The New Bern Chondrolabral Classification Is Reliable and Reproducible.

BACKGROUND: Several classification systems have been used to describe early lesions of hip cartilage and the acetabular labrum in young adults with hip pain. Some of them were introduced before the concept of femoroacetabular impingement was proposed. Others were developed for other joints (such as the patellofemoral joint). However, these often demonstrate inadequate reliability, and they do not characterize all possible lesions. Therefore, we developed a novel classification system. QUESTION/PURPOSE: We asked: What is the (1) intraobserver reliability, (2) interobserver reproducibility, and (3) percentage of nonclassifiable lesions of the new classification system for damage to the hip cartilage and labrum compared with six established classification systems for chondral lesions (Beck et al. [4], Konan et al. [10], Outerbridge et al. [14]) and labral lesions (Beck et al. [3], Lage et al. [12], Peters and Erickson [15])? METHODS: We performed a validation study of a new classification system of early chondrolabral degeneration lesions based on intraoperative video documentation taken during surgical hip dislocations for joint-preserving surgery in 57 hips (56 patients) performed by one surgeon with standard video documentation of intraarticular lesions. The exclusion criteria were low-quality videos, inadequate exposure angles, traumatic lesions, and incomplete radiographic documentation. This left 42 hips (41 patients) for the blinded and randomized analysis of six raters, including those with cam-pincer-type femoroacetabular impingement (FAI) (19 hips in 18 patients), isolated cam-type FAI (10 hips), extraarticular FAI due to femoral anteversion (seven hips), isolated pincer-type FAI (two hips), focal avascular necrosis (two hips), localized pigmented villonodular synovitis (one hip), and acetabular dysplasia as a sequelae of Perthes disease (one hip). The raters had various degrees of experience in hip surgery: Three were board-certified orthopaedic fellows and three were orthopaedic residents, in whom we chose to prove the general usability of the classification systems in less experienced readers. Every rater was given the original publication of all existing classification systems and a visual guide of the new Bern classification system. Every rater classified the lesions according the existing classifications (cartilage: Beck et al. [4], Konan et al. [10], and Outerbridge et al. [14]; labrum: Beck et al. [3], Peters and Erickson [15], and Lage et al. [12]) and our new Bern chondrolabral classification system. The intraclass correlation coefficient with 95% confidence interval was used to assess the intraobserver reliability and interobserver reproducibility. The percentage of nonclassifiable lesions was calculated as an absolute number and percentage. RESULTS: The intraobserver intercorrelation coefficients (ICCs) for cartilage lesions were as follows: the Bern classification system (0.68 [95% CI 0.61 to 0.70]), Beck (0.44 [95% CI 0.34 to 0.54]), Konan (0.39 [95% CI 0.29 to 0.49]), and the Outerbridge classification (0.57 [95% CI 0.48 to 0.65]). For labral lesions, the ICCs were as follows: the Bern classification (0.70 [95% CI 0.63 to 0.76]), Peters (0.42 [95% CI 0.31 to 0.51]), Lage (0.26 [95% CI 0.15 to 0.38]), and Beck (0.59 [95% CI 0.51 to 0.67]). The interobserver ICCs for cartilage were as follows: the Bern classification system (0.63 [95% CI 0.51 to 0.75), the Outerbridge (0.14 [95% CI 0.04 to 0.28]), Konan (0.58 [95% CI 0.40 to 0.76]), and Beck (0.52 [95% CI 0.39 to 0.66]). For labral lesions, the ICCs were as follows: the Bern classification (0.61 [95% CI 0.49 to 0.74]), Beck (0.31 [95% CI 0.19 to 0.46]), Peters (0.28 [95% CI 0.16 to 0.44]), and Lage (0.20 [95% CI 0.09 to 0.35]). The percentage of nonclassifiable cartilage lesions was 0% for the Bern, 0.04% for Beck, 17% for Konan, and 25% for the Outerbridge classification. The percentage of nonclassifiable labral lesions was 0% for Bern and Beck, 4% for Peters, and 25% for Lage. CONCLUSION: We have observed some shortcomings with currently used classification systems for hip pathology, and the new classification system we developed seems to have improved the intraobserver reliability compared with the Beck and Konan classifications in cartilage lesions and with the Peters and Lage classifications in labral lesions. The interrater reproducibility of the Bern classification seems to have improved in cartilage lesions compared with the Outerbridge classification and in labral lesions compared with the Beck, Peters, and Lage classifications. The Bern classification identified all present cartilage and labral lesions. It provides a solid clinical basis for accurate descriptions of early degenerative hip lesions independent of etiology, and it is reproducible enough to use in the reporting of clinical research. Further studies need to replicate our findings in the hands of nondevelopers and should focus on the prognostic value of this classification and its utility in guiding surgical indications. LEVEL OF EVIDENCE: Level II, diagnostic study.

Intracapsular cuneiform osteotomy compared with in-situ pinning for the management of slipped capital femoral epiphysis.

Intracapsular cuneiform osteotomy was initially introduced to restore the morphology of the proximal femur after slipped capital femoral epiphysis (SCFE). However, whether this procedure results in a higher risk of avascular necrosis (AVN) or lower incidence of cam deformity than in-situ pinning is unclear. The aim of this study was to compare the outcomes of intracapsular cuneiform osteotomy and in-situ pinning to treat SCFE in children. Twenty-three children who suffered from SCFE underwent either intracapsular cuneiform osteotomy (eight patients, eight hips) or in-situ pinning (15 patients, 18 hips) between 2006 and 2014. No patient was lost to follow-up at a mean of 4.5 years. In the osteotomy group, the Japanese Orthopedic Association's hip score system score increased from 50.5 (20-89) to 98.9 (95-100) and from 65.9 (48-90) to 99.0 (44-100) in the in-situ pinning group. On the basis of the slip angle, α angle, and epiphyseal-metaphyseal offset, intracapsular cuneiform osteotomy showed a significantly better result in restoring the morphology of the proximal femur than in-situ pinning (P<0.001). The incidences of AVN, chondrolysis, and lower limb discrepancy were similar between the two groups. On the basis of clinical outcomes, both intracapsular cuneiform osteotomy and in-situ pinning had acceptable abilities to treat SCFE. The incidence of AVN was not related to which technique was used. Osteotomy significantly restored the morphology of the proximal femur.

Nanofocusing of structured light for quadrupolar light-matter interactions.

The spatial structure of an electromagnetic field can determine the characteristics of light-matter interactions. A strong gradient of light in the near field can excite dipole-forbidden atomic transitions, e.g., electric quadrupole transitions, which are rarely observed under plane-wave far-field illumination. Structured light with a higher-order orbital angular momentum state may also modulate the selection rules in which an atom can absorb two quanta of angular momentum: one from the spin and another from the spatial structure of the beam. Here, we numerically demonstrate a strong focusing of structured light with a higher-order orbital angular momentum state in the near field. A quadrupole field was confined within a gap region of several tens of nanometres in a plasmonic tetramer structure. A plasmonic crystal surrounding the tetramer structure provides a robust antenna effect, where the incident structured light can be strongly coupled to the quadrupole field in the gap region with a larger alignment tolerance. The proposed system is expected to provide a platform for light-matter interactions with strong multipolar effects.

Long-term clinical and radiographic results of the cementless Spotorno stem in Japanese patients: A more than 15-year follow-up.

PURPOSE: Although previous studies have reported encouraging results of cementless Spotorno (CLS) stem, studies with more than 15 years of follow-up are rare. The objective of this study is to investigate the long-term results of CLS stem and the factors potentially influencing the outcomes. METHODS: The clinical and radiographic data of 79 hips (64 patients) were reviewed. Clinical outcome was determined using the Japanese Orthopedic Association's hip scoring system (JOA hip score). Survival rate was assessed by Kaplan-Meier survival analysis. The main end point for survival analysis was revision of stem. The correlations between patient demographics, radiographic factors, and stem survival rates were analyzed. RESULTS: At a mean follow-up period of 20.1 years, the mean JOA hip score at final follow-up was 84.7 points. Stem survival rate for all revisions was 97.5% at 20 years, and stem survival for aseptic loosening was 98.9%. Varus alignment had a significant negative influence on the survival of the femoral stem. CONCLUSION: This study demonstrates acceptable long-term clinical and radiographic results of the CLS stem in Japanese patients. Caution should be exercised to avoid varus stem alignment.

Clinical results of arthroscopic surgery in patients over 50 years of age-what viability does it have as a joint preservative surgery?

BACKGROUND: To identify whether hip arthroscopy is a suitable option for treating hip pain in elderly patients and investigate the clinical outcomes of hip arthroscopic surgery for labrum tear and/or osteoarthritis in patients over 50 years of age. METHODS: Between August 2009 and May 2014, a series of 23 patients (6 men and 17 women) with a mean age of 59 years underwent arthroscopy. We retrospectively examined the clinical records, radiographs, and outcome questionnaires from all patients. The mean follow-up period was 28 months. RESULTS: The mean Japan Orthopedic Association hip score after surgery improved by a statistically significant amount. Eight patients (34.8%) were noted to have a progression of osteoarthritis (OA) diagnosed by radiograph, and one underwent THA after 13 months following arthroscopic surgery. The patients in which OA progression was noted were identified as having radiographical OA preoperatively and acetabular cartilage damage in the arthroscopic findings. CONCLUSIONS: Arthroscopic surgery performed in selected patients over 50 years of age might be beneficial if classified as Tönnis grade 0 preoperatively and/or classified as Outerbridge grade II in the arthroscopic findings.

Early fracture of the modular neck of a MODULUS femoral stem.

We present the case of a 46-year-old woman who underwent revision surgery approximately 4 years after total hip arthroplasty because of a fracture of the modular neck of a MODULUS femoral stem. The fractured surfaces of the retrieved implant were inspected using optical and scanning electron microscopy. Three-dimensional finite element analysis was also performed to identify the stresses that might have caused the failure. We concluded that active, obese patients who are implanted with a high-offset, small-sized modular component could experience stress-induced fractures of the modular neck, with proper fixation and osseointegration of the distal stem, especially if residual bone or tissue is present on the inner surface of the neck that could contribute to micromovement and decreased proximal fixation.

Clinical Results and Prognostic Factors for Outcomes of Valgus Femoral Osteotomy Combined with Chiari Pelvic Osteotomy for Osteoarthritis of the Hip.

BACKGROUND: Surgeons have long debated whether advanced or end-stage osteoarthritis of the hip in young patients should be treated with total hip arthroplasty or osteotomy. We reviewed the intermediate-term clinical results of valgus femoral osteotomy combined with Chiari pelvic osteotomy (VCO) for advanced or end-stage osteoarthritis associated with severe acetabular dysplasia of the hip in young patients and analyzed prognostic factors related to conversion to total hip arthroplasty. METHODS: The study group included 54 hips in 50 patients (5 men and 45 women; average age at the time of surgery, 45.6 years). The minimum and average durations of follow-up were 10 and 17.6 years, respectively. The Japanese Orthopaedic Association hip score (JOA score) was used for clinical evaluation. The probability of survival of the VCO from the time of the operation until the end point of conversion to total hip arthroplasty was calculated with use of the Kaplan-Meier method. We defined prognostic factors of outcome (conversion to total hip arthroplasty) with the Cox proportional hazards model. RESULTS: The mean total JOA score increased from 53.0 points preoperatively to 77.1 points at 1 year postoperatively, 81.6 points at 5 years, and 76.8 points at 10 years. The survival rates were 83.3%, 59.7%, and 46.9% at 10, 15, and 20 years, respectively. On univariate and multivariate analyses, patients with a low degree of acetabular roof obliquity had better postoperative results. CONCLUSIONS: VCO is a surgical approach that preserves joint function in young patients with advanced or end-stage osteoarthritis associated with severe acetabular dysplasia of the hip. The postoperative prognosis of VCO was improved in patients with a low degree of acetabular roof obliquity. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Quadrupole lattice resonances in plasmonic crystal excited by cylindrical vector beams.

We report a scheme to exploit low radiative loss plasmonic resonance by combining a dark (subradiant) mode and a lattice resonance. We theoretically demonstrate that such dark-mode lattice resonances in periodic arrays of nanodisks or plasmonic crystals can be excited by vertically incident light beams. We investigate the excitation of lattice resonances in a finite sized, square-lattice plasmonic crystal by two types of cylindrical vector beams and a linearly polarized Gaussian beam. Quadrupole lattice resonances are excited by all three beams, and the largest peak intensity is obtained by using a specific type of cylindrical vector beam. Because of their lower radiative losses with many hotspots, the quadrupole lattice resonances in plasmonic crystal may pave the way for photonic research and applications that require strong light-matter interactions.

Comparison of Gait Motion Including Postoperative Trunk Deflection Between Direct Lateral and Anterolateral Approaches in Supine Total Hip Arthroplasty.

BACKGROUND: A prospective study was conducted to compare the effect of an anterolateral approach in the supine position (ALS) with that of a direct lateral (DL) approach on gait motion, including trunk deflection, in walking after total hip arthroplasty. We hypothesized that trunk deflection in walking after ALS would be significantly improved in comparison with use of the DL approach. METHODS: The subjects were 15 patients, with 7 in the ALS group and 8 in the DL group. Walking before and 9 and 28 weeks after surgery was analyzed using 3-dimensional motion analysis. RESULTS: Walking velocity, stride length, hip joint range of motion in the sagittal plane in walking, and locomotion range of trunk inclination were significantly improved 28 weeks after surgery in both groups. In gait analysis, there were no significant differences between the 2 groups. CONCLUSION: This study was conducted to compare the effect of ALS with that of a DL approach on locomotion in walking after total hip arthroplasty. Hip pain at 9 weeks after surgery was significantly improved using ALS compared to the DL approach, but there were no significant differences in gait function at 28 weeks after surgery using ALS or DL approach. Further long-term studies are required to examine differences between these procedures.

Excitation of multipole plasmons by optical vortex beams.

Localized surface plasmon resonance (LSPR) has been shown to exhibit a strong potential for nanoscale electromagnetic field manipulation beyond the diffraction limit. Particularly dark mode plasmons circumvent radiation loss and store the energy long in time, which raise the prospect of interesting plasmonics applications, for example biochemical sensing and nanoscale lasing. Here we theoretically investigate a method of exciting multipole plasmons, including dark modes, using normally incident light. By performing numerical calculations, we show that multipole plasmons in metal nanodisks can be selectively excited by circularly-polarized optical vortex beams. We study the electromagnetic fields of the beam cross-sections and their correspondence with the excited multipole plasmon modes with respect to spin and orbital angular momenta. The transfer of angular momentum between photons and plasmons is also discussed.

Correlation between the bone mineral density and stress on femur around a Duetto SI stem.

In cementless stem fixation, BMD reduction around the stem is of concern because it may cause loosening. This BMD reduction is assumed to be caused by stem implantation-induced alteration of the physiological feedback system, which may cause stress shielding and result in loosening, but the causal relationship has not been clarified. In this study, using a Duetto SI stem, we investigated the correlation between the postoperative BMD around the stem and stress. In patients who underwent their first THA at the orthopedic department of our university, the BMD was measured using DEXA, and FEA was performed with an equivalent time course. Time-course changes in the BMD, von Mises stress, and triaxial stress in Gruen zones 1 through 7 were calculated from those measured at 2 weeks and 5 months after surgery. The BMD and von Mises stress showed a bidirectional correlation when Gruen's classification was plotted on the horizontal axis. An increase in stress loaded on bone was assumed to be a factor increasing the BMD. The Duetto SI stem was fixed on the distal side, suggesting its stable fixation. BMD measurement and FEA were useful for quantification of the bone dynamics around the stem from an early phase.

Prevalence of radiographic findings of femoroacetabular impingement in the Japanese population.

BACKGROUND: Femoroacetabular impingement (FAI) is one factor known to cause pain and osteoarthritis (OA) of the hips. Although secondary OA due to hip dysplasia is common among Japanese populations, primary OA is seldom observed. Concomitantly, FAI is also thought to be uncommon in Japan, but relatively few epidemiological studies have addressed this issue. This study aimed to clarify the prevalence of radiographic findings of FAI in a Japanese population and to evaluate whether FAI is a risk factor for the development of arthritic changes. METHODS: We retrospectively examined 87 patients who underwent unilateral hip osteotomy with a Charnley category A hip joint on the contralateral side. Anteroposterior-view radiographs of the non-operated hip joint were assessed for the presence of hip dysplasia, as well as pistol grip deformity and crossover sign indicative of cam-type and pincer-type impingement, respectively. The presence of arthritic changes in the non-operated hip joint was assessed in follow-up radiographs, and factors contributing to the development of arthritis were determined by survival analysis. RESULTS: Of the 87 hips examined, dysplasia was noted in 38 (43.6%). While no pistol grip deformity was observed, crossover sign, which is indicative of pincer-type impingement, was identified in 9 of 38 dysplastic hips (23.7%) and 15 of 49 non-dysplastic hips (30.6%). Arthritic changes were present in 13 of 38 dysplastic hips (34.2%) and 11 of 49 non-dysplastic hips (22.4%). Survival analysis revealed that the presence of the crossover sign in non-dysplastic hips was significantly associated with the development of arthritis. CONCLUSIONS: The prevalence of the crossover sign in hips in a Japanese population is similar to that reported in Western populations, despite the fact that FAI is believed to be less prevalent in the Japanese population. Furthermore, the presence of the crossover sign in non-dysplastic hip joints is associated with the development of arthritis. Based on our results, pincer-type impingement could be commonly associated with the development of arthritis in Japanese populations.

Revision total hip arthroplasty using an interlocking stem with an allograft-prosthesis composite.

We report the clinical and radiographic outcomes and complications of revision surgery using a cementless interlocking stem with an allograft-prosthesis composite (APC). This study included 11 patients with an average follow-up of 73 years. Of the 11 revisions, 1 was aseptic, 7 were septic, and 3 were periprosthetic femoral fractures. The mean Harris hip score improved from 25.6 points before surgery to 74.8 points at final follow-up. Osseous union at the proximal allograft-host bone junction occurred in 10 hips (90.9%) ; the greater trochanter did not unite in 4 of 7 hips (57.1%). Moderate and severe allograft resorption occurred in one hip each. Postoperative complications included 1 deep infection, 2 heterotopic ossifications, and 1 dislocation. Using an interlocking stem with an allograft-prosthesis composite in revision surgery provided acceptable results in the presence of circumferential massive bone deficiency of the proximal femur.

Two-stage revision total hip arthroplasty for periprosthetic infections using antibiotic-impregnated cement spacers of various types and materials.

Antibiotic-impregnated hip cement spacers of various types and materials have been used in the treatment of periprosthetic hip infections. We developed a handmade spacer by using polymethylmethacrylate (PMMA) and/or α -tricalcium phosphate ( α -TCP). In this study, we retrospectively reviewed the surgical outcomes in 36 consecutive patients treated with 2-stage revision total hip arthroplasty by using our antibiotic-impregnated hip cement spacers. We aimed to analyze the infection control and reinfection rates after revision surgery. Moreover, we analyzed the possible predictors of postoperative reinfection. After exclusion of 1 patient who died immediately after the first-stage surgery, infection was controlled in 33 of the 36 hips (success rate, 91.7%). Two of these 33 hips underwent resection arthroplasty. Of the 36 hips that had been treated with the antibiotic-cement spacer, 31 hips (86.1%) were eligible for the second-stage prosthesis re-implantation. The 31 protocol hip joints of patients followed up for >6 months (mean, 48.6 months). Ten of these 31 hips (32.3%) became reinfected. No possible predictor examined differed significantly between the reinfection-positive and reinfection-negative groups. However, spacers consisting of PMMA cement alone were associated with the highest risk of reinfection. Therefore, α -TCP-containing antibiotic-impregnated hip cement spacers might decrease the reinfection rate in patients undergoing re-implantation.

Evaluation of bipolar hemiarthroplasty for the treatment of steroid-induced osteonecrosis of the femoral head.

PURPOSE: Bipolar hemiarthroplasty (BHA) for idiopathic osteonecrosis of the femoral head (ONFH) is performed at our institution. The purpose of this study was to evaluate the clinical and radiographic findings after BHA for the treatment of steroid -induced ONFH. METHODS: Thirty-seven hips in 27 patients were assessed (seven men, 11 hips; 20 women, 26 hips), average patient age at the time of surgery of 42.6 (range 20-83) years, with steroid-induced ONFH treated with BHA between 1995 and 2005. The mean follow-up duration was approximately ten (range five to 15) years. Patients were evaluated according to the Japan Orthopaedic Association (JOA) hip score. Kaplan-Meier survivorship was calculated to examine revision arthroplasty failure rate. Radiographic analysis of loosening included radiolucent lines and osteolysis of the acetabulum or femur. Causes of loosening were analysed using multiple logistic regression. RESULT: JOA hip score increased from 53 points (preoperative) to 87 points (final follow-up). Survival rates were 96.8 % and 78.6 % at ten and 15 years, respectively. Prosthesis loosening occurred on the acetabular side in five hips (13.5 %). No femoral-component loosening was observed. BHA had poor results in patients with Association Research Circulation Osseous (ARCO) stage IV ONFH and in patients under 40 years of age. CONCLUSION: BHA, with strict surgical indications, may be a good option for treating ONFH. Based on these results, total hip arthroplasty is recommended for patients with ARCO stage IV ONFH or for patients under 40 years of age.

Quality assessment for processed and sterilized bone using Raman spectroscopy.

To eliminate the potential for infection, many tissue banks routinely process and terminally sterilize allografts prior to transplantation. A number of techniques, including the use of scanning electron microscopy, bone graft models, and mechanical property tests, are used to evaluate the properties of allograft bone. However, as these methods are time consuming and often destroy the bone sample, the quality assessment of allograft bones are not routinely performed after processing and sterilization procedures. Raman spectroscopy is a non-destructive, rapid analysis technique that requires only small sample volumes and has recently been used to evaluate the mineral content, mineral crystallinity, acid phosphate and carbonate contents, and collagen maturity in human and animal bones. Here, to establish a quality assessment method of allograft bones using Raman spectroscopy, the effect of several common sterilization and preservation procedures on rat femoral bones were investigated. We found that freeze-thawing had no detectable effects on the composition of bone minerals or matrix, although heat treatment and gamma irradiation resulted in altered Raman spectra. Our findings suggest Raman spectroscopy may facilitate the quality control of allograft bone after processing and sterilization procedures.

Hammering sound frequency analysis and prevention of intraoperative periprosthetic fractures during total hip arthroplasty.

Adequate fixation at the time of cementless stem implantation depends on the operator's experience. An objective evaluation method to determine whether the stem has been appropriately implanted may be helpful. We studied the relationship between the hammering sound frequency during stem implantation and internal stress in a femoral model, and evaluated the possible usefulness of hammering sound frequency analysis for preventing intraoperative fracture. Three types of cementless stem (BiCONTACT®, SL-PLUS®, and AI-Hip®) were used. Surgeons performed stem insertion using a procedure similar to that employed in a routine operation. Stress was estimated by finite element analysis, the hammering force was measured, and frequency analysis of hammering sound data obtained using a microphone. Finite element analysis showed a decrease in the hammering sound frequency with an increase in the estimated maximum stress. When a decrease in frequency was observed, adequate hammering had occurred, and the continuation of hammering risked fracture. Based on the relationship between stress and frequency, the evaluation of changes in frequency may be useful for preventing the development of intraoperative fractures. Using our method, when a decrease in frequency is observed, the hammering force should be reduced. Hammering sound frequency analysis may allow the prediction of bone fractures that can be visually confirmed, and may be a useful objective evaluation method for the prevention of intraoperative periprosthetic fractures during stem insertion.

Hammering force during cementless total hip arthroplasty and risk of microfracture.

During cementless stem fixation, impaction of the stem is occasionally complicated by bony injuries. Small fractures not visible to the eye during surgery or on post-operative radiographs may remain undetected, and the incidence of such injuries may be underestimated. Employing the same techniques as those employed during total hip arthroplasty, we implanted cementless stems into artificial femora, with equivalent mechanical characteristics to living femora. The hammering force applied to the femur and the displacement of the stem and femur were measured using a load sensor and imaging, respectively. The von Mises stress generated in the femur during cementless stem press-fixation was also measured using finite element analysis. Average hammering force under these conditions (9.25 kN) was sufficient to cause damage to the artificial femur. The first two of eight hammer strikes caused most displacement of the stem. The von Mises stresses generated by the first and second hammer strikes were 31 and 68 MPa, respectively. Applying a high average hammering force to the stem after displacement has ceased probably contributes to the generation of intraoperative fractures during cementless stem fixation. Given that two strikes appeared to be sufficient, we believe that hammering force should be reduced to a micro-adjustment level after the second hit.