Schatzker II tibial plateau fractures: Anatomically precontoured locking compression plates seem to improve radiological and clinical outcomes.

INTRODUCTION: The design of anatomically precontoured locking compression plates (LCP) allows the placement of angular stable screws right underneath the reduced joint surface fragments. To date, there is a lack of evidence supporting the broad utilization of these implants in split depression fractures to the lateral tibial plateau. Thus, aim of the present matched pair retrospective cohort study was to investigate the radiological and clinical outcomes of anatomically precontoured LCP compared to conventional plate and screw osteosynthesis in Schatzker II fractures. MATERIAL AND METHODS: The institutional databank was searched for Schatzker II fractures from 2010 to 2016. Patients that underwent open reduction and internal fixation with anatomically precontoured 3.5 mm LCP or conventional 4.5 mm l-shaped plates and screws were included. CT scans and radiographs were analyzed. Details of the operative procedures and secondary events were collected. A matched pair analyses was conducted in a best fit manner. The primary outcome parameter was the Rasmussen Radiological Score approximately one year postoperatively. Secondary outcome parameters were the medial proximal tibial angle (MPTA), the Rasmussen Clinical Score and the WOMAC Score after a follow up of at least three years. RESULTS: A total of 50 patients was included. Patient age, gender distribution, size and depression depth of the lateral joint surface fragments, frequency of utilizing bone grafts or substitutes and lateral meniscus repair as well as subsequent implant removal were comparable across the groups. Immediately postoperatively, the Rasmussen Radiological Score revealed no differences. After a mean of 64.2 weeks, the radiological outcome was significantly better in the LCP 3.5 group (RRS 8.2 vs. 6.3 points, p<0.001; MPTA 89.5 vs. 92.0°, p = 0.001). After a mean clinical follow-up of 4.5 years, the Rasmussen Clinical Score (22.9 vs. 27.8 points, p<0.001) and the WOMAC score (24.3 vs. 16.0 points, p = 0.04) revealed significantly impaired results in the conventional group. CONCLUSION: Anatomically precontoured LCP prevent the subsidence of the reduced joint surface fragments more sufficiently and allow for improved patient outcomes compared to conventional plates and screws. The utilization of anatomically precontoured LCP should therefore closely be considered for internal fixation of any split depression fractures to the lateral tibial plateau.

Immunohistochemical analysis of sensory corpuscles in human transplants of the anterior cruciate ligament.

BACKGROUND: Sensory nerve endings in ligaments play an important role for the proprioceptive function. Clinical trials show that the sense of body position does not fully recover in the knee joint after reconstructive surgery of the ruptured anterior cruciate ligament. The aim of this study is to identify sensory corpuscles in autogenous and allogenous transplants of the ligament and to compare their quantity between the used allografts and autografts. METHODS: Thirty-three patients were included in this study. Three patellar tendon allografts, 14 patellar tendon autografts and 12 semitendinosus autografts were harvested during revision surgery after traumatic rerupture of the graft. The control consisted of 4 healthy anterior cruciate ligaments after fresh rupture. After haematoxylin staining, immunohistochemical analysis was performed using antibodies against S100, p75 and PGP9.5. Microscopical examination was carried out, and the number of mechanoreceptors was counted. Statistical analysis was performed using the Mann-Whitney U test. RESULTS: Two types of mechanoreceptors were identified in each graft: Ruffini corpuscles and free nerve endings. The number of Ruffini corpuscles per square centimeter was the highest in the control. Comparing the grafts, the highest number of receptors could be detected in the semitendinosus autograft. The amount of free nerve endings was higher in the semitendinosus and patellar tendon autografts than in the control; the allografts showed the lowest number of receptors. With increasing time after reconstruction, the number of both types of receptors showed a decrease in the semitendinosus graft, whereas it increased in the patellar tendon graft and allograft. The number of mechanoreceptors in the semitendinosus and patellar tendon graft decreased over time after graft-failure, whereas it increased slightly in the allograft. CONCLUSION: This study was the first to identify mechanoreceptors in human transplants of the anterior cruciate ligament. The partial increase in the number of receptors over time after reconstruction could indicate a reinnervation of the grafts.

Cancellous allogenic and autologous bone grafting ensure comparable tunnel filling results in two-staged revision ACL surgery.

OBJECTIVES: Patients with recurrent instability after anterior cruciate ligament (ACL) reconstruction often present with enlarged or misplaced tunnels and bone grafting is required prior to the actual revision reconstruction. Autologous bone grafting features limited quantity and donor site morbidity. These problems may be eliminated utilizing cancellous bone allografts, but their efficiency and reliability have not been investigated systematically. The aim of the present study was to compare tunnel filling rates attained by utilizing either allogenic or autologous cancellous bone grafts. MATERIALS AND METHODS: A total of 103 consecutive patients were enrolled retrospectively. All patients suffered from recurrent instability and underwent either allogenic or autologous cancellous bone grafting. Computed tomography (CT) was carried out before and after the bone grafting procedure. Based on preoperative CT scans, positioning and maximum diameter of the femoral and tibial tunnels were determined. Tunnel filling rates were calculated as a ratio of pre- and postoperative tunnel volumes. Primary outcome was the tibial tunnel filling rate. Femoral filling rates and density of the grafted bone were assessed secondarily. RESULTS: Preoperative CT scans revealed no significant differences between the two groups regarding distribution of misplacement and widening of the femoral or tibial tunnel. Postoperative CT scans were conducted after an interval of 5.2 months. Tunnel filling rates of 74.5% (± 14.3) femoral and 85.3% (± 10.3) tibial were achieved in the allogenic compared to 74.3% (± 15.9) femoral and 84.9% (± 9.4) tibial in the autologous group. With p values of 0.85 at the femur and 0.83 at the tibia, there were no significant differences between the groups. The density of the grafted bone revealed significantly higher values in the allogenic group. CONCLUSIONS: Utilizing cancellous bone allografts in two-staged revision ACL surgery provides for sufficient and reproducible filling of enlarged or misplaced tunnels. The filling rates are comparable to those achieved with autologous bone grafting. Advantages of allografts are the unrestricted quantity and the absence of any harvesting procedure.

Pain relieve without impairing muscle function after local infiltration anaesthesia in primary knee arthroplasty: a prospective randomized study.

PURPOSE: Purpose of the current study was to compare early effectiveness of pain relieve of 3 in 1 regional pain catheter to local infiltration anesthesia (LIA) in primary total knee arthroplasty (TKA). Secondary endpoint was quadriceps muscle strength after both procedures. MATERIAL AND METHODS: A single-center, prospective, randomized controlled trial was performed. Patients eligible to TKA were either randomized into group 3 in 1 regional pain catheter (C), or group local infiltration anesthesia (L). Pain relieve was assessed by visual analogue scale (VAS) at rest and under physical activity (PA) prior to surgery (t0) and at days one through six. In addition, quadriceps muscle strength ( = straight leg raise) was tested according to the Manual Muscle Testing Scale. Functional outcome was measured using the Oxford Knee Score (OKS) preoperatively and 6 months postoperatively. RESULTS: 121 patients were included in the study. 59 (48.8%) patients were allocated to group C, 62 (51.2%) patients to Group L. No differences concerning pain level evaluated by VAS could be detected between the groups at any time. Comparing straight leg raise test group L was significantly superior over the complete postoperative period (p < 0.03). The mean OKS decreased significantly (p < 0.001) from preoperatively 34.2 ± 7.5 points to 16.9 ± 6.0 points at the six months final follow-up. Regarding OKS there were no intergroup differences at the final follow-up at 6 months postoperative. CONCLUSION: There is no significant difference in pain relieve comparing LIA to 3 in 1 catheter in perioperative pain management in TKA. The advantage of LIA is unimpaired quadriceps muscle function in the short-term follow-up.

Outcomes of revision anterior cruciate ligament reconstruction secondary to reamer-irrigator-aspirator harvested bone grafting.

INTRODUCTION: Patients with widened or misplaced tunnels may require bone grafting prior to revision anterior cruciate ligament (ACL) reconstruction. Utilising reamer-irrigator-aspirator (RIA) harvested bone from the femur showed promising filling rates. Nevertheless, the procedure has neither been validated in a larger population nor been assessed with regards to radiological and clinical outcome of the subsequently conducted revision ACL reconstruction. Therefore, the aim of this study was to evaluate tunnel filling rates, positioning of the revision tunnels and outcome parameters of such two-staged revision ACL reconstructions. MATERIAL AND METHODS: A total of 15 consecutive patients were prospectively enrolled in this case series. CT scans were analysed before and after autologous RIA harvested bone grafting. Tunnel volumes and filling rates were calculated based on manual segmentation of axial CT scans. Revision ACL reconstruction was carried out after a mean interval of 6.2 months (±3.7) and positioning of the revision tunnels was assessed by plane radiographs. The mean follow-up was 19.8 months (±8.4) for objective evaluation and 37.1 months (±15.4) for patient reported outcomes. The clinical outcome was assessed by the quantification of the anterior tibial translation, the IKDC objective score, the Tegner activity scale and the Lysholm score. RESULTS: Initial CT scans revealed mean tunnel volumes of 3.8cm3 (±2.7) femoral and 6.1cm3 (±2.4) tibial. Filling rates of 76.1% (±12.4) femoral and 87.4% (±5.9) tibial were achieved. Postoperative radiographs revealed significantly improved tunnel positioning with anatomical placement in all but one case at the femur and in all cases at the tibia. At follow up, patients showed significantly improved anterior tibial translations with residual side-to-side differences of 1.7 mm (±0.8) and significantly improved IKDC objective scores. Furthermore, significantly higher values were achieved on the Tegner activity scale (5.3 ± 1.4 vs. 2.8 ± 0.5) and the Lysholm score (85.4 ± 7.9 vs. 62.5 ± 10.5) compared to the preoperative status. CONCLUSION: Autologous RIA harvested bone grafting ensures sufficient bone stock consolidation allowing for anatomical tunnel placement of the subsequently conducted revision ACL reconstruction. The two-staged procedure reliably restores stability and provides satisfying subjective and objective outcomes. Thus, RIA harvested bone grafting is an eligible alternative to autologous iliac crest or allogenic bone grafting.

Release behavior of VAN from four types of CaP-ceramic granules using various loading methods at two different degrees of acidity.

The release behavior of vancomycin (VAN) from beta-tricalciumphosphate (ßTCP), hydroxyapatite (HA), glass ceramic (GC) and sponge-like collagen ßTCP granule composite (sponge) was studied. Vacuum and drip loading methods were compared. The influence of VAN concentration and pH on release behavior was analyzed with respect to a stable release level of VAN above the minimum inhibitory concentration over 14 days. Initially the morphology of the granule carrier systems was examined with ESEM, stereomicroscopy, µCT-imaging and Camsizer® regarding porosity, interconnecting pores and granule size. Drug release patterns following a vacuum and a drip loading method with VAN at concentrations of 5 and 50 mg/ml were compared. The influence of pH 7.4 compared to pH 5.0 on release behavior was studied. The drug was released in bidistilled water at 37 °C, the concentration determined by photometry at 220 nm. For statistical purposes, the mean and standard deviation were calculated and analyzed by Origin 9.1 Professional SR1 (OriginLab). Due to low interconnectivity and low porosity, the vacuum loading method was unable to attain complete drug loading of the ceramic granules. The sponge showed an inhomogeneous distribution of ßTCP granules. Drug release was high at pH 7.4, at pH 5.0 it practically did not occur. All samples except for the collagen-complex show an initial VAN burst release with a following steady release. Loading with 5 mg/ml concentrated VAN resulted in a higher percentage of available drug being released. However, when loaded with 50 mg/ml, the absolute amount of drug released was higher.

Functional outcome after transphyseal anterior cruciate ligament reconstruction in young patients with open growth plates.

BACKGROUND: This study evaluates sports ability, rotational laxity and potential growth changes in children after transphyseal ACL reconstruction with metaphyseal fixation technique, considering physis biology by placing drill holes vertically in the femoral anatomic origin in order to reduce volumetric injury to the physis. METHODS: In this retrospective trial of 42 patients data were collected. Thirty-seven were reviewed measuring rotational laxity and anteroposterior tibial translation using the Laxitester (ORTEMA Sport Protection, Markgroeningen, Germany) and the KT1000. Clinical examination was evaluated with the IKDC 2000 knee examination form. Leg axis was determined with digital photography and leg length was assessed clinically. Sports ability was assessed with questionnaires including subjective IKDC, Tegner Activity Scale, Activity Rating Scale and a questionnaire on sports and level of sports. RESULTS: Mean follow-up was 24.9months. Mean age at surgery was 13.2years in boys and 13.1years in girls. IKDC 2000 grading was A or B in 28 patients and C in nine patients. Significant increased anterior tibial translation was observed in neutral position and in external tibia rotation. No growth abnormalities were seen. Fifty-seven percent of the patients were able to participate in competitive sports at follow-up. CONCLUSION: Transphyseal ACL reconstruction with metaphyseal fixation in children with open growth plates can be done with low risk of growth changes. Return to competitive sports is possible although low rotational laxity still exists. LEVEL OF EVIDENCE: IV.

[Complications of knee arthroscopy]. / Komplikationen arthroskopischer Eingriffe am Kniegelenk.

BACKGROUND: Today, knee arthroscopy is one of the standard interventions performed by an orthopaedist and usually has a low potential for complications. PURPOSE: The surgeon should still be aware of possible problems, and be able to control and explain them to the patient in detail before surgery. MATERIALS AND METHODS: The possible relevant peri-, intra- and postoperative complications of knee arthroscopy are discussed. RESULTS: Evaluation of the patient's medical history and comorbidities is crucial to successful treatment, in addition to a correct diagnosis and indications with the assistance of appropriate imaging procedures. Nervous and vascular injuries, malplacement of arthroscopy portals, thrombosis, air embolism, material breakage and a possible compartment syndrome constitute the peri-and intraoperative complications. Postoperatively, the most frequent negative events are haemarthrosis, thrombosis, embolism and infection, and the appearance of synovial fistulas. In the case of a joint infection, consistent and immediate diagnosis and therapy are vital for joint preservation. Late complications after arthroscopic interventions include Ahlback's disease, arthrofibrosis and complex regional pain syndrome (CRPS). DISCUSSION: Nowadays, the systematic education of arthroscopic surgeons using simulators, models, and cadavers, in addition to shadowing experienced arthroscopists, is required to offer patients the best therapeutic options.

[Management of Flexion Contracture in Primary Total Knee Arthroplasty]. / Umgang mit der Beugekontraktur in der primären Knieendoprothetik.

Flexion contracture is a common deformity of the arthritic knee. The present publication describes causes, clinical relevance and surgical technique in the presence of flexion contractures in total knee arthroplasty. Flexion contracture can be attributed to different causes. Basically it is a mismatch between flexion and extension gaps. Moderate and severe deformities have to be corrected by additional surgical interventions. In most cases soft tissue techniques with release of contracted structures, the removal of osteophytes and additional distal femoral bone resection are necessary. The goal of these interventions is to achieve full extension of the knee. During rehabilitation attention has to be paid to maintain it with intensive physical therapy. A remaining flexion contracture is associated with inferior functional outcome and persistent pain.

[Defect Reconstruction in Total Knee Arthroplasty with wedges and blocks]. [Corrected]. / Defektrekonstruktion in der Knieendoprothetik mit Wedges und Blöcken.

OBJECTIVE: Surgical technique for primary and revision total knee arthroplasty to reconstruct bone defects with metal augments and reproducible positioning of the implant at the right joint line. INDICATIONS: Primary and revision total knee arthroplasty with bone defects. CONTRAINDICATIONS: Complete destruction of the metaphysis. SURGICAL TECHNIQUE: Implantation of revision components performed in three consecutive steps: first, positioning of the tibia component at correct height and rotation; second, determination of the posterior joint line in flexion through the size and correct rotation of the femoral implant; third, determination of the distal joint line by use of positioning of the femoral component. These steps are performed independently from bone defects, which are subsequently reconstructed with metal augments. POSTOPERATIVE MANAGEMENT: Mobilization with weight bearing and range of motion as tolerated, depending on osseous and soft tissue condition at primary or revision surgery. RESULTS: In a prospective study, 132 consecutive knee revisions in 76 women and 56 men with an average age of 72.4 years (range 49-93 years) were followed up clinically and radiologically preoperatively and at a mean follow-up of 74 months (range 38-105 months). Clinical results were based on the American Knee Society score. The score was 46.3 (range 31-65) preoperatively and 82.5 (range 61-96) at follow-up. Radiologically 12.1 % of the knees showed lysis around the augment with no clinical signs of loosening. No revisions were performed due to aseptic loosening. The joint line was correctly reconstructed in 84.8 %.

[Arthroscopic treatment of arthrofibrosis after ACL reconstruction. Local and generalized arthrofibrosis]. / Arthroskopische Arthrolyse bei Arthrofibrose nach Ersatzplastik des vorderen Kreuzbandes. Lokale und generalisierte Arthrofibrose.

OBJECTIVE: Restoration of free knee motion taking into account knee extension, knee flexion, and patella mobility. INDICATIONS: Prolonged knee motion restriction after anterior cruciate ligament (ACL) reconstruction, persistent decreased patella mobility, or extension deficit. CONTRAINDICATIONS: Existing significant joint irritation or active reflex dystrophy with persistent distinctive pain syndrome. SURGICAL TECHNIQUE: Arthroscopic arthrolysis possible in most cases. Removal of adhesions in all compartments. Elimination of intraarticular cause of patella infera by removing infrapatellar scar tissue and fibrotic fat pad. In case of severe peripatellar fibrotic tissue, lateral release is useful with partial transection of lateral retinacula. In case of strong capsular contracture, additional medial release indicated to improve patella mobility. Important goal of arthrolysis: full range of knee extension. Arthrolysis for scar tissue removal in the posterior recessus through dorsomedial arthroscopic approach possible. In severe cases posteromedial arthrotomy for posterior capsule release required. Cyclops syndrome makes removal of all tissue adherent to the ACL necessary. An irregular ACL insertion or intercondylar notch stenosis may require notchplasty. Postoperative recurrence of fibrosis may require repeated arthroscopic surgery to improve mobility, such as notchplasty, osteophytes resection, scar removal, and releases. POSTOPERATIVE MANAGEMENT: Immediate postoperative pain-free physical therapy taking into account full range of extension and patella mobility. Passive exercises under traction. Lymphatic drainage. No exercising in pain throughout the entire postoperative physical therapy. Continuous passive motion treatment for 4 weeks postoperatively useful. No muscle strength or equipment training for at least 3 months postoperatively. RESULTS: Based on the observations in our working group, approximately pproximately 78% of patients develop knee osteoarthritis within 5 years.

[Early results of gender-specific posterior stabilized total knee arthroplasty without patella resurfacing]. / Konventionelle und geschlechtsspezifische kreuzbandersetzende Knietotalendoprothesenimplantation. Vergleich frühfunktioneller Ergebnisse.

INTRODUCTION: To address anatomical gender differences in total knee arthroplasty (TKA) specific total knee prostheses have been developed for women. Potential benefits of these modified prostheses are currently under debate. The present study investigated whether the modified design features bring benefits compared to uni-sex TKA. METHODS: A total of 80 prospectively blinded and randomized patients underwent implantation of unilateral TKAs with NexGen LPS Gender Solutions (Zimmer, Warsaw, USA, group gender-specific GS prosthesis, n = 40) or NexGen LPS Flex (Zimmer, Warsaw, USA, control group standard prosthesis ST, n = 40) The follow-up was carried out 10 days and 6 weeks postoperatively. Clinical data and the subjective assessment of quality of life were evaluated using the Knee Society Clinical Rating System (KSS), the short form 36-item health survey (SF-36) and the Western Ontario and McMaster Universities OA Index (WOMAC). RESULTS: The two groups showed equal values in KSS, SF-36 and WOMAC preoperatively and ten days postoperatively the GS group reached an average KSS knee score of 62.6 ± 16.1 points (ST group 56.9 ± 14.7, p = 0.184) and a functional score of 28.5 ± 12.1 (ST group 24.3 ± 15.3, p = 0.082). In the overall score the GS group reached 91.1 ± 24.1 points (ST group 81.0 ± 27.1, p = 0.104). The GS group reached a knee score of 85.5 ± 14.4 points (ST group 77.8 ± 16.8, p = 0.03) and a functional score of 68.1 ± 20.7 points (ST group 62.3 ± 18.5, p = 0.185) 6 weeks postoperatively. In the overall score the GS group reached 153.7 ± 30.7 points (ST group 139.6 ± 32.4, p = 0.048). The analysis of SF-36 and WOMAC showed no significant differences at all time points. No evidence of loosening or migration was observed in both groups. CONCLUSIONS: Based on the data presented, gender-specific TKA type NexGen LPS Gender Solutions has advantages in terms of early functional outcome. This result is not reflected in the patient satisfaction and is not considered to be clinically relevant.

Microporous calcium phosphate ceramics as tissue engineering scaffolds for the repair of osteochondral defects: Histological results.

Treatment of defects in joint cartilage aims to re-establish normal joint function. In vitro experiments have shown that the application of synthetic scaffolds is a promising alternative to existing therapeutic options. A sheep study was conducted to test the suitability of microporous pure ß-tricalcium phosphate (TCP) ceramics as tissue engineering scaffolds for the repair of osteochondral defects. Cylindrical plugs of microporous ß-TCP (diameter: 7mm; length: 25mm; porosity: 43.5±2.4%; pore diameter: ~5µm) with interconnecting pores were used. Scaffolds were seeded with autologous chondrocytes in vitro and cultured for 4weeks. A drill hole (diameter 7mm) was placed in both medial femoral condyles of sheep. For the left knee the defect was filled with a TCP plug and for the right knee the defect was left empty. After 6, 12, 26 and 52weeks, seven animals from each group were killed and studied. The samples were examined employing histological, histomorphometric and immunohistological methods as well as various imaging techniques (X-ray, microcomputer tomography and scanning electron microscopy). After explantation the cartilage defects were first assessed macroscopically. There were no signs of infection or inflammation. Histological grading scales were used for assessment of bony integration and cartilage repair. An increasing degradation (81% after 52weeks) of the ceramic with concomitant bone formation was observed. The original structure of cancellous bone was almost completely restored. After 26 and 52weeks, collagen II-positive hyaline cartilage was detected in several samples. New subchondral bone had formed. The formation of cartilage began at the outer edge and proceeded to the middle. According to the O'Driscoll score, values corresponding to healthy cartilage were not reached after 1year. Integration of the newly formed cartilage tissue into the surrounding native cartilage was found. The formation of biomechanical stable cartilage began at the edge and progressed towards the centre of the defect. After 1year this process was still not completed. Microporous ß-TCP scaffolds seeded with chondrocytes are suitable for the treatment of osteochondral defects.

Microporous calcium phosphate ceramics as tissue engineering scaffolds for the repair of osteochondral defects: biomechanical results.

This work investigated the suitability of microporous ß-tricalcium phosphate (TCP) scaffolds pre-seeded with autologous chondrocytes for treatment of osteochondral defects in a large animal model. Microporous ß-TCP cylinders (Ø 7 mm; length 25 mm) were seeded with autologous chondrocytes and cultured for 4 weeks in vitro. Only the upper end of the cylinder was seeded with chondrocytes. Chondrocytes formed a multilayer on the top. The implants were then implanted in defects (diameter 7 mm) created in the left medial femoral condyle of ovine knees. The implants were covered with synovial membrane from the superior recess of the same joint. For the right knees, an empty defect with the same dimensions served as control. Twenty-eight sheep were split into 6-, 12-, 26- and 52 week groups of seven animals. Indentation tests with a spherical (Ø 3mm) indenter were used to determine the biomechanical properties of regenerated tissue. A software-based limit switch was implemented to ensure a maximal penetration depth of 200 µm and maximal load of 1.5 N. The achieved load, the absorbed energy and the contact stiffness were measured. Newly formed cartilage was assessed with the International Cartilage Repair Society Visual Assessment Scale (ICRS score) and histomorphometric analysis. Results were analysed statistically using the t-test, Mann-Whitney U-test and Wilcoxon test. Statistical significance was set at p<0.05. After 6 weeks of implantation, the transplanted area tolerated an indentation load of 0.05±0.20 N. This value increased to 0.10±0.06 N after 12 weeks, to 0.27±0.18 N after 26 weeks, and 0.27±0.11 N after 52 weeks. The increase in the tolerated load was highly significant (p<0.0001), but the final value was not significantly different from that of intact cartilage (0.30±0.12 N). Similarly, the increase in contact stiffness from 0.87±0.29 N mm-(1) after 6 weeks to 3.14±0.86 N mm(-1) after 52 weeks was highly significant (p<0.0001). The absorbed energy increased significantly (p=0.02) from 0.74×10(-6)±0.38×10(-6) Nm after 6 weeks to 2.83×10(-6)±1.35×10(-6) Nm after 52 weeks. At 52 weeks, the International Cartilage Repair Society (ICRS) scores for the central area of the transplanted area and untreated defects were comparable. In contrast, the score for the area from the edge to the centre of the transplanted area was significantly higher (p=0.001) than the score for the unfilled defects. A biomechanically stable cartilage was built outside the centre of defect. After 52 weeks, all but one empty control defect were covered by bone and a very thin layer of cartilage (ICRS 7 points). The empty hole could still be demonstrated beneath the bone. The histomorphometric evaluation revealed that 81.0±10.6% of TCP was resorbed after 52 weeks. The increase in TCP resorption and replacement by spongy bone during the observation period was highly significant (p<0.0001). In this sheep trial, the mechanical properties of microporous TCP scaffolds seeded with transplanted autologous chondrocytes were similar to those of natural cartilage after 52 weeks of implantation. However, the central area of the implants had a lower ICRS score than healthy cartilage. Microporous TCP was almost fully resorbed at 52 weeks and replaced by bone.

Adhesion and proliferation of human osteoblast-like cells on different biodegradable implant materials used for graft fixation in ACL-reconstruction.

INTRODUCTION: This study investigates the adhesion and proliferation behaviour of human osteoblast-like cells over time when incubated on surfaces of biodegradable screws and pins used for graft fixation in ACL reconstruction. MATERIALS AND METHODS: 2 mm-sized-wedges of four bioresorbable implants [1. poly-L-lactide acid (PLLA) screw, 2. PLLA/ß-tricalciumphosphate (PLLA/TCP) (70 %/30 %) screw, 3. poly-L-lactide-co-glycolic acid/ß-tricalciumphosphate (PLGA/TCP) (70 %/30 %) screw and 4. PLLA pin] were incubated with human osteoblast-like cells. All probes were evaluated after 3,7,14 and 21 days by cell number count, determination of cell proliferation, observation of cell adhesion of human osteoblast-like cells under an environmental scanning electron microscope (ESEM), and by a live-dead assay. RESULTS: Cell numbers were lower at all stages in both PLLA groups compared to the composite materials (PLLA/TCP and PLGA/TCP). A significant difference in cell proliferation was found after 21 days. The cells on both composite screws (PLLA/TCP and PLGA/TCP) maintained more contact points with the screw surface compared to the cells on PLLA screws under ESEM. No cytotoxicity could be observed in the live-dead assay. DISCUSSION: Mainly, ß-TCP as part of a composite implant seems to offer good ultrastructural properties for cell adhesion according to our in vitro study. Cell numbers seem to be influenced by the degradation behaviour with higher cell numbers in the composite groups.

[Extension first technique for TKA implantation]. / Die Extension-First-Technik bei der Knie-TEP-Implantation.

OBJECTIVE: Surgical technique in total knee arthroplasty (TKA) to combine the femur first and tibia first techniques in order to reduce surgical mistakes regarding rotation and alignment. INDICATIONS: Symptomatic arthritis of the knee. CONTRAINDICATIONS: General contraindications for TKA. SURGICAL TECHNIQUE: Osseous preparation starting with a distal femur cut. Then the proximal tibia cut is accomplished and the knee is balanced in extension after checking for correct alignment. Bone-referenced positioning of the femoral cutting block for further preparation of the femur. Finally, the rotation of the femur is checked in 90° of flexion by means of ligament tension. If required, the rotation is checked and the flexion gap balanced, respectively. POSTOPERATIVE MANAGEMENT: Mobilization with weight bearing and range of motion as tolerated. RESULTS: In a prospective study, 267 knees (160 women, 107 men, average age of 69.3 [46-89] years) were followed up preoperatively and after 6 weeks. The clinical results were based on the American Knee Society score. The scores were 48.9 (32-68) preoperatively and 86.5 (75-100) at follow-up. Radiologically 92.1% of the knees showed a malposition <3°.

[TKA revision of semiconstraint components using the 3-step technique]. / Knie-TEP-Revision auf ein halbgekoppeltes Prothesensystem mit der 3-Schritt-Technik.

OBJECTIVE: The surgical goal is to achieve a pain free and stable knee joint after revision total knee arthroplasty in three steps. An important component of the technique is the reproducible restoration of the joint line. INDICATIONS: Revision total knee arthroplasty. CONTRAINDICATIONS: Complete bone loss at the knee joint (epicondyles and tibia plateau), persistent joint infection, loss of the extension apparatus, and neurological disease with progressive ligament instability. SURGICAL TECHNIQUE: Implantation of revision components is performed in three steps. The first step is the positioning of the tibia component at the correct height and rotation. As the position of the tibial articular surface is independent of the knee position, the tibia serves as a reference both in extension and in flexion. The second step consists of balancing the knee joint in flexion and, thereby, definition of the flexion gap and the rotation of the femoral component. In the third step, the reconstruction and balancing of the knee joint in extension is performed. POSTOPERATIVE MANAGEMENT: Mobilization with weight bearing and range of motion as tolerated depending on osseous and soft tissue condition at surgery. The surgical technique does not influence the further treatment. RESULTS: In a prospective study, 168 consecutive knee revisions operated by the first author were examined clinically and radiologically preoperatively and at a mean follow-up of 38 months (range 22-61 months). There were 96 knees from women and 72 were from men with an average age of 74.6 years (range 51-92 years). Clinical results were based on the American Knee Society score. The score showed 47.6 (range 32-63) preoperatively and 81.5 (range 62-95) at follow-up. Radiologically, 92.7% of the knees showed a malposition <3°. The joint line was correctly reconstructed in 86.3% based on the preoperative plan; 89% of the patella showed correct tracking in the patella tangential view.

Cartilage repair approach and treatment characteristics across the knee joint: a European survey.

INTRODUCTION: To describe indication, approach and treatment modalities for the management of knee cartilage lesions among a selected European population. METHODS: An electronic questionnaire covering general and specific items concerning cartilage repair at the knee joint was designed and disposed to survey cartilage treatment characteristics among a defined population of trained and accredited musculoskeletal surgeons. RESULTS: A total of 242 (80.13%) interviewees returned the questionnaire. Two-thirds of the respondents considered patient age to not limit (33.1%) or considered the age of 50 as the upper limit (32.2%) for interventional cartilage surgery. There was no consensus on when to correct mechanical axis deformation. Irrespective of lesion size, surgical debridement and microfracture are the techniques most frequently used. Surgical approach to full-thickness cartilage defects is commenced when the lesion size exceeds 1 cm(2) in 75.6% of respondents; mainly utilizing microfracture or debridement for defects smaller than 1, 2 and 3 cm(2). Controversy exists for treatment of lesions exceeding 3 cm(2), where autologous chondrocyte transplantation is utilized in the majority of cases (33.5%), while as well microfracture (19.0%) and with lesser frequency osteochondral plug (9.5%) transplantation are recommended. Debridement was indicated to be used in combination with other techniques, while microfracture, chondrocyte or osteochondral plug transplantation are applied as individual techniques. CONCLUSIONS: Microfracture with debridement are the two most frequently used operations in lesions up to 3 cm(2). There remains disagreement when indicating cartilage repair when age, mechanical axis deviation or treatment of lesions over 3 cm(2) are concerned.

[Analyses and comparison of 2-D vs. 3-D glenoid versions in atraumatic/traumatic shoulder instability--are 3-D analyses essential?]. / Analyse und Vergleich 2-D- vs. 3-D-Glenoidversion bei a-/traumatischer Schulterinstabilität--ist eine 3-D-Analyse notwendig?

AIM: Changes in glenoid orientation as a primary cause of shoulder instability have been discussed controversially in the literature. The data of a physiological glenoid version vary widely among different authors and techniques. One reason may be that the previously used 2-D techniques suffer from a limited reproducibility and validity. The objective of this study was therefore to compare the 2-D and 3-D analyses of the glenoid version in patients with shoulder instability. METHOD: The shoulders of 28 healthy volunteers and of 14 patients each with atraumatic/traumatic instability were examined in an open MR scanner (0.2 T). The 2-D glenoid version was determined using post-processing techniques according to the technique of Friedman et al. (1992). Afterwards, the 3-D glenoid version was analysed independently of the slice orientation and patient position. The coefficient of correlation (r) between the 2-D and 3-D glenoid versions was calculated using the correlation z test. RESULTS: The 3-D post-processing technique showed a reproducibility with a coefficient of variation of 8.3 %. Patients with traumatic instability demonstrated no significant difference compared to the healthy control group (4.4 +/- 2.1 degrees vs. healthy: 3.9 +/- 1.3 degrees). In atraumatic shoulder instability the glenoid retroversion was in the mean significantly increased (10.2 +/- 4.9 degrees). The individual values ranged between 2.6 degrees and 16.6 degrees . Also for the contralateral, unaffected side a significantly increased retroversion (6.3 +/- 2.2 degrees) was observed compared to healthy shoulders. There was a significant correlation (r: 0.84) between 2-D and 3-D retroversion. CONCLUSIONS: The presented techniques allow for a reproducible assessment of glenoid version independent of the slice orientation and patient position. Our results demonstrate in the mean only a small difference of +/- 3 degrees between 2-D and 3-D glenoid versions. Therefore under standardised conditions the 2-D CT/MRI should be adequate for measuring the glenoid version except for borderline cases. No significant changes in glenoid version were found in patients with traumatic instability. In atraumatic, posterior instability, in the mean an increased retroversion was observed on both sides. However, the magnitude of these changes varied widely among individuals and should be identified to initiate a causal treatment.