Magnetic resonance imaging for assessment of the quadriceps tendon cross-sectional area as an adjunctive diagnostic parameter in patients with patellofemoral pain syndrome.

OBJECTIVES: In this study, we aimed to provide a more valuable diagnostic parameter and more equivocal assessment of the diagnostic potential of patellofemoral pain syndrome (PFPS) by comparing the quadriceps tendon cross-sectional area (QTCSA) with the quadriceps tendon thickness (QTT), a traditional measure of quadriceps tendon hypertrophy. PATIENTS AND METHODS: Between March 2014 and August 2020, a total of 30 patients with PFPS (16 males, 14 females; mean age, 30.4±11.2 years; range, 16 to 49 years) and 30 healthy individuals (19 males, 11 females; mean age: 30.8±13.8 years; range, 17 to 62 years) who underwent knee magnetic resonance imaging (MRI) were retrospectively analyzed. T1-weighted turbo spin-echo transverse MRI scans were obtained. The QTCSA was measured on the axial angled phases of the images by drawing outlines, and the QTT was measured at the most hypertrophied quadriceps tendon. RESULTS: The mean QTT and QTCSA in the patients with PFPS (6.33±0.80 mm and 155.77±36.60 mm2, respectively) were significantly higher than those in the control group (5.77±0.36 mm and 111.90±24.10 mm2, respectively; p<0.001, for both). The receiver operating characteristic curve was used to confirm the sensitivities and specificities for both the QTT and QTCSA as predictors of PFPS. The optimal diagnostic cut-off value for QTT was 5.98 mm, with a sensitivity of 66.7%, a specificity of 70.0%, and an area under the curve (AUC) of 0.75 (range, 0.62 to 0.88). The optimal diagnostic cut-off value for QTCSA was 121.04 mm2, with a sensitivity of 73.3%, a specificity of 70.0%, and an AUC of 0.83 (range, 0.74 to 0.93). CONCLUSION: Based on our study results, the QTCSA seems to be a more reliable diagnostic indicator for PFPS than QTT.

Excessive femoral torsion is not associated with patellofemoral pain or instability if TKA is functionally aligned and the patella denervated.

PURPOSE: Recent data suggest that individual morphologic factors should be respected to restore preoperative patellofemoral alignment and thus reduce the likelihood of anterior knee pain. The goal of this study was to investigate the effect of excessive femoral torsion (FT) on clinical outcome of TKA. METHODS: Patients who underwent TKA and complete preoperative radiographic evaluation including a long-leg radiograph and CT scan were included. 51 patients showed increased FT of > 20° and were matched for age/sex to 51 controls (FT < 20°). Thirteen patients were lost to follow-up. Thirty-eight matched pairs were compared after a 2 year follow-up clinically (Kujala and patellofemoral score for TKA) and radiographically (FT, frontal leg axis, TT-TG, patellar thickness, patellar tilt, and lateral displacement of patella). Functional alignment of TKA was performed (hybrid-technique). All patellae were denervated but no patella was resurfaced. RESULTS: There was no significant difference between clinical scores two years after surgery between patients with normal and excessive FT (n.s.). Kujala score was 64.3 ± 16.7 versus 64.8 ± 14.4 (n.s.), and patellofemoral score for TKA was 74.3 ± 21 versus 78.5 ± 20.7 (n.s.) for increased FT group and control group, respectively. There was no correlation between preoperative FT and clinical scores. Other radiographic parameters were similar between both groups. No correlations between clinical outcomes and preoperative/postoperative frontal leg axis or total leg axis correction were found (n.s.). CONCLUSION: If the leg axis deformity is corrected to a roughly neutral alignment during cemented TKA, including patellar denervation, then excessive FT was not associated with patellofemoral pain or instability. LEVEL OF EVIDENCE: Prospective comparative study, level II.

Dose atrophy of vastus medialis obliquus and vastus lateralis exist in patients with patellofemoral pain syndrome.

BACKGROUND: Whether vastus medialis obliquus atrophy exists in patients with patellofemoral pain syndrome and whether the amount of atrophy differs between the vastus medialis obliquus and vastus lateralis muscles remain unknown. MATERIALS: From June 2016 to March 2019, 61 patients with patellofemoral pain syndrome were retrospectively included in the study group, and an age-, sex-, and body mass index-matched cohort of 61 patients with normal knees was randomly selected as the control group. All enrolled subjects had undergone CT scans in the supine position. The cross-sectional areas of the vastus medialis obliquus and the vastus lateralis muscle in the sections 0, 5, 10, 15, and 20 mm above the upper pole of the patella were measured, and the vastus medialis obliquus/vastus lateralis muscle area ratio was evaluated. RESULTS: In the study group, the vastus medialis obliquus areas and the vastus lateralis muscle areas in the sections that were 0, 5, 10, 15, and 20 mm above the upper pole of the patella were significantly smaller than the respective areas in the control group (P < 0.05). The vastus medialis obliquus/vastus lateralis muscle area ratio was significantly smaller at the upper pole of the patella (the section 0 mm above the upper pole of the patella) than the corresponding ratio in the control group (P < 0.05). No significant difference was noted between the two groups in the sections 5, 10, 15, and 20 mm above the upper pole of the patella (P > 0.05). CONCLUSION: In patients with patellofemoral pain syndrome, vastus medialis obliquus and vastus lateralis muscle atrophy existed in sections 0-20 mm above the upper pole of the patella, compared with normal controls, and atrophy of the vastus medialis obliquus was more evident than that of the vastus lateralis muscle at the upper pole of the patella. These findings support the rationale for the use of general quadriceps exercise combined with vastus medialis obliquus strengthening exercise as part of the rehabilitation programme for the patients with patellofemoral pain syndrome.

The effect of patellofemoral pain syndrome on patellofemoral joint kinematics under upright weight-bearing conditions.

Patellofemoral pain (PFP) is commonly caused by abnormal pressure on the knee due to excessive load while standing, squatting, or going up or down stairs. To better understand the pathophysiology of PFP, we conducted a noninvasive patellar tracking study using a C-arm computed tomography (CT) scanner to assess the non-weight-bearing condition at 0° knee flexion (NWB0°) in supine, weight-bearing at 0° (WB0°) when upright, and at 30° (WB30°) in a squat. Three-dimensional (3D) CT images were obtained from patients with PFP (12 women, 6 men; mean age, 31 ± 9 years; mean weight, 68 ± 9 kg) and control subjects (8 women, 10 men; mean age, 39 ± 15 years; mean weight, 71 ± 13 kg). Six 3D-landmarks on the patella and femur were used to establish a joint coordinate system (JCS) and kinematic degrees of freedom (DoF) values on the JCS were obtained: patellar tilt (PT, °), patellar flexion (PF, °), patellar rotation (PR, °), patellar lateral-medial shift (PTx, mm), patellar proximal-distal shift (PTy, mm), and patellar anterior-posterior shift (PTz, mm). Tests for statistical significance (p < 0.05) showed that the PF during WB30°, the PTy during NWB0°, and the PTz during NWB0°, WB0°, and WB30° showed clear differences between the patients with PFP and healthy controls. In particular, the PF during WB30° (17.62°, extension) and the PTz during WB0° (72.5‬0 mm, posterior) had the largest rotational and translational differences (JCS Δ = patients with PFP-controls), respectively. The JCS coordinates with statistically significant difference can serve as key biomarkers of patellar motion when evaluating a patient suspected of having PFP. The proposed method could reveal diagnostic biomarkers for accurately identifying PFP patients and be an effective addition to clinical diagnosis before surgery and to help plan rehabilitation strategies.

Should the meniscal height be considered for preoperative sizing in meniscal transplantation?

PURPOSE AND HYPOTHESIS: In preoperative sizing for meniscal transplantation, most authors take into consideration the length and width of the original meniscus, but not its height. This study aimed at evaluating (1) whether the meniscal height is associated with the meniscal length and width, (2) whether the heights of the meniscal segments are associated with the individual's anthropometric data, (3) whether the heights of the meniscal segments are associated with each other in the same meniscus, and (4) the degree of symmetry of the meniscal dimensions between the right and left knees. METHODS: In this cross-sectional, observational study, two independent radiologists measured the meniscal length, width and height in knee magnetic resonance imaging scans obtained from 25 patients with patello-femoral pain syndrome. Reproducibility of measurements was calculated with intraclass correlation coefficients. Associations between the anthropometric data and the meniscal measurements, the meniscal length and width versus height, and the heights of the meniscal segments in the same meniscus were examined with Pearson's correlation. RESULTS: Inter-observer reliability was excellent (>0.8) for length and height and good (0.6-0.8) for width measurements. There was also excellent agreement (>0.8) for the length and width of the menisci in the right and left knees. The heights of the horns of the lateral meniscus showed good agreement (0.6-0.8), while the heights of the other meniscal segments had excellent agreement between the sides (>0.8). There were significant associations with generally low (r < 0.5) correlation between the heights of the meniscal segments and the lengths and widths of the menisci, between the meniscal height and anthropometric data, and between the heights of the meniscal segments in the same meniscus. Correlations between anthropometric data and meniscal length and width were generally high (r > 0.7). CONCLUSIONS: There was excellent agreement between the meniscal dimensions of the right and left knees, and a weak association between the meniscal height with the meniscal width and length, between the height of the menisci with anthropometric data and between the heights of the segments in the same meniscus. The height of the meniscal segments may be a new variable in preoperative meniscal measurement.

Relationship Between Posterior-Inferior Tibial Slope and Bilateral Noncontact ACL Injury.

Is there a correlation between increased posterior-inferior tibial slope angle and noncontact anterior cruciate ligament (ACL) injury? Does increasing the posterior-inferior tibial slope angle increase the risk of bilateral ACL injury? A computerized relational database (Access 2007; Microsoft Inc, Redmond, Washington) was used to conduct a retrospective review of patients undergoing bilateral or unilateral ACL reconstruction surgery or treatment by a single surgeon between 1995 and 2013. Included in the study were patients with bilateral and unilateral ACL injuries and patellofemoral pain syndrome with no associated ACL deficiency. Exclusion criteria included concomitant ligament injury, previous ACL reconstruction, and previous knee surgery. Also excluded were patients who did not have plain lateral radiographs. Fifty patients were randomly selected from each group. After controlling for age and Tegner activity level, the authors found that the posterior-inferior tibial slope angle was a significant predictor (P=.002) of noncontact ACL injury. Mean posterior-inferior tibial slope angle for the bilateral, unilateral, and control groups was 11.8°±2.3°, 9.3°±2.4°, and 7.5°±2.3°, respectively. In the group with unilateral ACL injury vs the group without ACL deficiency, a 1° increase in posterior-inferior tibial slope angle (P=.03) was associated with a 20% increase in unilateral ACL injury. In those with bilateral ACL injury vs those without ACL deficiency, a 1° increase in posterior-inferior tibial slope angle (P=.001) increased bilateral knee injury by 34%. The difference between the mean angles of the control group without ACL deficiency and both the bilateral injury and unilateral injury cohorts was statistically significant (P=.003). Increased posterior-inferior tibial slope angle is associated with an increased risk of noncontact bilateral and unilateral ACL injury. [Orthopedics. 2017; 40(1):e136-e140.].

Bone scan usefulness in patients with painful hip or knee prosthesis: 10 situations that can cause pain, other than loosening and infection.

In recent years, with the higher median life expectancy, the number of hip and knee replacements has increased. Clinical examination and morphological studies are essential to evaluate patients with a painful arthroplasty. Nuclear medicine examinations also play an important role, their main usefulness being the exclusion of prosthesis complications. Nevertheless, conventional examinations, namely bone scan and white blood cell scintigraphy, can also identify complications, such as loosening and infection. This study describes the normal and pathologic patterns of a bone scan and exemplifies ten common situations that can cause pain in patients with hip or knee arthroplasty, other than loosening and infection, which can be disclosed on a bone scintigraphy. The ten situations that should be considered and looked for when analysing a bone scan are: referred pain, patellofemoral pain syndrome, fractures, fissures, abscess/haematoma, bone insert behaviour, heterotopic ossification, greater trochanter pseudarthrosis, osteoarthritis extension in a knee with an unicompartmental prosthesis, and systemic disease with bone involvement.

Does Patella Tendon Tenodesis Improve Tibial Tubercle Distalization in Treating Patella Alta? A Computational Study.

BACKGROUND: Patellofemoral malalignment associated with patella alta may cause pain and arthritis; because of this, the condition sometimes is treated surgically. Two common procedures are tibial tubercle distalization with or without patellar tendon tenodesis. However, the biomechanical consequences of these interventions for patella alta are not clearly understood. QUESTIONS/PURPOSES: We evaluated changes in patellofemoral joint contact mechanics after tibial tubercle distalization and tibial tubercle distalization combined with patella tendon tenodesis. Specifically, we asked: (1) Are there biomechanical differences between these two types of procedures? (2) Is there an ideal range to distalize the patella? METHODS: Subject-specific finite-element models were created for 10 individuals with patella alta (mean Insall-Salvati ratio of 1.34 ± 0.05). Input parameters for the finite-element models included subject-specific joint geometry, quadriceps muscle forces, and weightbearing patellofemoral joint kinematics. Virtual operations were conducted to simulate the two procedures. For distalization, the tibial tubercle and patella were displaced distally 4 mm to 20 mm in 4-mm increments based on the original model. At each level of distalization, the patella tendon was attached back to its original insertion to simulate the additional tenodesis procedure. Cartilage stress, contact area, and contact forces were quantified and compared between procedures and distalization levels. RESULTS: Distalization and distalization + tenodesis reduced patellofemoral joint stress compared with the baseline of 1.02 ± 0.11 MPa. Distalization led to lower cartilage stress than distalization + tenodesis, and the effect size was relatively large (0.88 ± 0.10 MPa vs 0.92 ± 0.10 MPa; mean difference, 0.04 MPa [95% CI, 0.02 MPa-0.05 MPa], p < 0.01; effect size of 1.64 [Cohen's d], with Insall-Salvati ratio decreased to 0.95). For both procedures, the trend of stress reduction plateaued when the Install-Salvati ratio approached 0.95. CONCLUSIONS: Cartilage stress appears lower using distalization as opposed to distalization + tenodesis in this finite-element analysis simulation. An Insall-Salvati ratio of 0.95 may be an ideal level for distalization; further distalization does not show additional benefits. CLINICAL RELEVANCE: This study suggests that distalization may result in less stress than distalization + tenodesis, therefore future clinical research might be preferentially directed toward evaluating isolated distalization procedures.

No Difference on Quantitative Magnetic Resonance Imaging in Patellofemoral Cartilage Composition Between Patients With Patellofemoral Pain and Healthy Controls.

BACKGROUND: Retropatellar cartilage damage has been suggested as an etiological factor for patellofemoral pain (PFP), a common knee condition among young and physically active individuals. To date, there is no conclusive evidence for an association between cartilage defects and PFP. Nowadays, advanced quantitative magnetic resonance imaging (MRI) techniques enable estimation of cartilage composition. PURPOSE: To investigate differences in patellofemoral cartilage composition between patients with PFP and healthy control subjects using quantitative MRI. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Patients with PFP and healthy control subjects underwent 3.0-T MRI including delayed gadolinium-enhanced MRI of cartilage and T1ρ and T2 mapping. Differences in relaxation times of patellofemoral cartilage were compared between groups by linear regression analyses, adjusted for age, body mass index, sex, sports participation, and time of image acquisition. RESULTS: This case-control study included 64 patients and 70 controls. The mean (±SD) age was 23.2 ± 6.4 years and the mean body mass index was 22.9 ± 3.4 kg/m(2); 56.7% were female. For delayed gadolinium-enhanced MRI of cartilage, the mean T1GD relaxation times of patellar (657.8 vs 669.4 ms) and femoral cartilage (661.6 vs 659.8 ms) did not significantly differ between patients and controls. In addition, no significant difference was found in mean T1ρ relaxation times of patellar (46.9 vs 46.0 ms) and femoral cartilage (50.8 vs 50.2 ms) and mean T2 relaxation times of patellar (33.2 vs 32.9 ms) and femoral cartilage (36.7 vs 36.6 ms) between patients and controls. Analysis of prespecified medial and lateral subregions within the patellofemoral cartilage also revealed no significant differences. CONCLUSION: There was no difference in composition of the patellofemoral cartilage, estimated with multiple quantitative MRI techniques, between patients with PFP and healthy control subjects. However, clinically relevant differences could not be ruled out for T1ρ in the adolescent population. Retropatellar cartilage damage has long been hypothesized as an important factor in the pathogenesis of PFP, but study findings suggest that diminished patellofemoral cartilage composition is not associated with PFP.

Patellar instability: CT and MRI measurements and their correlation with internal derangement findings.

PURPOSE: To test the inter-observer and inter-method reliability among the measures suggesting patellofemoral joint disorder on both CT and MRI in the same subject and find possible association with internal derangements of the patellofemoral joint on MRI. METHODS: Institutional review board approval was obtained with waiver of the informed consent in this HIPPA-compliant study. CT and MRI were evaluated in 32 knees in 32 respective subjects (10 men/22 women, mean age 38 ± 19 years). Three trained observers assessed tibial tuberosity-trochlear groove (TT-TG) distance, trochlear angle and trochlear depth on both CT and MRI. Intra-class correlation coefficient (ICC) was used to evaluate inter-observer and inter-method reliability. Two radiologists' consensus reading was used to evaluate their association with soft tissue abnormalities of the patellofemoral joint. Chi-square test was used to assess the statistical significance of the qualitative variables. RESULTS: There was an excellent inter-observer reliability (ICC for CT >0.89 and for MRI >0.90) and inter-method reliability (ICC >0.86) for all the quantitative measurements. There was a significant association between increased TT-TG distance value on MR imaging and lateral facet patellar cartilage abnormality and joint effusion (p < 0.05). CONCLUSION: Quantitative trochlear parameters can be reliably calculated on MRI, and an abnormal TT-TG distance is the most useful measurement among various static MR imaging parameters to correlate with patellar chondrosis and joint effusion. TT-TG distance should be reported in patellofemoral pain syndrome patients. LEVEL OF EVIDENCE: IV.

Atrophy of the Quadriceps Is Not Isolated to the Vastus Medialis Oblique in Individuals With Patellofemoral Pain.

STUDY DESIGN: Cross-sectional. Objectives To determine if quadriceps atrophy was present in people with patellofemoral pain (PFP), and whether the vastus medialis oblique (VMO) was selectively involved. BACKGROUND: Despite the lack of research investigating individual quadriceps muscle size in individuals with PFP, it has been suggested that selective atrophy of the VMO relative to the vastus lateralis could be associated with PFP. METHODS: The quadriceps muscle sizes of 35 participants with PFP (22 with unilateral and 13 with bilateral symptoms) and 35 asymptomatic control participants matched for age and sex were measured using real-time ultrasound. The thicknesses of the VMO, vastus lateralis, vastus medialis, rectus femoris, and vastus intermedius were measured. Paired-samples t tests were used to compare muscle thickness between limbs in those with unilateral PFP, and independent t tests were used to compare muscle thickness between groups with and without PFP. Results In those with unilateral PFP, the thickness of all portions of the quadriceps muscle was statistically smaller in the symptomatic compared to the asymptomatic limb: VMO (P = .038), vastus medialis (P<.001), vastus lateralis (P = .005), vastus intermedius (P = .013), and rectus femoris (P = .045). No difference was found in thickness of any of the portions of the quadriceps on the affected side of people with PFP compared to asymptomatic controls: VMO (P = .148), vastus medialis (P = .474), vastus lateralis (P = .122), vastus intermedius (P = .466), and rectus femoris (P = .508). CONCLUSION: Atrophy of all portions of the quadriceps muscles is present in the affected limb of people with unilateral PFP. There was no atrophy of the quadriceps in individuals with PFP compared to those without pathology. Selective atrophy of the VMO relative to the vastus lateralis was not identified in people with PFP.

Sagittal plane evaluation of patellofemoral movement in patellofemoral pain patients with no evidence of maltracking.

PURPOSE: The cause of abnormal patellar kinematics in patients with patellofemoral pain remains unclear. Many patients who develop patellofemoral pain symptoms do not exhibit evidence of maltracking. In these patients, sagittal plane evaluation of patellofemoral movement should be performed. METHODS: Knee radiographs were obtained for forty healthy volunteers and thirty patients at 0°, 30°, 60°, 90° and 120° of flexion in a standing weight-bearing position. The degree of active patellar movement was measured by a newly developed technique called "patellar motion angle". Three independent examiners sequentially performed all of the measurements under identical conditions. RESULTS: A significant decrease in the patellar motion angle was found during deep knee flexion from 90° to 120° in the patient group compared to the volunteer group (mean 18.5° ± 5.8° and 23.6° ± 6.2°, respectively) (P = 0.001). From 0° to 90° of knee flexion, no significant differences in the patellar motion angle were found between the two groups. CONCLUSION: Sagittal plane patellofemoral joint kinematics is an area of interest in the study of the mechanical factors associated with patellofemoral pain. This study demonstrated a decrease in patellar movement during deep knee bending activity in patients with patellofemoral pain. LEVEL OF EVIDENCE: Therapeutic study, Level II.

Shelf syndrome of the knee in elderly people: a report of three cases.

Shelf syndrome occurs mainly in younger people (particularly athletes) and rarely in elderly people. We report on 3 elderly patients with a medial synovial plica causing severe pain and locked knees. They had had no symptoms in their early or middle life. After removal of the shelf, the symptoms improved considerably. Although shelf syndrome is rare in the elderly, it should be suspected whenever severe pain and a locked knee are present.

Approach to the active patient with chronic anterior knee pain.

The diagnosis and management of chronic anterior knee pain in the active individual can be frustrating for both the patient and physician. Pain may be a result of a single traumatic event or, more commonly, repetitive overuse. "Anterior knee pain," "patellofemoral pain syndrome," and "chondromalacia" are terms that are often used interchangeably to describe multiple conditions that occur in the same anatomic region but that can have significantly different etiologies. Potential pain sources include connective or soft tissue irritation, intra-articular cartilage damage, mechanical irritation, nerve-mediated abnormalities, systemic conditions, or psychosocial issues. Patients with anterior knee pain often report pain during weightbearing activities that involve significant knee flexion, such as squatting, running, jumping, and walking up stairs. A detailed history and thorough physical examination can improve the differential diagnosis. Plain radiographs (anteroposterior, anteroposterior flexion, lateral, and axial views) can be ordered in severe or recalcitrant cases. Treatment is typically nonoperative and includes activity modification, nonsteroidal anti-inflammatory drugs, supervised physical therapy, orthotics, and footwear adjustment. Patients should be informed that it may take several months for symptoms to resolve. It is important for patients to be aware of and avoid aggravating activities that can cause symptom recurrence. Patients who are unresponsive to conservative treatment, or those who have an underlying systemic condition, should be referred to an orthopedic surgeon or an appropriate medical specialist.

Diagnosis and treatment of excessive lateral pressure syndrome of the patellofemoral joint caused by military training.

OBJECTIVE: To investigate the diagnosis and surgical treatment of excessive lateral pressure syndrome of the patellofemoral joint caused by military training. METHODS: Fifteen patients (patient group) and 18 healthy volunteers (control group) were involved in this retrospective study. Radiographs of the knee joints of all patients and volunteers were taken. The bone architecture was assessed, the trochlear angle, coincidence angle and patellofemoral joint index measured in both groups, and the resulting data compared. All 15 patients (17 knees) were treated by lateral collateral retinaculum release. Pre- and post-operative pain was evaluated with a visual analog scale (VAS). RESULTS: The differences between the two groups in coincidence angle (patient group: 7.67°± 5.81°; control group: -2.2°±-2.71°) and patellofemoral joint index (patient group: 2.49 ± 1.40; control group: 1.25 ± 0.15) were statistically significant. Subchondral bone sclerosis and osteophytosis in the patellofemoral joint were more pronounced in the patient group than in the control group. The VAS was higher preoperatively (7.06 ± 0.85) than postoperatively (6 months postoperatively: 3.87 ± 0.24; 1 year postoperatively: 3.01 ± 0.17), and the differences between preoperative and postoperative were statistically significant. CONCLUSIONS: Apart from the case history, typical symptoms and physical signs, X-ray examination is the most basic way to diagnose excessive lateral pressure syndrome of the patellofemoral joint, and the patellofemoral joint index is the most reliable for diagnosis. Lateral collateral retinaculum release with a small-incision is an effective treatment for this disease.

The EOS imaging system for understanding a patellofemoral disorder following THR.

An aspect of patellofemoral syndrome secondary to total hip replacement (THR) is mainly suggestive of a problem of femoral implant torsion. We here present the first reported case of patellofemoral syndrome secondary to THR relating to limb-length discrepancy, with no abnormality of femoral torsion. The pelvis adapted to the length inequality by axial rotation rather than frontal tilt, and this went undetected on standard X-ray and CT-scan. 3D imaging in upright posture on the EOS system enabled the situation to be clearly described and analyzed, and adapted surgical correction to be indicated.

Complications of posterior cruciate ligament surgery.

In addition to standard risks associated with all orthopedic surgical procedures, posterior cruciate ligament (PCL) reconstruction poses some relatively unique potential complications. These complications arise from a combination of several factors: the relative infrequency of PCL injuries, the lack of knowledge and experience in treating them, the proximity of neurovascular structures to the PCL, and the technically demanding nature of reconstructive procedures. This article discusses the anatomy, pathogenesis, and prevention of intraoperative and postoperative complications of PCL surgery including neurovascular injury, osteonecrosis, fracture, motion loss, and persistent laxity.

Proximal tibial derotation osteotomy for torsional tibial deformities generating patello-femoral disorders.

INTRODUCTION: Torsional abnormalities of the leg may cause instability and pain in the patellofemoral joint. Although derotation osteotomies seem logical to address these conditions, there are very few surgical results reported in the literature. HYPOTHESIS: Isolated tibial derotation osteotomies relieve patellofemoral pain and instability even in the event of combined femoral and tibial torsion abnormalities. AIM: Test this hypothesis in a retrospective and continuous series of thirty-six tibial derotation osteotomies and define the factors of success and failure. PATIENTS AND METHODS: Thirty-six derotation osteotomies of the proximal tibial metaphysis were performed between 1995 and 2006 in 29 patients (five men and 24 women, an average of 26.5 years old±7.4 (18-44)) followed-up for a mean 4.7 years. There was confirmed patellar instability in five knees, and patellofemoral pain without instability in 31. A proximal metaphyseal osteotomy was performed to correct excessive external tibial rotation as well as to recenter the tibial tubercle after anterior tibial cortex elevation. All patients were followed-up and the clinical data were analysed according to criteria from the Lille score [specifically designed for patellofemoral joints (100 point score)] and the IKS score. All patients had a preoperative radiological evaluation [(including measurement of torsion abnormalities in 32 cases by computed tomodensitometry (CT scan))]. The mean preoperative external tibial torsion measured on CT scan was 36.2°±9.48 (26-51°) and the mean femoral anteversion was 19.4°±9.5 (8-36°). RESULTS: Twenty-seven patients (94%) were satisfied or very satisfied. The Lille score increased from 54.8±16.9 (30-92) preoperatively to 85.2±14.2 (36-100) at follow-up. The mean IKS knee scores and function increased from 56±14.8 (45-94) to 94±12.1 (60-100) and from 71±18.4 (30-100)-96±11.9 (50-100). Patellofemoral dislocations did not occur in any of the five cases with instability. Mean derotation was 25° measured with a mean tibial torsion measured clinically at follow-up 8.6°±7.2 (0-30). Two reoperations were necessary, (one knee manipulation under general anesthesia, and in another the fibular fibrous arch had to be released). One case of regressive palsy of the common fibular nerve was observed. Union of the osteotomy was obtained in all patients. DISCUSSION: This series is one of the largest series published to date. Isolated medialization of the anterior tibial tubercle only partially corrects these morphological abnormalities. In cases of associated excessive femoral anteversion we recommend surgery to the tibia alone because results were comparable in groups with and without excessive anteversion of the femoral neck. LEVEL OF EVIDENCE: level IV. Retrospective study.

The effects of quadriceps contraction on different patellofemoral alignment subtypes: an axial computed tomography study.

STUDY DESIGN: Controlled laboratory study. BACKGROUND: The effect of quadriceps contraction on patellar alignment in patients with patellofemoral pain syndrome (PFPS) is debated and may vary based on patellar alignment subtypes measured with the quadriceps relaxed. OBJECTIVES: To determine if the effects of quadriceps contraction on patellar alignment differs (1) with respect to patellar alignment subtype in individuals with PFPS and (2) between symptomatic and asymptomatic knees in individuals with unilateral PFPS. METHODS AND MEASURES: Seventy-eight individuals, 47 with bilateral and 31 with unilateral PFPS, participated in the study. On axial computed tomography images with the knee in extension with quadriceps relaxed as well as contracted, patellar lateral condyle index (PLCI) and patellar tilt angle (PTA) were measured and analyzed. Based on the median PLCI and PTA alignment values measured with quadriceps relaxed for the 78 subjects, 4 subgroups of subjects were created: type 1, laterally displaced; type 2, laterally displaced and tilted; type 3, laterally tilted; and type 4, neither. RESULTS: Quadriceps contraction caused an increase in PLCI in all patellar alignment types (P<.01), with no difference in the magnitude of the increase between types (P>.05). PTA decreased with quadriceps contraction in the subjects with the type 3 initial patellar alignment (P<.01), with a significant difference in the change in patellar alignment between the subjects with type 3 and type 1 initial patellar alignment (P=.004). For the 31 subjects with unilateral PFPS, quadriceps contraction caused a similar change in PLCI and PTA in both the symptomatic and asymptomatic knees. CONCLUSIONS: The initial position of the patella with the quadriceps relaxed did not influence the change in PLCI with quadriceps contraction. For the 31 subjects with PFPS, there was no difference in initial alignment as well as in change of alignment with quadriceps contraction between symptomatic and asymptomatic knees.