METABOLIC AND ORTHOPEDIC ASPECT OF X-LINKED VITAMIN D-RESISTANT HYPOPHOSPHATEMIC RICKETS

INTRODUCTION: - The X-linked vitamin D-resistant hypophosphatemic rickets (VDXLR) is a metabolic disorder. Medication treatment consists of oral phosphate substitution and supplementation of active vitamin D compounds. Our study aimed to review our patients with VDXLR, focusing on those undergoing surgery, mainly lengthening procedures. The main parameters of interest were growth, height, the axis of the lower limbs, pain, and degenerative arthropathy. METHODS: - Twelve patients with VDXLR were followed at our institution. Eight patients underwent surgical correction, and three of them in combination with bone lengthening. The corrections were executed at the end of growth in the patients. Clinical end points were height, leg axis, and pain. RESULTS: - Single bilateral surgical correction was performed in six patients; one patient had three and ve corrections. Bone lengthening was performed in three patients. At the last follow-up, the height of seven operated patients was within normal range. In addition, the leg axis was normalized in six patients with mild genua vara in two. Bone healing was excellent, and no surgical complications. There was no one radiological evidence of degenerative arthropathy. CONCLUSIONS: - In case of bone deformity, surgery can safely be performed, independent of age or bone maturation. All patients were happy with the outcomes of axial corrective surgery and bone lengthening, and in the majority. Only one corrective intervention was needed.

Current practice of concomitant surgeries in cartilage repair of the femorotibial compartment of the knee: baseline data of 4968 consecutive patients from the German cartilage registry (KnorpelRegister DGOU)

Introduction The treatment of underlying comorbidities is a field of rising interest in cartilage repair surgery. The aim of this study was to analyze the current practice of concomitant surgeries in cartilage repair of the knee especially in the medial or lateral femorotibial compartment. Type, frequency and distribution of additional surgeries for correction of malalignment, knee instability and meniscus deficiency should be evaluated. Methods Baseline data of 4968 patients of the German Cartilage Registry (KnorpelRegister DGOU) were analyzed regarding the distribution of concomitant surgeries in addition to regenerative cartilage treatment. Results Beyond 4968 patients 2445 patients with cartilage defects in the femorotibial compartment of the knee could be identified. Of these patients 1230 (50.3%) received additional surgeries for correction of malalignment, instability and meniscus deficiency. Predominant procedures were leg axis corrections (31.3%), partial meniscectomy (20.9%) and ACL reconstruction (13.4%). The distribution of the concomitant surgeries varied between cartilage defects according to the different defect genesis. Patients with traumatic defects were younger (36y) and received predominantly ACL reconstructions (29.2%) (degenerative: 6.7%), whereas patients with degenerative defects were older (43y) and underwent predominantly leg axis corrections (38.0%; traumatic: 11.0%). Conclusions This study shows the high frequency and distinct distribution of the concomitant surgeries in addition to regenerative cartilage treatment procedures. Understanding of the underlying cause of the cartilage defect and addressing the comorbidities as a whole joint therapy are of utmost importance for a successful regenerative cartilage treatment. These data provide a baseline for further follow up evaluations and long-term outcome analysis. Level of evidence II.

Tissue-specific versus pleiotropic enhancers within the bric-a-brac tandem gene duplicates display differential regulatory activity and evolutionary conservation

During animal evolution, de novo emergence and modifications of pre-existing transcriptional enhancers have contributed to biological innovations, by implementing gene regulatory networks. The Drosophila melanogaster bric-a-brac ( bab ) complex, comprising the tandem paralogous genes bab1 - 2 , provides a paradigm to address how enhancers contribute and co-evolve to regulate jointly or differentially duplicated genes. We previously characterized an intergenic enhancer (named LAE) governing bab2 expression in leg and antennal tissues. We show here that LAE activity also regulates bab1 . CRISPR/Cas9-mediated LAE excision reveals its critical role for bab2 -specific expression along the proximo-distal leg axis, likely through paralog-specific interaction with the bab2 gene promoter. Furthermore, LAE appears involved but not strictly required for bab1 - 2 co-expression in leg tissues. Phenotypic rescue experiments, chromatin features and a gene reporter assay reveal a large “pleiotropic” bab1 enhancer (termed BER) including a series of cis -regulatory elements active in the leg, antennal, wing, haltere and gonadal tissues. Phylogenomics analyses indicate that (i) bab2 originates from bab1 duplication within the Muscomorpha sublineage, (ii) LAE and bab1 promoter sequences have been evolutionarily-fixed early on within the Brachycera lineage, while (iii) BER elements have been conserved more recently among muscomorphans. Lastly, we identified conserved binding sites for transcription factors known or prone to regulate directly the paralogous bab genes in diverse developmental contexts. This work provides new insights on enhancers, particularly about their emergence, maintenance and functional diversification during evolution.

Patient-Specific Instrumentation Combined With A New Tool for Gap Balancing Is Useful in Total Knee Replacement: 3-Year Follow-Up of A Retrospective Study

Objective：The purpose of this study was to prove that knee function is well recovered using gap balancing technique with patient-specific instrumentation（PSI）combined a new balancer device in total knee arthroplasty (TKA) compared with the measured resection technique.Materials and methods：Data of 152 patients received TKA from August 2014 to June 2016 were studied retrospectively. Gap balancing technique assisted by PSI combined a new balance device was used in 80 patients (82 knees) and the measured resection technique was used in the surgery in 70 patients (70 knees). The data of surgery, imaging and knee function were compared. Results：The gap balancing technique assisted by PSI and a new balancer device was feasible in all operated knees and found to be reliable. In total, 152 patients (150 knees) with ages ranging from 52 to 78 years (mean 67 years) underwent TKA during the study period. The follow-up ranged from 35 to 52 months (mean 45 months). Only one patient underwent revision surgery in gap balance group at 2 years postoperatively due to infection. There was no difference in the incidence of anterior knee pain between the two groups. 2 patients received or required revisions. Until the latest follow-up, the mean flexion degree、KSS scores、VAS scores were not significantly different between the measured resection group and gap-balancing group at 12 weeks and 36 weeks. The average joint line displacement in GB group was 1.3 ± 1.1 mm (range 0-3) proximal and 1.2±1.4 mm in MR group. No outliers＞5 mm in each group were recorded. The mean leg axis was 1.8°±1.5°varus (range 0°-3°varus) versus the neutral mechanical axis in GB group and 1.4°±1.2°(range 0°-3°)in MR group. No outliers with＞ 3° deviation in each group were recorded.Conclusions：The gap balancing technique assisted by the new balancer device and PSI can be used to achieve accurate femoral component alignment as well as measured resection in 3 years outcomes. The new balancer device can be taken into account by surgeons who prefer the gap-balancing technique together with the PSI.

A Feasibility Pilot Study on the Use of Telemedicine for the Examination of the Knee Joint

Background In times of a pandemic threat, such as COVID-19, and the need for reduced direct doctor-patient contact, internet-based telemedicine has attracted more and more attention as a surrogate service. Suspending the diagnosis and treatment of non-virus related diseases for longer periods of time is not a viable option since this would only exacerbate problems on the patient and national level. The need for alternative treatment modalities increased rather quickly. So far, telemedical applications have mainly focused on teleradiological diagnosis, follow-up and monitoring of psychiatric and internal diseases, as well as geriatric patient care. As far as these authors are aware, orthopaedic physical examination of the knee joint, including trauma work-up, has not been the subject of any studies to date. This feasibility study explores how video consultation can be designed and implemented in the context of history taking and physical examination in knee joint complaints. Material and Method 21 patient actors (PA) with simulated complaints of the knee joint were examined individually for each diagnosis, first via video consultation and then directly by a specialist (SP). One PA group has a medical background, the other was made up of laypersons. The time was measured for both types of consultation. The physician documented the detected symptoms, the quality of implementation of the self-examination steps, and the derived diagnosis on an assessment form. After completion of both consultation sessions, the PAs were handed a questionnaire on the respective examination modality. Results With the video consultation the examination lasted 8.63 (± 2.5) minutes on average and with the regular consultation in person 5.63 (± 1.7) minutes (p < 0.001). For the group with medical background the examination lasted 7.67 (± 1.4) minutes on average, while for the lay group the video consultation took 9.7 (± 3.1) minutes (p = 0.049). With increased age, the video consultation was prolonged (p = 0.032; r = 0.47). The mean value for self-examination of leg axis, gait pattern and degrees of freedom was 9.32 (± 0.4) of 10 points. The following functional tests resulted in lower mean values (points): Payr 7.2 (± 2.3), Merke 5.9 (± 2.8), no-touch Lachmann 6.4 (± 2.7), gravity sign-recurvatum 6.7 (± 2.4). The mean grade by the PAs for the feasibility of self-examination was 2.43 (± 0.98) out of 5 points. Conclusion The video consultation for musculoskeletal complaints of the knee joint allows exploratory remote examination and helps to minimise the number of patients in hospitals and practices. It takes longer for the physician to perform and does not permit functional testing for ligament injuries of the knee joint. In its present form, telemedical examination is not able to fully replace personal consultation.

Patient-reported outcome after patient-specific unicondylar knee arthroplasty for unicompartmental knee osteoarthritis

Background Unicondylar knee arthroplasty was introduced in the late 1960s and remains a topic of controversial discussion. Patient-specific instruments and patient-specific implants are not yet the standard of care. The question remains whether this time-consuming and costly technique can be beneficial for the patient. The aim of this study was to evaluate whether a custom-made unicondylar knee arthroplasty leads to improved patient-reported outcome. Methods This retrospective study evaluates the patient-reported outcome after custom-made unicondylar knee arthroplasty (CM-UKA, ConforMIS™ iUni® G2, ConforMIS Inc., Billerica, MA, USA). We evaluated 29 patients (31 knees) at an average of 2.4 years (range 1.2–3.6 years) after operation for unicondylar osteoarthritis of the knee. The target zone for the postoperative leg axis was a slight under-correction of 0–2° varus. Follow-up evaluation included the Forgotten Joint Score (FJS), the Knee Society Score (KSS), a Visual Analogue Scale (VAS) and a radiographic evaluation including a long-leg radiograph. Primary outcome measure was patient satisfaction based on the Forgotten Joint Score. Results We found an excellent postoperative health-related quality of life with a mean FJS of 76.8 (SD 17.9) indicating a low level of joint awareness after CM-UKA. The mean preoperative KSS was 66.0 (SD 13.71) and 59.4 (17.9) for the KSS function score. The increase was 22.8 points for the KSS knee score (p < 0.0001) and 34.8 points for the KSS function score (p < 0.0001). The VAS for pain decreased from a mean of 5.4 (SD 1.8) to 1.1 (SD 1.2) (p < 0.0001). The malalignment rate with a postoperative deviation of more than 2° in the leg axis was 29%. There was no evidence of component loosening after a mean follow-up of 2.4 years. Conclusions Custom-made unicondylar knee arthroplasty (CM-UKA) can provide improved clinical and functional outcomes for patients with isolated knee osteoarthritis of the medial compartment. We found excellent results regarding patient satisfaction and a low malalignment rate for CM-UKA. Further studies are needed to investigate long-term survivorship of the implant. Level of evidence Level IV. Trial registration Trial Registration number: Z-2014-0389-10 Regensburg Clinical Studies Center (REGCSC) 09/07/2014.

Better outcomes and reduced failures for arthroplasty over osteotomy for advanced compartmental knee osteoarthritis in patients older than 50 years

Background Both compartmental knee arthroplasty (CKA) and open-wedge high tibial osteotomy (HTO) may be used to treat patients older than 50 years of age with advanced compartmental osteoarthritis (OA) secondary to leg axis deformities. A meta-analysis was conducted to clarify the role of open-wedge HTO versus CKA for patients older than 50 years with advanced compartmental knee OA. The present investigation aimed to analyse the clinical outcomes, implant failure and survivorship. Methods This meta-analysis was performed in accordance with the PRISMA guidelines. In September 2020, the main online databases were accessed. All clinical trials comparing the outcomes of open-wedge HTO versus CKA for compartmental knee OA were considered. Data analysis was performed through the Review Manager Software 5.3 (the Nordic Cochrane Collaboration, Copenhagen). Implant survivorship was analysed with a Kaplan-Meier (KM) curve that was performed using the STATA/MP software (StataCorp, College Station, TX). Results Data from 618 (HTO, 307; CKA, 311) patients were collected. Good baseline comparability among patient age, BMI and gender was detected. The Tegner Activity Scale was higher in the CKA group (P = 0.04), as were the Lysholm score (P = 0.001), the International Knee Documentation Committee (P = 0.0001) and the Knee injury and Osteoarthritis Outcome Score (P = 0.05). At a mean follow-up of 5 years, revisions were less in the CKA cohort (OR, 2.27; P = 0.004). The Kaplan-Meier curve evidenced longer implant survivorship in favour of the CKA group (P = 0.01). Conclusion In patients older than 50 years of age with compartmental knee OA secondary to frontal axis leg deformities, CKA performed better than open-wedge HTO.

Intraarticular osteotomy of malunited tibial plateau fractures: an analysis of clinical results with a mean follow-up after 4 years

Purpose Malunions are a common complication after tibial plateau fractures (TPF), leading to stiffness, pseudo-instability and posttraumatic osteoarthritis. The purpose of this study was to analyse the clinical outcome after intraarticular osteotomy of malunited TPF and to perform a failure analysis. Methods Between 2013 and 2018, 23 patients (11 males, 12 females; 43.8 ± 12.8 years) with intraarticular osteotomy after malunited TPF were included in the retrospective study. Clinical examination and postoperative scores were collected with a minimum follow-up of 24 months. Malunion was measured on pre- and postoperative CT scans and localized according to the 10-segment classification while the leg axis in the frontal plane was measured pre- and postoperatively on long leg standing radiographs. Results Excellent and good clinical outcome was achieved in 73.9% (n = 17) of the cases and patient related outcome improved significantly (Tegner 3.3 ± 1.6–5 ± 1.8, p < 0.001; clinical Rasmussen 14.6 ± 3.8–24.9 ± 4.4, p < 0.001). Radiological parameters also improved as an intraarticular step-off was reduced from 9 ± 3.8 to 0.6 ± 0.8 mm (p < 0.001) and a lower limb malalignment from 7.2 ± 4.8° to 1.5 ± 1.9° (p = 0.003). Failure analysis showed that an impaired clinical result correlated with a postoperative extension (n = 3, p < 0.001) and flexion deficit (n = 4, p = 0.035). Conclusion Intraarticular osteotomy of malunited TPF lead to good clinical results with significant clinical and radiological improvement in most cases while an impaired patient outcome correlated with a limited range of motion. This study is the first failure analysis of intraarticular osteotomy after malunited TPF published up to now.