The modern Burch-Schneider antiprotrusio cage for the treatment of acetabular defects: is it still an option? A systematic review.

BACKGROUND: A number of papers have been published about the clinical performance of modern rough-blasted titanium Burch-Schneider antiprotrusio cages (BS-APCs) for the treatment of acetabular bone defects. However, no systematic review of the literature has been published to date. METHODS: The US National Library of Medicine (PubMed/MEDLINE), EMBASE, and the Cochrane Database of Systematic Reviews were queried for publications using keywords pertinent to Burch-Schneider antiprotrusio cage, revision THA, and clinical outcomes. RESULTS: 8 articles were found to be suitable for inclusion in the present study in which 374 cases (370 patients) had been treated with modern BS-APCs. Most acetabular bone defects were type 3 according to the Paprosky classification (type 2C: 18.1%, 3A: 51%, and 3B: 28.9%). The overall re-revision rate for the 374 acetabular reconstructions with modern BS-APCs was 11.5% (43 cases). The short-term survival rate of the modern BS-APC construct was 90.6% (339 out of 374 cases), while the mid-term survival rate was 85.6% (320 out of 374 cases), and the long-term survival rate 62% (54 out of 87 cases). The most common reasons for revision were aseptic loosening (5.6%), periprosthetic joint infection (3.8%), dislocation (2.7%), and acetabular periprosthetic fracture (1.9%). CONCLUSIONS: There was moderate quality evidence to show that the use of modern rough blasted titanium BS-APCs in cases of acetabular bone loss has an unacceptably high failure rate (38%). Given that antiprotrusio cages do not provide any biological fixation, we would not recommend the routine use of modern BS-APCs in complex revision THA cases. By contrast, the satisfactory short- to mid-term outcome of modern BS-APCs in combination with their low cost compared to highly porous acetabular implants, make us feel that BS-APCs might still be used in selected elderly or low-demand patients without severe superomedial acetabular bone loss.

[Hip impingement surgery: reimbursement in the German DRG system]. / Impingement-Chirurgie: aufwändige Therapie, unterbewertetes Verfahren?

The financial benefit that orthopaedic surgery provides affects the profitableness for both hospitals and centres for outpatient care. Due to on-going evaluation, surgical techniques have been improved over time. Thus, standardized interventions have resulted in a reduction of remuneration for institutions caring for both outpatients and inpatients, no matter whether private or state insurance was applied. This article depicts current payments for arthroscopic hip intervention. It is also an issue of which surgeons caring for inpatients and outpatients should be aware. The following coding should not be regarded as a recommendation, but simply as a guide.

The clinical outcome of the Metha short hip stem: a systematic scoping review.

INTRODUCTION: Short femoral stems were designed to bridge the gap between conventional straight design stems and hip resurfacing prostheses in total hip arthroplasty (THA). A number of clinical trials have been recently conducted to assess the clinical and safety profile of the cementless, colarless, tapered Metha short hip stem in young or active middle-aged individuals. METHODS: A systematic scoping review was conducted according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. 4 reviewers independently conducted the search using the MEDLINE/PubMed database and the Cochrane Database of Systematic Reviews. These databases were queried with the terms "short" AND "hip" AND "stem". RESULTS: From the initial 773 studies we finally chose 12 studies after applying our inclusion-exclusion criteria. The number of operated hips that were included in these studies was 5048 (mean BMI range: 22.7-35.2, mean age range: 44.4-60.4 years, mean follow-up range: 2-9 years). The mean modified Coleman methodology score was 52.3/100, while it ranged from 31/100 to 63/100. All mean clinical outcome scores that were used in the studies illustrated significant postoperative improvement when compared with the respective initial values. The revision rate of the Metha stem for component-related reasons was 2.5%, while the rate of major complications not requiring revision of the Metha stem was 2.8%. CONCLUSIONS: The Metha stem performs well in young or active middle-aged THA patients. Further studies are required for the assessment of the long-term results.

Clinical and radiographic outcomes with the Nanos™ short-stem hip implant at 24 months: A prospective, single-center study.

AIM: Short-stem total hip arthroplasty is designed to preserve proximal bone stock in case of eventual revision, potentially benefiting younger and more active patients. This prospective, single-center study assessed the safety and performance of the partially neck-sparing Nanos™ short-stem uncemented prosthesis at 24 months using clinical outcome scores and radiographic results. METHODS: Between April 2011 and February 2015, 52 subjects (mean age, 54.9 years) underwent total hip arthroplasty and were followed up at 3, 6, 12 and 24 months. The primary outcome was improvement in quality of life as measured by the Short-Form 36 Mental Component Score (SF-36 MCS). Secondary clinical outcomes included the Harris Hip Score, Hip Disability and Osteoarthritis Outcome Score, Postel Merle d'Aubigné-Score, Activity Level University of California, Los Angeles score, and Pain Visual Analogue Scale. Complications and radiographic images were also recorded at each follow-up. RESULTS: Mean SF-36 MCS score significantly improved from baseline to final follow up at 24 months (61.3 vs. 79.5, respectively; p < 0.001). All secondary clinical outcomes also showed significant improvement (p < 0.001) during this time period. Neutral stem positioning was achieved in 45 subjects (86.5%). Two subjects (3.8%) underwent revisions: one for a periprosthetic fracture unrelated to the study device and another due to a prosthetic joint infection. Intraoperatively, one fissure fracture of the acetabulum occurred. CONCLUSION: Total hip arthroplasty with the Nanos short-stem led to significant clinical improvements and a high subjective satisfaction rate at 24 months. Further follow-up will determine whether these effects are sustained in the long term.

Sustained benefit of autologous matrix-induced chondrogenesis for hip cartilage repair in a recreational athletic population.

PURPOSE: To investigate the clinical outcome of autologous matrix-induced chondrogenesis (AMIC) implementation for mid-sized chondral lesions of the acetabulum in young active patients, and assess their potential to resume an active lifestyle including return to recreational athletic activities. METHODS: Sixty-two patients with full-thickness mid-sized acetabular chondral lesions were studied. All patients who underwent an arthroscopic AMIC procedure for reconstruction of chondral defects were assessed pre-operatively and at least 2 years post-operatively using the Hip disability and Osteoarthritis Outcome Score (HOOS), modified Harris Hip Score (mHHS) and Visual Analog Scale (VAS) for pain. RESULTS: A significant improvement in all three scores at the time of follow-up was found. The mean HOOS improved from 58.8 ± 7.4 pre-operatively to 90.6 ± 7.1 at follow-up (p < 0.001) while the mean mHHS improved from 53.4 ± 6.6 to 82.4 ± 8.2 (p < 0.001). There was a significant decrease from 4.9 ± 1.1 pre-operatively to 1.1 ± 0.8 post-operatively (p < 0.001) in the VAS pain evaluation, indicating that the patients were satisfied with their relief of pain. CONCLUSIONS: The AMIC procedure is an effective single-stage technique for the reconstruction of mid-size chondral defects of acetabulum in amateur athletes. This intervention enhanced the potential for patients to resume recreational athletic activities and the 2-year clinical outcome as evaluated by the HOOS, mHHS and VAS showed significant improvement over the pre-operative evaluations.

Biomechanical Stability and Osteogenesis in a Tibial Bone Defect Treated by Autologous Ovine Cord Blood Cells-A Pilot Study.

The aim of this study was to elucidate the impact of autologous umbilical cord blood cells (USSC) on bone regeneration and biomechanical stability in an ovine tibial bone defect. Ovine USSC were harvested and characterized. After 12 months, full-size 2.0 cm mid-diaphyseal bone defects were created and stabilized by an external fixateur containing a rigidity measuring device. Defects were filled with (i) autologous USSC on hydroxyapatite (HA) scaffold (test group), (ii) HA scaffold without cells (HA group), or (iii) left empty (control group). Biomechanical measures, standardized X-rays, and systemic response controls were performed regularly. After six months, bone regeneration was evaluated histomorphometrically and labeled USSC were tracked. In all groups, the torsion distance decreased over time, and radiographies showed comparable bone regeneration. The area of newly formed bone was 82.5 ± 5.5% in the control compared to 59.2 ± 13.0% in the test and 48.6 ± 2.9% in the HA group. Labeled cells could be detected in lymph nodes, liver and pancreas without any signs of tumor formation. Although biomechanical stability was reached earliest in the test group with autologous USSC on HA scaffold, the density of newly formed bone was superior in the control group without any bovine HA.

Simultaneous bilateral minimally invasive total hip arthroplasty: A comprehensive review of the literature.

Several studies have reported that minimally- invasive total hip arthroplasty (MISTHA) may significantly reduce postoperative pain and results in faster postoperative rehabilitation when compared with the traditional lateral or posterior approach. Regarding bilateral hip osteoarthritis, there is still no consensus whether simultaneous bilateral MIS-THA can be established as the treatment of choice. Therefore, we searched the international databases of Pubmed, Medline, and Cochrane Database of Systematic Reviews using the key words minimally invasive bilateral total hip arthroplasty. From the initial 23 articles we found five clinical studies which met our inclusion criteria. From the perspective of possible intra- and postoperative complications, one-stage bilateral MIS THA was equally safe or safer than two-stage interventions. In addition, from a clinical outcome perspective, the one-stage procedure can be considered to be preferable. Higher blood transfusion requirements, which were expected following the standard bilateral simultaneous THA, seemed to be minimized with the simultaneous bilateral MIS THA. The supine position of the patient minimized the mean operation time. Approaches using the lateral decubitus position of the patient should be avoided in simultaneous bilateral THA due to the increased operation time. There is a lack of randomized, controlled clinical trials, comparing simultaneous bilateral MIS THA with staged bilateral MIS THA. Although simultaneous bilateral MIS THA seems to be efficacious, cost-effective and safe, more clinical trials are required to establish its superiority over the sequential MIS THA.

The clinical outcome of the different HemiCAP and UniCAP knee implants: A systematic and comprehensive review.

The focal metallic cartilage resurfacing is a surgical method that offers an appropriate step between the biological techniques and arthroplasty in middle-aged patients with full-thickness cartilage defects. The advantages of this technique are that it addresses the defect, respects healthy tissues and provides stability and contoured surface similar to a full arthroplasty. A systematic review was conducted according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Two reviewers (MM and DC) independently conducted the search using the MEDLINE/PubMed database and the Cochrane Database of Systematic Reviews (CDSR). These databases were searched for the terms hemicap knee implant and unicap knee implant and knee focal metallic implant. From the initial 21 studies that were evaluated, 10 were eligible for analysis. Considering both the HemiCAP focal implant and the HemiCap® Wave patellofemoral prosthesis, we found a lack of mid- to long-term clinical outcomes in well-designed prospective clinical studies. No Level I or II studies were found, while the limited number of patients who were included undermines the overall clinical results of these studies. The progression of osteoarthritis, the persisting pain and the subsequent high revision or failure rates in the limited available studies with long-term follow-up, seem to be the major drawbacks of these partial resurfacing techniques. Utilization of partial resurfacing for femoral or patellofemoral compartments results in good short-term outcome for middle-aged patients as a step between biological technique and total knee arthroplasty. The surgeon should be cognizant and also notify the patient of the high failure rates that are reported in the literature in mid- to longterm follow-up and ultimately, the decision to perform partial resurfacing should be taken by both the patient and the orthopedic surgeon.

rhBMP-2 in an injectable Gelfoam carrier enhances consolidation of the distracted callus in a sheep model.

BACKGROUND: A major problem associated with distraction osteogenesis is the long time required for consolidation. OBJECTIVE: The goal of this study was to determine whether a percutaneous injection of recombinant human bone morphogenetic protein-2 (rhBMP-2) in a Gelfoam carrier would enhance bone consolidation following distraction. METHODS: A unilateral tibial osteotomy combined with external stabilization was performed in 14 adult sheep. After a latency of four days, distraction was performed at 1.25 millimetres per day for 20 days. On days 23 and 30, the sheep received an injection of rhBMP-2/Gelfoam or buffer/Gelfoam. During the following 50 days, radiographs and in vivo torsional stiffness measurements were obtained weekly. The effect of rhBMP-2 treatment post-mortem was assessed using destructive biomechanical testing, quantitative CT and DXA analysis. RESULTS: The in vivo stiffness measurements of the sheep treated with rhBMP-2 were significantly higher than those of the carrier control group (p< 0.05). These in vivo data were verified by post-mortem biomechanical testing and quantitative CT analysis. The maximum torsional moment observed was 55% greater in the sheep treated with rhBMP-2. CONCLUSIONS: These data support the potential use of rhBMP-2 in an injectable carrier for enhancing consolidation, as it may ultimately lead to shorter treatment times for patients undergoing distraction procedures.

[Livestock-Associated Methicillin-Resistant Staphylococcus aureus: Epidemiological Data from an Orthopaedic Department in North-West Germany]. / Livestock-assoziierter Methicillin-resistenter Staphylococcus aureus ­ Erhebung einer orthopädischen Fachklinik im Hochrisikogebiet Nord-West.

Background MRSA represents a considerable health threat to orthopaedic patients. Throughout the last decade, livestock-associated MRSA emerged increasingly in livestock all over Europe. LA-MRSA broke the species barrier, colonizing and causing infections in humans. Nevertheless, to date there are no studies concerning livestock-associated MRSA and orthopaedic patients. Therefore, we aimed to investigate the prevalence of LA-MRSA in a regional orthopaedic department localized in an area with high-density livestock. Patients and Methods 1544 persons were enrolled in this prospective study. Nasal swabs and questionnaires were collected in patients admitted to the orthopaedic hospital. Nasal carriage was assessed by using selective MRSA agars. MRSA-positive samples were spa typed. Results Overall, the prevalence of MRSA carriage was 3.3%, nearly all spa types were indicative for LA-MRSA. 91% of all LA-MRSA carriers had contact to livestock during the last 6 months before testing. Conclusion Livestock-associated MRSA emerged rapidly over the last few years and will contribute substantially to MRSA infection rates in orthopaedic hospitals. Livestock-associated patients must be screened before admission in order to control infectious complications.

αBSM failed as a carrier of rhBMP-2 to enhance bone consolidation in a sheep model of distraction osteogenesis.

PURPOSE: One of the problems associated with callus distraction is a long time period needed for consolidation of the newly formed bone. The goal of this study was to determine whether percutaneous injections of rhBMP 2 in αBSM would enhance bone consolidation. METHODS: A unilateral tibial osteotomy combined with external stabilization was performed in 20 adult sheep. After a latency of four days, distraction was conducted for 20 days. Sheep were divided into three groups: group 1 received rhBMP-2/αBSM injections at day 23 and 30, group 2 buffer/αBSM injections at day 23 and 30 and group 3 did not receive any injection. The radiographs and in-vivo torsional stiffness measurements were obtained weekly during the following 50 days. Post-mortem bone densitometry (DXA) and mechanical testing were performed. RESULTS: In-vivo stiffness assessments, DXA values and the maximum torsional moment of the sheep tibia treated with two rhBMP-2 injections were not significantly greater than those of both control groups. CONCLUSIONS: Presented application of rhBMP-2 in αBSM failed to enhance bone consolidation in distraction osteogenesis.

A short-stem hip implant with metaphyseal anchorage in patients with developmental dysplasia of the hip.

BACKGROUND: Short-stem implants are routinely used for total hip arthroplasty in younger patients that are more likely to have secondary osteoarthritis than older patients. OBJECTIVE: To investigate the applicability of short-stem hip implants for secondary osteoarthritis due to developmental dysplasia of the hip. METHODS: This study analyzed the clinical and radiological results of patients with developmental dysplasia of the hip (DDH, 58 hips) and compared them to those of patients with primary osteoarthritis (POA, 59 hips) treated with the metaphyseal total hip arthroplasty (Metha®) short stem with metaphyseal fixation. RESULTS: The mean clinical and radiological follow-up periods were 2.9 ± 1.1 years and 3.8 ± 1.9 years, respectively. The mean Harris Hip Score (HHS) significantly increased in both groups over this period (p< 0.0001). The caput-collum-diaphysis (CCD) angle was significantly lower in the POA group prior to surgery and significantly increased in the POA and and decreased in DDH groups, respectively. The preoperative femoral offset was lower in the DDH group and increased significantly after surgery. CONCLUSIONS: The Metha® short stem in patients with DDH allows good reconstruction of joint biomechanics with a good clinical outcome.

Analysis of migration of the Nanos® short-stem hip implant within two years after surgery.

PURPOSE: Short-stem implants provide a bone-preserving alternative in total hip arthroplasty. However, some evidence exists that the smaller implant-bone contact surface may compromise primary stability and impair osseo-integration. The purpose of this study was to analyse the migration characteristics of the Nanos® short stem over two years by means of model-based roentgen stereophotogrammetric analysis (MBRSA). METHODS: Eighteen patients aged 53.6 ± 7.2 years were included. After being treated with a Nanos implant, 14 patients were followed-up radiologically at three, six, 12 and 24 months by means of MBRSA. Early implant migration was calculated. Clinical data have been assessed in addition. RESULTS: Highest translational migration was observed with a mean value of -0.22 ± 0.39 mm along the proximo-distal axis after three months and highest rotational migration with 0.8 ± 3.2° also around the y-axis after two years. The resulting total migration was 0.46 ± 0.31 mm, with the largest proportion occurring within three months after surgery (0.40 ± 0.34 mm). CONCLUSION: The Nanos short-stem hip implant shows only a slight initial migration within three months after implantation, followed by secondary stabilisation. These results suggest both good primary stability and osseo-integration, suggesting a low risk of aseptic loosening.

The Influence of Hip Rotation on Femoral Offset Following Short Stem Total Hip Arthroplasty.

Short stem total hip arthroplasty (THA) is thought to be an advantageous surgical option for young patients. Femoral offset has been identified as an important factor for clinical outcome of THA. However, little is known on functional implications of femoral offset after short stem THA. Importantly, hip rotation influences the projected femoral offset and may lead to significant underestimation. Therefore, a novel method to identify and account for hip rotation was applied to a prospectively enrolled series of 37 patients (48 radiographs) undergoing short stem THA. Repeated measurements were performed and intraobserver and interobserver reliability was assessed and femoral offset was corrected for rotation. Based on this study, rotation-correction of femoral offset is of highest relevance for the correct interpretation in future studies.

Soft-tissue balance in short and straight stem total hip arthroplasty.

The growing numbers of short stem hip implants have redefined total hip arthroplasty with new stem geometries and possible functional differences. Several systematic reviews have reported good clinical results with this new class of stems, although kinematic alterations are still unclear in many aspects. The good clinical results obtained at the authors' institution led to the current study. The authors hypothesized that the geometric alignment of the prosthetic components may be closer to the anatomy of the healthy hip joint, thus leading to better function and clinical satisfaction. An examination via finite element analysis was chosen to model the hip joint and virtually implant a short and a standard straight stem. Findings indicated that anchoring of the short stem allowed favorable positioning in the proximal femur, with the femoral head already in the center of the cup. This positioning was not possible for the straight stem, which required further reduction of the femur by a significant translation into the cup, leading to abnormal soft-tissue balancing. The results from the simulation showed an absolute average deviation of ligamentous fiber strains of 6% for the short stem in 30° of flexion and extension versus 29% and 36% for the standard straight stem in 30° of flexion and extension, respectively. A femoral neck guided orientation of the short stem implant seems to allow a more anatomical reconstruction and thus a more balanced hip in terms of the modeled soft tissues. In contrast, the straight stem alters the head position and induces nonphysiological capsular strains.

Finite element model of a novel short stemmed total hip arthroplasty implant developed from cross sectional CT scans.

BACKGROUND: Numerous short stemmed total hip arthroplasty (THA) implants have been introduced over the last decades. It is questionable if little differences between the implant designs affect stress shielding and bone remodeling. The finite element analysis allows an evaluation of the design rationale of the implant without negative side effects for the patient. OBJECTIVE: We investigated a relatively new short stemmed implant designed from clustered CT datasets of proximal femurs. How does the implant affect femoral bone remodeling? Can we see a positive effect on bone remodeling from the CT based design? METHODS: We used a Finite Element Model that was validated by a prospective dual-energy-x-ray-absorptiometry study to calculate apparent bone density. RESULTS: Apparent bone density (ABD) decreased by 2.3% in the entire femur. Bone mass loss was pronounced in the proximal calcar region. Little ABD increase was seen in the lateral aspect of the cortical ring, in the minor trochanter area and at the lateral aspect of the stem. CONCLUSIONS: ABD reduction occurs in the proximal regions of the femur. The overall bone mass loss was little after THA with the investigated implant. The specific design seems to have no major effect on stress shielding or load distribution.

Feasibility of arthroscopic placement of autologous matrix-induced chondrogenesis grafts in the cadaver hip joint.

An assortment of clinical trials have been done presenting the effectiveness of autologous matrix-induced chondrogenesis (AMIC) for the regeneration of chondral leasions. The purpose of the study was to underline the accessability of the acetabulum and the femoral head through the known portals and prove i) the feasibility of placing the AMIC in the different zones of the hip joint and ii) check for dislocation after joint movement. Six human cadavers underwent hip arthroscopy on both hips. Two chondral lesions were set on each femoral head and two in the acetabulum to evaluate a total of 48 defects. After microfracturing an autologous matrix-induced chondrogenesis graft was placed on these lesions arthroscopically. After repeated joint movement the dislocation of the graft was checked. It was possible to place the AMIC graft in all 48 chondral lesions. The time needed for placing the graft was 8±2.9 minutes. A trend of time reduction could be detected throughout this study as the surgeon gained more experience. For the femoral head, after twenty cycles of joint movement 18/24 spots showed no displacement, 4/24 showed minor displacement (<3 mm) and 2/24 showed major displacement (>3 mm). None showed total displacement. For the acetabulum 22/24 spots showed no displacement and 2/24 showed minor displacement. A combined microfracturing and placing of an AMIC graft of focal chondral lesions of the hip joint can be done arthroscopically. Prospective randomized in vivo studies should compare the results of arthroscopilally placed AMIC grafts with microfracturing and microfracturing alone.

Access to the hip joint from standard arthroscopic portals: a cadaveric study.

PURPOSE: Our purpose was to study and describe the areas of the hip joint that can be safely visualized and operated on using a variety of portals for the central and peripheral compartments. METHODS: Twelve hip joints in 6 human cadavers were examined through 9 different central and peripheral arthroscopic portals. Markings of the accessible areas within the joint were made through an arthroscope. Dissection of the cadavers was carried out for final evaluation of the visible areas and those accessible for instruments. During dissection, anatomic proximity of the portals to relevant neurovascular structures was measured. RESULTS: The central compartment was sufficiently accessible using the anterior, anterolateral, and posterolateral portals, with slight limitations in the posteromedial corner. A more medial portal did not offer substantial advantages regarding accessibility but decreased the safety distance to the femoral nerve. With regard to the peripheral compartment, the combination of the anterolateral and posterolateral portals allowed visualization of most of the joint. It was observed that the structure at highest risk of injury for the central anterior and the peripheral anterolateral portals was the lateral femoral cutaneous nerve. CONCLUSIONS: In hip arthroscopy, the use of the standard anterior, anterolateral, and posterolateral portals allows proper accessibility of the central compartment, with slight limitations in the posteromedial corner. A more medial portal is not recommended with regard to its risk-benefit ratio. The peripheral compartment of the hip joint is sufficiently visible using the anterolateral and posterolateral portals. For treatment of specific pathologic conditions, a variation of these portals improves surgical accessibility. The anatomic structure at highest risk of injury during hip arthroscopy is the lateral femoral cutaneous nerve. CLINICAL RELEVANCE: The general objectives of this study were to prepare surgeons to develop appropriate concepts of surgery and to facilitate preoperative planning.