Matthias Klotz

Loosening after acetabular revision: comparison of trabecular metal and reinforcement rings. A systematic review.

The best method of revision acetabular arthroplasty remains unclear. Consequently, we reviewed the literature on the treatment of revision acetabular arthroplasty using revision rings (1541 cases; mean follow-up (FU) 5.7 years) and Trabecular Metal, or TM, implants (1959 cases; mean FU 3.7 years) to determine if a difference with regard to revision failure could be determined. Failure rates of the respective implants were compared statistically using a logistic regression model with adjustment for discrepancies in FU time. In our study, TM shows statistically significant decreased loosening rates relative to revision rings for all grades including severe acetabular defects and pelvic discontinuity. The severe defects appear to benefit the most from TM.

Tibialis Posterior Tendon Transfer Corrects the Foot Drop Component of Cavovarus Foot Deformity in Charcot-Marie-Tooth Disease

BACKGROUND The foot drop component of cavovarus foot deformity in patients with Charcot-Marie-Tooth disease is commonly treated by tendon transfer to provide substitute foot dorsiflexion or by tenodesis to prevent the foot from dropping. Our goals were to use three-dimensional foot analysis to evaluate the outcome of tibialis posterior tendon transfer to the dorsum of the foot and to investigate whether the transfer works as an active substitution or as a tenodesis. METHODS We prospectively studied fourteen patients with Charcot-Marie-Tooth disease and cavovarus foot deformity in whom twenty-three feet were treated with tibialis posterior tendon transfer to correct the foot drop component as part of a foot deformity correction procedure. Five patients underwent unilateral treatment and nine underwent bilateral treatment; only one foot was analyzed in each of the latter patients. Standardized clinical examinations and three-dimensional gait analysis with a special foot model (Heidelberg Foot Measurement Method) were performed before and at a mean of 28.8 months after surgery. RESULTS The three-dimensional gait analysis revealed significant increases in tibiotalar and foot-tibia dorsiflexion during the swing phase after surgery. These increases were accompanied by a significant reduction in maximum plantar flexion at the stance-swing transition but without a reduction in active range of motion. Passive ankle dorsiflexion measured in knee flexion and extension increased significantly without any relevant decrease in passive plantar flexion. The AOFAS (American Orthopaedic Foot & Ankle Society) score improved significantly. CONCLUSIONS Tibialis posterior tendon transfer was effective at correcting the foot drop component of cavovarus foot deformity in patients with Charcot-Marie-Tooth disease, with the transfer apparently working as an active substitution. Although passive plantar flexion was not limited after surgery, active plantar flexion at push-off was significantly reduced and it is unknown whether this reduction was the result of a tenodesis effect or calf muscle weakness.

Motion capture of the upper extremity during activities of daily living in patients with spastic hemiplegic cerebral palsy

Investigations using motion capture to analyze limitations in range of motion (ROM) of the upper extremity in adults with cerebral palsy (CP) are scarce. To evaluate the influence of those limitations on activities of daily living (ADL) and to determine potential mechanisms of compensation, we investigated 15 adults with hemiplegic CP using motion capture while they performed 10 defined ADLs. Data from the nonaffected body side and those from an age-matched able-bodied group were also collected and compared with our subjects. We measured motion of the elbow, shoulder, and trunk and found significant differences in ROM at these sites. The most pronounced reduction in ROM was observed distally in supination and pronation of the elbow. Here, the affected body side of the adults showed a reduction in supination of 45° compared to the able-bodied group. Furthermore we found a correlation between the Manual Ability Classification System (MACS) and the limitations in ROM. In summary, adults with spastic, hemiplegic CP show limitations in ROM accentuated distally during ADLs. The MACS gives conclusive information about those limitations.

Asymmetric pelvic and hip rotation in children with bilateral cerebral palsy: Uni- or bilateral femoral derotation osteotomy?

Internal rotation gait is common among children with bilateral cerebral palsy. However, despite bilaterally increased femoral anteversion asymmetric internal rotation gait is often found. Femoral derotation osteotomy (FDO) is commonly performed bilaterally. Variable functional outcomes are reported especially in cases with mild internal hip rotation during gait and abnormal preoperative pelvic rotation. A major question is if a unilateral treatment of the more involved side in asymmetric cases leads to a comparable or even superior outcome. One hundred and nine children with spastic bilateral CP treated with FDO with pre- and 1-year postoperative 3D gait analysis were retrospectively collected. The asymmetry was calculated from the preoperative difference between both limbs in hip rotation obtained by 3D gait analysis. Twenty-eight children with asymmetry larger than 20° were selected and classified into two groups, according to whether they obtained a unilateral or bilateral FDO. Preoperative clinical examination and pre- and postoperative hip and pelvic rotation in gait analysis on the more and the less involved side did not differ significantly between both groups. Interestingly, in both groups, hip rotation did not change significantly in less-involved limbs, although intraoperative derotation averaged 25°. After unilateral FDO a significant change in pelvic rotation resulted, whereas this was not found after bilateral FDO. The results of this study suggest that unilateral FDO in children with asymmetric internal rotation gait leads to a comparable functional outcome compared to bilateral treatment. Furthermore, it was shown for the first time that considering the asymmetry has a positive effect on pelvic rotation.

The association of equinus and primary genu recurvatum gait in cerebral palsy

Primary genu recurvatum (GR) is less investigated and data presenting the prevalence among patients with bilateral spastic cerebral palsy (BSCP) is lacking in the literature. Equinus is mentioned as one of the main underlying factors in GR, but its influence on the severity and onset type of GR is mainly unanswered, yet. Hence, the purpose of this retrospective study was to assess the prevalence of GR in a large sample size in children with BSCP and to investigate sagittal plane kinematics to evaluate the influence of equinus on different GR types using data of three-dimensional gait analysis. GR was defined as a knee hyperextension of more than one standard deviation of an age matched control group during stance phase in either one or both of the limbs. Primary GR was defined as a GR without having previous surgery regarding the lower extremity, no selective dorsal rhizotomy and/or interventions like botulinum toxin injection, shock wave therapy or serial casting during the last 6 months in the patient history. In a retrospective study 463 patients with BSCP (GMFCS Level I-III) received three-dimensional gait analysis and were scanned for the presence of primary GR. Finally, 37 patients (23 males, 14 females) matched the determined inclusion criteria and were therefore included for further analysis in this study. Out of those patients seven walked with orthoses or a walker and were excluded from further statistical comparison: Kinematics of the lower limbs were compared between patients having severe (knee hyperextension>15°) and moderate (knee hyperextension 5-15°) GR and between patients showing an early (first half of stance phase) and a late (second half of stance phase) GR. Primary GR was present in 37 patients/52 limbs (prevalence 8.0/5.6%). Severe GR was associated with a decreased ankle dorsiflexion compared with moderate GR. Early GR showed an increased knee hyperextension compared to late GR. In conclusion GR is less frequent compared with crouch or stiff gait. Our findings support the importance of equinus as a major underlying factor in primary GR. In this context the influence of equinus seems to be more important in early GR.

Do changes in torsional magnetic resonance imaging reflect improvement in gait after femoral derotation osteotomy in patients with cerebral palsy

PurposeFemoral derotation osteotomy (FDO) is commonly used to correct internal rotation gait (IRG) in spastic diplegia. The purpose of this study was to investigate whether the extent of intraoperative derotation is reflected in changes in static (clinical ROM and anteversion angle measured on torsional MRI) and dynamic parameters (transverse plane kinematics in three-dimensional gait analysis) after FDO in children with spastic diplegia.MethodsIn a prospective study, 30 children with spastic diplegia and IRG were treated with FDO as part of a multilevel surgery and were examined pre- and postoperatively clinically, by three-dimensional gait analysis and by torsional MRI according to a standardised protocol.ResultsA correlation (r = 0.317, p = 0.015) between the extent of intraoperative derotation and mean hip rotation in stance as well as the anteversion angle measured on torsional MRI (r = 0.454, p < 0.001) was found. However, no significant correlation was observed between anteversion angle (tMRI) and mean hip rotation in stance, either before or after FDO.ConclusionsSignificant improvements were found in IRG after FDO, confirming the results of previous studies. There was no correlation between the anteversion measured on MRI and the mean hip rotation in stance in 3D gait analysis before or after FDO. Thus, the data suggest that if the intraoperative extent of derotation is determined only by the anteversion angle, the result will not be better after FDO. It might only help to avoid retroversion and indicate the maximum amount of femoral derotation. In this study the extent of the intraoperative derotation was orientated at the preoperative midpoint of rotation. Based on the small, but significant correlation between the clinical midpoint and the mean hip rotation in stance in the gait analysis, determination of the intraoperative extent of derotation according to the mean hip rotation in stance seems to give the best results.

The stability of the femoral component in the Oxford unicompartmental knee replacement: a comparison of single and twin peg designs

Aseptic loosening of the femoral component is an important indication for revision surgery in unicompartmental knee replacement (UKR). A new design of femoral component with an additional peg was introduced for the cemented Oxford UKR to increase its stability. The purpose of this study was to compare the primary stability of the two designs of component. Medial Oxford UKR was performed in 12 pairs of human cadaver knees. In each pair, one knee received the single peg and one received the twin peg design. Three dimensional micromotion and subsidence of the component in relation to the bone was measured under cyclical loading at flexion of 40° and 70° using an optical measuring system. Wilcoxon matched pairs signed-rank test was performed to detect differences between the two groups. There was no significant difference in the relative micromotion (p = 0.791 and 0.380, respectively) and subsidence (p = 0.301 and 0.176, respectively) of the component between the two groups at both angles of flexion. Both designs of component offered good strength of fixation in this cadaver study.

Reduction in primary genu recurvatum gait after aponeurotic calf muscle lengthening during multilevel surgery.

Knee hyperextension (genu recurvatum, GR) is often seen in children with bilateral spastic cerebral palsy (CP). Primary GR appears essential without previous treatment. As equinus deformity is suspected to be one of the main factors evoking primary GR, the purpose of this study was to determine whether lengthening the calf muscles to decrease equinus would decrease coexisting GR in children with bilateral spastic CP. In a retrospective study, 19 CP patients with primary GR (mean age: 9.4 years, 13 male, 6 female, 26 involved limbs) in whom an aponeurotic calf muscle lengthening procedure was performed during single-event multilevel surgery were included and investigated using three-dimensional gait analysis before and at a mean follow-up of 14 months after the procedure according to a standardized protocol. After calf muscle lengthening, a significant improvement in ankle dorsiflexion (9.5°) and a significant reduction (10.5°) in knee hyperextension (p<0.001) were found during mid-stance of the gait cycle. Six limbs (23%) showed no improvement concerning knee hyperextension and were designated as nonresponders. In these patients no significant improvement in ankle dorsiflexion was found after surgery either. Improvement in ankle dorsiflexion and reduction in knee hyperextension in stance phase correlated significantly (r=0.46; p=0.019). These findings indicate that equinus deformity is a Major underlying factor in Primary GR and that calf muscle lengthening can effectively reduce GR in patients with CP.

Long-term effects after conversion of biarticular to monoarticular muscles compared with musculotendinous lengthening in children with spastic diplegia

Adverse effects such as increased anterior pelvic tilt (APT) are reported after muscle-tendon lengthening (MTL) for the correction of flexed knee gait in cerebral palsy. The conversion of biarticular muscles (CBM) to monoarticular muscles represents an alternative treatment, but only few short-term results have been published, without comparison with MTL. The long-term outcome of 21 diplegic patients treated with CBM in a prospective study was compared with the results in MTL patients in a matched-pair analysis. Standardized clinical examination and three-dimensional gait analysis were done before surgery, 1 year thereafter, and at long-term follow-up a mean of 9.2 years postoperatively. Mean APT increased one year after surgery in both groups. This increase was higher in MTL patients and statistically significant only for this group. Knee flexion at initial contact and minimum knee flexion in stance were significantly decreased in both groups, while in swing the CBM group tended to show more of a decrease in knee flexion but at the cost of reduced peak flexion. Both groups showed deterioration of kinematic knee parameters through to long-term follow-up; the favourable effects of CBM disappeared, and the two groups displayed comparable average pelvic and knee kinematics. Considering individual patterns the prevalence of increased APT was lower in the CBM group 1 year after surgery, indicating that sparing the semitendinosus may have a positive effect on pelvic stability. However, after 9 years 30% of the patients in both groups showed increased APT indicative of persistent hamstring insufficiency. These results demonstrate that CBM, a significantly more extensive procedure, has no long-term advantage over MTL.

Distal femoral extension and shortening osteotomy as a part of multilevel surgery in children with cerebral palsy

BackgroundThere are several reports describing an increase in anterior pelvic tilt after hamstring lengthening in children with cerebral palsy (CP). Distal femoral extension and shortening osteotomy (DFESO) is an alternative treatment for correction of flexed knee gait, but investigations analyzing outcome and influence on adjacent joint are few in the literature. The purpose of this study was to analyze the influence of DFESO on knee and pelvis in children with CP. Furthermore, it was of interest if an additional patellar tendon advancement (PA) influences outcome.MethodsIn this retrospective study, 31 limbs of 22 children (GMFCS I-III; mean age: 12.1±3.1 years), who received DFESO were included and kinematic parameters (knee, pelvis) measured by 3-D-gait analysis were compared before and at least 1 year after surgery (mean follow-up period: 15.6 months).ResultsAfter surgery, during stance phase minimum knee flexion improved significantly by 20.5° (P<0.001) and mean anterior pelvic tilt increased by 4.0 degrees (P=0.045). In 16 limbs, the postoperative increase in maximum anterior pelvic tilt was more than 5°. Limbs who received an additional PA showed the biggest increase in anterior pelvic tilt.ConclusionsDFESO is an effective method for correction of flexed knee gait in children with CP. Furthermore, the results of this study indicate that DFESO may lead to an increase in anterior pelvic tilt, which may lead to a recurrence of flexed knee gait. In this context, PA seemed to aggravate the effect on the pelvis.