months.

Pre-operatively, and at 12-month follow-up, iHOT-12 scores were significantly better for the cam / mixed groups compared to the pincer group (p<0.01).

In multivariable regression analysis, pincer pathology and a high-grade chondral lesion were associated significantly poorer iHOT-12 improvement at 6 and 12 months (p<0.05)

Age (<40 vs >40) demonstrated no statistical significance when considering 12 months outcome scores.

This study demonstrates that hip arthroscopy is an effective treatment for patients with symptomatic FAI and shows statistically significant improvements at 12 months.

The findings of this study are relevant to orthopaedic surgeons who manage young adults with hip pathology. This will help them to; predict which patients may benefit from operative intervention, and better inform patients, when undertaking shared decision making.

Introduction

The prevalence of the various patterns of spinopelvic abnormalities that increase the risk for prosthetic impingement is unknown. While prior surgery or lumbar fusion are recognized as a risk factors for postoperative dislocation, many patients presenting for THA do not have obvious radiographic abnormalities. The purpose of this study is to determine the prevalence of large posterior pelvic tilt (PPT) when standing, stiff lumbar-spine (SLL) and spino-pelvic sagittal imbalance (SSI) in patients undergoing primary THA.

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.

Iliopsoas tendonitis after total hip arthroplasty (THA) can be a considerable cause of pain and patient dissatisfaction. The optimal cup position to avoid iliopsoas tendonitis has not been clearly established. Implant designs have also been developed with an anterior recess to avoid iliopsoas impingement. The purpose of this cadaveric study was to determine the effect of cup position and implant design on iliopsoas impingement.

Bilateral THA was performed on three fresh frozen cadavers using oversized (jumbo) offset head center revision acetabular cups with an anterior recess (60, 62 and 66 mm diameter) and tapered wedge primary stems through a posterior approach. A 2mm diameter flexible stainless steel cable was inserted into the psoas tendon sheath between the muscle and the surrounding membrane to identify the location of the psoas muscle radiographically. CT scans of each cadaver were imported in an imaging software. The acetabular shells, cables as well as pelvis were segmented to create separate solid models of each. The offset head center shell was virtually replaced with an equivalent diameter hemispherical shell by overlaying the outer shell surfaces of both designs and keeping the faces of shells parallel. The shortest distance between each shell and cable was measured. To determine the influence of cup inclination and anteversion on psoas impingement, we virtually varied the inclination (30°/40°/50°) and anteversion (10°/20°/30°) angles for both shell designs.

The CT analysis revealed that the original orientation (inclination/anteversion) of the shells implanted in 3 cadavers were as follows: Left1: 44.7°/23.3°, Right1: 41.7°/33.8°, Left2: 40/17, Right2: 31.7/23.5, Left3: 33/2908, Right3: 46.7/6.3. For the offset center shells, the shell to cable distance in all the above cases were positive indicating that there was clearance between the shells and psoas. For the hemispherical shells, in 3 out of 6 cases, the distance was negative indicating impingement of psoas. With the virtual implantation of both shell designs at orientations 40°/10°, 40°/20°, 40°/30° we found that greater anteversion helped decrease psoas impingement in both shell designs. When we analyzed the influence of inclination angle on psoas impingement by comparing wire distances for three orientations (30°/20°, 40°/20°, 50°/20°), we found that the effect was less pronounced. Further analysis comparing the offset head center shell to the conventional hemispherical shell revealed that the offset design was favored (greater clearance between the shell and the wire) in 17 out of 18 cases when the effect of anteversion was considered and in 15 out of 18 cases when the effect of inclinations was considered.

Our results indicate that psoas impingement is related to both cup position and implant geometry. For an oversized jumbo cup, psoas impingement is reduced by greater anteversion while cup inclination has little effect. An offset head center cup with an anterior recess was effective in reducing psoas impingement in comparison to a conventional hemispherical geometry. In conclusion, adequate anteversion is important to avoid psoas impingement with jumbo acetabular shells and an implant with an anterior recess may further mitigate the risk of psoas impingement.

Surgical treatment options for Femoroacetabular impingement (FAI) includes both surgical dislocation and hip arthroscopy techniques. The primary aim of this study was to evaluate and compare the survivorship of arthroscopies (scope) and surgical dislocations (SD) at minimum 5-year follow-up. The secondary aim was to describe differences in functional outcomes between the 2 groups.

This was a retrospective, single surgeon, consecutive, case-series from a large tertiary care centre. We evaluated all surgeries that were performed between 2005 and 2011. Our institutional database was queried for any patient undergoing surgery for FAI (pincer (n=23), cam (n=306), or mixed (n=103) types). Patients with childhood pathologies i.e. Legg Calve Perthes and slipped capital femoral epiphysis were excluded. This resulted in 221 hips (169 males, 52 females) who underwent either SD (94, 42.5%) or scope (127, 57.5%). A manual chart review was completed to identify patients who sustained a complication, underwent revision surgery or progressed to a total hip arthroplasty (THA). In addition, we reviewed prospectively collected patient reported outcome measure (PROMs) using (SF12, HOOS, and UCLA). Survivorship outcome was described for the whole cohort and compared between the 2 surgical groups. PROMs between groups were compared using The Mann-Whitney U test and the survival between groups was assessed using the Kaplan-Meier Analysis and the Log-Rank Mantel Cox test. All analyses were performed in SPSS (IBM, v. 26.0).

The cohort included 110 SDs and 320 arthroscopies. The mean age of the whole cohort was 34±10; patients in the SD group (32±9) were younger compared to the arthroscopy group (39±10) (p<0.0001). There were 16 post-operative complications (similar between groups) and 77 re-operations (more common in the SD group (n=49) due to symptomatic metal work (n=34)). The overall 10-year survival was 91±3%. Survivorship was superior in the arthroscopy group at both 5- (96% (95%CI: 93 – 100)) and 8- years 94% (95%CI: 90 – 99%) compared to the SD Group (5-yr: 90% (95%CI: 83 – 98); 8-yr: 84% (95%CI:75 – 93)) (p=0.003) (Figure 1). On average HOOS improved from 54±19 to 68±22 and WOMAC from 65±22 to 75±22. The improvement in PROMs were similar between the 2 groups.

We report very good long-term joint preservation for the treatment of FAI, which is similar to those reported in hip dysplasia. In addition, we report satisfactory improvement in function following such treatment. The differences reported in joint survival likely reflect selection biases from the treating surgeon; more complex cases and those associated with more complex anatomy were more likely to have been offered a SD in order to address the pathology with greater ease and hence the inferior joint preservation identified in this group.

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Long femoral nails for neck of femur fractures and prophylactic fixation have a risk of anterior cortex perforation. Previous studies have demonstrated the radius of curvature (ROC) of a femoral nail influencing the finishing point of a nail and the risk of anterior cortex perforation. This study aims to calculate a patients femoral ROC using preoperative XR and CT and therefore nail finishing position.

We conducted a retrospective study review of patients with long femoral cephalomedullary nailing for proximal femur fractures (OTA/AO 31(A) and OTA/AO 32) or impending pathological fractures at a level 1 trauma centre between January 1, 2015 and December 31, 2020 with both full length lateral X-ray and CT imaging. Femoral ROC was calculated on both imaging modalities. Outcomes measured including nail finishing position, anterior cortex encroachment and impingement. The mean femoral ROC was 1026mm on CT and 1244mm on XR. CT femoral ROC strongly correlated with nail finishing point with a spearmans coefficient of 0.77. Additionally, femurs with a ROC <1000mm were associated with a higher risk of anterior encroachment (OR 6.12) and femurs with a ROC <900mm were associated with a higher risk of anterior cortex impingement (OR 6.47).

To our knowledge this is the first study to compare a measured femoral ROC to nail finishing position. The use of CT to measure femoral ROC and to a lesser extent XR was able to predict both nail finishing position and risk of anterior cortex encroachment. Preoperative XRs and CTs were able to identify patients with a small femoral ROC. This predicted patients at risk of anterior cortex impingement, anterior cortex encroachment and nail finishing position. We may be able to select femoral nails that resemble the native femoral ROC and mitigate the risk of anterior cortex perforation.

The literature indicates that femoroacetabular impingement (FAI) patients do not return to the level of controls (CTRL) following surgery. The purpose of this study was to compare hip biomechanics during stair climbing tasks in FAI patients before and two years after undergoing corrective surgery against healthy controls (CTRL).

A total of 27 participants were included in this study. All participants underwent CT imaging at the local hospital, followed by three-dimensional motion analysis done at the human motion biomechanics laboratory at the local university. Participants who presented a cam deformity >50.5° in the oblique-axial or >60° in the radial planes, respectively, and who had a positive impingement test were placed in the FAI group (n=11, age=34.1±7.4 years, BMI=25.4±2.7 kg/m2). The remaining participants had no cam deformity and negative impingement test and were placed in the CTRL group (n=16, age=33.2±6.4 years, BMI=26.3±3.2 kg/m2). The CTRL group completed the biomechanics protocol once, whereas the FAI group completed the protocol twice, once prior to undergoing corrective surgery for the cam FAI, and the second time at approximately two years following surgery.

At the human motion biomechanics laboratory, participants were outfitted with 45 retroreflective markers placed according to the UOMAM marker set. Participants completed five trials of stairs task on a three step instrumented stair case to measure ground reaction forces while 10 Vicon MX-13 cameras recorded the marker trajectories. Data was processed using Nexus software and divided into stair ascent and stair descent tasks. The trials were imported into custom written MatLab software to extract peak pelvis and hip kinematics and hip kinetic variables. Non-parametric Kruskal-Wallis tests were used to determine significant (p < 0.05) differences between the groups.

No significant differences occurred during the stair descent task between any of the groups. During the stair ascent task, the CTRL group had significantly greater peak hip flexion angle (Pre-Op=58±7.1°, Post-Op=58.1±6.6°, CTRL=64.1±5.1°) and sagittal hip range of motion (ROM) (Pre-Op=56.7±6.7°, Post-Op=56.3±5.5°, CTRL=61.7±4.2°) than both the pre- and post-operative groups. Pre-operatively, the FAI group had significantly less peak hip adduction angle (Pre-Op=2±4.5°, Post-Op=3.4±4.4°, CTRL=5.5±3.7°) and hip frontal ROM (Pre-Op=9.9±3.4°, Post-Op=11.9±5.4°, CTRL=13.4±2.5°) compared to the CTRL group. No significant differences occurred in the kinetic variables.

Our findings are in line with the Rylander and colleagues (2013) who also found that hip sagittal ROM did not improve following corrective surgery. Their study included a mix of cam and pincer-type FAI, and had a mean follow-up of approximately one year. Our cohort included only cam FAI and they had a mean follow-up of approximately two years, indicating with the extra year, the patients still did not show sagittal hip kinematics improvement. In the frontal plane, there was no significant difference between the post-op and the CTRL, indicating that the postoperative FAI reached the level of the CTRLs. This is in line with recent work that indicates a more medialized hip contact force vector following surgery, suggesting better hip stabilization.

Shoulder impingement is one of the most common non-traumatic upper limb causes of disability in adults. Often resulting in pain and disability, management remains highly debated. This meta-analysis of randomized trials aims to evaluate the efficacy of surgical intervention in the setting of shoulder impingement in comparison to non-operative or sham treatments.

Two reviewers independently screened MEDLINE, EMBASE, PUBMED and Cochrane databases for randomized control trials published from 1946 through to May 19th, 2018. A risk of bias assessment was conducted for all included studies and outcomes were pooled using a random effects model. The primary outcome was improvement in pain up to two years. Secondary outcomes included functional outcome scores reported at the short term (/=2 years). Heterogeneity was assessed using the I2statistic. Functional outcome scores were presented along with minimal clinically important differences to provide clinical context to findings.

Twelve RCT's (n=1062 patients) were included in this review. Eligible patients were a mean age of 48 (SD +/− 4) years with 45% being male gender. The pooled treatment effect of surgical intervention for shoulder impingement did not demonstrate any benefit to surgery with respect to pain relief (mean difference [MD] −0.07, 95% CI −0.40 to 0.26) or short-term functional outcomes (standardized mean difference [SMD] −0.09, 95% confidence interval [CI] −0.27 to 0.08). Surgical intervention did result in a small statistically significant but clinically unimportant improvement in long term functional outcomes (SMD 0.23, 95% CI 0.06 to 0.41).

Evidence suggests surgical intervention has little, if any, benefit for impingement pathology in the middle-aged patient.

In the young and highly active population of military patients, femoroacetabular impingement can be a source of serious disability as well as a threat to their career. This morbidity can be treated with hip arthroscopy with debridement of cam lesion, and excision or repair of a corresponding labral tear. We report on the long term outcomes (>1 year) of 26 military cases who underwent hip arthroscopy for femoroacetabular impingement, in a single surgeon's series. Twenty two patients (four bilateral cases) underwent hip arthroscopy as a day case procedure during the period February 2013 to October 2014. Non-Arthritic Hip Scores (NAHS) were obtained from patients pre-operatively, at two months, four months and at least one year post-operatively. There was a significant improvement in NAHS at two months (75.6)(p<0.05), four months (85.1)(p<0.001) and one year (84.8)(p<0.001), compared to pre-operative NAHS (65.8). There was no significant change in NAHS beyond four months. Only three out of the 22 patients were medically discharged secondary to persistent hip symptoms. Hip arthroscopy for femoroacetabular impingement is an effective, viable procedure for military patients. Mobility, pain and function is significantly improved after surgery. This improvement is sustained in the long term up to and beyond one year.

Abstract

When patients present at an early age with osteoarthritis of the hip, there is usually an underlying predisposing cause. In men, a common cause is femoroacetabular impingement (FAI). This is evident as anterior neck osteophytes, with retroversion and varus alignment of the femoral head, most likely the result of subclinical slipped capital femoral epiphysis.

The resulting femoroacetabular cam impingement causes degenerative osteoarthritis (OA) of the hip, at an earlier age than primary OA. Patients present in their 40s and 50s with advanced arthritis, and are faced with the prospect of a total hip arthroplasty. Women may experience this as well, but may present with early hip arthritis as a result of subclinical dysplasia or pincer FAI more often than their male counterparts.

Hip resurfacing has several advantages over traditional total hip replacement for younger patients, especially men. These include bone preservation, less dislocation, thigh pain or leg length inequality, easier return to athletics, and easy revision on the femoral side. It is indicated in young, active patients.

The resurfacing procedure realigns the femoral head on the native and resurfaces the arthritic joint. Anterior neck osteoplasty is performed. Head retroversion is corrected. This restores deep flexion, and eliminates forced external rotation in flexion. Hip resurfacing can be done through either an anterior or posterior approach, although the anterior approach gives easier access to the anterior femoral neck, and preserves the blood supply to the head. This may help prevent femoral neck fractures and late head collapse.

Background

Slipped capital femoral epiphysis (SCFE) creates a complex deformity of the hip that can result in cam type of femoroacetabular impingement (FAI), which may in turn lead to the early development of osteoarthritis of the hip. The purpose of this study was to evaluate the existing literature reporting on the efficacy of hip arthroscopic treatment of patients with FAI secondary to SCFE.

Objectives

To date, no study has considered the impact of acromial morphology on shoulder range of movement (ROM). The purpose of our study was to evaluate the effects of lateralization of the centre of rotation (COR) and neck-shaft angle (NSA) on shoulder ROM after reverse shoulder arthroplasty (RSA) in patients with different scapular morphologies.

Introduction

Femoroacetabular impingement(FAI) is a relatively common cause causes of hip pain and dysfunction in active young adults. The concept of FAI was popularized by Ganz et al in early 2000s. Surgical treatment for FAI has been widely employed over the last two decades. The long term outcome of femoroacetabular osteoplasty (FAO) and risk factors for long-term failure of FAO is less studied. The goal of this single surgeon series is to identify the long term outcome of FAO (minimum 10-year follow-up) and risk factors for surgical treatment failure in these patients.

The purpose of this study was to examine a cohort of patients with minor acetabular dysplasia features in order to identify the preoperative clinical characteristics and imaging findings that differentiate patients with hip instability from patients with impingement.

A retrospective cohort study of patients with borderline acetabular dysplasia was performed. All patients were identified by prospective radiographic evaluation with an LCEA between 20° and 25°. Multivariate statistical analyses were used to identify independent predictors of disease type.

Of the 143 hips in the cohort, 39.2% (n=56) had the diagnosis of instability, while 60.8% (n=87) had the diagnosis of impingement. The cohort included 109 females (76.2%) and 34 males (23.8%).

Hips with instability had a lower LCEA (21.8° vs. 22.8°; p<0.001), lower ACEA (23.3° vs. 26.6°; p=0.002), a higher AI (11.8° vs. 8.5°; p<0.001), and a lower maximum alpha angle (54.4° vs. 61.1°; p=0.001). The odds of instability increased 1.7 times for each one-degree decrease in LCEA, 1.4 times for each one-degree decrease in ACEA, and 1.1 times for each one-degree increase in acetabular inclination (all p0.003). Female sex was strongly associated with instability.

The instability subgroup had greater range of motion (IRF, 22.7° vs. 12.4°, p<0.001) and total arc of motion (IRF+ERF, 61.2° vs. 47.4°, p<0.001). We identified predictors of diagnosis including: acetabular inclination (1.49, p<0.001), ACEA (0.89, p=0.007), crossover sign (0.27, p=0.014), preoperative mHHS (0.96, p=0.014), IRF (1.10, p=0.001), and age (0.88, p=0.001).

Patients with symptomatic instability tend to have increased acetabular inclination, decreased ACEA, greater functional limitations, younger, greater IRF, while hips with impingement demonstrate the opposite trends.

Posterior extraarticular ischiofemoral hip impingement can be caused by high femoral torsion and is typically located between the ischium and the lesser trochanter. We asked if patients undergoing derotational femoral osteotomies for posterior FAI have (1) decreased hip pain and improved function and evaluated (2) subsequent surgeries and complications?

Thirty-three hips undergoing derotational femoral osteotomies between 2005 and 2016 were evaluated retrospectively. Of them 15 hips underwent derotational femoral osteotomies and 18 hips underwent derotational femoral osteotomies combined with varisation (neck-shaft angle >139°). Indication for derotational osteotomies was a positive posterior impingement test in extension and external rotation, high femoral torsion (48° ± 9) on CT scans and limited external rotation. Offset improvement was performed to avoid intraarticular impingement in hips with a cam-type FAI. All patients were female and mean followup was 3 ± 2 (1 – 11) years.

At latest followup the positive posterior and anterior impingement test decreased from preoperatively 100% to 5% (p< 0.001) and from preoperatively 85% to 30% (p< 0.001). The mean Merle d'Aubigné Postel score increased from 14 ± 1 (11 – 16) to 16 ± 1 (13 – 17) at latest followup (p< 0.001). At followup 32/33 hips had been preserved and one hip had been converted to a total hip arthroplasty (THA). In two hips (6%) revision osteosynthesis was performed for delayed healing of the femoral osteotomy.

Derotational femoral osteotomies for the treatment of posterior extraarticular ischiofemoral impingement caused by high femoral torsion result in decreased hip pain and improved function at midterm followup but had 6% delayed healing rate requiring revision surgery.

To confirm whether developmental dysplasia of the hip has a risk of hip impingement, we analysed maximum ranges of movement to the point of bony impingement, and impingement location using three-dimensional (3D) surface models of the pelvis and femur in combination with 3D morphology of the hip joint using computer-assisted methods. Results of computed tomography were examined for 52 hip joints with DDH and 73 normal healthy hip joints. DDH shows larger maximum extension (p = 0.001) and internal rotation at 90° flexion (p < 0.001). Similar maximum flexion (p = 0.835) and external rotation (p = 0.713) were observed between groups, while high rates of extra-articular impingement were noticed in these directions in DDH (p < 0.001). Smaller cranial acetabular anteversion (p = 0.048), centre-edge angles (p < 0.001), a circumferentially shallower acetabulum, larger femoral neck anteversion (p < 0.001), and larger alpha angle were identified in DDH. Risk of anterior impingement in retroverted DDH hips is similar to that in retroverted normal hips in excessive adduction but minimal in less adduction. These findings might be borne in mind when considering the possibility of extra-articular posterior impingement in DDH being a source of pain, particularly for patients with a highly anteverted femoral neck.

Cite this article: Bone Joint J 2014;96-B:580–9.

Introduction

Iliopsoas tendonitis after total hip arthroplasty (THA) can be a considerable cause of pain and patient dissatisfaction. The optimal cup position to avoid iliopsoas tendonitis has not been clearly established. Implant designs have also been developed with an anterior recess to avoid iliopsoas impingement. The purpose of this cadaveric study was to determine the effect of cup position and implant design on iliopsoas impingement.

Introduction

Highly crosslinked, ultra-high molecular weight polyethylene (HXLPE) acetabular liners inherently have a risk of fatigue failure associated with femoral neck impingement. One of the potential reasons for liner failure was reported as crosslinking formulations of polyethylene, increasing the brittleness and structural rigidity. In addition, the acetabular component designs greatly affect the mechanical loading scenario, such as the offset (lateralized) liners with protruded rim above the metal shells, which commonly induce a weak resistance to rim impingement. The purpose of the present study was to compare the influence of the liner offset length on the impingement resistance in the annealed (first generation) and vitamin E-blended (second-generation) HXLPE liners with a commercial design.

Introduction

Iliopsoas impingement is a well described cause of groin pain after direct anterior total hip arthroplasty (THA). We proposed to evaluate the incidence, natural history and response to treatment of iliopsoas impingement after direct anterior total hip arthroplasty.

Since the Oxford knee was first used unicompartmentally in 1982, a small number of bearings have fractured. Of 14 retrieved bearings, we examined ten samples with known durations in situ (four Phase 1, four Phase 2 and two Phase 3). Evidence of impingement and associated abnormally high wear (> 0.05 mm per year) as well as oxidation was observed in all bearings. In four samples the fracture was associated with the posterior radio-opaque wire. Fracture surfaces indicated fatigue failure, and scanning electron microscopy suggested that the crack initiated in the thinnest region. The estimated incidence of fracture was 3.20% for Phase 1, 0.74% for Phase 2, 0.35% for Phase 3, and 0% for Phase 3 without the posterior marker wire. The important aetiological factors for bearing fracture are impingement leading to high wear, oxidation, and the posterior marker wire. With improved surgical technique, impingement and high wear should be prevented and modern polyethylene may reduce the oxidation risk. A posterior marker wire is no longer used in the polyethylene meniscus. Therefore, the rate of fracture, which is now very low, should be reduced to a negligible level.

Background

The goal of this study was (1) to investigate the relationships between the bony contours of the knee and the popliteus tendon before and after TKA and (2) to analyse the influence of implant sizing. Our hypothesis was that an apparently well-sized prosthesis, will modify the position or the tracking of popliteus tendon.

Introduction

Geometric variations of the hip joint can give rise to repeated abnormal contact between the femur and acetabular rim, resulting in cartilage and labrum damage. Population-based geometric parameterisation can facilitate the flexible and automated in silico generation of a range of clinically relevant hip geometries, allowing the position and size of cams to be defined precisely in three dimensions. This is advantageous compared to alpha angles, which are unreliable for stratifying populations by cam type. Alpha angles provide an indication of cam size in a single two-dimensional view, and high alpha angles have been observed in asymptomatic individuals.

Parametric geometries can be developed into finite element models to assess the potential effects of morphological variations in bone on soft tissue strains. The aim of this study was to demonstrate the capabilities of our parameterisation research tool by assessing impingement severity resulting from a range of parametrically varied femoral and acetabular geometries.

Background

The acetabular labrum provides sealing function and a degree of hip joint stability. Previous early(16 month) and mid-term(mean 3.5 years) follow-up of this cohort reported better patient related outcome measures in the refixation group.

INTRODUCTION

Femoral stem impingement can damage an acetabular liner, create polyethylene wear, and potentially lead to dislocation. To avoid component-to-component impingement, many surgeons aim to align acetabular cups based on the “Safe Zone” proposed by Lewinnek. However, a recent study indicates that the historical target values for cup inclination and anteversion defined by Lewinnek et al. may be useful but should not be considered a safe zone. The purpose of this study was to determine the effect of altering femoral head size on hip range-of-motion (ROM) to impingement.

In approximately 20 years, surgical treatment of femoro-acetabular impingement (FAI) has been widely accepted, and its indications refined. However, the current approach of the disease prevents a good understanding of its pathophysiology, and numerous uncertainties remain. Comprehending inter-individual spine-hip relations (SHRs) can further clarify the pathophysiology of impingement, and explain occasional surprising mismatch between clinical assessment and imaging or intraoperative findings. The rational is simple, the more the spino-pelvic complex is mobile (sagittal ROM) and the more the hip is protected against hip impingement but would probably become at risk of spine-hip syndrome if the spino-pelvic complex comes to degenerate. Grouping patients based on their spine-hip relation can help predict and diagnose hip impingement, and assess the relevance of physiotherapy. With the proposed new classification of FAIs, every patient can be classified in homogeneous groups of complexity of treatment. The primary aim of this paper is to raise awareness of the potential impact that the spine-hip relations have on the hip impingement disease. Two new classifications are proposed, for FAIs and SHRs that can help surgeons in their comprehension, and could be beneficial in clinical and research areas.

To characterize the quality of flap tissues and the resident cells in order to provide a scientific rationale for reattaching flap tissues during surgery.

11 acetabular chondral flaps and 3 non-delaminated cartilage samples were resected during open hip surgeries and the anatomical orientation was marked. The viability was measured in 7 flaps with Live Dead staining and the distribution of the extracellular matrix components was investigated in 7 oriented flaps by histology. The chondrogenic potential of the residing cells (P2) was investigated via pellets assays (5 flaps). Their capacity to outgrow from flap particles was tested upon encapsulation in 4mm-diameter fibrin glue discs (6 flaps).

The viability in flaps was 49.4 ± 6.5 % compared to 70.6 ± 8.2 % in non-delaminated cartilage, (not significant). Histology showed a progression of fibrillation from the delaminated side towards the site of attachment. This degraded state correlated with the capacity of the cells to outgrow, with 60.6 ± 33 % of the gel area covered by migrating cells after 4 weeks in culture. However, the cells in flaps showed a decreased chondrogenic potential than chondrocytes from non-delaminated cartilage.

Our findings indicate that flaps contain viable cells that can outgrow from the tissue due to the degraded state of the matrix. The poor chondrogenic property of the cells suggests they are unlikely to produce enough matrix to provide a solid attachment of the delaminated tissue upon migration.

Introduction

Reverse Shoulder Arthroplasty (RSA) is recognized to be an effective solution for rotator cuff deficient arthritic shoulders, but there are still concerns about impingement and range of motion (ROM). Several RSA biomechanical studies have shown that humeral lateralization can increase ROM in planar motions (e.g. abduction). However, there is still a debate whether humeral lateralization should be achieved with a larger sphere diameter or by lateralizing the center of rotation (COR). The latter has shown to decrease the deltoid moment arm and increase shear forces, where the former may pose challenges in implanting the device in small patients. The aim of this study was to evaluate how humeral lateralization achieved by varying COR lateral offset and glenosphere diameter in a reverse implant can affect impingement during activities of daily living (ADLs).

Femoroacetabular impingement (FAI) is a significant cause of osteoarthritis in young active individuals but the pathophysiology remains unclear. Increasing mechanistic studies point toward an inflammatory component in OA. This study aimed to characterise inflammatory cell subtypes in FAI by exploring the phenotype and quantification of inflammatory cells in FAI versus OA samples.

Ten samples of labrum were obtained from patients with FAI (confirmed pathology) during open osteochondroplasty or hip arthroscopy. Control samples of labrum were collected from five patients with osteoarthritis undergoing total hip arthroplasty. Labral biopsies were evaluated immunohistochemically by quantifying the presence of macrophages (CD68 and CD202), T cells (CD3), mast cells (mast cell tryptase) and vascular endothelium (CD34).

Labral biopsies obtained from patients with FAI exhibited significantly greater macrophage, mast cell and vascular endothelium expression compared to control samples. The most significant difference was noted in macrophage expression (p<0.01). Further sub typing of macrophages in FAI using CD202 tissue marker revealed and M2 phenotype suggesting that these cells are involved in a regenerate versus a degenerate process. There was a modest but significant correlation between mast cells and CD34 expression (r=0.4, p<0.05) in FAI samples.

We provide evidence for an inflammatory cell infiltrate in femoroacetabular impingement. In particular, we demonstrate significant infiltration of mast cells and macrophages suggesting a role for innate immune pathways in the events that mediate hip impingement. Further mechanistic studies to evaluate the net contribution and hence therapeutic utility of these cellular lineages and their downstream processes may reveal novel therapeutic approaches to the management of early hip impingement.

Femoroacetabular impingement is defined as abnormal abutment between the femoral head, or the femoral head-neck junction, and the acetabulum. It is now established that FAI is a major etiological factor in the development of osteoarthritis (OA) of the hip.

FAI is increasingly recognized as a cause of hip pain in young active individuals. Clinical features of FAI include pain in the groin but this may also be felt in the gluteal region, trochanteric region, or in the thigh. Symptoms most commonly begin as an intermittent discomfort, often during or following periods of repetitive hip motion e.g. running, walking, progressing to more constant and intense pain. Stiffness is common, with reductions in the range of hip flexion, and internal rotation in particular. Patients may also complain of clicking, popping, or snapping sensations in the affected hip.

Operative treatment of FAI is principally aimed at removing cam lesions and increasing femoral head-neck offset (osteochondroplasty), and treating associated soft tissue lesions such as labral tears. Acetabular recession with labral reattachment is increasingly used for pincers lesions but great care is needed to ensure that the overall coverage of the hip is not reduced. As proficiency with arthroscopic techniques has improved, arthroscopic osteochondroplasty and labral debridement/repair has become increasingly popular for the treatment for FAI, with promising functional results in a range of studies.

150 consecutive patients who underwent hip arthroscopy for CAM type FAI with minimum 1 year follow up were prospectively studied. Patient satisfaction, non-arthritic hip score, re-operations and conversion to arthroplasty were analysed.

There were a total of 90 males and 60 females. The average age group was 32 years (27 to 46 years). All patients underwent osteoplasty of the CAM lesion and stabilisation/ repair of the labral tears. A comparison of pre procedure non arthritic hip scores with the scores at latest follow up (minimum 1 year, maximum 3 years) showed a significant improvement (56 vs 86; p <0.01). There were 2 re operations for unresolved symptoms and 1 conversion to arthroplasty for continued pain associated with significant loss of articular cartilage. Perineal numbness was noted in 9 patients all of which resolved. No other major complications were noted in this series. Hip impingement symptoms resolved in all cases and a good (20 %) to excellent (75%) outcome was reported.

Arthroscopic management of CAM type FAI is associated with subjective and objective improvement in hip function at early follow up. Longer follow-up is necessary to analyse the ability of this procedure to arrest progression of degenerative hip disease.

Femoroacetabular impingement (FAI) is a significant cause of osteoarthritis in young active individuals but the pathophysiology remains unclear. Increasing mechanistic studies point toward an inflammatory component in OA. This study aimed to characterise inflammatory cell subtypes in FAI by exploring the phenotype and quantification of inflammatory cells in FAI versus OA samples.

Ten samples of labrum were obtained from patients with FAI (confirmed pathology) during open osteochondroplasty or hip arthroscopy. Control samples of labrum were collected from five patients with osteoarthritis undergoing total hip arthroplasty. Labral biopsies were evaluated immunohistochemically by quantifying the presence of macrophages (CD68 and CD202), T cells (CD3), mast cells (mast cell tryptase) and vascular endothelium (CD34).

Labral biopsies obtained from patients with FAI exhibited significantly greater macrophage, mast cell and vascular endothelium expression compared to control samples. The most significant difference was noted in macrophage expression (p<0.01). Further sub typing of macrophages in FAI using CD202 tissue marker revealed and M2 phenotype suggesting that these cells are involved in a regenerate versus a degenerate process. There was a modest but significant correlation between mast cells and CD34 expression (r=0.4, p<0.05) in FAI samples.

We provide evidence for an inflammatory cell infiltrate in femoroacetabular impingement. In particular, we demonstrate significant infiltration of mast cells and macrophages suggesting a role for innate immune pathways in the events that mediate hip impingement. Further mechanistic studies to evaluate the net contribution and hence therapeutic utility of these cellular lineages and their downstream processes may reveal novel therapeutic approaches to the management of early hip impingement.

Introduction

Range of motion (ROM) simulation of the hip is useful to understand the maximum impingement free ROM in total hip arthroplasty (THA). In spite of a complex multi-directional movement of the hip in daily life, most of the previous reports have evaluated the ROM only in specific directions such as flexion-extension, abduction-adduction, and internal - external rotation at 0° or 90° of hip flexion. Therefore, we developed ROM simulation software (THA analyzer) to measure impingement free ROM in any positions of the hip. Recent designs of the hip implants give a wider ROM by increasing the head diameter and then, bone to bone impingement can be a ROM limit factor particularly in a combination of deep flexion, adduction and internal rotation of the hip. Therefore, the purpose of this study were to observe an individual variation in the pattern of the bone impingement ROM in normal hip bone models using this software, to classify the bone impingement ROM mapping types and to clarify the factors affecting the bone impingement type.

Background

It is not always clear why some patients experience recurrent dislocation following total hip arthroplasty (THA). In order to plan appropriate revision surgery for such patients, however, it is important to understand the specific biomechanical basis for the dislocation. We have developed a novel method to analyse the biomechanical profile of the THA, specifically to identify edge loading and prosthetic impingement, taking into account spinopelvic mobility. In this study we compare the results of this analysis in THA patients with and without recurrent dislocation.

Aims

Asphericity of the femoral head-neck junction is common in cam-type femoroacetabular impingement (FAI) and usually quantified using the alpha angle on radiographs or MRI. The aim of this study was to determine the natural alpha angle in a large cohort of patients by continuous circumferential analysis with CT.

To determine the mechanisms and extents of popliteus impingements before and after TKA and to investigate the influence of implant sizing. The hypotheses were that (i) popliteus impingements after TKA may occur at both the tibia and the femur and (ii) even with an apparently well-sized prosthesis, popliteal tracking during knee flexion is modified compared to the preoperative situation.

The location of the popliteus in three cadaver knees was measured using computed tomography (CT), before and after implantation of plastic TKA replicas, by injecting the tendon with radiopaque liquid. The pre- and post-operative positions of the popliteus were compared from full extension to deep flexion using normosized, oversized and undersized implants (one size increments).

At the tibia, TKA caused the popliteus to translate posteriorly, mostly in full extension: 4.1mm for normosized implants, and 15.8mm with oversized implants, but no translations were observed when using undersized implants. At the femur, TKA caused the popliteus to translate laterally at deeper flexion angles, peaking between 80º-120º: 2.0 mm for normosized implants and 2.6 mm with oversized implants. Three-dimensional analysis revealed prosthetic overhang at the postero-superior corner of normosized and oversized femoral components (respectively, up to 2.9 mm and 6.6 mm).

A well-sized tibial component modifies popliteal tracking, while an undersized tibial component maintains more physiologic patterns. Oversizing shifts the popliteus considerably throughout the full arc of motion. This study suggests that both femoro- and tibio-popliteus impingements could play a role in residual pain and stiffness after TKA.

The outcomes of hip arthroscopy in the treatment of dysplasia are variable. Historically, arthroscopic treatment of severe dysplasia (lateral center-edge angle [LCEA] < 18°) resulted in poor outcomes and iatrogenic instability. However, in milder forms of dysplasia, favorable outcomes have been reported. The purpose of this study was to compare outcomes following hip arthroscopy for femorocetabular impingement (FAI) in borderline dysplastic (BD) patients compared with a control group of non-dysplastic patients.

Between March 2009 and July 2012, a BD group (LCEA 18°–25°) of 46 patients (55 hips) was identified. An age and sex-matched control group of 131 patients (152 hips) was also identified (LCEA 25°–40°). Patient-reported outcome scores, including the Modified Harris Hip Score (mHHS), the Hip Outcome Score-Activity of Daily Living (HOS-ADL), the Sport-specific Subscale (HOS-SSS), and the International Hip Outcome Tool (iHOT-33), were collected pre-operatively, at 1, and 2 years.

The mean LCEA was 22.4 ± 2.0° (range, 18.4°–24.9°) in the BD group and 31.0 ± 3.1° (range, 25.4°–38.7°) in the control group (p<0.001). The mean preoperative alpha angle was 66.3 ± 9.9° in the BD group and 61.7 ± 13.0° in the control group (p=0.151). Cam decompression was performed in 98.2% and 99.3% of cases in the BD and control groups. Labral repair was performed in 69.1% and 75.3% of the BD and control groups respectively, with 100% of patients having a complete capsular closure performed in both groups. At a mean follow-up of 31.3 ± 7.6 months (range, 23.1–67.3) in unrevised patients and 21.6 ± 13.3 months (range 4.7–40.6) in revised patients, there was significant improvement (p<0.001) in all patient reported outcome scores in both groups. Multiple regression analysis did not identify any significant differences between groups. Importantly, female sex did not appear to be a predictor for inferior outcomes. Two patients (4.3%) in the BD group and six patients (4.6%) in the control group required revision arthroscopy during the study period.

Favorable outcomes can be expected following the treatment of impingement in borderline dysplastics when labral refixation and capsular closure are performed, with comparable outcomes to non-dysplastic patients. Further follow-up in larger cohorts is necessary to prove the durability and safety of hip arthroscopy in this challenging group and to further explore potential gender-related differences in outcome.

Femoroacetabular impingement (FAI) syndrome is one of the significant reasons for hip pain, loss of ROM at hip joint and developing early osteoarthritis at young active adults. FAI is not a new term and it is treated successfully with open surgical techniques. Some disadvantages of open surgical tecniques has lead orthopedists to develop arthroscopic tecniques.

At this study, we aimed to assess the effectiveness of arthroscopy at the treatment of FAI. We included 25 patients (19 male, 6 female) and evaluated retrospectively which has gone under arthroscopic surgery for the treatment of FAÄ° at Gulhane Military Medicine Academy, Department of Orthopedics and Traumatology and Ankara Koru Hospital, Department of Orthopedics and Traumatology between January 2009 and May 2012.

We have evaluated modified Harris Hip Score and Visual Analogue Score (VAS) preoperatively and postoperatively at all of our patients. Also we have evaluated, hip internal rotation and flexion range of motions clinically. Mean preoperative Harris Hip Score was 68,52 (range 55–76), mean postoperative score was 88,84 (range 72–98). Mean preoperative flexion ROM was 87, 6 (range 80–95) and 108,2 (range 90–120) postoperatively. Also 4,4 (range 0–5) degrees of mean preoperative internal rotation ROM increased to 19,80 range (10–30) degrees postoperatively. Mean preoperative alpha angle was 76,76 (range 60–90) and it was decreased to 41,76 (range 34–48) postoperatively. Mean preoperative visual analog score were decreased from 8, 63 to 2,8 postoperatively.

We had to perform o second look arthroscopy to a patient because of inadequate resection. Also femoral neck stres fracture occured at a patient probably due to early weight bearing. Transient sciatic nevre neuropraxy occured at a 3 patients and, transient ankle pain (approximately 6 weeks) had occured at 2 patients due to traction. Loss of sensation has occured at a patient due to lateral femoral cutaneus nevre injury during portal placement.

With these results, we assessed that arthroscopic treatment of the FAI syndrome is succesfull with minor complications comperable to open procedures.

The pathology of the posterior acetabular legion in femoroacetabular impingement (FAI) syndrome, so called “contre-coup region”, is still unclear. ¹⁸F-fluoride positron emission tomography (PET) is a functional imaging modality, which reflects the osteoblast activity. Recent technological advances in PET combined with computed tomography (CT) imaging allowed us to obtain detailed 3-dimensional (3D) morphological information. We evaluated the abnormal uptake of ¹⁸F-fluoride PET/CT on posterior acetabular lesion in FAI syndrome cases. We enrolled forty-one hips from 41 patients who were diagnosed as FAI syndrome and were performed ¹⁸F-fluoride PET/CT between October 2014 and October 2016. In each hip, the maximum standardized uptake value (SUV_max) on the posterior acetabular was measured. The cases were divided into 4 groups; cam-type (11 cases), pincer-type (7), combined-type (11), dysplastic developmental hip (DDH) with cam morphology (12). The average SUV_max of the pincer-type was significantly smaller than that of the other 3 groups (p < .05). The percentage of the cases with SUV_max ≥ 6 was 81.8% in cam-type, 28.6% in pincer-type, 90.9% in combined-type, 91.7% in DDH with cam morphology. Furthermore, the average degree of α angle of the cases of SUV_max ≥ 6 was significantly higher than that of the cases of SUV_max < 6 (p = .005). Although actual biomechanical mechanism in contre-coup region is still controversial, this result indicated that the cam morphology related to the posterior acetabular lesion with accelerated bone metabolism.

Background

Shoulder impingement syndrome (SIS) is a common debilitating condition, treated across multiple health disciplines including Orthopaedics, Physiotherapy, and Rheumatology. There is little consistency in diagnostic criteria with ‘Shoulder impingement syndrome’ being used for a broad spectrum of complex pathologies. We assessed patterns in diagnostic procedures for SIS across multiple disciplines.

Hip impingement causes clinical problems for both the native hip, where labral or chondral damage can cause severe pain, and in the replaced hip, where subluxation can cause squeaking/metallosis through edge loading, or can cause dislocation. There is much research into bony/prosthetic hard impingements showing that anatomical variation/component mal-positioning can increase the risk of impingement. However, there is a lack of basic science describing the role of the hip capsule and its intertwined ligaments in restraining range of motion, ROM, and so it is unclear if careful preservation/repair of the capsular ligaments would offer clinical benefits to young adults, or could also help prevent edge loading in addition to reducing the postoperative dislocation rate in older adults.

This in-vitro study quantifies the ROM where the capsule passively stabilises the hip and compares this to hip kinematics during daily activities at risk for hip subluxation.

Ten cadaveric left hips were skeletonised preserving the joint capsule and mounted in a testing rig that allowed application of loads, torques and rotations in all six-degrees of freedom (Figure 1). At 27 positions encompassing a complete hip ROM, the passive rotation resistance of each hip was recorded. The gradient of the torque-rotation profiles was used to quantify where the capsule is taut/slack and after resecting the capsule, where labral impingement occur. The ROM measurements were compared against hip kinematics from daily activities.

The capsule tightly restrains the hip in full flexion/extension with large slack regions in mid-flexion. Whilst ligament recruitment varies throughout hip ROM, the magnitude of restraint provided is constant (0.82 ± 0.31 Nm/degree). This restraint acts to prevent or reduce loading of the labrum in the native hip (Figure 2). The measured passive rotational stability envelope is less than clinical ROM measurements indicating the capsule does provide restraint to the joint within a relevant ROM. Activities such as pivoting, stooping, shoe tying and rolling over in bed all would recruit the capsular ligaments in a stabilising role.

The fine-tuned anatomy of the hip capsule provides a consistent contribution to hip rotational restraint within a functionally relevant ROM for normal activities protecting the hip against impingement. Capsulotomy should be kept to a minimum and routinely repaired in the native hip to maintain natural hip mechanics. Restoring its native function following hip replacement surgery may provide a method to prevent subluxation and edge loading in the replaced hip.

Purpose

To determine the differences of biomechanical properties in three conditions including 1) native cam deformity 2) cam deformity with incomplete resection and 3) cam deformity with complete resection.

Introduction

Ultra-high molecular weight polyethylene (UHMWPE) is the sole polymeric material currently used for weight- bearing surfaces in total joint replacement. However, the wear of UHMWPE and the polyethylene wear debris generated in the human body after total joint replacement cause serious clinical and biomechanical reactions.

Therefore, the wear phenomenon of UHMWPE in total joint replacement is now recognized as one of the major factors restricting the longevity of these implants. In order to minimize the wear of UHMWPE and to improve the longevity of artificial joints, it is necessary to clarify the factors influencing the wear mechanism of UHMWPE.