Measurement of tibial tuberosity-trochlear groove distance: evaluation of inter- and intraobserver correlation dependent on the severity of trochlear dysplasia.

PURPOSE: Excessive tibial tuberosity-trochlear groove distance (TT-TG) is considered as one of the major risk factors in patellofemoral instability (PFI). TT-TG characterises the lateralisation of the tibial tuberosity and the medialisation of the trochlear groove in the case of trochlear dysplasia. The aim of this study was to assess the inter- and intraobserver reliability of the measurement of TT-TG dependent on the grade of trochlear dysplasia. METHODS: Magnetic resonance imaging (MRI) scans of 99 consecutive knee joints were analysed retrospectively. Hereof, 61 knee joints presented with a history of PFI and 38 had no symptoms of PFI. After synopsis of the axial MRI scans with true lateral radiographs of the knee, the 61 knees presenting with PFI were assessed in terms of trochlear dysplasia. The knees were distributed according to the four-type classification system described by Dejour. RESULTS: Regarding interobserver correlation for the measurements of TT-TG in trochlear dysplasia, we found r=0.89 (type A), r=0.90 (type B), r=0.74 (type C) and 0.62 (type D) for Pearson's correlation coefficient. Regarding intraobserver correlation, we calculated r=0.89 (type A), r=0.91 (type B), r=0.77 (type C) and r=0.71 (type D), respectively. Pearson's correlation coefficient for the measurement of TT-TG in normal knees resulted in r=0.87 for interobserver correlation and r=0.90 for intraobserver correlation. CONCLUSION: Decreasing inter- and intraobserver correlation for the measurement of TT-TG with increasing severity of trochlear dysplasia was detected. In our opinion, the measurement of TT-TG is of significance in low-grade trochlear dysplasia. The final decision to perform a distal realignment procedure based on a pathological TT-TG in the presence of high-grade trochlear dysplasia should be reassessed properly. LEVEL OF EVIDENCE: Retrospective study, Level II.

Analysis of failure and clinical outcome after unsuccessful medial patellofemoral ligament reconstruction in young patients.

PURPOSE: Reconstruction of the medial patellofemoral ligament (MPFL) has become a popular procedure for patients with patellofemoral instability. Nevertheless, complication rates of up to 26 % have been reported. This study presents the analysis of failure and clinical outcome of subsequent revision surgery in young patients following unsuccessful medial patellofemoral ligament reconstruction. METHODS: Nineteen consecutive patients with unsuccessful MPFL reconstruction underwent revision surgery. Pre-operative assessment included physical examination, radiographs and magnetic resonance imaging to assess the MPFL graft, trochlear dysplasia, tibial tubercle-trochlear groove (TT-TG) distance, patella alta and femoral tunnel positioning. Evaluation also included the detection of cartilage injuries as well as visual analog scale (VAS), knee function scores and patient satisfaction. Each complication was analysed and an appropriate revision procedure was performed according to the identified technical or untreated anatomical risk factor. RESULTS: The average age at the time of the index operation was 20.2 years (range, 16-27 years). The average age at the time of the primary MPFL reconstruction was 18.4 years (range, 15-25). Three main reasons for failure after MPFL reconstruction could be identified: failure to consider additional risk factors, intra-operative technical errors and inappropriate patient selection. In five patients severe trochlear dysplasia and in two patients concomitant excessive femoral anteversion as additional risk factors were detected. Seven patients experienced medial retinacular pain with limited flexion due to technical errors caused in three patients by anterior placement of the femoral tunnel and in four others by overtensioning of the MPFL graft. Four patients with patellofemoral pain were found to have ICRS grade III or IV cartilage injuries. The median postoperative Kujala scores improved from 57 (34 - 73) pre-operatively to 83 (49 - 94), the median knee function improved from 5 (range, 2 - 6) pre-operatively to 8 (range, 3 - 10). Median VAS scores improved from 4 (2 - 7) to 2 (0 - 5). A total of 78.9% of patients were satisfied or very satisfied, 15.8% were partially satisfied and one patient (5.3%) was not satisfied with the result after revision surgery. CONCLUSION: Failure to consider additional risk factors, technical intra-operative errors and inappropriate patient selection were identified as reasons for revision surgery after MPFL reconstruction. Identifying the potential causes of failure can help to treat and possibly prevent future complications.

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

PURPOSE: Many 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. METHODS: A 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. RESULTS: Severe 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. CONCLUSION: Of 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 EVIDENCE: Retrospective study, Level III.

Reliability of radiographic signs for acetabular retroversion.

Acetabular retroversion may contribute to femoroacetabular impingement and lead to osteoarthritis of the hip. Retroversion has been measured on computed tomography scans. In recent years, assessment of acetabular version on anteroposterior pelvic views has gained increasing attention. We therefore aimed to determine the reliability of radiographic signs of acetabular retroversion and its association with the rater's experience. Five orthopedic surgeons (o1 to o5) rated the crossover sign, ischial spine sign and posterior wall sign on X-rays of 40 hip joints. Also, we determined the rater's experience in recognizing acetabular retroversion with a questionnaire and correlated intraobserver reliability to the calculated experience score. The intraobserver results were 0.325 (o1), 0.848 (o2), 0.684 (o3), 0.701 (o4), and 1.000 (o5) for the crossover sign, 0.750 (o1), 0.890 (o2), 0.593 (o3), 0.483 (o4), and 0.946 (o5) for the posterior wall sign; and 0.578 (o1), 0.680 (o2), 0.595 (o3), 0.375 (o4), and 0.800 (o5) for the ischial spine sign. Interobserver reliability was 0.514 for the crossover, 0.633 for the posterior, and 0.543 for the ischial spine sign wall. The experience sum score correlated to the kappa results for the crossover (r = 0.527), posterior wall (r = 0.738), and ischial spine sign (r = 0.949). Assessing acetabular version on plain radiographs is subject to intra- and interindividual error and related to the observer's individual experience.

Intraarticular lesions in calcifying tendinitis: incidence and association with the acromion index.

INTRODUCTION: Intraarticular pathologies are a common finding during arthroscopy for rotator cuff lesions. Both rotator cuff tears as well as cartilage lesions have been described as correlating with the acromion index. METHODS: In the current study, we aimed to determine the incidence of intraarticular lesions in calcifying tendinitis, to compare the incidence in patients with partial- and full-thickness tears of the rotator cuff, and to determine the acromion index in these groups. The incidence and type of accompanying intraarticular lesions were compared between three consecutive, age-matched groups of 64 patients each: those with calcifying tendinitis (group A), and those with partial- (group B) and full-thickness rotator cuff tears (group C). Also, the acromion index was measured from plain radiographs and compared between the groups. RESULTS: The incidence of intraarticular pathology was 43% in group A, 41% in group B and 84% in group C. The differences between groups A and C as well as B and C were significant (p < 0.0001), but not between groups A and B (p = 0.858). Even though the acromion index was larger in group C than in the other two groups, the difference was not significant (A vs. B, p = 0.505; A vs. C, p = 0.180; and B vs. C p = 0.446). The incidence and type of intraarticular lesions in calcifying tendinitis are comparable to age-matched shoulders with partial- rather than full-thickness rotator cuff tears. CONCLUSION: The acromion index is not different between shoulders with calcifying tendinitis, and partial- or full-thickness rotator cuff tears.

Dysplasia epiphysealis hemimelica: a case report with novel pathophysiologic aspects.

Dysplasia epiphysealis hemimelica (DEH) is a rare developmental disorder. The underlying pathophysiology is largely unclear. Its diagnosis is based on clinical findings and may be difficult due to its low incidence and close relationship to other disorders such as osteochondroma. We describe a 13-year-old boy who presented with a unilateral lesion of the left medial femoral condyle and left ankle. In addition to standard diagnostic tools such as radiographs and MRI, arthroscopy-guided biopsy was performed; histologic/immunohistochemical findings from cartilage-bone specimens confirmed the diagnosis and provided novel information toward a disease mechanism. The cellular phenotype of clustered chondrocytes exhibited characteristics of chondroprogenitor cells and terminally differentiated cells, suggesting dysregulation of resident progenitor cells. No other surgery was performed and during a 2 year period, we observed spontaneous ossification of the lesion associated with decreased joint impairment. Immunohistochemical analysis of the lesion provided a more accurate diagnosis and may contribute to unraveling potential novel mechanisms involved in its pathogenesis.

Impact of five different medial patellofemoral ligament-reconstruction strategies and three different graft pre-tensioning states on the mean patellofemoral contact pressure: a biomechanical study on human cadaver knees.

BACKGROUND: The medial patellofemoral ligament (MPFL) is the main stabiliser of the patella and thus mostly reconstructed in the surgical treatment of patellofemoral dislocation. The aims of this study were to gain a better understanding of the influence of altered MPFL graft-fixation locations and different graft pre-tensions on patellofemoral contact pressure. METHODS: Six human cadaveric knee joints were placed in a six-degree-of-freedom knee simulator. Mean PFCP (mPFCP) was evaluated in knee flexion of 0, 30 and 90° using a calibrated pressure-measurement system. After data assessment of the native knee joint, five MPFL reconstruction conditions were conducted: Anatomical double bundle; non-anatomical proximal patellar; non-anatomical distal patellar; non-anatomical proximal femoral; non-anatomical ventral femoral. The gracilis graft was fixed at a defined knee flexion of 30° and pre-tensioned to 2, 10 and 20 N. RESULTS: Kruskal-Wallis testing resulted in no mPFCP differences between the native and anatomical reconstruction states. Comparing the native and anatomical reconstruction states with the non-anatomical reconstruction states, no difference in the mPFCP both in knee extension (0°) (p>0.366) and in 30° knee flexion (p>0.349) was found. At 90° knee flexion, the following differences were identified: compared to the native knee state, the mPFCP increased after non-anatomical proximal femoral and non-anatomical ventral femoral reconstruction by 257% (p=0.04) and 292% (p=0.016), respectively. Compared to the anatomical reconstruction state, the mPFCP increased after non-anatomical proximal femoral reconstruction by 199% (p=0.042). DISCUSSION AND CONCLUSIONS: With respect to all study findings and to restore a physiological PFCP, we recommend using the anatomical footprints for MPFL reconstruction and a moderate graft pretensioning of 2-10 N.

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.

Combined trochleoplasty and medial patellofemoral ligament reconstruction for recurrent patellar dislocations in severe trochlear dysplasia: a minimum 2-year follow-up study.

BACKGROUND: Trochlear dysplasia is an important etiological factor for the development of patellofemoral instability. Because a dislocation of the patella as a result of trochlear dysplasia results in a traumatic disruption of the medial patellofemoral ligament (MPFL), a combined trochleoplasty and patellofemoral ligament reconstruction appears to be the most appropriate procedure to treat patients with severe trochlear dysplasia. HYPOTHESIS: Combined trochleoplasty and anatomic reconstruction of the MPFL will prevent redislocations of the patella and will lead to improved knee function. STUDY DESIGN: Case series; Level of evidence, 3. METHODS: Twenty-three consecutive patients (26 knees) with patellofemoral instability and severe trochlear dysplasia underwent combined trochleoplasty and anatomic reconstruction of the MPFL. Preoperative radiographic examination included anteroposterior and lateral views to assess patella alta. Magnetic resonance imaging was performed to evaluate trochlear dysplasia and the tibial tubercle-trochlear groove (TT-TG) distance. Evaluations included the detection of cartilage injuries, preoperative and postoperative physical examinations, and scores for the visual analog scale (VAS), Kujala knee function, International Knee Documentation Committee (IKDC), activity rating scale (ARS), and Tegner activity scale. RESULTS: The mean age at the time of operation was 19.2 years (range, 15.4-23.6 years). The mean follow-up after operation was 2.5 years after surgery (range, 2.0-3.5 years). No recurrent dislocation occurred postoperatively. Kujala scores improved from 79 to 96, IKDC scores from 74 to 90, and VAS scores from 3 to 1. All improvements were highly statistically significant (P < .01). The activity level according to the Tegner activity scale and the ARS decreased but was not statistically significant (P = .06 and P = .21, respectively). There were 95.7% of the patients who were satisfied or very satisfied with the procedure. CONCLUSION: Combined anatomic reconstruction of the MPFL and trochleoplasty reliably improved the stability of the patellofemoral joint in patients with severe trochlear dysplasia and no or mild degenerative changes. In addition, the described procedure showed significant improvement of knee function and good patient satisfaction without any episode of redislocations of the patella.

Permanent patellar dislocation after a nonoperative treatment of recurrent dislocation of the patella because of trochlear dysplasia: a case report and review of the literature.

Patellar instability is a common knee injury in children and adolescents. After first-time dislocation, a nonoperative course is widespread. In cases of recurrent patellar dislocation, operative therapy is widely recommended. This case report shows the complicating history after a period of numerous patellar dislocations with primarily spontaneous reduction and a nonreducible dislocation at the follow-up 2 years after a nonoperative treatment.

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.

Mid-term results after ultrasound-monitored treatment of developmental dysplasia of the hips: to what extent can a physiological development be expected?

The purpose of this study was to evaluate the radiological outcome after ultrasound-monitored treatment of developmental dysplasia of the hip at the age of 3 years. We retrospectively reviewed the findings of the second radiographic follow-up of 72 consecutive infants (mean age 31.3 months) with residual developmental dysplasia of the hip. Statistical analysis showed significant regression of acetabular index. Nevertheless, nine hips in seven children showed substantial residual dysplasia. Although remodelling of the acetabulum can be expected, there remains a risk of residual dysplasia. For this reason, radiographic follow-up of every once treated hip as well as the initially physiological contralateral hip is necessary.

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.

Radiological criteria for trochlear dysplasia in children and adolescents.

Trochlear dysplasia is a well-known cause for recurrent patellar instability. Besides clinical findings, the treatment is based on radiological diagnostic tools. In adults the characteristics of trochlear dysplasia are determined by magnetic resonance imaging (MRI) scans as well as on true lateral radiographs. For children there are no established criteria for the radiological diagnosis of trochlear dysplasia. This study was designed to evaluate if typical radiological findings of trochlear dysplasia on lateral radiographs in adults are also found in children and adolescents with open growth plates. We analyzed true lateral radiographs of children and adolescents with MRI-detected trochlear dysplasia. On lateral radiographs three factors were relevant: crossing sign (deepest part of the trochlea crosses the most anterior point of the lateral condyle), a supratrochlear spur or bump (bulge of the proximal trochlea), and a double contour (due to a hypoplastic medial condyle). In all patients with trochlear dysplasia at least one typical radiological finding usually found in adults could be documented. Only true lateral radiographs allow the diagnosis of trochlear dysplasia in children and adolescents with open physis to be made. MRI scans on a regular basis are, therefore, not mandatory although they are the diagnostic golden standard for the diagnosis of trochlear dysplasia.

Perthes disease: current principles of diagnosis and treatment.

BACKGROUND: Because the course of Legg-Calvé-Perthes disease (LCPD) is highly variable, its appropriate diagnostic evaluation and treatment are still debated. METHODS: The authors selectively review the literature, present their own study findings, and discuss the guidelines of the German Society for Orthopedics and Orthopedic Surgery. RESULTS: The main prognostic factors are the patient's age at the onset of the disease, the degree of limitation of range of motion, the extent of involvement of the femoral epiphysis, and any additional radiographic "head-at-risk" signs. Depending on the severity of the disease, the treatment options range from observation and frequent follow-up to reconstructive hip surgery. The goal of all treatments is to prevent a prearthrotic deformity and the ensuing premature coxarthrosis. This goal is best met by adherence to the principle of containment, i.e., the maintenance or restoration of joint congruence while biological plasticity is still present. CONCLUSIONS: In view of the variable course of LCPD, the proper course of treatment must be determined individually in each case. Every child with LCPD must receive individually adapted treatment and continued follow-up into adulthood.