Aims. Leg length discrepancy (LLD) is a common pre- and postoperative issue in total hip arthroplasty (THA) patients. The conventional technique for measuring LLD has historically been on a non-weightbearing anteroposterior pelvic radiograph; however, this does not capture many potential sources of LLD. The aim of this study was to determine if long-limb EOS radiology can provide a more reproducible and holistic measurement of LLD. Methods. In all, 93 patients who underwent a THA received a standardized preoperative EOS scan, anteroposterior (AP) radiograph, and clinical LLD assessment. Overall, 13 measurements were taken along both anatomical and functional axes and measured twice by an orthopaedic fellow and surgical planning engineer to calculate intraoperator reproducibility and correlations between measurements. Results. Strong correlations were observed for all EOS measurements (r. s. > 0.9). The strongest correlation with AP radiograph (inter-teardrop line) was observed for functional-ASIS-to-floor (functional) (r. s. = 0.57), much weaker than the correlations between EOS measurements. ASIS-to-ankle measurements exhibited a high correlation to other linear measurements and the highest ICC (r. s. = 0.97). Using anterior superior iliac spine (ASIS)-to-ankle, 33% of patients had an absolute LLD of greater than 10 mm, which was statistically different from the inter-teardrop LLD measurement (p < 0.005). Discussion. We found that the conventional measurement of LLD on AP pelvic radiograph does not correlate well with long leg measurements and may not provide a true appreciation of LLD. ASIS-to-ankle demonstrated improved detection of potential LLD than other EOS and radiograph measurements. Full length, functional imaging methods may become the new gold standard to measure LLD. Cite this article: Bone Jt Open 2022;3(12):960–968

We analysed retrospectively the risk factors leading to femoral overgrowth after flexible intramedullary nailing in 43 children (mean age 7.1 years (3.6 to 12.0)) with fractures of the shaft of the femur. We reviewed their demographic data, mechanism of injury, associated injuries, the type and location of the fractures, the nail–canal diameter (NCD) ratios and femoral overgrowth at a mean follow-up of 40.7 months (25.2 to 92.7). At that time, the children were divided into two groups, those with femoral overgrowth of < 1 cm (Group 1), and those with overgrowth of ≥ 1 cm (Group 2). The mean femoral overgrowth of all patients was 0.6 cm at final follow-up. Overgrowth of ≥ 1 cm was noted in 11 children (25.6%). The NCD ratio was significantly lower in Group 2 than in Group 1, with an odds ratio of 30.0 (p = 0.003).

We believe that a low NCD ratio is an indicator of an unstable configuration with flexible intramedullary nailing, and have identified an association between a low NCD ratio and femoral overgrowth resulting in leg-length discrepancy after flexible intramedullary nailing in paediatric femoral shaft fractures.

Cite this article: Bone Joint J 2013;95-B:254–8.

Aims. Temporary epiphysiodesis (ED) is commonly applied in children and adolescents to treat leg length discrepancies (LLDs) and tall stature. Traditional Blount staples or modern two-hole plates are used in clinical practice. However, they require accurate planning, precise surgical techniques, and attentive follow-up to achieve the desired outcome without complications. This study reports the results of ED using a novel rigid staple (RigidTack) incorporating safety, as well as technical and procedural success according to the idea, development, evaluation, assessment, long-term (IDEAL) study framework. Methods. A cohort of 56 patients, including 45 unilateral EDs for LLD and 11 bilateral EDs for tall stature, were prospectively analyzed. ED was performed with 222 rigid staples with a mean follow-up of 24.4 months (8 to 49). Patients with a predicted LLD of ≥ 2 cm at skeletal maturity were included. Mean age at surgery was 12.1 years (8 to 14). Correction and complication rates including implant-associated problems, and secondary deformities as well as perioperative parameters, were recorded (IDEAL stage 2a). These results were compared to historical cohorts treated for correction of LLD with two-hole plates or Blount staples. Results. The mean LLD was reduced from 25.2 mm (15 to 45) before surgery to 9.3 mm (6 to 25) at skeletal maturity. Implant-associated complications occurred in 4/56 treatments (7%), and secondary frontal plane deformities were detected in 5/45 legs (11%) of the LLD cohort. Including tall stature patients, the rate increased to 12/67 legs (18%). Sagittal plane deformities were observed during 1/45 LLD treatments (2%). Compared to two-hole plates and Blount staples, similar correction rates were observed in all devices. Lower rates of frontal and sagittal plane deformities were observed using rigid staples. Conclusion. Treatment of LLD using novel rigid staples appears a feasible and promising strategy. Secondary frontal and sagittal plane deformities remain a potential complication, although the rate seems to be lower in patients treated with rigid staples. Further comparative studies are needed to investigate this issue. Cite this article: Bone Joint J 2021;103-B(8):1428–1437

Aims. Internal hemipelvectomy without reconstruction of the pelvis is a viable treatment for pelvic sarcoma; however, the time it takes to return to excellent function is quite variable. Some patients require greater time and rehabilitation than others. To determine if psoas muscle recovery is associated with changes in ambulatory function, we retrospectively evaluated psoas muscle size and limb-length discrepancy (LLD) before and after treatment and their correlation with objective functional outcomes. Methods. T1-weighted MR images were evaluated at three intervals for 12 pelvic sarcoma patients following interval hemipelvectomy without reconstruction. Correlations between the measured changes and improvements in Timed Up and Go test (TUG) and gait speed outcomes were assessed both independently and using a stepwise multivariate regression model. Results. Increased ipsilesional psoas muscle size from three months postoperatively to latest follow-up was positively correlated with gait speed improvement (r = 0.66). LLD at three months postoperatively was negatively correlated with both TUG (r = -0.71) and gait speed (r = -0.61). Conclusion. This study suggests that psoas muscle strengthening and minimizing initial LLD will achieve the greatest improvements in ambulatory function. LLD and change in hip musculature remain substantial prognostic factors for achieving the best clinical outcomes after internal hemipelvectomy. Changes in psoas size were correlated with the amount of functional improvement. Several patients in this study did not return to their preoperative ipsilateral psoas size, indicating that monitoring changes in psoas size could be a beneficial rehabilitation strategy. Cite this article: Bone Joint J 2023;105-B(3):323–330

Aims. Perthes’ disease (PD) often results in femoral head deformity and leg length discrepancy (LLD). Our objective was to analyze femoral morphology in PD patients at skeletal maturity to assess where the LLD originates, and evaluate the effect of contralateral epiphysiodesis for length equalization on proximal and subtrochanteric femoral lengths. Methods. All patients treated for PD in our institution between January 2013 and June 2020 were reviewed retrospectively. Patients with unilateral PD, LLD of ≥ 5 mm, and long-leg standing radiographs at skeletal maturity were included. Total leg length, femoral and tibial length, articulotrochanteric distance (ATD), and subtrochanteric femoral length were compared between PD side and the unaffected side. Furthermore, we compared leg length measurements between patients who did and who did not have a contralateral epiphysiodesis. Results. Overall, 79 patients were included, of whom 21 underwent contralateral epiphysiodesis for leg length correction. In the complete cohort, the mean LLD was 1.8 cm (95% confidence interval (CI) 1.5 to 2.0), mean ATD difference was 1.8 cm (95% CI -2.1 to -1.9), and mean subtrochanteric difference was -0.2 cm (95% CI -0.4 to 0.1). In the epiphysiodesis group, the mean LLD before epiphysiodesis was 2.7 cm (95% CI 1.3 to 3.4) and 1.3 cm (95% CI -0.5 to 3.8) at skeletal maturity. In the nonepiphysiodesis group the mean LLD was 2.0 cm (95% CI 0.5 to 5.1; p = 0.016). The subtrochanteric region on the PD side was significantly longer at skeletal maturity in the epiphysiodesis group compared to the nonepiphysiodesis group (-1.0 cm (95% CI -2.4 to 0.6) vs 0.1 cm (95% CI -1.0 to 2.1); p < 0.001). Conclusion. This study demonstrates that LLD after PD originates from the proximal segment only. In patients who had contralateral epiphysiodesis to balance leg length, this is achieved by creating a difference in subtrochanteric length. Arthroplasty surgeons need to be aware that shortening of the proximal femur segment in PD patients may be misleading, as the ipsilateral subtrochanteric length in these patients can be longer. Therefore, we strongly advise long-leg standing films for THA planning in PD patients in order to avoid inadvertently lengthening the limb. Cite this article: Bone Joint J 2021;103-B(11):1736–1741

The results of total hip arthroplasty (THA) revisions to correct leg length discrepancy (LLD) are not clear, with only two former limited series (< 25 patients). Therefore, we conducted a retrospective study of THA revisions for LLD to determine: 1) the change in LLD, 2) the function outcomes and whether obtaining equal leg lengths influenced function, 3) the complication and survival rates. This multicenter study included 57 patients: 42 THA revisions for limb shortening and 15 revisions for limb lengthening. LLD was measured on conventional radiographs and EOS. The Oxford-12 and FJS outcome scores were collected and the number of patients achieving the Oxford-12 MCID. The revisions were carried out a mean of 2.8 years after the index THA. The median LLD decreased from 7.5 mm (IQR: [5;12]) to 1 mm (IQR: [0.5;2.5]) at follow-up (p=0.0002). Overall, 55 of 57 patients (96%) had < 5 mm LLD at follow-up and 12 patients (21%) had equal leg lengths. The complication rate was 25%: 12 mechanical complications (8 periprosthetic femoral fractures, 2 stem loosening and 1 cup loosening, 1 dislocation) and 1 periprosthetic infection. The patient satisfaction was high with a median FJS of 79.2/100 and 77% of patients reached the Oxford-12 MCID. Lengthening procedures had significantly worst function than shortening (38% vs 91% of patients achieving the Oxford-12 MCID (p=0.0004)). Survivorship was 85% (95% CI: 77.9 – 92.5) at 2 years and 77% (95% CI: 66.3 – 87.1) at 4.6 years when using re-revision for any reason as the endpoint. When LLD after THA does not respond to conservative management, revision THA should be considered. Although revision THA for LLD improved medium-term functional outcomes with a high patient satisfaction rate, especially for shortening procedures, the complication rate was high, particularly related to periprosthetic femoral fracture

Introduction. Coronal malalignment and leg length discrepancies (LLD) are frequently associated. Temporary hemiepiphysiodesis (tHED) is commonly employed for the correction of limb malalignment in skeletally immature patients. For treatment of LLD greater than 2 cm, lengthening with intramedullary legnthening nails is a safe and reliable technique. However, the combined application of these approaches in skeletally immature patients has not yet been investigated. Materials & Methods. Retrospective radiological and clinical analysis of 25 patients (14 females, 11 males) who underwent intramedullary femoral lengthening with an antegrade PRECICE® lengthening nail as well as tHED of the distal femur and / or proximal tibia between 2014 and 2019. tHED was conducted by implantation of flexible staples (FlexTack™) either prior (n = 11), simultaneously (n = 10), or subsequently (n = 4) to femoral lengthening. The mean follow-up period was 3.7 years (±1.4). Results. The median initial LLD was 39.0 mm (35.0–45.0). 21 patients (84%) presented valgus and 4 (16%) showed varus malalignment. Leg length equalization was achieved in 13 patients at skeletal maturity (62%). The median LLD of patients with a residual LLD > 10 mm was 15.5 mm (12.8–21.8). Limb realignment was obtained in nine of seventeen skeletally mature patients (53%) in the valgus group, and in one of four patients (25%) in the varus group. Conclusions. The combination of antegrade femoral lengthening and tHED can efficiently correct LLD and coronal limb malalignment in skeletally immature patients. Nevertheless, achieving limb length equalization and realignment may render difficult in cases of severe LLD and angular deformity. Furthermore, the reported techniques ought to be thoroughly planned and executed and require regular clinical and radiological examinations until skeletal maturity to avoid - or timely detect and manage - adverse events such as overcorrection and rebound of deformity

Aims. The purpose of this study was to examine whether leg-length discrepancy (LLD) following unilateral total hip arthroplasty (THA) affects the incidence of contralateral head collapse and subsequent THA in patients with bilateral osteonecrosis, and to determine factors associated with subsequent collapse. Patients and Methods. We identified 121 patients with bilateral non-traumatic osteonecrosis who underwent THA between 2003 and 2011 to treat a symptomatic hip, and who also exhibited medium-to-large lesions (necrotic area ≥ 30%) in an otherwise asymptomatic non-operated hip. Of the 121 patients, 71 were male (59%) and 50 were female (41%), with a mean age of 51 years (19 to 71) at the time of initial THA. All patients were followed for at least five years and were assessed according to the presence of a LLD (non-LLD vs LLD group), as well as the LLD type (longer non-operated side vs shorter non-operated side group). Results. Overall, 68 hips (56%) became painful and progressed to collapse at a mean of 2.6 years (0.2 to 13.8), resulting in 59 THAs (49%). The five-year collapse-free survival rate for the non-LLD group was 59% (95% confidence interval (CI) 46.8 to 71.8) compared with 45% (95% CI 32.9 to 57.5) for the LLD group (p = 0.036), and 66% (95% CI 55.2 to 77.2) for the longer non-operated side group compared with 32% (95% CI 19.1 to 44.9) for the shorter non-operated side group (p < 0.001). Multivariate regression analyses found that large lesions had a higher risk of collapse than medium-size lesions (odds ratio (OR) 4.19, 95% confidence interval (CI) 1.69 to 10.38; p = 0.002). Meanwhile, patients with a LLD < 3 mm (OR 0.20, 95% CI 0.08 to 0.52; p = 0.001) or a longer non-operated leg (OR 0.11, 95% CI 0.04 to 0.28; p < 0.001) after THA were less likely to experience a subsequent collapse. Conclusion. We found that LLD may be a modifiable risk factor for femoral head collapse. Minimizing LLD and particularly avoiding a shorter non-operated limb after THA may lead to a lower risk of collapse of the asymptomatic hip in patients with bilateral non-traumatic osteonecrosis. Cite this article: Bone Joint J 2019;101-B:303–310

Introduction. Leg length discrepancy (LLD) is a common sequalae of limb reconstruction procedures. The subsequent biomechanical compensation can be directly linked to degenerative arthritis, lower back pain, scoliosis and functional impairment. It becomes particularly problematic when >2cm, established as a clinical standard. This two-arm experimental study assesses how reliable an iPhone application is in the measurement of LLD at different distances in control and LLD patients. Materials and Methods. 42 participants were included in the study, divided evenly into 21 control and 21 LLD patients. A standardised measurement technique was used to obtain TMM and iPhone application measurements, taken at a distance of 0.25m, 0.50m and 0.75m. Results. The mean discrepancy of iPhone-based measurements in the control group was 1.57cm, 1.59cm and 2.19cm at 0.25m, 0.50m and 0.75m respectively. This compares to measurements in the LLD cohort with a mean discrepancy of 1.71cm, 1.85cm and 2.19cm. The overall mean discrepancy of iPhone data was 1.78cm in the control cohort compared to 1.92cm in the LLD cohort. Conclusions. Results suggest that the iPhone application can be used to identify clinically significant leg length discrepancies. At 0.75 metres anomalous results become more prevalent and the accuracy of the application appears to decline. The results also suggest the application is slightly more accurate in the control group, nevertheless, in distances up to 0.50 metres the mean discrepancy sits within the 2cm standard of clinically significant LLD

Abstract. Congenital posteromedial bowing of tibia (CPMBT) progresses with decreasing deformity and increasing shortening. Lengthening in CPMBT has not been studied extensively. Our series compares duration and complications of lengthening in younger vs older children. Methods. 28 tibial lengthenings (23 patients) by a single surgeon, divided into two equal groups of 14 segments: group-A ≤ 5 years, Group-B > 5 years. Lengthening was done in all with external fixators. We measured preoperative (bo) and postoperative (po) deformities, initial limb length discrepancy (LLD), LLD at maturity (LLDm), % LLD, amount of lengthening (AmtL) and %L, external fixator duration (EFD) and external fixator index (EFI). We graded complications by Lascombes' criteria, results by ASAMI Bone score. Results. Mean age was 8.8 ± 7.1 years. Follow-up was 7.9 years. Group-A had significantly greater preoperative deformities. LLD was similar in both. Expected LLD at maturity (LLDM) using the multiplier method was greater than previously reported (group-A: 4.4 – 9.5 cm; group-B: 2.5 – 9.7 cm).%L was 24% in group-A and 15.7% in group-B (p=0.002). EFD and EFI were lesser in group-A than group-B. Lascombes' triple contract was fulfilled in 11/14 lengthenings in group-A vs. 3/14 in group-B. ASAMI bone score was good and excellent in both groups. Conclusions. In our large series of CPMBT lenghtenings, we found younger children presenting with large deformities and LLDm could be safely lengthened with lesser EFD and complications than older children

Aims. Guided growth using eight-plates is commonly used for correction of angular limb deformities in growing children. The principle is of tethering at the physeal periphery while enabling growth in the rest of the physis. The method is also applied for epiphysiodesis to correct limb-length discrepancy (LLD). Concerns have been raised regarding the potential of this method to create an epiphyseal deformity. However, this has not been investigated. The purpose of this study was to detect and quantify the occurrence of deformities in the proximal tibial epiphysis following treatment with eight-plates. Patients and Methods. A retrospective study was performed including 42 children at a mean age of 10.8 years (3.7 to 15.7) undergoing eight-plate insertion in the proximal tibia for correction of coronal plane deformities or LLD between 2007 and 2015. A total of 64 plates were inserted; 48 plates (34 patients) were inserted to correct angular deformities and 16 plates (8 patients) for LLD. Medical records, Picture Archive and Communication System images, and conventional radiographs were reviewed. Measurements included interscrew angle, lateral and medial plateau slope angles measured between the plateau surface and the line between the ends of the physis, and tibial plateau roof angle defined as 180° minus the sum of both plateau angles. Measurements were compared between radiographs performed adjacent to surgery and those at latest follow-up, and between operated and non-operated plateaus. Statistical analysis was performed using BMDP Statistical Software. Results. Slope angle increased in 31 (49.2%) of operated epiphyses by a mean of 5° (1° to 23°) compared with 29 (31.9%) in non-operated epiphyses (p = 0.043). Roof angle decreased in 29 (46.0%) of operated tibias and in 25 (27.5%) of non-operated ones by a mean of 5° (1° to 18°) (p = 0.028). Slope angle change frequency was similar in patients with LLD, varus and valgus correction (p = 0.37) but roof angle changes were slightly more frequent in LLD (p = 0.059) and correlated with the change in inter screw angles (r = 0.74, p = 0.001). Conclusion. The use of eight-plates in the proximal tibia for deformity correction and limb-length equalization causes a change in the bony morphology of the tibial plateau in a significant number of patients and the effect is more pronounced in the correction of LLD. Cite this article: Bone Joint J 2018;100-B:1112–16

We compared the accuracy of the growth remaining method of assessing leg-length discrepancy (LLD) with the straight-line graph method, the multiplier method and their variants. We retrospectively reviewed the records of 44 patients treated by percutaneous epiphysiodesis for LLD. All were followed up until maturity. We used the modified Green–Anderson growth-remaining method (Method 1) to plan the timing of epiphysiodesis. Then we presumed that the other four methods described below were used pre-operatively for calculating the timing of epiphysiodesis. We then assumed that these four methods were used pre-operatively. Method 2 was the original Green–Anderson growth-remaining method; Method 3, Paley’s multiplier method using bone age; Method 4, Paley’s multiplier method using chronological age; and Method 5, Moseley’s straight-line graph method. We compared ‘Expected LLD at maturity with surgery’ with ‘Final LLD at maturity with surgery’ for each method. Statistical analysis revealed that ‘Expected LLD at maturity with surgery’ was significantly different from ‘Final LLD at maturity with surgery’. Method 2 was the most accurate. There was a significant correlation between ‘Expected LLD at maturity with surgery’ and ‘Final LLD at maturity with surgery’, the greatest correlation being with Method 2. Generally all the methods generated an overcorrected value. No method generates the precise ‘Expected LLD at maturity with surgery’. It is essential that an analysis of the pattern of growth is taken into account when predicting final LLD. As many additional data as possible are required. Cite this article: Bone Joint J 2013;95-B:993–1000

Introduction. Legg-Calvé-Perthes disease (LCPD) often results in femoral head deformity and leg length discrepancy (LLD). Objective of this study was to analyse femoral morphology in LCPD patients at skeletal maturity to assess where the LLD originates, and evaluate the effect of contralateral epiphysiodesis for length equalisation on proximal and subtrochanteric femoral lengths. Materials and Methods. All patients treated for LCPD in our institution between January 2013 and June 2020 were retrospectively reviewed. Patients with unilateral LCPD, LLD of ≥5mm and long leg standing radiographs at skeletal maturity were included. Total leg length, femoral and tibial length, articulotrochanteric distance (ATD) and subtrochanteric femoral length were compared between LCPD side and unaffected side. Furthermore, we compared leg length measurements between patients who did and who did not have a contralateral epiphysiodesis. Results. 79 patients were included, 21/79 underwent contralateral epiphysiodesis for leg length correction. In the complete cohort the average LLD was 1.8cm (95% CI 1.5 – 2.0), average ATD difference was 1.8cm (95% CI −2.1 – −1.9) and average subtrochanteric difference was −0.2cm (95% CI −0.4 – 0.1). In the epiphysiodesis group the average LLD before epiphysiodesis was 2.7 (1.3 – 3.4) cm and 1.3 (−0.5 – 3.8) cm at skeletal maturity. In the non-epiphysiodesis group the average LLD was 2.0 (0.5 – 5.1), p=0.016. The subtrochanteric region on the LCPD side was significantly longer at skeletal maturity in the epiphysiodesis group compared to the non-epiphysiodesis group: −1.0 (−2.4 – 0.6) versus 0.1 (−1.0 – 2.1), p<0.001. Conclusions. This study concludes that LLD after LCPD originates from the proximal segment only. In patients who had had a contralateral epiphysiodesis, the subtrochanteric femoral region was significantly longer on the LCPD side. These anatomical changes need to be considered by paediatric surgeons when advising leg length equalisation procedures, and by arthroplasty surgeons when LCPD patients present for hip arthroplasty

Introduction. Femoral-shortening osteotomy for the treatment of leg length discrepancy is demanding technique. Many surgical technique and orthopaedic devises have been suggested to perform this procedure. Herein, we describe modified femoral shortening osteotomy over a nail, using a percutaneous multiple drill-hole osteotomy technique. Materials and Methods. We operated on six patients with LLD. Mean femoral shortening was 4.2 cm. Osteotomy was performed using a multiple drill-hole technique, and bone was stabilized using an intramedullary nail. Post-operative clinical and radiological data were reported. Results. Shortening was achieved, with a final LLD of < 1 cm in all patients. All patients considered the lengths of the lower limbs to be equal. No special surgical skills or instrumentation were needed. Intraoperative and post-operative complications were not recorded. Conclusions. Percutaneous femoral-shortening osteotomy over a nail using multiple drill-hole osteotomy technique was effective and safe in treating LLD

Aims. There is no consensus about the best method of achieving equal leg lengths at total hip arthroplasty (THA) in patients with Crowe type-IV developmental dysplasia of the hip (DDH). We reviewed our experience of a consecutive series of patients who underwent THA for this indication. Patients and Methods. We retrospectively reviewed 78 patients (86 THAs) with Crowe type-IV DDH, including 64 women and 14 men, with a minimum follow-up of two years. The mean age at the time of surgery was 52.2 years (34 to 82). We subdivided Crowe type-IV DDH into two major types according to the number of dislocated hips, and further categorised them into three groups according to the occurrence of pelvic obliquity or spinal curvature. Leg length discrepancy (LLD) and functional scores were analysed. Results. Type-I included 53 patients with unilateral dislocation, in which 25 (category A) had no pelvic obliquity or spinal deformity, 19 (category B) had pelvic obliquity with a compensated spinal curvature and nine (category C) had pelvic obliquity and decompensated spinal degenerative changes. Type-II included 25 patients with one dislocated and one dysplastic hip, in which there were eight of category A, 15 of category B and two of category C. Pre-operatively, there were significant differences between the anatomical and functional LLD in type-IB (p = 0.005) and -IC (p < 0.001), but not in type-IA, -IIA or -IIB. Post-operatively, bony LLD increased significantly in types-IB, -IC and -IIB, whereas functional LLD decreased significantly in each type except for IIA. The mean functional LLD decreased from 30.7 mm (standard deviation (. sd. ) 18.5) pre-operatively to 6.2 mm (. sd. 4.4) post-operatively and the mean anatomical LLD improved from 35.8 mm (. sd. 19.7) pre-operatively to 12.4 mm (. sd. 8.3) post-operatively. Conclusion. Pelvic and spinal changes are common in patients with Crowe type-IV DDH and need to be taken into consideration when planning THA, in order to obtain equal leg lengths post-operatively. The principal subdivisions of Crowe type-IV DDH which we describe proved effective in achieving equal leg lengths and satisfactory outcomes. Cite this article: Bone Joint J 2017;99-B:872–9

Introduction. Congenital posteromedial bowing of tibia (CPMBT) is characterized by a decreasing deformity and an increasing limb shortening. Our series compares the duration and complications of lengthening in younger vs older children. Materials and Methods. We studied 28 tibial lengthenings in 23 patients, divided into two equal groups of 14 segments: group-A ≤5 years (preschool) and Group-B >5 years. We measured preoperative (bo) and postoperative (po) sagittal, coronal, and oblique plane deformities, limb length discrepancy (LLD), amount of lengthening (AmtL), percentage lengthening (%L), external fixator duration (EFD) and external fixator index (EFI). Complications were graded by Lascombes’ criteria, results by ASAMI Bone score. Results. Mean age= 8.8 ± 7.1 years; mean follow-up= 7.9 years. Group-A had significantly greater bo-sagittal, coronal, and oblique plane deformities. LLD (3.4 cm in group-A vs. 4.1 cm in group-B) was similar in both. LLD at maturity (LLD. M. ) by multiplier method ranged 4.4–9.5 cm in group-A and 2.5–9.7 cm in group-B. Though AmtL (3.5 cm and 4.1 cm) was similar in both, %L was 24% in group-A and 15.7% in group-B (p=0.002). EFD (116.6 days) and EFI (33.7 days/cm) were lesser in group-A vs group-B (200.3 days, p=0.001; 50.2 days/cm, p=0.01). Lascombes’ criteria were fulfilled in 11/14 lengthenings in group-A vs. 3/14 in group-B. ASAMI bone score was good and excellent in both groups (p=0.44). Conclusions. Younger children with large deformities and LLD. M. could be safely lengthened with lesser external fixator duration and complications than in older children

Summary. The mathematical model has proven to be highly accurate in measuring leg length before and after surgery to determine how leg length effects hip joint mechanics. Introduction. Leg length discrepancy (LLD) has been proven to be one of the most concerning problems associated with total hip arthroplasty (THA). Long-term follow-up studies have documented the presence of LLD having direct correlation with patient dissatisfaction, dislocation, back pain, and early complications. Several researchers sought to minimize limb length discrepancy based on pre-operative radiological templating or intra-operative measurements. While often being a common occurrence in clinical practice to compensate for LLD intra-operatively, the center of rotation of the hip joint has often changes unintentionally due to excessive reaming. Therefore, the clinical importance of LLD is still difficult to solve and remains a concern for clinicians. Objective. The objective of this study is two-fold: (1) use a validated forward-solution hip model to theoretically analyze the effects of LLD, gaining better understanding of mechanisms leading to early complication of THA and poor patient satisfaction and (2) to investigate the effect of the altered center of rotation of the hip joint regardless LLD compensation. Methods. The theoretical mathematical model used in this study has been previously validated using fluoroscopic results from existing implant designs and telemetric devices. The model can be used to theoretically investigate various surgical alignments, approaches, and procedures. In this study, we analyzed LLD and the effects of the altered center of rotation regardless of LLD compensation surgeons made. The simulations were conducted in both swing and stance phase of gait. Results. During swing phase, leg shortening lead to loosening of the hip capsular ligaments and subsequently, variable kinematic patterns. The momentum of the lower leg increased to levels where the ligaments could not properly constrain the hip leading to the femoral head sliding from within the acetabular cup (Figure 1). This piston motion led to decreased contact area and increased contact stress within the cup. Leg lengthening did not yield femoral head sliding but increased joint tension and contact stress. A tight hip may be an influential factor leading to back pain and poor patient satisfaction. During stance phase, leg shortening caused femoral head sliding leading to decreased contact area and an increase in contact stress. Leg lengthening caused an increase in capsular ligaments tension leading to higher stress in the hip joint (Figure 2). Interestingly, when the acetabular cup was superiorized and the surgeon compensated for LLD, thus matching the pre-operative leg length by increasing the neck length of the femoral implant, the contact forces and stresses were marginally increased at heel strike (Figure 3). Conclusion and Discussion. Altering the leg length during surgery can lead to higher contact forces and contact stresses due to tightening the hip joint or increasing likelihood of hip joint separation. Leg shortening often lead to higher stress within the joint. Further assessment must be conducted to develop tools that surgeons can use to ensure post-operative leg length is similar to the pre-operative condition. For any figures or tables, please contact authors directly

Introduction. Management of deformity involving limb length discrepancy (LLD) using intramedullary devices offers significant benefits to both patients and clinicians over traditional external fixation. Following the withdrawal of the PRECICE nail, the Fitbone became the primary implant available for intramedullary lengthening and deformity correction within our service. This consecutive series illustrates the advantages and complications associated with the use of this device, and describes a novel technique modification for antegrade intramedullary lengthening nails. Materials & Methods. A retrospective cohort review was performed of patient outcomes after treatment with the Fitbone nail at two tertiary referral limb reconstruction services (one adult, one paediatric) between January 2021 to December 2023. Aetiology, indications, initial and final LLD, use of concomitant rail assisted deformity correction (ORDER), removal time and healing index were assessed. Complications of treatment were evaluated and described in detail, alongside technique modifications to reduce the rate of these complications. Results. 21 nails (18 femoral, 2 tibial, 1 humeral) were inserted in 6 adult and 13 paediatric patients. Post-traumatic and congenital/developmental LLD were the most common indications for surgery in the adult and paediatric cohorts respectively. ORDER was employed in 11 cases (9 femurs and 2 tibias). Treatment goals were achieved in all but one case. Complications included superficial infection, locking bolt migration, periprosthetic fracture and component failure. Seven patients required unplanned returns to theatre. Conclusions. The Fitbone nail is an established option for intramedullary limb lengthening, however its use in the UK has been relatively limited compared to the PRECICE until 2021. Our data helps to define its place for limb lengthening and complex deformity correction in both adult and paediatric patients, including in humeral lengthening and retrograde femoral insertion across an open physis. We have identified important potential risks and novel techniques to simplify surgery and avoid complications

Aims. Adult patients with history of childhood infection pose a surgical challenge for total hip arthroplasty (THA) due to distorted bony anatomy, soft-tissue contractures, risk of reinfection, and relatively younger age. Therefore, the purpose of the present study was to determine clinical outcome, reinfection rate, and complications in patients with septic sequelae after THA. Methods. A retrospective analysis was conducted of 91 cementless THAs (57 male and 34 female) performed between 2008 and 2017 in patients who had history of hip infection during childhood. Clinical outcome was measured using Harris Hip Score (HHS) and Modified Merle d’Aubigne and Postel (MAP) score, and quality of life (QOL) using 12-Item Short Form Health Survey Questionnaire (SF-12) components: Physical Component Score (PCS) and Mental Component Score (MCS); limb length discrepancy (LLD) and radiological assessment of the prosthesis was performed at the latest follow-up. Reinfection and revision surgery after THA for any reason was documented. Results. There was significant improvement in HHS, Modified Merle d’Aubigne Postel hip score, and QOL index SF 12-PCS and MCS (p < 0.001) and there was no case of reinfection reported during the follow-up. The minimum follow-up for the study was three years with a mean of 6.5 (SD 2.3; 3 to 12). LLD decreased from a mean of 3.3 cm (SD 1) to 0.9 cm (SD 0.8) during follow-up. One patient required revision surgery for femoral component loosening. Kaplan-Meier survival analysis estimated revision-free survivorship of 100% at the end of five years and 96.9% (95% confidence interval 79.8 to 99.6) at the end of ten years. Conclusion. We found that cementless THA results in good to excellent functional outcomes in patients with a prior history of childhood infection. There is an exceedingly low rate of risk of reinfection in these patients, even though complications are not uncommon. Cite this article: Bone Jt Open 2022;3(4):314–320

Introduction. One of the more common complaints from patients in their post-operative total knee arthroplasty (TKA) is the perceived feeling of the operative leg feeling longer than the non-operative leg. Studies have shown that the leg length discrepancies may occur in up to 80% of patients following unilateral TKA patients. The purpose of this study was to determine the incidence of leg length discrepancy (LLD) after primary TKA as well as determine the correlation between deformity and incidence of LLD. Methods. We retrospectively reviewed 1108 patients who underwent a primary unilateral TKA at a single institution. 97 patients were excluded for lack of imaging, prior total hip replacement or body mass index greater than 40 kg/m2. Hip to ankle biplanar radiographs were obtained pre-operative and 6 weeks postoperatively for all patients. Two independent observers measures leg length, femur length, tibia length, overall alignment and deformity present for all radiographs. Results. 1,101 patients were included. Mean overall lengthening was 3.4 mm [Range −21 to 22.8mm; SD 7.4] with 81% of limbs lengthened. In our cohort, 9% of patients had LLD greater than 10 mm and 43% of patients had LLD of more than 5mm after TKA. Post-operative radiographic LLD was associated with increased pre-operative LLD (P<.001) and with female gender (p=0.03). Patients with pre-operative valgus deformity were more likely to have an increased lengthening of greater than 5mm compared to patients with varus deformity (OR:1.66). Conclusion. 43% of patients will have a LLD >5mm following correction of deformity and ligament balances in knee replacement surgery. Surgeons should be aware and this should be reviewed with patients as part of their expectations of surgery. For figures, tables, or references, please contact authors directly