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

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

Introduction. Hips following in-situ pinning for slipped capital femoral epiphysis (SCFE) have an altered morphology of the proximal femur with cam type deformity. This deformity can result in femoroacetabular impingement and early joint degeneration. The modified Dunn procedure allows to reorientate the slipped epiphysis to restore hip morphology and function. Objectives. To evaluate (1) hip pain and function, (2) 10-year survival rate and (3) subsequent surgeries and complications in hips undergoing modified Dunn procedure for SCFE. Methods. Between April 1998 and December 2005 we performed the modified Dunn procedure for 43 patients (43 hips) with SCFE. Twenty-five hips (58) presented with an acute or acute on chronic slip. The mean slip angle was 43° (range, 15° – 80°). A majority of 53% of procedures were performed in male patients and the mean age at operation was 13 years (10 – 19 years). We could followup all except one hip (followup of 5.5 year) for a minimum of 10 years (mean followup 13 [10 – 18 years]). We used the anterior impingement test to assess pain and the Merle d'Aubigné- ostel score to assess function. Survivorship calculation was performed using the method of Kaplan and Meier and any of the following factors as a definition of failure: radiographic evidence of worsening osteoarthritis (OA), or a Merle d'Aubigné-Postel score less than 15. Results. (1) The prevalence of a positive anterior impingement test decreased from 100% to 16% (p<0.001). The mean Merle d'Aubigné-Postel score improved from 13 (7 – 14) to 17 (14 – 18) at most recent followup (p<0.001). (2) Four hips (9%) showed progression of OA and three hips (7%) had a Merle d'Aubigné-Postel score of less than 15 at most recent followup. This resulted in a 93% survival rate at 10-year followup. (3) No hip developed avascular necrosis. Five hips (12%) had complications with reosteosynthesis due to screw breakage or nonunion. Another nine hips (21%) had subsequent surgeries including acetabular rim trimming / offset creation in 5 hips and screw removal in 4 hips. Conclusion. The modified Dunn procedure is a safe method to correct the morphology of the proximal femur in hips with SCFE. Ninety-free percent of the hips showed no progression of OA and a good clinical result at the 10-year followup. Twelve percent required revision surgery for complications all including screw breakage with nonunion of the greater trochanter

BACKGROUND. Early dislocation is a foremost complication of total hip arthroplasty through a postero-lateral approach. The extra-articular impingement of the anterior part of the great trochanter with ileum bone, with or without soft tissue interposition is a well recognized but underestimated etiopathogenetic cause reported in literature. In this retrospective study through the assessment of clinical and radiographic follow-up at a minimum of six months, the effectiveness of an antero- longitudinal osteotomy of the great trochanter for early dislocation prevention is evaluated. MATERIALS AND METHODS. 209 patients (48.3% males and 51,7% females) underwent a total hip arthroplasty from June 2011 to September 2015, with surgery being performed by the same surgeon. A modified posterolateral approach was used according to the tissue-sparing criteria, in all the cases an anterior longitudinal osteotomy of the great trochanter has been performed at 90° to the antiversion angle of the implant and aligned posteriorly with the prosthesis. All the patients underwent a clinical and radiological follow up at one, three, and six months. RESULTS. In this study, only one patient reported dislocation of THA. One patient suffered from a wound infection which was subsequently treated with antibiotics and had complete remission. All patients demonstrated a fast recovery of ROM and walking, starting from pre-op Harris Hip Score 42.24pts and obtaining a score of 81.52pts at three months, and 92.03 at six months post-op. After surgery and during the follow up period, there were no trochanteric fractures detected. DISCUSSION. The correct positioning of the implants, the head diameter, offset, soft tissues repair, absence of impingement, and patients compliance are all elements that define the prosthetic stability. Literature shows and incidence of primary total hip arthroplasty dislocation between 0.80% to 10%. The incidence of dislocation reported in a preliminary study in our Institute is 0.48%, demonstrating the effectiveness of the trochanteric osteotomy. CONCLUSIONS. The osteotomy of the great trochanter is an effective surgical technique used to decrease the anterior impingement and early dislocation incidence. It is particularly effective on patients with good compliance and correctly implanted prosthetic components

Introduction. Acetabular retroversion is an accepted cause of Pincer-type femoroacetabular impingement. There is increasing evidence that acetabular retroversion is rather a rotational abnormality of the pelvis than an overgrowth of the acetabular wall or even a dysplasia of the posterior wall. Initially, patients with a retroverted acetabulum were treated with an open rim trimming through a surgical hip dislocation (SHD) based on the early understanding of the pathomorphology. Theoretically, the reduction of the anterior wall can decrease the already small joint contact area in retroverted hips to a critical size. Based on the most recent literature, anteverting periacetabular osteotomy (PAO) seems to be the more appropriate surgical treatment. With this technique, the anterior impingement conflict can be treated efficiently without compromising the joint contact area. However, it is unknown whether this theoretical advantage in turn results in better mid term results of treatment. Objectives. We asked if anteverting PAO results in better clinical and radiographical mid term results compared to rim trimming through a surgical hip dislocation. Methods. We performed a retrospective comparative study based on 257 hips (221 patients) with symptomatic femoroacetabular impingement due to acetabular retroversion. Acetabular retroversion was defined by a cross-over sign, a posterior wall sign, and a positive ischial spine sign. We then formed two matched groups consisting of 73 hips undergoing open acetabular rim trimming and 54 hips with an anteverting periacetabular osteotomy. Patients with incomplete radiographic documentation, previous surgery, and hip dysplasia (LCE < 20°) were excluded. Some patients were excluded due to a matching process (Fig. 1). Patients were generally followed clinically and radiographically after two, five and ten years. A Kaplan-Meier survivorship analysis was performed using the following endpoints: a low clinical score, radiographic progression of osteoarthritis, and/or the conversion to total hip arthroplasty. The Log Rank Score was used to compare the two survivorship curves. Results. Patients undergoing anteverting PAO for acetabular retroversion had a significantly increased survivorship (82%, 95% confidence interval, 72–91%) at seven years in comparison to open surgical rim trimming (63%, 95%CI, 49–76%, p<0.0001). The two survivorship curves are comparable for the first four years with a substantial drop for the rim trimming group after year five (Fig. 2). Conclusion. This study proofs for the first time that the theoretical advantages of anteverting periacetabular osteotomy in hips with symptomatic acetabular retroversion results in an increased survivorship at mid term follow-up in comparison to open rim trimming. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Introduction. Torsional deformities of the femur have been recognized as a cause of femoroacetabular impingement (FAI) and hip pain. High femoral antetorsion can result in decreased external rotation and a posterior FAI, which is typically located extraarticular between the ischium and trochanter minor. Femoral osteotomies allow to correct torsional deformities to eliminate FAI. So far the mid-term clinical and radiographic results in patients undergoing femoral osteotomies for correction of torsional deformities have not been investigated. Objectives. Therefore, we asked if patients undergoing femoral osteotomies for torsional deformities of the femur have (1) decreased hip pain and improved function and (2) subsequent surgeries and complications?. Methods. We retrospectively evaluated 21 hips (18 patients) who underwent femoral osteotomies for correction of torsional deformities between April 2005 and October 2014. Twenty hips with excessive femoral antetorsion (47.7° ± 8.6°, range 32° – 65°) had a derotational femoral osteotomy. One hip with decreased femoral antetorsion of 11° underwent rotational femoral osteotomy. Previous surgery were performed in 43% of the hips including hip arthroscopy (5 hips), acetabular osteotomy (2 hips), open reduction for high dislocation (2 hips), surgical hip dislocation (2 hips) and varus intertrochanteric osteotomy (1 hip). In 10 hips a concomitant offset correction and in 5 hips a concomitant periacetabular osteotomy were performed. The mean followup was 3.6 ± 2.3 (1 – 10) years. One patient (one hip) died from a cause unrelated to surgery at the 2 year follow-up. We used the anterior and posterior impingement test to evaluate pain. Function was assessed using the Merle d'Aubigné Postel score, WOMAC, UCLA activity score and Harris hip score. Results. The incidence of a positive anterior impingement test decreased from preoperatively 85% to 29% at latest follow-up (p<0.001). The incidence of a positive posterior impingement test decreased from preoperatively 90% to 5% at latest follow-up (p<0.001). The mean Merle d'Aubigné Postel score increased from 13 ± 2 (11 – 16) to 16 ± 1 (13 – 17) at latest followup (p<0.0001). For the WOMAC, UCLA and Harris hip score no preoperative values existed but at latest followup they all showed fair to good values with a mean WOMAC score of 14 ± 15 (1 – 50), UCLA score of 6 ± 1 (3 – 8) and Harris hip score of 77 ± 13 (47 – 96). Subsequent surgeries included hardware removal in 14 hips (66%) and hip arthroscopy with offset creation in 1 hip. Complications occurred in 5 hips (24%) all graded Grade III according to Sink and included conversion to total hip arthroplasty in 1 hip, reosteosynthesis due to pseudarthrosis in 3 hips and hip arthroscopy for adhesiolysis in 3 hips. Conclusion. Femoral osteotomies for the treatment of torsional deformities of the femur result in decreased pain and improved function in patients with FAI. However, these procedures are associated with a complication rate of 24% which is mainly due to pseudarthrosis and intraarticular adhesions in patients with concomitant offset correction

Aim. Alumina ceramic on ceramic bearings in total hip arthroplasty (THA) may reduce the prevalence of osteolysis due to its properties of low wear and chemical inertness. This is critical in the younger patient population as they place increased demands over a longer period. This study reports on the clinical and radiographic outcomes of a series of modern cementless ceramic on ceramic THA at a minimum of 10 years in this younger group. Method. A series of 120 consecutive third generation ceramic cementless THA were performed at a single centre in 110 patients from 1997 to 1999. The average age of the patients at the time of surgery was 45 years (20 to 55 years). All procedures were carried out via the posterior approach using the same implant by the two senior authors. Results. At 10 years, 4 patients had died and 6 were lost to follow-up (5%). The mean Harris Hip Score was 94.7 points. All surviving implants analysed radiographically had evidence of stable bony ingrowth, with no cases of osteolysis. Wear rates were undetectable. There were 3 revisions (2.5%). One stem was revised following periprosthetic fracture, one stem was revised to facilitate a femoral shortening osteotomy. One cup was revised for anterior impingement causing psoas tendonitis. There was one incident of intraoperative ceramic liner chipping, which was changed without complication. There were no postoperative bearing fractures. Two patients reported intermittent squeaking at extreme hip flexion and internal rotation, the hips otherwise functioned well. The survival for both components with revision for any cause was 97.5%. Conclusion. Alumina ceramic on ceramic bearings in cementless primary THA in this series have resulted in good clinical and radiographic outcomes with low wear rates and excellent function in the demanding younger patient group at 10 years

Background. The femoral head center shift on reduction time in total hip arthroplasty (THA) causes alteration of the muscle tension around the hip joint. Many studies about the shift of the femoral head in the cranio-caudal direction or medio-lateral direction on coronal plane have been reported. It has been known widely that the shift on these directions influence tension of the abductor muscle around the hip joint. Nevertheless few studies about the three-dimensional shift including the antero-posterior direction have been reported. Purpose. The purpose of this study is to evaluate the three-dimensional shift of the femoral head center in THA using three-dimensional THA templating software. Subjects & Methods. The subjects of this study were 156 primary THA cases of 143 patients. Using CT-based three-dimensional THA templating software ZedHip® (LEXI, Tokyo Japan), simulation of optimal implantation was performed on each THA case. On case which has over anteverted or less anteverted femoral neck, a stem which has modular neck system was selected to adjust anteversion of the femoral neck. The three-dimensional shift of the femoral head center on reduction time was calculated with ZedHip®. The three-dimensional shift was resolve into cranio-caudal, medio-lateral and antero-posterior direction (Fig. 1). Furthermore the correlation between the amount of the shift and hip joint deformity was investigated. Results. The average amount of the shift on cranio-caudal direction was 9.9mm to caudal side, on medio-lateral direction was 3.1mm to medial side and on antero-posterior direction was 2.6mm to posterior side. The average total amount of three-dimensional shift was 12.9mm (Fig. 2). On Crowe type 1 hips in 88 cases, the average shift to posterior side was 3.2mm, on Crowe type 2 in 20 cases was 3.7mm and on Crowe type 3 in 13 cases was 4.0mm. Among them there was no significant difference (Fig. 3). Conclusion. At THA surgery, the femoral head center shifted three-dimensionally and the maximum amount of shift on antero-posterior direction was 16.6mm to posterior side. There was no correlation between these amounts of the shift on antero-posterior direction and anatomical deformity of the hip joint. It is important to understand the shift of the femoral head center for predicting the alteration of muscle tension around the hip joint. The shift on antero-posterior direction influences the tension of iliopsoas muscle and there is a possibility that the shift to posterior side causes anterior iliopsoas impingement after THA surgery

Introduction. Dual-mobility (DM) liners provide increased range of motion and stability. However, large head diameters have been associated with anterior hip pain due to impingement with surrounding soft-tissues, particularly the iliopsoas. Further, during hip extension the liner can get trapped due to anterior soft-tissue impingement that resists rotation being imparted to the liner from posterior stem-liner contact. Over time this can cause liner rim damage, leading to intra-prosthetic dislocation of the small diameter inner head. To address this, an anatomically contoured dual mobility (ACDM) liner was designed to reduce the volume of the liner below the equator that can interact with soft-tissues (Fig. 1). In this study, we utilized finite element analysis to evaluate tendon-liner contact pressure and tendon stresses with ACDM and conventional designs during hip extension, wherein the posterior edge of liner is in contact with the stem while the anterior edge is exposed to the soft-tissue. Methods. The average uniaxial stiffness (350 N/mm), and average dimensions (width × thickness = 14mm × 4mm) of 10 cadaver psoas tendon samples were determined in a separate study. The iliopsoas tendon was modelled as a Yeoh hyper-elastic material, and the material constants were tuned to match the experimental uniaxial test data. Cadaver specific FEA models were created for 5 specimens (10 hips) using computed tomography (CT) scans. The implant components were modeled as being rigid relative to the iliopsoas tendon. The iliopsoas tendon was modelled as extending from its insertion point on the lesser trochanter to the psoas notch on the pelvis for hip flexion angles of −15°, 0°, 15° and 30°. Appropriately sized DM components were implanted virtually for each specimen. Once placed in its proper position, the liner was rotated about the flexion axis until it contacted the stem posteriorly to represent its orientation during hip extension (Fig. 2). A 500N tensile load was applied to the iliopsoas tendon and the average/max stresses within the tendon, and average/max contact pressures between the tendon and liner were measured. Results. At all hip flexion angles from −15° to 30°, the tendon-liner contact pressure and tendon stresses were lower with the ACDM liners compared to the conventional liner. Contact pressure and tendon stress decreased for both liner designs with increasing hip flexion angle. At −15° flexion angle, the average contact pressure was 42.3% lower (0.36Mpa), and the maximum contact pressure was 45.1% (8.5Mpa lower), with the ACDM compared to conventional liner design. Similarly, at −15° flexion angle the average vonMises pressure in the tendon was 32.5% lower (14.8Mpa), and the maximum vonMises stress in the tendon was 55.7% (159Mpa lower) with the ACDM design. (Fig 3). Discussion. This study utilized cadaver specific FEA models to evaluate interaction between the iliopsoas tendon and conventional and ACDM liners during hip extension. The results showed a notable reduction in contact pressure and tendon stress resulting from reduced volume and more soft-tissue friendly profile of the ACDM design. Thus, the ACDM design may be able to reduce undesirable soft-tissue interaction with dual mobility liners

Introduction. Dual Mobility (DM) implants have gained popularity for the treatment and prevention of hip dislocation, with increased stability provided by a large diameter mobile liner. However, distal regions of the liner can impinge on soft-tissues like hip capsule and iliopsoas, leading to anterior hip pain. Additionally, soft-tissue impingement may trap the mobile liner, leading to excessive loading of the liner rim, from engagement with the femoral stem, and subsequent intra-prosthetic dislocation. The hypothesis of this study was that reducing the liner profile below the equator (contoured design) can mitigate soft-tissue impingement without compromising inner-head pull-out resistance and overall hip joint stability (Fig. 1). Methods. The interaction of conventional and contoured liners with anterior soft-tissues was evaluated in 10 cadaveric hips (5 specimens; 2 male, 3 female; age 65 ± 10 yrs; liner diameter 42–48mm) via visual observation and fluoroscopic imaging. A metal wire was sutured to the deep fibers of the iliopsoas tendon/muscle, and metal wires were embedded in the mobile liners for fluoroscopic visualization (Fig. 2). All soft-tissue except the anterior hip capsule and iliopsoas was removed, and a rope was attached to the iliopsoas to apply tension along its natural orientation. Resistance to inner-head pull-out was evaluated via Finite Element Analysis (FEA) by simulating a full cycle of insertion of the inner head into the mobile liner and subsequent pullout. The femoral head, acetabular shell, and stem were modeled as rigid, while the mobile liner was modeled as plastically deformable. Hip joint stability was evaluated by dynamic simulations in for two dislocation modes: (A) Posterior dislocation (at 90° hip flexion) with internal hip rotation; (B) Posterior dislocation (starting at 90° flexion) with combined hip flexion and adduction. A 44 mm diameter conventional and a 44 mm contoured liner were evaluated during these tests. Results. The cadaver experiments showed that distal portion of conventional liners impinge on anterior hip capsule and iliopsoas at low flexion angles (<30°). Additionally, when the hip moved from flexion into extension, the liner motion was blocked between posterior neck engagement, and anterior soft-tissue impingement. In all hips, the soft-tissue impingement / tenting was significantly reduced with contoured liners (Fig. 7). The change in tenting could be visualized as change in distance between the iliopsoas wire, and the contoured/conventional liners on sequential fluoroscopic images. The maximum reduction in iliopsoas tenting for a given specimen ranged from 1.8 mm to 5.5 mm. Additionally, the contoured and conventional liners had identical inner-head pull-out resistance (901N vs. 909N), jump distance (9.4 mm mode-A, 11.7 mm mode-B) and impingement-free range of motion (47° mode-A, 29° mode-B). Conclusion. This study showed that distal portions of conventional DM liners can impinge against iliopsoas and hip capsule in low flexion leading to functional impediment of liner motion. Additionally, reducing the liner profile below the equator led to significant reduction in soft-tissue impingement/tenting without affecting mechanical performance. Thus, a contoured dual mobility liner design may reduce the risk of anterior hip pain and intra-prosthetic dislocation resulting from soft-tissue impingement and liner entrapment. To view tables/figures, please contact authors directly

Purpose of study:. A retrospective clinical and telephonic survey of AMIS patients. Minimally Invasive Anterior Hip Replacements have been performed according to the AMIS technique in two centres in South Africa on a regular basis since 2 February 2007. We report on the first 335 cases that were done from February 2007 till October 2009 in these two centers, by two surgeons. Description of methods:. The data reported from these patients was collected from clinical notes, hospital records and telephonic questionnaires. Of the 335 cases that were performed data could be collected from 283 patients. Patients lost to follow up were 16 deceased, 24 could not be reached and 12 others had co-morbidities like Alzheimers, Total deafness and CVA. Summary of results:. The data collected includes: Patient demographics, diagnosis, co-morbidities. We also collected data of the surgical procedures including the duration of the procedure, prosthesis used, and hospital stay. We also collected data of the functional activities and time duration to achieving this. These activities include driving a car, shopping, domestic work, gardening and sport like hiking and golf. Complications reported include superficial wound infection 4, deep infections 1, dislocation 6, hematoma 8, impingement 1 and fractures 4. Total rate of revision was 2.47 %. Analysis of the causes of revision were; subsidence and dislocation 3, anterior acetabular impingement 1, proximal femoral loosening and persistent thigh pain 1, fractured ceramic liner 1, displaced acetabular component 1. Discussion:. The anterior approach for total hip replacement is a new method that preserves all the musculature around the hip joint with resultant benefits. This is a demanding technique that is reflected in the results. 80 % of the revisions were encountered in the first 50 cases