Combined technique for the correction of lower-limb deformities resulting from metabolic bone disease

Multi-segment osteotomy with interlocking intramedullary nail fixation in the treatment of lower limb deformity in older children with hypophosphatemic rickets

Objective

Malformations of the lower limbs caused by hypophosphatemic rickets in older children are mostly complex, occurring on multiple planes without a single apex and showing arcuate bending of the diaphysis combined with torsion deformity, and are difficult to correct. This study retrospectively investigated the effect of and indicators for multi-segment osteotomy with interlocking intramedullary nail fixation in the treatment of bony deformity caused by hypophosphatemic rickets.

Methods

The clinical data of 21 hypophosphatemic rickets patients seen between August 2007 and March 2022 were collected. The age range of the patients at the first surgery was 11 years and 1 month old to 15 years and 3 months old, with an average age of 12 years and 8 months. There were 6 males and 15 females. All patients had abnormal alignment of their lower limbs, with 32 limbs having varus deformity and 10 limbs having valgus deformity.

Results

A total of 67 surgeries were performed across the 21 patients, including 24 cases of femoral osteotomy with antegrade intramedullary nail fixation, 6 cases of femoral osteotomy with retrograde intramedullary nail fixation, and 20 cases of tibial osteotomy with interlocking intramedullary nail fixation. A total of 34 limbs eventually underwent interlocking intramedullary nail fixation, 9 with genu valgum and 25 with genu varus. All 21 patients were followed up for a period of 14∼96 months, with an average of 42.6 months. The ends of the osteotomies achieved bony union in 4-9 months (average 6.8 months), after which normal weight-bearing walking could be resumed. No infection, vascular or neurological complications, or nonunion occurred. During postoperative follow-up, the alignment the lower limbs passed through zone 1 in 13 limbs, zone 2 in 12 limbs, and zone 3 in 5 limbs. The overall rate of an excellent effect was 83.3%.

Conclusion

For lower limb deformity caused by hypophosphatemic rickets in older children, multi-segment osteotomy and strong fixation with interlocking intramedullary nails can achieve good correction outcomes.

Changes of the lower limb deformity in children with FGF23-related hypophosphatemic rickets treated with Burosumab: a single-center prospective study

Fibroblast growth factor 23 (FGF23)-related hypophosphatemic rickets (HPR) are characterized by excess circulating FGF23 and low concentrations of serum phosphorus, leading to skeletal manifestations of rickets, including lower limb deformities in children. The objective of this study was to prospectively evaluate whether treatment with burosumab, a monoclonal antibody neutralizing FGF23, changes lower limb deformities in HPR. Patients who were 15 years of age or younger with a documented clinical diagnosis of HPR, receiving burosumab treatment, and had a minimum follow-up period of one year were included in the study. Various radiological parameters were measured from anteroposterior and lateral radiographs of the bilateral lower limbs taken before administration of burosumab and at 3, 6, 9, and 12 months after treatment for evaluation of lower limb alignment. Outcome was classified as 'improvement', 'no change', or 'deterioration' after 12 months treatment. Five patients (10 limbs), with a mean age of 7.2 years were included in this study. The outcome was 'improvement' in six limbs and 'no change' in four limbs. There were no limbs of 'deterioration'. The improvement in deformities after treatment was more significant in younger patients who originally showed severe lower limb deformities. Older patients with milder deformities, on the other hand, showed less improvement. Burosumab therapy favorably changed lower-limb malalignment in children with FGF23-related HPR.

Acute Correction of Multiplanar Proximal Tibial Deformity Utilizing Fixator-Assisted Intramedullary Nailing

Proximal tibial deformities, particularly varus deformities, are relatively common in adolescents and young adults. The etiology of these deformities is often untreated or undercorrected infantile and adolescent Blount disease. Other less common etiologies include metabolic bone disease-associated deformities, posttraumatic and iatrogenic growth disturbance, and deformity related to surgical treatment or radiation for tumors^1-3. We apply the principles of fixator-assisted acute deformity correction, mostly described for use at the distal aspect of the femur, as well as the principles of anatomic reduction and fixation of proximal-third tibial fractures⁴ to acutely correct these complex deformities in skeletally mature individuals^5-12. We perform acute correction of multiplanar proximal tibial deformity with use of fixator-assisted intramedullary nailing in order to avoid the complications and patient discomfort associated with gradual deformity correction with use of a circular external fixator. This procedure is novel in the treatment of adolescent Blount disease deformity in skeletally mature individuals and can additionally be utilized for other proximal tibial metaphyseal deformities, allowing the accurate and acute correction of all planes of deformity as well as the anatomic and mechanical axes, while avoiding the prolonged use of external fixators.

Description

The patient is positioned supine on a radiolucent table. The locations of the proximal tibial osteotomy, fibular osteotomy, external fixator pin sites, and intramedullary nail insertion site are marked with use of a surgical marker and fluoroscopic imaging. Large external fixator half-pins are placed proximal and distal to the planned tibial osteotomy in both the anterior-posterior and sagittal planes, avoiding the path of the planned tibial intramedullary nail. A fibular osteotomy and then a low-energy tibial osteotomy are performed with use of multiple drill holes and an osteotome. Next, the bone deformity is fully corrected and held in the corrected alignment with the external fixators. Then, the opening drill for the intramedullary nail is introduced into the proximal aspect of the tibia over a guidewire, and blocking screws are placed in the coronal and sagittal planes of the proximal fragment next to the opening reamer. The intramedullary canal is then reamed over a ball-tipped guidewire to the desired diameter and the selected intramedullary nail is placed and secured with proximal and distal interlocking screws. Finally, the external fixators are removed.

Alternatives

Alternative operative treatments include external fixation and gradual or acute deformity correction as well as fixator-assisted acute deformity correction and plate fixation^13-16.

Rationale

Typically, a tibial osteotomy with gradual deformity correction with use of a circular fixator is employed for the treatment of these deformities^3,17. The literature shows this to be an effective technique for accurate correction of these complex proximal tibial deformities. With the advent of internal motorized lengthening nails, however, there have been increasing efforts to develop safe and accurate techniques for acutely correcting bone deformity so that these nails can be utilized to treat both angular deformities and bone-length differences simultaneously. Deformity at the proximal aspect of the tibia is often multiplanar, and complete correction of these deformities requires translation, angulation, and rotation through the osteotomy. An osteotomy performed at the proximal aspect of the tibia results in the equivalent of a proximal-third tibial fracture, which is more challenging and more demanding to fix than a diaphyseal tibial fracture because of the wide medullary canal and the strong deforming muscular forces at the proximal tibia. Fixator-assisted intramedullary nailing with blocking screws allows for the accurate correction of the mechanical and anatomic axes while avoiding external fixation.

Expected Outcomes

The expected outcome is complete bone deformity correction and healing of the osteotomy site(s)².

Important Tips

Careful preoperative planning is essential to accurately correct the anatomic and mechanical axes in all planes.In cases of acute correction of severe bone deformities, consider prophylactic nerve decompression.When possible, avoid the use of a tourniquet in order to minimize tissue trauma, postoperative swelling, and the need for prophylactic fasciotomies.Obtain and hold perfect osseous alignment with use of temporary uniplanar external fixators prior to placing any definitive hardware.

Acronyms and Abbreviations

AP = anteroposteriorIM = intramedullaryPACS = picture archiving and communication systemK-wire = Kirschner wireCORA = center of rotation and angulationDVT = deep venous thrombosisPE = pulmonary embolism.

Complications of orthopedic treatment in patients diagnosed with X-linked hypophosphatemic rickets

OBJECTIVES

XLHR in children with a Rickets Severity Score ≥2 can now be treated with the new antibody drug, Burosumab, which prevents bone deformities and increases gait endurance. This study illustrates the extent of complications in the traditional orthopedic treatment of XLHR. The impact of surgery and severity of complications in this patient population has not been systematically assessed before.

METHODS

The search strategy resulted in 215 studies and data were collected from 19 eligible studies and complications were categorized. Four medical charts of patients with XLHR at Aalborg University Hospital were assessed.

RESULTS

One complication occurred on average per surgical procedure for XLHR in the published literature. The 168 reported complications were categorized as follows: Type I (n=79): Complications with minimal intervention required and treatment goal still achieved, Type II (n=41): Complications with substantial change in treatment plan and treatment goal still achieved, Type IIIA (n=23): Complications with failure to achieve treatment goal and no new pathology or permanent sequelae, Type IIIB (n=25): Complications with failure to achieve treatment goal and/or new pathology or permanent sequelae.

CONCLUSIONS

In average, one complication occurred per surgery and the severity of complications were substantial. The treatment goal was not achieved in 28% of surgeries whereof half of them resulted in permanent sequalae or new pathology. Our findings support the use of Burosumab for treatment of the skeletal changes in XLHR as the reported side-effects in Burosumab treatment appear negligible compared to the impact of surgeries and related complications (Imel EA, Glorieux FH, Whyte MP, Munns CF, Ward LM, Nilsson O, et al. Burosumab versus conventional therapy in children with X-linked hypophosphataemia: a randomised, active-controlled, open-label, phase 3 trial. Lancet 2019;393:2416-27). However, orthopedic surgery might still be needed for correcting deformities restricting activities of daily living in XLHR patients.

Identification of a Novel Missense Mutation of the PHEX Gene in a Large Chinese Family with X-Linked Hypophosphataemia

X-linked hypophosphataemia (XLH) is an X-linked dominant rare disease that refers to the most common hereditary hypophosphatemia (HH) caused by mutations in the phosphate-regulating endopeptidase homolog X-linked gene (PHEX; OMIM: * 300550). However, mutations that have already been reported cannot account for all cases of XLH. Extensive genetic analysis can thus be helpful for arriving at the diagnosis of XLH. Herein, we identified a novel heterozygous mutation of PHEX (NM_000444.5: c.1768G > A) in a large Chinese family with XLH by whole-exome sequencing (WES). In addition, the negative effect of this mutation in PHEX was confirmed by both bioinformatics analysis and in vitro experimentation. The three-dimensional protein-model analysis predicted that this mutation might impair normal zinc binding. Immunofluorescence staining, qPCR, and western blotting analysis confirmed that the mutation we detected attenuated PHEX protein expression. The heterozygous mutation of PHEX (NM_000444.5: c.1768G > A) identified in this study by genetic and functional experiments constitutes a novel genetic cause of XLH, but further study will be required to expand its use in clinical and molecular diagnoses of XLH.

Biopsychosoziales Betreuungskonzept für Kinder mit X‑chromosomaler Hypophosphatämie (XLH)

Patienten mit einer schweren, seltenen und komplexen Erkrankung benötigen das multiprofessionelle biopsychosoziale Betreuungskonzept eines Sozialpädiatrischen Zentrums für chronisch kranke Kinder und Jugendliche. Am Beispiel der Multiorganerkrankung X‑chromosomale Hypophosphatämie (XLH), der häufigsten angeborenen Rachitisform, wird das Betreuungskonzept dargestellt.

Der Erkrankung liegen inaktivierende Mutationen im „Phosphate-regulating gene with Homologies to Endopeptidases on the X‑chromosome“(PHEX)-Gen zugrunde, die zu einer vermehrten Synthese und Sekretion des Fibroblastenwachstumsfaktors 23 (FGF23) führen. FGF23 hat eine wichtige Funktion in der Phosphathomöostase. Durch die hohen FGF23-Konzentrationen kommt es über den renalen Phosphatverlust zur schweren Hypophosphatämie mit der Folge erheblicher Mineralisationsstörungen des Skelettsystems und der Zähne. Stand bis vor Kurzem nur eine konventionelle medikamentöse Therapie aus Phosphat und aktivem Vitamin D zur Verfügung, so ist nun mit dem neutralisierenden FGF23-Antikörper eine gezielte Therapie der Erkrankung möglich. Das multiprofessionelle Betreuungskonzept umfasst zahlreiche ärztliche Spezialisten und ein psychosoziales Team. Ziel der Betreuung ist es, den Patienten mit ihrer schweren chronischen Erkrankung eine altersentsprechende Partizipation ohne größere Teilhabestörung zu ermöglichen. Die Fortsetzung der Betreuung im Erwachsenenalter muss durch eine implementierte Transition sichergestellt werden.

Clinical practice recommendations for the diagnosis and management of X-linked hypophosphataemia

X-linked hypophosphataemia (XLH) is the most common cause of inherited phosphate wasting and is associated with severe complications such as rickets, lower limb deformities, pain, poor mineralization of the teeth and disproportionate short stature in children as well as hyperparathyroidism, osteomalacia, enthesopathies, osteoarthritis and pseudofractures in adults. The characteristics and severity of XLH vary between patients. Because of its rarity, the diagnosis and specific treatment of XLH are frequently delayed, which has a detrimental effect on patient outcomes. In this Evidence-Based Guideline, we recommend that the diagnosis of XLH is based on signs of rickets and/or osteomalacia in association with hypophosphataemia and renal phosphate wasting in the absence of vitamin D or calcium deficiency. Whenever possible, the diagnosis should be confirmed by molecular genetic analysis or measurement of levels of fibroblast growth factor 23 (FGF23) before treatment. Owing to the multisystemic nature of the disease, patients should be seen regularly by multidisciplinary teams organized by a metabolic bone disease expert. In this article, we summarize the current evidence and provide recommendations on features of the disease, including new treatment modalities, to improve knowledge and provide guidance for diagnosis and multidisciplinary care.

In this Evidence-Based Guideline on X-linked hypophosphataemia, the authors identify the criteria for diagnosis of this disease, provide guidance for medical and surgical treatment and explain the challenges of follow-up.

New Developments in the Treatment of X-Linked Hypophosphataemia: Implications for Clinical Management

X-linked hypophosphataemia (XLH) is due to mutations in phosphate-regulating gene with homologies to endopeptidases on the X chromosome (PHEX) and represents the most common heritable form of rickets. In this condition, the hormone fibroblast growth factor 23 (FGF23) is produced in excessive amounts for still unknown reasons, and causes renal phosphate wasting and suppression of 1,25-dihydroxyvitamin D, leading to low serum phosphate concentrations. Prolonged hypophosphataemia decreases apoptosis of hypertrophic chondrocytes in growth plates (causing rickets) and decreases mineralisation of existing bone (causing osteomalacia). In contrast to historical conventional treatment with oral phosphate supplements and active vitamin D for the last 50 years, the new anti-FGF23 antibody treatment (burosumab) targets the primary pathology by blocking FGF23, thereby restoring phosphate homeostasis. In this review, we describe the changes in treatment monitoring, treatment targets and long-term treatment goals, including future opportunities and challenges in the treatment of XLH in children.

Detecting reasons for recurrent deformity in treatment of patients with vitamin D-resistant rickets using diagnostic imaging

PURPOSE

To assess age related manifestations of the femur and tibia in patients with vitamin D-resistant rickets (VDR) and explore causes for recurrent deformity using imaging modalities.

METHODS

Computed tomography (CT), magnetic resonance imaging (MRI) and dual energy X-ray densitometry (DEXA) were used to assess conditions of long bones of lower limbs in patients with vitamin D-resistant rickets aged from 4 years to 30 years preoperatively and after limb lengthening.

RESULTS

Age related MRI findings showed specific structure of the femur and tibia in patients with VDR preoperatively and after operative treatment. Abundant irregular osteoid formed in femoral and tibial physes was shown to reveal complicated nature of bone deformity causing recurrence in patients with VDR at childhood. CT findings allowed us to detect early cortical injury, measure its length with forming Looser's zones, examine significant differences in density measurements of Looser's zones preoperatively and after deformity correction using transosseous osteosynthesis.

CONCLUSION

Recurrent deformity can develop in patients with VDR due to progression of the disease, irregular osteoid deposited in the medial and lateral metaepiphysis, osteoid area measuring over 50% of epiphyseal cross section, insufficient regenerate mineralization, and formation of Looser's zones.

X-linked hypophosphatemic rickets: an Italian experts' opinion survey

Background

X-linked hypophosphatemic rickets (XLH) is the first cause of inherited hypophosphatemia and is caused by mutation in the PHEX gene, resulting in excessive expression of the phosphaturic factor FGF23. Symptoms are mainly related to rickets in children and osteomalacia in adults and cause several complications that can be highly invalidating. Due to its rarity, XLH is poorly known and diagnosis is frequently delayed. Conventional treatment is based on oral phosphate salts supplementation and activated vitamin D analogs, which however, cannot cure the disease in most cases.

Objective

Due to the low prevalence of XLH, an experts’ opinion survey was conducted across Italian centers to collect data on XLH and on its management.

Methods

A questionnaire was developed by a group of experts to collect data on XLH epidemiology, diagnosis and treatment in Italy.

Results

Data from 10 Italian centers (nine of which pediatric) on 175 patients, followed between 1998 and 2017, were included in the survey. Most patients were followed since childhood and 63 children became adults during the investigated period. The diagnosis was made before the age of 1 and between 1 and 5 years in 11 and 50% of cases, respectively. Clinically apparent bone deformities were present in 95% of patients. These were ranked moderate/severe in 75% of subjects and caused growth stunting in 67% of patients. Other frequent complications included bone pain (40%), dental abscesses (33%), and dental malpositions (53%). Treatment protocols varied substantially among centers. Nephrocalcinosis was observed in 34% of patients. Tertiary hyperparathyroidism developed in 6% of patients.

Conclusions

XLH remains a severe condition with significant morbidities.

Joint replacement in X-linked hypophosphatemia

X-linked hypophosphatemia (XLH) is associated with a pervasive, severe degenerative osteoarthritis. We conducted a retrospective chart review/patient survey using the Knee or Hip Osteoarthritis Outcome Score Physical Function Short Form. Fourteen total knee arthroplasties and 7 total hip arthroplasties among 11 patients were included. The mean KOOS-PS score was 31.4 ± 9.7 with a mean follow up of 6.9 years. Mean HOOS-PS score was 14.8 ± 12.9 at a mean follow up of 7.6 years. One knee failed due to aseptic loosening and one hip was revised due to polyethylene wear. In conclusion, total joint arthroplasty is beneficial in XLH.

Total Knee Arthroplasty after Correction of Tibial Diaphyseal Nonunion with Clamshell Osteotomy

Total knee arthroplasty is mostly done to relieve pain and disability from a severe and degenerated knee. Deformities in the coronal and sagittal plane could be corrected with the help of cuts made in tibia and femur during total knee replacement as well as with ligament release. However, large deformities in the lower extremity particularly in the diaphysis region need correction prior to the total knee replacement. It helps to limit the amount of bone that will be cut and helps the ligament release. Several extra articular and intra-articular methods for the correction of diaphyseal deformity have been described. We present the case of clamshell osteotomy for the correction of diaphyseal deformity in the tibia and a total knee replacement after the osteotomy site healed.

Double femoral osteotomy fixed with a Puddu plate and a retrograde intramedullary nail to treat biapical deformity of the femur

Biapical femoral deformities are challenging to treat. In order to correct concomitant metaphyseal and diaphyseal deformities of the femur, the authors propose a double femoral controlled osteotomy with combined internal fixation, consisting of a Puddu plate and an intramedullary nail. The method was described in two patients. Results were analyzed using a visual analog scale (VAS), the Lysholm score, and SF-36. No complications were found. Complete consolidation of the osteotomies and radiographic alignment correction were achieved. Results were obtained with a minimum follow-up of 66 months. Both patients had improved for pain (VAS from 60 to 40 and from 50 to 20 at reassessment), function (Lysholm score from 78 to 93 and from 55 to 73) and quality of life (SF-36, both mental - from 40.7 to 57.1 in case one and from 24.7 to 59.7 in case two - and physical - from 27.7 to 45.6 and from 28.2 to 46.8). The authors have found that this technique is a reliable, accurate, and reproducible solution for biapical deformities of the femur.

Two-year recombinant human growth hormone (rhGH) treatment is more effective in pre-pubertal compared to pubertal short children with X-linked hypophosphatemic rickets (XLHR)

CONTEXT

Twenty-five to 40% of patients with well-controlled X-linked hypophosphatemic rickets (XLHR) have a final height under -2 SDS. Previous studies have shown that recombinant human growth hormone (rhGH) treatment improves linear growth in short children with XLHR.

OBJECTIVE

We studied the effectiveness of rhGH treatment in children with XLHR in a larger cohort.

DESIGN

Monocentric, prospective, non-randomized trial.

SETTING

University hospital in France.

PATIENTS

19 patients with XLHR and a mutation in the PHEX gene. Six male and 6 female Tanner stage 1 patients (age 6.1±2.4years) and 4 male and 3 female Tanner stage 2 patients (age 13.1±1years). At inclusion, height SDS was -2.35±0.8 SDS and growth velocity was -1.12±1.2 SDS.

INTERVENTION

2years of treatment with 67mcg/kg/day of rhGH at initiation. Every three months rhGH dosage was adjusted using an IGF-1 dosing protocol.

MAIN OUTCOME MEASURES

Comparison in change from baseline to year 2 in height and growth velocity.

RESULTS

Height SDS improved from -2.35±0.8 SDS at baseline, to -1.62±0.8 SDS (p=0.01) after one and to -1.2±1 SDS (p=0.04) after two years of rhGH treatment. There was a strong correlation (r²=0.6104, p<0.0001) between the age of onset of rhGH treatment and the number of cm gained over the study period. Pre-pubertal patients height SDS improved compared to baseline height SDS after one (-1.5±0.7, p<0.03) and two (-0.96±1, p<0.03) years of rhGH treatment. In pubertal patients there was no significant improvement in height SDS after one year (-1.75±1) and after two years (-1.7±0.8) of rhGH treatment.

CONCLUSION

Two-year rhGH treatment is effective to treat short stature in XLHR children. Pre-pubertal children responded better to rhGH.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02720770.

Surgical Treatment of an Infected Nonunion of the Middle Third of the Femur Associated with Femoral Shortening in a Hemophilia Patient

The management of nonunion and limb length discrepancy has remained a constant challenge in hemophilic patients. In this study, we aimed to present the treatment of femur infected nonunion and limb length discrepancy in a twenty-seven-year-old patient with hemophilia type A. A 27-year-old male patient with hemophilia type A referred to our institution for the treatment of right femur infected nonunion and 10 cm shortness of the femur. Resection of the nonunion site and bone-to-bone fixation with autologous bone grafting were performed. Compression to the pseudoarthrosis site and distraction from new osteotomy site were applied with the unilateral external fixator. Union was achieved, and 6 cm lengthening was obtained according to the initial length. Patient was followed up for 7 years. After this treatment, the patient is able to walk with full weight bearing on the affected extremity with 4 cm shortening which is compensated by the heel lift. The results of this case indicate that limb lengthening and treatment of nonunion with the external fixation could be reliable and effective method for hemophilic patients.

Description and evaluation of operative deformity correction in calcium-deficiency rickets in Kaduna, northern Nigeria

PURPOSE

Rickets is a recurrent disease worldwide, especially in countries with limited resources (Nield et al Am Fam Physician 74(4):619-626, 2006; Thacher et al Ann Trop Paediatr 26(1):1-16, 2006). Medical therapy including orally administered calcium substitution is shown to improve a patients clinical symptoms and positively impact bone deformities, especially in the lower extremity. Even though orthopaedic intervention is necessary in a significant percentage of patients, few reports exist about operative deformity correction in patients wtih rickets.

METHODS

We describe our concept of operative treatment by single-stage, three-dimensional closing-wedge osteotomies on 45 deformed legs in 27 patients from the rural area of Kaduna, North Nigeria, with calcium-deficiency rickets and evaluate the early results in a 1.5-year follow-up.

RESULTS

We found a significant improvement in parameters of quality of life, functionality, clinical and radiological angulation and angles following the definition of Paley et al., with a complication rate of 4 % under 88 osteotomies (Paley et al Orthop Clin North Am 25(3):425-65, 1994).

CONCLUSION

The described operative therapy shows to be sufficient and with satisfactory results in correcting rickets-related leg deformities under rural circumstances with low availability of medical resources.

Results of deformity correction in children with X-linked hereditary hypophosphatemic rickets by external fixation or combined technique

BACKGROUND

The operative procedures to correct multiplanar bone deformities may be indicated for prevention of secondary orthopaedic complications in children with X-linked hereditary hypophosphatemic rickets (XHPR). Different problems related to surgical correction were reported: increased rate of non-union, delayed union, recurrent deformity, deep intramedullary infection, refracture, nerve palsy, and pin tract infection. The aim of this retrospective study was comparison of results of correction in children with XHPR who underwent the treatment with either the Ilizarov device alone or a combined technique: the Ilizarov fixator with flexible intramedullary nailing (FIN) with hydroxyapatite bioactive coating and FIN.

MATERIAL AND METHODS

We retrospectively analysed 47 cases (children of age under 14 years) affected by XHPR. Simultaneous deformity correction in femur and tibia was performed with the Ilizarov device (group I) or the combined method (group II). This article is based on the results of a historical comparative retrospective study from the same institution.

RESULTS

The duration of external fixation is noted to be shorter applying the combined technique: 124.7 days (group I) vs 87.4 days (group II). In both groups deformity correction was achieved with a proper alignment. Nevertheless, while a child continues to grow during long-term follow-up, deviations of the mechanic axis from the centre of the knee joint have been developing again and values of mLDFA, mMPTA have become pathologic in the most of the cases. In group I location of a newly developed deformity resembled a pre-operative one, whereby both diaphyseal and metaphyseal parts were deformed. In group II in all the cases an apex of deformity was located in distal metadiaphyseal zone of the femur and proximal metadiaphyseal zone of the tibia. It is important to note that all of those in group II were out of the zone of the intramedullary nail.

CONCLUSION

Simultaneous correction of femoral and tibial deformities by means of circular external fixators is preferable. Application of a combined osteosynthesis allows to considerably reduce the duration of external fixation and decrease the number of complications. There were no recurrent deformities in parts of bone reinforced by intramedullary nails.

Contemporary Medical and Surgical Management of X-linked Hypophosphatemic Rickets

X-linked hypophosphatemia is an inheritable disorder of renal phosphate wasting that clinically manifests with rachitic bone pathology. X-linked hypophosphatemia is frequently misdiagnosed and mismanaged. Optimized medical therapy is the cornerstone of treatment. Even with ideal medical management, progressive bony deformity may develop in some children and adults. Medical treatment is paramount to the success of orthopaedic surgical procedures in both children and adults with X-linked hypophosphatemia. Successful correction of complex, multiapical bone deformities found in patients with X-linked hypophosphatemia is possible with careful surgical planning and exacting surgical technique. Multiple methods of deformity correction are used, including acute and gradual correction. Treatment of some pediatric bony deformity with guided growth techniques may be possible.

Therapeutic management of hypophosphatemic rickets from infancy to adulthood

In children, hypophosphatemic rickets (HR) is revealed by delayed walking, waddling gait, leg bowing, enlarged cartilages, bone pain, craniostenosis, spontaneous dental abscesses, and growth failure. If undiagnosed during childhood, patients with hypophosphatemia present with bone and/or joint pain, fractures, mineralization defects such as osteomalacia, entesopathy, severe dental anomalies, hearing loss, and fatigue. Healing rickets is the initial endpoint of treatment in children. Therapy aims at counteracting consequences of FGF23 excess, i.e. oral phosphorus supplementation with multiple daily intakes to compensate for renal phosphate wasting and active vitamin D analogs (alfacalcidol or calcitriol) to counter the 1,25-diOH-vitamin D deficiency. Corrective surgeries for residual leg bowing at the end of growth are occasionally performed. In absence of consensus regarding indications of the treatment in adults, it is generally accepted that medical treatment should be reinitiated (or maintained) in symptomatic patients to reduce pain, which may be due to bone microfractures and/or osteomalacia. In addition to the conventional treatment, optimal care of symptomatic patients requires pharmacological and non-pharmacological management of pain and joint stiffness, through appropriated rehabilitation. Much attention should be given to the dental and periodontal manifestations of HR. Besides vitamin D analogs and phosphate supplements that improve tooth mineralization, rigorous oral hygiene, active endodontic treatment of root abscesses and preventive protection of teeth surfaces are recommended. Current outcomes of this therapy are still not optimal, and therapies targeting the pathophysiology of the disease, i.e. FGF23 excess, are desirable. In this review, medical, dental, surgical, and contributions of various expertises to the treatment of HR are described, with an effort to highlight the importance of coordinated care.