[Minimally invasive anterior approach]. / Der minimal-invasive anteriore Zugang.

The minimally invasive direct anterior approach for total hip arthroplasty (THA) was first published in 1985. Since then the technique has been further improved and the indications have been extended. The approach utilizes the muscle gap between the tensor fasciae latae muscle on the lateral side and the sartorius muscle on the medial side. This muscle gap allows a direct and quick approach to the hip joint with good muscle preservation. During preparation of the femur the tensor fasciae latae muscle is at risk of being damaged. The lateral cutaneous nerve of the thigh (NCFL) and its branches are also in danger of being damaged during skin incision and dissection of the subcutaneous tissue. In this article the technique, risks and current clinical results of THA using the minimally invasive direct anterior approach are described. The results from the literature, as well as own results are compared to the traditional transgluteal lateral Bauer approach and discussed. Reviewing the literature, special attention has been given to the incidence of NCFL lesions, damage of the tensor fasciae latae muscle and positioning of the cup. Especially for the latter, the general view is hindered in the minimally invasive technique.

Fabrication of polycaprolactone collagen hydrogel constructs seeded with mesenchymal stem cells for bone regeneration.

The osteogenic differentiation of bone marrow-derived human mesenchymal stem cells (MSCs) in a collagen I hydrogel was investigated. Collagen hydrogels with 7.5 x 10(5) MSCs ml(-1) were fabricated and cultured for 6 weeks in a defined, osteogenic differentiation medium. Histochemistry revealed morphologically distinct, chondrocyte-like cells, surrounded by a sulfated proteoglycan-rich extracellular matrix in the group treated with bone morphogenetic protein 2 (BMP-2), while cells cultured with dexamethasone, ascorbate-2-phosphate, and beta-glycerophosphate displayed a spindle-shaped morphology and deposited a mineralized matrix. Real-time polymerase chain reaction (RT-PCR) analyses revealed a specific chondrogenic differentiation with the expression of cartilage-specific markers in the BMP-2-treated group and a distinct expression pattern of the osteogenic markers alkaline phosphatase (ALP), type I collagen, osteocalcin (OC), and cbfa-1 in the group treated with an osteogenic standard medium. The collagen gels were used to engineer a cell laden medical grade epsilon-polycaprolactone (PCL)-hydrogel construct for segmental bone repair showing good bonding at the scaffold hydrogel interface and even cell distribution. The results show that MSCs cultured in a collagen I hydrogel are able to undergo a distinct osteogenic differentiation pathway when stimulated with specific differentiation factors and suggest that collagen I hydrogels are a suitable means to facilitate cell seeding of scaffolds for bone tissue engineering applications.

[Implementation of standardized postoperative pain therapy for orthopaedic patients. Comparison between unsystematic and standardized pain therapy]. / Implementierung einer standardisierten Schmerztherapie bei postoperativen orthopädischen Patienten. Vergleich einer unsystematischen mit einer standardisierten Schmerztherapie.

BACKGROUND: The painless clinic and postoperative pain therapy are currently major issues in the management of surgical procedures. The aim of this study was to evaluate the benefit of a standardized pain therapy on the postoperative pain level after orthopaedic procedures. PATIENTS AND METHODS: We investigated two different groups of patients who underwent an orthopaedic surgical procedure. Group 1 (n = 249) received a pain therapy which was based on an individual and surgery-dependent concept whereas group 2 (n = 243) was treated with a standardized pain therapy concept. The effect of the treatment was monitored with a VAS-based protocol. RESULTS: Up to day 9 after surgery there was a significant difference between the two groups in regard to the postoperative pain. The patients of group 2 had less pain but had more unwanted side effects caused by the pain therapy during the first 3 days after surgery. Mobility and mental disposition were positively affected. CONCLUSION: The implementation of a standardized pain therapy is successful in reducing postoperative pain. Mobility and mental disposition are also influenced positively. As a consequence the incidence of unwanted side effects is rising.

Multiphasic collagen fibre-PLA composites seeded with human mesenchymal stem cells for osteochondral defect repair: an in vitro study.

A promising approach for the repair of osteochondral defects is the use of a scaffold with a well-defined cartilage-bone interface. In this study, we used a multiphasic composite scaffold with an upper collagen I fibre layer for articular cartilage repair, separated by a hydrophobic interface from a lower polylactic acid (PLA) part for bone repair. Focusing initially on the engineering of cartilage, the upper layer was seeded with human mesenchymal stem cells (hMSCs) suspended in a collagen I hydrogel for homogeneous cell distribution. The constructs were cultured in a defined chondrogenic differentiation medium supplemented with 10 ng/ml transforming growth factor-beta1 (TGFbeta1) or in DMEM with 10% fetal bovine serum as a control. After 3 weeks a slight contraction of the collagen I fibre layer was seen in the TGFbeta1-treated group. Furthermore, a homogeneous cell distribution and chondrogenic differentiation was achieved in the upper third of the collagen I fibre layer. In the TGFbeta1-treated group cells showed a chondrocyte-like appearance and were surrounded by a proteoglycan and collagen type II-rich extracellular matrix. Also, a high deposition of glycosaminoglycans could be measured in this group and RT-PCR analyses confirmed the induction of chondrogenesis, with the expression of cartilage-specific marker genes, such as aggrecan and collagen types II and X. This multiphasic composite scaffold with the cartilage layer on top might be a promising construct for the repair of osteochondral defects.

[Cell based therapy for the treatment of femoral head necrosis]. / Zellbasierte Therapie der Femurkopfnekrose.

The goal of the therapy for necrosis of the femoral head in adults is the preservation of the femoral head and, therefore, avoidance of total joint replacement. Core decompression is known to reduce the intraosseous pressure and additionally provides the opportunity to introduce bioactive materials, substances and cells into the core tract. These include vascularized and non-vascularized bone grafts, allogenic and synthetic bone substitutes, osteogenic and angiogenic growth factors, as well as different progenitor cells. In particular, the use of cell-based strategies has great therapeutic potential and could play an important role in the treatment of femoral head necrosis in adults in the future. In this article, we summarize the existing clinical experience of current cell-based strategies for the treatment of femoral head necrosis in adults, and present a therapeutic approach using bone marrow stem cells (TRCs: tissue repair cells). in combination with a beta-TCP matrix.

Expression of the angiomatrix and angiogenic proteins CYR61, CTGF, and VEGF in osteonecrosis of the femoral head.

Angiogenesis and bone repair are closely linked processes. VEGF, CYR61, and CTGF have been identified as signaling factors that control angiogenesis and could be important in fracture healing. The purpose of this study was to investigate the expression of these signaling factors in osteonecrosis of the femoral head. Twenty-one bone cylinders were retrieved from hips of patients with osteonecrosis of the femoral head at different ARCO stages. Immunohistochemistry for CD34, CYR61, CTGF, and VEGF expression was done on each bone cylinder representing the different regions of osteonecrosis (necrosis, fibrosis, transition zone, and edematous area). VEGF, CYR61, and CTGF were expressed in samples with osteonecrosis. Particularly VEGF and CYR61 were highly expressed in the edematous area. CYR61 was also highly expressed in the transition zone. CTGF was expressed mainly in the area of marrow fibrosis and edema. CYR61, CTGF, and VEGF are expressed to different degrees in the different repair zones of osteonecrosis. Particularly, the high expression of VEGF and CYR61 in the edematous area may represent a consequence of hypoxia and indicate a role of these proteins in the repair processes ongoing in osteonecrosis.

Anterior cruciate ligament constructs fabricated from human mesenchymal stem cells in a collagen type I hydrogel.

BACKGROUND: Disruptions of the anterior cruciate ligament (ACL) of the knee joint are common and are currently treated using ligament or tendon grafts. In this study, we tested the hypothesis that it is possible to fabricate an ACL construct in vitro using mesenchymal stem cells (MSC) in combination with an optimized collagen type I hydrogel, which is in clinical use for autologous chondrocyte transplantation (ACT). METHODS: ACL constructs were molded using a collagen type I hydrogel containing 5 x 10(5) MSC/mL and non-demineralized bone cylinders at each end of the constructs. The constructs were kept in a horizontal position for 10 days to allow the cells and the gel to remodel and attach to the bone cylinders. Thereafter, cyclic stretching with 1 Hz was performed for 14 days (continuously for 8 h/day) in a specially designed bioreactor. RESULTS: Histochemical analysis for H and E, Masson-Goldner and Azan and immunohistochemical analysis for collagen types I and III, fibronectin and elastin showed elongated fibroblast-like cells embedded in a wavy orientated collagenous tissue, together with a ligament-like extracellular matrix in the cyclic stretched constructs. No orientation of collagen fibers and cells, and no formation of a ligament-like matrix, could be seen in the non-stretched control group cultured in a horizontal position without tension. RT-PCR analysis revealed an increased gene expression of collagen types I and III, fibronectin and elastin in the stretched constructs compared with the non-stretched controls. DISCUSSION: In conclusion, ACL-like constructs from a collagen type I hydrogel, optimized for the reconstruction of ligaments, and MSC have been fabricated. As shown by other investigators, who analyzed the influence of cyclic stretching on the differentiation of MSC, our results indicate a ligament-specific increased protein and gene expression and the formation of a ligament-like extracellular matrix. The fabricated constructs are still too weak for animal experiments or clinical application and current investigations are focusing on the development of a construct with an internal augmentation using biodegradable fibers.

Knee arthroplasty for spontaneous osteonecrosis of the knee: unicompartimental vs bicompartimental knee arthroplasty.

Spontaneous osteonecrosis of the knee (SON) is an osteonecrosis that mainly affects the medial femoral condyle. In endstage SON, knee arthroplasty is the therapy of choice. Because of the unicompartimental nature of the knee, unicondylar knee arthroplasty is considered an ideal implant for treatment of this condition. The purpose of this study was to prove that the long-term results of unicondylar implants are better than the results of bicondylar implants for the treatment of SON. All patients treated for SON between 1984 and 2000 have been recorded. Two groups were formed according to the implant used. In all patients the preoperative radiograph was analyzed according to stage and size of the osteonecrotic lesion and the osteoarthritic changes. Postoperatively, the Knee Society Score and the radiograph were recorded. Thirty-nine patients were included in this study, of which 23 patients were treated by a unicondylar implant and 16 by a bicondylar implant. On a short-term basis, unicondylar implants had better clinical results; however, on a long-term basis bicondylar implants were better. In comparison, only unicondylar implants had to be revised. Radiolucency lines were mainly observed in patients with unicondylar impants and large areas of osteonecrosis. Our long-term results suggest that patients with SON are better treated by bicondylar implants. The reasons for the higher failure rate for unicondylar implants are poor bone stock and secondary arthritic changes.

[Osteochondral lesions of the talus -- indications for MRI with a contrast agent]. / Osteochondrale Läsionen am Talus - Indikationen zur MRT mit Kontrastmittel.

AIM: This study aims to establish the indication for a pre- and postoperative MRI examination with an intravenous contrast agent in patients with an osteochondral lesion of the talus. METHODS: 20 patients with an osteochondral lesion of the talus in the different stages according to DiPaola were prospectively examined preoperatively and 6 months postoperatively by an MRI investigation with an i. v. contrast agent. The Weber ankle score was determined pre- and postoperatively. A correlation was calculated between MRI and arthroscopic findings of an osteochondral lesion (Spearman-rho). RESULTS: There was a significant correlation among the radiological, the MRI and the arthroscopically determined locations. With regard to staging only 12 out of 20 lesions were staged correctly by MRI using arthroscopy as a gold standard. Due to metal artifacts and morphological changes the postoperative MRI could not be used for staging. CONCLUSION: A preoperative MRI investigation is indicated in patients with ankle pain of unknown origin, a normal radiograph and a suspected osteochondral lesion of the talus. MRI is not indicated to determine the localization and the stage of an osteochondral lesion. A postoperative MRI is only necessary for the exclusion of a secondary pathology.

Transient bone marrow edema syndrome progressing to avascular necrosis of the hip - a case report and review of the literature.

Transient bone marrow edema syndrome (TMES) is a rare disease of unknown etiology. Diagnosis is made by exclusion. There is still controversy as to whether TMES is considered to be a reversible form of avascular necrosis (AVN), a disease entity of its own or a form of non-traumatic algodystrophy. We here describe the extremely rare occurrence of three cases of TMES that progressed to AVN.

Treatment of transient bone marrow oedema of the hip--a comparative study.

Between 1990 and 2000, we treated 43 patients with transient bone marrow oedema of the hip. Five were treated with nonsteroidal antiinflammatory drugs (NSAIDs) and limited weight bearing, and 38 by core decompression followed by limited weight bearing. At follow-up 2-10 years later, all patients were assessed by a structured interview as well as the Harris hip score (HHS) and the Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC). Both groups reached the same clinical outcome (HHS and WOMAC). Core decompression enabled a significantly faster recovery. There were no complications, but progression to avascular necrosis was seen in both groups. Core decompression induced fast pain relief, making it the preferable treatment.

Transient marrow edema syndrome of the hip: results after core decompression. A prospective MRI-controlled study in 22 patients.

BACKGROUND: Transient marrow edema syndrome (TMES) of the hip is a disease of acute onset and severe functional disability. There is histological evidence for an ischemic etiology of TMES of the hip. Core decompression as applied for avascular necrosis (AVN) of the hip is therefore a therapeutic alternative to conservative therapy, the latter leading only to a reduction of symptoms but never a shortening of the course of the disease. METHODS: Between January 1998 and June 2000, 22 hips with TMES were treated with core decompression in our department. TMES was diagnosed by exclusion. MRI was done preoperatively and at 6 months postoperatively. The postoperative MRI result was classified into three categories. RESULTS: After an average of 7.2 (range 1-30) days, all patients were pain-free after core decompression. In 2 patients, TMES progressed to AVN despite core decompression. All others had no signal alterations of the head of the femur on MRI after 6 months. The postoperative Harris Hip Score (HHS) in patients with TMES was on average 93.7 (range 77-95); in patients with AVN, the postoperative HHS was 47 (range 45-49). CONCLUSION: Our results demonstrate that core decompression of the hip significantly shortens the natural course of disease of TMES of the hip.

Arthroscopic treatment of septic joints: prognostic factors.

From 1987 to 1993, 88 patients (average age 48 years, range 3 months to 83 years) with septic arthritis were treated at the orthopaedic clinic König Ludwig Haus of the University of Würzburg by arthroscopic means consisting of joint debridement and application of suction drains, combined with appropriate antibiotics and early functional treatment. The series consisted of 78 knees, 8 shoulders and 3 ankles. At the first visit to our clinic, patients typically presented with fever, leucocytosis, elevated sedimentation rate and localized findings in almost every joint involved (generalized tenderness, swelling, effusion, painful and limited range of motion). All the patients were taken to the operating room on an emergency basis. Broad-spectrum antibiotics were given before the initial culture was evaluated, and its sensitivity was determined. Recovery from arthritis by elimination of joint effusion and disappearance of the inflammatory syndrome occurred in all the joints except for 3 (1 knee joint and 2 shoulders). The number of arthroscopic procedures needed to become free from infection depended on the one hand on the time between onset of symptoms and arthroscopic surgery and on the other on the kind of microorganism discovered. At the average follow-up evaluation after 2.5 years (range 6 months to 5 years), the functional results were excellent or good in 61% of the patients, satisfactory in 20% and poor in 19% from our series. This functional outcome depends on the degenerative changes of the joint before infection, patient's age, and the time interval between onset of symptoms and surgical intervention; indirectly, the time lapse between the onset of infection and surgical intervention also had an influence on the intraoperative macroscopic appearance.

Treatment of congenital spondyloptosis in an 18-month-old patient with a 10-year follow-up.

STUDY DESIGN: Case report. OBJECTIVES: To present the case of a patient with congenital spondyloptosis treated and followed over 10 years. SUMMARY OF BACKGROUND DATA: The surgical management of spondyloptosis in children is variably reported in the literature. Some authors propose that posterior fusion in situ is a safe and reliable procedure, whereas others suggest that reduction of the slipped vertebra may prevent some of the adverse sequelae of in situ fusion, which include nonunion, bending of the fusion mass, and persistent lumbosacral deformity. Many investigators advocate a combined anterior and posterior fusion using instrumentation. METHODS: At the time of the first symptoms an 18-month-old boy with congenital spondyloptosis of L5-S1 was referred to the authors' institution. Because of the progression of pain, neurologic disturbance, mild foot deformity, muscle contractures, and lumbosacral kyphosis, surgical intervention was undertaken. Operative intervention began with a resection of the L5 lamina and wide bilateral L5 nerve root decompression. This was followed by anterior subtotal resection of L5 and interbody bone graft of the morcelized vertebral body for fusion from L5 to S1. The next step was reduction of the spondyloptosis and stabilization by posterior instrumentation L2-S1 with a sacral Cotrel-agraffe device. RESULTS: The procedure achieved almost complete reduction of the spondyloptosis with near-normal restoration of lumbar lordosis allowing more physiologic lumbar spinal biomechanics. There were no neurologic complications. After surgery there was no suggestion of back pain or gait disturbance and no progression of any deformity. CONCLUSION: In the treatment of severe congenital spondylolisthesis a staged procedure of decompression, reduction, and instrumented fusion is recommended for those cases in which intervention is indicated.

Transient bone marrow oedema of the foot.

We treated ten patients who on the basis of MRI were suspected to have transient bone marrow oedema. In eight cases the talus was affected, in one the cuboid and in one the navicular bone. All patients had acute onset pain at the ankle. Four were treated with core decompression and had an immediate pain relief. Six were treated conservatively and became also pain-free but with considerable delay.

[5- to 8-year results of total hip endoprosthesis implantation with the Müller straight shaft prosthesis (cemented TiAlNb shaft)]. / 5-bis 8-Jahres-Ergebnisse nach Hüfttotalendoprothese mit der Müller-Geradschaftprothese (zementierter TiAlNb-Schaft).

The aim of this study was to obtain mid-term results after total hip arthroplasty (THA) with cemented titanium stems. In all, 184 patients with a total of 202 THAs (cemented titanium stem) were clinically and radiologically examined after an average follow-up of 6 years (5-8). The recruitment was 86%. The Harris score was determined clinically. Radiologically, the directly postoperative radiographs were compared to the control radiographs according to the recommendations of Gruen et al. and Johnston et al. In 2 cases (1%) septical complications appeared after 2 years, which were treated in two-stage surgery. To date, revisions after loosening have been carried out in 3 cases (1.5%). This is equivalent to a revision rate of 2.5%. Three further cases showed evidence of loosening in more than 5 radiolucent lines (RLL), according to Gruen, making close-meshed controls necessary. Clinically, in all of the 6 cases of aseptic loosening, the Harris score remained above 80 points. In 36 cases, more than one RLL, compared to the postoperative radiographs, was ascertained and mainly found in zones 1, 7, 8, and 14. Substantial subsidence or varus could only be observed in one case. The clinical results in the Harris score were good or excellent in 78% and satisfactory in 20%. With an average of 75 at the time of follow-up, the age of the patients was, according to the indication that only patients above age 60 are to receive cemented-stem prostheses, clearly advanced. The body weight was significantly higher (82 kg; d = 2.4) in those 6 patients having evident RLL, than in patients without RLL. The ratio body weight to surface of the stem was especially different (1.5 kg/cm2 versus 1 kg/cm2; P < 0.005) in the two groups. This did not apply to sex or activity of the patient, size or kind of stem, Harris score, ectopic ossification, or body weight index. The biggest possible stem should be implanted. Not all cemented titanium stem prostheses are necessarily affected with a high rate of loosening at a mid-term follow-up.

[Standardized testing of bone implant surfaces with an osteoblast cell culture cyste. III. PVD hard coatings and Ti6Al4V]. / Standardisierte Testung von Skelett-Implantatoberflächen mit einem Osteoblasten-Zellkultursystem. III. PVD-Hartstoffbeschichtungen und Ti6Al4V.

The effect of titanium-based PVD coatings and a titanium alloy on the proliferation and differentiation of osteoblasts was investigated using a standardised cell culture system. Human fetal osteoblasts (hFOB 1.19) were cultured on titanium-niobium-nitride ([Ti,Nb]N), titanium-niobium-oxy-nitride coatings ([Ti,Nb]ON) and titanium-aluminium-vanadium alloy (Ti6Al4V) for 17 days. Cell culture polystyrene (PS) was used as reference. For the assessment of proliferation, the numbers and viability of the cells were determined, while alkaline phosphatase activity, collagen I and osteocalcin synthesis served as differentiation parameters. On the basis of the cell culture experiments, a cytotoxic effect of the materials can be excluded. In comparison with the other test surfaces, [Ti,Nb]N showed greater cell proliferation. The [Ti,Nb]N coating was associated with the highest level of osteocalcin production, while all other differentiation parameters were identical on all three surfaces. The test system described reveals the influence of PVD coatings on the osteoblast differentiation cycle. The higher oxygen content of the [Ti,Nb]ON surface does not appear to have any positive impact on cell proliferation. The excellent biocompatibility of the PVD coatings is confirmed by in vivo findings. The possible use of these materials in the fields of osteosynthesis and articular surfaces is still under discussion.

Cytokine response of human macrophage-like cells after contact with polyethylene and pure titanium particles.

The aim of this study was to establish a human macrophage cell culture system to examine the effect of polyethylene (PE) and titanium particles on cytokine release by macrophage-like cells (MLC) and to quantify this response with respect to the nature and concentration of particles. Human monocytic leukemia cells were differentiated under standard conditions with vitamin D3 and granulocyte macrophage-colony-stimulating factor. Cells were characterized by fluorescence-activated cell-sorter Scan of CD 14 expression analysis as well as a phagocytosis test exploiting fluorescence-labeled particles of bacteria] walls. To achieve a relevant contact between the floating PE particles (approximately 1 microm in size) and MLC, a rotation device was used (15 rotations/min) during incubation. The same was done with the titanium particles. Cell culture supernatants were then analyzed for interleukin (IL)-1beta, IL-8, and tumor necrosis factor (TNF)-alpha using the enzyme-linked immunosorbent assay technique in the absence or presence of particles. Rotation of incubated MLC alone did not influence the secretion of TNF-alpha, but it enhanced secretion of IL-1beta and IL-8 about 30-fold compared to background levels. Both PE and titanium particles significantly enhanced MLC cytokine release, the amount of which depended on the concentration of particles. Using 40 X 10(8) PE particles (0.7 x 10(8) titanium particles) and 10(6) MLC, the maximal release of IL-1beta was about 20-fold (7-fold titanium particles) higher than that of the rotating control sample. The stimulation of IL-8 release was 4-fold (3-fold titanium particles) and of TNF-alpha. 300-fold (170-fold titanium particles) compared to controls. MLC were viable (>90% cell survival) at concentrations less than 108 x 10(8) polyethylene particles per 10(6) MLC and 16 x 10(8) titanium particles per 10(6) MLC. Rotation per se as well as exposure to increasing concentrations of PE and titanium particles stimulates cytokine release (TNF-alpha, IL-1beta, IL-8) by macrophages in vitro. This in vitro model resembles the in vivo situation near arthroplasties, where implant particles make contact with inflammatory cells, such as macrophages. Cytokine release by macrophages may impair osteoblast function as well as stimulate bone resorption by osteoclasts and macrophages, thereby causing aseptic loosening of arthroplasties. Our in vitro model provides a reproducible human cell system that might shed light on the pathogenesis of particle disease and might serve as a reproducible in vitro test system for the biocompatibility of foreign materials.

Hybrid total knee arthroplasty.

A prospective study of a hybrid total knee arthroplasty (TKA) with an uncemented femoral component and cemented tibial and patellar components was performed to combine the advantage of a press-fit femur while avoiding the problems in uncemented tibial and patellar implants. A total of 329 posterior cruciate-preserving TKA were studied at an average of 4.7 years after surgery: 84% of the knees had at most mild or occasional pain, 68% had good or excellent knee scores, and 62% could walk more than 1000 m. The function scores were 40% good or excellent in this collective, with an average age of 69.4 years at surgery. The component position and alignment were biomechanically correct. Radiolucent lines were observed regularly at the edges of the tibial and femoral components. There were no revisions for aseptic loosening. Hybrid TKA provides good results comparable to cemented TKA.