[The painful knee in children]. / Das schmerzhafte kindliche Kniegelenk.

Knee pain is one of the most common reasons for medical consultation for musculoskeletal problems in the paediatric population. The aetiology is of very variable origin and necessitates a precise assessment. In addition to a thorough anamnesis, clinical and imaging examination methods, as well as laboratory diagnostics are of utmost importance to establish a proper diagnosis and an adequate treatment regimen. This chapter summarises the current diagnostic algorithm for dealing with knee pain in children and adolescents.

Medium-term Results After Femoral Head Resection and Subtrochanteric Valgus Osteotomy in Children and Adolescents With Neuromuscular Disorders.

BACKGROUND: Various salvage surgical procedures for painful hip dislocation in adolescent patients with cerebral palsy exist. To date, no significant differences among these surgical techniques have been described. In our institution the McHale procedure is the standard of care for painful chronically dislocated hips with or without deformity of the femoral head in patients with cerebral palsy. This study focuses on mid-term results after surgical treatment. METHODS: Surgical reports and patient charts were analyzed retrospectively. All x-rays were evaluated and migration of the proximal femur and heterotopic ossification according to Brooker were recorded. In addition, we conducted a telephone interview with the caretakers with special reference to pain preoperatively and postoperatively and after implant removal, sitting tolerance, range of motion, mobility, quality of life, and personal hygiene. RESULTS: Fifty-two patients (65 hips) with a mean age of 13.5 ± 3.6 years (range: 4 to -20 y) were included. Mean surgery time was 178.4 ± 63.4 minutes (range: 45 to 380 min) and mean follow-up was 45.17 ± 30.6 months (range: 12 to 204 mo). A significant difference between preoperative and postoperative pain levels was found, P <0.001. Personal hygiene ( P =0.02) and quality of life ( P =0.013) improved significantly. Eighty-five percent of the caregivers would have the surgery performed on their child again and 81% of the caregivers would recommend the surgery to others. The removal of implants leads to a significant improvement in pain ( P =0.011). A total of 22 complications in 65 McHale procedures (33.9%) were related to the procedures. CONCLUSIONS: A significant reduction in pain and a significant improvement of hygiene as well as quality of life can be achieved with the McHale procedure in painful chronically dislocated hips in patients with cerebral palsy. Overall, the procedure is predominantly experienced as helpful by the caregivers and recommended to others. The removal of the implants improves pain significantly, but complications may occur in one third of the patients. LEVEL OF EVIDENCE: IV.

Radiolucent zones of biodegradable magnesium-based screws in children and adolescents-a radiographic analysis.

INTRODUCTION: Albeit the implantation of magnesium-based biodegradable implants can avoid a second surgery for implant removal, the postoperative occurrence of radiolucent zones around these implants based on corrosion processes has not been previously investigated in children and adolescents. We sought to characterize the distinct temporal and spatial dynamics for magnesium-based implants based on standard clinical routine radiographs. MATERIALS AND METHODS: We retrospectively analyzed 29 patients, treated with magnesium-based compression screws (MAGNEZIX® CS 2.7 mm, CS 3.2 mm, CSC 4.8 mm; Syntellix AG) for fracture fixation, osteotomy, or osteochondral refixation. During a follow-up examination, the clinical and functional status was evaluated. Based on digital radiographs, the ratio of the area of the radiolucent zone and that of the screw was evaluated to assess implant degradation at two follow-up visits (i.e., after 6-8 weeks and 12-24 weeks). RESULTS: In 29 patients (16/29 females, 14.03 ± 2.13 years), a total of 57 implants were evaluated that were used for osteotomy (n = 13, screws n = 26), fracture fixation (n = 9, screws n = 18), or osteochondral refixation (n = 7, screws n = 13). All patients healed without complications and regained full function. Radiolucent zones were observed in 27/29 patients at the first follow-up, with significantly decreased ratios at the second follow-up (2.10 ± 0.55 vs 1.64 ± 0.60, p = 0.0006). Regression analyses were performed to assess the temporal dynamics of radiolucent zones and revealed significant logarithmic developments for the 2.7 mm and 3.2 mm screws, marked by a strong ratio decrease during the first weeks and an almost complete disappearance after approximately 100 days and 200 days, respectively. In contrast, the ceramic-coated 4.8 mm screws presented a significant linear and slower decrease of radiolucent zones. CONCLUSION: Radiolucent zones are a common phenomenon in the course of implant degradation. However, they represent a self-limiting phenomenon. Remarkably, neither implant failure nor affected implant function is noted in this context. Yet, the microstructural changes accompanying the presence of radiolucent zones remain to be analyzed by three-dimensional high-resolution imaging.

Localization and Likelihood of Chondral and Osteochondral Lesions After Patellar Dislocation in Surgically Treated Children and Adolescents.

Background: Patellar dislocation is a common injury in children and adolescents. There is a lack of information about concomitant osteochondral lesions in these patients. Hypothesis: We hypothesized that the likelihood of chondral or osteochondral lesions would increase with each prior patellar dislocation and that the appearance of lesions in surgically treated children and adolescents would be influenced by age, sex, injury mechanism, and body mass index (BMI). Study Design: Case-control study; Level of evidence, 3. Methods: Inclusion criteria were (1) age <18 years, (2) surgical treatment with diagnostic arthroscopy of the knee including description of chondral and osteochondral lesions, and (3) maximum time period between the last patellar dislocation and presentation in our department of 6 weeks and maximum of 4 weeks between presentation and surgery. A total of 153 children (173 knees) with a mean age of 13.0 ± 2.1 years were included. All surgical reports and intraoperative arthroscopic imaging were analyzed retrospectively for the location and severity of lesions. The likelihood of lesions was calculated with multiple stepwise regression models regarding injury mechanism, number of dislocations, sex, age, physeal closure, and BMI. Results: The regression model to predict femoral lesions was statistically significant (χ2[5] = 26.55; P < .001) and identified male sex, BMI ≥25, traumatic injury mechanism, and physeal closure as independent factors associated with the appearance of femoral lesions. The second regression model predicting the appearance of patellar lesions was also statistically significant (χ2[4] = 26.07; P < .001) and identified the traumatic injury mechanism as a single independent predictor for patellar lesions. Conclusion: BMI ≥25, male sex, and physeal closure were factors significantly associated with femoral chondral and osteochondral lesions in our cohort. In case of traumatic lateral patellar dislocation (LPD), the likelihood of patellar and femoral chondral and osteochondral lesions is significantly higher than in nontraumatic LPD. Early magnetic resonance imaging and surgical treatment should be considered in obese patients, male patients, and patients with physeal closure and after traumatic LPD.

Effects of Educational Video on Pre-operative Anxiety in Children - A Randomized Controlled Trial.

Objective: Audio-visual interventions have been used to provide relevant patient information to reduce pre-operative anxiety in children. The aim of the study was to investigate whether self-reported state anxiety in children could be reduced by presenting a child-friendly educational video on the day of surgery. Methods: A prospective, single-blinded, two-armed, randomized controlled study was designed with three measurement time points including 90 children (6-17 years) and their parents. In the intervention group (IG), the children and their parents were shown a child-friendly video explaining the perioperative procedures that would be applied during the hospital stay, in addition to receiving standard information. In the control group (CG), children and parents received standard information provided by the nursing staff. The primary outcome was any change in the children's pre-operative state anxiety levels, as measured by the State-Trait Operation Anxiety Inventory (STOA). A secondary outcome was patient satisfaction regarding the received information. Results: Anxiety was significantly reduced in both groups after receiving either the intervention plus standard information or the standard information only. No significant difference in anxiety reduction was observed between the IG and the CG. However, the children and parents in the IG reported fewer worries than those in the CG. Conclusion: A child-friendly, educational video can be an additional tool for providing patient information and reducing pre-operative anxiety in children and their parents. Further studies should focus on the timing of the intervention and on age- and developmentally appropriate information formats and contents to address children's pre-operative anxiety. Clinical Trial Registration: Patient Anxiety Reduction in Children by Using Simple Explanation Videos, ID: NCT0441377; www.clinicaltrials.gov, Data Sharing Statement: Deidentified individual participant data will not be made available.

Safety and performance of biodegradable magnesium-based implants in children and adolescents.

AIMS: Biodegradable magnesium-based alloy implants represent a promising option in orthopedic surgery, as the clinical outcomes have been reported to be comparable to those of titanium implants and no surgical interventions are required for removal. To date, little is known about the results of the use of these implants in children and adolescents. Therefore, the aim of the present study was to analyze the safety and performance of these implants in children and adolescents. PATIENTS AND METHODS: Eighty-nine patients treated with magnesium-based implants for fracture stabilization, osteotomy and osteochondral refixation were analyzed; 38 were treated by osteosynthesis; 18, osteotomy; and 33, osteochondral refixation. The mean follow-up duration was 8.2 months (range, 1.5-30 months). Clinical and radiographical follow-up examinations were performed at 4-8 weeks and 3-6 months, respectively, to evaluate implant performance and osseous consolidation. RESULTS: Clinical outcomes were rated as good to very good in all patients. Radiolucent zones were apparent after surgery in all patients but were noted to decrease in size during the follow-up period. Revision surgery was necessary in 1 of 89 patients who had a highly unstable osteochondritis dissecans lesion of the knee. None of the magnesium-based implants required surgical removal. CONCLUSION: Magnesium-based implants in children and adolescents results in good clinical outcomes when used for fracture stabilization, osteotomy and osteochondral defect refixation. Future studies are needed to further analyze the significance of the transient appearance and temporal development of radiolucent zones in the growing skeleton as well as the long-term performance of these implants.

Hip pathologies in mucopolysaccharidosis type III.

BACKGROUND: Mucopolysaccharidosis type III (MPS III) comprises a group of rare lysosomal storage diseases. Although musculoskeletal symptoms are less pronounced than in other MPS subtypes, pathologies of hip and spine have been reported in MPS III patients. The purpose of this study was to describe hip pathologies and influencing parameters in MPS III patients. METHODS: A retrospective chart review was performed for 101 MPS III patients. Thirty-two patients met the inclusion criteria of enzymatically or genetically confirmed diagnosis and anteroposterior radiograph of the hips. Modified Ficat classification, Wiberg's center-edge angle, and Reimer's migration percentage were measured. RESULTS: The mean age at data assessment was 11.0 years (SD 5.7). Osteonecrosis of the femoral head was observed in 17/32 patients. No statistically significant association was found between these changes and age, sex, or MPS III subtype. Patients with a severe phenotype showed significantly higher rates of osteonecrosis (14/17) than patients with an intermediate phenotype. Hip dysplasia was present in 9/32 patients and was significantly associated with osteonecrosis of the femoral head (p = 0.04). CONCLUSIONS: The present study demonstrates a high rate of hip pathologies in MPS III patients. Hip dysplasia and severe phenotype were significantly correlated with osteonecrosis of the femoral head. Therefore, radiographs of the hips are highly recommended in baseline and follow-up assessments of MPS III patients. TRIAL REGISTRATION: Retrospectively registered.

Electromagnetic navigation reduces radiation exposure for retrograde drilling in osteochondrosis dissecans of the talus.

BACKGROUND: Retrograde drilling in osteochondrosis dissecans (OCD) is a widely used surgical intervention. A radiation-free electromagnetic navigation system (ENS)-based method was compared with the standard freehand fluoroscopic (SFF) method regarding clinical applicability. METHODS: We performed a clinical cohort study at a department of Orthopaedics in a Level 1 children's hospital with 40 patients (20 SFF and 20 ENS). Retrograde drilling of the talar dome was used in patients with unstable medial OCD (MRI stage 2 according to Hepple's revised classification; stage 2 according to the International Cartilage Repair Society). The outcome measurements were: (a) Intraoperative fluoroscopy exposure and length of surgery and (b) Postoperative serial follow-up MRIs every 6 months. RESULTS: 22 female and 18 male patients aged 13.8 ± 1.6 years (range: 11-17 years) were included. Using the ENS technique, length of surgery was significantly reduced to 20.2 ± 6.4 min compared to 36.1 ± 11.8 min (p < 0.01) for the SFF technique. The average x-ray radiation time for the SFF technique was 23.5 ± 13.5 sec and 1.9 ± 1.7 sec for the ENS technique (p < 0.01). Radiation exposure was significantly reduced from 44.6 ± 19.7 mSv (SFF technique) to 5.6 ± 2.8 mSv (ENS technique) (p < 0.01). Intraoperative perforation of cartilage occurred once in the SFF group. Correct placement of the drilling channel was verified in all patients on follow-up MRI after six months and a timely healing was seen after two years. CONCLUSIONS: The ENS method provides for a significant reduction in length of surgery and radiation exposure. ENS was without intraoperative cartilage perforation. The clinical and radiological follow-up parameters are comparable for SFF- and ENS-guided retrograde drilling. TRIAL REGISTRATION: WF - 085/20, 05/2020 "retrospectively registered" https://www.aerztekammer-hamburg.org/ethik_kommission.html .

Validity of Ultrasound Compared with Magnetic Resonance Imaging in Evaluation of Osteochondritis Dissecans of the Distal Femur in Children.

OBJECTIVE: Magnetic resonance imaging (MRI) is currently the gold standard to diagnose and monitor osteochondritis dissecans (OCD) of the knee. The purpose of this study was to evaluate for the first time if ultrasound imaging can be used to visualize osteochondritis dissecans of the distal femur. DESIGN: From May 2008 to December 2013, 44 children (26 boys and 18 girls) presenting with OCD of the knee in our department were examined and evaluated by ultrasound imaging. Mean age at diagnosis was 11.8 ± 2.2 years. Two independent experienced orthopedic surgeons analyzed the localization, stage, and the size of the OCD via ultrasound and compared the results with the MRI findings. RESULTS: Ultrasonic examination has limitations in assessing the OCD stage I and therefore is not suitable for evaluating this stage of the disease. In stages II to IV, a good correlation to MRI regarding defect localization and size can be found, when the defect is localized in a region that is accessible to ultrasonic examination. CONCLUSION: Ultrasonic scan is an appropriate tool for the screening and monitoring of OCDs stages II to IV. It provides an inexpensive and readily available alternative to MRI. In addition, the healing process of higher grade defects as well as the screening of the opposite side can also be performed by ultrasound. Detection of defects being localized close to the intercondylar notch or far posterior on the lateral condyle are limitations for the use of ultrasound.

Fixation of Unstable Osteochondritis Dissecans Lesions and Displaced Osteochondral Fragments Using New Biodegradable Magnesium Pins in Adolescents.

OBJECTIVE: Fixation of unstable osteochondritis dissecans (OCD) lesions and displaced osteochondral fragments are frequently performed procedures in pediatric orthopedic surgery. Since 2018, CE-certified MAGNEZIX pins are used in our institution in these cases. The aim of this study was (1) to analyze safety, efficiency, and limitations of magnesium-pin-based fixation of unstable OCD lesions and displaced osteochondral fragments and (2) to report clinical and radiological outcomes at short-term follow-up (FU). DESIGN: In this prospective cohort study, 19 patients (10 girls and 9 boys) were included. Inclusion criteria were (1) magnetic resonance imaging-confirmed unstable OCD lesion or displaced osteochondral fragment, (2) fixation with magnesium-based pins, and (3) minimum FU of 6 months. X-rays were taken 6 weeks and 6 months after operation and magnetic resonance imaging scans every 4 to 6 months to assess the healing progress. RESULTS: In total 67 pins were used, with a mean of 3.6 ± 1.4 per patient. Average age at surgery was 13.7 years (11-17 years). Mean time of operation was 56 ± 31 minutes, including arthroscopy, fixation, and patellar realignment (n = 6). No intraoperative complications occurred. Average FU was 11.3 ± 4.2 months (6-20 months). No redislocation or new dislocation occurred. Until now a complete radiographic healing occurred in 12 cases. Due to an implant failure in one case 11 weeks after the index surgery a revision became necessary. CONCLUSIONS: In short-term FU of 11 ± 4 months MAGNEZIX pins provide high stability after fixation of unstable OCDs and displaced osteochondral fragments leading to uncomplicated and timely healing.

The Use of Bovine Xenogeneic Bone Graft for Dega Pelvic Osteotomy in Children with Hip Dysplasia: A Retrospective Study of 147 Treated Hips.

BACKGROUNDS: Dega pelvic osteotomy is commonly used to correct acetabular dysplasia in children with open triradiate cartilage. The use of bovine xenogeneic bone graft (Tutobone®) for Dega osteotomy has not been reported so far. This study aimed to determine the clinical and radiological outcome in a large series of children with hip dysplasia who were treated by Dega osteotomy using a bovine xenogeneic block for stabilisation. METHODS: A retrospective, single-centre study was conducted including 101 patients (147 hips) with different underlying diseases. The acetabular angle of Hilgenreiner (AA) and the lateral center-edge angle (LCA) were analysed to quantify the correction of acetabular indices. Graft incorporation was assessed using the Goldberg scoring system. RESULTS: the mean preoperative AA improved from 28.1 (SD: 6.7) to 14.7 (SD: 5.1) after surgery (p < 0.001). The mean preoperative LCA improved from 9.9 (SD: 6.7) to 21.8 (SD: 6.8) postoperatively (p < 0.001). Both indices remained stable at the one-year follow-up examination. Graft incorporation was excellent with a mean Goldberg score of 6.6. Heterotopic ossification occurred in one hip without clinical relevance. Graft-related complications were not noted. CONCLUSIONS: Dega osteotomy using Tutobone® is safe and effective in the treatment of acetabular dysplasia in children independent of the underlying disease.

Outcome of the modified Dunn procedure in severe chronic or acute on chronic slipped capital femoral epiphysis.

BACKGROUND: In recent years, the modified Dunn osteotomy has gained popularity to treat slipped capital femoral epiphysis (SCFE) with various complication rates. Most studies included patients with different severities. This study aimed to determine (1) the radiological and clinical outcome, (2) the health-related quality of life, and (3) the incidence of avascular necrosis of the femoral head (AVN) in patients with severe chronic or acute on chronic SCFE treated by the modified Dunn procedure. METHODS: Out of 150 patients with SCFE treated at our institution between 2001 and 2014, 15 patients (mean age 12.9 years (range 11.8-15)) were treated by the modified Dunn procedure. Eight SCFE were chronic and 7 acute on chronic. All slips were severe with a mean Southwick slip angle (SSA) of 67° (range 60-80). Radiographic and clinical outcomes were measured. Mean time of follow-up was 3.8 years (range 1-10). RESULTS: Anatomical reduction was achieved in all cases. Good radiological results according to the Stulberg Classification (grade 1 + 2) and the Sphericity Deviation Score (< 30) were found in 9 out of 13 patients at the last follow-up. Clinical and functional outcome analysis revealed good results in 8 out of 10 patients (Harris Hip Score > 80). The quality of life measured by the Nottingham Health Profile (NHP) was described good in 10 out of 10 patients. Four out of 15 patients developed an AVN. CONCLUSIONS: The modified Dunn procedure has a great potential to restore proximal femur geometry in severe chronic or acute on chronic SCFE. It should be considered only if there is no other possibility to restore proximal femur geometry, as is the case in severe slips, due to the risk of AVN.

Strategies for Treating Scoliosis in Early Childhood.

BACKGROUND: Scoliosis in early childhood is defined as abnormal curvature of the spine of any etiology that arises before age 10. The affected children are at high risk of developing restrictive pulmonary dysfunction. The treatment presents major challenges because of the complexity and high morbidity of the disease. METHODS: This article is based on pertinent articles retrieved by a selective literature search, and on the results of a retrospective study by the authors. RESULTS: In addition to conservative treatment methods including physiotherapy, casts, and corsets, progressive scoliosis usually requires early surgical intervention. In recent years, many different so-called non-fusion techniques have been developed for the surgical treatment of early childhood scoliosis. The goal of this new strategy is to avoid early fusion procedures and to enable further growth of the rib cage, lungs, and spine in addition to correcting the scoliosis. The authors also present their own intermediate-term results with a novel growth-preserving spinal operation that exploits magnet technology. CONCLUSION: Because of the low prevalence and heterogeneous etiology of early childhood scoliosis, the literature to date contains no randomized controlled therapeutic trials concerning this small group of high-risk patients. For the treatment to succeed, it is essential for specialists from all of the involved medical disciplines to work closely together. Conservative measures such as physiotherapy, casts, and corsets can delay the (frequent) need for surgery or even make surgery unneces - sary, particularly in the idiopathic types of early childhood scoliosis. The new non-fusion techniques enable continued growth of the spine, rib cage, and lung in addition to correcting the scoliosis.

Anterior distal femoral hemiepiphysiodesis can reduce fixed flexion deformity of the knee: a retrospective study of 83 knees.

Background and purpose - Fixed knee flexion deformity in children is a common problem in various diseases including myelomeningocele and cerebral palsy. Until now, only a few studies focusing on the surgical procedure of anterior distal femoral hemiepiphysiodesis have been published. We analyzed outcome and correction rate in the largest case series to date of patients treated by staples or 8-plates. Patients and methods - We reviewed the medical records of all patients with fixed knee flexion deformity who were treated with anterior distal femoral hemiepiphysiodesis using either staples or 8-plates between the years 2002 and 2017 (73 patients; 130 knees). 49 patients (83 knees) had completed treatment with implant removal at the time of full correction of the deformity or at skeletal maturity and were included. The average age at operation was 12 years (6-20). Patients were assigned to 3 different groups based on their diagnosis: cerebral palsy, myelomeningocele, and the "other" group.d Results - Mean fixed knee flexion deformity improved from 21° (10-60°) to 8° (0-50°) (p < 0.001) with an average correction rate of 0.44° per month (range -2.14° to 1.74°). The correction rate per month was lowest for patients with cerebral palsy (0.20°), followed by the myelomeningocele group (0.50°), and the "other" group (0.58°). Implant loosening occurred in 10% of the treated knees with consecutive re-implantation in 5% of the cases. Interpretation - Anterior distal femoral hemiepiphysiodesis is an effective and safe method for the treatment of fixed knee flexion deformity in children. The optimal timing depends on the remaining individual growth potential, the underlying disease, and the extent of the deformity.

Resection of Medial Talocalcaneal Coalition With Interposition of a Pediculated Flap of Tibialis Posterior Tendon Sheath.

BACKGROUND: The purpose of the study was to present a novel operative technique in the management of medial talocalcaneal coalition (TC) and to report our clinical and radiologic results after interposition of a pediculated flap (PF) of the tibialis posterior tendon sheath. METHODS: Twelve feet of 10 patients with a medial TC were treated with the interposition of PF of the tibialis posterior tendon sheath following resection. Pre- and postoperative clinical examinations were performed to evaluate the range of motion and the function of the tibialis posterior muscle of the affected foot. Pain was registered by visual analog scale (VAS) and the function of the foot by the American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score. The mean follow-up duration was 57.2 months (SD ±37.2 range 12-128) after surgery. Magnetic resonance imaging (MRI) was carried out to assess the outcome. RESULTS: All patients reported a significant reduction of pain ( P = .002) at the final follow-up. The activity level had improved since the operation, and the subtalar joint motion was increased, but no weakness of the tibialis posterior muscle could be observed. The AOFAS hindfoot score was significantly improved ( P = .002). MRI did not reveal any migration of the tibialis posterior tendon sheath, and the interposed PF was confirmed at the resection zone. Furthermore, no TC relapse or ruptures of the functional anatomical structures could be observed. CONCLUSION: The resection combined with the interposition of a PF of the tendon sheath seems to avoid relapse of TC and improves symptoms and the function of the foot. LEVEL OF EVIDENCE: Level IV, case series.

Hip Morphology in MPS-1H Patients: An MRI-based Study.

BACKGROUND: Hip dysplasia is common in mucopolysaccharidosis type-1H (MPS-1H) patients, but its morphology is not completely understood. No magnetic resonance imaging (MRI)-based studies have been reported in the literature. The purpose of this study was to improve knowledge of hip dysplasia pathology by describing the hip morphology of these patients in MRI scans, plain radiographs, and arthrograms. METHODS: We performed a retrospective chart review of 18 MPS-1H patients. Supine anteroposterior pelvic radiographs of 36 hips and MRI scans of 18 hips were analyzed. Six arthrographs were also available. RESULTS: Plain radiographs were available for 18 patients. The mean age was 6.0 (SD=3.8) years. The mean acetabular index (AI) was 36.2 degrees (SD=5.8), and the mean migration percentage was 59.0% (SD=17.2). MRI data were available for 9 patients. The MRI findings were compared with the radiographs of the same patient. The mean AI (39.3 degrees, SD=5.8) was confirmed by the MRI findings (39.1 degrees, SD=5.5). The migration percentage was lower in the MRI scans than in the radiographs. Radiologically, the center-edge angle was negative in all patients, with a mean of -16.8 degrees (SD=7.9), and the MRI images produced a more negative value (-19.6 degrees, SD=7.6). The soft tissue coverage of the femoral head was described with the inclusion of the cartilaginous roof and labrum. The cartilaginous AI was 22.4 degrees (SD=7.5), and the labral AI was 13.5 degrees (SD=6.7). All 6 arthrograms revealed stability during dynamic testing. CONCLUSIONS: This study provides the first description of hip morphology in MPS-1H patients through MRI-based data. The cartilaginous coverage of the hip was increased compared with that of healthy children. The use of radiography alone may lead to a misunderstanding of hip morphology. MRI and arthrogram is highly recommended if surgery is considered.

Hip Dysplasia in Mucopolysaccharidosis Type IVA (Morquio A Syndrome) Treated by Proximal Femoral Valgization Osteotomy: A Case Report.

INTRODUCTION: Morquio A syndrome or mucopolysaccharidosis type IVA (MPS IVA) is a progressive lysosomal storage disorder caused by an N-acetylgalactosamine-6-sulfatase deficiency. The abnormal metabolism of glycosaminoglycans among other medical problems leads to various skeletal disorders caused by a dysfunction of endochondral ossification of epiphyseal cartilage. Severe hip dysplasia is common and can lead to pain and impaired mobility. CASE REPORT: We report on a 15-year-old girl suffering from MPS IVA. At the age of 5 years, hip pain and a reduced walking distance were described for the 1sttime. At the age of 9 years, acetabulofemoral dysplasia associated with genuavalga was diagnosed. After pre-operative assessment of the hips including plain radiographs, magnetic resonance imaging, and arthrography with dynamic testing a valgization osteotomy of the proximal femur in combination with a shelf acetabuloplasty was performed. The patient was followed for 6 years with a stable hip joint and without any sign of redislocation. CONCLUSION: Some treatment strategies of hip dysplasia in patients with MPS IVA are described in the literature. The techniques used for congenital hip dysplasia, varisation of the femur in combination with Pemberton, Salter, or shelf acetabuloplasty, are widely reported. Nevertheless, resubluxations were described in some cases. The well-known surgical procedure with valgization of the proximal femur is not reported in literature for MPS IVA patients. In our opinion, dynamic testing with arthrography should strongly be considered for this particular problem before surgical intervention. Pathology-related decisions should be made under consideration of the different surgical techniques.

ß-TCP bone substitutes in tibial plateau depression fractures.

BACKGROUND: The use of beta-tricalciumphospate (ß-TCP, Cerasorb®) ceramics as an alternative for autologous bone-grafting has been outlined previously, however with no study focusing on both clinical and histological outcomes of ß-TCP application in patients with multi-fragment tibial plateau fractures. The aim of this study was to analyze the long-term results of ß-TCP in patients with tibial plateau fractures. METHODS: 52 patients were included in this study. All patients underwent open surgery with ß-TCP block or granulate application. After a mean follow-up of 36months (14-64months), the patients were reviewed. Radiography and computed-tomography were performed, while the Rasmussen score was obtained for clinical outcome. Furthermore, seven patients underwent biopsy during hardware removal, which was subsequently analyzed by histology and backscattered electron microscopy (BSEM). RESULTS: An excellent reduction with two millimeters or less of residual incongruity was achieved in 83% of the patients. At follow-up, no further changes occurred and no nonunions were observed. Functional outcome was good to excellent in 82%. Four patients underwent revision surgery due to reasons unrelated to the bone substitute material. Histologic analyses indicated that new bone was built around the ß-TCP-grafts, however a complete resorption of ß-TCP was not observed. DISCUSSION: ß-TCP combined with internal fixation represents an effective and safe treatment of tibial plateau depression fractures with good functional recovery. While its osteoconductivity seems to be successful, the biological degradation and replacement of ß-TCP is less pronounced in humans than previous animal studies have indicated.