Immune and stem cell compartments of acetabular and femoral bone marrow in hip osteoarthritis patients

OBJECTIVE

Hip osteoarthritis (OA) affects all components of the osteochondral unit, leading to bone marrow (BM) lesions, and unknown consequences on BM cell functionality. We analyzed the cellular composition in OA-affected acetabula compared to proximal femur shafts obtained of hip OA patients to reveal yet not explored immune and stem cell compartments.

DESIGN

Combining flow cytometry, cellular assays and transcription analyses, we performed extensive ex vivo phenotyping of acetabular BM cells from 18 hip OA patients, comparing them with their counterparts from patient-matched femoral shaft BM samples. Findings were related to differences in skeletal sites and age.

RESULTS

Acetabular BM had a greater frequency of T-lymphocytes, non-hematopoietic cells and colony-forming units fibroblastic potential than femoral BM. The incidence of acetabular CD45⁺CD3⁺ T-lymphocytes increased (95% CI: 0.1770 to 0.0.8416), while clonogenic hematopoietic progenitors declined (95% CI: -0.9023 to -0.2399) with age of patients. On the other side, in femoral BM, we observed higher B-lymphocyte, myeloid and erythroid cell frequencies. Acetabular mesenchymal stromal cells (MSCs) showed a senescent profile associated with the expression of survival and inflammation-related genes. Efficient osteogenic and chondrogenic differentiation was detected in acetabular MSCs, while adipogenesis was more pronounced in their femoral counterparts.

CONCLUSION

Our results suggest that distinctions in BM cellular compartments and MSCs may be due to the influence of the OA-stressed microenvironment, but also acetabular vs femoral shaft-specific peculiarities cannot be excluded. These results bring new knowledge on acetabular BM cell populations and may be addressed as novel pathogenic mechanisms and therapeutic targets in OA.

[Mega-prostheses in revision knee arthroplasty]

BACKGROUND

Due to a predicted increase in primary total knee arthroplasty (TKA), revision TKA will gain importance over the following years. Because the average age of patients receiving a TKA is decreasing the possible need for multiple revisions might increase as well. Despite efforts to minimize bone and soft tissue damage, the resulting bone and soft-tissue loss increases with each revision and will make the use of megaprostheses indispensable in the future.

COMPLICATIONS

The implantation of a mega-prosthesis must be carefully considered and planned, since mega-prostheses in particular are associated with an increased risk of infection and loosening. Mechanical complications, patient-specific problems and periprosthetic infections can be either the cause for or the result of revision surgery of a mega-prosthesis. In the case of a complication, only a salvage procedure, namely an arthrodesis, amputation or-if necessary-the installation of a permanent fistula is commonly recommended.

Customised bi-compartmental knee arthroplasty shows encouraging 3-year results: findings of a prospective, multicenter study

PURPOSE

The purpose of this study was to assess the clinical and patient-reported outcomes of a customised, individually made (CIM) bi-compartmental knee arthroplasty (BKA).

METHODS

A prospectively recruited cohort of 79 patients was implanted with a CIM-BKA (patello-femoral plus either medial or lateral tibio-femoral, iDuo G2 system, Conformis, Billerica MA) at eight centres in the US and Germany. Patients were assessed for the 2011 KSS, KOOS, and ROM pre-operatively and at 2 weeks, 6 weeks, 12 weeks, 1 year, and 2 years post-operatively.

RESULTS

The objective KSS score significantly improved from 69 at the pre-operative visit, to 94 at the 2-year post-operative time-point. Similar improvements were observed for the KSS function and satisfaction domains. Significant improvements from pre-operative levels were observed across all five domains of the KOOS. Two patients have undergone surgery to revise their CIM-BKA implant to total knees, resulting in a survivorship rate of 97.5% at an average follow-up of 2.6 years.

CONCLUSIONS

CIM-BKA compares favourably to published scores as well as revision rates for previously available monolithic OTS-BKA implants. CIM-BKA implants provide surgeons with a viable and patient-specific monolithic implant solution as an option for patients presenting with bi-compartmental disease, who might, otherwise, be treated by performing uni-condylar + patello-femoral joint or bicruciate sparing TKA surgeries. Longer follow-up and higher numbers have to be awaited for further validation of these encouraging early results.

LEVEL OF EVIDENCE

3b (individual case-controlled study).

Periprosthetic infection is the major indication for TKA revision - experiences from a university referral arthroplasty center

Background

We hypothesized, that periprosthetic joint infection (PJI) accounts for the major proportion of first (primary) and repeated (secondary) Total Knee Arthroplasty revisions at our university referral arthroplasty center.

Methods

One thousand one hundred forty-three revisions, performed between 2008 and 2016 were grouped into primary (55%) and secondary (45%) revisions. The rate of revision indications was calculated and indications were categorized by time after index operation. The odds ratios of the indications for primary versus secondary revision were calculated.

Results

In the primary revision group PJI accounted for 22.3%, instability for 20.0%, aseptic loosening for 14.9% and retropatellar arthrosis for 14.2%. PJI (25.6%) was the most common indication up to 1 year after implantation, retropatellar arthrosis (26.8%) 1–3 years and aseptic loosening (25.6%) more than 3 years after implantation.

In the secondary revision group PJI accounted for 39.7%, aseptic loosening for 16.2% and instability for 13.2%. PJI was the most common indication at any time of revision with 43.8% up to one, 35.4% 1–3 years and 39.4% more the 3 years after index operation.

The odds ratios in repeated revision were 2.32 times higher (p = 0.000) for PJI. For instability and retropatellar arthrosis the odds ratios were 0.60 times (p = 0.006) and 0.22 times (p = 0.000) lower.

Conclusions

PJI is the most common indication for secondary TKA revision and within one year after primary TKA. Aseptical failures such as instability, retropatellar arthrosis and aseptical loosening are the predominant reasons for revision more than one year after primary TKA.

[Scaffold-based Bone Tissue Engineering]

Tissue engineering provides the possibility of regenerating damaged or lost osseous structures without the need for permanent implants. Within this context, biodegradable and bioresorbable scaffolds can provide structural and biomechanical stability until the body's own tissue can take over their function. Additive biomanufacturing makes it possible to design the scaffold's architectural characteristics to specifically guide tissue formation and regeneration. Its nano-, micro-, and macro-architectural properties can be tailored to ensure vascularization, oxygenation, nutrient supply, waste exchange, and eventually ossification not only in its periphery but also in its center, which is not in direct contact with osteogenic elements of the surrounding healthy tissue. In this article we provide an overview about our conceptual design and process of the clinical translation of scaffold-based bone tissue engineering applications.

[Osteotomies of the distal tibia]

OBJECTIVE

Restoration of physiological alignment of the distal tibia and thereby restoration of physiological loading of the ankle joint; joint preservation in asymmetric degenerative arthritis of the ankle.

INDICATIONS

Congenital deformities of the distal tibia; acquired deformities of the distal tibia; asymmetric degenerative arthritis with partially preserved cartilage.

CONTRAINDICATIONS

Absolute contraindications comprise severe nicotine abuse, Charcot arthropathy, peripheral polyneuropathy, relevant peripheral arterial vessel disease, poor local soft tissue condition, acute infection and extensive cartilage damage grade 3-4 in the Outerbridge classification in the complete joint.

SURGICAL TECHNIQUE

Medial and lateral open and closed wedge osteotomies and dome osteotomies of the distal tibia are used, and shortening, lengthening and derotating osteotomies of the fibula.

POSTOPERATIVE MANAGEMENT

For 6 weeks, 15-20 kg partial weight-bearing in a below knee cast or a walker orthosis; full weight-bearing depending on osseous healing after 9-12 weeks postoperatively.

RESULTS

Between July 2012 and May 2017, 15 patients (10 men, 5 women) underwent a supramalleor osteotomy. Average age was 41.8 years (range 17-63 years) and the retrospective average follow-up was 28.7 months (range 3-47 months). Mean preoperative AOFAS (American Orthopaedic Foot and Ankle Society) hindfoot score was 54.3 (range 26-86) and postoperatively a mean of 74.2 (44-100). Preoperatively, 9 patients had varus malalignment and 6 patients valgus malalignment; overall, 4 patients developed complications requiring surgical intervention (26.7%). Osteosynthetic material was removed in 60% of the patients.

[Treatment of acetabular bone defects in revision hip arthroplasty using the Revisio-System]

BACKGROUND

Many different systems for the management of primary and secondary acetabular defects are available, each with its inherent advantages and disadvantages. The Revisio-System is a press-fit oval mono-block implant that makes a defect-oriented reconstruction and restoration of the center of rotation possible.

MATERIAL AND METHODS

In this study, we retrospectively reviewed the outcome of 92 consecutive patients treated with this oval press-fit cup due to periacetabular bone loss. The average follow-up was 58.2 months. Defects were classified according to D'Antonio. There were 39 type II, 38 Type III, and 15 type IV defects. After an average of 4.9 years, the implant survival rate was 94.6% with cup revision as the end point and 89.1% with revision for any reason as the end point. The Harris Hip Score increased from 41.1 preoperatively to 62.3 postoperatively. The mean level of pain measured with the Visual Analogue Scale (VSA) was reduced from 6.9 preoperatively to 3.8 postoperatively.

RESULTS

The Revisio-System represents a promising toolbox for defect-orientated reconstruction of acetabular bone loss in revision hip arthroplasty. Our results demonstrate that the implantation of the Revisio-System can result in a good mid-term clinical outcome.

[Refixation of the biceps tendon onto the radial tuberosity using two suture anchors]

OBJECTIVE

Reinsertion of the distal biceps tendon onto the radial tuberosity restoring full force of flexion and supination.

INDICATIONS

Distal biceps tendon avulsion from the radial tuberosity. Acute and chronic tears with a tendon stump, which can be mobilized and reduced to the radial tuberosity in flexion and supination.

CONTRAINDICATIONS

Tears of the musculotendinous junction. Chronic distal biceps tendon tears with wide retraction and the need for tendon graft augmentation. Severe atrophy of the biceps muscle.

SURGICAL TECHNIQUE

In supination, the skin is incised longitudinally for 4 cm, centered over the medial border of the radial tuberosity. Incision starts 2 cm distal from the humeroradial joint line. Bluntly the distal biceps tendon stump is found and mobilized. Preparation and debriding of the radial tuberosity sparing neurovascular structures. Crossing vessel branches are ligated, if needed. Positioning of two spreading anchors into the radial tuberosity and reinsertion of the tendon stump.

POSTOPERATIVE MANAGEMENT

Adjustable elbow movement orthosis adapted to tendon quality and tissue tension for 6 weeks without active flexion or supination. Degree of extension is gradually increased by 20° every 2 weeks. After orthosis treatment is finished after 6 weeks, flexion and supination with weights is not allowed for another 6 weeks.

RESULTS

In a retrospective study of 30 patients with a mean follow-up of 45 months (range 15-80 months), the clinical outcome was good or excellent in 99% of cases. On average, a Mayo Elbow Performance Score of 93 points (range 65-100 points) and a QuickDash of 5 points (range 0-39 points) were achieved.

[Regulation of bone metabolism in osteoporosis : novel drugs for osteoporosis in development]

Bone is continuously regenerated and remodeled as an adaptation to mechanical load. Bone mass and fracture resistance are maintained by a balanced equilibrium between bone formation and bone resorption. Regeneration and response to mechanical load are, however, impaired in osteoporosis and during aging. Bone resorption is enhanced by chronic inflammation while bone formation is altered by rising levels of inhibitors in the aging organism. Core molecular principles of the regulation of bone metabolism in health and disease have been characterized and developed as therapeutic targets. The receptor activator of nuclear factor kappaB ligand (RANKL) and osteoclast-derived protease cathepsin K are important regulators and effectors of osteoclast differentiation and bone resorption. Bone formation is stimulated by bone morphogenetic proteins (BMP) and via the parathyroid hormone receptor and the Wnt signaling pathway. The principles of osteoclast inhibition using bisphosphonates have now been known for almost three decades. Based on more recent knowledge RANKL and cathepsin K have been developed as new therapeutic targets to inhibit bone resorption. While denosumab, a RANKL antibody, has already been introduced into routine treatment strategies, the cathepsin K antagonist odanacatib is currently in the licensing process. Bone formation can also be stimulated by local administration of BMPs, by systemic treatment with the parathyroid hormone fragment teriparatide and by using antibodies targeting the Wnt inhibitor sclerostin. The latter are presently being tested in phase III clinical studies. In the near future a panel of traditional and novel treatment strategies will be available that will enable us to meet the individual clinical needs during aging and for the treatment of osteoporosis.

[Endoprosthetic tumor replacement : Reconstruction of the extensor mechanism and complications]

BACKGROUND

The reconstruction of the extensor mechanism around the knee is an essential part of tumorresection and tumor arthroplasty in orthopaedic oncology for functional rehabilitation of quality of life and daily activities.

OBJECTIVES

Operative procedures, treatment options and management of complications with reconstruction of the extensor mechanism after tumor resection around the knee depend on the type of arthroplasty.

MATERIALS AND METHODS

Description of the different treatment option for extensor deficiency divided into infra- and suprapatellar modalities.

RESULTS

The operative procedure is always an individual decision depending on the size of the tumor and its localisation. The extensor mechanism is reconstructed with autogenic, allogenic or synthetic material in combination with tumor arthroplasty.

CONCLUSIONS

Extensor reconstruction (supra-/infrapatellar) is an essential part of tumor resection and tumor arthroplasty around the knee. Often, low functional results and high levels of complications (arthrofibrosis, rerupture extensor mechanism, periprosthetic joint infection) are seen in these highly demanding cases in orthopaedic oncology.

[Sliding osteotomy of the tibial tuberosity in patellofemoral instability]

OBJECTIVE

The development of a stable patellofemoral joint by distal realignment with normal positioning of the patella.

INDICATIONS

Patellofemoral instability with increased tibial tubercle to trochlear groove (TT-TG) distance ≥ 20 mm and higher Caton-Deschamps patellar height index ≥ 1.3.

CONTRAINDICATIONS

Open epiphyseal and apophyseal plates of the proximal tibia, normal TT-TG distance with normal patellar height, and high-grade chondral lesions of the patellofemoral joint (ICRS grades 3 and 4).

SURGICAL TECHNIQUE

Examination of the knee joint under anesthesia and evaluation of stability and mediolateral translation of the patella. Diagnostic knee arthroscopy and treatment of chondral or osteochondral lesions. Lateral approach to the tibial tuberosity with soft tissue mobilization and exposure of the patellar tendon. Osteotomy is performed in the frontal plane, creating a fragment at least 6 cm long. The tuberosity is slid into the desired position, medially and distally, if necessary, according to preoperative analysis and planning, followed by careful drilling of the posterior tibial cortex and lag screw osteosynthesis.

POSTOPERATIVE MANAGEMENT

Partial weight-bearing of 20 kg in a MECRON knee brace for 6 weeks. Mobilization 0/0/90° from the MECRON knee brace without active knee extension. Isometric training of the thigh muscles with the knee fully extended.

RESULTS

With meticulous planning and implementation, and in cases of severe trochlear dysplasia combined with medial patellofemoral ligament reconstruction, the technique of sliding osteotomy of the tibial tuberosity has a high success rate.

Direct bone morphogenetic protein 2 and Indian hedgehog gene transfer for articular cartilage repair using bone marrow coagulates

OBJECTIVE

Bone morphogenetic protein 2 (BMP-2, encoded by BMP2) and Indian hedgehog protein (IHH, encoded by IHH) are well known regulators of chondrogenesis and chondrogenic hypertrophy. Despite being a potent chondrogenic factor BMP-2 was observed to induce chondrocyte hypertrophy in osteoarthritis (OA), growth plate cartilage and adult mesenchymal stem cells (MSCs). IHH might induce chondrogenic differentiation through different intracellular signalling pathways without inducing subsequent chondrocyte hypertrophy. The primary objective of this study is to test the efficacy of direct BMP2 and IHH gene delivery via bone marrow coagulates to influence histological repair cartilage quality in vivo.

METHOD

Vector-laden autologous bone marrow coagulates with 10(11) adenoviral vector particles encoding BMP2, IHH or the Green fluorescent protein (GFP) were delivered to 3.2 mm osteochondral defects in the trochlea of rabbit knees. After 13 weeks the histological repair cartilage quality was assessed using the ICRS II scoring system and the type II collagen positive area.

RESULTS

IHH treatment resulted in superior histological repair cartilage quality than GFP controls in all of the assessed parameters (with P < 0.05 in five of 14 assessed parameters). Results of BMP2 treatment varied substantially, including severe intralesional bone formation in two of six joints after 13 weeks.

CONCLUSION

IHH gene transfer is effective to improve repair cartilage quality in vivo, whereas BMP2 treatment, carried the risk intralesional bone formation. Therefore IHH protein can be considered as an attractive alternative candidate growth factor for further preclinical research and development towards improved treatments for articular cartilage defects.

Impaction bone grafting for the reconstruction of large bone defects in revision knee arthroplasty

OBJECTIVE

Regeneration of autologous bone stock and formation of a stable implant bed by impaction of morselized bone allograft.

INDICATIONS

Bone loss after septic and aseptic loosening or tumour resection.

CONTRAINDICATIONS

Persistent infection, one-stage septic revision, poor therapeutic compliance, extensive uncontained metaphyseal defects with cortical thinning of the diaphysis.

SURGICAL TECHNIQUE

Whilst the surgeon removes the loose prosthesis, the assistant prepares the graft. The medullary canal is sealed with a cement restrictor. Graft particles of different sizes are densely impacted around a trial stem. The highest level of stability is achieved by using large particles interspersed with small filler particles. Low-viscosity cement facilitates cement penetration and ensures strong interdigitation with the impacted graft mass after implantation of the prosthesis. Uncontained metaphyseal defects are treated with prosthetic augments.

POSTOPERATIVE MANAGEMENT

Gait training, physiotherapy with isometric quadriceps exercises, partial weight-bearing for 6 weeks, resistance training begins 8 weeks postoperatively.

RESULTS

Between 2010 and 2012, 28 patients with large bone defects [Anderson Orthopaedic Research Institute (AORI) grade: 21 × F3, 3 × F2, 13 × T3, 8 × T2] underwent total knee revision with impaction bone grafting. The mean follow-up was 27.7 months (range 21-47 months). On average, patients had undergone 2.5 previous revisions. Implant survival was 82.0 % (95 % CI = 62.5 %-92.1 %) for any reason of revision as the endpoint and 93.1 % (95 % CI = 74.5-98.4 %) for aseptic revision as the endpoint. The mean postoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score was 35.4 (range 3.3-101.6, SD ± 26.2). The mean KSS was 70.6 (range 20-100, SD ± 26.8).

[The distally based adipofascial sural artery flap for the reconstruction of distal lower extremity defects]

OBJECTIVE

Problematic tissue defects in the distal one-third of the lower leg represent a special challenge for the operative therapy. The distally based adipofascial sural artery flap is a safe and effective modification of the classical fasciocutaneous sural artery flap technique and makes the reconstruction in this problematic area more feasible. The surgical aim is soft tissue reconstruction with local tissue avoiding free tissue transfer.

INDICATIONS

Complex or chronic wounds (maximum width of 8 cm) of the distal lower leg with exposed bone, joints, tendons, and/or neurovascular structures, especially in cases of missing skin perforators.

CONTRAINDICATIONS

Arterial vascular disease (stage III-IV), especially peroneal artery occlusion. Postthrombotic syndrome with occlusion of the small saphenous vein. Chronic lymphedema.

SURGICAL TECHNIQUE

Preparation of the vascular pedicle of the distally based flap (including small saphenous vein, sural artery and nerve), the adjacent crural fascia and the subcutaneous fat without a skin island. The pivot point is about 6 cm cranial to the malleolus lateralis. The flap can be raised proximally up to the heads of the gastrocnemius muscle. After harvesting the flap there will be a change in blood flow direction in the small saphenous vein. The donor site can be closed primarily. The flap is covered with meshed split skin graft at the end of surgery.

POSTOPERATIVE MANAGEMENT

Strict elevation of the extremity for 5 days, then flap conditioning.

RESULTS

Between 1997 and 2012, this technique was used in 104 consecutive patients with soft tissue defects in the distal one-third of the lower leg. Flap survival was achieved 91 patients. In 2 patients amputation of the lower leg was necessary at the mid tibia level. In 3 cases flap necrosis occurred, requiring free tissue transfer.

[Open biopsy of bone and soft tissue tumors : guidelines for precise surgical procedures]

OBJECTIVE

The objective of an open biopsy is to obtain a sufficient amount of representative tumor tissue in terms of adequate quality and quantity, without adverse effects on later therapy.

INDICATIONS

Suspected malignancy after non-invasive diagnostic procedures. Histopathologic evaluation of tumor entity and grading. Planning of the definitive tumor resection and initiation of neoadjuvant therapeutic regimen. Obtaining unfixed, fresh-frozen tumor samples for molecular/genetic analyses or tumor tissue bank.

CONTRAINDICATIONS

Hemorrhagic diathesis. Tumor is only accessible with a surgical approach leading to a significant damage of the surrounding tissue. High probability of tumor cell contamination with incisional biopsy. Poor physical status. Poor therapeutic compliance.

SURGICAL TECHNIQUE

The biopsy tract should be carefully planned according to oncological principles. The operation begins with a small incision in longitudinal direction to the extremity. The shortest path between skin and lesion that avoids contamination of other compartments is selected. The biopsy tract should be located within the surgical approach which is later used for definitive tumor resection. During the definitive procedure it should be possible to resect the biopsy approach with adequate surgical margins because it is considered to be contaminated with tumor cells. In principle, a wide resection of the biopsy tract should be possible. During the operation meticulous hemostasis has to be performed because any hematoma around a tumor may contaminate the entire extremity. In cases of an intraosseous tumor a cortical window should be made to obtain intramedullary tumor tissue. Drains should be located in continuity with the skin incision or in direct extension of the wound. Wound closure with intracutaneous suture technique. Excisional biopsy in terms of marginal resection should be performed only in the presence of small, epifascial lesions that are assumed to be benign after completion of basic diagnostic procedures. In cases of larger or subfascial tumors an incisional biopsy should be conducted.

POSTOPERATIVE MANAGEMENT

Compressive dressing to prevent postoperative hematoma. In cases of tumors affecting load-bearing bones, weight-bearing should be prohibited after biopsy, if there is any fracture risk. Upon receipt of the histopathological results the definitive tumor resection is planned.

[Nerve lesions after minimally invasive total hip arthroplasty]

Although there is no clear evidence, minimally invasive hip arthroplasty seems to be associated with slightly higher complication rates compared to standard procedures. Major nerve palsy is one of the least common but most distressing complications. The key for minimizing the incidence of nerve lesions is to analyze preoperative risk factors, accurate knowledge of the anatomy and minimally invasive techniques. Once clinical signs of nerve injury are evident, the first diagnostic steps are localization of the lesion and quantification of the damage pattern. Therefore, clinical assessment of the neurological deficits should be performed as soon as possible. Apart from rare cases of isolated transient conduction blockade or complete transection, the damage pattern is mostly combined. Thus, there can be evidence for dysfunction of nerve conduction (neuropraxia) and structural nerve damage (axonotmesis or neurotmesis) simultaneously. Because the earliest signs of denervation are detectable via electromyography after 1 week, it is not possible to make any reliable prognosis within the first days after nerve injury using electrophysiological methods. This review article should serve as a guideline for prevention, diagnostics and therapy of neural lesions in minimally invasive hip arthroplasty.

[Minimally invasive hip arthroplasty - what must be spared?]

The classical surgical approach to the hip joint has been modified in recent years. The development of minimally invasive surgical techniques promised a particularly gentle soft-tissue preparation with significant benefits in postoperative recovery and intraoperative blood loss for patients undergoing total hip arthroplasty (THA). Exact knowledge of the anatomy of the hip joint and the surrounding structures at risk are essential to avoid complications. Each of the main minimally invasive approaches for THA implicates very specific advantages and disadvantages. Knowing these factors, minimally invasive hip surgery can be performed in a soft tissue-friendly manner. The resulting advantages have to be checked for significant clinical evidence.

[Minimally invasive retrograde drilling of osteochondral lesions of the femur using an arthroscopic drill guide]

OBJECTIVE

Retrograde drilling for penetration of subchondral sclerotic bone in osteochondrosis dissecans (OCD) of the femoral condyle with preserved cartilage integrity. Hereby, revascularization of the OCD and immigration of bone marrow cells to achieve stable reintegration of the OCD into the surrounding subchondral bone.

INDICATIONS

Stable juvenile and adult osteochondrosis dissecans (stage I-II of the International Cartilage Repair Society (ICRS) classification) of the medial and lateral femoral condyle with an intact articular surface and surrounding sclerosis zone, which is visible in the x-ray.

CONTRAINDICATIONS

OCD stage III-IV of the ICRS grading scale. Relative contraindication: preceding retrograde drilling.

SURGICAL TECHNIQUE

Arthroscopic inspection and palpation of the cartilage defect. Minimal incision over the M. vastus medialis (when the defect is located in the medial condyle) or the M. vastus lateralis (when the defect is located in the medial condyle). Preparation and dissection of the fascia of the vastus muscle. Insertion of retractors underneath the vastus muscle to expose the metaphysis of the distal femur. Intraarticular positioning of the arthroscopic drill guide, placement of the wire guide and a Kirschner(K) wire on the femur metaphysis and retrograde drilling with a 2.0-2.2 mm K wire under radiographic visualization. Length measurement of the intraosseous wire distance. Switch the guide mechanism to a multiple hole drill guide and, depending on the defect size, insertion of a further 7-10 K wires of same thickness and defined length.

POSTOPERATIVE MANAGEMENT

Sterile bandage and slightly compressive dressing. Continuous active and passive knee motion. Weight bearing of 20 kg for 6 weeks, with subsequent transition to continuous weight bearing. Radiographic controls at 6 and 12 weeks postoperatively. In case of a persistent sclerosis zone in the control x-ray or clinical abnormalities, control MRI is indicated.

RESULTS

A total of 55 patients with a mean age of 19.6 years were treated using the described technique: 49 patients (89.1%), and 54 knees respectively (35 juvenile OCD, 19 adult OCD), were seen with a mean follow-up of 37.9 months. An improvement was observed in 81.6% of the knees using the radiographic score, i.e., a mean improvement of 1.13 of the radiographic score published by Rodegerdts and Gleissner (preoperative 3.04 vs. postoperative 1.91). Juvenile OCD showed better radiographic results overall (88.2% healing) than adult OCD (66.7% healing).

[Total hip replacement in developmental dysplasia: anatomical features and technical pitfalls]

Total hip arthroplasty is the procedure of choice for most patients with advanced, symptomatic osteoarthritis due to congenital dysplasia of the hip. However, the complexity of arthroplasty is significantly increased because of anatomic abnormalities associated with dysplasia of the hip. In addition the relatively young age of patients may affect survival of the implant. From a biomechanical standpoint the primary surgical objective is reconstruction of the anatomical center of rotation. Independent of the pelvic bone stock the socket should be located as near as possible to the anatomical acetabular location. There are various operative strategies to ascertain sufficient stability of the socket. The anterolateral deficiency of the acetabulum can be reconstructed by bulk femoral autografting or bone impaction grafting. Furthermore controlled perforation of the medial wall or implantation of reinforcement rings and oval sockets have been described. Cementless, biological socket fixation shows superior long-term results compared to cemented cups, especially in these young patients. The location of the reconstructed acetabulum and the desired leg length influence the type of femoral reconstruction and in some cases femoral shortening is required. In this article endoprosthetic reconstructive options for developmental dysplasia of the hip are discussed depending on the femoral and acetabular deformity.

[Replacement of femoral hip prostheses]

Femoral revision of total hip arthroplasty is a technically demanding procedure. Therefore, accurate preoperative planning is essential for good clinical results. With many reconstruction methods available, the decision-making process can be complex. Well established classification systems can facilitate preoperative planning. At the time of revision surgery appropriate implants and instruments have to be available ensuring the possibility of managing operative complications. Primary goals of revision arthroplasty are restoration of the physiological joint biomechanics and primary stable fixation of the revision implant. In consideration of possible repeat revision surgery, cementless stem fixation should be preferred. Modular stems provide significant flexibility in restoring the center of rotation. Depending on the pre-existing femoral defect, osseous grafts can be necessary.The scope and classification systems of femoral osseous defects in revision arthroplasty will be discussed and different treatment options will be outlined, which guide the surgeon in selecting an appropriate method of reconstruction.

Transforming growth factor β1 and laminin-111 cooperate in the induction of interleukin-16 expression in synovial fibroblasts from patients with rheumatoid arthritis

Objectives:

In synovial tissues of patients with rheumatoid arthritis (RA), strong expression of laminins and integrins co-localises with increased expression of inflammatory cytokines. Synovial fibroblasts (SF) contribute to the pathogenesis of RA through increased expression of cytokines and chemoattractant factors, one of which is interleukin-16 (IL16). A study was undertaken to investigate the regulatory pathways of IL16 in SF from patients with RA (RA-SF) and osteoarthritis (OA-SF).

Methods:

SF were seeded in laminin-coated flasks and activated by the addition of cytokines. The expression of IL16 was investigated by quantitative RT-PCR, immunoblotting and ELISA; its biological activity was determined by a cell migration assay. Cell–matrix interactions were investigated by cell binding and attachment assays. Relevant intracellular signalling pathways were studied by immunoblotting and with pharmacological blocking reagents.

Results:

Stimulation of SF with transforming growth factor β1 (TGF-β1) and growth on laminin-111 (LM-111) significantly increased the expression of IL16. Binding to LM-111 induced significantly more IL16 mRNA in RA-SF than in OA-SF (p<0.05). The IL16 cytokine was detected in supernatants of TGF-β1-activated and in LM-111+TGF-β1-activated RA-SF (38 to 62 pg/ml), but not in supernatants of OA-SF. This IL16 regulation involved p38MAPK, ERK1/2 and SMAD2 signalling, but not NFκB.

Conclusions:

Binding of RA-SF to LM-111 in the presence of TGF-β1 triggers a significant IL16 response and thus may contribute to the infiltration of CD4+ lymphocytes into synovial tissues. This mode of IL16 induction represents a novel pathway leading to IL16 production in RA-SF but not in OA-SF, which operates independently of NFκB signalling.

[Haemophilic pseudotumour of the distal femur - a case report and characterisation of this entity]

Haemophilic pseudotumour is a rare disease occurring in 1 % of patients with severe haemophilia as a long-term complication. Because both haemophilia A (factor VIII deficiency) and haemophilia B (factor IX deficiency) are X-linked recessive genetic disorders, pseudotumours are found almost exclusively in men between 20 and 70 years of age. Haemophilic pseudotumour has been defined as a progressive cystic swelling, produced by recurrent haemorrhage, which exerts increasing pressure on nearby structures. As a result, necrosis of skin, muscle and bone can be found. Neurovascular obstruction as well as pathologic fractures are severe complications of this disease. Most patients with pseudotumours are asymptomatic for a long time and many patients report sustaining an injury prior to the development of the tumour. Most haemophilic pseudotumours of the bone are located in the pelvis, femur and hand. We present the case of a 59-year-old male patient suffering from a haemophilic pseudotumour of the right distal femur. After verification of the diagnosis by means of an open biopsy, final surgery with curettage and plombage with bone cement was performed.

Biodegradable magnesium scaffolds: Part 1: appropriate inflammatory response

Current tissue engineering strategies focus on the replacement of pathologically altered tissues by the transplantation of cells in combination with supportive biocompatible scaffolds. Scaffolds for tissue engineering strategies in musculoskeletal research require an appropriate mechanical stability. In recent studies, considerable attention has thus been given to magnesium alloys as biodegradable implants. The aim of this study was to characterize the biocompatibility of magnesium scaffolds by the inflammatory host response. Open porous scaffolds made of the magnesium alloy AZ91D were implanted into the distal femur condyle of rabbits and were compared to autologous bone, which was transplanted into the contralateral condyle in a 3 and 6 months follow-up group. After 3 months, magnesium scaffolds were already largely degraded and most of the original magnesium alloy has disappeared. Concomitantly, a fibrous capsule enclosed the operation site. Histological analysis revealed that the magnesium scaffolds caused no significant harm to their neighboring tissues. This study shows that even fast degrading magnesium scaffolds show a good biocompatibility and react in vivo with an appropriate inflammatory host response. Magnesium alloy based implants are therefore a very promising approach in the development of mechanically suitable and open porous scaffolds for the replacement of subchondral bone in cartilage tissue engineering.

[Heel pain]

Upper and plantar heel pains are differentiated from one another. Plantar heel pain is usually caused by plantar fasciitis. A heel spur is a side effect and is not related to the cause of the symptoms. Upper heel pain is mostly caused by tendonitis of the Achilles tendon or Haglund exostosis. Only through an exact diagnosis is an adequate and usually conservative therapy possible. If the conservative therapy should fail, it is nevertheless important to clarify the indication for surgery to prevent the problems from becoming chronic.

Der Oberflächenersatz am Hüftgelenk

Resurfacing arthroplasty is regarded as an attractive method, especially for the young patient who needs a hip replacement. However, the high expectations regarding this new technique in THR must first be met. Earlier experiences with similar forms of surface replacement have led to high revision rates with early aseptic wear induced component loosening and neck fractures. Technical progresses in production techniques for metal-on-metal articulations with minimized wear have enabled the introduction of new surface replacements for the hip joint. Long-term results of these resurfacing arthroplasties are still due. Femoral neck fractures and femoro-acetabular impingement are possible early complications which require revision. The implantation of these systems requires a high degree of operative skill and experience on the part of the surgeon. Approach dependent trauma to the musculature and endangering of the blood supply to the femoral head is balanced with the positive effect of the preservation of femoral bone stock and better options in case of revision. Whether the younger patient with a higher activity profile and an increased chance of implant loosening actually profits from the resurfacing arthroplasty will be determined in the future.

[Results of vacuum sealing therapy in joint infections]

AIM

At present the vacuum sealing technique is acknowledged as a therapy for acute and chronic wounds. An acceleration of the healing process, due to the vacuum suction with occlusive wound dressing, leads to the shortening of a cost-effective medical treatment. This can be applied to wound treatment and infections of soft tissues, but even today there is only sparse information in this context about joint infections.

METHOD

The results of therapy with the vacuum sealing technique in 68 patients with infections of the joints of an extremity or the trunk were analysed in a retrospective study without a control group. The importance of several patient-related factors for the medical treatment have been analysed.

RESULTS

An adequate treatment of joint infections can be achieved even in the presence of endoprostheses or osteosynthetic material. The following factors have been found to be of significance for a prolonged medical treatment: diabetes mellitus (p=0.0052), obesity (BMI>25) (p=0.0458) and a preceding trauma (p=0.0457).

CONCLUSION

The results confirm the value of the vacuum sealing technique following surgical debridement in combination with resistance tested antibiotic treatment, as a sufficient therapy for joint infections, even in patients with an endoprosthesis. This procedure leads to a safe treatment of the joint infection, combined with a good function of the treated joint, good patient comfort and a short duration of the therapy.

[Radiologic evaluation of cup placement variation in conventional total hip arthroplasty]

PURPOSE

Determination of the amount of variation in conventional acetabular cup positioning (radiological inclination and anteversion) in view of different factors that could influence the measured angles.

MATERIALS AND METHODS

The intended acetabular cup position of 45 degrees inclination and 20 degrees anteversion was checked radiologically in 950 patients who received a cementless total hip replacement. The qualifications of the surgeon, operated side and implant model were recorded and analyzed with respect to a possible correlation with the results. Since a "safe angle" cannot be defined without consideration of other variables, a tolerable deviation of the target position was investigated.

RESULTS

The mean inclination angle was 48.7 degrees (SD 7 degrees, minimum 28 degrees, maximum 75 degrees ). Anteversion was measured with a mean of 18.6 degrees (SD 9 degrees, minimum -9 degrees, maximum 50 degrees ). Assuming an acceptable deviation of +/- 5 degrees from the target position (45 degrees inclination and 20 degrees anteversion), only 22.7 % of the acetabular cups were in this range. In the case of an acceptable deviation of +/- 10 degrees, 34.5 % of the cups were still outside of the acceptable range. The qualifications of the surgeon, the implanted model, as well as the operated side did not have a significant influence on the results.

CONCLUSION

The common implantation technique yielded significant variation with respect to anteversion and inclination. The application of computer-aided navigation in the placement of acetabular cups would help to improve accuracy and reproducibility considerably in total hip arthroplasty.

[Postoperative autologous transfusion from blood drainage after total hip joint arthroplasty--how much value is really there?]

AIM

Are autologous blood transfusions sufficient or do we need the transfusion of unwashed or washed wound drainage blood in total hip arthroplasty?

METHOD

253 patients undergoing total hip arthroplasty were retrospectively randomized to autologous blood transfusion or transfusion of unwashed wound drainage. We compared the haemoglobin and haematocrit levels as well as the rate of complications.

RESULTS

Postoperative blood salvage and reinfusion after total hip joint arthroplasty didn't show any advantages. In 10 % we saw complications after transfusion of unwashed wound drainage.

CONCLUSION

We do not recommend the transfusion of wound drainage.

Expressionsanalyse verschiedener Kollagene und Zytokine in Knorpelzellen aus arthrotisch veränderten Hüft- und Kniegelenken

AIM

Osteoarthritis (OA) is characterized by an irreversible destruction of articular cartilage. This is associated with a multiplicity of factors, causing an increased catabolic metabolism in cartilage. However, the prevalence of the OA is very variable in different joints. Therefore , we conducted a comparative analysis of chondrocytes derived from knee and hip joints with respect to their expression of inflammatory factors, such as IL-1beta, IL-1beta-receptorantagonist, iNOS, components of cartilage matrix (collagen I, II, and VI) as well as vimentin.

METHODS

Different cytokines and proteins were detected by immune-histochemical staining of cartilage samples ex vivo. Further, chondrocytes were isolated from OA knee and hip joints, expanded in vitro and gene expression patterns were investigated by quantitative RT-PCR.

RESULTS

Chondrocytes from knee and hip joints of OA patients express collagenes I, II and VI, IL-1beta and IL-1beta-RA, iNOS as well as Vimentin. A significant difference in gene expression patterns was not found in chondrocytes from the hip joints versus the knee joint ex vivo or in primary culture cells in vitro. However, in vitro the expression of type I collagen exceeded the expression of type II collagen. The IL-1beta-expression was high ex vivo, remained low during primary culture but was significantly elevated after primary culture in hip chondrocytes.

CONCLUSION

Osteoarthritic gene expression patterns in cells derived from hip or knee joints ex vivo and in primary culture were not significantly different. We conclude that the rather frequent occurrence of OA in these joints in comparison to the ankle joint may be associated with a close physiological relation of cells in these joints. However, future studies which will include ankle cartilage must be investigated in further detail.

Multiple skeletal metastases from a giant cell tumour of the distal fibula with fatal outcome

A giant cell tumour is a primary lesion of bone of intermediate severity. Its histogenesis is unclear. In a few cases pulmonary metastases have been described. Multiple skeletal metastases in the absence of sarcomatous change have been observed. We present a case report of a 25-year-old woman with a recurrent giant cell tumour of the distal fibula. After a second recurrence and six years after the initial diagnosis, she rapidly developed multiple bony metastases. The outcome was fatal.

Charakterisierung von humanen Meniskuszellen

AIM

The meniscus of the human knee joint has an important function for the shock absorption, stability and power transmission from the upper to the lower leg. After meniscus injury often a partial or complete resection is necessary. Only injuries in the outer third may heal spontaneously or upon primary suture due to the vascularisation in these segments. After partial or total meniscectomy osteoarthritis of the knee joint is common in a large number of patients. The goal of our investigations was to establish meniscus cell cultures and to characterise the fibrochondrocytes (meniscus cells) in vitro.

METHODS

We examined the expression of different growth factors, cytokines and proteins in human menisci from surgical preparations using immunohistochemistry and RT-PCR analysis.

RESULTS

Human meniscus cells express the collagens I , II, III, and VI, the matrix metalloproteinases-1, -2, -3, -8, and -13, BMP-2, and -4, TGFbeta1, VEGF, IGF-I, and -II, FGF-2, endostatin, iNOS, vimentin, TIMP-1, and -2, aggrecan, IL-1beta, IL-6, and IL-18. Staining with the monoclonal antibody AS.02 in all examined cells confirmed their mesenchymal origin.

CONCLUSION

New strategies for the treatment of meniscus damage can be derived from these results and further advances for the tissue engineering of meniscus tissue can be obtained.

[Pigmented villonodular synovitis]

Pigmented villonodular synovitis (PVNS) is a rare, strongly proliferative disease of the lining of thejoint, synovial bursa and tendon (synovial) sheath. If left untreated, it leads to severe destruction of the joint resulting in an early need for endoprosthetic replacement. The clinical signs are unspecific. Using the diagnostic gold standard MRI, the complete extent of PVNS can usually be determined non-invasively. Once histological confirmation has been obtained, radical tumor resection, synovectomy, possibly curettage, and postoperative irradiation must be applied.