Leg length discrepancies (LLD): An etiology to be considered in its proper measure. A critical and historical review.

INTRODUCTION: Studies of leg-length discrepancies (LLD) have been the subject of debate for almost 200 years. A large number of studies have emerged, most frequently using assessment criteria based on painful symptoms or joint damage. DEVELOPMENT: While many authors argue for a threshold of 10-20 mm to establish a link between pain and LLD, most publications based on radiography show lesion stigmata on lumbar, hip and knee joints as early as 6 mm. This would be linked to comorbidities. DISCUSSION: Some studies argue forcefully that leg-length correction below 20 mm is of no benefit. The authors of the present article, on the other hand, evoke the notion of lesion risks in the absence of correction, even for small deviations in the presence of certain associated factors and according to their importance. CONCLUSION: The authors argue for the need to define in the future a lesion significance score that would not be correlated to painful symptomatology, but rather to the presence of co-morbidities such as age, anatomical variability, sports practice and/or patients' professional activities. Other parameters, such as mobility, should also be taken into consideration, while gender, height and weight do not appear to be significantly related.

Anthropometric profile of leg length inequality and its impact on gait / Perfil antropométrico de la desigualdad en la longitud de las piernas y su impacto en la marcha

SUMMARY: Leg length inequality (LLI) affects gait - primarily pelvic and torso movements. LLI is present in around 40-70 % of the healthy population. Due to LLI's significant impact on the body, as well as the possible occurrence of a variety of associated health problems, the aim of this research is to determine whether there is a significant difference in pelvic movement in all three planes, depending on the degree of LLI. This study was conducted on a sample of 30 healthy subjects. The functional length of lower limbs was measured. When LLI was calculated, kinematic measures were taken of pelvic and lower limb movements during gait using 3D cameras and ©Vicon Motion Systems Ltd. UK. The obtained data on kinematic pelvic movement in all three planes during gait were compared with the reference values. The results show that there is no statistically significant difference in pelvic movement about the axes x, y, and z in cases of LLI of up to 18mm (p>0,05). There is a statistically highly significant positive correlation between the difference in functional leg length (r=0,575; p=0,008) and femur length (r=0,525; p=0,015) on one hand, and the difference in pelvic movement about the axis x on the other, compared to the reference values. In a healthy population with LLI from 0 to 18 mm, gait remains unaffected and an increase in LLI predominantly affects pelvic movement about the horizontal axis (x) - pelvic tilt, which exponentially increases with an increase in femur length discrepancy.

La diferencia en la longitud de las piernas (LLI, por sus siglas en inglés) afecta la marcha, principalmente los movimientos pélvicos y del dorso. La LLI está presente en alrededor del 40-70 % de la población sana. Debido al importante impacto de LLI en el cuerpo, así como a la posible aparición de una variedad de problemas de salud asociados, el objetivo de esta investigación fue determinar si existe una diferencia significativa en el movimiento pélvico en los tres planos, dependiendo del grado de LLI. Este estudio se realizó en una muestra de 30 sujetos sanos. Se midió la longitud funcional de los miembros inferiores. Cuando se calculó el LLI, se tomaron medidas cinemáticas de los movimientos pélvicos y de los miembros inferiores durante la marcha utilizando cámaras 3D y ©Vicon Motion Systems Ltd. UK. Los datos obtenidos sobre el movimiento pélvico cinemático en los tres planos durante la marcha se compararon con los valores de referencia. Los resultados mostraron que no existe diferencia estadísticamente significativa en el movimiento pélvico sobre los ejes x, y, y z en casos de LLI de hasta 18 mm (p>0,05). Existe una correlación positiva estadísticamente muy significativa entre la diferencia en la longitud funcional de la pierna (r=0,575; p=0,008) y la longitud del fémur (r=0,525; p=0,015), y la diferencia en el movimiento pélvico sobre el eje x por otro, en comparación con los valores de referencia. En una población sana con LLI de 0 a 18 mm, la marcha no se ve afectada y un aumento en LLI afecta predominantemente el movimiento pélvico sobre el eje horizontal (x) - inclinación pélvica, que aumenta exponencialmente con un aumento en la discrepancia de longitud del fémur.

Overgrowth of the lower limb after treatment of developmental dysplasia of the hip: incidence and risk factors in 101 children with a mean follow-up of 15 years.

Background and purpose - There are few studies on overgrowth of the affected limb after treatment of developmental dysplasia of the hip (DDH). We investigated the incidence of overgrowth and its risk factors in DDH patients.Patients and methods - 101 patients were included in this study. Overgrowth was defined by 2 criteria: when the height of the femoral head of the affected side was higher than that of the contralateral side by more than 10 mm, or by more than 15 mm. The potential risk factors of distinct overgrowth were retrospectively examined using multivariable analysis.Results - When overgrowth was defined as femoral head height difference (FHHD) > 10 mm, its incidence was 44%, and only femoral osteotomy was identified as a significant risk factor with a relative risk (RR) of 1.6 (95% confidence interval [CI] 1.0-2.5). When overgrowth was defined as FHHD > 15 mm, its incidence was 23%, and femoral osteotomy was identified as the only significant risk factor with an RR of 2.3 (CI 1.2-4.5). Overgrowth developed more frequently in patients who underwent femoral osteotomy at the age of 2 to 4 years (87%) than in the others (46%) (p = 0.04).Interpretation - Overgrowth of the affected limb is common in DDH patients. Patients who underwent femoral osteotomy, especially at the age of 2 to 4 years, may require careful follow-up because of the substantial risk for overgrowth.

Influence of leg length inequalities on pelvis and spine in patients with total hip arthroplasty.

BACKGROUND: Leg length inequalities (LLIs) are a common finding in patients with a total hip arthroplasty (THA). Therefore, we compared the effects of simulated LLIs in patients with total hip arthroplasty (THA) with a matched control group. RESEARCH QUESTION: Do LLIs lead to different effects on the musculoskeletal apparatus of patients with a THA then in a control group? METHODS: In 99 patients with a THA the effects of simulated LLIs were compared to a matched control group of 101 subjects without a hip arthroplasty. First, we compared methods for LLI quantification (tape measurements, pelvic x- ray and rasterstereography). Second, the effects of simulated LLIs on the spine and pelvis were evaluated in both groups using surface topography. LLIs of 5, 10, 15, 20 and 30 mm were simulated on both sides with a simulation platform. The changes of pelvic position (pelvic obliquity & pelvic torsion) and the effects on spinal posture (surface rotation & lateral deviation) were measured and analysed using a surface topography system. RESULTS: Mean LLI measured with a tape was 0.9 mm (SD +/- 14.8). Mean pelvic obliquity measured on x-rays was 1.2 mm (SD +/- 11.6) and with surface topography 0.9 mm (SD +/- 7.9). Simulated LLIs resulted in significant changes of pelvic position and spinal posture in the patient and control group. Interestingly, our study showed that simulated LLIs lead to greater changes in pelvic position (p<0.05) in patients with a THA. SIGNIFICANCE: This is the first study to demonstrate that LLIs might have a greater impact on the pelvic position of THA patients than in native hips, which could indicate that LLIs do need to be compensated differently in patients with THA than in patients without a THA.

Transphyseal anterior cruciate ligament reconstruction in adolescents with substantial remaining growth causes temporary growth arrest resulting in subclinical leg-length discrepancy.

The purpose of the present study was to investigate the characteristics of growth disturbances in patients with remaining growth after transphyseal anterior cruciate ligament (ACL) reconstruction who were confirmed to have no definite postoperative physeal abnormalities on magnetic resonance imaging (MRI).Forty adolescents (mean age 15.6 ±â€Š1.0 years [range 12.2-16.8], mean follow-up 2.7 ±â€Š0.7 years [range 2.0-5.5 years]), who underwent transphyseal ACL reconstruction and were confirmed to have no focal physeal disruptions on follow-up MRIs 6 to 12 months after the operation, were retrospectively evaluated. The patients were grouped according to the leg-length growth of the uninjured side, measured on scanograms, obtained before surgery, and at the final follow-up.Leg-length discrepancies (LLD) at the last follow-up were greater in patients with leg growth ≥4 cm than in those with leg growth <4 cm (5.3 ±â€Š9.0 mm vs -0.3 ±â€Š4.2 mm, P = .033); however, no significant difference was observed between subgroup patients with leg growth of 4 to 6 cm or ≥6 cm (5.6 ±â€Š10.4 mm vs 4.8 ±â€Š7.0 mm, P = .958). On multivariate analysis, leg growth was a significant predictive factor for the final LLD (P = .030).Adolescents with additional leg-length growth after transphyseal ACL reconstructions presented with greater LLDs (as shown in the <4 cm vs ≥4 cm groups), but they also presented a ceiling effect (as shown in the 4-6 cm vs ≥6 cm subgroups). Transphyseal ACL reconstructions appeared to cause temporary growth arrest/disturbances in patients with substantial remaining growth which then resumed resulting in clinically insignificant LLDs.

Z-plasty for severe gluteal muscle contracture in children.

PURPOSE: To review the records of 363 patients with severe gluteal muscle contracture to determine its mechanism, underlying pathology, and treatment outcome. METHODS: Records of 136 males and 227 females aged 5 to 18 (mean, 12.2) years who underwent Z-plasty for bilateral (n=347) or unilateral (n=16) severe gluteal muscle contracture were reviewed. Severe gluteal muscle contracture was classified as typical (n=52) or special (n=311). The typical type is associated with symptoms of positive out-toe gait, Ober sign, back-extending test, cross-leg test, squatting with knee side-by-side test, and hip dysfunction. It is further subdivided into mild (n=0), moderate (n=40), or severe (n=12). The special type is associated with additional symptoms of pelvic tilt and leg length discrepancy (<2 cm in 181 hips, 2-4 cm in 82 hips, and >4 cm in 48 hips). 311 hips had pelvic tilt and 47 hips had lumbar compensatory scoliosis. Treatment outcome was assessed at 6 months. Hip functional score was assessed at the final follow-up. RESULTS: The mean hospitalisation period was 11 days. After a mean follow-up of 1.5 years, the mean hip functional score improved from 8.03 to 11.69; improvement was higher in children (age 5-13 years) than in adolescents (age 14-18 years) [3.7 vs. 2.9, p<0.001]. At 6 months, outcome was excellent in 280 hips, good in 80, fair in 3 hips, and poor in 0. The 3 hips with fair outcome had persistent slight pelvic tilt and swaying gait. Two of them had preoperative leg length discrepancy >4 cm, and intra-operatively the contracture band severely affected the joint capsule. The third patient did not comply with postoperative exercises. CONCLUSION: Surgical treatment for severe gluteal muscle contracture achieved good outcome.

The comparative, long-term effect of the Salter osteotomy and Pemberton acetabuloplasty on pelvic height, scoliosis and functional outcome.

AIMS: This study compared the long-term results following Salter osteotomy and Pemberton acetabuloplasty in children with developmental dysplasia of the hip (DDH). We assessed if there was a greater increase in pelvic height following the Salter osteotomy, and if this had a continued effect on pelvic tilt, lumbar curvature or functional outcomes. PATIENTS AND METHODS: We reviewed 42 children at more than ten years post-operatively following a unilateral Salter osteotomy or Pemberton acetabuloplasty. We measured the increase in pelvic height and the iliac crest tilt and sacral tilt at the most recent review and at an earlier review point in the first decade of follow-up. We measured the lumbar Cobb angle and the Short Form-36 (SF-36) and Harris hip scores were collected at the most recent review. RESULTS: During the first decade of follow-up, there was a greater increase in pelvic height in the children who had a Salter osteotomy (Salter, 10.1%; Pemberton, 4.3%, p < 0.001). The difference in the increase in pelvic height was insignificant at the most recent review (Salter, 4.4%; Pemberton, 3.1%, p = 0.249). There was no significant difference between the two groups for the lumbar Cobb angle, (Salter, 3.1°; Pemberton, 3.3°, p = 0.906). A coronal lumbar curve was seen in 41 children (97%), 30 of these had a compensatory curve. Sacral tilt was the radiographic parameter for pelvic imbalance that correlated most with the lumbar Cobb angle (Pearson correlation co-efficient 0.59). The Harris hip score and SF-36 were good and showed no differences between the two groups. CONCLUSION: In the long-term, we found no difference in the functional results or pelvic imbalance between Salter osteotomy and Pemberton acetabuloplasty in the management of children with DDH. Cite this article: Bone Joint J 2016;98-B:1145-50.

Nail-medullary canal ratio affects mechanical axis deviation during femoral lengthening with an intramedullary distractor.

INTRODUCTION: Callus distraction of the femur using an intramedullary distractor has several advantages over the use of external fixators. However, difficulty in controlling the mechanical axis during lengthening may cause deformities and knee osteoarthritis. Purpose of the study is to answer the following questions: (1) is lengthening with an intramedullary device associated with a medial or lateral shift of the mechanical axis? (2) Which factors are associated with varisation/valgisation of the mechanical axis during lengthening? MATERIALS AND METHODS: We analysed pre-treatment and post-treatment radiographs from 20 patients who underwent unilateral femoral-lengthening procedures using intramedullary distractors. Patients with acute correction of pre-existing deformities or combined ipsilateral femoral and tibial lengthening were excluded. Mechanical axis deviations, osteotomy level, and nail-medullary canal ratio were recorded. RESULTS: Compared to the preoperative axis, the mechanical axis shifted medially in 7 patients (varisation group) and laterally in 13 patients (valgisation group). The groups did not significantly differ regarding preoperative leg length discrepancy (LLD), mechanical axis alignment, LLD-cause and implants used. The nail-medullary canal ratio significantly differed between groups (p<0.001), being <85% in the varisation group and >85% in the valgisation group. The distance between the lesser trochanter and the osteotomy site was significantly longer in the valgisation group (58.9±16.3mm, middle third of the femur) compared to the varisation group (40.6±11.4mm, proximal third of the femur; p=0.02). CONCLUSION: The nail-medullary canal ratio should be considered during preoperative planning. To avoid a varisation effect-for example, in cases with pre-existing varus alignment-it would be advisable to perform an osteotomy at the middle third of the femur with implantation of a nail that fully covers the medullary canal at the osteotomy site. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Comparison of lifts versus tape measure in determining leg length discrepancy.

OBJECTIVE: To evaluate the validity (accuracy) and reliability of 2 commonly used clinical methods, 1 indirect (lifts) and 1 direct (tape measure), for assessment of leg length discrepancy (LLD) in comparison to radiograph. METHODS: Twenty subjects suspected of having LLD participated in this study. Two clinical methods, 1 direct using a tape measure and 1 indirect using lifts, were standardized and carried out by 4 examiners. Difference in height of the femoral heads on standing pelvic radiograph was measured and served as the gold standard. RESULTS: The intraclass correlation coefficient assessing interobserver reliability was 0.737 for lifts and 0.477 for tape measure. The remainder of the analysis is based on the average of the measurements by the 4 examiners. Pearson correlation coefficients were 0.93 for the lifts and 0.75 for the tape measure method. Paired sample t tests showed difference in means of 2 mm (p = 0.051) for lifts and -5 mm (p = 0.007) for tape measure compared with radiograph. Sensitivity and specificity were 55% and 89% for lifts and 45% and 56% for tape measure, respectively, using > 5 mm as the definition for LLD. The wrong leg was identified as being shorter in 1 out of 20 subjects using lifts versus 7 out of 20 using tape measure. CONCLUSION: The indirect standing method of LLD measurement using lifts had superior validity, interobserver reliability, and specificity in comparison with radiograph over the direct supine method using tape measure. Both clinical methods underestimated LLD compared with radiograph.

microRNA alterations driving acute and late stages of radiation-induced fibrosis in a murine skin model.

PURPOSE: Although ionizing radiation is critical in treating cancer, radiation-induced fibrosis (RIF) can have a devastating impact on patients' quality of life. The molecular changes leading to radiation-induced fibrosis must be elucidated so that novel treatments can be designed. METHODS AND MATERIALS: To determine whether microRNAs (miRs) could be responsible for RIF, the fibrotic process was induced in the right hind legs of 9-week old CH3 mice by a single-fraction dose of irradiation to 35 Gy, and the left leg served as an unirradiated control. Fibrosis was quantified by measurements of leg length compared with control leg length. By 120 days after irradiation, the irradiated legs were 20% (P=.013) shorter on average than were the control legs. RESULTS: Tissue analysis was done on muscle, skin, and subcutaneous tissue from irradiated and control legs. Fibrosis was noted on both gross and histologic examination by use of a pentachrome stain. Microarrays were performed at various times after irradiation, including 7 days, 14 days, 50 days, 90 days, and 120 days after irradiation. miR-15a, miR-21, miR-30a, and miR-34a were the miRs with the most significant alteration by array with miR-34a, proving most significant on confirmation by reverse transcriptase polymerase chain reaction, c-Met, a known effector of fibrosis and downstream molecule of miR-34a, was evaluated by use of 2 cell lines: HCT116 and 1522. The cell lines were exposed to various stressors to induce miR changes, specifically ionizing radiation. Additionally, in vitro transfections with pre-miRs and anti-miRs confirmed the relationship of miR-34a and c-Met. CONCLUSIONS: Our data demonstrate an inverse relationship with miR-34a and c-Met; the upregulation of miR-34a in RIF causes inhibition of c-Met production. miRs may play a role in RIF; in particular, miR-34a should be investigated as a potential target to prevent or treat this devastating side effect of irradiation.

Management of nonunion of lower-extremity long bones using mono-lateral external fixator--report of 37 cases.

INTRODUCTION: The management of nonunion has remained a constant challenge. The associated bone defect, shortening, deformity and infection complicate the management. A mono-lateral external fixator may minimise some of the problems frequently encountered in these patients. We report our results of prospectively evaluated 37 consecutive patients regarding nonunion of lower-extremity long bones managed using a mono-lateral external fixator. PATIENTS AND METHODS: A total of 37 patients (7 femurs and 30 tibias), mean age 36 years, were stabilised using a mono-lateral fixator for nonunion of long bones. The mean time since injury was 8 months. Fifteen cases were infected and they received debridement and antibiotic treatment as per culture and sensitivity reports. In cases where the bone gap or shortening was >3 cm in the tibia and >5 cm in the femur, corticotomy and bone transport (bifocal procedure) was done and in the remaining cases, only compression-distraction (monofocal procedure) was done. The bone and functional results were assessed at the end of treatment according to the criteria described by Paley et al. RESULTS: Union was achieved in 34 cases (91.9%). The average time for union was 5 months. Five cases were treated with the bifocal method and 32 cases were treated with the monofocal method. The average length gain in the bifocal method was 5.7 cm, mean duration of treatment was 8.2 months and bone healing index (BHI) was 1.44 months cm(-1). In six cases, the monofocal treatment was used for limb lengthening. The average length gain was 1.9 cm, mean duration of treatment was 4.83 months and BHI was 2.5 months cm(-1). Bone grafting was required in two cases at the docking site. The bone results were excellent in 24 cases, good in nine cases, fair in one case and poor in three cases. The functional results were excellent in 27 cases, good in six cases, fair in one case and poor in three cases. The most common complication in this series was pin-tract infection (11.5%). CONCLUSIONS: A mono-lateral external fixator is an effective method for treating nonunion in the lower extremity with or without bone loss. The nonunion site can be carefully controlled with simultaneous correction of angulation and length.

EOS low-dose radiography: a reliable and accurate upright assessment of lower-limb lengths.

BACKGROUND: Children with lower-limb-length discrepancy require repeated radiographic assessment for monitoring and as a guide for management. The need for accurate assessment of length and alignment is balanced by the need to minimize radiation exposure. We compared the accuracy, reliability, and radiation dose of EOS, a novel low-dose upright biplanar radiographic imaging system, at two different settings, with that of conventional radiographs (teleoroentgenograms) and computed tomography (CT) scanograms, for the assessment of limb length. METHODS: A phantom limb in a standardized position was assessed ten times with each of four different imaging modalities (conventional radiographs, CT scanograms, EOS-Slow, EOS-Fast). A radiation dosimeter was placed on the phantom limb, on a portion closest to the radiation source for each modality, in order to measure skin-entrance radiation dose. Standardized measurements of bone lengths were made on each image by consultant orthopaedic surgeons and residents and then were assessed for accuracy and reliability. RESULTS: The mean absolute difference from the true length of the femur was significantly lower (most accurate) for the EOS-Slow (2.6 mm; 0.5%) and EOS-Fast (3.6 mm; 0.8%) protocols as compared with CT scanograms (6.3 mm; 1.3%) (p < 0.0001), and conventional radiographs (42.2 mm; 8.8%) (p < 0.0001). There was no significant difference in accuracy between the EOS-Slow and EOS-Fast protocols (p = 0.48). The mean radiation dose was significantly lower for the EOS-Fast protocol (0.68 mrad; 95% confidence interval [CI], 0.60 to 0.75 mrad) compared with the EOS-Slow protocol (13.52 mrad; 95% CI, 13.45 to 13.60 mrad) (p < 0.0001), CT scanograms (3.74 mrad; 95% CI, 3.67 to 3.82 mrad) (p < 0.0001), and conventional radiographs (29.01 mrad; 95% CI, 28.94 to 29.09 mrad) (p < 0.0001). Intraclass correlation coefficients showed excellent (>0.90) agreement for conventional radiographs, the EOS-Slow protocol, and the EOS-Fast protocol. CONCLUSIONS: Upright EOS protocols that utilize a faster speed and lower current are more accurate than CT scanograms and conventional radiographs for the assessment of length and also are associated with a significantly lower radiation exposure. In addition, the ability of this technology to obtain images while subjects are standing upright makes this the ideal modality with which to assess limb alignment in the weight-bearing position. This method has the potential to become the new standard for repeated assessment of lower-limb lengths and alignment in growing children. CLINICAL RELEVANCE: This study assesses the reliability and accuracy of a diagnostic test used for clinical decision-making.

Is pelvic obliquity related to degenerative scoliosis?

OBJECTIVE: The hypothesis of this study is that pelvic obliquity (PO) is associated with specific patterns of degenerative scoliosis. METHODS: This study was a retrospective case series of consecutive patients undergoing fusion for lumbar conditions (degenerative scoliosis or spondylolisthesis). The discrepancy in the iliac crest height, coronal L1-S1 endplate angles, distance from L1 coronal bisector to the sacral center, number of degenerative scoliosis curves, and individual curve angulations were measured. RESULTS: Limb length discrepancy was present in 87% of patients with a degenerative scoliosis. There were 116 patients with a single curve > 5° and PO > 2 cm. Of the patients with a single curve, the apex of scoliosis was opposite the high iliac crest side in 79% patients. There were 338 patients with a double curve. The apex of scoliosis was opposite the high iliac crest side in 48% of patients. CONCLUSION: There were distinct patterns of limb length discrepancy corresponding to degenerative scoliotic curve morphology. In patients with single degenerative scoliotic curves, PO most commonly appeared to counteract the scoliotic curve and result in an overall decrease in trunk shift. This occurred because the high iliac crest was observed most commonly on the convex side of the scoliotic curve. This effect was not observed in double lumbar degenerative scoliotic curves.

Cozen's phenomenon: a reminder.

A four-year-old child attended Accident and Emergency following a fall from a slide with a displaced and angulated proximal tibial metaphyseal fracture. Treatment included closed manipulation under anaesthesia and an above knee cast for seven weeks. Serial radiographs over the following few months were satisfactory demonstrating good alignment and evidence of healing. However, at four-months review new-onset genu valgum with mechanical axis deviation was noted. No evidence of spontaneous resolution was noted over the following 12 months and hence a corrective hemi-epiphysiodesis was performed. At 12-months post-operatively, there was marked clinical and radiographical improvement in alignment. Classically Cozen's phenomenon is described as the late-onset post-traumatic valgus deformity associated with proximal tibial metaphyseal fractures in children. We want to reemphasise the early recognition of children at risk of this unique complication. In addition, we wish to highlight the progression of the late-onset valgus and its subsequent management.

Linear morphea and leg length discrepancy: treatment with a leg-lengthening procedure.

A 15-year-old Colombian boy with a 10-year history of linear morphea presented to a pediatric orthopedic clinic with a leg length discrepancy. The morphea had been previously treated with methotrexate, oral and topical steroids, and topical vitamin D, but the lesion persisted, extending down the entire medial aspect of the left leg across the popliteal fossa. The patient had atrophy and growth retardation of the left leg, resulting in lower extremity bone and joint pain and a 3-cm limb length disparity at maturity. The patient preferred left tibial lengthening to improve the limb length disparity.

Leg length discrepancy in patients with slipped capital femoral epiphysis.

BACKGROUND AND PURPOSE: Leg-length discrepancy (LLD) can be a sequela of slipped capital femoral epiphysis (SCFE). We tried to identify factors that affect the development of LLD following SCFE. PATIENTS AND METHOD: We evaluated 85 patients who had been treated using percutaneous screw fixation. The average age of the patients at the time of surgery was 12 (8-16) years. The relationship of LLD and various clinical and radiographic parameters was evaluated: the degree of slip, articulotrochanteric distance (ATD), and articulotrochanteric distance difference (ATDD) (healthy side minus the side with SCFE). We assessed the relationship between ATDD and LLD based on scanogram. RESULTS: The average LLD was 1.4 (0.1-3.8) cm at 6 (2-15) years postoperatively. 48 of 85 patients had an LLD of greater than 1 cm and 10 patients had an LLD of greater than 2 cm. There was a correlation between the magnitude of LLD and the severity of the slip. There was no statistically significant correlation between LLD and the stability of the slip, age, BMI, sex, or race. There was a significant correlation between LLD and ATDD. INTERPRETATION: Patients with a high degree of slip are prone to develop clinically significant LLD. Although ATDD does not give the exact LLD, it can be used as a primary measurement, which should be supplemented with scanogram in cases of clinically significant differences in length.

Factors associated with patellofemoral pain syndrome: a systematic review.

This review systematically summarises factors associated with patellofemoral pain syndrome (PFPS). A systematic literature search was conducted. Studies including ≥20 patients with PFPS that examined ≥1 possible factor associated with PFPS were included. A meta-analysis was performed, clinical heterogeneous data were analysed descriptively. The 47 included studies examined 523 variables, eight were pooled. Pooled data showed a larger Q-angle, sulcus angle and patellar tilt angle (weighted mean differences (WMD) 2.08; 95% CI 0.64, 3.63 and 1.66; 95% CI 0.44, 2.77 and 4.34; 95% CI 1.16 to 7.52, respectively), less hip abduction strength, lower knee extension peak torque and less hip external rotation strength (WMD -3.30; 95% CI -5.60, -1.00 and -37.47; 95% CI -71.75, -3.20 and -1.43; 95% CI -2.71 to -0.16, respectively) in PFPS patients compared to controls. Foot arch height index and congruence angle were not associated with PFPS. Six out of eight pooled variables are associated with PFPS, other factors associated with PFPS were based on single studies. Further research is required.

A histomorphometric study of cellular layers after hemiepiphyseal stapling on the physeal plate in rabbits.

BACKGROUND: Epiphyseal stapling has been widely used to correct angular deformity. The mechanism, however, has not been well determined. To determine the effect of temporary hemiepiphyseal stapling on the cellular layers of the physis, a histomorphometric study was performed using immature rabbits. METHODS: Distal lateral epiphyseal stapling of the right femur was performed on 6-week-old New Zealand white rabbits. Thirty rabbits were randomly assigned to five groups, and six rabbits in each group were analyzed weekly for up to 5 weeks. RESULTS: The distal femur was deformed into the valgus, and the anatomical lateral distal femoral angle decreased with the passage of time. In the sequential histomorphometry of the operated physeal plate, the area ratio of each layer, compared to the control side, decreased every week. The total area of the physeal plate had decreased up to 60 % at the 5th week compared to the area of the 1st week, and the area of the proliferative layer decreased by the greatest amount among the three layers. CONCLUSIONS: Our findings suggest that the proliferation of chondrocytes seemed to be more suppressed by the compression of the stapling, thereby slowing the growth rate, although hypertrophy of the chondrocytes was also suppressed.

Femoral neck shortening and varus collapse after navigated fixation of intracapsular femoral neck fractures.

OBJECTIVE: Assessing femoral neck shortening (FNS) and varus collapse after internal fixation of femoral neck fractures using computerized navigation (CN). DESIGN: Retrospective cohort study. SETTINGS: Academic Level I trauma center. PATIENTS AND METHODS: Forty-one patients who had healed femoral neck fractures treated with CN between the years 2003 and 2008. Average age was 65 years (range, 14-91 years). Thirty-six patients had nondisplaced fractures and five had displaced fractures. INTERVENTION: Screws were placed using CN in an inverted triangle formation Follow-up films were digitized into a PACS system, calibrated, and analyzed using CAD software. OUTCOME MEASURES: The following parameters were recorded: abductor lever arm shortening (termed x), corresponding vertical femur shortening (termed y), and the resultant femoral neck shortening vector (z). Fifteen patients were available for clinical outcome measures by the means of SF-12 survey RESULTS: Significant FNS of the x component (greater than 5 mm) occurred in 30 of 42 (71%) patients with severe shortening (greater than 10 mm) in 25% of the patients. Significant y shortening occurred in 43% of the patients and severe shortening in 17%. Overall (z) femoral neck shortening occurred in 56% of the patients with severe shortening in 22% of patients. Varus collapse (greater than 5°) did not occur in any patient. Screw pullout (greater than 5 mm) occurred in 17 (41%) patients. Seven patients required late (greater than 6 months) arthroplasty postoperatively. FNS did not significantly correlate with fracture type, quality of reduction, age, or neck shaft angle. SF-12 results were negatively correlated with overall FNS. CONCLUSIONS: Our results show a high degree of FNS associated with the use of CN for fixation of femoral neck fractures, similar to recently published series using nonnavigated implants. However, no varus collapse occurred in our series. Our preliminary clinical data show a trend toward an adverse effect of FNS on quality-of-life measures.