Dual mobility articulation total hip arthroplasty for displaced neck fracture in elderly with neuromuscular disorder.

PURPOSE: Neuromuscular disease is well known to be at increased risk of complications following hip replacement surgeries. This study is prospectively conducted to investigate clinical performance and survivorship of total hip arthroplasty (THA) using dual mobility articulation in femoral neck fractures of elderly with neuromuscular disease. MATERIALS AND METHODS: We prospectively enrolled 162 patients (162 hips) with displaced femoral neck fracture who gave informed consent for dual mobility articulation THA. Of the 162 patients, 35 patients had neuromuscular disease including cerebral palsy, poliomyelitis, hemiplegia, and Parkinson disease (NM group). The other 127 patients had no history of neuromuscular disease (non-NM group). The mean age was 76.5 years (range, 60 - 95) and female ratio was 71.0% (115/162). Clinical outcomes including Harris hip score (HHS), University of California Los Angles activity (UCLA) score were compared between the two groups. Computed tomography and serial radiographs were obtained after surgery. Postoperative complications and reoperation including revision were recorded. RESULTS: Pain-VAS and all clinical scores of the NM group were comparable to those of the non-NM group. The incidence of dislocation in the NM group did not differ from that in Non-NM group (2/35, 5.7% versus 5/127, 3.9%, p = 0.645). Reoperation was performed in 3 hips (3/35, 8.6%) of the NM group and in 4 hips (4/127, 3.1%) of the non-NM group (p = 0.173). Kaplan-Meier survivorship with an end point of revision for any reason was 97.1% (95% confidence interval [CI], 0.92 to 1.03) in the NM group and 98.4% (95% CI, 0.96 to 1.01) in the non-NM group at 7.3 years after surgery. CONCLUSIONS: In elderly with neuromuscular disease, THA with dual mobility articulation is a reasonable option as a treatment for femoral neck fractures.

Monolithic Dual Mobility Cup Total Hip Arthroplasty Has High Complication Rates With Surgical Fixation in Elderly With Femur Neck Fracture.

BACKGROUND: This study is prospectively conducted to evaluate surgical complications of monolithic dual mobility cup total hip arthroplasty (THA) in elderly patients with fractured neck of the femur. METHODS: Ninety-seven patients (97 hips) with displaced femoral neck fracture who gave informed consent for participation were prospectively enrolled. Their mean age was 76.6 years (range, 60-95 years), and the mean bone mineral density T-score of neck of the femur was -2.8 (range, -1.2 to -5.5). All patients underwent THA with monolithic dual mobility cup, and computed tomography scans were obtained to evaluate radiographic parameters including anteversion, inclination, and loosening of acetabular cups, and periprosthetic acetabular fractures. RESULTS: With regard to cup orientation, mean inclination angle was 40.2° (range, 23.5°-63°) and mean anteversion was 32.6° (range, 7°-66.2°). The proportion of surgical outliers was 10.3% (10/97) in inclination and 35.1% (34/97) in anteversion. Early cup loosening within 2 weeks was detected in 2 hips. Periprosthetic acetabular fractures were identified in 6 hips (6/97, 6.2%). Of the 6 fractures, 5 nondisplaced fractures were healed with conservative management, but 1 fracture with displacement eventually led to cup loosening and the patient underwent revision surgery. Reoperation rate of the monolithic dual mobility cup was 4.1% (4/97). CONCLUSION: The use of the monolithic dual mobility was associated with improper cup fixation and periprosthetic acetabular fractures in the elderly with poor bone stock, although the dual mobility cup lowered the risk of early dislocation after THA.

Periprosthetic femoral fracture as cause of early revision after short stem hip arthroplasty-a multicentric analysis.

BACKGROUND: The objective of this study was to analyze the prevalence and causes of early re-operation after hip replacement surgery using short bone-preserving stems in a large multicentre series. Specifically, we evaluated the clinical features of periprosthetic fractures occurring around short stems. METHODS: A total of 897 patients (1089 hips) who underwent primary total hip arthroplasty or bipolar hemiarthroplasty from January 2011 to February 2015 using short bone-preserving femoral stems were recruited. Mean patient age was 57.4 years (range, 18-97 years), with a male ratio of 49.7% (541/1089). Re-operation for any reason within two years was used as an endpoint. The incidence and clinical characteristics of the periprosthetic femoral fractures were also recorded. Mean follow-up period was 5.1 years (range, 2-7.9 years). RESULTS: Early re-operation for any reason was identified in 16 (1.5%) of 1089 hips. The main reason for re-operation was periprosthetic femoral fracture, which accounted for eight (50%) of the 16 re-operations. The overall incidence of periprosthetic femoral fracture at two years was 1.1% (12/1089). According to the Vancouver classification, two fractures were AG type and the other ten were B1 type. Advanced age, higher American Society of Anesthesiologist grade, femur morphology of Dorr type C, and the use of a calcar-loading stem increased the risk for periprosthetic femoral fracture. CONCLUSION: Periprosthetic femoral fracture was the major reason for re-operation after hip replacement surgery using short bone-preserving stems accounting for 50% (8/16) of re-operations two years post-operatively, but did not seem to deteriorate survivorship of implanted prostheses.

Dislocations after use of dual-mobility cups in cementless primary total hip arthroplasty: prospective multicentre series.

BACKGROUND: The purpose of this study was to investigate the incidence of dislocation and specific complications of the dual-mobility cup. METHODS: The arthroplasties involved 167 hips in 165 patients; 51 hips (30.5%) were in men and 116 (69.4%) were in women. The active articulation E1® dual-mobility cup (Biomet, Warsaw, IN, USA) was used, and the surgical approach was posterolateral in 120 hips and anterolateral in 47 hips. RESULTS: Four (2.3%) dislocations were observed. Mean time of dislocation was 30.5 days post-operatively. Three incomplete reductions occurred during closed reduction. When comparing parameters between dislocation and no-dislocation groups, there were no differences in patient and surgical parameters. However, all dislocations occurred in patients with femoral neck fractures and in the posterolateral approach group. CONCLUSION: The incidence of dislocation in total hip arthroplasty (THA) using a dual-mobility cup was acceptable, and cup diameter of the dislocation group was substantially larger than that of no-dislocation group. Based on clinical outcomes of our study, we conclude that the dual-mobility cup is a reliable option in THA, and further studies are necessary.

Safety and efficacy of bi-annual intra-articular LBSA0103 injections in patients with knee osteoarthritis.

The objective of this study is to assess the safety and efficacy of repeated intra-articular injection of high molecular weight hyaluronic acid (LBSA0103) at a 26-week interval, in patients with osteoarthritis of the knee. The study was an open-label, single arm, multicentre prospective trial conducted in patients with symptomatic knee osteoarthritis. The intervention consisted of two intra-articular injections of LBSA0103, with the second injection performed 26 weeks after the first injection. The primary outcome was the incidence of adverse drug reactions related to each injection. Assessment of efficacy of repeated injections in terms of maintenance of pain relief was a secondary objective of this study. Of the 185 patients screened, 174 patients received the first injection and 153 patients received both injections of LBSA0103. Nine adverse drug reactions occurred in seven patients (4.02%) after the first injection, while only one adverse drug reaction occurred (0.65%) after the second injection. As a secondary outcome measure, the improvements in the efficacy parameters including total WOMAC score and weight-bearing pain were all significant at both week 13 and 39 compared to the baseline value (P < 0.001), and improvements after the second injection were consistent with those after the initial injection of LBSA0103 (between week 26 and week 39, P < 0.001). Repeated intra-articular injection of LBSA0103 at a 26-week interval is safe without increased risk of adverse drug reactions. Additionally, LBSA0103 is effective in reduction of osteoarthritis knee pain and in maintenance of pain reduction for a 39-week period when a second injection is administered.

Efficacy and safety of single injection of cross-linked sodium hyaluronate vs. three injections of high molecular weight sodium hyaluronate for osteoarthritis of the knee: a double-blind, randomized, multi-center, non-inferiority study.

BACKGROUND: This randomized, double-blind, multi-center, non-inferiority trial was conducted to assess the efficacy and safety of a cross-linked hyaluronate (XLHA, single injection form) compared with a linear high molecular hyaluronate (HMWHA, thrice injection form) in patients with symptomatic knee osteoarthritis. METHODS: Two hundred eighty seven patients with osteoarthritis (Kellgren-Lawrence grade I to III) were randomized to each group. Three weekly injections were given in both groups but two times of saline injections preceded XLHA injection to maintain double-blindness. Primary endpoint was the change of weight-bearing pain (WBP) at 12 weeks after the last injection. Secondary endpoints included Western Ontario and McMaster Universities Osteoarthritis index; patient's and investigator's global assessment; pain at rest, at night, or in motion; OMERACT-OARSI responder rate; proportion of patients achieving at least 20 mm or 40% decrease in WBP; and rate of rescue medicine use and its total consumption. RESULTS: Mean changes of WBP at 12 weeks after the last injection were -33.3 mm with XLHA and -29.2 mm with HMWHA, proving non-inferiority of XLHA to HMWHA as the lower bound of 95% CI (-1.9 mm, 10.1 mm) was well above the predefined margin (-10 mm). There were no significant between-group differences in all secondary endpoints. Injection site pain was the most common adverse event and no remarkable safety issue was identified. CONCLUSIONS: This study demonstrated that a single injection of XLHA was non-inferior to three weekly injections of HMWHA in terms of WBP reduction, and supports XLHA as an effective and safe treatment for knee osteoarthritis. TRIAL REGISTRATION: ClinicalTrials.gov ( NCT01510535 ). This trial was registered on January 6, 2012.

Surgical outcome of intramedullary nailing in patients with complete atypical femoral fracture: A multicenter retrospective study.

BACKGROUND: Management of atypical femoral fracture on bisphosphonate therapy still remains controversy and is reported high rate of complications. The aim of this study was to evaluate the outcome of intramedullary nailing in patients with atypical femoral fracture who took bisphosphonate more than one year through the multicenter retrospective study. METHODS: We gathered 75 atypical femoral fractures from seven institutions between 2009 and 2014. Among them 46 atypical femoral fractures which met the inclusion criteria was evaluated in this study. The average age was 70.1 years (53-80) and the average duration of bisphosphonate use was 5.1 years (1-15 years). Medical records and radiographs were reviewed to determine time to union, union rate, need for revision surgery, restoration of ambulatory function, and complications. RESULTS: Twenty-nine (63%) fractures healed within 6 months without complications. The average time to union except two non-union was 24.9 weeks (11-48 weeks). Two patients (4.3%) underwent revision surgery for non-union and there was no implant failure. Thirty-seven (80.4%) patients achieved their pre-fracture ambulatory function at the final follow up. CONCLUSIONS: Although the incidence of delayed bone healing is high in atypical femoral fracture on bisphosphonate therapy even treated with intramedullary nailing, the incidence of revision surgery and implant failure was relatively lower than those of extramedullary devices.

Open-wedge high tibial osteotomy versus unicompartmental knee arthroplasty: no difference in progression of patellofemoral joint arthritis.

PURPOSE: The purpose of this retrospective comparative study was to evaluate and compare, radiographically and clinically, progression of osteoarthritis (OA) in the patellofemoral (PF) compartment after open-wedge high tibial osteotomy (OWHTO), and unicompartmental knee arthroplasty (UKA) over a minimum follow-up of 5 years. METHODS: In this study, 42 knees in an OWHTO group were compared with 59 knees in a UKA group in terms of radiographic parameters, such as the grading system for OA progression in the PF compartment, and clinical parameters, such as the PF pain and function scores over a minimum follow-up of 5 years. RESULTS: There was no significant difference of OA progression in the PF compartment between the two groups on knee radiography. Compared with the preoperative grades, the UKA group showed significant progression of OA in the medial PF compartment at the final follow-up, whereas the medial PF compartment showed significant stepwise progression by only one grade when compared to the OWHTO group. The PF pain and function scores showed no statistical differences between the two groups at the final follow-up, regardless of OA progression. CONCLUSIONS: There was no significant difference between OWHTO and UKA in terms of progression of OA in the PF compartment or deterioration of PF function score over a minimum follow-up of 5 years. However, the medial PF compartment of the UKA group was minimal, and worsened or progressed by only one grade. LEVEL OF EVIDENCE: III.

Comparison of osteoconductivity and absorbability of beta-tricalcium phosphate and hydroxyapatite in clinical scenario of opening wedge high tibial osteotomy.

The purpose of this study was to compare the osteoconductivity, and absorbability of hydroxyapatite or beta-tricalcium phosphate in clinical scenario of opening wedge high tibial osteotomy Total 41 knees of 40 patients with follow up period of more than 1 year were enrolled. These patients were divided into two groups, Group I (22 knees, 21 patients) used hydroxyapatite and Group II (19 knees, 19 patients) used beta-tricalcium phosphate as a substitute in the opening gap. According to proven method, the osteoconductivity was assessed radiographically by the extent of new bone formation at osteotomy space and absorbability was evaluated by measuring the area occupied by substitute at immediate postoperative, postoperative 6 months and 1 year. Regarding preoperative demographic data, no significant differences were found between two groups. No statistically significant differences were found between two groups regarding lower limb alignment (mechanical femorotibial angle, weight-bearing line%) and posterior tibial slope at postoperative and final follow up radiographs. Concerning the osteoconductivity, there were no significant differences between two groups in any zone. However, the absorption rate was significantly greater in the Group II than in Group I at 6 months (Group I: 13.7 ± 6.8, group II: 35.3 ± 15.8, P = 0.001) and 1 year (Group I: 24.2 ± 6.3, Group II: 49.6 ± 14.3, P < 0.0001). The complications related to bone substitutes were not observed. Both hydroxyapatite and beta-tricalcium phosphate showed satisfactory gap healing without complications and can be successfully used as alternative healing materials in opening wedge high tibial osteotomy. Our study showed that beta-tricalcium phosphate has superior absorbability than hydroxyapatite. But osteoconductivity showed no significant difference.

Computer navigation is effective in reducing blood loss but has no effect on transfusion requirement following primary total knee arthroplasty: a meta-analysis.

PURPOSE: This meta-analysis was designed to evaluate the effects of computer navigation on blood conservation after total knee arthroplasty (TKA) by comparing postoperative blood loss and need for allogenic blood transfusion in patients undergoing computer navigation and conventional primary TKAs. METHODS: Studies were included in this meta-analysis if they compared change in haemoglobin concentration before and after surgery, postoperative blood loss via drainage or calculated total blood loss, and/or allogenic blood transfusion rate following TKA using computer navigation and conventional methods. For all comparisons, odds ratios and 95 % confidence intervals (CI) were calculated for binary outcomes, while mean difference and 95 % CI were calculated for continuous outcomes. RESULTS: Twelve studies were included in this meta-analysis. The change in haemoglobin concentration was 0.39 g/dl lower with computer navigation than with conventional TKA (P = 0.006). Blood loss via drainage was 83.1 ml (P = 0.03) lower and calculated blood loss was 185.4 ml (P = 0.002) lower with computer navigation than with conventional TKA. However, the need for blood transfusion was similar for the two approaches (n.s.). CONCLUSIONS: The primary TKA with computer navigation was effective in reducing haemoglobin loss and blood loss, but had no effect on transfusion requirement, compared with conventional primary TKA. These findings suggest the importance of analysing several blood loss parameters, because each may not always accurately reflect true postsurgical bleeding. LEVEL OF EVIDENCE: Meta-analysis, Level III.

Analysis of Knee Joint Line Obliquity after High Tibial Osteotomy.

The aim of this study was to evaluate which lower extremity alignment (knee and ankle joint) parameters affect knee joint line obliquity (KJLO) in the coronal plane after open wedge high tibial osteotomy (OWHTO). Overall, 69 knees of patients that underwent OWHTO were evaluated using radiographs obtained preoperatively and from 6 weeks to 3 months postoperatively. We measured multiple parameters of knee and ankle joint alignment (hip-knee-ankle angle [HKA], joint line height [JLH], posterior tibial slope [PS], femoral condyle-tibial plateau angle [FCTP], medial proximal tibial angle [MPTA], mechanical lateral distal femoral angle [mLDFA], KJLO, talar tilt angle [TTA], ankle joint obliquity [AJO], and the lateral distal tibial ground surface angle [LDTGA]; preoperative [-pre], postoperative [-post], and the difference between -pre and -post values [-Δ]). We categorized patients into two groups according to the KJLO-post value (the normal group [within ± 4 degrees, 56 knees] and the abnormal group [greater than ± 4 degrees, 13 knees]), and compared their -pre parameters. Multiple logistic regression analysis was used to examine the contribution of the -pre parameters to abnormal KJLO-post. The mean HKA-Δ (-9.4 ± 4.7 degrees) was larger than the mean KJLO-Δ (-2.1 ± 3.2 degrees). The knee joint alignment parameters (the HKA-pre, FCTP-pre) differed significantly between the two groups (p < 0.05). In addition, the HKA-pre (odds ratio [OR] = 1.27, p = 0.006) and FCTP-pre (OR = 2.13, p = 0.006) were significant predictors of abnormal KJLO-post. However, -pre ankle joint parameters (TTA, AJO, and LDTGA) did not differ significantly between the two groups and were not significantly associated with the abnormal KJLO-post. The -pre knee joint alignment and knee joint convergence angle evaluated by HKA-pre and FCTP-pre angle, respectively, were significant predictors of abnormal KJLO after OWHTO. However, -pre ankle joint parameters were not significantly associated with abnormal KJLO after OWHTO.

Total Limb Rotation after Unilateral Total Knee Arthroplasty: Side-to-Side Discrepancy.

Total limb rotation, an important anatomical feature of the lower limb, is defined as any rotation of the lower limb on its longitudinal axis. The aim of the present study was to evaluate the discrepancies of rotational profiles of total limb between nonoperated and operated limb following unilateral total knee arthroplasty. We conducted an analysis of the computed tomography (CT) data from 32 patients undergoing primary unilateral total knee arthroplasty. Using these CT scan, rotational profiles of total limb, such as femoral neck anteversion angle expressed as femoral torsion angle (FTA), tibial torsion angle (TTA), knee joint rotation angle (KJRA), and total limb rotation (TLR) were measured. There were significant discrepancies of FTA and KJRA between operated and nonoperated limb following unilateral total knee arthroplasty. The mean difference of operated and nonoperated side for FTA and KJRA were -6.51 ± 11.88 degrees (p = 0.0041) and -6.83 ± 5.04 degrees (p < 0.001), respectively. However, there were no significant discrepancies of TLR, TTA. These results are due to the compensation effect of KJRA. However, excessive external rotation of the femoral component beyond the compensation effect of prosthetic knee joint can lead to a total limb rotational discrepancy in patient undergoing unilateral total knee arthroplasty.

Outcome of Unicompartmental Knee Arthroplasty: A Systematic Review of Comparative Studies between Fixed and Mobile Bearings Focusing on Complications.

The purpose of this systematic review is to collate results of studies comparing fixed and mobile bearing unicompartmental knee arthroplasty (UKA), focusing on complications and timing for reoperations. Out of 723 results derived from PubMed, EMBASE and Cochrane database search engines on bearings in arthroplasty, 10 studies comparing clinical results of fixed bearings to mobile bearings in UKA were found eligible for analysis. The reoperation rate was calculated using a novel method such as reoperations per hundred component years, and the causes of specific reoperations were investigated. The overall reoperation rate per hundred component years was similar between the mobile bearings (1.392) and fixed bearings (1.377); however, mobile bearings were more susceptible to reoperations in cases with aseptic loosening (0.393>0.255), progression of arthritis (0.428>0.357) and implant dislocation (0.286>0). The overall incidence of complications is similar for fixed and mobile bearing designs in UKA. The discussion on complications presented above may assist surgeons in their choice of bearing design.

Current status of second-look arthroscopy after meniscal allograft transplantation: review of the literature.

INTRODUCTION: Clinical assessments do not accurately reflect the status of meniscal transplants and cannot evaluate the graft condition itself and joint preservation effects of meniscal allograft transplantation correctly. The purpose of this review was to assess the need and to ascertain the indication and the role of second-look arthroscopy for objective evaluation after MAT. MATERIALS AND METHODS: We performed a literature search to identify all published clinical studies on MAT with the following medical subject heading (MeSH) terms: "meniscus," "meniscal transplant," "transplantation and allograft," "meniscal and transplant." Include in the review are studies with at least 6 months clinical, radiological, and/or histological follow-up in human subjects. Evaluation method of MAT was reviewed with an aim to describe the frequency of second-look arthroscopy, its feasibility, patient compliance, purposes, and results. RESULTS: We identified 15 clinical studies that satisfied our inclusion and exclusion criteria. Only two studies always performed second-look arthroscopies. Most of the second-look arthroscopy was conducted mainly for the objective evaluation of meniscal allograft transplantation but, in several studies, arthroscopy was performed to treatment of other knee problem. CONCLUSIONS: Although second-look arthroscopy has inevitably ethical issues, especially for asymptomatic and well-functioning knees, in this review, it could be a more dependable method available to detect meniscal healing if performed for certain indications such as a symptomatic patient with a magnetic resonance image indicating abnormalities.

Open debridement and prosthesis retention is a viable treatment option for acute periprosthetic joint infection after total knee arthroplasty.

PURPOSE: Open debridement with prosthesis retention (ODPR) has been considered as a reasonable treatment option for acute periprosthetic joint infection (PJI) following total knee arthroplasty (TKA). However, multiple recent studies have challenged this contention. This study was undertaken to determine the success rate of ODPR, whether the success rate was affected by the ODPR timing or by the microorganisms. METHOD: We retrospectively reviewed 52 cases of ODPR performed in four institutions to treat acute PJI which met the definition of PJI by the International Consensus Group on PJI. We recorded patient demographics; time from index TKA and symptom duration; the microorganisms involved; and whether the infection was controlled or not. RESULTS: The overall success rate of ODPR was 71 %, and early postoperative infection and acute hematogenous infection had a success rate of 82 and 55 %, respectively. Success rate was associated with a shorter symptom duration in patients with acute hematogenous infections (p = 0.040). However, success was not influenced by the type (p = 0.992) or virulence of the causative microorganisms (p = 0.706). CONCLUSION: ODPR should be considered as a viable treatment option for acute PJI following TKA. The promptness of ODPR is of paramount importance for success of ODPR, rather than the causative organism type or virulence.

Does patella position influence ligament balancing in total knee arthroplasty?

PURPOSE: In vivo comparative gap measurements were performed in three different patella positions (reduced, subluxated and everted) using offset-type-force-controlled-spreader-system. METHODS: Prospectively, 50 knees were operated by total knee arthroplasty using a navigation-assisted gap-balancing technique. The offset-type-force-controlled-spreader-system was used for gap measurements. This commercially available instrument allows controllable tension in patella-reduced position. The mediolateral gaps of knee extension (0°) and flexion (90°) angle were recorded in three different patella positions; reduced, subluxated and everted. Any gap differences of more than 3 mm were considered as a meaningful difference. Correlation between the difference with the demographic data, preoperative radiologic alignment and intraoperative data was analysed. For statistical analysis, ANOVA and Pearson's correlation test were used. RESULTS: The gaps in patella eversion demonstrated smaller gaps both in knee extension and flexion position compared to the gaps of patella reduction position. The amount of decreased gaps was more definite in knee flexion position. Statistically significant difference was observed for the lateral gap of patella eversion compared to gap of patella reduction in knee flexion position (p < 0.05). There were notable cases of variability in knee flexion position. Significant portion of 12 (24 %) knees of patella subluxation and 33 (66 %) knees of patella evertion demonstrated either increased or decreased gaps in knee flexion position compared to the gaps of patella reduction position. CONCLUSION: The gaps in patella eversion demonstrated smaller gaps both in knee extension and flexion position compared to the gaps of patella reduction position. The amount of decreased gaps was more definite in knee flexion position. Therefore, the intraoperative patellar positioning has influence on the measurement of the joint gap. Keeping the patella in reduced position is important during gap balancing. LEVEL OF EVIDENCE: I.

Radiologic bone remodeling pattern around DCPD-coated, metaphyseal-loading cementless short stems in elderly patients.

Concerns exist regarding using short stems during total hip arthroplasties performed in elderly patients. For this study, the authors assessed sequential bone remodeling findings in metaphyseal-loading short stems using serial radiography. A total of 100 consecutive primary THAs using short stems were performed in patients with an average age of 78.3 years. The presence and patterns of radiolucent lines, radiopaque lines, calcar rounding, proximal bone resorption, spot welds, cortical hypertrophy, and intramedullary bone formation around the distal tip were assessed. The final study group comprised 92 hips, and mean follow-up was 60±3 months (range, 48-72 months). At final follow-up, condensations of spot welds were noted in 84 (91.3%) hips. Spot weld formation occurred in all zones except 1 and 4. Calcar rounding was observed in 90 (97.8%) hips. Atrophy of the calcar was noted in 19 (20.6%) hips. Analysis of the proximal zones revealed reactive radiodense lines in zones 1 and 2 (tensile area/shoulder of stem) in 22 (23.9%) hips. A prominent reactive line around the tip of the stem was recorded in 32 (34.8%) hips on radiographs at final follow-up. However, there was no increase in space between the tip of the stem and the radiopaque line. No acetabular or femoral component migrated by more than 1 mm at final follow-up. No acetabular or femoral osteolysis was identified. The radiographic findings of metaphyseal-loading short stems in elderly patients suggest that 91.3% of implants were osseointegrated. No patient required stem revision. Metaphyseal-loading short stems in elderly patients provide continued fixation with adaptive bone remodeling.

Discrepancies of Patellofemoral Indices between Supine and Standing Merchant Views.

PURPOSE: This research was conducted to compare supine and standing Merchant views, to observe radiographic changes of the patellofemoral joint according to weight-bearing conditions, and to evaluate correlation factors affecting patellofemoral joint indices. MATERIALS AND METHODS: Forty-four patients without skeletal problems were selected for this study. Patellar tilt angle, lateral patellofemoral angle, congruence angle, lateral subluxation distance and lateral patellar displacement were measured on each radiograph and evaluated for statistical significance. Possible correlation factors that can affect the radiographic discrepancy were analyzed using the univariate and multivariate regression analysis. RESULTS: In the standing Merchant view, the patellar tilt angle, congruence angle and lateral patellar displacement were significantly decreased (p<0.001), whereas the lateral patellofemoral angle was significantly increased (p<0.001) compared to that in the supine Merchant view. Thigh width (p<0.001, r(2)=0.22) and radiographic Q-angle (p<0.001, r(2)=0.34) were found correlated with the radiographic discrepancy of congruence angle. Discrepancy of the lateral patella displacement increased as radiographic Q-angle increased (p=0.027, r(2)=0.112). CONCLUSIONS: Compared with the supine Merchant view, standing (weight-bearing) Merchant view showed decreased patella tilt angle, congruence angle, and lateral patella displacement. The results indicate that both supine and standing Merchant views should be considered in the radiographic evaluation of the patellofemoral joint.

The weight-bearing scanogram technique provides better coronal limb alignment than the navigation technique in open high tibial osteotomy.

BACKGROUND: Successful outcomes following high tibial osteotomy (HTO) require precise realignment of the mechanical axis of the lower extremity. The present study investigated whether the weight-bearing limb scanogram (WBS) technique provided a more accurate mechanical axis realignment than the navigation technique in open high tibial osteotomy (OHTO). METHODS: This prospective study involved 80 knees (78 patients) undergoing OHTO. The WBS technique was used in 40 knees and the navigation technique in 40 knees. Each technique was performed by a different surgeon in a different hospital. Postoperative coronal limb alignment was assessed using the weight-bearing line (WBL) ratio on full-length standing hip-to-ankle radiographs. RESULTS: We found that the mean postoperative WBL ratio was greater in the WBS compared to the navigation group (p=0.001), and hence the ratio for the WBS group was closer to the ratio target of 62%. There was a greater proportion of WBL ratio outliers in the navigation group than the WBS group (25% vs. 10%, p=0.034). CONCLUSION: We conclude that the WBS technique was more accurate than the navigation technique for restoration of coronal leg alignment in OHTO. LEVEL OF EVIDENCE: Level II.

Quantification of soft tissue balance in total knee arthroplasty using finite element analysis.

Unbalanced contact force on the tibial component has been considered a factor leading to loosening of the implant and increased wear of the bearing surface in total knee arthroplasty. Because it has been reported that good alignment cannot guarantee successful clinical outcomes, the soft tissue balance should be checked together with the alignment. Finite element models of patients' lower extremities were developed to analyse the medial and lateral contact force distribution on the tibial insert. The distributions for four out of five patients were not balanced equally, even though the alignment angles were within a clinically acceptable range. Moreover, the distribution was improved by changing soft tissue release and ligament tightening for the specific case. Integration of the biomechanical modelling, image matching and finite element analysis techniques with the patient-specific properties and various dynamic loading would suggest a clinically relevant pre-operative planning for soft tissue balancing.