Do Mortality and Complication Rates Differ Between Periprosthetic and Native Hip Fractures?

BACKGROUND: Epidemiological estimates indicate a rising incidence of periprosthetic hip fractures. While native hip fractures are known to be a highly morbid condition, a significant body of research has led to improved outcomes and decreased complications following these injuries. Comparatively, little research has evaluated the relative morbidity and mortality of periprosthetic hip fractures. The purpose of this study was to compare the morbidity and mortality of periprosthetic vs native hip fractures. METHODS: Using the National Surgical Quality Improvement Program (NSQIP) database, 523 periprosthetic hip fractures were matched to native hip fractures using propensity scores. The 30-day rates of complications were compared using McNemar's test. A multivariate regression was then used to determine independent risk factors for mortality following periprosthetic fracture. RESULTS: Mortality was similar between groups (periprosthetic: 2.7% vs native: 3.4%; P = .49). Periprosthetic fractures exhibited a greater rate of overall (63.1% vs 38.6%; P < .001) and minor complications (59.1% vs 34.4%; P < .001). There was an increased rate of return to the operating room (7.8% vs 3.1%; P < .001) and blood transfusion in the periprosthetic group (54.9% vs 30.2%; P = .001). Age greater than 85 (odds ratio 9.21) and dependent functional status (odds ratio 5.38) were both independent risk factors for mortality following periprosthetic fracture. CONCLUSIONS: While native hip fractures are known to be highly morbid, our findings suggest that periprosthetic hip fractures have a similar mortality with significantly higher short-term morbidity. Future research is warranted to better understand risk factors and prevention strategies for complications in this subset of patients.

Acetabular Focal Chondral Lesions Are Not Associated With Worse Outcomes After Periacetabular Osteotomy: A Matched Group Analyses.

BACKGROUND: The purpose of this study was to assess the outcomes of patients who underwent combined hip arthroscopy and periacetabular osteotomy with acetabular focal chondral defects and compare these outcomes with a group of patients without focal chondral defects. METHODS: A retrospective review looking at patients who underwent hip arthroscopy and/or periacetabular osteotomy was performed. Minimum 2-year follow-up, Tönnis grade 0-1, and a Beck chondromalacia stages 4-5 were included. Twenty-eight hips met inclusion criteria. These patients were then matched 1:1 and compared. RESULTS: The average acetabular chondral defect size was 144.3 mm2 ± standard deviation 116.2. Postoperative, modified Harris Hip Score, Hip Disability and Osteoarthritis Outcome Score, and University of California Los Angeles scores were similar between groups (P = .382, P = .755, P = .763, respectively). At the last follow-up, Tönnis grade was similar between groups (P = .552). No association between having a defect and increased risk of failure was noted (hazard ratio 1.35 [95% CI 0.43-4.24], P = .607). CONCLUSION: We found that patients with focal chondral defects did similar to a comparison group of patients without chondral defects.

High Rate of Failure After Revision of a Constrained Liner.

BACKGROUND: The purpose of this study was to examine the outcomes of repeat revision after failure of a constrained liner. METHODS: We reviewed 1212 consecutive revisions and identified 74 (6%) revisions of a failed constrained liner in 46 patients with a mean age of 65 years. The most common reasons for revision of a constrained liner were recurrent instability (64.9%) and infection (25.7%). RESULTS: At a mean of 35 months, 42 of the 74 hips (57%) required repeat revision. Kaplan-Meier revision-free survival was 24% at 10 years. Thirty-two of the 74 revisions (43%) had a dislocation event after the index revision. Kaplan-Meier dislocation-free survival was 43% at 10 years. There was a higher failure rate among the 34 patients with abductor deficiency (hazard ratio 1.90, 95% confidence interval, 1.06-3.43; P = .032). CONCLUSION: Patients undergoing revision of a failed constrained liner have a high likelihood of recurrent dislocation and repeat revision surgery. LEVEL OF EVIDENCE: Level IV.

Femoroacetabular Impingement and Pelvic Incidence: Radiographic Comparison to an Asymptomatic Control.

PURPOSE: To investigate whether pelvic incidence (PI) in patients with symptomatic femoroacetabular impingement was different from that in a normal population. METHODS: Retrospective analysis of 30 consecutive female and 30 consecutive male patients with computed tomography scans who underwent hip arthroscopy for FAI. PI was measured using scout lateral radiographs. The center-edge angle (CEA), acetabular version, and α angle were also measured. Each patient was subcategorized as having a cam-type deformity (α angle >55°), a deep socket deformity (CEA >39°), and/or a retroverted acetabulum (acetabular anteversion <15°). Our group and subgroups were compared with a historical control group from a previously published study of 300 volunteers. Each group was compared using a Student t test. RESULTS: Our mean PI was 49.31° ± 12.34° (range, 28.4°-79.5°), less than the asymptomatic historical control (n = 300) with a mean PI of 55.0° ± 10.6° (range, 33°-82°) (P < .001). The subgroups for cam deformity, deep socket deformity, and acetabular retroversion have a mean PI of 48.89° ± 11.81°, 38.30° ± 7.56°, and 44.93° ± 11.32°, respectively. All had a significantly lower PI than the historical control (P < .001, P < .001, P < .001, respectively). CONCLUSIONS: We conclude that patients presenting with FAI may have a lower PI than the general population. The clinical significance of a 5.7° difference in PI remains unknown. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Revision Total Hip Arthroplasty With a Monoblock Splined Tapered Grit-Blasted Titanium Stem.

BACKGROUND: In revision total hip arthroplasty (THA), proximal femoral bone loss creates a challenge of achieving adequate stem fixation. The purpose of this study was to examine the outcomes of a monoblock, splined, tapered femoral stem in revision THA. METHODS: Outcomes of revision THA using a nonmodular, splined, tapered femoral stem from a single surgeon were reviewed. With a minimum of 2-year follow-up, there were 68 cases (67 patients). Paprosky classification was 3A or greater in 85% of the cases. Preoperative and postoperative Harris Hip Scores (HHS), radiographic subsidence and osseointegration, limb length discrepancy, complications, and reoperations were analyzed. RESULTS: The Harris Hip Score improved from 37.4 ± SD 19.4 preoperatively to 64.6 ± SD 21.8 at final follow-up (P < .001). There were 16 revision procedures-8 for septic indications and 8 for aseptic indications. Subsidence occurred at a rate of 3.0% and dislocation at 7.4%. Limb length discrepancy of more than 1 cm after revision was noted in 13.6% of patients. Bone ingrowth was observed in all but 4 patients (94.1%). At 4-year follow-up, Kaplan-Meier estimated survival was 72.9% (95% confidence interval [CI] 57.0-83.8) for all causes of revision, 86.6% (95% CI 72.0-93.9) for all aseptic revision, and 95.5% (95% CI 86.8-98.5) for aseptic femoral revision. CONCLUSION: Although complications were significant, revision for femoral aseptic loosening occurred in only 3 patients. Given the ability of this monoblock splined tapered stem to adequately provide fixation during complex revision THA, it remains a viable option in the setting of substantial femoral bone defects.

Radiographic Comparison of Anterior Acetabular Rim Morphology Between Pincer Femoroacetabular Impingement and Control.

PURPOSE: To define and compare 3 new parameters (anterior rim angle [ARA], anterior wall angle [AWA], and anterior margin ratio [AMR]), in addition to the lateral center-edge angle of Wiberg and the Tönnis angle, for measuring pincer-type femoroacetabular impingement (FAI) in an asymptomatic versus symptomatic FAI population. METHODS: We reviewed anteroposterior pelvis radiographs of patients verified to have no hip complaints between December 2009 and December 2011. We also reviewed anteroposterior pelvis radiographs of patients who underwent a rim-trimming procedure for pincer FAI between December 2010 and December 2011. Patients aged older than 65 years or younger than 18 years were excluded. Radiographs with a Tönnis grade of 2 or greater were also excluded. For the group of patients with symptomatic hip impingement, radiographs that did not have a crossover sign were excluded. The 2 cohorts were matched for age, sex, and body mass index. Measurements included the Tönnis angle, lateral center-edge angle of Wiberg, ARA, AWA, and AMR. These measurements were compared between the groups. RESULTS: Seventy-two asymptomatic hips were measured. There were 44 female patients (61%) and 28 male patients (39%), aged 25 to 51 years, in the asymptomatic group. The mean ARA was 88.91° ± 8.06°, the mean AWA was 34.89° ± 8.09°, and the mean AMR was 0.49 ± 0.15. Seventy-two symptomatic hips were measured. There were 40 female patients (56%) and 32 male patients (44%), aged 27 to 58 years, in the symptomatic group. The mean ARA was 82.98° ± 10.82°, the mean AWA was 39.11° ± 9.00°, and the mean AMR was 0.56 ± 0.14. The mean difference in the ARA between asymptomatic patients and symptomatic patients was 5.92° (P = .0001). The mean difference in the AWA was 4.22° (P = .0019). The mean difference in the AMR was 0.07 (P = .0039). CONCLUSIONS: Our study provides information on several measurements within an asymptomatic cohort and a symptomatic cohort. Although we found statistically significant differences between the 2 populations, the clinical significance remains unknown. We recommend using this asymptomatic population as a guideline for limits on resection of the anterior acetabular rim. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Does Hip Arthroscopy Affect the Outcomes of a Subsequent Total Hip Arthroplasty?

BACKGROUND: Hip arthroscopy utilization is on the rise in the United States. Thus, determining the impact of prior hip arthroscopy on subsequent total hip arthroplasty (THA) is important to understand. METHODS: A retrospective review of a high-volume orthopedic surgery practice's billing database yielded 42 hip arthroscopies that underwent subsequent THA. An age-, sex-, and body mass index (2:1)-matched cohort of primary THAs was used for comparison. RESULTS: No difference was observed in the postoperative Harris Hip Score between groups (92.1 ± 10.9 vs 90.1 ± 6.6, P = .20); however, there was greater overall improvement in Harris Hip Score in the control group (40.4 ± 18.4 vs 45.1 ± 8.7, P = .05). There were no differences observed in the complication (P = .5) or revision rates (P = .4). CONCLUSION: With the numbers available, prior hip arthroscopy does not appear to have an impact on the functional outcomes of a subsequent THA.

Do Complication Rates Differ by Gender After Metal-on-metal Hip Resurfacing Arthroplasty? A Systematic Review.

BACKGROUND: Although metal-on-metal (MoM) bearing surfaces provide low rates of volumetric wear and increased stability, evidence suggests that certain MoM hip arthroplasties have high rates of complication and failure. Some evidence indicates that women have higher rates of failure compared with men; however, the orthopaedic literature as a whole has poorly reported such complications stratified by gender. QUESTIONS/PURPOSES: This systematic review aimed to: (1) compare the rate of adverse local tissue reaction (ALTR); (2) dislocation; (3) aseptic loosening; and (4) revision between men and women undergoing primary MoM hip resurfacing arthroplasty (HRA). METHODS: Systematic MEDLINE and EMBASE searches identified all level I to III articles published in peer-reviewed journals, reporting on the outcomes of interest, for MoM HRA. Articles were limited to those with 2-year followup that reported outcomes by gender. Ten articles met inclusion criteria. Study quality was evaluated using the Modified Coleman Methodology Score; the overall quality was poor. Heterogeneity and bias were analyzed using a Mantel-Haenszel statistical method. RESULTS: Women demonstrated an increased odds of developing ALTR (odds ratio [OR], 5.70 [2.71-11.98]; p<0.001), dislocation (OR, 3.04 [1.2-7.5], p=0.02), aseptic loosening (OR, 3.18 [2.21-4.58], p<0.001), and revision (OR, 2.50 [2.25-2.78], p<0.001) after primary MoM HRA. CONCLUSIONS: A systematic review of the currently available literature reveals a higher rate of complications (ALTR, dislocation, aseptic loosening, and revision) after MoM HRA in women compared with men. Although femoral head size has been frequently implicated as a prime factor in the higher rate of complication in women, further research is necessary to specifically probe this relationship. Retrospective studies of data available (eg, registry data) should be undertaken, and moving forward studies should report outcomes by gender (particularly complications). LEVEL OF EVIDENCE: Level III, therapeutic study.

The False-Profile View May Be Used to Identify Cam Morphology.

PURPOSE: To identify the accuracy of measuring the alpha angle on the false-profile, anteroposterior (AP), and 90° Dunn lateral views of the hip as compared with computed tomography (CT) scan findings. METHODS: Forty patients were needed to have power greater than 80%. Forty-five consecutive patients undergoing hip arthroscopy were retrospectively reviewed with preoperative radial oblique CT reformatted scans and plain radiographs. Alpha angles were measured on plain radiographs (AP, 90° Dunn lateral, and false profile) and CT reformatted views. Abnormal alpha angles were considered greater than 50.5°. Two orthopaedic surgeons independently measured the images, and the results were compared between imaging modalities. RESULTS: The false-profile view was 60% sensitive and 89.0% specific for diagnosing cam deformities of the hip. All radiographs combined were 86% sensitive and 75% specific for diagnosing cam deformities. The false-profile view most strongly correlated with the 2-o'clock (R = 0.746, P = .001) and 3-o'clock (R = 0.698, P < .0001) positions. An intraclass correlation coefficient of 0.81 was found for measurement of the alpha angle on the false-profile view. CONCLUSIONS: This study has proved that the false-profile view effectively characterizes cam deformity, especially anterior deformity at the 3-o'clock position. Measuring the alpha angle on the false-profile view appears to be reproducible. The false-profile view along with standing AP pelvis and 90° Dunn lateral views of the hip comprises a good screening radiographic series for patients presenting with symptoms of femoroacetabular impingement. LEVEL OF EVIDENCE: Level III, diagnostic study.

Does Neuraxial Anesthesia Decrease Transfusion Rates Following Total Hip Arthroplasty?

Perioperative transfusions increase complications and cost following THA. Current series evaluating neuraxial anesthesia and blood loss following THA are small and utilize heterogeneous populations. Using the NSQIP database we compared transfusion rates following THA with neuraxial and general anesthesia. Between 2005 and 2012, 28,857 THAs (11,317 neuraxial anesthesia) were identified. Univariate analysis showed lower rates of transfusion, pneumonia, unplanned intubation, prolonged intubation, stroke, all complications, and medical complications in the neuraxial group. Operative time and length of stay were shorter with neuraxial anesthesia as well. After adjusting for patient comorbidities, a multivariate regression model showed fewer transfusions with neuraxial anesthesia. The multivariate regression model showed additional independent risk factors for transfusion including gender, operative time, elevated INR, and a history of hypertension, metastatic cancer, and renal failure.

An analysis of references used for the Orthopaedic In-Training Examination: what are their levels of evidence and journal impact factors?

BACKGROUND: Although the references recommended for the Orthopaedic In-Training Examination (OITE) have been evaluated in certain subspecialty domains, suggested reference level of evidence (LOE), impact factor, and citation age have not been evaluated comprehensively to our knowledge. QUESTIONS/PURPOSES: We present an analysis of all references cited in the OITE recommended readings for each test question including the duration of time between their initial publication and their use in the OITE, which we defined as citation age, LOE, and the impact factor of the journals referenced. METHODS: We evaluated all references for the 2010 to 2012 OITE administrations (three examinations; 825 questions total). Publication characteristics, including citation age, were noted. The LOE for each journal article and the impact factor of each journal were determined; differences in LOE and impact factor were compared between test sections. A total of 1817 references were cited in the 825 questions we evaluated; this denominator was used in all calculations that follow. RESULTS: The recommended reading references included 1337 journal article references (74%), 469 text references (26%), and 11 multimedia sources (0.6%; eg, websites, instructional DVDs). The three most commonly recommended journals were general orthopaedic journals, The Journal of Bone and Joint Surgery (American Volume), Journal of American Academy of Orthopaedic Surgeons, and Clinical Orthopaedics and Related Research. The majority (72.2%) of the cited journal references were published within 10 years of the test date, with a mean ± SD citation age of 8.3 ± 7.4 years. The majority of the cited journal articles were Levels IV and V evidence (mean, 4.16 ± 1.1). The Spine section had higher LOE (3.74; p < 0.001), although the practical relevance of such a difference is questionable, as all but two sections' LOE rounded to Level IV evidence. The Spine and Basic Science sections were published in journals with a larger mean impact factor (Basic Science, 7.16 ± 12.67; Spine, 5.73 ± 12.08; p < 0.001). CONCLUSIONS: Our data show that the majority of the recommended readings for the OITE stem from higher impact general orthopaedic and major subspecialty journals. Furthermore the observed mean LOE of the recommended readings shows a preponderance of Levels IV and V research. These data may suggest that test-takers may find benefit in the review of high-level general orthopaedic journals, and review articles in particular while preparing for the OITE, although further study is necessary to determine optimal test preparation strategies. Finally, our study provides a baseline analysis of the study designs of OITE recommended references, and may provide insight for educators designing resident educational curricula.

Does resident involvement impact post-operative complications following primary total knee arthroplasty? An analysis of 24,529 cases.

Little is known about the impact of resident involvement on complication rates following total knee arthroplasty (TKA). The goal of our study was to determine the impact of resident involvement on complications following primary TKA. Using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database (2005-2012) we identified 24,529 patients who underwent primary TKA. Of these, 5960 (24.3%) had a resident involved in a primary TKA. Using a multivariate logistic regression which incorporated propensity score adjustment, no differences were seen in morbidity and mortality following those cases with resident involvement (OR: 1.15, P = 0.129). In the first large scale, comprehensive analysis of resident impact on short-term morbidity and mortality, no increase in complications was observed with resident involvement in primary TKA.

Resident involvement does not influence complication after total hip arthroplasty: an analysis of 13,109 cases.

Our study aimed to determine the impact of resident involvement on the 30-day postoperative complication rates following primary total hip arthroplasty (THA). Using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database, 13,109 primary THAs were identified, of which 3462 (26.4%) had resident involvement. Neither univariate (4.45% vs 4.52%, P = 0.86) nor multivariate (OR 1.04, P = 0.75) analyses demonstrated an increased complication rate with resident involvement following THA. We did find, however, that increased operative time, comorbidities, age, obesity, prior history of stroke and/or cardiac surgery were all independent risk factors for short-term complication. Our findings suggest that resident involvement does not increase 30-day complication rates following primary THA.

Operative treatment of femoroacetabular impingement.

Femoroacetabular impingement is a common pathologic disorder of the hip that causes pain and has been implicated in the development of early osteoarthritis in young adults. This disorder includes 2 different subtypes: cam impingement and pincer impingement. When nonsurgical treatment methods fail, surgical options are indicated. These options have been increasingly investigated over recent years and show promising results. Several surgical techniques have been described, including surgical dislocation of the hip, mini-open procedures, hip arthroscopy, and periacetabular osteotomies. Nevertheless, the preferred mode of surgical management of femoroacetabular impingement remains a source of controversy. Only short-term and midterm outcome data are available regarding the efficacy of these surgical techniques. This review details 5 approaches for surgical management of femoroacetabular impingement: open surgical dislocation, a combined arthroscopic and open approach, hip arthroscopy, a mini-open anterior approach, and periacetabular osteotomy. It focuses specifically on surgical technique, outcomes, and their efficacy in treatment of femoroacetabular impingement.

Evaluation of hip pain in young adults.

Hip pain is a common complaint in the young, athletic patient population. Primary, intra-articular sources of hip pain are becoming increasingly recognized by primary care providers and sports medicine specialists. Prior to deciding among the various treatment options for the many sources of hip pain in the athletic patient population, the clinician must be able to recognize and accurately diagnose the underlying pathology. Advances in imaging modalities and our understanding of the pathophysiology have improved our ability to accurately understand and diagnose the source of hip pain in this patient population. This review presents a comprehensive strategy for the workup and diagnosis of young, athletic patients presenting with hip pain, and provides the sports medicine specialist with the tools to correlate the patient's history, physical examination, and imaging findings and to treat these challenging patients.

A robust method for estimating regional pulmonary parameters in presence of noise.

RATIONALE AND OBJECTIVES: Estimation of regional lung function parameters from hyperpolarized gas magnetic resonance images can be very sensitive to presence of noise. Clustering pixels and averaging over the resulting groups is an effective method for reducing the effects of noise in these images, commonly performed by grouping proximal pixels together, thus creating large groups called "bins." This method has several drawbacks, primarily that it can group dissimilar pixels together, and it degrades spatial resolution. This study presents an improved approach to simplifying data via principal component analysis (PCA) when noise level prohibits a pixel-by-pixel treatment of data, by clustering them based on similarity to one another rather than spatial proximity. The application to this technique is demonstrated in measurements of regional lung oxygen tension using hyperpolarized (3)He magnetic resonance imaging (MRI). MATERIALS AND METHODS: A synthetic dataset was generated from an experimental set of oxygen tension measurements by treating the experimentally derived parameters as "true" values, and then solving backwards to generate "noiseless" images. Artificial noise was added to the synthetic data, and both traditional binning and PCA-based clustering were performed. For both methods, the root-mean-square (RMS) error between each pixel's "estimated" and "true" parameters was computed and the resulting effects were compared. RESULTS: At high signal-to-noise ratios (SNRs), clustering did not enhance accuracy. Clustering did, however, improve parameter estimations for moderate SNR values (below 100). For SNR values between 100 and 20, the PCA-based K-means clustering analysis yielded greater accuracy than Cartesian binning. In extreme cases (SNR<5), Cartesian binning can be more accurate. CONCLUSIONS: The reliability of parameters estimation in imaging-based regional functional measurements can be improved in the presence of noise by utilizing principal component analysis-based clustering without sacrificing spatial resolution compared to Cartesian binning. Results suggest that this approach has a great potential for robust grouping of pixels in hyperpolarized (3)He MRI maps of lung oxygen tension.

Five to Ten-Year Results of the Birmingham Hip Resurfacing Implant in the U.S.: A Single Institution's Experience.

BACKGROUND: International surgeon series and registry data have demonstrated positive outcomes and long-term survival of the Birmingham Hip Resurfacing (BHR) implant. We report the 5 to 10-year results from a single center in the U.S. METHODS: Three hundred and fourteen patients (360 hips) underwent surface replacement arthroplasty with use of the BHR implant and consented to study participation. Patient-reported outcomes and complication and revision data were collected at a minimum of 5 years of follow-up for 93% (324 of 350) of the hips in surviving patients. A matched-cohort analysis was used to compare clinical outcomes between use of the BHR and total hip arthroplasty. RESULTS: Mean modified Harris hip score (mHHS) and University of California, Los Angeles (UCLA) scores significantly improved postoperatively, to 89.9 and 8.0, respectively (p < 0.001). The Kaplan-Meier estimated rate of survival for all-cause revision was 97.2% (95% confidence interval [CI], 94.7% to 98.5%) and 93.8% (95% CI, 88.8% to 96.7%) at 5 and 10 years, respectively. In a subgroup analysis of patients fitting our current BHR inclusion criteria (males <60 years of age with a diagnosis of osteoarthritis and anatomy conducive to a femoral head component of ≥48 mm), survival free of aseptic revision was 99.5% (95% CI, 96.6% to 99.9%) at 5 years and 98.2% (95% CI, 94.4% to 99.4%) at 10 years. Fourteen patients (4.3% of all hips) required revision. Postoperative UCLA scores were significantly greater for BHR compared with total hip arthroplasty (mean score of 8.0 ± 2.0 versus 7.6 ± 1.8; p = 0.040) in a matched-cohort analysis, with patients matched according to preoperative UCLA score, diagnosis, age, sex, and body mass index. Among matched patients who were highly active preoperatively (UCLA score of 9 to 10), BHR provided a smaller median decrease in the postoperative UCLA score (0.0 versus 1.0; p < 0.001), which was clinically important according to the minimal clinically important difference (MCID, 0.92). Furthermore, BHR provided a greater likelihood of remaining highly active compared with total hip arthroplasty (61% compared with 20%; p < 0.001). CONCLUSIONS: BHR demonstrated excellent survivorship and clinical outcomes at 5 to 10 years in selected patients. As compared with total hip arthroplasty, the use of the BHR may provide highly active patients with clinically important advantages in postoperative activity as well as a greater likelihood of remaining highly active. Continued follow-up is necessary to validate long-term BHR outcomes. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.