Accuracy of radiographic projections to guide cephalic screw position in pertrochanteric fracture: a cadaveric study.

PURPOSE: The aim of this study was to evaluate the relationship between the Löwenstein Lateral view and the True Lateral view for the positioning of the cephalic hip screw, through a cadaveric study. MATERIALS AND METHODS: We placed two Kirschner wires in eight femur specimens using an Antero-Posterior view, Löwenstein Lateral view and True Lateral view. The distances between the Kirschner wires and the anterior, posterior, superior and inferior cortex were measured in all projections. The head of the femur was then sectioned, and the same macroscopic distances were measured. Finally, we could calculate the accuracy of the two radiographic lateral projections. RESULTS: When the Kirschner wire was placed in the center of the head using the Antero-Posterior and the True Lateral view, the accuracy of Antero-Posterior view was 0.9705 while the accuracy of True Lateral view and Löwenstein Lateral view was 1.1479 and 1.1584, respectively. When the Kirschner wire was placed superior on the Antero-Posterior and centrally on the True Lateral view, the accuracy of Antero-Posterior view was 0.9930 while the accuracy of True Lateral view and Löwenstein Lateral view was 1.1159 and 0.7224, respectively. CONCLUSION: When the Kirschner wire was positioned proximal in Antero-Posterior view and central in True Lateral view, only the True Lateral view showed high accuracy.

All-Inside Posterior Cruciate Ligament Reconstruction Using Autologous Quadriceps Tendon-Bone Block.

Posterior cruciate ligament ruptures account for nearly 20% of knee ligament lesions. These may be either isolated or occur as part of multiligament injuries. In most of the cases, conservative treatment is recommended, but when operative treatment is required, this is technically demanding. Several posterior cruciate ligament reconstructive techniques have been described, but some concerns still remain regarding graft choice, tunnels position, visualization of the posterior compartment and graft fixation. We describe an arthroscopic all-inside technique using a single-bundle autologous quadriceps tendon with patellar bone block.

Functional Outcomes of Anterior-Based Muscle Sparing Approach Compared to Direct Lateral Approach for Total HIP Arthroplasty Following Acute Femoral Neck Fractures.

Introduction: Total hip arthroplasty (THA) performed for femoral neck fractures (FNFs) is becoming a more frequent treatment in the active elderly population. Since there is limited research available presenting clinical outcomes after THA using the anterior-based muscle sparing (ABMS) approach, the aim of this study was to compare this surgical approach to the direct lateral (DL) approach in patients treated by THA for FNFs. Materials and Methods: We retrospectively reviewed the data prospectively collected as a part of our "Hip Fracture Unit" and included 163 patients who underwent THA from January 2016 to January 2019 for acute displaced FNFs. Results: A total of 132 patients who completed a minimum 2-years follow up (69 in the ABMS group and 63 in DL group) were included. The ABMS group demonstrated significantly shorter time to reach milestone for hospital discharge (1.5 Days vs 2.1 days, P = .018), while no statistically significant differences were detected in peri-operative complications. At 3 months, the timed up and go test, the Harris Hip Score (HHS) and the Oxford ip Score (OHS) were significantly better (P = .024, .032 and .034, respectively) in the ABMS group compared to the DL group. No differences were found in functional outcomes (HHS and OHS) nor in complication rate at 6, 12 and 24 months. Discussion: This is one of the first studies to analyze functional results of THA performed for FNFs through an ABMS approach. Results are in line with those already present in the Literature. Conclusion: ABMS approach allows earlier mobilization and better early functional outcomes, compared to DL approach, in patients undergoing THA for acute displaced FNF. No differences are found after 6 months in functional results and complications rate.

How reproducible are clinical measurements in robotic knee surgery?

PURPOSE: Robotic-assisted surgery has been recently introduced to improve biomechanical restoration, and thus better clinical and functional outcomes, after knee joint arthroplasty operations. Robotic-assisted uni-compartmental knee arthroplasty (UKA) aims indeed to improve surgical bone resection and alignment accuracy, optimized component positioning and knee balancing, relying on a series of calibration measurements performed during the surgery. These advantages focus therefore on improving the reproducibility of UKA surgeries, reducing (if not eliminating) eventual differences among high- and low-volume surgeons. The purpose of this study is to investigate and quantify the reproducibility of in-vivo measurements performed with a robotic system: the intra- and inter-observer variability of a series of measurements was therefore analyzed and compared among differently experienced operators. METHODS: Five patients were analyzed and underwent robotic-assisted UKA using a semi-active robotic system. Three different observers with different experience levels were involved to independently perform the measurements of two parameters of the preoperative knee (Hip-Knee-Ankle angle [HKAa], Internal-External Rotation) at different degrees of knee flexion. Inter-observer and intra-observer comparisons were performed. RESULTS: The average variability in the measurements obtained from the intra-observer and inter-observer comparisons were always < 0.68° for HKAa and < 2.59° for internal-external rotation, and the ICCs showed excellent agreement (> 0.75) for most cases and good agreement (> 0.60) in the remaining ones. CONCLUSION: This study demonstrated high reproducibility of the measurements obtainable in clinical environment with the robotic system. The inter-observer results furthermore showed that the level of confidence with the robotic system is not significantly influencing the measurement.

The use of posteromedial portal for arthroscopic treatment of synovial chondromatosis of the knee: a case report.

BACKGROUND: The synovial chondromatosis is an uncommon proliferative metaplastic process of the synovial cells that can develop in any synovial joint. An isolated primary chondromatosis of the posterior compartment of the knee is uncommon and few cases are reported in literature. Our purpose is to describe a rare case of primary chondromatosis of the knee posterior compartment and report the arthroscopic loose bodies excision through a difficult posteromedial portal, avoiding the use of the accessory posterior portal, most commonly reported for approaching this disease. CASE PRESENTATION: We report a rare case of a 35-year-old Caucasian male patient with diagnosis of chondromatosis of the posterior knee compartment. The radiographs showed multiple loose bodies of the posterior compartment. The MRI revealed minimal synovial hypertrophy areas, multiple osteophytes in the intercondylar notch, and loose bodies in the posteromedial compartment. The CT allowed us to assess the bony structures, the morphology of the intercondylar notch, and the presence osteophytes of the medial and lateral femoral condyles. The CT images were crucial to plan how to reach the posterior compartments of the knee through a trans-notch passage. The patient underwent arthroscopic surgery using anteromedial, anterolateral, and posteromedial portals. The tunneling through the intercondylar osteophytes was performed to allow the arthroscope to pass trans-notch. To avoid additional accessory posterior portals, we used a 70° arthroscope to better explore the posterior knee compartment. The cartilage-like bodies were removed and synovectomy of the inflamed areas was performed. The clinical and radiological follow-up was 12 months and the patient showed excellent clinical outcomes, returning to his activities of daily living and sport activity. CONCLUSION: Our case report highlights the importance of the arthroscopic approach to treat synovial chondromatosis, despite the involvement of the posterior compartment of the knee. An optimal preoperative imaging allows to plan for the proper surgical procedure even in patients with severe osteoarthritis. Moreover, the adoption of an intercondylar notch tunneling and a 70° arthroscope can help surgeons to better explore the posterior knee compartment, avoiding an accessory posterior trans-septal portal. Therefore, a synovectomy of the inflamed foci may be useful to prevent recurrence.

Controversies in ACL revision surgery: Italian expert group consensus and state of the art.

BACKGROUND: Revision ACL reconstruction is a complex topic with many controversies and not-easy-to-make decisions. The authors' aim is to provide some feasible advice that can be applied in daily clinical practice with the goal of facilitating the decision-making process and improving the outcomes of patients subjected to revision ACL reconstruction. METHODS: A national survey with seven questions about the most controversial topics in revision ACL reconstruction was emailed to members of two societies: SIOT and SIAGASCOT. The participants' answers were collected, the most recent literature was analyzed, and a consensus was created by the authors, according to their long-term surgical experience. CONCLUSIONS: The decision-making process in revision ACL reconstruction starts with a standardized imaging protocol (weight-bearing radiographs, CT scan, and MRI). One-stage surgery is indicated in almost all cases (exceptions are severe tunnel enlargement and infection), while the choice of graft depends on the previously used graft and the dimensions of the tunnels, with better clinical outcomes obtained for autografts. Additional procedures such as lateral extra-articular tenodesis in high-grade pivot-shift knees, biplanar HTO in the case of severe coronal malalignment, and meniscal suture improve the clinical outcome and should be considered case by case. LEVEL OF EVIDENCE: V (Expert opinion).

Robotic-Assisted Unicompartmental Knee Arthroplasty Reduces Components' Positioning Differences among High- and Low-Volume Surgeons.

Robotic-assisted medial unicompartmental knee arthroplasty (mUKA) has been introduced to improve accuracy in implant positioning and limb alignment, overcoming the reported high failure rates of conventional UKA. Indeed, mUKA is a technically challenging procedure strongly related to surgeons' skills and expertise. The purpose of this study was to evaluate the likelihood of robotic-assisted surgery in reducing the variability of coronal and sagittal component positioning between high- and low-volume surgeons. We evaluated a prospective cohort of 161 robotic mUKA implanted between May 2018 and December 2019 at two high-volume robotic centers. Patients were divided into two groups: patients operated by "high-volume" (group A) or "low-volume" (group B) surgeons. We recorded intraoperative lower-limb alignment, component positioning, and surgical timing. Postoperatively, every patient underwent a radiographical protocol to assess coronal and sagittal femoral/tibial component alignment. Range of motion and other clinical outcomes were assessed pre- and 12 months postoperatively by using oxford knee score, forgotten joint score, and visual analog scale. Of 161 recruited knees, 149 (A: 101; B: 48) were available for radiographic analysis at 1 month, and clinical evaluation at 12 months. No clinical difference neither difference in mechanical alignment nor coronal/sagittal component positioning were found (p > 0.05). A significant difference was recorded in surgical timing (A: 57 minutes; B: 86 minutes; p < 0.05). No superficial or deep infections or other major complications have been developed during the follow-up. Robotics surgery in mUKA confirmed its value in improving the reproducibility of such technical procedure, with satisfactory clinical outcomes. Moreover, it almost eliminates any possible differences in component positioning, and lower limb alignment among low-and high- volume knee surgeons.

The New Challenge in the Management of Proximal Femur Fractures during SARS Cov-2 outbreak.

The aim of this study is to evaluate how the spread of Sars-Cov-2 has changed the epidemiology of proximal femur fractures in two major trauma centers in Italy, understanding the workload and the best allocation of the resources for the orthopedics department in such an emergency situation. The rate of patients from January 2019 to April 2020 hospitalized with femoral neck fractures (group A) and trochanteric fractures (group B) were recorded. Demographic data, timing of surgical treatment and the length of stay were recorded. Data show that the number of proximal femur fractures has remained unchanged in the COVID and pre-COVID era (ranging from an average of 91.14/month in the pre-COVID era to 76/month in March and 80/month in April). In our trauma centers, the rate of patients operated on within 48 hours has remained stable (78.19% vs 77.92%), while the length of stay has decreased during the COVID period (8.9 days vs 6.5 days in March and 6.8 days in April). Proximal femur fractures, even during the COVID period, are a constant issue and a new challenge for the healthcare system. The main goals of management are to preserve patients from viral infection, to provide early surgical treatment and fast track protocol for discharge.

Proximal femoral replacement: A salvage treatment of cephalomedullary nails' mechanical failures in the elderly population.

BACKGROUND: The use of proximal femoral replacements (PFR) has been recently described for catastrophic internal fixation failures. PFR is an attractive treatment option because it is technically straightforward and allows for immediate mobilization of the patient. The aim of the study was to determine the survivorship, functional outcome and complications' rate in a group of elderly patients who underwent proximal femoral replacement as a salvage treatment after femur cephalomedullary nails' mechanical failures. METHODS: We evaluated 21 patients who underwent salvage of a failed cephalomedullary nail by using a single design PFR at our institution between 2014-2017. A cemented stem was used in all cases. Radiographs were assessed for fractures, sign of loosening, presence of heterotopic ossification and leg length discrepancy. Functional evaluation was performed through Harris Hip Score (HHS), FIM™ and Time Up and Go test (TUG). Kaplan-Meier estimator was used to determine the overall implants' survival. RESULTS: The average age at the time of surgery was 83years. The mean follow-up was 3.1years. We recorded 3 dislocations of which 2 required a revision. No case of septic or aseptic failure was reported. Two patients died respectively at 11 and 14 months after surgery. At the last follow-up the mean HHS, FIM™, and the TUG improved significantly (p<0.05). CONCLUSION: Immediate weight bearing, good functional outcomes, low complications' and one-year mortality rate make the proximal femur replacement with megaprostheses a potential first line treatment of intertrochanteric/subtrochanteric fixations' failures among elderly, osteoporotic, frail patients. Dislocation is the most common complication to bear in mind within the first six months after surgery.

Arthroscopic confirmation of femoral button deployment avoids post-operative X-ray in ACL reconstruction.

BACKGROUND: Anterior cruciate ligament reconstruction (ACLR) with cortical fixation adjustable-loop devices are associated with high potential risk of button malpositioning or interposition of the soft tissue between lateral femoral cortex and the button. Surgeons usually use X-rays to check and avoid button malposition and soft tissue interposition. Arthroscopic visualization of button position through the lateral gutter has been described. With this technique, it is possible for identification and correction of femoral button malalignment in the setting of soft tissue interposition and it could avoid the use of post-operative X-ray. METHODS: A total of 193 ACLR were included and patients were randomized into two groups. The first series (Group A) of 112 patients who sustained an ACLR with post-operative X-ray to assess the position of the femoral button and the second series (Group B) of 81 patients who sustained an ACLR with an arthroscopic exploration of the button followed by post-operative X-ray. RESULTS: On the post-operative radiographs, tissue interposition between the button and femoral cortex was found in nine cases of 112 in Group A (8%) and in zero case of 81 in Group B (0%). In six cases (7,4%) in Group B, there was a soft tissue interposition between the button and femoral cortex as visualized by arthroscopic confirmation and before post-operative X-ray; in all these cases, the soft tissue was removed, and the button was in contact with the bone in all X-ray made in the Group B. CONCLUSIONS: This technique allows for identification and correction of femoral button malalignment in the setting of soft tissue interposition and reduces the use of post-operative X-ray.

Timing for Safe Return to Sport after Medial Patellofemoral Ligament Reconstruction: The Role of a Functional Test Battery.

The purpose of this article was to analyze clinical and functional results after medial patellofemoral ligament (MPFL) reconstruction and to establish if a computer-assisted physical test battery could determine a "safe timing" to return to sport. We hypothesized that "time-based" criteria to declare safe return to sport could not be reliable to predict functional recover. Fifty-eight young athletic patients were selected after isolated reconstruction of MPFL. The minimum follow-up was 8 months. All the patients were evaluated subjectively with Kujala and Short Form 36 (SF-36) scores and objectively through a standardized computer-assisted physical battery of seven tests (Back in Action, Corehab). No patient was lost at the end point of follow-up and no recurrence of patellar dislocation was reported. At 8 months, 31 patients (53.4%) returned to sport at preoperative levels, and 23 (39.6%) participated in sports at lower levels. The subjective evaluation reported an increase of Kujala (60-92.7) and SF-36 score (28.6/25.4-52.2/53.6). At computer-assisted objective assessment, only 23 patients (39.6%) fulfilled the criteria for safe return to sport, while 31 (53.4%) got an insufficient outcome and 4 (6.9%) failed to complete the test. From our data, clinical scores after MPFL reconstruction provide only little insight into return to sport. The introduction of a computer-assisted objective analysis in the decision-making process for proper return to sport is necessary to evaluate functional recovery and dynamic knee stability.

"Anterolateral" approach to the hip: a systematic review of the correct definition of terms.

PURPOSE: The Watson-Jones interval plane between tensor fascia lata (TFL) and the gluteus medius (GM) has come back into fashion in the past few years - Röttinger described the anterolateral minimal invasive approach (ALMI) for use in total hip replacement, in which the standard Watson-Jones interval was used, but with a completely intermuscular plane. However, the term anterolateral is often still utilised to describe intramuscular approaches in which the GM was violated, thus creating a potential misunderstanding in the literature. Accordingly, we have designed a study to answer the following questions: (1) are there articles in the recent literature that use the term "anterolateral" to describe different approaches; (2) which would be the correct description of the anterolateral approach? METHODS: We did a systematic review of the literature based on PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, to look for peer reviewed papers of any evidence level focusing on the definition of anterolateral approach; MEDLINE and EMBASE were searched. RESULTS: 73 manuscripts met the criteria of the systematic search. 53 papers (72.6%) reported the term anterolateral approach to describe a complete intermuscular approach between the interval between GM and TFL. Nonetheless, in the remaining 20 papers (27.4%) the term anterolateral was used to describe intramuscular approaches in which the gluteus medius was violated. CONCLUSION: In about 1 out of 4 papers in the recent literature, the term anterolateral was utilised to describe approaches that are completely different both in terms of anatomy and function.

Precision and accuracy of robot-assisted technology with simplified express femoral workflow in measuring leg length and offset in total hip arthroplasty.

BACKGROUND: Semi-active robot-assisted total hip arthroplasty (THA) has two options to measure the leg length discrepancy (LLD) and combined offset (CO), the 'enhanced' femoral workflow and the so-called 'express' simplified workflow. The purpose of this study was to determine the precision and accuracy of intraoperative LLD and CO measurement with express workflow robotic THA. METHODS: Between February 2018 and December 2019, 30 patients underwent an express workflow robot-assisted primary THA for intraoperative LLD and CO measurements. Postoperative radiographs were used for LLD and CO measurement. In order to examine the accuracy of the robotic system assessment, the absolute difference between the robotic assessments and radiographic evaluations was calculated. RESULTS: Intraoperative robotic measurements reported a mean error of 0.2-0.6 mm for each registration, with no significant difference between them (p = 0.311). The average absolute discrepancies between the robotic and radiographic assessments in the LLD and CO measurements were 1.3 ± 1.5 mm (p = 0.17) and 1.1 ± 0.9 mm (p = 0.11), respectively, while the Pearson's correlation coefficients were 0.69 and 0.71. CONCLUSIONS: An external marker without a femoral array inserted into a screw positioned in the greater trochanter would be an easier and faster method to measure LLD and CO. Our study showed that the measured values of LLD and CO obtained by intraoperative express workflow robot-assisted THA system were precise and accurate.

Partial rupture of anterior cruciate ligament: preliminary experience of selective reconstruction.

BACKGROUND: Partial lesions of the anterior cruciate ligament (ACL) are more common than is generally thought, accounting for about 10-12% of ACL injuries. Selective reconstruction may be considered as an option in isolated bundle rupture. The purpose of this study is to evaluate both subjective and objective clinical results, as well as functional recovery time, after selective arthroscopic single-bundle reconstruction in a consecutive series of patients affected by partial ACL rupture. MATERIALS AND METHODS: Thirty-six patients undergoing selective reconstruction of a single ACL bundle were retrospectively evaluated from a series of 354 ACL reconstructions performed over a 3-year period. Although the suspicion of partial lesions was present at clinical and magnetic resonance imaging (MRI) evaluation, final diagnosis was obtained during arthroscopy. All patients were operated using the same technique and type of fixation, and undergoing the same functional recovery protocol. RESULTS: Mean follow-up was 64 months (48-84 months). All patients but one achieved good functional recovery and returned to their sports within a mean period of 6.1 months. A single patient complained of postoperative instability 1 year after the index operation and needed further surgery. No complications were recorded. CONCLUSIONS: Selective reconstruction of partial ACL injury is a method to bear in mind because it offers quick functional recovery. Specific technical and diagnostic steps should be performed and discussed with patients preoperatively. LEVEL OF EVIDENCE: Level 4, retrospective study.

Patients Following Revision Total Hip Arthroplasty With Modular Dual Mobility Components and Cobalt-Chromium Inner Metal Head are at Risk of Increased Serum Metal Ion Levels.

BACKGROUND: Modular dual-mobility (MDM) total hip arthroplasty (THA) is designed with a cobalt-chromium liner inserted into a titanium acetabular component. The purpose of this study is to investigate the potential risks for fretting corrosion at this junction, by measuring serum metal ions, after MDM acetabular revision. METHODS: Thirty-seven patients with well-functioning revision THAs participated in a cross-sectional study at mean 5.1 (2-10) years after surgery. All received a trabecular titanium MDM acetabular component. The serum levels of cobalt and chromium were measured using mass spectrometry. RESULTS: The mean values of chromium and cobalt were 2.08 µg/L (95% confidence interval 0.9-3.2, range 0.02-11.8) and 1.99 µg/L (95% confidence interval 0.81-3.17, range 0.07-16.05), respectively. Eleven patients (29, 7%) had ion levels above the normal range, with 6 (16.2%) above 5 µg/L and 5 (13.5%) between 1 and 5 µg/L. A significant correlation was found between an elevated serum metal ion level and University of California Los Angeles score (P = .016). CONCLUSION: We conclude that serum metal level elevation may occur secondary to metal debris resulting from corrosion of the index MDM THA. This potential risk should be included in the decision-making process when dealing with revision arthroplasty in young and active patients.

Bone integration in acetabular revision hip arthroplasty using equine-derived bone grafts: a retrospective study.

PURPOSE: During the last decade, total hip arthroplasty has become a common procedure performed in young patients, as well as elderly ones. This has led to an increase in total hip arthroplasty revisions. Loosening of primary components with associated bone loss represents the major cause of total hip arthroplasty revision. This study evaluates the safety and performance of an enzyme-deantigenic equine-derived bone graft material in acetabular defect reconstruction. METHODS: Records of 55 patients who were treated for Paprosky type II or III acetabular bone defects with arthroplasty revisions using equine-derived bone and followed for an average of 34 months (range from 24 to 48 months) were analyzed. RESULTS: Of the 55 revisions, 49 (89%) were regarded as successful, showing good osteointegration without signs of mobilization. Failures included six cases (11%) of mobilization: five cases of aseptic mobilization (9.1% of revisions, 83% of failures) and one case of septic mobilization (1.9% of revisions, 17% of failures). These results are consistent with those of studies having a similar follow-up period for allografts used in combination with trabecular metal components. CONCLUSIONS: Results of the present study suggest that enzyme-treated equine-derived bone grafts may be a valid alternative to autogenous and homologous bone grafts in total hip arthroplasty revision.

Accelerometer-Based Navigation in Total Knee Arthroplasty for the Management of Extra-Articular Deformity and Retained Femoral Hardware: Analysis of Component Alignment.

Purpose Recent advances in total knee arthroplasty (TKA) include an accelerometer portable system designed to improve component position and alignment. The purpose of this study is to evaluate whether accelerometer navigation system can be a valuable option in complex TKAs for extra-articular deformity of the lower limb or in case of retained femoral hardware. Methods A group of 13 patients underwent TKA with an accelerometer navigation system. Three patients had a tibial extra-articular deformity, six had a femoral extra-articular deformity, and four had an intramedullary nail in the femur. Preoperative and postoperative mechanical axes were measured from full-length lower extremity radiographs to evaluate alignment. The alignment of prosthetic components in the frontal and sagittal planes was determined by postoperative radiographs. Results At 30-days postoperative radiographic check, the hip knee ankle angle was within 2.0° (0 ± 1) of the neutral mechanical axis. The alignment of the tibial component on the frontal plane was 90.0° (range 89-91) and on the sagittal plane 5.0° (range 3-7). The alignment of the femoral component on the frontal plane was 90.0° (range 89-91) and on the sagittal plane 3.0° (range 0-5). Conclusion The alignment of the prosthetic components has been accurate and comparable to other navigation systems in literature without any increase in surgical times. The accelerometer-based navigation system is therefore a useful technique that can be used to optimize TKA alignment in patients with extra-articular deformity or with lower limb hardware, where the intramedullary guides cannot be applied. Level of Evidence This is an observational study without a control group, Level III.

Total Knee Arthroplasty in Patients With Extra-Articular Deformity: Restoration of Mechanical Alignment Using Accelerometer-Based Navigation System.

BACKGROUND: Total knee arthroplasty (TKA) in patients with post-traumatic extra-articular deformity (EAD) is difficult to manage using conventional instrumentation techniques. In this study, we evaluate whether accelerometer navigation system can be a valuable option to make accurate bone resections and restore the neutral mechanical axis in complex TKA patients with EAD. METHODS: From May 2015 to June 2017, 18 consecutive TKA were performed in 18 patients with knee osteoarthritis with associated EAD. An accelerometer-based navigation system was used to guide tibial and femoral resection in the coronal and sagittal plane. Postoperative lower limb alignment in coronal plane and component position in coronal and sagittal plane was measured through full-leg weight-bearing X-ray. Clinical score were recorded using the Knee Society Score at the final follow-up. RESULTS: The mean hip-knee-ankle angle was 0.9° ± 1.4° varus alignment. The coronal alignment of the femoral component was 89.2° ± 1.9°, and the coronal alignment of the tibial component was 89.4° ± 2.1°. The sagittal alignment of the femoral component was 93.2°± 1.9°, and the sagittal alignment of the tibial component was 84.4° ± 3.1°. At the final follow-up, the Knee Society Score was 89 points (range, 82-100), and the functional score was 86.7 points (range, 60-100). No intraoperative and postoperative surgical complications were reported using this technology. CONCLUSION: Accelerometer-based navigation is accurate in achieving neutral mechanical alignment and optimal implant position after TKA in patients with EAD. This system should be considered a valuable option to the more complex technique of computer navigation or robotic surgery.

The anterior-based muscle-sparing approach to the hip: the "other" anterior approach to the hip.

PURPOSE: The purpose of this study was to evaluate safety, efficacy, and learning curves of anterior-based muscle-sparing total hip arthroplasty (ABMS-THA) in the supine position. Furthermore, early functional outcome was evaluated and compared to direct anterior approach (DAA) by measuring surface electromyography (sEMG). METHODS: We present a prospective cohort study of 343 hips. The safety and learning curve were assessed by recording operative time and peri-operative adverse events. For assessment of efficacy, functional and radiological outcomes were evaluated. A selected group of 32 patients have been studied by sEMG and compared to a matched group of 32 patients who received a THA using DAA approach. RESULTS: There was one dislocation (0.3%); two (0.6%) patients had an intra-operative fractures of the greater trochanter; two patients (0.6%) experienced a self-limited femoral nerve palsy. Physical therapy milestones for hospital discharge were reached on an average of 1.7 days. sEMG showed that ABMS and DAA have a similar muscle recruitment pattern and functional recovery after THA. One patient was revised for infection, 16 were lost, and 326 hips were available with a median follow-up of 42 months (range 24-60). The mean Harris Hip Score (HSS) increased from 44.3 to 91.9. Ninety-six percent of the hips had a leg length discrepancy (LLD) < 5 mm. There were no radiological signs of mechanical loosening or osteolysis. CONCLUSIONS: The ABMS approach in the supine position is clinically effective and safe; special advantages include a very low dislocation rate and a great control of LLD.