Dual Mobility in Total Hip Arthroplasty: Biomechanics, Indications and Complications-Current Concepts.

Dual-mobility (DM) articulations are increasingly utilized to prevent or manage hip instability after total hip arthroplasty (THA). DM cups offer enhanced stability due to the dual articulation resulting in larger jump distance and greater range of motion before impingement. Improvement in design features and biomaterials has contributed to increased interest in dual-mobility articulations due to lower risk of complications compared to their historic rates. The incidence of implant-specific complications like intra-prosthetic dislocation (IPD) and wear has reduced with newer-generation implants. DM THAs are used in primary THA in patients with high risk for dislocation, e.g. neuromuscular disorder, femoral neck fracture, spinopelvic deformity, etc. They offer an attractive alternative option to constrained liner for treatment of hip instability in revision THA. The medium- to short-term results with DM THA have been encouraging in primary and revision THA. However, there are concerns of fretting, corrosion and long-term survivorship with DM THA. Hence, longer-term studies and surveillance are required for the safe use of DM THA in clinical practice.

Dual-Mobility Articulations in Femoral Neck Fractures: A Systematic Review of the Literature and Meta-analysis of the Outcomes.

INTRODUCTION: Femoral neck fractures have been traditionally managed with hemiarthroplasty (HA) or conventional total hip arthroplasty (CTHA). There has been recent interest in using dual-mobility components (DMC) in total hip arthroplasty for patients with femoral neck fractures to provide increased stability and decrease the need for future revision. METHODS: We conducted a systematic review of the literature reporting on the use of DMC in the management of femoral neck fractures in geriatric patients. We included studies in which DMC were used alone and studies that included a comparison to total hip arthroplasty or HA. The outcomes of interest were postoperative dislocation, revision, and revision surgery rates. Two separate subgroup analyses were conducted. For the comparative studies, we analyzed the differences in outcomes using a random-effects model of relative risks. For the noncomparative studies, we estimated the cumulative incidence of the different outcomes. RESULTS: Eighteen studies met the inclusion criteria and were included in our analysis. Eleven noncomparative studies showed a cumulative incidence of dislocation to be 1.2% (95% confidence interval = 0.3% to 2.7%) when DMC were used alone. Subgroup analyses of the seven comparative studies yielded a relative risk of dislocation using DMC was 59% less than HA and 83% less than CTHA. DMC also compared favorably in terms of revision surgery and revision rates to HA. There was insufficient quality evidence to comment on revision surgery and revision rates when compared with CTHA in comparative studies, but among the noncomparative studies, there was a low rate of revision and revision surgery. CONCLUSIONS: Our study revealed overall lower risk of dislocation using DMC compared with both CTHA and HA. There were also lower revision and revision surgery rates when DMC were used compared with HA. Further studies are required to elucidate cost-effectiveness and long-term outcomes of DMC in these scenarios. LEVEL OF EVIDENCE: Level III-meta-analysis.

Isolated Acetabuloplasty and Labral Repair for Combined-Type Femoroacetabular Impingement: Are We Doing Too Much?

PURPOSE: To evaluate patient outcomes after isolated arthroscopic volumetric acetabular osteoplasty and labral repair for the treatment of patients with combined femoroacetabular impingement (FAI) lesions. METHODS: A review of a prospectively collected registry identified 86 patients (106 hips) with an average age of 38.1 years (range, 17-59 years) with combined-type FAI that underwent isolated acetabular osteoplasty and labral repair. Preoperative α-angle, degree of radiographic degenerative changes, and presence of a crossover sign were recorded. Clinical outcomes were assessed with the modified Harris Hip Score (mHHS), International Hip Outcome Tool-12 (iHOT-12), Hip Outcome Score Sport-Specific Subscale (HOS-SSS), and patient satisfaction score (out of 10) at a minimum 2-year follow-up. RESULTS: Clinical follow-up was obtained at a mean follow-up of 37.2 months (range, 27.9-79.2 months). Patients with Tönnis grade 0 and I findings had significantly higher mHHS (83.5 vs 71.5, P = .01), HOS-SSS (81.3 vs 59.9, P = .02), and iHOT-12 scores (71.1 vs 58.8, P = .04) compared to patients with Tonnis grade II changes. However, patient satisfaction scores (8.0 vs 7.2, P = .45) were no different. No significant difference was noted between unilateral and bilateral hip patient outcome scores. Patient age and preoperative α-angles did not correlate with any outcome scores (all R2 <0.05). There were no cases of revision surgery or progression to arthroplasty. CONCLUSIONS: Isolated acetabular decompression may adequately address the underlying impingement in combined-type FAI while avoiding the risks associated with femoral-sided decompression. Good to excellent patient-reported outcomes and satisfaction scores were noted with significantly higher scores in patients with minimal arthritic change. Patient age and preoperative α-angle had less effect on postoperative outcomes. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Symptomatic flexion instability in posterior stabilized primary total knee arthroplasty.

Flexion instability in posterior-stabilized total knee arthroplasty is a relatively uncommon but distinct problem that is often underdiagnosed and may require surgical management. This retrospective study evaluated the authors' management strategy and assessed the results of revision surgery. The authors identified 19 knees that underwent revision for isolated flexion instability after primary posterior-stabilized total knee arthroplasty. All patients had typical symptoms and signs of flexion instability, which include diffuse pain, especially when negotiating stairs, a sense of instability without giving way, recurrent joint effusions, and diffuse periarticular tenderness. Knee Society scores were used to assess pain and function. Complete revision was performed in 11 knees, femoral revision with a thicker insert was performed in 1 knee, and isolated tibial polyethylene insert exchange was performed in 7 knees. Postoperatively, all patients reported improvement in instability symptoms and signs associated with improvement in mean Knee Society scores. Revision surgery with careful gap balancing is successful in the management of isolated flexion instability in posterior-stabilized total knee arthroplasty. Isolated tibial polyethylene insert exchange may have a role in selected patients where component malalignment and malrotation is ruled out and a thicker and/or semiconstrained insert can be used, while limiting the resultant flexion contracture to less than 5°.

Clinical and Biomechanical Evaluation of an All-Arthroscopic Suprapectoral Biceps Tenodesis.

BACKGROUND: Pathology of the long head of the biceps (LHB) is a well-recognized cause of shoulder pain in the adult population and can be managed surgically with tenotomy or tenodesis. PURPOSE: To compare the biomechanical strength of an all-arthroscopic biceps tenodesis technique that places the LHB distal to the bicipital groove in the suprapectoral region with a more traditional mini-open subpectoral tenodesis. This study also evaluates the clinical outcomes of patients who underwent biceps tenodesis using the all-arthroscopic technique. STUDY DESIGN: Controlled laboratory study and case series; Level of evidence, 4. METHODS: For the biomechanical evaluation of the all-arthroscopic biceps tenodesis technique, in which the biceps tendon is secured to the suprapectoral region distal to the bicipital groove with an interference screw, 14 fresh-frozen human cadaveric shoulders (7 matched pairs) were used to compare load to failure and displacement at peak load with a traditional open subpectoral location. For the clinical evaluation, 49 consecutive patients (51 shoulders) with a mean follow-up of 2.4 years who underwent an all-arthroscopic biceps tenodesis were evaluated using the American Shoulder and Elbow Surgeons (ASES) score preoperatively and at last follow-up, as well as the University of California, Los Angeles (UCLA) Shoulder Score at last follow-up. RESULTS: On biomechanical evaluation, there was no significant difference in peak failure load, displacement at peak load, or displacement after cyclic testing between the arthroscopic suprapectoral and mini-open subpectoral groups. In the clinical evaluation, the mean preoperative ASES score was 65.4, compared with 87.1 at last follow-up. The mean UCLA score at last follow-up was 30.2. Forty-eight (94.1%) patients reported satisfaction with the surgery. In subgroup analysis comparing patients who had a rotator cuff repair or labral repair at time of tenodesis with patients who did not have either of these procedures, there were no significant differences in UCLA or ASES scores. CONCLUSION: The excellent biomechanical strength as well as the high rate of satisfaction after surgery and high ASES and UCLA postoperative scores make this technique a novel option for treatment of biceps tendon pathology.

Time and Cost of Diagnosis for Symptomatic Femoroacetabular Impingement.

BACKGROUND: Femoroacetabular impingement (FAI) and labral tears are common causes of hip pain that are often not promptly or properly diagnosed. To our knowledge, no reports have defined the time and cost of diagnosis of labral tears associated with FAI. HYPOTHESIS: Patients with labral tears associated with FAI undergo extraneous diagnostic testing and pain and incur a significant amount of health care costs before they receive appropriate surgical management for their pathology. STUDY DESIGN: Economic and decision analysis; Level of evidence, 4. METHODS: A total of 78 patients diagnosed with symptomatic FAI were surveyed. A standardized questionnaire asked patients about time to diagnosis, symptoms, health care providers visited, imaging tests, and treatments prior to diagnosis. Costs were calculated based on 2012 national Medicare data. RESULTS: Patients in the cohort saw an average of 4.0 health care providers, had an average of 3.4 diagnostic imaging tests, and tried an average of 3.1 treatments prior to diagnosis. The average total amount spent per patient prior to diagnosis was US$2456.97. The calculated minimum cost of diagnosis, including a visit to an orthopaedic surgeon as well as an anteroposterior pelvis and lateral hip radiograph and 1 magnetic resonance arthrogram, was US$690.62. The average duration between onset of symptoms and diagnosis of labral tear was 32.0 months. CONCLUSION: The average amount of health care dollars spent per patient prior to receiving a diagnosis of acetabular labral tear was US$1766.35 higher than the calculated minimum cost. This figure is based on Medicare payment amounts, which may significantly underestimate the actual charges at many hospitals, thereby increasing the total cost of diagnosis. CLINICAL RELEVANCE: The costs and pain associated with this time, along with the potential long-term degradation of the hip joint, make it important for all health care professionals to recognize and appropriately manage or refer the patient.

Does the direct anterior approach in THA offer faster rehabilitation and comparable safety to the posterior approach?

BACKGROUND: Newer surgical approaches to THA, such as the direct anterior approach, may influence a patient's time to recovery, but it is important to make sure that these approaches do not compromise reconstructive safety or accuracy. QUESTIONS/PURPOSES: We compared the direct anterior approach and conventional posterior approach in terms of (1) recovery of hip function after primary THA, (2) general health outcomes, (3) operative time and surgical complications, and (4) accuracy of component placement. METHODS: In this prospective, comparative, nonrandomized study of 120 patients (60 direct anterior THA, 60 posterior THAs), we assessed functional recovery using the VAS pain score, timed up and go (TUG) test, motor component of the Functional Independence Measure™ (M-FIM™), UCLA activity score, Harris hip score, and patient-maintained subjective milestone diary and general health outcome using SF-12 scores. Operative time, complications, and component placement were also compared. RESULTS: Functional recovery was faster in patients with the direct anterior approach on the basis of TUG and M-FIM™ up to 2 weeks; no differences were found in terms of the other metrics we used, and no differences were observed between groups beyond 6 weeks. General health outcomes, operative time, and complications were similar between groups. No clinically important differences were observed in terms of implant alignment. CONCLUSIONS: We observed very modest functional advantages early in recovery after direct anterior THA compared to posterior-approach THA. Randomized trials are needed to validate these findings, and these findings may not generalize well to lower-volume practice settings or to surgeons earlier in the learning curve of direct anterior THA.

All-arthroscopic iliotibial band autograft harvesting and labral reconstruction technique.

The labrum is essential for stability, movement, and prevention of arthritis in the hip. In cases of labral damage where repair of a labral tear is not possible, reconstruction can be a useful alternative. Several different autografts have been used, including the iliotibial band (ITB), the ligamentum teres capitis, and the gracilis tendon. Authors have reported both open and arthroscopic techniques for reconstruction with good preliminary results. However, an all-arthroscopic labral reconstruction technique including the graft harvest and reconstruction portions of a labral reconstruction procedure using an ITB autograft has not been previously described. We describe a technique for an all-arthroscopic labral reconstruction performed using a novel method for arthroscopic harvest of the ITB. The decreased invasiveness of our described technique for labral reconstruction may potentially minimize scarring, bodily disfigurement, infection, and postoperative pain associated with the graft harvesting incision.

Radiographic results of an accelerometer-based, handheld surgical navigation system for the tibial resection in total knee arthroplasty.

In total knee arthroplasty (TKA), intramedullary and extramedullary tibial alignment guides are not proven to be highly accurate in obtaining alignment perpendicular to the mechanical axis in the coronal plane. The objective of this study was to determine the accuracy of an accelerometer-based, handheld surgical navigation system in obtaining a postoperative tibial component alignment within 2° of the intraoperative goal in both the coronal and sagittal planes. A total of 151 TKAs were performed by 2 surgeons using a handheld surgical navigation system to perform the tibial resection. Postoperatively, standing anteroposterior hip-to-ankle radiographs and lateral knee-to-ankle radiographs were performed to determine the varus/valgus alignment and the posterior slope of the tibial components relative to the mechanical axis in both the coronal and sagittal planes. Findings showed that 95.3% of the tibial components were placed within 2° of the intraoperative goal in the coronal plane and 96.1% of the components were placed within 2° of the intraoperative goal in the sagittal plane. Overall, mean postoperative lower-extremity alignment was -0.3°±2.1°, with 97% of patients having an alignment within 3° of a neutral mechanical axis. The handheld surgical navigation system improves the accuracy of the tibial resection and subsequent tibial component alignment in TKA. It is able to combine the accuracy of computer-assisted surgery systems with the ease of use and familiarity of conventional, extramedullary alignment systems, and the ability to adjust both the coronal and sagittal alignments intraoperatively may prove clinically useful in TKA.

Primary hip arthroplasty with 28-mm Metasul articulation.

This follow-up study reports on 69 patients at mean 13 years with total hip arthroplasty using 28-mm Metasul (Zimmer, Winterthur, Switzerland) metal-on-metal articulation. These results are not transferable to large-diameter head metal-on-metal articulations. Four new revisions, 3 for disassociation of the liner and 1 for mechanical loosening of the acetabulum, occurred since the previous report of mean 7.3 years. The prevalent cause of late revision is disassociation, which suggests a high frictional torque or impingement in these articulation surfaces. No revision was done for osteolysis. Overall, of the original 127 hips, 116 (91%) were known to have maintained their original components.

A comparison of surgeon estimation and computed tomographic measurement of femoral component anteversion in cementless total hip arthroplasty.

BACKGROUND: The intraoperative estimation of the anteversion of the femoral component of a total hip arthroplasty is generally made by the surgeon's visual assessment of the stem position relative to the condylar plane of the femur. Although the generally accepted range of intended anteversion is between 10 degrees and 20 degrees, we suspected that achieving this range of anteversion consistently during cementless implantation of the femoral component was more difficult than previously thought. METHODS: We prospectively evaluated the accuracy of femoral component anteversion in 109 consecutive total hip arthroplasties (ninety-nine patients), in which we implanted the femoral component without cement. In all hips, we measured femoral stem anteversion postoperatively with three-dimensional computed tomography reconstruction of the femur, using both the distal femoral epicondyles and the posterior femoral condyles to determine the femoral diaphyseal plane. The bias and precision of the measurements were calculated. RESULTS: The surgeon's estimate of femoral stem anteversion was a mean (and standard deviation) of 9.6 degrees +/- 7.2 degrees (range, -8 degrees to 28 degrees). The anteversion of the stem measured by computed tomography was a mean of 10.2 degrees +/- 7.5 degrees (range, -8.6 degrees to 27.1 degrees) (p = 0.324). The correlation coefficient between the surgeon's estimate and the computed tomographic measurement was 0.688; the intraclass coefficient was 0.801. Anteversion measured by computed tomography found that forty-nine stems (45%) were between 10 degrees and 20 degrees of anteversion; forty-three stems (39%) were between 0 degree and 9 degrees of femoral anteversion; eight stems (7%) were in anteversion of >20 degrees; and nine stems (8%) were in retroversion. CONCLUSIONS: The surgeon's estimation of the anteversion of the cementless femoral stem has poor precision and is often not within the intended range of 10 degrees to 20 degrees of anteversion. The implications of this finding increase the importance of achieving a safe range of motion by evaluating the combined anteversion of the stem and the cup.

Precision surgery.

Accurate component placement in joint replacement cannot be overemphasized; despite many re-engineering efforts over the past 3 decades, failure rates at 10 years for total hip arthroplasty (THA) and total knee arthroplasty (TKA) remain constant. Intraoperative decisions with joint replacement have been facilitated with manual instrumentation and are affected by the surgeon's intuition, instinct, and experience. Current technology allows the development and use of high-tech instrumentation, which, irrespective of surgeon-dependent variables, gives intraoperative quantitative information on which precise placement of hip and knee components can be done. Component placement is the single most important technical maneuver the surgeon accomplishes to prevent mechanical complications, which will nearly eliminate outliers from very good and excellent results and revision as a consequence of technical errors; computer navigation has almost made it possible. In knees it gives precise component placement in the coronal and sagittal planes, and in hips it particularly improves acetabular component position by numerical control of inclination, anteversion, and most importantly center of rotation. Precision is enhanced even more when computer navigation is elevated to the next level, which is robotic guidance. The preoperative plan set by the surgeon is executed by the robotic tool while the surgeon manually controls the robotic arm. Bone preparation cannot exceed the boundaries the surgeon has set, as the surgeon's manual force will stop the robot and the error cannot be made. Robotic surgery has progressed in the unicompartmental knee, and this innovation is in the final stages of development in THA.