Age-related differences in interlimb coordination during typical gait: An observational study

BackgroundArm movements during gait are known to alter with increasing age during the slow maturation phase (>3years). It is unclear whether coordination between the arms and legs (i.e. interlimb coordination), which is a measure of gait quality, shows a similar pattern.Research Questionto investigate age-related differences in interlimb coordination during gait in typically developing children and adults.MethodsIn this observational study, 98 typically developing participants were divided into five age-groups: preschool children (G1; 2.9–5.9 years[n = 18]), children (G2; 6.0–9.9 years[n = 22]), pubertal children (G3; 10.0–13.9 years[n = 26]), adolescents (G4; 14.0–18.9 years[n = 14]) and adults (G5; 19.0–35.2 years[n = 18]). Participants walked barefoot at a self-selected walking speed along a 10-m walkway during three-dimensional total-body gait analysis. To examine interlimb coordination, mean continuous relative phase over the gait cycle (MRP) and its variability (sdMRP) were calculated for each combination of limb pairs in the sagittal plane.ResultsMRP increased towards more anti-phase coordination with increasing age in following limb pair combinations: left arm-right arm (median[interquartile range]; G1: 152.0°[126.6;160.7°]-G5: 171.5°[170.0;175.3°]), left arm-left leg (G1: 155.0°[131.3;167.6°]-G5: 170.8°[165.3;173.5°]) and right arm-right leg (G1: 155.7°[135.5;166.0°]-G5: 170.0°[166.4;173.5°]). MRP decreased towards more in-phase coordination from G1 to G5 in left arm-right leg (G1: 24.4°[15.3;45.8°]-G5: 10.5°[6.1;15.6°]) and right arm-left leg (G1: 25.0°[13.7;41.1°]-G5: 9.7°[5.2;16.8°]). sdMRP decreased from G1 to G5 for all limb pair combinations.SignificanceInterlimb coordination altered with increasing age. First, coordination between the legs and right arm-left leg appeared mature in G1 (aged 2.9−5.9 years). Next, coordination between the ipsilateral limbs seemed mature at 9.9 years, followed by a mature coordination between left arm-right leg at 13.9years. Coordination between the two arms showed ongoing differences until adulthood. These data provide an age-related framework and normative dataset to distinguish age-related differences from pathology in children with neuromotor disorders in clinical practice.     

Tibiofemoral kinematic analysis of knee flexion for a medial pivot knee

The performance of total knee arthroplasty in deeply flexed postures is of increasing concern as the procedure is performed on younger, more physically active and more culturally diverse populations. Several implant design factors, including tibiofemoral conformity, tibial slope and posterior condylar geometry have been shown directly to affect deep flexion performance. The goal of this study was to evaluate the kinematics of a fixed-bearing, asymmetric, medial rotation arthroplasty design in moderate and deep flexion. Thirteen study participants (15 knees) with a medial rotation knee arthroplasty were observed performing a weight-bearing lunge activity to maximum comfortable flexion and kneeling on a padded bench from 90° to maximum comfortable flexion using lateral fluoroscopy. Subjects averaged 74 years of age and nine were female. At maximum weight-bearing flexion, the knees exhibited 115° of implant flexion (102°–125°) and 7° (−3° to 12°) of tibial internal rotation. The medial and lateral condylar translated posteriorly by 2 and 5 mm, respectively. At maximum kneeling flexion, the knees exhibited 119° of implant flexion (101°–139°) and 5° (−2° to 14°) of tibial internal rotation. The lateral condyle translated posteriorly by 11 mm. The medial rotation knee exhibited motion patterns similar to those observed in the normal knee, but less tibial rotation. The medially conforming articulation beneficially controls femoral AP position in deep flexion, in patients who require such motion as part of their lifestyle. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Measurement and comparison of the difference in normal medial and lateral knee joint opening

This paper reports the amount of medial and lateral knee joint opening in the general population. Knee joint lateral and medial opening at 20° knee flexion was quantified on manual varus and valgus stress test, respectively, with custom made device. One hundred men and women between the ages of 20–60 years were evaluated for their joint openings. Patients with previous knee surgeries or chronic knee pains were excluded from the study. Measurements were done twice by two different orthopedic surgeons who were blinded from each other. The mean age of the study group was 39 years (range 20–60 years) and 43 years for women (range 20–60 years) and 34 years for men (range 20–60). The mean lateral and medial knee joint space opening was 7.0° (range 3–9°) and 4.1° (range 2–7°), respectively, in the overall population; in the male population, it was 6.7° (range 3–9°) and 3.9° (range 2–7°), respectively, and in the female population, it was 7.2° (range 3–9°) and 4.3° (range 3–7°), respectively. Conversion to displacement in millimetres, the overall mean lateral and medial joint displacement was 9.3 mm (range 5.1–13.6 mm) and 4.8 mm (range 3.5–10.7 mm), respectively; for males, it was 9.1 (range 5.1–11.9 mm) and 4.6 mm (range 3.5–7.9 mm), respectively, for females, it was 9.8 mm (range 7.2–13.6 mm) and 4.9 mm (range 3.7–10.7 mm), respectively. The prevalence of the overall population that exceeds 6 mm or more lateral joint space opening was 91% (male 90% and female 92%) and medial joint space was 8% (male 4% and female 12%). Statistically, significant differences were seen between medial and lateral opening in male, female and the overall population (p<0.001). The female population exhibited wider opening in both medial and lateral joint opening than the male population (p<0.05). The interexaminer reliability showed no significant difference (p>0.05). More than 91% of the Korean population showed wide lateral joint space opening in the bilateral knee. However, none complained of functional instability or symptoms except for non-pathologic laxity detected by the physician. We strongly recommend bilateral comparison of the knee that has wide lateral joint opening.     

Tibial rotation outcomes following hamstring lengthening as part of single event multilevel surgery in children with cerebral palsy

BackgroundHamstring lengthening remains the most common surgical procedure in the treatment of crouch gait for children with cerebral palsy (CP). While sagittal plane knee kinematics have been shown to improve post-surgery, the effects on transverse plane kinematics have not been reported. Given the differing actions of the medial and lateral hamstring muscles there is potential for change in tibial rotation post hamstring lengthening.Research questionWhat is the effect of medial only versus combined medial and lateral hamstring lengthening on tibial rotation during gait in children with CP?MethodsA retrospective analysis of children with a diagnosis of CP who underwent a hamstring lengthening procedure. These children were divided into 2 groups: G1 (n = 18) had isolated medial hamstring lengthening while G2 (n = 30) had combined medial and lateral hamstring lengthening. A matched non-surgical control group (n = 15) was also included. Kinematic data were analysed pre and post-operatively. Pre-operative to post-operative outcomes for G1 and G2, a comparison at baseline for both groups and the difference in outcomes between the groups were analysed. Baseline to follow-up outcomes for the control group were also analysed.ResultsExternal tibial rotation increased significantly within groups (G1: −10°, p < 0.01; G2: −11°, p < 0.001, control: −7.7, p < 0.01), with no significant difference in the change between the intervention groups. Foot progression angles became more external in both intervention groups (G1: −15°, p < 0.001; G2: −15°, p < 0.0001) and did not change in the control group.SignificanceResults demonstrated similar increases in external tibial rotation, regardless of whether an isolated medial or combined medial and lateral surgery was performed. The control group demonstrated a similar change in external tibial rotation suggesting that hamstring lengthening surgery does not contribute to increased external tibial rotation in children with CP compared to what would be expected due to natural progression.     

Open wedge tibial osteotomies influence on axial rotation and tibial slope

Inaccurate coronal plane and inadvertent sagittal plane realignment is a common problem after high tibial osteotomies (HTO). While the effects of an HTO on the coronal have been studied extensively, the influence on axial rotation has not been described in detail. The current study examines the effect of HTO on tibial rotation in the axial plane as determined by computed tomography. We hypothesized that high tibial osteotomies have an effect on tibial rotation in the axial plane and that depending on the predefined osteosynthetic implant used, a corresponding change in the tibial slope would occur. HTOs with a tapered 12.5 mm Puddu plate were performed on 13 limbs under computer-navigated control. All limbs were CT scanned before and after the HTO. Using specific software, the CT data was converted into 3D computer models and the following parameters compared: (a) varus-valgus leg alignment; (b) tibial axial rotation; (c) tibial slope (including determination of lateral and medial tibial slope, (d) leg length including determination of the tibial length. Results revealed: (a) a varus-valgus alignment increase of 11 ± 4.7° (P < 0.005); (b) an axial tibial rotation of 2.7 ± 6.3° (P < 0.075) occurred with external rotation in 10 out of 13 limbs (12° max external; 9.5° max internal); (c) tibial slope revealed differences of 4.2 ± 5.9° (P < 0.025); (d) the tibial length increased after HTO by 7.1 ± 3.7 mm (P < 0.005), while there was no significant change in overall leg length. In summary, tibial rotation does occur in high tibial osteotomies with though the degree of external rotation in this study tended not to be statiscally significant. Tapered implants do not guarantee maintenance of a steady tibial slope, while tibial length changes significantly when HTOs are performed. The combined use of CT and 3D software measurement techniques is reproducible and can be used without any further invasive fixation devices.     

Investigation of vertebral "end plate sclerosis"

Objective: To evaluate the association between vertebral ”end plate sclerosis” and neck pain. Design: A retrospective study was carried out of lateral cervical spine radiographs with a Picture Archive and Communication System (PACS). Patients: Two hundred patients’ files were randomly assessed, comprising four equal groups, A to D. The mean ages of the patients were 62±7.4 years, 61±7.5 years, 40±5.6 years and 23±5.6 years respectively. In group A, all patients had symptoms of neck pain and a radiographic diagnosis of ”end plate sclerosis” of the cervical spine. In groups B to D, asymptomatic patients were recruited and their age groups were 50–69, 30–49 and 10–29 years respectively. Using the PACS, the radiographic density and the sagittal diameter, thickness and area of the end plates at the C5 level were measured. Results and conclusions: No significant differences were found in the radiographic density of the end plates either between the symptomatic and asymptomatic groups (groups A and B), or between different age groups (groups B, C and D). A significant increase in end plate area and thickness was found, however, in both group B (P<0.005) and group C (P<0.01) in comparison with group D. This indicates that the extent of end plate sclerosis increases with age. Our results suggest that the radiographic density of cervical vertebral end plates correlates neither with neck pain nor with increasing age. The radiological sign of ”end plate sclerosis” may be over-reported, further limiting its value in the assessment of patients with cervical spondylosis. Received: 31 August 1999 Revision requested: 5 November 1999 Revision received: 19 March 2001 Accepted: 27 March 2001     

Stress fractures of the lateral metatarsal bones in metatarsus adductus foot deformity: a previously unrecognized association

Objective. To document a distinctive pattern of stress fractures in the lateral metatarsal bones of patients with metatarsus adductus foot deformity. Design and patients. Conventional radiographs and available medical records were reviewed in 11 patients (6 women, 5 men; ages 25–61 years) with stress fractures of the lateral (fourth or fifth) metatarsal bones and metatarsus adductus. Evaluation included the number and location of fracture(s), forefoot adduction angle, and qualitative assessment of bone mineral density. Conditions that might predispose patients to metatarsal fractures, including direct trauma, osteoporosis, and neuropathic osteoarthropathy were also recorded. Results. A total of 22 stress fractures were demonstrated, 17 of which involved the lateral metatarsals. A solitary fracture was present in six patients, while multiple fractures were evident in five patients. The sites of involvement were the fifth metatarsal (n=10), fourth metatarsal (n=7), third metatarsal (n=3), second metatarsal (n=1), and first metatarsal (n=1) bones. The locations of the stress fractures were in the proximal one-third of the metatarsal bones in 19 instances (86%) and in the middle one-third in three instances (14%). Forefoot adduction angle measured between 21° and 37° (normal range 8°–14°). Conclusion. Patients with metatarsus adductus may be at increased risk for stress fractures involving the lateral metatarsal bones, likely owing to the presence of altered biomechanics that place greater loads across the lateral aspect of the foot. Received: 27 May 1999 Revision requested: 29 July 1999 Revision received: 23 August 1999 Accepted: 26 August 1999     

Mobile-bearing prosthesis did not improve mid-term clinical results of total knee arthroplasty

A prospective study was performed to compare the clinical and radiological results of mobile- and fixed-bearing total knee arthroplasty with specific attention to rotational alignment and range of motion. Sixty-one knees were assigned to total knee arthroplasty with either the NexGen LPS Flex fixed-bearing or with the NexGen LPS Flex mobile-bearing prosthesis. Postoperatively, knees were compared with regard to range of motion, clinical score, and radiographic findings. Rotational alignment of the femoral and tibial components was evaluated by computed tomography. The median follow-up period was 5.9 years (range 2.1–8.8 years). Median postoperative Knee Society scores were 99 points (68–100) for the fixed-bearing group and 100 points (66–100) for the mobile-bearing group (n.s.). The median postoperative flexion angles of 120° (90°–150°) for the fixed-bearing group and 125° (90°–145°) for the mobile-bearing group were not significantly different from each other (n.s.). No knee required revision surgery due to wear of polyethylene or loosening of the component in either group. Computed tomography showed that 11 knees had rotational mismatches of more than 10° between the femoral and tibial components, but no significant difference was found in the postoperative extension and flexion angles or in the clinical score between the two treatment groups. Using the identical design for both fixed- and mobile-bearing prostheses, this prospective, randomized study did not show any clinical advantages of the mobile-bearing knee. Analysis of rotational alignment by CT scan did not reveal a particular advantage of the self-aligning mechanism of mobile-bearing implants.     

A novel standardized algorithm for evaluating patients with painful total knee arthroplasty using combined single photon emission tomography and conventional computerized tomography

SPECT/CT is a promising diagnostic modality in patients with painful total knee arthroplasty (TKA). The purpose of this study is to introduce a novel standardized SPECT/CT algorithm and evaluate its clinical application and reliability. A novel SPECT/CT localization scheme consisting of 9 tibial, 9 femoral and 4 patellar regions on standardized axial, coronal and sagittal slices is proposed. It was piloted in 18 consecutive patients with post TKA pain. The tracer activity on SPECT/CT was recorded using a color-coded scale (0–10). The inter- and intra-observer reliability was assessed for localization and tracer activity. The prosthetic component position was assessed in the CT images after 3D reconstruction using standardized frames of reference. The median inter- and intra-observer differences and ranges of the measured angles were calculated along with the ICC values for inter- and intra-observer reliability. The localization scheme showed very high inter- and intra-observer reliabilities for all regions. The measurement of component position was highly reliable in all cases with sufficient visibility of anatomical landmarks. The median inter-observer difference between alignment measurements for tibial and femoral components was less than 3° (range 0°–6°). The median intra-observer variability for these was less than 2° (range 0°–5°). The SPECT/CT algorithm presented is both reliable and useful in the management of patients with painful TKA. It combines biomechanical and metabolic data (tracer localization) providing an extra dimension to the understanding of this difficult condition. The clinical value of SPECT/CT in patients with unexplained pain following TKA should be further investigated.     

Anatomic variation in the origin of the main renal arteries: spiral CTA evaluation

The aim of this study was to provide quantitative data on the origin and trajectory of the main renal arteries using spiral CT angiography and arteriography. Normal renal artery anatomy was assessed on spiral CT angiography (axial transverse sections and shaded-surface-display reconstructions) in 100 patients referred for renal arteriography who had no significant renal artery stenosis. Two hundred major renal arteries were studied. The vast majority of right (88 %) and left (87 %) renal arteries originated between the lower third of the first lumbar vertebra and the lower border of the second lumbar vertebra. In 50 patients both ostia were at the same level; in the remaining 50 patients, the right ostium was located above the left in 37 patients. On the right, the angle of origin varied from –10 to + 55 ° (mean + 24 °). On the left, the angle of origin varied from + 30 to –55 ° (mean –11 °). Spiral CT angiography provides additional anatomic data, notably regarding the angle of origin of the renal arteries, that is potentially useful for planning interventional procedures. Received: 11 August 1998; Revision received: 30 November 1998; Accepted: 12 February 1998     

What have we learned from LCS mobile-bearing knee system?

Three hundred and sixty-four low contact stress (LCS) total knee arthroplasties that could be followed up for more than 5 years were clinically and radiographically analyzed. The median postoperative Hospital for Special Surgery score improved from 56 (range 32–77) to 91 (range 64–100) points, but median range of motion did not change from 120° (range 50°–135°) to 120° (range 85°–135°). Complications occurred in 16 cases (4%), and included postoperative polyethylene dislocation and intraoperative tibial condylar fracture, while five knees (1%) required revision surgery due to mechanical reasons. The overall prosthesis survival rate was 91% at 12 years. Although the LCS mobile-bearing knee system has theoretical advantages in terms of wear and loosening, the problem of polyethylene dislocation, intraoperative tibial fracture, and radiolucent lines should be solved for long survival. The clinical relevance of this study is that the LCS system provided good clinical and survival results.     

Rotational profile of the lower extremity in achondroplasia: computed tomographic examination of 25 patients

Purpose To evaluate lower-extremity rotational abnormalities in subjects with achondroplasia using computed tomography (CT) scans.Materials and methods CT scans were performed in 25 subjects with achondroplasia (13 skeletally immature, mean age 8.7 years; 12 skeletally mature, mean age 17.6 years). In a total of 50 bilateral limbs, CT images were used to measure the angles of acetabular anteversion, femoral anteversion, and tibial external torion. Measurement was performed by three examiners and then repeated by one examiner. Inter- and intraobserver agreements were analyzed, and results were compared with previously reported normal values.Results Mean values for skeletally immature and skeletally mature subjects were 13.6±7.5° and 21.5±6.4° respectively for acetabular anteversion, 27.1±20.8° and 30.5±20.1° for femoral torsion, and 21.6±10.6° and 22.5±10.8° for tibial torsion. Intra- and interobserver agreements were good to excellent. Acetabular anteversion and femoral anteversion in skeletally mature subjects were greater than normal values in previous studies. Both skeletally immature and mature subjects with achondroplasia had decreased tibial torsion compared to normal skeletally immature and mature subjects.Conclusion Lower-extremity rotational abnormalities in subjects with achondroplasia include decreased tibial external torsion in both skeletally immature and mature subjects, as well as increased femoral and acetabular anteversion in skeletally mature subjects.     

Patient function after a posterior stabilizing total knee arthroplasty: cam–post engagement and knee kinematics

Even though posterior substituting total knee arthroplasty has been widely used in surgery, how the cam–post mechanism (posterior substituting mechanism) affects knee joint kinematics and function in patients is not known. The objective of the present study was to investigate posterior femoral translation, internal tibial rotation, tibiofemoral contact, and cam–post engagement of total knee arthroplasty patients during in vivo weight-bearing flexion. Twenty-four knees with a PS TKA were investigated while performing a single leg weight-bearing lunge from full extension to maximum flexion as images were recorded using a dual fluoroscopic system. The in vivo knee position at each targeted flexion angle was reproduced using 3D TKA models and the fluoroscopic images. The kinematics of the knee was measured from the series of the total knee arthroplasty models. The cam–post engagement was determined when the surface model of the femoral cam overlapped with that of the tibial post. The mean maximum flexion angle for all the subjects was 112.5 ± 13.1°. The mean flexion angle where cam–post engagement was observed was 91.1 ± 10.9°. The femur moved anteriorly from 0° to 30° and posteriorly through the rest of the flexion range. The internal tibial rotation increased approximately 6° from full extension to 90° of flexion and decreased slightly with further flexion. Both the medial and lateral contact point moved posteriorly from 0° to 30°, remained relatively constant from 30° to 90°, and then moved further posterior from 90° to maximum flexion. The in vivo cam–post engagement corresponded to increased posterior translation and reduced internal tibial rotation at high flexion of the posterior substituting total knee arthroplasty. The initial cam–post engagement was also mildly correlated with the maximum flexion angle of the knee (R = 0.51, p = 0.019). A later cam–post engagement might indicate an environment conducive to greater flexion. If the factors that affect cam–post engagement timing can be established, proper manipulation of those factors may improve the function of the knee after posterior substituting total knee arthroplasty.     

The effect of closed wedge high tibial osteotomy on tibial slope: a radiographic study

In recent years there has been a renewed interest in high tibial osteotomies (HTOs). The development of new instruments and better fixation devices has significantly simplified the surgical procedure. This technique is frequently used to correct alignment in the frontal plane. However, changes in the sagittal plane following closed wedge HTO have not been appropriately investigated. Hence, the purpose of this study was to investigate any possible alteration of the tibial slope introduced by closed wedge HTO. In addition, we also investigated whether there is a correlation between changes of the frontal plane and alteration of the tibial slope in the sagittal plane. In a retrospective study, radiographs of 67 patients (41 males, mean age 36.6 and 26 females, mean age 39.4 years) who underwent a closed wedge HTOs or removal of hardware for a previous HTO were reviewed.The frontal plane was corrected by a mean of 7.9° (6–14°). The mean posterior tibial slope on the preoperative images averaged 6.1° (0–12°). The postoperative radiographs demonstrated a significant (P=0.0001) decrease of the posterior tibial slope to a mean of 1.2°. The magnitude of HTO in the frontal plane had no significant effect (P=0.739) on the postsurgical posterior tibial slope in the sagittal plane.     

Percutaneous drainage of psoas abscess under real-time computed tomography fluoroscopic guidance

Objectives  The goal of our study was to determine the usefulness of percutaneous abscess drainage under guidance of computed tomography (CT) fluoroscopy. Materials and methods  Our subjects were 21 patients (seven women, 14 men; mean age 64 years; age range 30–87 years) who had undergone percutaneous drainage of 26 psoas abscess lesions under CT fluoroscopic guidance between May 2001 and January 2008. Drainage methods involved a needle puncture, insertion of a guidewire, serial dilations, and the exchange of the needle with a drainage tube. The procedures were guided by use of a helical CT scanner that provided real-time fluoroscopic reconstruction. Results  Percutaneous drainage under real-time CT fluoroscopic guidance was successfully performed in every procedure. Use of real-time CT fluoroscopy allowed rapid assessment of needle, guidewire, and catheter placement. No patient had serious complications related to the drainage procedure. The mean procedure time required to drain one lesion was 35.6 ± 13.6 min. Mean period after the drainage procedure until complete disappearance of the abscess as confirmed by CT was 12.4 ± 10.0 days (range 3–46 days). Conclusion  CT fluoroscopy is useful in achieving accurate and safe drainage of abnormal psoas fluid collections.     

The relationship between tibial slope and meniscal insertion

Despite increasing interest in the anatomic importance of the meniscal insertion, little information is available regarding the relationship between the tibial slope and the meniscal insertion. Lateral radiographs and MRI sagittal images from 100 healthy and young patients were used in this study. Patients without deformation, meniscal pathology, or previous surgery to the ipsilateral knee were included in this study. We measured the angle between a line tangent to the medial and lateral tibial slope and the proximal tibial anatomical axis using a lateral radiographs. We also measured the angle between the tangent line to the medial and lateral tibial insertion of the meniscus and the proximal tibial anatomical axis using sagittal MRI images. The measurements were carried out twice by two observers. Inter-observer reliability ranged from 0.98 to 0.99 and intra-observer reliability ranged from 0.83 to 0.94. For each observer, the mean differences between measurements made using radiographs and MRI images were 16.4° and 16.4° on the lateral side, respectively, and 6.0° and 5.9° on the medial side, respectively. There was a statistically significant difference between measurements made using radiographs and MRI images (p < 0.001). However, the Pearson’s correlation coefficient between the measurements made using radiographs and MRI images did not show a linear correlation. The measurements of posterior slope on lateral radiographs images and meniscal insertion on sagittal MRI images were reproducible and reliable. Differences in measurements ranged from 15° to 17° on the lateral side and from 5° to 6° on the medial side, with 95% confidence intervals. However, there was no statistical correlation between the measurements made using lateral radiographs and MRI images.     

Navigated open-wedge high tibial osteotomy: advantages and disadvantages compared to the conventional technique in a cadaver study

High tibial osteotomy (HTO) is an established therapy for the treatment of symptomatic varus malaligned knees. A main reason for disappointing clinical results after HTO is the under- and overcorrection of the mechanical axis due to insufficient intraoperative visualisation. Twenty legs of fresh human cadaver were randomly assigned to navigated open-wedge HTO (n=10) or conventional HTO using the cable method (n=10). Regardless of the pre-existing alignment, the aim of all operations was to align the mechanical axis to pass through 80% of the tibial plateau (beginning with 0% at the medial edge of the tibial plateau and ending with 100% at the lateral edge). This overcorrection was chosen to ensure a sufficient amount of correction. Thus, the medial proximal tibia angle (MPTA) increased by 9.1±2.9° (range 5.2°–12.3°) on the average after navigated HTO and by 8.9±2.9° (range 4.7°–12.6°) after conventional HTO. After stabilization with a fixed angle implant, the alignment was measured by CT. After navigated HTO, the mechanical axis passed the tibial plateau through 79.7% (range 75.5–85.8%). In contrast, after conventional HTO, the average intersection of the mechanical axis was at 72.1% (range 60.4–82.4%) (P=0.020). Additionally, the variability of the mean corrections was significantly lower in the navigated group (3.3% vs. 7.2%, P=0.012). Total fluoroscopic radiation time was significantly lower in the navigated group (P=0.038) whereas the mean dose area product was not significantly different (P=0.231). The time of the operative procedure was 23 min shorter after conventional HTO (P<0.001). Navigation systems provide intraoperative 3-dimensional real time control of the frontal, sagittal, and transverse axis and may increase the accuracy of open-wedge HTO. Future studies have to analyse the clinical effects of navigation on corrective osteotomies.     

Compensatory gait deviations in patients with increased outward tibial torsion pre and post tibial derotation osteotomy

BackgroundTibial torsion describes the rotation between the proximal and distal joint axis along the shaft, which can be, as rotational deformity, pathologically increased or decreased. Some patients might increase hip internal rotation during walking to compensate increased outward tibial torsion.Research questionThe aim of this study was to assess the effect of tibial derotation osteotomy on gait deviations in patients with increased outward tibial torsion.MethodsThirteen patients (13.5 ± 1.4 yrs, 22 limbs) with increased tibial torsion (CT confirmed 49.2 ± 4.8°) were analyzed pre and post tibial derotation osteotomy and compared with 17 typically developing children (TDC, 13.5 ± 2.3 yrs, 32 limbs). Kinematic and kinetic data were recorded. Subgroup analyses were performed whether patients showed compensatory hip internal rotation (Comp) or not (NoComp). Principal component (PC) analysis was used to achieve data transformation. A linear mixed model was used to estimate the main effect of PC-scores of retained PCs explaining 90% of the cumulative variance.ResultsCompensatory hip internal rotation (Comp, present in 45.5% of limbs analyzed) led to a lower external foot progression angle compared to patients without compensatory hip internal rotation (NoComp). In both patient groups foot progression angle was normalized after tibial derotation osteotomy. Post-operative NoComp had normalized frontal plane joint loadings, while Comp showed an increased hip and knee adduction moment.SignificanceFuture studies should investigate if more time is needed for Comp to normalize gait patterns post-operative or if a pre and post-operative gait training might help. Otherwise the increased knee adduction moment might be clinically relevant due to previous studies reporting a possible association with knee osteoarthritis.     

A contribution to Pisani’s sign for diagnosing lateral meniscal cysts: a technical report

This article describes modified physical examination maneuvers for diagnosing lateral meniscal cysts. The typical presentation of lateral meniscal cysts usually makes their clinical diagnosis simple, but a wide variation in size may sometimes lead to misdiagnosis. We evaluated the effect of leg rotations on the cystic swelling at 45° of knee flexion. Eleven consecutive patients with positive Pisani’s sign were evaluated prospectively. Lateral mid-third joint-line swelling was most prominent at 30–45° of knee flexion. With the knee held at 45° of flexion, the prominence was also inspected during internal and external rotation of the leg. The masses became noticeably more prominent with external rotation, and completely disappeared with internal rotation. With external rotation of the leg, even doubtful lateral meniscal cysts became apparent. Disappearance of the cystic mass with internal rotation further confirms the diagnosis.     

High tibial osteotomy that does not cause recurrence of varus deformity for medial gonarthrosis

It is widely accepted that high tibial osteotomy (HTO) is an effective surgical treatment for medial gonarthrosis. However, long-term follow-up studies have revealed that the clinical results deteriorate over time and varus deformity often recurs. We performed barrel-vault osteotomy in HTO with a correction angle that did not cause arthritic progression in the medial compartment of the knee or recurrence of varus deformity. Thirty patients (44 knees) were followed clinically and radiographically for a minimum of 10 years (average, 11.4 years). We aimed for an average postoperative femorotibial angle (FTA) of 165.3° (range, 162–169°) according to our method using a correction angle chosen on the basis of the so-called Mikulicz’s mechanical axis. The clinical results were good in 30 (68.2%) knees, fair in 7 (15.9%) and poor in 7 (15.9%). Arthritic progression in the medial compartment was only found in 1 (2.3%) knee, while in the lateral compartment it was found in 17 (38.6%) knees. Of the knees with arthritic progression in the lateral compartment, six (35.3%) were classified as poor. The average postoperative FTAs were 164.3° at 1 year, 164.0° at 5 years and 163.5° at 10 years after the operation, indicating that the knees tended to become slightly valgus over time. The clinical results were not poor after slightly overcorrected osteotomy was performed. Since overcorrection tended to occur, when the preoperative lateral tibial thrust was severe, HTO is not a good indication for such cases.