The Danish child and parent Gait Outcomes Assessment List questionnaires were reliable and valid for cerebral palsy.

AIM: We investigated the reliability and validity of the Danish child and parent versions of the Gait Outcomes Assessment List (GOAL) questionnaires for ambulatory children with cerebral palsy (CP). METHODS: Translation and cultural adaptations were performed and content validity evaluated. Participants were enrolled between 2016 and 2018 from Aarhus University Hospital, Denmark. Children and parents completed the GOAL questionnaires twice for test-retest reliability. Discriminative validity was evaluated by comparing the child and parent GOAL scores between children with Gross Motor Function Classification System (GMFCS) levels I and II. The concurrent validity of the GOAL questionnaires were investigated by comparing them with Challenge-20, which assesses motor skills in children with CP. RESULTS: We studied 59 children (57% boys) with CP and GMFCS I-II at a mean age of 10.6 years. Test-retest intra-class correlations were excellent for the children (0.91, 95% confidence interval (CI) 0.83-0.96) and good for the parents (0.83, 95% CI 0.67-0.91). GOAL scores decreased with increasing GMFCS (p < 0.05). Both versions correlated well. The mean children's scores were significantly (6.2/100) higher than the parents' (p < 0.001). The GOAL scores correlated positively with Challenge-20. CONCLUSION: The Danish GOAL child and parent questionnaires demonstrated good reliability and content and discriminative and concurrent validity.

Team-based digital communication reduced patient-initiated phone calls to the hospital and improved patient satisfaction after orthopedic surgery: a randomized controlled trial in 70 patients.

BACKGROUND AND PURPOSE: Post-discharge inquiries to the hospital are predominantly conducted through phone calls. The rigid timing of these calls is inconvenient for patients and disrupts the workflows of healthcare professionals. The aim of this study was to investigate the effect of a team-based digital communication intervention (eDialogue) facilitated through a messenger-like commercial solution on patient-initiated phone calls to the hospital after discharge. Secondarily, we investigated other patient-initiated contacts, patients' perception of continuity of care, and their perception of feeling safe and satisfied after hospital discharge. METHODS: On the day of discharge, 70 surgically treated orthopedic patients were randomized to the intervention group with access to eDialogue (n = 35) or the control group with standard communication pathways by phone call (n = 35) for the following 8 weeks. Through eDialogue, the intervention group had access to team-based asynchronous digital communication in text and photos with healthcare professionals across disciplines and sectors. Inclusion criteria were discharge to own home and receipt of rehabilitation services from both hospital and primary care after discharge. RESULTS: We found a significant reduction in the mean number of patient-initiated phone calls to the hospital from 2.3 (95% confidence interval [CI] 1.4-4.1) in the control group to 0.5 (CI 0.3-1.0) in the intervention group (P = 0.004). Across groups, patients reported similar perceptions of continuity of care; however, the participants in the intervention group expressed significantly improved perceptions of, and satisfaction with, access to healthcare after discharge. CONCLUSION: Access to eDialogue reduced patient-initiated phone calls to the hospital, enhanced patient satisfaction with healthcare accessibility, and did not compromise patients' perception of continuity of care after discharge compared with standard communication pathways.

Accelerations Recorded by Simple Inertial Measurement Units with Low Sampling Frequency Can Differentiate between Individuals with and without Knee Osteoarthritis: Implications for Remote Health Care.

Determining the presence and severity of knee osteoarthritis (OA) is a valuable application of inertial measurement units (IMUs) in the remote monitoring of patients. This study aimed to employ the Fourier representation of IMU signals to differentiate between individuals with and without knee OA. We included 27 patients with unilateral knee osteoarthritis (15 females) and 18 healthy controls (11 females). Gait acceleration signals were recorded during overground walking. We obtained the frequency features of the signals using the Fourier transform. The logistic LASSO regression was employed on the frequency domain features as well as the participant's age, sex, and BMI to distinguish between the acceleration data from individuals with and without knee OA. The model's accuracy was estimated by 10-fold cross-validation. The frequency contents of the signals were different between the two groups. The average accuracy of the classification model using the frequency features was 0.91 ± 0.01. The distribution of the selected features in the final model differed between patients with different severity of knee OA. In this study, we demonstrated that using logistic LASSO regression on the Fourier representation of acceleration signals can accurately determine the presence of knee OA.

Complications and risk factors of intramedullary bone lengthening nails: a retrospective multicenter cohort study of 314 FITBONE and PRECICE nails.

BACKGROUND AND PURPOSE: Intramedullary bone-lengthening nails have become increasingly popular. The 2 most used and successful nails are the FITBONE and the PRECICE nails. Uniform reporting is lacking on complications of intramedullary bone-lengthening nails. The purpose was therefore to assess and categorize the complications of lower limb bone-lengthening nails and investigate risk factors. PATIENTS AND METHODS: We performed a retrospective review of patients operated on with intramedullary lengthening nails at 2 hospitals. We included only lower limb lengthening with FITBONE and PRECICE nails. Recorded patient data was patient demographics, nail information, and any complication. Complications were graded according to severity and origin classification. Complication risk factors were assessed with modified Poisson regression. RESULTS: 314 segments in 257 patients were included. The FITBONE nail was predominantly used (75%), and most of the lengthenings were performed in the femur (80%). 53% of the patients had complications. 269 complications were identified in 175 segments (144 patients). Device-related complications were most frequent (0.3 complications/segment), followed by joint complications (0.2 complications/segment). An increased relative risk was found for complications in the tibia compared with the femur and for age groups above 30 years compared with the 10-19 years group. CONCLUSION: Complications with intramedullary bone lengthening nails were more frequent than has previously been reported, with 53% of patients sustaining a complication. Future studies need to document the complications meticulously so that the true risk can be established.

Birthweight correlates to pubo-femoral distances and α angles in hip ultrasound of newborns at 6 weeks of age: a retrospective cohort study.

BACKGROUND AND PURPOSE: There is inconsistency in the literature regarding the relationship between increased birthweight and risk of developmental dysplasia of the hip (DDH). We aimed to investigate the correlation between birthweight and pubo-femoral distance (PFD), as well as Graf's α angle in newborns undergoing hip ultrasound examination at 6 weeks of age. PATIENTS AND METHODS: Basic newborn characteristics and ultrasound measurements were retrospectively collected during a 1-year study period. We excluded multiple births, newborns born at less than 37 gestational weeks, and incomplete information. Simple and multiple linear regression analyses were performed to evaluate the correlation of birthweight and PFD, and, second, birthweight and α angles including a stratified regression analysis investigating the potential effect modification of sex. RESULTS: 707 newborns (1,414 hips) were included. Mean birthweight was significantly higher for male newborns (P < 0.001). Increased birthweight was positively correlated to PFD values (crude coefficient 0.21, 95% confidence interval [CI] 0.10-0.32) and the correlation was still present after adjusting for sex, family history, and breech presentation (adjusted coefficient 0.18, CI 0.07-0.29). The stratified α angle model for the males was significant for both the crude coefficient (-0.73, CI -1.28 to -0.19) and the adjusted (-0.59, CI -1.15 to -0.03), and also for the females (crude coefficient -1.14, CI -1.98 to -0.31 and adjusted coefficient -1.15, CI -1.99 to -0.31). CONCLUSION: We found that increased birthweight positively correlated to PFD, and negatively correlated to α angle, but this was not of clinical significance.

Immunophenotypically defined stem cell subsets in paediatric AML are highly heterogeneous and demonstrate differences in BCL-2 expression by cytogenetic subgroups.

In adult acute myeloid leukaemia (AML), immunophenotypic differences enable discrimination of leukaemic stem cells (LSCs) from healthy haematopoietic stem cells (HSCs). However, immunophenotypic stem cell characteristics are less explored in paediatric AML. Employing a 15-colour flow cytometry assay, we analysed the expression of eight aberrant surface markers together with BCL-2 on CD34+ CD38- bone marrow stem cells from 38 paediatric AML patients and seven non-leukaemic, age-matched controls. Furthermore, clonality was investigated by genetic analyses of sorted immunophenotypically abnormal stem cells from six patients. A total of 50 aberrant marker positive (non-HSC-like) subsets with 41 different immunophenotypic profiles were detected. CD123, CLEC12A, and IL1RAP were the most frequently expressed markers. IL1RAP, CD93, and CD25 expression were not restricted to stem cells harbouring leukaemia-associated mutations. Differential BCL-2 expression was found among defined cytogenetic subgroups. Interestingly, only immunophenotypically abnormal non-HSC-like subsets demonstrated BCL-2 overexpression. Collectively, we observed pronounced immunophenotypic heterogeneity within the stem cell compartment of paediatric AML patients. Additionally, certain aberrant markers used in adults seemed to be ineligible for detection of leukaemia-representing stem cells in paediatric patients implying that inference from adult studies must be done with caution.

Criterion Validity of Linear Accelerations Measured with Low-Sampling-Frequency Accelerometers during Overground Walking in Elderly Patients with Knee Osteoarthritis.

Sensors with a higher sampling rate produce higher-quality data. However, for more extended periods of data acquisition, as in the continuous monitoring of patients, the handling of the generated big data becomes increasingly complicated. This study aimed to determine the validity and reliability of low-sampling-frequency accelerometer (SENS) measurements in patients with knee osteoarthritis. Data were collected simultaneously using SENS and a previously validated sensor (Xsens) during two repetitions of overground walking. The processed acceleration signals were compared with respect to different coordinate axes to determine the test-retest reliability and the agreement between the two systems in the time and frequency domains. In total, 44 participants were included. With respect to different axes, the interclass correlation coefficient for the repeatability of SENS measurements was [0.93-0.96]. The concordance correlation coefficients for the two systems' agreement were [0.81-0.91] in the time domain and [0.43-0.99] in the frequency domain. The absolute biases estimated by the Bland-Altman method were [0.0005-0.008] in the time domain and [0-0.008] in the frequency domain. Low-sampling-frequency accelerometers can provide relatively valid data for measuring the gait accelerations in patients with knee osteoarthritis and can be used in the future for remote patient monitoring.

Positive predictive values in clinical screening for developmental dysplasia of the hip.

AIM: To establish the positive predictive value (PPV) of clinical hip examinations performed by referrers in the Danish screening programme for Developmental Dysplasia of the Hip (DDH) utilising three definitions of true positive DDH diagnosis. METHODS: We retrospectively identified 290 children (169 female) referred during a 4-year period to the orthopaedic outpatient clinic at our institution with a positive clinical hip examination. Positive predictive value was calculated for clinical hip examinations across three definitions of a true positive clinical hip examination for all referrers and subgroups consisting of general practitioners, midwives and paediatricians. The PPV for clinical hip examinations was calculated for paediatric orthopaedic surgeons using one of the three definitions. RESULTS: Positive predictive value of clinical hip examinations for all referrers were 5.4%, 3.6% and 1.8% with the definition of a true positive DDH diagnosis defined as clinical instability found by orthopaedic surgeon, ultrasound classification ≥Graf IIc or both definitions combined, respectively. Positive predictive value of clinical hip examinations performed by orthopaedic surgeons was 33.3% with a true positive clinical examination defined as an ultrasound classification ≥Graf IIc. CONCLUSION: We conclude that the positive predictive value of clinical hip examinations made by referrers in the Danish screening programme for DDH is low.

Complications common in motorized intramedullary bone transport for non-infected segmental defects: a retrospective review of 15 patients.

Background and purpose - Since the introduction of intramedullary bone transport nails only very few cases have been reported in the literature. Thus we evaluated the results and complications in a single institution retrospective cohort.Patients and methods - 15 (median age 40 years (18-70), 8 males) consecutive patients, were included and the electronic patient records and radiographs were reviewed. Complications were severity graded and categorized as device or non-device related.Results - The segmental bone loss was due to non-union site in 8 femurs and 4 tibias, or traumatic bone loss in 2 femurs and 1 tibia. The segmental bone defect was a median of 3 cm (0.5-10). 9 of 10 femoral cases and 4 of 5 tibial cases healed with the bone transport nail. All 15 patients had a healed docking site and regenerate at the end of treatment after a median of 13 months (6-38). 24 complications (15 device related and 9 non-device related) occurred in 11/15 patients with a minimum follow-up of 6 months after nail removal. The number of unplanned surgeries due to device related complications was: 0 in 9 patients, 1 in 3 patients, 2 in 1 patient, 3 in 2 patients.Interpretation - Segmental bone defects can heal with a bone transport nail. However, the number of complications was high and 15 out of 24 complications were devicerelated. Optimizing nail design is therefore needed to reduce complications in intramedullary bone transport.

Systematic review of complications with externally controlled motorized intramedullary bone lengthening nails (FITBONE and PRECICE) in 983 segments.

Background and purpose - In recent years motorized intramedullary lengthening nails have become increasingly popular. Complications are heterogeneously reported in small case series and therefore we made a systematic review of complications occurring in lower limb lengthening with externally controlled motorized intramedullary bone lengthening nails.Methods - We performed a systematic search in PubMed, EMBASE, and the Cochrane Library with medical subject headings: Bone Nails, Bone Lengthening, and PRECICE and FITBONE nails. Complications were graded on severity and origin.Results - The search identified 952 articles; 116 were full text screened, and 41 were included in the final analysis. 983 segments were lengthened in 782 patients (age 8-74 years). The distribution of nails was: 214 FITBONE, 747 PRECICE, 22 either FITBONE or PRECICE. Indications for lengthening were: 208 congenital shortening, 305 acquired limb shortening, 111 short stature, 158 with unidentified etiology. We identified 332 complications (34% of segments): Type I (minimal intervention) in 11% of segments; Type II (substantial change in treatment plan) in 15% of segments; Type IIIA (failure to achieve goal) in 5% of segments; and Type IIIB (new pathology or permanent sequelae) in 3% of segments. Device and bone complications were the most frequent.Interpretation - The overall risk of complications was 1 complication for every 3 segments lengthened. In 1 of every 4 segments, complications had a major impact leading to substantial change in treatment, failure to achieve lengthening goal, introduction of a new pathology, or permanent sequelae. However, as no standardized reporting method for complications exists, the true complication rates might be different.

What is the association between MRI and conventional radiography in measuring femoral head migration?

Background and purpose - Pelvic radiographs are traditionally used for assessing femoral head migration in residual acetabular dysplasia (RAD). Knowledge of the heightened importance of cartilaginous structures in this condition has led to increased use of MRI in assessing both osseous and cartilaginous structures of the pediatric hip. Therefore, we assessed the relationship between migration percentages (MP) found on MRI and conventional radiographs. Second, we analyzed the reliability of MP in MRI and radiographs.Patients and methods - We retrospectively identified 16 patients (mean age 5 years [2-8], 14 girls), examined for RAD during a period of 2½ years. 4 raters performed blinded repeated measurements of osseous migration percentage (MP) and cartilaginous migration percentage (CMP) in MRI and radiographs. Pelvic rotation and tilt indices were measured in radiographs. Bland-Altman (B-A) plots and intraclass correlation coefficients (ICC) were calculated for agreement and reliability.Results - B-A plots for MPR and MPMRI produced a mean difference of 6.4 with limits of agreement -11 to 24, with higher disagreements at low average MP values. Mean MPR differed from mean MPMRI (17% versus 23%, p < 0.001). MPR had the best interrater reliability with an ICC of 0.92 (0.86-0.96), compared with MPMRI and CMP with ICC values of 0.61 (0.45-0.70) and 0.52 (0.26-0.69), respectively. Intrarater reliability for MPR, MPMRI and CMP all had ICC values above 0.75 and did not differ statistically significantly. Differences inMPMRI and MPR showed no correlation to pelvic rotation index, pelvic tilt index, or interval between radiograph and MRI exams.Interpretation - Pelvic radiographs underestimated MP when compared with pelvic MRI. We propose CMP as a new imaging measurement, and conclude that it has good intrarater reliability but moderate interrater reliability. Measurement of MP in radiographs and MRI had mediocre to excellent reliability.

Comparison of histomorphometric and radiographic effects of growth guidance with tension-band devices (eight-Plate and FlexTack) in a pig model.

Background and purpose - Temporary hemiepiphysiodesis for growth modulation in skeletally immature patients is a long-known technique. Recently the use of tension-band devices has become popular. This study compares 2 tension-band implants (eight-Plate and FlexTack) regarding their effects on the growth plate.Animals and methods - 12 pigs in 2 equally sized groups (A and B) were investigated. The right proximal medial tibia was treated with either eight-Plate or FlexTack. The left tibia of the same pig was treated with the opposite implant. After 9 weeks all implants were removed. Animals in group B were then hosted for another 5 weeks. Histomorphometric analysis of the growth plate was carried out after 9 and 14 weeks, respectively. Radiographs were taken at implantation, removal, and after 14 weeks.Results - Both tension-band devices achieved a statistically significant and clinically relevant growth inhibition, whereas the effect appeared to be more distinct after the use of FlexTack. Implant-related complications or physeal damage was not observed. After implant removal, rebound phenomenon was radiologically observed in all cases. The growth plates treated with eight-Plate showed a paradox reversal of the zonal distributions, with an increase of the proliferative zones at the previously arrested medial aspect of the physis and a decrease laterally.Interpretation - Both eight-Plate and FlexTack proved to be appropriate devices for growth-guiding treatment. The radiographic evaluation showed a change in angular axes after treatment with each implant, while the correction appeared to be faster with FlexTack. The paradox cartilaginous reaction observed after removal of the eight-Plate might be a histopathological correlate for rebound phenomenon.

Superior fixation and less periprosthetic stress-shielding of tibial components with a finned stem versus an I-beam block stem: a randomized RSA and DXA study with minimum 5 years' follow-up.

Background and purpose - The stem on the tibial component of total knee arthroplasty provides mechanical resistance to lift-off, shear forces, and torque. We compared tibial components with finned stems (FS) and I-beam block stems (IS) to assess differences in implant migration. Patients and methods - In a patient-blinded RCT, 54 patients/knees (15 men) with knee osteoarthritis at a mean age of 77 years (70-90) were randomly allocated to receive tibial components with either a FS (n = 27) or an IS (n = 27). Through 5 to 7 years' follow-up, implant migration was measured with RSA, periprosthetic bone mineral density (BMD) was measured with DXA, and surgeons reported American Knee Society Score (AKSS). Results - At minimum 5 years' follow-up, maximum total point motion (MTPM) was higher (p = 0.04) for IS (1.48 mm, 95% CI 0.81-2.16) than for FS (0.85 mm, CI 0.38-1.32) tibial components. Likewise, total rotation (TR) was higher (p = 0.03) for IS (1.51˚, CI 0.78-2.24) than for FS (0.81˚, CI 0.36-1.27). Tibial components with IS externally rotated 0.50° (CI -0.06 to 1.06) while FS internally rotated 0.09° (CI -0.20 to 0.38) (p = 0.03). Periprosthetic bone stress-shielding was higher (p < 0.01) up to 2 years' follow-up for IS compared with FS in the regions medial to the stem (-13% vs. -2%) and posterior to the stem (-13% vs. -2%). Below the stem bone loss was also higher (p = 0.01) for IS compared with FS (-6% vs. +1%) up to 1-year follow-up. Knee score improved similarly in both groups up to 5 years' follow-up. Interpretation - Periprosthetic bone stress-shielding medial and posterior to the stem until 2 years, and tibial component migration at 5 years, was less for a finned compared with an I-shaped block stem design.

Suggestion for new 4.4 mm pubo-femoral distance cut-off value for hip instability in lateral position during DDH screening.

Background and purpose - Current selective screening algorithms for developmental dysplasia of the hip (DDH) are insufficient. Universal screening programs have been proposed but so far have been deemed too expensive and time consuming. The pubo-femoral distance may solve this problem as a quick, low-cost, highly sensitive, and specific sonographic measurement for DDH, but this has only been validated in the supine position. Therefore we validated pubo-femoral distance (PFD) in the lateral position as an indicator for instability of the hip. Methods - All participants had undergone ultrasonographic diagnostics using the modified Graf technique. In addition, PFD measurements in lateral position were performed. Results were compared between 25 infants who had been treated for DDH because of dysplastic appearance on ultrasound combined with clinical instability and a control group consisting of 100 untreated infants screened for DDH. Sensitivity, specificity, and cut-off points were determined using Receiver operating characteristics (ROC) analysis. Results - We found a mean PFD of 6.8 mm (6.2-7.4) in the treated group with a control group PFD of 3.4 mm (3.3-3.6) (p < 0.005). A PFD value above a threshold of 4.4 mm yielded a sensitivity of 100% and a specificity of 93% for detecting unstable DDH. Interpretation - PFD measured in lateral position was statistically significantly increased in hips of children treated for DDH with Denis Browne hip brace compared with healthy children with unaffected stable hips. Furthermore, the PFD measurement had a high level of sensitivity and specificity at a cut-off value of 4.4 mm. A cut-off value of 6.00 mm has previously been reported as the gold standard in supine position. We suggest that 4.4 mm is used in lateral position.

Topical zoledronic acid decreases micromotion induced bone resorption in a sheep arthroplasty model.

BACKGROUND: Initial micromotion of a total hip replacement is associated with aseptic loosening. The use of bisphosphonates could be one way to reduce peri-implant bone resorption induced by micromotion. Bisphosphonates compounds are inhibitors of bone resorption. The aim of this study was to investigate whether local treatment with bisphosphonate would reduce bone resorption and fibrous tissue around an experimental implant subjected to micromotion. METHODS: One micromotion implant were inserted into each medial femoral condyle in ten sheep. During each gait cycle the implant axially piston 0.5 mm. During surgery one of the femoral condyles were locally treated with 0.8 mg zoledronate. The other condyle served as control. Observation period was 12 weeks. RESULTS: Histological evaluation showed a fibrous capsule around both the control and bisphosphonate implants. Histomorphometrical analysis showed that 97% of the surface on both control and bisphosphonate implants were covered by fibrous tissue. However, the bisphosphonate was able to preserve bone in a 1 mm zone around the implants. CONCLUSION: This study indicates that local treatment with bisphosphonate cannot prevent the formation of a fibrous capsule around an implant subjected to micromotion, but bisphosphonate is able to reduce resorption of peri-prosthetic bone.

Epidural analgesia is superior to local infiltration analgesia in children with cerebral palsy undergoing unilateral hip reconstruction.

BACKGROUND AND PURPOSE: Treatment of postoperative pain in children with cerebral palsy (CP) is a major challenge. We investigated the effect of epidural analgesia, high-volume local infiltration analgesia (LIA), and an approximated placebo control on early postoperative pain in children with CP who were undergoing unilateral hip reconstruction. PATIENTS AND METHODS: Between 2009 and 2014, we included 18 children with CP. The first part of the study was a randomized double-blind trial with allocation to either LIA or placebo for postoperative pain management, in addition to intravenous or oral analgesia. In the second part of the study, the children were consecutively included for postoperative pain management with epidural analgesia in addition to intravenous or oral analgesia. The primary outcome was postoperative pain 4 h postoperatively using 2 pain assessment tools (r-FLACC and VAS-OBS) ranging from 0 to 10. The secondary outcome was opioid consumption over the 21-h study period. RESULTS: The mean level of pain 4 h postoperatively was lower in the epidural group (r-FLACC: 0.7; VAS-OBS: 0.6) than in both the LIA group (r-FLACC: 4.8, p = 0.01; VAS-OBS: 5.2, p = 0.02) and the placebo group (r-FLACC: 5.2, p = 0.01; VAS-OBS: 6.5, p < 0.001). Corrected for body weight, the mean opioid consumption was lower in the epidural group than in the LIA group and the placebo group (both p < 0.001). INTERPRETATION: Epidural analgesia is superior to local infiltration analgesia for early postoperative pain management in children with cerebral palsy who undergo unilateral hip reconstruction.

Accuracy of MR in growth plate measurement.

PURPOSE: To analyze the accuracy of growth-plate thickness measurements detected on 1.5-T and 7-T MR images using histology sections as a standard of reference. MATERIALS AND METHODS: Four defrosted pig tibiae were 1.5-T MR scanned and one fresh tibia was 7-T MR scanned. The height of the growth plate was measured and compared to histology. RESULTS: Histology measurements showed a mean growth plate thickness of 467 µm (SD = 82.2). The mean growth plate thickness measured in the 7-T MR images was 465 µm (SD = 62.2) and 1,325 µm (SD = 183.5) on 1.5-T MR measurements. We found a better correspondence between the growth plate thickness measured on the 7-T MR and histology samples compared to 1.5 T. CONCLUSIONS: The growth plate can be identified and measured with high accuracy using 7-T MR. 1.5-T MR can only describe some morphological characteristics.

Thermal epiphysiodesis performed with radio frequency in a porcine model.

BACKGROUND AND PURPOSE: Current techniques for epiphysiodesis involve opening of cortical windows; use of staples, screws, and tension devices; and fusion with curettes or drills. Complications may have serious consequences. There is a need for a more reliable, precise, and less traumatic procedure that overcomes the known complications from existing techniques. We analyzed a new epiphysiodesis technique using radio-frequency ablation (RFA) in a porcine model. METHODS: Six 35-kg and two 25-kg immature pigs were used. 1 hind leg of each animal was randomly selected and the proximal tibia growth plate was ablated laterally and medially. The contralateral leg was used as a control. MR images were obtained immediately after the ablation and 12 weeks later for 6 animals, and 24 weeks later for the other 2 animals. CT was done for the 2 animals that were followed for 24 weeks for proof of bone bridges. RESULTS: Both tibias were equal in length initially. At the 12-week follow-up, there was an average leg length discrepancy of 3.9 mm (95% CI: 3.0-4.8), and at 24 weeks the difference was 8.4 mm and 7.5 mm. No damage to the adjacent tissue was found. Bone bridges and physeal closure were found after 24 weeks. The pigs showed no discomfort after the intervention. INTERPRETATION: We found RFA to be feasible for epiphysiodesis in a pig model. The method is minimally invasive and recovery may be quick compared to conventional methods. We recommend that the method should be tested in larger-scale safety studies before clinical application.

Are percutaneous epiphysiodesis and Phemister technique effective in the treatment of leg-length discrepancy? A systematic review.

Epiphysiodesis is considered the preferred treatment for children predicted to have leg length discrepancies (LLDs) 2-5 cm at maturity. The aim of this study was to systematically review the existing literature on the effectiveness of permanent epiphysiodesis for LLD treatment, and secondarily to address the reported complications of permanent epiphysiodesis techniques. This systematic review was performed according to PRISMA guidelines. We searched MEDLINE (PubMed), Embase, Cochrane Library, Web of Science and Scopus for studies on skeletally immature patients with LLD treated with permanent epiphysiodesis. The extracted outcome categories were effectiveness of epiphysiodesis (LLD measurements pre/post-operatively, successful/unsuccessful), physeal fusion/arrest, and complications that were graded on severity. Forty-nine studies (3051 patients) were included, 1550 underwent Phemister/modified Phemister epiphysiodesis and 1501 percutaneous epiphysiodesis (PE). Total successful permanent epiphysiodesis surgeries (16 studies) were 73.7% (516/700). Only 13 out of 23 studies had a mean final LLD of less than 1.5 cm. In total, 17.5% (513/2936) of complications were reported. 57 angular deformities were reported (1.9%). Phemister technique had higher percentage of complications (39%) than PE (19.1%) in total, but when failure to achieve adequate reduction in LLD was not included, complication rates for both were close to 14%. However, severe complications were 10.2% for Phemister group and 5.1% for PE. The high complication rates and the relative low success rate call for optimization of the timing and the applied techniques when treating LLD with permanent epiphysiodesis. Phemister technique was found to have higher percentage of severe complications than PE. Registration: PROSPERO (CRD42023435177).