Hendrik Kohlhof

Mid-term results of transphyseal anterior cruciate ligament reconstruction in children and adolescents

BACKGROUND Optimal therapy for anterior cruciate ligament (ACL) rupture in the paediatric population still provokes controversy. Although conservative and operative treatments are both applied, operative therapy is slightly favored. Among available surgical techniques are physeal-sparing reconstruction and transphyseal graft fixation. The aim of this study was to present our mid-term results after transphyseal ACL reconstruction. METHODS Fifteen young patients (mean age=12.8±2.6, range=6.2-15.8 years, Tanner stage=2-4) with open physis and traumatic anterior cruciate rupture who had undergone transphyseal ACL reconstruction with unilateral quadriceps tendon graft were prospectively analyzed. All children were submitted to radiological evaluation to determine the presence of clearly open growth plates in both the distal femur and proximal tibia. Postoperatively, all patients were treated according to a standardized rehabilitation protocol and evaluated by radiographic analysis and the Lysholm-Gillquist and IKDC 2000 scores. Their health-related quality of life was measured using the SF-12 PCS (physical component summary) and MCS (mental component summary) questionnaires. RESULTS Mean postoperative follow-up was 4.1 years. Mean Lysholm-Gillquist score was 94.0. Thirteen of the 15 knees were considered nearly normal on the IKDC 2000 score. The mean SF-12 questionnaire score was 54.0±4.8 for SF-12 PCS and 59.1±3.7 for SF-12 MCS. No reruptures were observed. Radiological analysis detected one knee with valgus deformity. All patients had a normal gait pattern without restrictions. CONCLUSION Transphyseal reconstruction of the anterior cruciate ligament shows satisfactory mid-term results in the immature patient.

An intraoperatively moulded PMMA prostheses like spacer for two-stage revision of infected total knee arthroplasty

We report a series of 16 consecutive total knee arthroplasty (TKA) revision procedures for deep infection, treated with a newly developed intraoperatively moulded PMMA cement-prostheses-like spacer (CPLS). The standard treatment consisted of a two-stage protocol with initial explantation of the infected components combined with radical debridement, followed by implantation of a temporary cement spacer and final reimplantation of a new TKA. A sterilizeable Teflon tapered aluminium mould was developed for production of a custom made CPLS during the intervention. Stable implantation of the CPLS was achieved with a second cementation, allowing for correct alignment and ligament balancing. The spacer remained 3.5 months on average until reimplantation of a TKA occurred. At time of reimplantation, patients had an average KSS score of 84.44 points with an average flexion capacity of 102°. There was no recurrent infection during the study period of minimum 2 years. With this new technique, a low friction articulation with good stability, high comfort and a better range of motion compared to handcrafted spacers was achieved. The use of this spacer is a time sparing, cheap and convenient option in 2-stage TKA revision.

Cement-augmented anterior screw fixation of Type II odontoid fractures in elderly patients with osteoporosis.

BACKGROUND CONTEXT Closed reduction and internal fixation by an anterior approach is an established option for operative treatment of displaced Type II odontoid fractures. In elderly patients, however, inadequate screw purchase in osteoporotic bone can result in severe procedure-related complications. PURPOSE To improve the stability of odontoid fracture screw fixation in the elderly using a new technique that includes injection of polymethylmethacrylat (PMMA) cement into the C2 body. STUDY DESIGN Retrospective review of hospital and outpatient records as well as radiographs of elderly patients treated in a university hospital department of orthopedic surgery. PATIENT SAMPLE Twenty-four elderly patients (8 males and 16 females; mean age, 81 years; range, 62-98 years) with Type II fractures of the dens. OUTCOME MEASURES Complications, cement leakage (symptomatic/asymptomatic), operation time, loss of reduction, pseudarthrosis and revision surgery, patient complaints, return to normal activities, and signs of neurologic complications were all documented. METHODS After closed reduction and anterior approach to the inferior border of C2, a guide wire is advanced to the tip of the odontoid under biplanar fluoroscopic control. Before the insertion of one cannulated, self-drilling, short thread screws, a 12 gauge Yamshidi cannula is inserted from anterior and 1 to 3 mL of high-viscosity PMMA cement is injected into the anteroinferior portion of the C2 body. During polymerization of the cement, the screws are further inserted using a lag-screw compression technique. The cervical spine then is immobilized with a soft collar for 8 weeks postoperatively. RESULTS Anatomical reduction of the dens was achieved in all 24 patients. Mean operative time was 64 minutes (40-90 minutes). Early loss of reduction occurred in three patients, but revision surgery was indicated in only one patient 2 days after primary surgery. One patient died within the first eight postoperative weeks, one within 3 months after surgery. In five patients, asymptomatic cement leakage was observed (into the C1-C2 joint in three patients, into the fracture in two). Conventional radiologic follow-up at 2 and 6 months confirmed anatomical healing in 16 of the 19 patients with complete follow-up. In two patients, the fractures healed in slight dorsal angulation; one patient developed a asymptomatic pseudarthrosis. All patients were able to resume their pretrauma level of activity. CONCLUSIONS Cement augmentation of the screw in Type II odontoid fractures in elderly patients is technically feasible in a clinical setting with a low complication rate. This technique may improve screw purchase, especially in the osteoporotic C2 body.

RANK-ligand and osteoprotegerin as biomarkers in the differentiation between periprosthetic joint infection and aseptic prosthesis loosening

AIM To assess serum levels of RANK-ligand (RANKL) and osteoprotegerin (OPG) as biomarkers for periprosthetic joint infection (PJI) and compare their accuracy with standard tests. METHODS One hundred and twenty patients presenting with a painful total knee or hip arthroplasty with indication for surgical revision were included in this prospective clinical trial. Based on standard diagnostics (joint aspirate, microbiological, and histological samples) and Musculoskeletal Infection Society consensus classification, patients were categorized into PJI, aseptic loosening, and control groups. Implant loosening was assessed radiographically and intraoperatively. Preoperative serum samples were collected and analyzed for RANKL, OPG, calcium, phosphate, alkaline phosphatase (AP), and the bone-specific subform of AP (bAP). Statistical analysis was carried out, testing for significant differences between the three groups and between stable and loose implants. RESULTS All three groups were identical in regards to age, gender, and joint distribution. No statistically significant differences in the serum concentration of RANKL (P = 0.16) and OPG (P = 0.45) were found between aseptic loosening and PJI, with a trend towards lower RANKL concentrations and higher OPG concentrations in the PJI group. The RANKL/OPG ratio was significant for the comparison between PJI and non-PJI (P = 0.005). A ratio > 60 ruled out PJI in all cases (specificity: 100%, 95%CI: 89, 11% to 100.0%) but only 30% of non-PJI patients crossed this threshold. The positive predictive value remained poor at any cut-off. In the differentiation between stable and loose implants, none of the parameters measured (calcium, phosphate, AP, and bAP) showed a significant difference, and only AP and bAP measurements showed a tendency towards higher values in the loosened group (with P = 0.09 for AP and P = 0.19 for bAP). CONCLUSION Lower RANKL and higher OPG concentrations could be detected in PJI, without statistical significance.

Single Molecule Microscopy Reveals an Increased Hyaluronan Diffusion Rate in Synovial Fluid from Knees Affected by Osteoarthritis.

Osteoarthritis is a common and progressive joint disorder. Despite its widespread, in clinical practice only late phases of osteoarthritis that are characterized by severe joint damage are routinely detected. Since osteoarthritis cannot be cured but relatively well managed, an early diagnosis and thereby early onset of disease management would lower the burden of osteoarthritis. Here we evaluated if biophysical parameters of small synovial fluid samples extracted by single molecule microscopy can be linked to joint damage. In healthy synovial fluid (ICRS-score < 1) hyaluronan showed a slower diffusion (2.2 μm2/s, N = 5) than in samples from patients with joint damage (ICRS-score > 2) (4.5 μm2/s, N = 16). More strikingly, the diffusion coefficient of hyaluronan in healthy synovial fluid was on average 30% slower than expected by sample viscosity. This effect was diminished or missing in samples from patients with joint damage. Since single molecule microscopy needs only microliters of synovial fluid to extract the viscosity and the specific diffusion coefficient of hyaluronan this method could be of use as diagnostic tool for osteoarthritis.

The Cement Prosthesis-Like Spacer: An Intermediate Halt on the Road to Healing

Background. Periprosthetic infections remain a devastating problem in the field of joint arthroplasty. In the following study, the results of a two-stage treatment protocol for chronic periprosthetic infections using an intraoperatively molded cement prosthesis-like spacer (CPLS) are presented. Methods. Seventy-five patients with chronically infected knee prosthesis received a two-stage revision procedure with the newly developed CPLS between June 2006 and June 2011. Based on the microorganism involved, patients were grouped into either easy to treat (ETT) or difficult to treat (DTT) and treated accordingly. Range of motion (ROM) and the knee society score (KSS) were utilized for functional assessment. Results. Mean duration of the CPLS implant in the DTT group was 3.6 months (range 3–5 months) and in the ETT group 1.3 months (range 0.7–2.5 months). Reinfection rates of the final prosthesis were 9.6% in the ETT and 8.3% in the DTT group with no significant difference between both groups regarding ROM or KSS (P = 0.87, 0.64, resp.). Conclusion. The results show that ETT patients do not necessitate the same treatment protocol as DTT patients to achieve the same goal, emphasizing the need to differentiate between therapeutic regimes. We also highlight the feasibility of CLPS in two-stage protocols.

Detection of Pantoea agglomerans in hip prosthetic infection by sonication of the removed prosthesis: The first reported case

Pantoea agglomerans is a rare isolate in orthopaedic patients. We describe the first case of an acute hip prosthetic joint infection (PJI) caused by Pantoea agglomerans. The microorganism was detected after sonication of the removed hip endoprosthesis.

An aluminium mold for intraoperative production of antibiotic-loaded PMMA knee prostheses

For treatment of total knee prosthesis infections, a two-stage protocol with explantation of the infected components, antibiotic cement spacer implantation, and secondary reimplantation of the prosthesis after curing the infection is the accepted standard procedure (Wilde and Ruth 1988, Pitto and Spika 2004). The cement spacer is antibiotic-loaded, maintains the articular distance between femur and tibia, stabilizes the knee, and allows passive motion of the knee (Scott et al. 1993). Different techniques have been used for fabrication of this spacer, including intraoperative molding. The results of handcrafted spacers are unsatisfactory because such spacers have a rough surface and are not congruent. As a result, instability, limited range of motion, and excessive wear have been reported (Goksan and Freeman 1992, Hanssen et al. 1994). We have developed a tapered aluminium mold for production of a custom made PMMA spacer like prostheses (CLSP) during the intervention. We consider the use of the CSLP as a promising approach for the treatment of complicated deep TKA infections since this technique is time sparing, cheap and easy to apply in all surgical theatres. Construction of the spacer mold The 2 molds were produced in a computerized numerical-control sinking machine (DMU 70eV-process) based on the design of the balanSys knee system (size B; D) (Mathys AG, Bettlach, Switzerland). The mold for the femoral spacer consists of 3 parts and for the tibial spacer, of 2. It is made of high-strength aluminium (AA7075 T6 3.4365; density 2.8 kg/dm3 and tensile strength 520–560 Nm/mm2) and coated with Altef. In this process, the surface of the base material is converted into a ceramic coating in which Teflon is integrated. Half of the coating penetrates into the base material, which results in an increase of 25 µm, leading to a standard coating thickness of 50 µm. The mold can be cleaned and sterilized for re-use (Figure 1 and ​and22). Figure 3. Implantation of the intraoperative molded PMMA knee spacer. Figure 1. Femoral mold, composed of 3 parts. It can be filled through 2 channels with tubes. Figure 2. The 2 parts of the tibial mold. Surgical technique and postoperative protocol The first step includes explantation of the prosthetic components and removal of the cement mantle. An extensive debridement of the infected joint is performed. Biopsies are taken for microbiological culture and histology. The appropriate size for the components is assessed on conventional AP and lateral knee radiographs. The parts of the femoral mold component are mounted with 2 screws. If necessary, special antibiotics can be added to the cement, based on the cultures and antibiogram. The mold is filled through 2 channels on the upper side, using a 20-mL tube. After polymerization of the cement, the screws, which interlink the mold, are opened and the femoral spacer component can be easily removed from the mold. Since the cement expands during polymerization, pressure inside the closed mold rises and creates a smooth surface on the final cement spacer. The femoral component is implanted first with a small portion of additional cement. Then the distance between the tibia and the femur is measured in neutral position. The tibial mold is filled with PMMA cement according to the distance measured. After polymerization of the cement, the tibial part of the spacer is removed from the mold and the mounting cement on the posterior and lateral side of the spacer is removed with a Luer pincer. The tibial component is then implanted with a small portion of cement (Figure 3). The stability and range of motion is tested, and then the wound can be closed (Figures 4). Figure 4. After implantation of the PMMA spacer. Depending on the agent and the intraoperative findings, an individual protocol of intravenous and oral antibiotics is indicated. Continuous passive motion is started 24 h postoperatively, with no limitations. Ambulation is started (with two crutches and partial weight bearing of 20 kg) on the third day after surgery.

Indication Criteria for Total Knee Arthroplasty in Patients with Osteoarthritis – A Multi-perspective Consensus Study

Background and Objectives Knee osteoarthritis (OA) is a significant public health burden. Rates of total knee arthroplasty (TKA) in OA vary substantially between geographical regions, most likely due to the lack of standardised indication criteria. We set out to define indication criteria for the German healthcare system for TKA in patients with knee OA, on the basis of best evidence and transparent multi-stakeholder consensus. Methods We undertook a complex mixed methods study, including an iterative process of systematic appraisal of existing evidence, Delphi consensus methods and stakeholder conferences. We established a consensus panel representing key German national societies of healthcare providers (orthopaedic surgeons, rheumatologists, pain physicians, psychologists, physiotherapists), payers, and patient representatives. A priori defined consensus criteria were at least 70% agreement and less than 20% disagreement among the consensus panel. Agreement was sought for (1) core indication criteria defined as criteria that must be met to consider TKA in a normal patient with knee OA, (2) additional (not obligatory) indication criteria, (3) absolute contraindication criteria that generally prohibit TKA, and (4) risk factors that do not prohibit TKA, but usually do not lead to a recommendation for TKA. Results The following 5 core indication criteria were agreed within the panel: 1. intermittent (several times per week) or constant knee pain for at least 3 - 6 months; 2. radiological confirmation of structural knee damage (osteoarthritis, osteonecrosis); 3. inadequate response to conservative treatment, including pharmacological and non-pharmacological treatment for at least 3 - 6 months; 4. adverse impact of knee disease on patients quality of life for at least 3 - 6 months; 5. patient-reported suffering/impairment due to knee disease. Additional indication criteria, contraindication criteria, and risk factors for adverse outcome were also agreed by a large majority within the multi-perspective stakeholder panel. Conclusion The defined indication criteria constitute a prerequisite for appropriate provision of TKA in patients with knee OA in Germany. In eligible patients, shared-decision making should eventually determine if TKA is performed or not. The next important steps are the implementation of the defined indication criteria, and the prospective investigation of predictors of success or failure of TKA in the context of routine care provision in Germany.

Can 3D ultrasound identify trochlea dysplasia in newborns? Evaluation and applicability of a technique

Femoro-patellar dysplasia is considered as a significant risk factor of patellar instability. Different studies suggest that the shape of the trochlea is already developed in early childhood. Therefore early identification of a dysplastic configuration might be relevant information for the treating physician. An easy applicable routine screening of the trochlea is yet not available. The purpose of this study was to establish and evaluate a screening method for femoro-patellar dysplasia using 3D ultrasound. From 2012 to 2013 we prospectively imaged 160 consecutive femoro-patellar joints in 80 newborns from the 36th to 61st gestational week that underwent a routine hip sonography (Graf). All ultrasounds were performed by a pediatric radiologist with only minimal additional time to the routine hip ultrasound. In 30° flexion of the knee, axial, coronal, and sagittal reformats were used to standardize a reconstructed axial plane through the femoral condyle and the mid-patella. The sulcus angle, the lateral-to-medial facet ratio of the trochlea and the shape of the patella (Wiberg Classification) were evaluated. In all examinations reconstruction of the standardized axial plane was achieved, the mean trochlea angle was 149.1° (SD 4.9°), the lateral-to-medial facet ratio of the trochlea ratio was 1.3 (SD 0.22), and a Wiberg type I patella was found in 95% of the newborn. No statistical difference was detected between boys and girls. Using standardized reconstructions of the axial plane allows measurements to be made with lower operator dependency and higher accuracy in a short time. Therefore 3D ultrasound is an easy applicable and powerful tool to identify trochlea dysplasia in newborns and might be used for screening for trochlea dysplasia.