Heiko Reichel

Radiological evidence of femoroacetabular impingement in mild slipped capital femoral epiphysis: a mean follow-up of 14.4 years after pinning in situ.

Conventional treatment of mild slipped capital femoral epiphysis consists of fixation in situ with wires or screws. Recent contributions to the literature suggest that even a mild slip may lead to early damage of the acetabular labrum and adjacent cartilage by abutment of a prominent femoral metaphysis. It has been suggested that the appropriate treatment in mild slipped capital femoral epiphysis should not only prevent further slipping of the epiphysis, but also address potential femoroacetabular impingement by restoring the anatomy of the proximal femur. Between October 1984 and December 1995 we treated 16 patients for unilateral mild slipped capital femoral epiphysis by fixation in situ with Kirschner wires. In this study we have reviewed these patients for clinical and radiological evidence of femoroacetabular impingement. There was little clinical indication of impingement but radiological evaluation assessing the femoral head-neck ratio and measuring the Nötzli alpha angle on the anteroposterior and cross-table radiographs showed significant alterations in the proximal femur. None of the affected hips had a normal head-neck ratio and the mean alpha angle was 86 degrees (55 degrees to 99 degrees ) and 55 degrees (40 degrees to 94 degrees ) on the anteroposterior and lateral cross-table radiographs, respectively. While our clinical data favours conventional treatment, our radiological findings are in support of restoring the anatomy of the proximal femur to avoid or delay the development of femoroacetabular impingement following mild slipped capital femoral epiphysis.

Anatomic Reconstruction of the Medial Patellofemoral Ligament in Children and Adolescents With Open Growth Plates Surgical Technique and Clinical Outcome

Background: Recurrent lateral patellar dislocation is a common knee injury in the skeletally immature adolescent. Because of the open physis, operative therapy in children is challenging. This study presents the outcomes of a minimally invasive technique for anatomic reconstruction of the medial patellofemoral ligament (MPFL) in children that respects the distal femoral physis. Hypothesis: Anatomic reconstruction of the MPFL in children that maintains the distal femoral physis will prevent redislocation, preserve the distal femoral physis, and improve knee function. Study Design: Case series; Level of evidence, 4. Methods: Twenty-one consecutive patients with patellofemoral instability and open growth plates underwent anatomic reconstruction of the MPFL that maintained the distal femoral growth plate. Preoperative radiographic examination included AP and lateral views to assess patella alta and limb alignment. Magnetic resonance imaging was performed to evaluate trochlear dysplasia and tibial tubercle–trochlear groove (TT-TG) distance. Evaluation included preoperative and postoperative physical examination, Kujala score, and Tegner activity score. Results: The average age at the time of operation was 12.2 years (range, 10.3-13.9). The average follow-up after operation was 2.8 years after surgery (range, 2.0-3.6). No recurrent dislocation occurred, but 2 patients with high-grade trochlear dysplasia still had a positive apprehension sign. The Kujala score significantly improved from 72.9 (range, 37-87) preoperatively to 92.8 (range, 74-100) postoperatively (P < .01). The Tegner activity score decreased, but not significantly, from 6.0 (range, 3-9) preoperatively to 5.8 (range, 3-9) postoperatively (P = .48). Conclusion: Anatomic reconstruction of the MPFL that respects the distal femoral physis in skeletally immature patients is a safe and effective technique for the treatment of patellofemoral instability and allows patients to return to sports without redislocation of the patella.

Observer Agreement on the Dejour Trochlear Dysplasia Classification A Comparison of True Lateral Radiographs and Axial Magnetic Resonance Images

Background: Trochlear dysplasia is known to be an important cause of patellofemoral instability. D. Dejour’s radiographic and magnetic resonance imaging (MRI) classifications are widely used in clinical practice and in the orthopaedic literature to assess the severity of trochlear dysplasia. The indication for deepening trochleoplasty to treat trochlear dysplasia is also mainly based on the severity of trochlear dysplasia according to Dejour’s criteria. Purpose: To our knowledge, there is no study evaluating the efficacy of the Dejour classification. The aim of this study was to assess the intraobserver and interobserver agreements of the radiographic and MRI-based classification as described by Dejour. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: From 50 patients, 50 lateral radiographs as well as 50 MRI scans were read twice independently within 4 weeks by 4 surgeons (2 senior and 2 junior examiners). Analysis was made according to Dejour’s 4 grades of radiological criteria of trochlear dysplasia as well as differentiating between 2 grades: low-grade (type A) and high-grade trochlear dysplasia (types B-D). Results: The 4-grade analysis showed fair intraobserver and interobserver agreements (24%-78%), while the 2-grade analysis showed good to excellent agreement (56%-96%). The best overall agreement was found for the 2-grade analysis on MRI scans (62%-96%). The lateral radiographs tended to underestimate the severity of trochlear dysplasia compared with axial MRI. Conclusion: D. Dejour’s classification is valid for typing trochlear dysplasia and is particularly useful in separating low-grade from high-grade dysplasia.

Adjacent segment mobility after rigid and semirigid instrumentation of the lumbar spine.

Study Design. Retrospective radiographic analysis of lumbar spine range of motion (ROM) after monosegmental fusion and posterior dynamic stabilization at the level L4–L5. Objective. Comparison of segmental ROM at the index level and the cranial and caudal adjacent levels and of global lumbar spine ROM after monosegmental fusion and posterior dynamic stabilization. Summary of Background Data. The postulated advantage of nonfusion technology compared with fusion is based on the assumption that preservation of motion at the treated segment reduces the incidence of adjacent segment effects. Therefore, it is imperative to provide evidence that dynamic stabilization devices avoid hypermobility at the adjacent segments because this might substantiate a protective effect on the adjacent segments. Methods. Twenty-six patients with low back pain and claudication due to degenerative instability at the level L4–L5 with concomitant spinal stenosis were treated either with decompression and Dynesys (n = 11) or with decompression and fusion (n = 15). All patients underwent flexion/extension radiographs before surgery and at latest follow-up. ROM was assessed at the index level (L4–L5), the cranial/caudal adjacent levels (L3–L4/L5–S1), and at the lumbar spine from L2 to S1. Results. There was a significant reduction of the global ROM of the lumbar spine (L2–S1) and the segmental ROM at the index level (L4–L5) in the fusion group, whereas adjacent level ROM did not change significantly. In the Dynesys group, no significant changes of global lumbar spine ROM (L2–S1) and segmental ROM (index level and cranial/caudal adjacent levels) were seen. Conclusion. This study shows that neither monosegmental instrumented fusion nor monosegmental posterior dynamic stabilization with Dynesys alter the ROM of the cranial and caudal adjacent levels. Consequently, monosegmental posterior dynamic stabilization with Dynesys has no effect with regard to adjacent segment mobility compared with monosegmental fusion.

Primary stability and strain distribution of cementless hip stems as a function of implant design

BACKGROUND Short stem prostheses have been developed to preserve the femoral bone stock. The purpose of this study was to evaluate the stress-shielding effect in the proximal femur as well as the micromotion between bone and implant as a measure of primary stability for a new short stem in comparison to a clinically successful short stem and a straight stem. METHODS Using paired fresh human femurs, stress shielding was examined by using tri-axial strain gage rosettes. The strain distribution of the proximal femur was measured before and after implantation of three cementless prostheses of different design concepts and stem lengths. Furthermore, interface motion and rotational stability were investigated under dynamic loading (100-1600 N) after 100,000 load cycles using inductive miniature displacement transducers. FINDINGS A reduction of longitudinal cortical strains in the proximal femur was displayed for all three implants. The reduction was less pronounced for the shorter stem implants, however. Interface motion was below the critical threshold of 150 μm at almost all measuring points for all three stems, with a tendency for greater rotational stability in the shorter stem implants. INTERPRETATION The new short stem prosthesis displayed reduced stress shielding and comparable primary stability to an established short stem and a conventional shaft design. Shortening the stem did not negatively influence primary stability. The clinical implications of these findings remain to be proven.

Analysis of failed surgery for patellar instability in children with open growth plates

PurposeMany surgical procedures have been proposed to treat recurrent patellar dislocation in children. In recent years, a more tailored approach considering the underlying pathology has been advocated. The aim of the study was to analyze a group of patients with recurrent patellofemoral instability after unsuccessful operative stabilization (Roux-Goldthwait procedure, lateral release, medial reefing or in combination) in childhood and adolescence.MethodsA total of 37 children and adolescents with recurrent patellofemoral instability despite previous surgery were analyzed retrospectively. Radiographic examination included AP and lateral views to assess patella alta and limb alignment. MRI was performed to evaluate trochlear dysplasia and tibial tubercle-trochlear groove (TTTG) distance. As a control group, 23 age- and sex-matched adolescents that were treated with a favorable outcome after medial reefing alone or combined with a Roux-Goldthwait procedure were analyzed.ResultsSevere trochlear dysplasia (type B–D according to Dejour) as detected on MRI scans was found significantly more often in the study group (89%) than in the control group (21%). No statistical difference of patellar height ratio (Insall-Salvati index) and TTTG distance between the two groups could be found.ConclusionOf the measured parameters, only the incidence of trochlear dysplasia was increased. Trochlear dysplasia therefore seems to be a major risk factor for failure of operative stabilization of recurrent patellofemoral instability in children and adolescents. The results in children are in consensus with the literature in adults that a more tailored operative therapy including reconstruction of the MPFL and trochleaplasty has to be considered.Level of evidenceRetrospective study, Level III.

Reconstruction of the Medial Patellofemoral Ligament Clinical Outcomes and Return to Sports

Background: Recent studies have shown that medial patellofemoral ligament (MPFL) reconstruction using a standardized technique provides significant improvements in all outcome scoring systems, with low complication rates and good patient satisfaction. Although numerous studies have assessed clinical results, there is little published literature investigating return to sporting activities after reconstruction of the MPFL. Purpose: To demonstrate postoperative outcomes and the return-to-sports rate a minimum of 2 years after isolated MPFL reconstruction in a young patient cohort. Study Design: Case series; Level of evidence, 4. Methods: Between 2007 and 2010, a total of 72 isolated MPFL reconstructions (in 68 patients) were performed for recurrent patellar dislocation. Pre- and postoperative knee assessment included a thorough history of symptoms and a clinical examination consisting of crepitus, range of motion, patellofemoral pain, and patellar apprehension. Knee function was assessed using the Kujala score, International Knee Documentation Committee score, Tegner activity score, visual analog scale (VAS), and Activity Rating Scale (ARS). Results: Of patients who participated in sports preoperatively (62/68 patients), 100% returned to sports after MPFL reconstruction; 53% returned at equal or higher levels, whereas 47% returned at lower levels. Fifty-four of 68 patients (79.4%) rated themselves as very satisfied or satisfied with the results. The median Kujala score improved significantly from 66 to 87.5 and the median International Knee Documentation Committee score from 60 to 79.8. The median VAS for pain score illustrated significant preoperative to postoperative improvement, from 4 to 2. Conversely, patients’ activity levels according to the Tegner activity score dropped from 4.5 to 4, and the median Activity Rating Scale score dropped from 6 to 3. There was also a persistent instability rate of 10% as well as a slight loss of knee flexion in 24 of 72 knees. Conclusion: Reconstruction of the MPFL is a safe and effective treatment for patellofemoral instability without severe trochlear dysplasia and allows most patients to engage in regular sports activities 2 years postoperatively, at least at a recreational level. However, potential complications, such as persistent instability, pain, and loss of flexion, must be considered.

Prognosis Scores of Tokuhashi and Tomita for Patients With Spinal Metastases of Renal Cancer

BackgroundRetrospective evaluation of the prognosis scores of Tokuhashi and Tomita for life expectancy in 37 consecutive patients with spinal metastases secondary to renal cancer who underwent surgery. The score of Tokuhashi, composed of six parameters, each rated from zero to two, has been proposed in 1990 for the prognostic assessment of patients with spinal metastases. In 2001, Tomita et al. created another prognostic score, composed of three parameters, growth behaviour of the primary tumor (slow, moderate and rapid) and the evidence of visceral and bony metastases.MethodsThirty-seven patients, surgically treated for vertebral metastases secondary to renal cancer were studied. The scores according to Tokuhashi and Tomita were calculated for each patient.ResultsApplying the Tokuhashi Score for the estimation of life expectancy of renal cancer patients with vertebral metastases was found to provide very reliable results with a statistically high significance. The analysis according to Tomita showed no correlation between predicted and real survival. The statistical analysis did not show any significance.ConclusionFor surgical decisions in renal cancer patients with spinal metastases, the prognostic score of Tokuhashi appears to be much more valuable than the Tomita score.

Biomechanical and densitometric bone properties after callus distraction in sheep.

Assessment of biomechanical stability of diaphyseal bone lengthened by callus distraction is an unsolved problem. A middiaphyseal corticotomy was performed in the left tibia of 24 sheep. After 7 days, callus distraction was begun at a rate of 0.5 mm every 12 hours for 30 days using a standard unilateral fixator system. Animals were euthanized 4, 8, or 12 weeks after the end of distraction. The lengthened tibia and the contralateral control tibia from each animal were evaluated by radiographic, densitometric (dual energy xray absorptiometry, quantitative computed tomography), and biomechanical (axial compression testing, torsion testing to failure) methods. The bone mineral density and maximum torque for the lengthened tibia were significantly greater in the 8-week group than in the 4-week group. However, the values in the 12-week group were significantly smaller than in the 8-week group. In the lengthened tibias, there was a correlation between the maximum torque and the bone mineral density, and between the maximum torque and the bone density. Bone density measurements are useful prognosticators for the safe removal of external fixators after leg lengthening procedures. By using these methods, clinical fractures after leg lengthening could be avoided in the future.

Biomechanics of a short stem: In vitro primary stability and stress shielding of a conservative cementless hip stem.

Short stem prostheses provide conservative surgery and favorable metaphyseal load transmission. However, clinical long‐term results are lacking. Therefore, in vitro trials can be used to predict bone‐implant performance. In this in vitro study, primary stability and stress shielding of a new cementless short stem implant was evaluated in comparison to a straight stem using nine pairs of human cadaver femurs. Primary stability, including reversible micromotion and irreversible migration, was assessed in a hip simulator. Furthermore, changes in the pattern of cortical strain were evaluated. The short stem was more resistant to reversible micromotion and irreversible migration into retroversion. Axial stability was similar, with mean reversible micromotions of 9 µm for the short stem and 7 µm for the straight stem. Proximal load transmission was more physiological with the short stem, though both implants could not avoid stress shielding in Gruen zones 1 and 7. Primary stability of the short stem prosthesis was not negatively influenced compared to the straight shaft. Furthermore, proximal femoral strain pattern was more physiological after insertion of the short stem prosthesis. (c) 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1180–1186, 2013