Tim Alexander Walde

Comparison of CT, MRI, and radiographs in assessing pelvic osteolysis: a cadaveric study.

In this study, we compared the accuracy of radiography, computed tomography, and magnetic resonance imaging in assessing periacetabular osteolytic lesions. Using a previously published cadaver model, we created 87 lesions in pelves implanted with total hip replacement components. The sensitivity for detecting lesions was 51.7% for radiography, 74.7% for computed tomography, and 95.4% for magnetic resonance imaging. For all three techniques, sensitivity increased as lesion size increased. Magnetic resonance imaging emerged as the most effective tool for detecting small periacetabular osteolytic lesions (≤ 3 cm3). For lesions larger than 3 cm3, which are of more concern clinically, computed tomography and magnetic resonance imaging were effective in identifying lesions with detection rates greater than 80%. For radiography and computed tomography, lesion detection was dependent on lesion location, whereas magnetic resonance imaging had consistently good sensitivity in all lesion locations. Although the mean volumetric errors for computed tomography and magnetic resonance imaging (0.3 cm3 and 0.8 cm3) were small compared with mean lesion volume (6.1 cm3), computed tomography was more accurate than magnetic resonance imaging at measuring lesion volume, with a lower mean absolute error. This study verifies the problems associated with radiographic detection of osteolysis while showing the effectiveness of computed tomography and magnetic resonance imaging in determining the presence of lesions and assessing their three-dimensional volume.

Anatomy of Lateral Patellar Instability: Trochlear Dysplasia and Tibial Tubercle–Trochlear Groove Distance Is More Pronounced in Women Who Dislocate the Patella

Background A trend toward young women being at greatest risk for primary and recurrent dislocation of the patella is evident in the current literature. However, a causative factor is missing, and differences in the anatomical risk factors between men and women are less defined. Purpose To identify differences between the sexes in the anatomy of lateral patellar instability. Study Design Case control study; Level of evidence, 3. Methods Knee magnetic resonance images were collected from 100 patients treated for lateral patellar instability. Images were obtained from 157 patients without patellar instability who served as controls. Using 2-way analyses of variance, the influence of patellar dislocation, gender, and their interaction were analyzed with regard to sulcus angle, trochlear depth, trochlear asymmetry, patellar height, and the tibial tubercle—trochlear groove (TT-TG) distance. Mechanisms of injury of first-time dislocations were divided into high-risk, low-risk, and no-risk pivoting activities and direct hits. Results For all response variables, a significant effect was observed for the incidence of patellar dislocation (all P < .01). In addition, sulcus angle, trochlear asymmetry, and trochlear depth depended significantly on gender (all P < .01) but patellar height did not (P = .13). A significant interaction between patellar dislocation and gender was observed for the TT-TG distance (P = .02). The mean difference in TT-TG distance between study and control groups was 4.1 mm for women (P < .01) and 1.6 mm for men (P = .05). Low-risk and no-risk pivoting injuries were most common in women, whereas first-time dislocations in men occurred mostly during high-risk pivoting activities (P < .01). Conclusion The data from this study indicate that trochlear dysplasia and the TT-TG distance is more prominent in women who dislocate the patella. Both factors might contribute to an increased risk of lateral patellar instability in the female patient as illustrated by the fact that dislocations occurred most often during low-risk or no-risk pivoting activities in women.

Magnetic resonance imaging characteristics of the medial patellofemoral ligament lesion in acute lateral patellar dislocations considering trochlear dysplasia, patella alta, and tibial tuberosity-trochlear groove distance.

PURPOSE The objective of this study was to analyze the injury patterns of the medial patellofemoral ligament (MPFL) in acute lateral patellar dislocations (LPDs) considering the anatomically relevant factors of patellar instability. METHODS Knee magnetic resonance images were collected from 73 patients within 7 weeks after LPD, and the injury patterns of the MPFL were evaluated for trochlear dysplasia, for patellar height, and for the tibial tuberosity-trochlear groove (TT-TG) distance. RESULTS Injury to the MPFL was found in 98.6% of the patients (72 of 73) after the acute LPD, with a complete tear in 51.4% (37 of 72), most frequently localized at the femoral attachment site, and a partial tear in 48.6% (35 of 72). Injury to the femoral origin (Fem), to the midsubstance (Mid), and to the patellar insertion (Pat) of the MPFL was found in 50.0% (36 of 72), 13.9% (10 of 72), and 13.9% (10 of 72), respectively. More than 1 site of injury was found in 22.2% (16 of 72), most frequently as a combined injury at the femoral origin and at the patellar insertion sites (Pat+Fem) (13 of 16). The study population, as well as the Pat, Fem, and Pat+Fem subgroups, showed significantly different values of trochlear dysplasia and patellar height when compared with the control group, whereas the data of the Mid group were not significantly different. In addition, injury at the patellar insertion (Pat) was accompanied by a significantly increased TT-TG distance when compared not only with the control group but also with the Fem, Mid, and Pat+Fem groups. CONCLUSIONS The data from our study indicate that patterns of MPFL injury depend on trochlear dysplasia, patellar height, and TT-TG distance. They show a new aspect in the complex interplay between active, passive, and static stabilizers of the patellofemoral joint. LEVEL OF EVIDENCE Level IV, diagnostic case-control study.

A New Posterolateral Approach Without Fibula Osteotomy for the Treatment of Tibial Plateau Fractures

The selection of a surgical approach for the treatment of tibia plateau fractures is an important decision. Approximately 7% of all tibia plateau fractures affect the posterolateral corner. Displaced posterolateral tibia plateau fractures require anatomic articular reduction and buttress plate fixation on the posterior aspect. These aims are difficult to reach through a lateral or anterolateral approach. The standard posterolateral approach with fibula osteotomy and release of the posterolateral corner is a traumatic procedure, which includes the risk of fragment denudation. Isolated posterior approaches do not allow sufficient visual control of fracture reduction, especially if the fracture is complex. Therefore, the aim of this work was to present a surgical approach for posterolateral tibial plateau fractures that both protects the soft tissue and allows for good visual control of fracture reduction. The approach involves a lateral arthrotomy for visualizing the joint surface and a posterolateral approach for the fracture reduction and plate fixation, which are both achieved through one posterolateral skin incision. Using this approach, we achieved reduction of the articular surface and stable fixation in six of seven patients at the final follow-up visit. No complications and no loss of reduction were observed. Additionally, the new posterolateral approach permits direct visual exposure and facilitates the application of a buttress plate. Our approach does not require fibular osteotomy, and fragments of the posterolateral corner do not have to be detached from the soft tissue network.

Computed Tomography in the Assessment of Periacetabular Osteolysis

BACKGROUND Computed tomography recently has been proposed as an accurate method for diagnosing periacetabular osteolytic lesions. Several investigators have attempted to validate the accuracy of this technique, but they employed cadaveric and animal models, which cannot replicate the adaptive changes that occur over time in vivo. This study was performed to determine the accuracy of computed tomography in identifying and measuring periacetabular osteolytic lesions in hemipelves retrieved at autopsies of individuals with a previously well-functioning total hip prosthesis. METHODS We evaluated nine hemipelves, retrieved at autopsy, that contained a cementless porous-coated acetabular component. The fresh specimens were examined with conventional radiographs and computed tomography and then were embedded and sectioned into 1.5-mm slices for evaluation with slab radiographs. Anteroposterior and iliac oblique plain radiographs as well as axial, coronal, and sagittal computed tomography scans were reviewed to determine the presence and location of any periacetabular osteolytic lesions. These results were then compared with those identified on the slab radiographs. Lesion volume was calculated from computed tomography scans with use of post-processing software. RESULTS A total of twenty-three periacetabular osteolytic lesions were identified on the slab radiographs of the nine hemipelves. The plain radiographs identified twelve (52%) of the twenty-three lesions, and the computed tomography scans identified twenty (87%) of the twenty-three lesions. Three medial wall perforations were identified on the computed tomography scans but were not detected on the plain radiographs. Computed tomography was accurate in measuring the volume of the osteolytic lesions (r(2) = 0.997) but tended to overestimate the volumes measured on the slab radiographs. Periacetabular osteolytic lesions appeared on the computed tomography scans and slab radiographs as areas devoid of trabecular bone that were delineated by a sclerotic border and communicated with the joint space. CONCLUSIONS In this autopsy model, computed tomography was an accurate method for detecting the location and measuring the volume of periacetabular osteolytic lesions.

Patellar dislocations in children, adolescents and adults: A comparative MRI study of medial patellofemoral ligament injury patterns and trochlear groove anatomy

PURPOSE The first aim was to compare medial patellofemoral ligament injury patterns in children and adolescents after first-time lateral patellar dislocations with the injury patterns in adults. The second aim was to evaluate the trochlear groove anatomy at different developmental stages of the growing knee joint. MATERIALS AND METHODS Knee magnetic resonance (MR) images were collected from 22 patients after first-time patellar dislocations. The patients were aged 14.2 years (a range of 11-15 years). The injury pattern of the medial patellofemoral ligament was analysed, and trochlear dysplasia was evaluated with regard to sulcus angle, trochlear depth and trochlear asymmetry. The control data consisted of MR images from 21 adult patients who were treated for first-time lateral patellar dislocation. RESULTS After patellar dislocation, injury to the medial patellofemoral ligament was found in 90.2% of the children and in 100% of the adult patients. Injury patterns of the medial patellofemoral ligament were similar between the study group and the control group with regard to injury at the patellar attachment site (Type I), to the midsubstance (Type II) and to injury at the femoral origin (Type III) (all p>0.05). Combined lesions (Type IV) were significantly less frequently observed in adults when compared to the study group (p=0.02). The magnitude of trochlear dysplasia was similar in children, adolescents and adults with regard to all three of the measured parameter-values (all p>0.05). In addition, the articular cartilage had a significant effect on the distal femur geometry in both paediatrics and adults. CONCLUSION First, the data from our study indicated that the paediatric medial patellofemoral ligament injury patterns, as seen on MR images, were similar to those in adults. Second, the trochlear groove anatomy and the magnitude of trochlear dysplasia, respectively, did not differ between adults and paediatrics with patellar instability. Thus, physicians are confronted with similar anatomical risk factors and similar injuries to the medial soft-tissue restraints in children when compared to adults with patellar instability.

Five- to 10-Year Results Using a Noncemented Modular Revision Stem Without Bone Grafting

The aim of the study was to evaluate the 5- to 10-year results (mean, 6.2 years) of a modular uncemented revision stem (Profemur-R). From a total series of 184 consecutive stem revisions, the first 73 were evaluated. The implant was fixed without bone grafting in all cases. The average Harris hip score increased from 40 to 75. A complete remodeling of bone defects could be documented radiographically in 70% of the cases and a partial restoration in 30%. Progressive subsidence appeared in 2 stems. Three rerevisions were required, including 1 septic case. The survival rate with aseptic loosening as the end point was 96% over an average of 10 years. The revision prosthesis examined in this study can be considered a viable and useful option to reconstruct femoral defects in revision hip arthroplasty.

Accuracy of Femoral Tunnel Placement in Medial Patellofemoral Ligament Reconstruction The Effect of a Nearly True-Lateral Fluoroscopic View

Background: Reconstruction of the medial patellofemoral ligament (MPFL) is an established operative procedure for patients with recurrent episodes of lateral patellar instability. However, recent articles have reported remarkable complication rates, with nonanatomic femoral tunnel positioning in up to 64% of patients. Purpose: To evaluate the sensitivity of femoral tunnel placement using lateral fluoroscopic guidance to minor degrees of deviation from the true-lateral view using established radiographic landmarks. Study Design: Controlled laboratory study. Methods: Six human cadaveric femora were used for this study. A 6-mm radiopaque eyelet was used to mark the native femoral insertion of the MPFL according to previously described radiographic landmarks. Radiographic landmarks were also applied with the femur positioned in 2.5° and 5° of internal and external rotation, respectively, and with the femur in 2.5° and 5° of hip abduction and adduction, respectively. The distance between the center of the 6-mm eyelet to the center of the native femoral MPFL insertion, as established in the true-lateral view, was measured and determined as the degree of shift in each position. Results: Hip adduction, abduction, and internal and external rotations of 2.5° resulted in a shift from the native femoral MPFL insertion point to a more distal (adduction), proximal (abduction), anterior (internal rotation), and posterior location (external rotation) of 2.7 ± 0.7, 2.0 ± 0.7, 2.7 ± 1.1, and 3.0 ± 1.3 mm, respectively (all P < .05). Malpositioning increased to a distance of 5.0 ± 0.7 mm distally, 3.6 ± 1.0 mm proximally, 5.2 ± 0.8 mm anteriorly, and 6.2 ± 0.6 mm posteriorly to the native insertion point when the attachment was marked with 5° of divergence from the true-lateral view (all P < .05). Conclusion: The results of this study indicate the high sensitivity of femoral tunnel placement using lateral fluoroscopic guidance to minor degrees of deviation from the true-lateral view. Clinical Relevance: The study highlights the importance of an exact lateral view when fluoroscopic guidance is used for femoral tunnel positioning in the daily practice of MPFL reconstruction, and a possible explanation for the high incidence of nonanatomic tunnel placement is suggested.

Ein modifizierter posterolateraler Zugang für die operative Versorgung von Tibiakopffrakturen

OBJECTIVE Open reduction and internal fixation of posterolateral tibial plateau fractures. INDICATIONS Tibial plateau fractures involving the posterolateral quadrant. CONTRAINDICATIONS Critical soft-tissue conditions. Tibial plateau fractures which do not involve the posterolateral quadrant. SURGICAL TECHNIQUE 90 degrees side positioning on the contralateral side, skin incision along the fibular head, exposure of the peroneal nerve, lateral arthrotomy and exposure of the joint, dissection of the popliteal cavity between the lateral head of the gastrocnemius muscle and soleus muscle. Blunt preparation between popliteus muscle and soleus muscle under preservation of the popliteal artery and vein. Sharp dissection of the soleus muscle from the dorsal parts of fibula and tibia until the peroneal nerve at the fibular neck enters into the muscle. Exposure of the posterolateral tibial head. The dorsal joint capsule and the popliteal corner are prevented from any soft-tissue damage. Visual control of fracture reduction by viewing in the joint gap through lateral arthrotomy. Reduction of the fracture from dorsal with pointed reduction forceps. A conventional or locking radius T-plate can be pinched off with lateral cutters and anatomically bent for fracture fixation and is dorsally fixed at the tibial plateau. POSTOPERATIVE MANAGEMENT 10 kg partial weight bearing for 6-8 weeks. Limited range of motion 0-0-90 degrees for 6 weeks. RESULTS In a period of 2 years, seven patients with posterolateral tibial plateau fractures received open reduction and internal fixation by using the modified posterolateral approach. The patients were examined at follow-up between 12 and 24 months after surgery. Six patients were free of pain with full range of motion and stable knee joints. Radiologically, a good fracture reduction was achieved in six cases. In one patient with a posterolateral comminuted dislocation fracture, a small fracture step and a gap could be observed. No approach-related complications were found.ZusammenfassungOperationszielOffene Reposition und Osteosynthese posterolateraler Tibiakopffrakturen.IndikationenTibiakopffrakturen, die den posterolateralen Quadranten betreffen.KontraindikationenKritische Weichteilverhältnisse.Tibiakopffrakturen, die sich außerhalb des posterolateralen Quadranten befinden.OperationstechnikSeitenlagerung, gerader posterolateraler Hautschnitt über dem Fibulaköpfchen, Darstellung des Nervus peroneus, laterale Arthrotomie und Darstellung der lateralen Gelenkfläche, Präparation in die Kniekehle zwischen lateralem Musculus gastrocnemius und Musculus soleus. Identifikation des Gefäß-Nerven-Bündels (Arteria und Vena popliteae, Nervus tibialis). Stumpfe Präparation zwischen Musculus popliteus und Musculus soleus. Scharfes Ablösen des Musculus soleus von Tibia und Fibula bis knapp oberhalb des Eintritts des Nervus peroneus in die Peronealmuskulatur. Erhalt der Innervation des Musculus soleus. Darstellung des posterolateralen Tibiakopfes. Die dorsale Gelenkkapsel sowie die Popliteusecke werden geschont. Optische Kontrolle der Frakturreposition über die laterale Arthrotomie. Reposition der Fraktur von dorsal, Anmodellieren und Fixieren einer zu einer L-Platte umfunktionierten 3,5-mm-Radius-T-Platte ebenfalls von dorsal.WeiterbehandlungTeilbelastung von 10 kg für 6–8 Wochen, je nach radiologischer Heilung. Limitierung der Kniebeugung auf 90° für 6 Wochen.ErgebnisseIn 2 Jahren wurden sieben Patienten über den modifizierten posterolateralen Zugang operiert. Alle sieben Patienten konnten nach 12–24 Monaten nachuntersucht werden. Sechs Patienten waren beschwerdefrei. Radiologisch zeigte sich sechsmal eine stufenlose Wiederherstellung der Gelenkfläche, einmal fand sich bei einer mehrfragmentären posterolateralen Luxationsfraktur ein verbleibender Defekt mit geringer Stufenbildung. Komplikationen durch den Zugang wurden nicht beobachtet.AbstractObjectiveOpen reduction and internal fixation of posterolateral tibial plateau fractures.IndicationsTibial plateau fractures involving the posterolateral quadrant.ContraindicationsCritical soft-tissue conditions.Tibial plateau fractures which do not involve the posterolateral quadrant.Surgical Technique90° side positioning on the contralateral side, skin incision along the fibular head, exposure of the peroneal nerve, lateral arthrotomy and exposure of the joint, dissection of the popliteal cavity between the lateral head of the gastrocnemius muscle and soleus muscle. Blunt preparation between popliteus muscle and soleus muscle under preservation of the popliteal artery and vein. Sharp dissection of the soleus muscle from the dorsal parts of fibula and tibia until the peroneal nerve at the fibular neck enters into the muscle. Exposure of the posterolateral tibial head. The dorsal joint capsule and the popliteal corner are prevented from any soft-tissue damage. Visual control of fracture reduction by viewing in the joint gap through lateral arthrotomy. Reduction of the fracture from dorsal with pointed reduction forceps. A conventional or locking radius T-plate can be pinched off with lateral cutters and anatomically bent for fracture fixation and is dorsally fixed at the tibial plateau.Postoperative Management10 kg partial weight bearing for 6–8 weeks. Limited range of motion 0-0-90° for 6 weeks.ResultsIn a period of 2 years, seven patients with posterolateral tibial plateau fractures received open reduction and internal fixation by using the modified posterolateral approach. The patients were examined at follow-up between 12 and 24 months after surgery. Six patients were free of pain with full range of motion and stable knee joints. Radiologically, a good fracture reduction was achieved in six cases. In one patient with a posterolateral comminuted dislocation fracture, a small fracture step and a gap could be observed. No approach-related complications were found.

A modified posterolateral approach for the treatment of tibial plateau fractures

OBJECTIVE Open reduction and internal fixation of posterolateral tibial plateau fractures. INDICATIONS Tibial plateau fractures involving the posterolateral quadrant. CONTRAINDICATIONS Critical soft-tissue conditions. Tibial plateau fractures which do not involve the posterolateral quadrant. SURGICAL TECHNIQUE 90 degrees side positioning on the contralateral side, skin incision along the fibular head, exposure of the peroneal nerve, lateral arthrotomy and exposure of the joint, dissection of the popliteal cavity between the lateral head of the gastrocnemius muscle and soleus muscle. Blunt preparation between popliteus muscle and soleus muscle under preservation of the popliteal artery and vein. Sharp dissection of the soleus muscle from the dorsal parts of fibula and tibia until the peroneal nerve at the fibular neck enters into the muscle. Exposure of the posterolateral tibial head. The dorsal joint capsule and the popliteal corner are prevented from any soft-tissue damage. Visual control of fracture reduction by viewing in the joint gap through lateral arthrotomy. Reduction of the fracture from dorsal with pointed reduction forceps. A conventional or locking radius T-plate can be pinched off with lateral cutters and anatomically bent for fracture fixation and is dorsally fixed at the tibial plateau. POSTOPERATIVE MANAGEMENT 10 kg partial weight bearing for 6-8 weeks. Limited range of motion 0-0-90 degrees for 6 weeks. RESULTS In a period of 2 years, seven patients with posterolateral tibial plateau fractures received open reduction and internal fixation by using the modified posterolateral approach. The patients were examined at follow-up between 12 and 24 months after surgery. Six patients were free of pain with full range of motion and stable knee joints. Radiologically, a good fracture reduction was achieved in six cases. In one patient with a posterolateral comminuted dislocation fracture, a small fracture step and a gap could be observed. No approach-related complications were found.ZusammenfassungOperationszielOffene Reposition und Osteosynthese posterolateraler Tibiakopffrakturen.IndikationenTibiakopffrakturen, die den posterolateralen Quadranten betreffen.KontraindikationenKritische Weichteilverhältnisse.Tibiakopffrakturen, die sich außerhalb des posterolateralen Quadranten befinden.OperationstechnikSeitenlagerung, gerader posterolateraler Hautschnitt über dem Fibulaköpfchen, Darstellung des Nervus peroneus, laterale Arthrotomie und Darstellung der lateralen Gelenkfläche, Präparation in die Kniekehle zwischen lateralem Musculus gastrocnemius und Musculus soleus. Identifikation des Gefäß-Nerven-Bündels (Arteria und Vena popliteae, Nervus tibialis). Stumpfe Präparation zwischen Musculus popliteus und Musculus soleus. Scharfes Ablösen des Musculus soleus von Tibia und Fibula bis knapp oberhalb des Eintritts des Nervus peroneus in die Peronealmuskulatur. Erhalt der Innervation des Musculus soleus. Darstellung des posterolateralen Tibiakopfes. Die dorsale Gelenkkapsel sowie die Popliteusecke werden geschont. Optische Kontrolle der Frakturreposition über die laterale Arthrotomie. Reposition der Fraktur von dorsal, Anmodellieren und Fixieren einer zu einer L-Platte umfunktionierten 3,5-mm-Radius-T-Platte ebenfalls von dorsal.WeiterbehandlungTeilbelastung von 10 kg für 6–8 Wochen, je nach radiologischer Heilung. Limitierung der Kniebeugung auf 90° für 6 Wochen.ErgebnisseIn 2 Jahren wurden sieben Patienten über den modifizierten posterolateralen Zugang operiert. Alle sieben Patienten konnten nach 12–24 Monaten nachuntersucht werden. Sechs Patienten waren beschwerdefrei. Radiologisch zeigte sich sechsmal eine stufenlose Wiederherstellung der Gelenkfläche, einmal fand sich bei einer mehrfragmentären posterolateralen Luxationsfraktur ein verbleibender Defekt mit geringer Stufenbildung. Komplikationen durch den Zugang wurden nicht beobachtet.AbstractObjectiveOpen reduction and internal fixation of posterolateral tibial plateau fractures.IndicationsTibial plateau fractures involving the posterolateral quadrant.ContraindicationsCritical soft-tissue conditions.Tibial plateau fractures which do not involve the posterolateral quadrant.Surgical Technique90° side positioning on the contralateral side, skin incision along the fibular head, exposure of the peroneal nerve, lateral arthrotomy and exposure of the joint, dissection of the popliteal cavity between the lateral head of the gastrocnemius muscle and soleus muscle. Blunt preparation between popliteus muscle and soleus muscle under preservation of the popliteal artery and vein. Sharp dissection of the soleus muscle from the dorsal parts of fibula and tibia until the peroneal nerve at the fibular neck enters into the muscle. Exposure of the posterolateral tibial head. The dorsal joint capsule and the popliteal corner are prevented from any soft-tissue damage. Visual control of fracture reduction by viewing in the joint gap through lateral arthrotomy. Reduction of the fracture from dorsal with pointed reduction forceps. A conventional or locking radius T-plate can be pinched off with lateral cutters and anatomically bent for fracture fixation and is dorsally fixed at the tibial plateau.Postoperative Management10 kg partial weight bearing for 6–8 weeks. Limited range of motion 0-0-90° for 6 weeks.ResultsIn a period of 2 years, seven patients with posterolateral tibial plateau fractures received open reduction and internal fixation by using the modified posterolateral approach. The patients were examined at follow-up between 12 and 24 months after surgery. Six patients were free of pain with full range of motion and stable knee joints. Radiologically, a good fracture reduction was achieved in six cases. In one patient with a posterolateral comminuted dislocation fracture, a small fracture step and a gap could be observed. No approach-related complications were found.