Prosthesis Instability Research Articles

Dual mobility versus conventional total hip arthroplasty in femoral neck fractures (DISTINCT): protocol for a registry-nested, open-label, cluster-randomised crossover trial

IntroductionHip fractures treated with total hip arthroplasty (THA) are at high risk of prosthesis instability, and dislocation is the most common indication for revision surgery. This study aims to determine...

Do Dual-mobility Cups Reduce Revision Risk in Femoral Neck Fractures Compared With Conventional THA Designs? An International Meta-analysis of Arthroplasty Registries.

Dual-mobility cups in THA were designed to reduce prosthesis instability and the subsequent risk of revision surgery in high-risk patients, such as those with hip fractures. However, there are limited data from clinical studies reporting a revision benefit of dual-mobility over conventional THA. Collaboration between anthroplasty registries provides an opportunity to describe international practice variation and compare between-country, all-cause revision rates for dual-mobility and conventional THA. We summarized observational data from multiple arthroplasty registries for patients receiving either a dual-mobility or conventional THA to ask: (1) Is dual-mobility use associated with a difference in risk of all-cause revision surgery compared with conventional THA? (2) Are there specific patient characteristics associated with dual-mobility use in the hip fracture population? (3) Has the use of dual-mobility constructs changed over time in patients receiving a THA for hip fracture? Six member registries of the International Society of Arthroplasty Registries (from Australia, Denmark, Sweden, the Netherlands, the United Kingdom, and the United States) provided custom aggregate data reports stratified by acetabular cup type (dual-mobility or conventional THA) in primary THA for hip fracture between January 1, 2002, and December 31, 2019; surgical approach; and patient demographic data (sex, mean age, American Society of Anesthesiologists class, and BMI). The cumulative percent revision and mortality were calculated for each registry. To determine a global hazard ratio of all-cause revision for dual-mobility compared with conventional THA designs, we used a pseudoindividual patient data approach to pool Kaplan-Meier prosthesis revision data from each registry and perform a meta-analysis. The pseudoindividual patient data approach is a validated technique for meta-analysis of aggregate time-to-event survival data, such as revision surgery, from multiple sources. Data were available for 15,024 dual-mobility THAs and 97,200 conventional THAs performed for hip fractures during the study period. After pooling of complete Kaplan-Meier survival data from all six registries, the cumulative percent revision for conventional THA was 4.3% (95% confidence interval [CI] 4.2% to 4.5%) and 4.7% (95% CI 4.3% to 5.3%) for dual-mobility THA at 5 years. We did not demonstrate a lower risk of all-cause revision for patients receiving dual-mobility over conventional THA designs for hip fracture in the meta-analysis once between-registry differences were adjusted for (HR 0.96 [95% CI 0.86 to 1.06]). A lower proportion of dual-mobility procedures were revised for dislocation than conventional THAs (0.9% versus 1.4%) but a higher proportion were revised for infection (1.2% versus 0.8%). In most registries, a greater proportion of dual-mobility THA patients were older, had more comorbidities, and underwent a posterior approach compared with conventional THA (p < 0.001). The proportion of dual-mobility THA used to treat hip fractures increased in each registry over time and constituted 21% (2438 of 11,874) of all THA procedures in 2019. The proportion of dual-mobility THAs in patients with hip fractures increased over time, but there was large variation in use across countries represented here. Dual-mobility cups were not associated with a reduction in the overall risk of revision surgery in patients with hip fractures. A randomized controlled trial powered to detect the incidence of dislocation and subsequent revision surgery is required to clarify the efficacy of dual-mobility cups to treat hip fractures. Level III, therapeutic study.

Powered Prosthesis Locomotion on Varying Terrains: Model-Dependent Control With Real-Time Force Sensing

Lower-limb prosthesis wearers are more prone to falling than non-amputees. Powered prostheses can reduce this instability of passive prostheses. While shown to be more stable in practice, powered prostheses generally use model-independent control methods that lack formal guarantees of stability and rely on heuristic tuning. Recent work overcame one of the limitations of model-based prosthesis control by developing a class of provably stable prosthesis controllers that only require the human interaction forces with the prosthesis, yet these controllers have not been realized with sensing of these forces in the control loop. Our work realizes the first model-dependent prosthesis knee controller that uses in-the-loop on-board real-time force sensing at the interface between the human and prosthesis and at the ground. The result is an optimization-based control methodology that formally guarantees stability while enabling human-prosthesis walking on a variety of terrain types. Experimental results demonstrate this force-based controller outperforms similar controllers not using force sensors, improving tracking across 4 terrain types.

Improved cell adhesion to activated vapor silanization-biofunctionalized Ti-6Al-4V surfaces with ECM-derived oligopeptides

Titanium implants are widely used in traumatology and various orthopedic fields. Titanium and other metallic-based implants have limited structural and functional integration into the body, which translates into progressive prosthesis instability and the need for new surgical interventions that have enormous social and economic impacts. To enhance the biocompatibility of titanium implants, numerous biofunctionalization strategies have been developed. However, the problem persists, as more than 70% of implant failures are due to aseptic loosening. In this study we addressed the problem of improving the physiological engraftability and acceptability of titanium-based implants by applying a robust and versatile functionalization method based on the covalent immobilization of extracellular matrix (ECM)-derived oligopeptides on Ti-6Al-4V surfaces treated by activated vapor silanization (AVS). The feasibility of this technique was evaluated with two oligopeptides of different structures and compositions. These oligopeptides were immobilized on Ti-6Al-4V substrates by a combination of AVS and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) crosslinking chemistry. The immobilization was shown to be stable and resistant to chemical denaturing upon sodium dodecyl sulfate treatment. On Ti-6Al-4V surfaces both peptides increased the attachment, spreading, rearrangement and directional growth of mesenchymal stem and progenitor cells (MSC) with chondro- and osteo-regenerative capacities. We also found that this biofunctionalization method (AVS-EDC/NHS) increased the attachment capacity of an immortalized cell line of neural origin with poor adhesive properties, highlighting the versatility and robustness of this method in terms of potential oligopeptides that may be used, and cell lineages whose anchorage to the biomaterial may be enhanced. Collectively, this novel functionalization strategy can accelerate the development of advanced peptide-functionalized metallic surfaces, which, in combination with host or exogenously implanted stem cells, have the potential to positively affect the osteoregenerative and osteointegrative abilities of metallic-based prostheses.

Use of Surgical Approach Is Not Associated With Instability After Primary Total Hip Arthroplasty: A Meta-analysis Comparing Direct Anterior and Posterolateral Approaches.

Posterolateral approach (PA) has been historically associated with an increased risk of dislocation after primary total hip arthroplasty (THA), especially when compared with the direct anterior approach (DAA). However, current evidence is inconsistent regarding the risk of dislocation with either approach. The purpose of this study is to determine whether surgical approach influences joint stability. A systematic search in PubMed, MEDLINE, and Embase databases was performed. Randomized controlled trials (RCTs) and non-RCTs comparing DAA with PA in primary THA were included. Pooled effect measure of risk differences, relative risk and mean differences for postoperative dislocation, acetabular implant positioning, and leg length discrepancy were calculated. Twenty-five studies (5 RCTs and 20 non-RCTs) of 7,172 THAs were assessed. There were no significant differences in dislocation rates between approaches (risk difference = -0.00, 95% confidence interval: -0.01 to 0.00; P = 0.92; I2 = 0%). Results were similar in the subgroup analysis of RCTs (P = 0.98), posterior soft-tissue repair (P = 0.50), and learning curve (P = 0.77). The acetabular implant was better positioned within the safe zone in the DAA group (relative risk = 1.17; 95% confidence interval: 1.03 to 1.33; P = 0.01), but no significant differences were found in cup inclination (P = 0.8), anteversion (P = 0.10), and leg length discrepancy (P = 0.54). Dislocation rates after THA are not different between DAA and PA. Furthermore, no differences in the rate of dislocation were associated with cup positioning or surgical factors related with hip instability. Therefore, the surgical approach has little influence in prosthesis instability after primary THA. Level III.

Comparison of bony increased offset-reverse shoulder arthroplasty and standard reverse shoulder arthroplasty outcomes

The purpose of this study is to evaluate functional outcomes and complications between the standard RSA and BIO-RSA. 65 consecutive procedures were performed in 60 patients (40 BIO-RSA and 25 RSA). There was no statistically significant difference in functional outcome, pain and complications.The BIO-RSA can produce comparable, if not better functional results than a standard RSA whilst reducing the rates of scapula notching, prosthesis instability, lost shoulder rotation and poor shoulder contour. It should therefore be considered in all patients presenting with cuff tear arthropathy, massive rotator cuff tear and fracture sequelae.

Mid- and long-term effectiveness of total hip arthroplasty with Ribbed femoral stem prosthesis in 354 cases

To evaluate the mid- and long-term effectiveness of total hip arthroplasty (THA) with Ribbed femoral stem prosthesis. A clinical data of 354 patients (384 hips) with hip disease who underwent THA with Ribbed femoral stem prostheses between October 2006 and May 2016 was retrospectively analyzed. There were 171 males and 183 females, with an average age of 53.4 years (range, 20-82 years). There were 324 cases of single hip and 30 cases of bilateral hips. The cause of THA included the avascular necrosis of the femoral head in 151 cases (159 hips), hip osteoarthritis in 134 cases (136 hips), rheumatoid arthritis in 43 cases (43 hips), ankylosing spondylitis in 20 cases (40 hips), and trauma in 6 cases (6 hips). The Harris score of total 354 patients before operation was 42.34±8.89. Harris scores were used to evaluate hip function after operation. X-ray films were used to determine the length of the lower limb, the radiolucent line on the femur side, the stability of the prosthesis, and the occurrence of stress shielding. The incisions healed by first intention. All patients were followed up 2-11 years with an average of 7.4 years. The Harris score at last follow-up was 80.52±7.61, which significantly increased when compared with preoperative score ( t=134.804, P=0.000). Two cases (2 hips) of prosthetic infections, 3 cases (3 hips) of prothesis loosening, and 4 cases (4 hips) of periprosthetic fractures, and 48 cases (48 hips) of mild to moderate thigh pain occurred after operation. X-ray films showed 76 cases (78 hips) with radiolucent lines on the femur side and stress shielding. According to the Engh's method, there were 364 hips of bone ingrowth, 15 hips of fibrosis ingrowth, and 5 hips of prosthesis instability. The femoral stem subsidence occurred in 25 cases (25 hips), and the difference in leg length discrepancy was more than 10 mm in 5 patients. THA with Ribbed femoral stem prosthesis can achieve satisfactory effectiveness with good initial stability and rapid bone growth. The incidence of stress shielding is relatively high, but the stress shielding has no significant impact on the mid- and long-term survival rate and effectiveness of femoral prosthesis.

Content of blood serum bone tissue metabolism indices in patients with prostheses instability after primary knee joint arthroplasty

Aim. To assess the separate indices of blood serum bone tissue metabolism content in patients with instability of prostheses after the primary knee joint arthroplasty.&#x0D; Materials and methods. The main group joined 40 patients with implant-associated inflammation, the comparison group – 40 patients with primary aseptic instability of prostheses, the control – 20 conditionally healthy donors. The blood serum hPTH and 25-OH Vitamin D content was determined using solid-phase immune-enzyme assay.&#x0D; Results. Among the patients of the main group, blood serum hPTH concentration increased as compared with the control after1 and 12 months following the surgery and compared with each previous observation period; 25-OH Vitamin D level decreased compared with the control before the surgery, after1 and 12 months following the surgical intervention and compared with each previous period of observation. In the patients of the comparison group versus the control values, blood serum hPTH concentration elevated and 25-OH Vitamin D level declined after 1 and 12 months following the surgery and compared with the previous observation period 1 month later.&#x0D; Conclusions. When estimating the blood serum hPTH and 25-OH Vitamin D content in patients with instability of prostheses after the primary knee joint arthroplasty, there were revealed multidirectional changes in their levels, showing bone tissue metabolic disorders.

Reverse shoulder arthroplasty for recent proximal humerus fractures: Outcomes in 422 cases

The ageing of the population is steadily increasing the frequency of displaced proximal humerus fractures (PHFs) in elderly patients. The last decade has seen a shift from hemi-arthroplasty (HA) to reverse shoulder arthroplasty (RSA) in these patients. The primary objective of this study was to assess short- and long-term outcomes of RSA in a large cohort of elderly patients with recent PHFs. The secondary objectives were to evaluate radiological outcomes and short- and long-term morbidity and mortality rates. Outcomes of RSA to treat PHFs in older patients are satisfactory, reliable, and sustained over time. This retrospective multi-centre study included 898 patients with a mean age of 79 years, among whom 422 underwent a standardised clinical and radiological evaluation at least 1 year after RSA. Some patients were re-evaluated twice. An evaluation within the first 5 years was available for 420 patients (≤5-Y group), whereas 119 patients were re-evaluated more than 5 years after RSA (>5-Y group). Some patients had one re-evaluation either within or after 5 years and others had both an early and a late re-evaluation; thus the total number of re-evaluation was greater than the number of patients. Mean active forward elevation was 115°±29°, mean external rotation with the elbow by the side was 17°±19°, mean internal rotation (hand-to-back) was 4.3±2.5 points, mean absolute Constant score was 57±15, and mean Subjective Shoulder Value was 70%±18%. Re-implantation of the tuberosities followed by healing in the anatomical position was associated with significantly better outcomes, notably regarding rotations. Even in the absence of healing in the anatomical position, tuberosity repair was associated with better clinical outcomes compared to tuberosity excision. Humeral loosening occurred in 3.5% of patients and was associated with tuberosity excision. Glenoid loosening was seen in 3.5% of patients and was associated with superior tilt of the glenoid component. The main complication was prosthesis instability, which occurred in 2.5% of patients, a proportion similar to that seen in the general population. Post-operative patient survival was not significantly different from that in the general population of the same age. Prosthesis survival was 91% after 20 years. Clinical outcomes of RSA for PHF in elderly patients were not only satisfactory but also reproducible and sustained over time. Tuberosity re-implantation around the prosthesis is the key step for optimising the functional outcomes, notably by restoring rotations and decreasing the risk of complications (prosthesis instability and humeral loosening). IV, retrospective observational study.

Total Thumb Carpometacarpal Joint Arthroplasty: A Retrospective Functional Study of 28 MOOVIS Prostheses.

Trapeziometacarpal prostheses have been used for more than 50 years in the treatment of first carpometacarpal joint arthritis. Even though this technique is more expensive than trapeziectomy, it has many advantages such as faster convalescence with better patient comfort and improved strength and range of motion. The aim of this study was to report the early functional results of a patient cohort treated with a dual mobility thumb carpometacarpal joint prosthesis. A retrospective study was performed to assess the functional results of 25 patients treated for trapeziometacarpal advanced osteoarthritis (Eaton and Littler stage III) with 28 MOOVIS prostheses. Preoperative and postoperative assessments included pain, range of motion, and pinch and grip strength. The average follow-up time was 27.5 months. The mean pain score measured by a visual analog scale was 8 preoperatively and 1 postoperatively. The mean preoperative Kapandji opposition score was 7 and counter-opposition score was 1; postoperative scores were 10 and 4, respectively. The grip strength improved after the surgery and the results were compared separately between dominant and nondominant sides. Final functional results were good: the mean Quick Disabilities of the Arm, Shoulder and Hand Questionnaire score was 12, and the mean Michigan Hand Outcomes score was 87%. Total joint arthroplasty with a dual mobility prosthesis appears to be a satisfactory solution in our series. The absence of prosthesis instability encourages us to recommend this technique for the treatment of advanced trapeziometacarpal osteoarthritis for people having an activity without too many manual constraints.

Radial head replacement with metal prosthesis and reduction with stabilization of the distal radio-ulnar joint as a treatment of established Essex-Lopresti injury

Objective To investigate the effect of radial head replacement with metal prosthesis and reduction with stabilization of the distal radio-ulnar joint as a treatment of established Essex-Lopresti injury. Methods From March 2012 to December 2015, 5 patients with established Essex-Lopresti injury, whose radiuses had moved proximally since radial head had been resected in the earlier operation, were operated in our department, including 4 males and 1 female, aged from 25 to 50 years (average, 38.8 years). The interval from the radial head resection to the operation in our department was 2 to 7 months (average, 4.6 months). All the 5 patients were operated with radial head replacement with metal prosthesis under no longitudinal stress, and 4 of them got distal ulnar shortening for reduction of the distal radio-ulnar joint. 2 of the 5 cases acquired distal radial-ulnar joint stability after reduction, and the other 3 could not acquired stability and needed open reduction and repairing ligament structure of the wrist and pinning fixation for 4-6 weeks. The Mayo elbow and wrist function score were used to evaluate pre- and post-operative function, with recording the range of motion of the elbow, forearm and wrist. Results All the 5 patients were followed-up for 24 to 60 months (average 45 months). The Mayo elbow function score was improved from preoperative 62 (range, 45-75) to 96 (range, 80-100) at the latest follow-up. The Mayo wrist functional score was improved from 54 (range, 15-65) to 81 (range, 55-90) at the latest follow-up. All patients got significant improvement of involved upper extremity function, without proximal shifting of radius, radial head prosthesis failure or instability of the distal radio-ulnar joint. Conclusion It is effective for treatment of established Essex-Lopresti injury to replace radial head with metal prosthesis and to reduce and stabilize the distal radio-ulnar joint with distal ulnar shortening while necessary. Key words: Radius fractures; Dislocations; Arthroplasty, replacement; Osteotomy

A multimodal approach prevents instability after total hip arthroplasty: A 1 year follow-up prospective study

IntroductionJoint dislocation is one of the most frequent complications after hip arthroplasty. Multiple strategies have demonstrated ability to prevent instability when used in isolation, but the effect when more than one intervention is implemented has not been measured. The purpose of this study is to assess the rate of dislocation after implementation of a protocol of combined strategies for prevention of instability. Materials and methodsConsecutive patients undergoing primary total hip replacement for hip osteoarthritis between February 2012 and June 2014 were included. A multimodal protocol including patient education, use of large femoral heads, posterior soft-tissue repair, and intraoperative adjustment of limb length and hip offset was applied. Dislocation episodes were documented trough medical records review and a telephonic follow-up at 3 and 12 months after surgery. ResultsDuring the period of study 331 patients were included, mean age was 66 years and 68.8% were females. Only 0.91% of patients were lost to follow-up. Eighty-nine percent of patients received all interventions. Cumulative dislocation rate at 3 months was 0.60% and 0.90% at 12 months. ConclusionsThe implementation of a multimodal protocol for prevention of prosthesis instability produces a low rate of dislocation, which compares favorably with benchmarks. We recommend the use of a combination of multiple interventions to prevent this complication.

Surgical treatment after a failed trapeziectomy: A case report

Several treatment options exist to surgically treat end-stage trapeziometacarpal osteoarthritis. Trapeziectomy is recognized as leading to a mostly acceptable functional outcome. Although rarely encountered, persisting failure of the trapeziectomy is difficult to address. We present a case where several procedures were subsequently performed to treat a failed trapeziectomy condition. First, a trapeziometacarpal prosthesis (Arpe®, Biomet®) was inserted with the two components reversed: the cup in the first metacarpal and the stem in the scaphoid. This prevented normal mobility and resulted in a non-functional, chronically painful joint. Revision arthroplasty was performed with a dual-mobility component (Ebony®, Stryker®), replacing the trapezium to articulate with the first metacarpal and the scaphoid. This restored the first column's length but led to prosthesis instability only 4months after implantation. Finally, first column arthrodesis with iliac bone graft interposed between the first metacarpal and scaphoid achieved an acceptable outcome.

Total hip arthroplasty using cementless avantage cup in patients with risk of hip prosthesis instability.

The aim of the study was to assess total hip arthroplasty procedures using the cementless Avantage cup in women with additional risk factors for postoperative hip instability. A total of 280 cementless Avantage and Avantage Reload cups were implanted in 260 women aged between 29 and 79 years (60.9 years on average) in the years 2004-2010. In 217 women, there was at least one additional risk factor for prosthesis dislocation. The survival of the cup was assessed by using the necessity of cup replacement as an endpoint of the study. The statistical analyses used the Fisher test to assess the difference in the necessity of revision surgery between the Avantage and Avantage Reload cups, and the Kaplan Meier method was used to evaluate the effective functioning time of the prosthesis. Additionally, tests were conducted on the surface layer of 2 not used and 4 removed cups. 239 patients (259 arthroplasties) were subjected to the final examination. The follow-up period ranged from 2.7 to 9.7 years, 7.0 years on average. None of the patients demonstrated postoperative prosthesis instability. Aseptic loosening was observed in 19 cups in 18 women (7.3%). Intra-prosthetic dislocation occurred 4 times, and in two cases it was combined with loosening of the cup. Revision surgery was required more often in patients with the Avantage cup (9.5%, 17 out of 179) in comparison to the Avantage Reload (2.5%, 2 out of 80). However, the observed differences did not reach the level of statistical significance. The cumulative survival rate of the Avantage cup was 0.94 at 5 years and 0.86 at 8 years. 1. Avantage cups reduce the risk of postoperative hip instability. 2. Patients with cementless Avantage cups should be closely monitored for signs of aseptic loosening.

Dental implant fractures - aetiology, treatment and case report.

This study aimed to investigate the etiology, clinical manifestations, and treatment options of dental implants fractures through a literature review and to relate a clinical report. A literature review was performed using the Medline database and this paper describes a case demonstrating the management of implant fracture. Twenty two articles were selected in the present literature review. Nowadays the use of dental implants to rehabilitate completely and partially edentulous patients became the best treatment option; however, this treatment is suitable to failure. The fracture of implant body is a possible complication. The fracture of implant body is a late complication and is related to the failure in implant design or material, non-passive fitting of the prosthetic crown and overloading. Clinically, prosthesis instability and spontaneous bleeding are observed. Three options of treatment have been indicated: complete removal of implant fragment, maintenance of implant fragment, and surface preparation of the fragment with insertion of a new abutment. The literature indicates the complete removal of the fragment as the best treatment option.

Aseptic glenoid loosening or failure in total shoulder arthroplasty: revision with glenoid reimplantation

Reimplantation of a new glenoid component for symptomatic glenoid failure after total shoulder arthroplasty (TSA) is a well-established surgical strategy. In case of aseptic glenoid loosening or failure, revision of TSA by reimplantation of a cemented glenoid implant would be a reliable therapeutic option. This retrospective multicenter study included 42 TSAs with symptomatic failed glenoids revised by reimplantation of an all-polyethylene (PE), cemented glenoid component. All patients were reviewed clinically and radiologically, with a mean follow-up of 74 months. The failed initial glenoid component was metal backed in 32 cases and PE cemented in 10. The main cause of glenoid failure was component loosening in 19 cases (46%) and PE wear or dissociation in 23 (54%). Associated complications were very frequent, including rotator cuff tears, subscapularis insufficiency, and prosthesis instability. At last follow-up, 7 patients (17%) had already been re-revised because of symptomatic recurrent glenoid loosening. The overall rate of recurrent glenoid loosening (re-revision plus radiologic loosening) was 67%. Soft-tissue problems and prosthetic instability were significantly associated with recurrent loosening. Of the 10 associated bone grafts performed during the revision procedure, all were partially or totally lysed. At follow-up, the mean Constant score was 57 points (gain of 16 points) and the mean active anterior elevation was 125° (gain of 19°). This study suggests that revision of a TSA with reimplantation of an all-PE cemented glenoid component does not solve the problem of glenoid loosening. Soft-tissue failure and prosthetic instability are underestimated preoperatively and may explain, in part, the high rate of recurrent glenoid loosening.

Instability following Total Knee Arthroplasty

Background Knee prosthesis instability (KPI) is a frequent cause of failure of total knee arthroplasty. Moreover, the degree of constraint required to achieve immediate and long-term stability in total knee arthroplasty (TKA) is frequently debated. Questions This review aims to define the problem, analyze risk factors, and review strategies for prevention and treatment of KPI. Methods A PubMed (MEDLINE) search of the years 2000 to 2010 was performed using two key words: TKA and instability. One hundred and sixty-five initial articles were identified. The most important (17) articles as judged by the author were selected for this review. The main criteria for selection were that the articles addressed and provided solutions to the diagnosis and treatment of KPI. Results Patient-related risk factors predisposing to post-operative instability include deformity requiring a large surgical correction and aggressive ligament release, general or regional neuromuscular pathology, and hip or foot deformities. KPI can be prevented in most cases with appropriate selection of implants and good surgical technique. When ligament instability is anticipated post-operatively, the need for implants with a greater degree of constraint should be anticipated. In patients without significant varus or valgus malalignment and without significant flexion contracture, the posterior cruciate ligament (PCL) can be retained. However, the PCL should be sacrificed when deformity exists particularly in patients with rheumatoid arthritis, previous patellectomy, previous high tibial osteotomy or distal femoral osteotomy, and posttraumatic osteoarthritis with disruption of the PCL. In most cases, KPI requires revision surgery. Successful outcomes can only be obtained if the cause of KPI is identified and addressed. Conclusions Instability following TKA is a common cause of the need for revision. Typically, knees with deformity, rheumatoid arthritis, previous patellectomy or high tibial osteotomy, and posttraumatic arthritis carry higher risks of post-operative instability and are indications for more constrained TKA designs. Instability following TKA usually requires revision surgery which must address the cause of the instability for success.

Transapical Valve Implantation After David Operation and Stenting of the Descending Aorta

This case report illustrates our experience with transapical minimally invasive aortic valve implantation in a patient with an extended aneurysm of the thoracoabdominal aorta, who had previously undergone a replacement of the ascending aorta with concomitant aortic valve reconstruction (David procedure). Endovascular stent grafting of the descending aorta was also performed. The implantation of a 23-mm SAPIEN valve (Edwards Lifesciences, Irvine, CA) did not interfere with the existing 26-mm aortic Hemashield prosthesis (Boston Scientific, Natick, MA) or the previously implanted endograft in the descending aortic position. No paravalvular leakage with aortic valve regurgitation, prosthesis instability, or coronary malperfusion was seen after valve implementation.

Der Ω-Connector: ein Modul zur gelenkigen Ankopplung von Titantotalprothesen im Mittelohr

Hearing improvement after reconstruction of a defect ossicular chain depends on material, design and - crucially - coupling of the prosthesis. Coupling a total ossicular replacement prosthesis to the stapes footplate can be problematic and lead to prosthesis instability. In order to solve this problem, the Omega Connector was developed, a module allowing the middle ear surgeon to couple a titanium total prosthesis to the stapes footplate in a flexible, angle-variable manner. The Omega Connector is made of pure titanium and consists of three compenents: head, neck and base plate. The head allows a jointed coupling to the stem of a titanium total prosthesis. Positioned between the remnants of the stapes crura, the bas plate proves for a stable connection with the stapes footplate. The Omega Connector was implanted during 14 revisions surgeries. In 10 of these surgeries a total ossicular replacement prosthesis was removed which was implanted at an earlier date and which was fixed and no longer functioning. In all 14 cases it was possible intraoperatively to position the Omega Connector correctly and to couple it to a titanium total prosthesis. The postoperative hearing gain was between 10 to 25 dB, with an average of 18 dB. For the first time, the Omega Connector offers to the surgeon the option to couple a titanium total prosthesis via a micro ball joint. Hearing results achieved so far are satisfying. The results confirm the advantages of the Omega Connector during implantation of a titanium total prosthesis. For a final evaluation, long-term studies have yet to be made.

Journal of Hand Surgery

Long-term outcomes of closed reduction and percutaneous pinning for the treatment of distal radius fractures. Glickel SZ, Catalano LW, Raia FJ, Barron OA, Grabow R, Chia B. J Hand Surg Am. 2008;33:1700–1705.