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.

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.

Involvement of Residents Does Not Increase Postoperative Complications After Open Reduction Internal Fixation of Ankle Fractures: An Analysis of 3251 Cases.

Ankle fractures are common injuries frequently treated by foot and ankle surgeons. Therefore, it has become a core competency for orthopedic residency training. Surgical educators must balance the task of training residents with optimizing patient outcomes and minimizing morbidity and mortality. The present study aimed to determine the effect of resident involvement on the 30-day postoperative complication rates after open reduction and internal fixation of ankle fractures. A second objective of the present study was to determine the independent risk factors for complications after this procedure. We identified patients in the American College of Surgeons National Surgical Quality Improvement Program database who had undergone open reduction internal fixation for ankle fractures from 2005 to 2012. Propensity score matching was used to help account for a potential selection bias. We performed univariate and multivariate analyses to identify the independent risk factors associated with short-term postoperative complications. A total of 3251 open reduction internal fixation procedures for ankle fractures were identified, of which 959 (29.4%) had resident involvement. Univariate (2.82% versus 4.54%; p = .024) and multivariate (odds ratio 0.71; p = .75) analyses demonstrated that resident involvement did not increase short-term complication rates. The independent risk factors for complications after open reduction internal fixation of ankle fractures included insulin-dependent diabetes, increasing age, higher American Society of Anesthesiologists score, and longer operative times.

Is Radiation Necessary for Treatment of Non-Hodgkin's Lymphoma of Bone? Clinical Results With Contemporary Therapy.

BACKGROUND: Non-Hodgkin's lymphoma (NHL) of bone is a rare musculoskeletal malignancy accounting for fewer than 7% of bone cancers. Traditionally, we have treated patients who have NHL of bone with chemotherapy and radiation therapy, but the role of radiotherapy in disease management and patient functional outcomes after treatment have not been well studied. We investigated the survival advantage of radiotherapy in a large cohort of patients with NHL of bone and assessed associated patient complications of radiotherapy. QUESTIONS/PURPOSES: The objective of this study was to compare patients treated for NHL of bone with and without radiation in terms of (1) overall survival; (2) pretreatment complications; (3) posttreatment complications; and (4) functional outcomes using the Musculoskeletal Tumor Society (MSTS) score. METHODS: A retrospective analysis of all patients with biopsy-proven NHL of bone diagnosed at our institution between 1985 and 2013 was undertaken; 70 patients met our criteria for inclusion with minimum followup of 6 months (median, 55 months; range, 10-219 months). Overall survival at 5 and 10 years was estimated and compared between two groups of patients: one group treated with systemic therapy alone (chemotherapy, rituximab; 46 patients [66%]) and the other with combined modality therapy (systemic therapy and radiotherapy; 24 patients [34%]). During the period in question, indications for radiotherapy included bulky disease, an abbreviated course of systemic therapy, and an incomplete response to systemic therapy. Patients not meeting these criteria generally received systemic therapy alone. With the available sample size, it was estimated that a difference in survival of approximately 30% would have to be present for detection with 80% power (α = 0.05, ß = 0.2, n = 70, Δ = 30%). Pretreatment and posttreatment complications occurring in both patient groups were retrospectively reviewed with special emphasis on fracture healing after treatment. MSTS scores were obtained for 45 patients with appendicular tumors at a median followup of 42 months (range, 10-215 months). RESULTS: With the data available, no difference in Kaplan-Meier survivorship was observed between patients treated with and without radiation at 5 years (98%; 95% confidence interval [CI], 93%-100% versus 95%; 95% CI, 85%-100%; p = 0.281). Patients who were treated with radiation were more likely to experience problems with fracture healing (relative risk [RR], 12.8; 95% CI, 1.8-89.8; p = 0.01). Similarly, patients treated with radiation were at a higher risk for fracture in the posttreatment period (five of 24 versus no radiation zero of 46; RR, 20.7; 95% CI, 1.2-359.0; p = 0.0375). MSTS scores were poorer in patients treated with radiation (75% versus 91%; p = 0.034) attributable in part to a higher incidence of bony complications in this group after treatment. CONCLUSIONS: Based on the numbers of patients in our study, we could not demonstrate a survival advantage with radiation use. Rather, radiotherapy may be associated with orthopaedic complications occurring during and after treatment. Larger, prospective studies are necessary to definitively establish whether radiation is necessary for the treatment of patients with lymphoma of bone. LEVEL OF EVIDENCE: Level III, therapeutic study.

Is There a Benefit to Head Size Greater Than 36 mm in Total Hip Arthroplasty?

This study compares the rate of dislocation and revision for instability between 36-mm and anatomic femoral heads (large diameter metal-on-metal THA, dual-mobility bearings, and hip resurfacing arthroplasty) in patients at high risk for dislocation. A total of 501 high-risk patients, over a 10-year period, were identified (282 36-mm THA, 24 dual-mobility bearings, 83 metal-on-metal arthroplasty, and 112 hip resurfacing arthroplasty). There were 13 dislocations in the 36-mm group compared to 1 in the anatomic group (4.6% vs 0.5%; P = .005). Four patients dislocated more than once in the 36-mm group (1.4% vs 0%; P = .04), and 2 patients in the 36-mm group required a revision for instability (0.7% vs 0%; P = .11). These results suggest that anatomic head sizes significantly lower the risk of dislocation in high-risk patients.

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 resident involvement have an impact on postoperative complications after total shoulder arthroplasty? An analysis of 1382 cases.

BACKGROUND: The impact of resident involvement on total shoulder arthroplasty (TSA) complication rate is unknown. The purpose of this study was to assess whether resident involvement in TSA is associated with 30-day complication rates. METHODS: The American College of Surgeons National Surgical Quality Improvement Program database was searched for all patients who underwent TSA between 2005 and 2012. Data were extracted for patient preoperative demographics, intraoperative variables, resident involvement in surgery, and 30-day postoperative complications. Resident and nonresident cases were grouped by a matched propensity score analysis. Univariate and multivariate analysis was performed to assess the effect of resident involvement on postoperative complications. RESULTS: We analyzed 1382 patients who underwent primary TSA, with matched groups of 691 with and 691 without resident involvement. The overall rate of 30-day complications was 2.60% in TSAs in which a resident was involved compared with 3.91% when no resident was involved (P = .173). Operative time and hospital stay were shorter in cases in which a resident was present (P = .002 and P < .001, respectively). Independent risk factors significantly associated with TSA complications identified by multivariate regression were higher patient age, higher American Society of Anesthesiologists classification, congestive heart failure, insulin-dependent diabetes, and peripheral vascular disease. CONCLUSION: Resident involvement in TSA procedures is not a risk factor for 30-day complications. Patient factors including increased age, diabetes, and cardiac disease are risk factors for TSA complications. This information can be used in preoperative counseling to reassure patients about safety of resident involvement in TSA and to optimize patient comorbidities before surgery.

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.

Blastomyces Tenosynovitis of the Foot and Ankle: A Case Report and Review of the Literature.

Deep fungal infection localized to the foot is not common, and when it occurs it often affects immunocompromised individuals. In this report, we describe the case of an adult diabetic patient who suffered with with Blastomycosis infection of the flexor digitorum longus and peroneal tendon sheaths. The condition was treated with systemic antifungal therapy and surgical debridement.

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.

Weighted versus uniform dose of tranexamic acid in patients undergoing primary, elective knee arthroplasty: a prospective randomized controlled trial.

In a prospective, randomized, double-blinded, controlled study (25 controls), TA was infused parenterally before tourniquet release in two study groups. Group 1 (n = 20) received a 1 g dose, and group 2 (n = 20) received a 20 mg/kg dose. There was no significant difference between groups 1 and 2 with intra-operative, post-operative and total blood loss. Both groups 1 and 2 exhibited significant improvements in intra-operative, post-operative, and total blood loss compared to the control group (P < 0.05). Two blood transfusions were given to one patient in the weighted group, compared to 19 transfusions (10 patients) in the control group. This study suggests that a single 1-g dose can be used with the same efficacy as a weighted 20 mg/kg dose.

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.

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.

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.

Physical activity is associated with magnetic resonance imaging-based knee cartilage T2 measurements in asymptomatic subjects with and those without osteoarthritis risk factors.

OBJECTIVE: To evaluate the association of exercise and knee-bending activities with magnetic resonance imaging (MRI)-based knee cartilage T2 relaxation times and morphologic abnormalities in asymptomatic subjects from the Osteoarthritis Initiative, with or without osteoarthritis (OA) risk factors. METHODS: We studied 128 subjects with knee OA risk factors and 33 normal control subjects ages 45-55 years, with a body mass index of 18-27 kg/m(2) and no knee pain. Subjects were categorized according to exercise level, using the leisure activity component of the Physical Activity Scale for the Elderly, and by self-reported frequent knee-bending activities. Two radiologists graded the cartilage of the right knee on MR images, using the Whole-Organ MRI Score (WORMS). Cartilage was segmented, and compartment-specific T2 values were calculated. Differences between the exercise groups and knee-bending groups were determined using multiple linear and logistic regression models. RESULTS: Among subjects with risk factors for knee OA, light exercisers had lower T2 values compared with sedentary and moderate/strenuous exercisers. When the sexes were analyzed separately, female moderate/strenuous exercisers had higher T2 values compared with sedentary individuals and light exercisers. Subjects without risk factors displayed no significant differences in T2 values according to exercise level. However, frequent knee-bending activities were associated with higher T2 values in both subjects with OA risk factors and those without OA risk factors and with more severe cartilage lesions in the group with risk factors. CONCLUSION: In subjects at risk of knee OA, light exercise was associated with low T2 values, whereas moderate/strenuous exercise in women was associated with high T2 values. Higher T2 values and WORMS grades were also observed in frequent knee-benders, suggesting greater cartilage degeneration in these individuals.

Evaluating rotational kinematics of the knee in ACL-ruptured and healthy patients using 3.0 Tesla magnetic resonance imaging.

PURPOSE: Rotational knee laxity is an important measure in restoring knee stability following anterior cruciate ligament (ACL) injury, but is difficult to quantify with current clinical tools. The hypothesis of the study is that there is greater tibial rotation (TR) in women than men, and also in ACL-deficient than healthy knees. METHODS: Sixteen healthy (8 men, 26.8 ± 6.4 years; 8 women, 26.9 ± 3.8 years) and ten ACL-deficient (5 men, 33.6 ± 10.5 years; 5 women, 36.3 ± 10.7 years) subjects received bilateral knee MRI in 15° of flexion using a custom device to apply a constant axial compressive load (44 N). A rotational torque (3.35 Nm) was sequentially applied to obtain images at internal and external rotation positions. T (2)-weighted images were acquired in internal and external rotation. Images were segmented and TR was calculated. To assess reproducibility, six knees were scanned twice on separate days. Group comparisons were made with unpaired t tests, while intrasubject comparisons were made using paired t tests. RESULTS: Healthy women demonstrated greater TR than men (13.6° ± 4.7° vs. 8.3° ± 3.6°; P = 0.001). Male ACL-deficient knees showed greater TR than the contralateral knee (15.7° ± 6.9° vs. 7.7° ± 5.6°; P = 0.003), and compared to male controls (P = 0.002). ACL-deficient women showed greater TR compared to their contralateral leg (15.1° ± 2.3° vs. 10.0° ± 4.3°; P = 0.01). The intraclass correlation coefficient of the TR measurement was 0.913, and the SEM = 1.1°. CONCLUSIONS: Kinematic MRI is a reproducible method to quantify total knee rotation. Women have more rotational laxity than men, particularly in the external rotation position. ACL rupture leads to increased rotational laxity of the knee. LEVEL OF EVIDENCE: Retrospective case-control series, Level III.

Magnetic resonance imaging evaluation of knee kinematics after anterior cruciate ligament reconstruction with anteromedial and transtibial femoral tunnel drilling techniques.

PURPOSE: The purpose of this study was to use magnetic resonance (MR) imaging to evaluate the translational and rotational kinematics of anterior cruciate ligament (ACL) reconstructed knees with transtibial (TT) and anteromedial (AM) femoral tunnel drilling. METHODS: ACL reconstruction was performed in 21 subjects: 12 with AM drilling (5 men and 7 women; mean age, 33 ± 9 years; imaged 18 ± 5 months after surgery) and 9 with TT drilling (5 men and 4 women; mean age, 32 ± 9 years; imaged 12 ± 8 months after surgery). Three-tesla MR imaging was obtained bilaterally at extension and 30° to 40° of flexion under simulated loading (125 N). MR images were segmented and kinematic calculations done with in-house MATLAB software (The MathWorks, Natick, MA). Translation and rotation of the tibia and the tibiofemoral contact area were measured. Statistical analysis treated reconstructed and contralateral knees as independent groups. Reconstructed groups were compared with analysis of covariance using contralateral knees as baseline. P < .05 indicated significance. RESULTS: All kinematic measures in the AM group were similar to contralateral knees. The TT group showed significantly more total tibial rotation than contralateral knees (TT, 8.4° ± 3.9°; contralateral, 2.9° ± 6.8°) (P = .03), whereas the AM group did not (AM, 3.1° ± 5.6°; contralateral, 2.3° ± 5.4°) (P = .36). At knee extension, the tibia was more externally rotated in the TT group than in controls. Medial tibial translation was greater in the TT group than in controls. The AM group showed increased contact area in the lateral compartment compared with controls; no differences were seen in the TT group. CONCLUSIONS: Using an MR-based approach, we found that knee kinematics were better restored with the AM femoral tunnel drilling ACL reconstruction than with the TT femoral tunnel drilling approach, which resulted in increased knee laxity. Our in vivo results support previous cadaveric and clinical studies that have found AM ACL reconstruction to restore anatomy and stability better than the TT approach. However, the clinical significance of increased contact area in the AM group remains unclear. LEVEL OF EVIDENCE: Level III, retrospective comparative study.