Arthroscopic Cam Resection Research Articles

Physical Therapy May Not Be Successful for Patients With Cam-Type Femoroacetabular Impingement Syndrome and May Result in Insufficient Hip Range of Motion When Femoral Anteversion Is Less Than 16° and α-Angle Is Greater Than 65°

To identify factors associated with insufficient range of motion (ROM) improvement after the posterior pelvic tilt change in cam-type femoroacetabular impingement syndrome. Preoperative computed tomography images from 71 consecutive patients with femoroacetabular impingement syndrome treated with arthroscopic cam resection were evaluated. Using a dynamic computer simulation program, 3-dimensional models with a 10° posterior pelvic tilt from the supine functional pelvic plane (baseline) were created by computed tomography models. Patients were divided into 2 groups: those who experienced >10° (effective group) and ≤10° (ineffective group) improvements in internal rotation at 90° flexion after a 10° posterior pelvic tilt. Demographic characteristics; preoperative range of internal rotation at 90° flexion; and radiographic parameters, including Tönnis grade, lateral center-edge angle, acetabular roof obliquity angle, central acetabular anteversion, cranial acetabular anteversion, femoral anteversion, and α angle, were compared in the 2 groups. Univariate and multivariable logistic regression analyses were performed to evaluate factors associated with insufficient ROM improvement following a 10° posterior pelvic tilt. The 71 patients included 58 men and 13 women, of mean age 41.4 ± 14.6 years. Posterior pelvic tilt was effective in 13 hips and ineffective in 58. Univariate analysis showed that preoperative range of internal rotation at 90°flexion, femoral anteversion, and α angle differed significantly in the 2 groups. Multivariable analysis showed that femoral anteversion <16° (odds ratio 7.4; 95% confidence interval 1.6-35; P= .012) and α angle >65° (odds ratio 6.7; 95% confidence interval 1.2-37; P= .027) were significant factors associated with insufficient ROM improvement after posterior pelvic tilt. Physical therapy may not be successful for patients with cam-type femoroacetabular impingement syndrome and may result in insufficient hip ROM when femoral anteversion is less than 16° and α-angle is greater than 65°. Patients with a prominent cam-type deformity and lower anterior femoral anteversion are at high risk of clinical failure following improvement in pelvic mobility by conservative treatment alone and are likely to benefit from surgery for cam deformity.

Effect of 3-Dimensional Versus Single-Plane Changes in Pelvic Dynamics on Range of Motion in Hips With Femoroacetabular Impingement: A Computer Simulation Analysis.

Background:Femoroacetabular impingement (FAI) is primarily caused by bony impingement between the acetabulum and femoral neck during hip motion. Increasing posterior pelvic tilt improves hip range of motion in patients with FAI.Purpose:To use computer simulation analysis to compare the effects of 3-dimensional (3D) changes in pelvic tilt (sagittal tilt [St], axial rotation, and coronal tilt) with changes in a single plane (St), with the aim of improving range of motion in patients with FAI.Study Design:Controlled laboratory study.Methods:We evaluated 43 patients with FAI treated by arthroscopic cam resection. A 3D simulation was used to construct the following pelvic models: a 5° and 10° increase posteriorly in St (St5° and St10°) and a combined 5° change in St, axial rotation, and coronal tilt (Complex5°) from the baseline of the anterior pelvic plane. Improvements in maximum internal rotation (MIR) at 45°, 70°, and 90° of hip flexion and improvements in maximum flexion with no internal rotation were compared among the St5°, St10°, and Complex5° models. The pelvic models of each single-plane change of 5° and 10° were evaluated in the same simulation.Results:At 90° and 70°, there was a significant difference between the Complex5° and St10° models with respect to improvement in MIR (P = .004 at 90° of flexion; P = .017 at 70° of flexion). There was no significant difference in MIR at 45° of flexion (P = .71) or in maximum flexion (P = .42).Conclusion:At 70° and 90° of hip flexion, a combined change in 3D pelvic alignment of 5° (ie, St, axial rotation, and coronal tilt) was more effective in improving hip MIR than a 10° change in St only.Clinical Relevance:Effective physical therapy for FAI should address pelvic motion in all 3 planes rather than in a single plane.

Incidence of Heterotopic Ossification with NSAID Prophylaxis Is Low After Open and Arthroscopic Hip Preservation Surgery

PurposeWe evaluate the incidence of heterotopic ossification (HO) development with nonsteroidal anti-inflammatory drug (NSAID) prophylaxis in patients after open and arthroscopic hip preservation surgery.MethodsA retrospective review identified patients who underwent hip preservation surgery at a single institution within the past 3 years. Patients who underwent hip arthroscopy with or without periacetabular osteotomy (PAO) or femoral osteotomy (FO) were included. Those who did not receive 3-month postoperative radiographs were excluded. The incidence and Brooker classification (BC) of HO in patients taking Naproxen or another NSAID (meloxicam, celecoxib, indomethacin, or aspirin alone) was assessed using AP radiographs available from 3-, 6-, and 12-month follow-up appointments. Univariate analysis was conducted to compare numerical means and categorical data (significance level P = .05).ResultsA total of 328 hips (284 patients) were included. All patients received hip arthroscopy, while 71 patients (21.6%) received concurrent periacetabular osteotomy (PAO; n = 65) or femoral osteotomy (FO; n = 6). Overall, 276 hips (84.4%) received Naproxen for HO prophylaxis. In total, 5 of 328 hips (1.5%) developed HO (4, BC I; 1, BC III). The rate of HO development was significantly higher in males versus females (4 of 121 (3.31%) vs 1 of 207 (.48%), P = .0441). All 5 patients received arthroscopic cam resection and labral repair, and 1 patient also received PAO. Three patients in the Naproxen group (.91%) developed HO, which was not statistically different from those taking a different NSAID (.61%, P = .1797).ConclusionThe incidence of HO development was low with NSAID prophylaxis after hip preservation surgery.

Effect of Decreasing the Anterior Pelvic Tilt on Range of Motion in Femoroacetabular Impingement: A Computer-Simulation Study.

Background:The influence of pelvic tilt mobility, which can be reproduced in computer-simulation models, is an important subject to be addressed in the understanding of femoroacetabular impingement (FAI) pathophysiology.Purpose:To use computer-simulation models of FAI cases to evaluate the optimum improvement in hip range of motion (ROM) achieved by decreasing the anterior pelvic tilt and compare the results with the improvement in ROM achieved after cam resection surgery.Study Design:Controlled laboratory study.Methods:The pre- and postoperative computed tomography (CT) images from 28 patients with FAI treated with arthroscopic cam resection were evaluated. Using a dynamic computer-simulation program, 3-dimensional models with a 5° and a 10° decrease in anterior pelvic tilt from the supine functional pelvic plane (baseline) were created from the preoperative CT scans. Similar models were constructed for hips before (at baseline) and after cam resection. Improvements from baseline in maximum internal rotation at 45°, 70°, and 90° of flexion were assessed for the 5° change in pelvic tilt, 10° change in pelvic tilt, and cam resection models, and the results were compared for all conditions.Results:The combination of a 10° change in pelvic tilt and cam resection showed the largest ROM improvement from baseline (P < .001). Improvement in internal rotation in the cam resection model was significantly higher compared with the 5° pelvic tilt change model (P < .001), while there was no significant difference between the cam resection model and the 10° pelvic tilt change model.Conclusion:Decreasing anterior pelvic tilt by 10° in the preoperative computer simulation model resulted in an equivalent effect to cam resection, while a 5° change in pelvic tilt was inferior to cam resection in terms of ROM improvement.Clinical Relevance:Enough of a decrease in anterior pelvic tilt may contribute to ROM improvement that is as effective as that of cam resection surgery.

Midterm Follow-Up and Assessment of Cartilage Thickness by Arthro-Magnetic Resonance Imaging After Arthroscopic Cam Resection, Labral Repair, and Rim Trimming Without Labral Detachment

To evaluate the clinical and radiological outcome, sum of acetabular and femoral cartilage thickness, and rate of failure in the midterm after arthroscopic treatment of femoroacetabular impingement (FAI) syndrome with femoral osteoplasty, labral repair, and rim trimming without labral detachment. This retrospective case series included patients with FAI syndrome who had undergone hip arthroscopy from January 2009 to December 2010 by a single surgeon, with a minimum follow-up of 55 months. Data from patients who had undergone arthroscopic hip procedures with labral repair, rim trimming, and femoral osteoplasty were analyzed pre- and postoperatively. Clinical outcome (nonarthritic hip score [NAHS], Short Form 36 [SF-36]), range of motion, progression of osteoarthritis (Tönnis grade), radiological parameters (α angle, lateral center-edge angle [LCEA], Tönnis angle), femoral and acetabular cartilage thickness (using magnetic resonance imaging [MRI]), and intraoperative findings were evaluated. Of 148 hip arthroscopies performed, 97 included rim trimming, labral refixation, and femoral osteoplasty. Ten cases were lost to follow-up, leaving 87 hips. Arthroscopic revision was performed on 4 hips and total hip replacement on 4 hips, and 1 hip underwent both arthroscopic revision and total hip replacement. Excluding these 9 cases of revision, for which follow-up was not possible (retrospective study), the remaining 78 hips were followed up for a minimum of 55 months (77 ± 11.4, mean ± SD; range 55 to 124). Mean NAHS (65 to 88, P < .001), SF-36 physical subscale (65 to 85, P < .001), and the numerical pain rating scale (NRS) (5 to 1, P < .001) improved significantly. Outcome scores of minimal clinical importance (NAHS) were achieved in 67.6% of the patients. Mean range of movement improved significantly in flexion (109 to 122, P< .001) and internal rotation (10 to 22.7, P < .001). NAHS was positively associated with flexion of the hip postoperatively (r= 0.307, P= .011). In 16 cases, microfracture was performed (15 acetabular and 1 femoral). Preoperative α angles (anteroposterior and modified Dunn) were significantly higher in this cohort (P < .001, 95% confidence interval 8.9 to 25.2, P= .001). Twenty hips (28 %) progressed to worse Tönnis grades. Initial Tönnis grades were grade 0, 38; grade 1, 48; grade 2, 8. Pre- or postoperative Tönnis grades did not show any correlation with pre- or postoperative NAHS and NRS. MRI measurements at the latest follow-up (69 patients) of the femoral and acetabular cartilage thickness did not reveal any significant reduction at the 12 o'clock position. Arthroscopic cam resection, rim trimming, and labral repair without detachment of the labrum provides good or excellent outcome in 77.1% of hips based on NAHS in the midterm. Higher range of motion in flexion is associated with higher NAHS postoperatively. Arthroscopic cam resection, rim trimming and labral repair without detachment of the labrum is a successful method for the treatment of FAI syndrome in the midterm. IV, retrospective case series.

Accurate Arthroscopic Cam Resection Normalizes Contact Stresses in Patients With Femoroacetabular Impingement

Background: Femoroacetabular impingement (FAI) is increasingly recognized as a cause of hip pain in young adults. The condition leads to chondrolabral separation and chondral delamination and eventually predisposes to osteoarthritis of the hip. FAI that inflicts cartilage damage has been observed in hips with abnormal morphological characteristics and is related to a long-term evolution toward osteoarthritis. Arthroscopic surgery, which allows for correction of morphological characteristics and restores impingement-free motions, is the current standard of treatment. Hypothesis: Arthroscopic cam resection can restore the normal mechanical environment of the hip joint in cam-type FAI. Study Design: Descriptive laboratory study. Methods: Patient-specific discrete element models from 10 patients with cam-type FAI (all male; age, 18-40 years) were defined based on preoperative computed tomography scans and postoperative magnetic resonance imaging (MRI) scans. Complete cam resection postoperatively on MRI was confirmed with alpha angles <55°. The preoperative and postoperative peak contact stress findings during impingement testing were compared against a matched control group. Results: Peak contact stress was significantly elevated in patients with cam-type FAI during impingement testing, with increasing amounts of internal hip rotation (26.6 ± 11.64 MPa in cam patients preoperatively, 12.1 ± 4.62 MPa in those same patients postoperatively, and 11.4 ± 1.72 MPa in the virtual control group during impingement testing at 20° of internal hip rotation; P < .01). This effect was normalized after arthroscopic cam resection and loading patterns matched those of the control group. Conclusion: Accurate arthroscopic cam resection restored the normal peak joint contact stresses in the hip joint. This highlights the importance of early and complete cam resections in the face of a positive diagnosis of cam-type FAI. Clinical Relevance: Treatment of cam-type FAI effectively normalizes hip joint contact mechanics.

Does acetabular coverage influence the clinical outcome of arthroscopically treated cam-type femoroacetabular impingement (FAI)?

What represents clinically significant acetabular undercoverage in patients with symptomatic cam-type femoroacetabular impingement (FAI) remains controversial. The aim of this study was to examine the influence of the degree of acetabular coverage on the functional outcome of patients treated arthroscopically for cam-type FAI. Between October 2005 and June 2016, 88 patients (97 hips) underwent arthroscopic cam resection and concomitant labral debridement and/or refixation. There were 57 male and 31 female patients with a mean age of 31.0 years (17.0 to 48.5) and a mean body mass index (BMI) of 25.4 kg/m2 (18.9 to 34.9). We used the Hip2Norm, an object-oriented-platform program, to perform 3D analysis of hip joint morphology using 2D anteroposterior pelvic radiographs. The lateral centre-edge angle, anterior coverage, posterior coverage, total femoral coverage, and alpha angle were measured for each hip. The presence or absence of crossover sign, posterior wall sign, and the value of acetabular retroversion index were identified automatically by Hip2Norm. Patient-reported outcome scores were collected preoperatively and at final follow-up with the Hip Disability and Osteoarthritis Outcome Score (HOOS). At a mean follow-up of 2.7 years (1 to 8, sd 1.6), all functional outcome scores significantly improved overall. Radiographically, only preoperative anterior coverage had a negative correlation with the improvement of the HOOS symptom subscale (r = -0.28, p = 0.005). No significant difference in relative change in HOOS subscale scores was found according to the presence or absence of radiographic signs of retroversion. Our study demonstrated the anterior coverage as an important modifier influencing the functional outcome of arthroscopically treated cam-type FAI. Cite this article: Bone Joint J 2018;100-B:831-8.

Mechanical Strength of the Proximal Femur After Arthroscopic Osteochondroplasty for Femoroacetabular Impingement: Finite Element Analysis and 3-Dimensional Image Analysis

To examine the influence of femoral neck resection on the mechanical strength of the proximal femur in actual surgery. Eighteen subjects who received arthroscopic cam resection for cam-type femoroacetabular impingement (FAI) were included. Finite element analyses (FEAs) were performed to calculate changes in simulative fracture load between pre- and postoperative femur models. The finite element femur models were constructed from computed tomographic images; thus, the models represented the shape of the original femur, including the bone resection site. Three-dimensional image analysis of the bone resection site was performed to identify morphometric factors that affect strength in the postoperative femur model. Four oblique sagittal planes running perpendicular to the femoral neck axis were used as reference planes to measure the bone resection site. At the transcervical reference plane, both the bone resection depth and the cross-sectional area at the resection site correlated strongly with postoperative changes in the simulated fracture load (R2= 0.6, P= .0001). However, only resection depth was significantly correlated with the simulated fracture load at the reference plane for the head-neck junction. The resected bone volume did not correlate with the postoperative changes in the simulated fracture load. The results of our FEA suggest that the bone resection depth measured at the head-neck junction and transcervical reference plane correlates with fracture risk after osteochondroplasty. By contrast, bone resection at more proximal areas did not have a significant effect on the postoperative femur model strength in our FEA. The total volume of resected bone was also not significantly correlated with postoperative changes in femur model strength. This biomechanical study using FEA suggest that there is a risk of femoral neck fracture after arthroscopic cam resection, particularly when the resected lesion is located distally.

Ultrasonography can quantify the extent of osteochondroplasty after treatment of Cam-type femoroacetabular impingement

Surgical resection of femoroacetabular Cam impingement (cam-FAI) is now a generally accepted treatment, producing adequate hip score increases. Insufficient resection at the head-neck junction is the main reason for revision. The anterolateral region of the head-neck junction is visualized only suboptimally by radiography, which can be inadequate for monitoring resection results postoperatively. Our aim was to investigate the extent of Cam resection by ultrasonography (US) and determine if there is any correlation with clinical outcome. Altogether, 40 consecutive patients (mean age 39 years) were enrolled in this prospective study following arthroscopic Cam resection. All patients underwent standardized US examination in the ventral longitudinal section at 20° external rotation, neutral position, and 20° internal rotation the day before arthroscopy and two days afterward. Alpha angle, anterior offset, offset ratio, and anterior femoral distance were measured on sonograms. Hip Disability and Osteoarthritis Outcome Score (HOOS) and Western Ontario and McMaster University Index of Osteoarthritis (WOMAC) were conducted the day before surgery and 6 weeks postoperatively (at the earliest). Alpha angle was significantly smaller on postoperative US in all hip joint positions. At 20° internal rotation, the alpha angle decreased from 65.6 to 36.9° (p < 0.0001). All but two (5%) patients had alpha angles <50°. Anterior offset increased significantly on US in neutral position and at 20° internal rotation. HOOS and WOMAC increased significantly. No correlation was found between measurements for Cam-FAI and the scores. US may be a useful tool for monitoring Cam-FAI resection results postoperatively.

Hip Arthroscopy for Femoroacetabular Impingement: Results of 118 Consecutive Cases in a District General Hospital

Femoroacetabular impingement (FAI) is an increasingly recognised cause of hip symptoms in the young active adult and can lead to labral tears and chondral damage. FAI can be treated with open surgery or arthroscopically: aiming to stabilise labral tears and remove bony impingement. We report the results of a single surgeon series of arthroscopic labral debridement and cam resection in 118 consecutive cases during a two-year period, with a minimum follow-up of one year. Quantitative assessment was undertaken using the Non-Arthritic Hip Score (NAHS) calculated preoperatively and at two, four and 12 months postoperatively. Mean NAHS in all patient groups at two and four months, and at one year showed improvement (p<0.05). These results compare favourably with previous patients treated with open osteochondroplasty by the same surgeon, as well as with the published results from other larger centres. The faster improvement and the shorter hospital stay and lower morbidity make arthroscopic surgery for FAI a favourable option, and a feasible treatment modality in the non-specialist setting.

Arthroscopic Appearance and Treatment of Impingement Cysts at Femoral Head-Neck Junction

To study the arthroscopic appearance and treatment of impingement cysts and to propose their potential intraoperative value for correct femoral osteochondroplasty in femoroacetabular impingement (FAI). We performed a single-surgeon, retrospective study of 152 consecutive hip arthroscopies in 141 patients treated for FAI due to cam, localized pincer, or mixed FAI. Radiographic (conventional radiographs and magnetic resonance arthrography) cyst sizes and locations as well as the arthroscopic appearance were recorded. On the preoperative radiographs, impingement cysts were radiographically visible in 18% of treated FAI patients (26 of 141); 15% of these patients (4 of 26) had more than 1 cyst. Age was the only independent predictor of cysts, with a 7-year shift to a mean age of 42 years. The majority of cysts were located in the anterosuperior quadrant of the femoral head-neck junction (93%), the mean diameter of cysts was 7.0 mm, with a range from 3.7 to 15.1 mm. During surgery, only a few were arthroscopically identifiable, with a pit-like (3 of 26) or crater-like appearance (3 of 26) (i.e., surface alterations) for the larger cysts. The majority of cysts (20 of 26) became evident, however, after unroofing of the area of cam FAI. Cysts were associated with labral (25 of 26) and/or chondral lesions (23 of 26). Small cysts were completely removed during femoral osteochondroplasty, whereas larger cysts were only resected until impingement-free range of motion was reached. No neck fractures occurred in this series. Impingement cysts were present on 1 in 6 radiographs in patients undergoing hip arthroscopy for FAI and were found most commonly in older patients. The cysts predictably occur within the epicenter of the femoral-induced impingement. Whereas surface alterations are rare (6 of 26), the content and base of the unroofed cyst are consistent. Most cysts are completely excised as part of the femoral impingement correction and may be used as a confirmation that arthroscopic cam resection has been performed at the correct site. Level IV, therapeutic case series.