Purpose: The surgical correction of FAI deformity is a well accepted treatment in patients presenting with hip pain with associated labral-chondral damage. The anterior approach with assisted hip arthroscopy provides access to the anterior head-neck junction with potentially quicker recovery for patients. The purpose of this study is to present the safety and efficacy of this approach in performing impingement surgery.

Method: Forty-eight Hueter procedures were performed in 45 patients (13 males and 32 females). Mean age was 42.09 years (range, 21–65 years), and mean BMI was 24.31(range, 21–33). The scope was performed first to deal with intra-articular damage. All patients were diagnosed with CAM type FAI with labral pathology based on MRI arthrogram with an alpha angle > 50.5 degrees.

Results: At a mean follow-up of 21.8 months (range 12–30 months), Harris Hip scores improved from 64.66 (range, 42.0–93.0) to 79.97 (range, 47.0–96.0). There were 5 re-operations at a mean time of 15.2 months (range, 4–22). One had a repeat hip scope for intra-articular adhesions, and another for recurrent traumatic tear of the labrum. Three cases with residual hip dysplasia had corrective surgery with a peri-acetabular osteotomy at an average of 16.67 months (range, 15–18 months).

Conclusion: Overall, we have found this to be a reliable, safe and reproducible approach to the treatment of FAI. This is a day care procedure as compared to the classic open procedure. Uncorrected hip dysplasia in the presence of a CAM deformity is a risk factor for early failure.

Purpose: LFCN neuropraxia is a known complication of the anterior approach to the hip joint. The objective of this study was to define the incidence, functional impact and natural history of this neuropraxia in the anterior approach after both hip resurfacing (HR) and primary total hip arthroplasty (THA).

Method: Between September 2006 and January 2008, 132 consecutive patients underwent a direct anterior hip approach (DAA) (55 THR; 77 HR). Sixty-two patients were female and 70 were male; the mean age was 55.54 (range, 29.9 to 88.7). Self reported questionnaires for sensory deficits of LFCN, a neuropathic pain score (DN4) as well as SF-12, UCLA and WOMAC scores were completed. A subset of 60 patients (30 THA, 30 resurfacing) was evaluated at two time intervals (6 and 12 months).

Results: One hundred and seven patients (81%) reported LFCN neuropraxia, with a mean severity score of 2.32/10 (SD, 2.11); mean DN4 score of 2.42/10 (SD, 2.37). Hip resurfacing had a higher incidence of neuro-praxia compared to THA: 91% versus 67% (p=0.02), respectively. No functional limitations were reported on SF-12, WOMAC or UCLA scores. Of the subset of 60 patients, 53 (88.3%) reported neuropraxia at the six month follow-up interval with only three (5.7%) having complete resolution at 12 months. Patients who reported neuropraxia at both testing intervals did report an improvement in DN4 scores: 3.6 versus 2.5 at 6 and 12 months, respectively (p=0.02).

Conclusion: Although LFCN neuropraxia is a frequent complication after DAA total hip arthroplasty, it does not lead to any functional limitations. A decrease in symptoms does occur over time, with only a small number of patients reporting complete resolution.

Purpose: Femoroacetabular impingement (FAI) is recognized as a pathomechanical process that leads to hip osteoarthritis (OA). Past research has been focused on treatments for FAI; however, few studies have been done to link FAI with the progression of OA. It is hypothesized that elevated mechanical stimuli could provoke bone remodeling in the subchondral bone and articulating surfaces due to cam FAI (aspherical head-neck deformity), which would accelerate the progression of OA. Using finite element analysis (FEA), the aim is to compare healthy hips to hips with cam FAI – investigating the mechanical stimuli effect of FAI towards OA.

Method: Net joint reaction forces were obtained from joint kinematics, kinetics, and by inverse dynamics calculation for a dynamic squat motion of a control subject and a cam FAI patient (both males with comparable age, BMI, and femur lengths). CT scans were acquired from both subjects. Data slices were compiled using 3D-DOCTOR (Able Software Corp, MA) to form a 3D model with slice thickness calibrated at 1.25mm in the superior-inferior axis. ANSYS (ANSYS, PA) software was used for FEA. The femur models were given quadrilateral shell elements and modeled as linear elastic orthotropic materials. The ground reaction forces were applied to the femur models, simulating dynamic loads, using boundary conditions specific to hip loading. Von Mises stresses were determined to examine stress concentrations and adverse loading conditions. Strain energy distributions were determined to examine the effect of stimuli on the initiation and rate of bone remodeling.

Results: At the maximum squat-depth, the FEA results demonstrated that the net forces acting on the FAI hip produced high mechanical stimuli regions around the head and neck. The highest stress concentration (590 MPa) was located at the anterosuperior head-neck junction, where cam FAI is most prominent. For the control hip, stresses were significantly lower (maximum of 151 MPa) and dissipated around the head. For both the FAI and the control hip, the maximum strain energy concentrations were seen at the superior portion of the head (4.725 kJ vs. 2.192 kJ for FAI vs. control hip respectively).

Conclusion: The increase in mechanical stimuli can be due to the loading configurations as well as to the abnormal geometry of the cam deformity. Assuming that the strain energy density (SED) and its rate is linearly proportional to the rate of bone turnover, based on a recent semi-mechanistic bone remodeling theory, a higher rate of bone turnover is expected in the FAI than in a normal hip. Depending on the level and rate of SED, the rate of bone remodeling will vary in order to provide a new homeostatic configuration. The next-step analysis, examining the mechanical stimuli in the acetabulum and its cartilage, is currently in progress. This would provide useful information about the possible locations of OA initiation and establish a link between FAI with cartilage degeneration.

Purpose: It is thought that the anterior approach better restores gait mechanics after total hip arthroplasty (THA) being a pure intermuscular/internervous approach. The purpose of this study was to compare three-dimensional (3-D) kinematics and kinetics of THA patients that had an anterior (ANT) vs. a lateral (LAT) approach. It is hypothesized that the ANT group will exhibit fewer differences than the LAT group when compared to a control group (CON).

Method: Fifty-four participants were divided into three groups of 18: ANT (12 women, 6 men; age: 60.9 ± 6.2 yr; BMI: 28.8 ± 4.9 kg/m2), LAT (10 women, 8 men; age: 65.2 ± 6.3 yr; BMI: 27.5 ± 5.1 kg/m2) and CON (9 women, 9 men; age: 63.9 ± 4.4 yr; BMI: 25.4 ± 3.2 kg/ m2). All THA patients had primary unilateral THA due to osteoarthritis and had no other lower-limb pathology. They were evaluated five to 17 months after surgery. 3-D kinematics and kinetics were obtained using a nine-camera motion analysis system and a force platform placed on the first step of a staircase. Each participant performed three trials of stair ascending. A series of one-way ANOVAs were used to compare peak angles, range of motion (ROM), peak resultant joint forces as well as moments and powers of the hip, knee and ankle joints in all three planes.

Results: Most differences occurred during transitions between double- to single-legged stance. Both LAT and ANT groups ascended the staircase with a more abducted hip than the CON group, resulting in reduced hip abduction moment. This could be the result of the implant’s position and its potential abductor lever arm reduction. Both groups also showed reduced peak internal rotation moments. These results have previously been found in THA patients who have been operated through lateral and posterior approaches, and are thought to be caused by hip abductor muscle damage inherent to the surgical approach. However, only the LAT group had lower compression forces at the hip, knee and ankle joints compared to the CON group. This indicates that LAT group uses a strategy that reduces the loading on the operated leg, which may be due to the detachment of the anterior third of the gluteus medius. It could be speculated that the muscle sparing aspect of ANT approach allows patients to load adequately their operated leg, even if their frontal plane kinematics and kinetics are altered.

Conclusion: Some studies have failed to find differences with the anterior approach. However, they have only looked at spatiotemporal gait parameters. 3-D kinematics and kinetics can provide a more detailed assessment of function and detect more subtle differences. In this study, 3-D biomechanical analysis has detected differences in THA patients operated through different surgical approaches during stair ascent. The data obtained showed similar frontal plane kinematics for both groups, but different lower-limb compression forces. This study supports the use of the anterior approach for better restoration of function after total hip arthroplasty.

Purpose: Iatrogenic acetabular retroversion is a known complication after pelvic osteotomy leading to persistent hip pain and increasing risk of subsequent osteoarthritis. The purpose of this study is to document the incidence of acetabular retroversion and signs of impingement in patients who have had a Salter pelvic osteotomy in childhood.

Method: Twenty eight patients (32 hips) had a Salter Osteotomy between 1980 and 1999, 16 were lost to follow-up. Of the 12 studied, eight had a diagnosis of DDH and four had Legg Calve Perthes. Clinical assessment for the presence of the impingement sign, range of motion and leg length discrepancy was done as well as functional scores. AP pelvic radiographs were taken to assess acetabular retroversion (cross-over or ischial sign), osteoarthritis using the Tonnis grade, center-edge and Tonnis angles.

Results: The mean age of the sample was 17.25 years (SD=7.27) with a mean follow-up of 10.56 years (SD=6.27). Impingement sign was positive in seven patients (58.3%). Nine out of the 12 had acetabular retroversion. Nine had Tonnis grade 1, two Tonnis grade 2, and one had a Tonnis grade 3. Mean center edge and Tonnis angles were 26° (SD=16.43) and 9.09° (SD=6.49), respectively. There was no correlation between presence of acetabular retroversion with Tonnis grade (p=.700), hip pain (p=.317) or impingement sign (p=.621).

Conclusion: Retroversion is highly prevalent (69.2%) in patients who underwent a Salter pelvic osteotomy for a childhood hip disease. Although acetabular retroversion is a known cause of impingement in adulthood, our patient cohort was too small to detect a significant impact on the functional scores.

Purpose: We aimed to measure the early migration pattern of a titanium alloy, tapered, plasma and hydroxyapatite coated femoral stem and any factors associated with subsidence.

Method: Between January 2005–June 2007, 387 Accolade cementless femoral stems (Stryker, Allendale NJ) were implanted at our institution. Seventy-seven had a minimum of two years post operative follow up and a complete set of pre and postoperative radiographs for analysis. Our group inlcuded 45 females with a mean age of 71.4 years, and 32 males with a mean age of 68.5 years. The primary diagnosis was degenerative osteoarthritis in 71 patients, avascular necrosis in two, and post fracture in four patients. The average BMI was 27.1. We measured the canal index to assess bone quality and the canal calcar index to assess the proximal femoral morphology. Immediate postoperative radiographs were assessed for canal fill of the prosthesis and implantation varus/valgus angles. The EBRA-FCA software was used to obtain migration curves for each stem. Best fit curve of subsidence over time was calculated and the data was analysed using a Kaplan Meier survivorship with 1.5 mm of subsidence as an endpoint. We then performed a multivariate and univariate regression analysis for predictors of subsidence.

Results: The mean follow up was 29.3months (24–48). The mean canal index was 0.55 (0.36–0.68) with a mean canal calcar index of 0.54 (0.39–0.79). The average canal fill index at the midpoint of the stem was 80 in 40 stems. A total of 414 radiographs were analysed for the EBRA measurements. Of these 21 (5%) were discarded by the software as they did not meet the criteria for comparability. This led to the exclusion of seven patients, leaving the final study group of 77. All remaining patients had a minimum of four radiographs with an average of 4.6 for analysis. The average subsidence at 24 months was 2 mm and this had risen to 2.4 mm by 36 months postoperatively. When analysed using a Kaplan Meier curve using 1.5 mm as an end point we found a survivorship of 63.4% (52.3–74.5) at 24 months and this had worsened to 41.6% (26.6–56.5) by 36 months. Multivariate and univariate regression analysis of measured variables did not reveal any significant hazard for any factor other than the larger stem sizes doing worse.

Conclusion: Although several cementless tapered stem designs have had an excellent track record, our migration analysis of the Accolade stem is somewhat concerning. Thirty three percent of stems had reached the 1.5 mm subsidence point by two years. This is of concern as work has previously shown this to predict failure of stems with aseptic loosening at ten years with an accuracy of 79%. If these stems go on to fail at the predicted rate this would represent an unacceptably high level of failure. Our data raises serious concerns about the overall clinical performance of this stem design due to poor initial stability and integration.

Obtaining fixation in DDH with Surface arthroplasty (SA) with a two part polyethylene (PE ) socket was technically challenging. Although dislocation was rare there was a high loosening rate secondary to polyethylene wear. The purpose of this study was to evaluate the results of Conserve Plus metal-on-metal SA in Crowe class I and II Developmental Dysplasia of the Hip patients.

54 patients (59 hips), 72% females, average age43.7 years (15 to 63.8) met these inclusion creteria with 2 years of follow-up minimum. Seven hips were Crowe type II and fifty-two were type I.

Harlan C. Amstutz, John Antoniades, Michel J. Le Duff, Paul E. Beaulé

The results of MMSA are much improved over those of prior generations of SA and socket fixation is stable even in Crowe type II with the porous coated acetabular components without adjuvant fixation despite incomplete acetabular coverage of the socket. The hips have-been stable even with important range of motion. Recent short term failure and radiolucencies have been eliminated by improved technique despite a high incidence of femoral cysts and reduced area of fixation.

The purpose of the present study was to identify risk factors for femoral loosening and neck fracture for Conserve+ metal-on-metal hybrid surface atrhroplasty.

The first 500 hips (of over 700 implanted by the senior author) in 436 patients were reviewed. Mean age was 48.6 with 74% of males patients.

16 hips were converted to THR secondary to aseptic failure on the femoral side (11 femoral component loosenings and 5 femoral neck fractures). 14 hips showed radiolucencies around the short metaphyseal stem at last follow-up. A retrieval analysis was performed and analyzed specimens compared with the intra operative photos of the prepared femoral head and the post-op X-rays. The cause of neck fractures is multifactorial. Risk factors include: uncovered reamed bone, leaving the component proud, notching the neck, impingement, osteopenia and cysts, and trauma. Avoidance of technical deficiencies and proper patient selection can eliminate neck fractures. Loosening is also multifactorial. Risk factors for loosening included: cysts > 1 cm, small femoral head size, female gender, early cases (before improved acrylic fixation including femoral suctioning measures were instituted) and reduced stem shaft angle.

Meticulous initial preparation of the femoral bone surfaces, drying with suctioning, and maximizing the fixation area are critical when the fixation area is small, especially with osteopenia and cystic degeneration. These techniques have dramatically diminished the incidence of loosening and radiolucencies. Cementing the femoral metaphyseal stem is a meaningful technical improvement towards the prevention of early femoral failure in patients with risk factors.

Purpose: A classification system for fractures is an important communication tool for surgeons allowing the development of management schemes as well as an estimation of the prognosis. The purpose of our work was to evaluate the inter- and intra-observer reproducibility of the Letournel classification system for acetabular fractures.

Material methods and results: Sixty-five x-rays (AP and Judet views) and computed tomography (CT) series were chosen at random from a data base containing 800 fractures. The distribution of the fracture types followed data in the literature. Three groups of observers were formed, each composed of three orthopaedic surgeons. Group 1 included surgeons who had studied with Letournel, group 2 surgeons specialised in acetabular fractures, and group 3 surgeons qualified for general traumatology surgery. The kappa coefficient was determined to assess agreement between observers. Each observer read the images twice without knowledge of the treatment. The observers first classed the fractures using the x-rays alone then with the x-rays in combination with the CT. Two sessions were organised, two months apart to avoid any possible memorisation. Reproducibility without then with CT for the first session were: group 1: 0.07 and 0.74; group 2: 0.71 and 0.69; group 3: 0.51 and 0.512. Results were similar in the second session. Intra-observer reproducibility without then with CT was: group 1: 0.80 and 0.83; group 2 0.80 and 0.80; group 3: 0.64 and 0.69. Among the six more experimented observers (groups 1 and 2), 100% agreement was found for 66% of the x-rays compared with 22% for the new observers.

Discussion and conclusion: The Letournel classification system using x-rays in combination or not with CT is reliable (kappa > 7) for properly trained surgeons with regular experience in treating acetabular fractures. The value of the CT in the assessment of acetabular fractures is well established for identifying detached elements and joint crush. Conversely, CT does not appear to be essential to class ace-tabular fractures. The Letournel classification can be used as a reliable tool for the description of acetabular fractures and taught to surgeons desiring to undertake regular treatment of these fractures.

Purpose: Diverse extended approaches have been described for the treatment of complex acetabular fractues. Little data is however available concerning the results, morbidity, and complications of acetabular fractures treated with this approach. The purpose of this work was to assess outcome in procedures performed by a single operator using the extended iliofemoral approach as described by Letournel for the treatment of acetabular fractures.

Material and methods: The database of the senior author included 833 acetabular fractures, 156 of which were operated via the extended iliofemoral approach in 109 patients who had a minimal two years follow-up. The series included 69 women and 40 men, mean age 34 years (11–93). Fracture type was: BC 64; TR+PW 15; T 12; ACH: 3; PW: 2; AC: 2. Delay before surgery was less than 21 days for 76 patients, between 21 days and three months for 22 and greater than three months for 11. There was a femoral head injury in 21% of the cases and 6% had had an earlier operation.

Results: At mean follow-up of 5.4 years (2–12), all fractures had healed. Reduction was anatomic in 69% of the cases, imperfect in 13ù and fair (interfragment gap > 3 mm) in 18%. The mean Postel Merle d’Aubigné score was 15 (5–18) with 63% excellent or good results. Complications were observed in 9% of the cases: seven infections, two serous discharges, and one necrosis of the scar borders. Ectopic ossifications were noted in 56% of the patients, 16% required surgical resection. Total arthroplasty was performed for 7% of the patients, arthrodesis for 4% and haematoma evacuation for 8%. The arthroplasty was revised two years after recurrent dislocation in one patient.

Discussion: This work allows us to conclude that the extended iliofemoral approach is safe and effective for the treatment of complex acetabular fractures. The percentage of excellent and good results is closely related to the quality of the reduction, and can be considered satisfactory known that the extended iliofemoral approach is used for more complex fractures less susceptible of healing. We recommend this approach for experimented operators well trained in the use of the iliofemoral approach.