Extensor Mechanism Malalignment Research Articles

Quadriceps tendon malalignment is an independent anatomical deformity which is the primary abnormality associated with lateral facet patellofemoral joint osteoarthritis.

The purposes of this study are to, firstly, develop techniques to accurately identify extensor mechanism malalignment by measuring the alignment of the quadriceps tendon (QTA) with computerized tomography (CT) scans. Secondly, to investigate correlations between QTA and lower limb bony anatomical variations within a representative normal population. Lastly, to evaluate the clinical significance of QTA by establishing its potential connection with lateral facet patellofemoral joint osteoarthritis (LFPFJOA). CT scans were orientated to a mechanical axis reference frame and three techniques developed to measure the alignment of the quadriceps tendon. Multiple measurement of bony alignment from the hip to the ankle were performed on each scan. A series of 110 cadaveric CT scans were measured to determine normal values, reproducibility, and correlations with bony anatomy. Secondly, a comparison between 2 groups of 25 patients, 1 group with LFPFJOA and 1 group with isolated medial OA and no LFPFJOA. From the cadaveric study, it was determined that the alignment of the quadriceps tendon is on average 4.3° (SD 3.9) varus and the apex of the tendon is 9.1mm (SD 7.7mm) lateral to the trochlear groove and externally rotated 1.9° (SD 12.4°) from the centre of the femoral shaft. There was no association between the quadriceps tendon alignment and any other bony measurements including tibial tubercle trochlear groove distance (TTTG), coronal alignment, trochlear groove alignment and femoral neck anteversion. A lateralized QTA was significantly associated with LFPFJOA. QTA in the LFPFJOA group was 9.6° varus (SD 2.8°), 21.3mm (SD 6.6) lateralised and 17.3° ER (SD 11°) compared to 5.5° (SD 2.3°), 10.7mm (SD 4.9) and 3.3° (SD 7.2°), respectively, in the control group (p < 0.001). A significant association with LFPFJOA was also found for TTTG (17.2mm (SD 5.7) vs 12.1mm (SD 4.3), p < 0.01). Logistic regression analysis confirmed the QTA as having the stronger association with LFPFJOA than TTTG (AUC 0.87 to 0.92 for QTA vs 0.79 for TTTG). These studies have confirmed the ability to accurately determine QTA on CT scans. The normal values indicate that the QTA is highly variable and unrelated to bony anatomy. The comparative study has determined that QTA is clinically relevant and a lateralised QTA is the dominant predictor of severe LFPFJOA. This deformity should be considered when assessing patella maltracking associated with patella osteoarthritis, patella instability and arthroplasty. III (retrospective cohort study).

Combined MPFL reconstruction and tibial tubercle osteotomy for patellar instability: A retrospective review of 23 patients

The primary objective of this retrospective study is to compare patient outcomes following a combined approach (MPFL reconstruction and TTT) to outcomes reported in the literature by patients who required either only an isolated TTT procedure to treat pathologic lateral patellar instability or isolated MPFL reconstruction to treat patellar dislocation due to MPFL insufficiency. Twenty-three patients (74%) were available for follow-up and are included in our analysis. MPFL reconstruction combined with TTT has a high rate of success for patients presenting with patellar instability and extensor mechanism mal-alignment. The risk of recurrence with this technique was low (4.3%).

Osteotomies in Patello-Femoral Instabilities.

Patellar instability is defined by clinical and radiologic criteria. The surgical treatment is aimed at restoring the congruence of the patellofemoral articulation and correcting extensor mechanism malalignment, to prevent recurrence of dislocation. The standard soft-tissue procedures are lateral release and vastus medialis advancement and medial patello femoral ligament plasty. Bony procedures are frequently performed in addition to soft-tissue surgery, to realign the extensor mechanism by means of tibial tubercle medialization, or to correct the patellar index in patella alta. In a smaller number of patients, the trochlea may be reshaped, by elevating the lateral trochlear facet or by lowering the floor of the sulcus. The morphologic abnormalities encountered are studied and quantified in the light of preoperative investigations (conventional radiographs and computed tomography), and addressed at surgery using the technique or techniques most appropriate for the management of the individual patient's pattern.

Correction of Patellofemoral Malalignment With Patellofemoral Arthroplasty

BackgroundThe goal of patellofemoral arthroplasty (PFA) is to replace damaged cartilage and correct underlying deformities to reduce pain and prevent maltracking. We aimed to determine how PFA modifies patellar height, tilt, and tibial tuberosity-trochlear groove (TT-TG) distance. The hypothesis was that PFA would correct trochlear dysplasia or extensor mechanism malalignment. MethodsThe authors prospectively studied a series of 16 patients (13 women and 3 men) aged 64.9 ± 16.3 years (range 41-86 years) who received PFA. All knees were assessed preoperatively and 6 months postoperatively using frontal, lateral, and “skyline” x-rays, and computed tomography scans to calculate patellar tilt, patellar height, and TT-TG distance. ResultsThe interobserver agreement was excellent for all parameters (intraclass correlation coefficient >0.95). Preoperatively, the median patellar tilt without quadriceps contraction (QC) was 17.5° (range 5.3°-33.4°) and with QC was 19.8° (range 0°-52.0°). The median Caton-Deschamps index was 0.91 (range 0.80-1.22) and TT-TG distance was 14.5 mm (range 4.0-22.0 mm). Postoperatively, the median patellar tilt without QC was 0.3° (range −15.3° to 9.5°) and with QC was 6.1° (range −11.5° to 13.3°). The median Caton-Deschamps index was 1.11 (range 0.81-1.20) and TT-TG distance was 10.1 mm (range 1.8-13.8 mm). ConclusionThe present study demonstrates that beyond replacing arthritic cartilage, trochlear-cutting PFA improves patellofemoral congruence by correcting trochlear dysplasia and standardizing radiological measurements as patellar tilt and TT-TG. The association of lateral patellar facetectomy improves patellar tracking by reducing the patellar tilt.

Patellar Tendon-Trochlear Groove Angle Measurement: A New Method for Patellofemoral Rotational Analyses.

Background:The tibial tubercle–trochlear groove (TT-TG) is used as the gold standard for patellofemoral malalignment.Purpose:To assess 3 patellar tendon–trochlear groove (PT-TG) angle measurement techniques and the PT-TG distance measurement (tendinous cartilaginous TT-TG) as predictors of patellar instability.Study Design:Cohort study (diagnosis); Level of evidence, 3.Methods:Three PT-TG angle measurements and the PT-TG distance were measured in 82 participants with patellar instability and 100 controls using magnetic resonance imaging (MRI). Measurement landmarks were the line tangent to the posterior femoral condyles, the deepest point of the trochlea, the transepicondylar line, and the patellar tendon center. All measurements were recorded once by 1 examiner, and the measurements were recorded twice by 2 examiners in a random group of 100 knees. Mean values and standard deviations (SDs) were obtained. Normality cutoff values were defined as 2 and 3 SDs above the mean in the control group. The sensitivity, specificity, and positive likelihood ratio (LR+) were calculated. Inter- and intrarater reliability were assessed based on the intraclass correlation coefficient (ICC).Results:The measurements from the patellar instability and control groups, respectively, for angle 1 (16.4° and 8.4°), angle 2 (31° and 15.6°), angle 3 (30.8° and 15.7°), PT-TG distance (14.5 and 8.4 mm), and patellar tilt (21.1° and 7.5°) were significantly different (P < .05). The angle measurements showed greater sensitivity, specificity, and LR+ than the PT-TG distance. Inter- and intrarater ICC values were >0.95 for all measurements.Conclusion:The PT-TG angle and the PT-TG distance are reliable and are different between the patellar instability and control groups. PT-TG angles are more closely associated with patellar instability than PT-TG distance.Clinical Relevance:PT-TG angle measurements show high reliability and association with patellar instability and can aid in the assessment of extensor mechanism malalignment. A more sensitive and specific evaluation of extensor mechanism malalignment can improve patient care by preventing both redislocation and abnormal tracking of overlooked malalignment and complications of unnecessary tibial tuberosity medialization.

Combined MPFL Reconstruction and Tibial Tubercle Transfer for Patellofemoral Instability

Both medial patellofemoral ligament (MPFL) reconstruction and Tibial Tubercle Transfer (TTT) are established procedures for patients suffering from patellofemoral instability. In patients with a heightened Q angle, MPFL reconstruction performed in isolation may increase contact forces across the patellofemoral joint and not restore medial patellar tracking. The purpose of the present study is to determine the outcomes of combined MPFL and TTT for patellar instability with elevated Q angle. 32 patients were identified from a surgical database of having received combined MPFL reconstruction and TTT from 2008-2010. All patients were treated by one of four fellowship trained sports medicine physicians utilizing an identical surgical technique. Minimum follow-up was 24 months for inclusion in the study. Patients were evaluated for recurrence of instability, complications, and functional outcome (Kujala and Lysholm outcome scores). Of the 32 patients (35 knees) that underwent this procedure during the time period studied, 20 patients (22 knees) met our inclusion criteria and are included in this analysis. The average length of follow-up was 39 months (range 28 to 50). There were 1 male(s) and 19 females in this analysis, with an average age of 25. The average Kujala and Lysholm scores at final follow-up were 81.09 and 75.41, respectively. One patient(s) (5.0%) sustained a recurrence of dislocation. There were 5 (25.0%) patients with complications: wound complications requiring repeat surgery (3/15.0%), stiffness (2/10.0%), chondroplasty (1/5.0%) and lysis of adhesions (1/5.0%). There were no infections in this series. 4 (16.7%) patients required a secondary procedure to remove painful hardware. MPFL reconstruction combined with tibial tubercle transfer has a high rate of success for patients presenting with patellar instability and extensor mechanism mal-alignment. The risk of recurrence with this technique was low (5.0%), and the risk of complications is equivalent to other techniques previously reported in the literature.

Patellar chondral defects: a review of a challenging entity

The aim of this study was to perform a review of the management of patellar cartilage defects, identify prognostic factors for better clinical outcomes, and propose a treatment algorithm of this challenging entity. We conducted a review of multiple databases, evaluating the clinical outcomes after patellar cartilage lesion treatment. Because of the heterogeneity of data, a meta-analysis could not be performed. Twelve studies were identified for inclusion. Based on the clinical outcomes of these studies, a treatment algorithm was proposed. The clinical outcomes after patellar cartilage defects repair depend on the location and size of the articular defect, the age of the patient, the successful reconstruction of the patellar ridge, the repair of extensor mechanism malalignment, and the coexistence of chondromalacia. The optimal treatment for cartilaginous defects of the patella is still elusive. More prospective studies are needed, in order to identify which techniques are cost-effective especially on a long-term basis.

Evaluation of the Modified Elmslie-Trillat Procedure for Patellofemoral Dysfunction

The goal of this study was to evaluate the Elmslie-Trillat procedure for recurrent patellar dislocation, patellofemoral pain (with extensor mechanism malalignment), or a combination of both. Thirty-two patients underwent the modified Elmslie-Trillat procedure, consisting of a lateral retinacular release and medialization of the tibial tuberosity for recurrent patellar dislocation, patellofemoral pain, or both. Twenty-nine of 32 patients were available for follow-up. All patients were evaluated clinically and radiologically. Subjective scores were evaluated using the Cox grading system and objective scores using Fulkerson's functional knee score. Average patient age was 33 years. Mean follow-up was 45 months. Subjectively, using the Cox grading system, 10 patients (34%) had an excellent result, 8 (28%) had a good result, 8 (28%) had a fair result, and 3 (10%) had a poor result. All patients with patella dislocation had an excellent or good subjective result, while only 3 patients (34%) with the primary symptom of patellofemoral pain with extensor mechanism malalignment and 4 patients (44%) with a combination of both symptoms had a good or excellent result. Mean Fulkerson's functional knee score was excellent for patients with dislocation only, and fair for those with only pain or both pain and dislocation. The congruence angle was corrected in all patients with this technique. There were no further dislocations in our series. Two patients required hardware removal. The Elmslie-Trillat procedure is a good surgical option for treatment of recurrent patella instability following failed conservative therapy. However, the results are not as favorable for patients with patellofemoral pain without instability.

Ultrasound Diagnosis for Preventing Knee Injuries in Cuban High-Performance Athletes

Diagnostic evaluation of the musculoskeletal system has traditionally been based on medical history, physical examination, and x-rays (techniques that provide limited information), and more re- cently on computerized axial tomography and magnetic resonance imaging (both very expensive). Ultrasound, a non-invasive and less expensive method, has become an indispensable tool for diagnos- ing overuse sports injuries. The Imaging Department at the Cuban Sports Medicine Institute (abbreviated in Spanish as IMD) developed a preventive ultrasound diagnostic imaging method and has applied it for the last 15 years as part of the IMD's medical management of high-performance athletes. Objectives Identify normal ultrasound patterns for knee structures and extensor mechanism alignment, and perform ultrasound imag- ing of the knee on asymptomatic, high-performance athletes to detect alterations and endogenous predisposing factors to overuse sports injuries as a basis for adopting preventive action. Methods A descriptive cross-sectional study was conducted of 300 non-athletes (control) and 100 Cuban Olympic athletes (preselected for the 2000 Olympic Games in Sydney, Australia). The IMD's Preven- tive Ultrasound Diagnostic Imaging Method was used to perform static and dynamic ultrasound examinations of both knees of all subjects (800 knees total) to determine normal patterns, detect structural alter- ations in the knee, and determine extensor mechanism malalignment. For the latter, Anillo's Patellofemoral Congruence Ultrasound Method was applied to determine the degree of patellar lateralization (RAB angle). Data was processed using descriptive statistics. To compare the ratio of ultrasound knee alterations detected, the Chi-square test was used. Percentiles were calculated based on data from the 600 non-athlete knees and were processed using the SPSS statistics ap- plication. Results Of the 100 athletes studied, 57 were found to have subclinical alterations in one or both knees, distributed as follows: synovitis (30), extensor mechanism malalignment (26), infrapatellar fat pad distortion (15), meniscal echostructure modification (14), ligament echostructure alteration (11), and articular cartilage alteration (7). Analysis of the control group findings established that RAB angle values greater than 13° for both sexes suggest excessive patellar lateralization with respect to the axial axis of the femur, potentially an endogenous risk factor favoring injury. Conclusions Preventive ultrasound diagnostic imaging of the knee, performed using IMD's ultrasound scanning methodology and incorpo- rating the normal ultrasound patterns described in this study, enables diagnosis of distortions in the articular and periarticular echostructure prior to the onset of clinical symptoms, as well as observation of en- dogenous predisposing factors linked to overuse sports injuries. As a result, appropriate measures can be adopted to prevent such injuries and to tailor medical management of high-performance athletes.

Instabilités de la rotule: histoire, étiologie et indications pour le traitement. Le menu à la carte de 2008

Patellar instability is defined by clinical and radiological criteria. There are three populations, known as Objective Patellar Instability, Potential Patellar Instability, Patellar Painful Syndrome. Surgical treatment is aimed at restoring the congruence of the patello-femoral articulation and correcting extensor mechanism malalignment, to prevent recurrence of dislocation. The standard soft-tissue procedures are lateral release and vastus medialis advancement and patello-femoral medial ligament plasty. Bony procedures are frequently performed in addition to soft-tissue surgery, to realign the extensor mechanism by means of tibial tubercle medialization, or to correct the patellar index in patella alta. In a smaller number of patients, the trochlea may be reshaped, by elevating the lateral trochlear facet or by lowering the floor of the sulcus. The morphological abnormalities encountered are studied and quantified in the light of preoperative investigations (conventional radiographs and computed tomography), and addressed at surgery using the technique or techniques most appropriate for the management of the individual patient’s pattern.

Osteotomies in Patello-Femoral Instabilities

Patellar instability is defined by clinical and radiologic criteria. The surgical treatment is aimed at restoring the congruence of the patellofemoral articulation and correcting extensor mechanism malalignment, to prevent recurrence of dislocation. The standard soft-tissue procedures are lateral release and vastus medialis advancement and medial patello femoral ligament plasty. Bony procedures are frequently performed in addition to soft-tissue surgery, to realign the extensor mechanism by means of tibial tubercle medialization, or to correct the patellar index in patella alta. In a smaller number of patients, the trochlea may be reshaped, by elevating the lateral trochlear facet or by lowering the floor of the sulcus. The morphologic abnormalities encountered are studied and quantified in the light of preoperative investigations (conventional radiographs and computed tomography), and addressed at surgery using the technique or techniques most appropriate for the management of the individual patient's pattern.

(iv) Patellofemoral dysfunction—Extensor mechanism malalignment

Anterior knee pain has many causes. When it arises from the knee extensor mechanism, those with normal alignment must be distinguished from those with malalignment. Patellar dislocation is at one extreme of a spectrum of disorders that are due to malalignment of the extensor mechanism of the knee. This article discusses important aspects of extensor mechanism malalignment and a logical approach to operative treatment for patients with failed conservative therapy. Anterior knee pain has many causes. When it arises from the knee extensor mechanism, those with normal alignment must be distinguished from those with malalignment. Patellar dislocation is at one extreme of a spectrum of disorders that are due to malalignment of the extensor mechanism of the knee. This article discusses important aspects of extensor mechanism malalignment and a logical approach to operative treatment for patients with failed conservative therapy.

Formal Extensor Mechanism Reconstruction

The clinical syndrome of extensor mechanism malalignment can either be primary or secondary. The distinguishing feature of extensor mechanism malalignment is passive patellar hypermobility at 30 degrees of flexion, which yields apprehension. Formal extensor mechanism reconstruction requires multiple steps, which are described along with variations.