Presence Of Trochlear Dysplasia Research Articles

Outcomes of Surgical Interventions for Patellofemoral Instability in the Presence of Trochlear Dysplasia: A Systematic Review and Meta-analysis

Background: Patellar instability is frequently encountered by orthopaedic surgeons. One of the major risk factors of this condition is underlying trochlear dysplasia (TD). Recent trends have indicated the use of multiple procedures to correct patellar instability under these conditions. Medial patellofemoral ligament reconstruction (MPFLR) and trochleoplasty (TP) are surgical strategies that have demonstrated successful outcomes. However, it is unclear whether isolated MPFLR suffices for patellar instability in the presence of severe TD. Furthermore, the need for TP or a combined approach, considering its invasiveness and technical demands, to achieve better clinical outcomes and patellofemoral stability remains uncertain. Purpose: To compare the outcomes of 3 surgical interventions for addressing patellar instability due to TD: MPFLR, TP, and combined MPFLR and TP. Study Design: Systematic review and meta-analysis; Level of evidence, 4. Methods: Studies reporting the clinical outcomes of MPFLR, TP, and both in combination, regardless of additional procedures, were identified using the MEDLINE, PubMed, Embase, Scopus, Cochrane Library, Cochrane Central Register of Controlled Trials, and Cumulative Index to Nursing and Allied Health Literature databases. An important inclusion criterion was that studies should include the mean preoperative and postoperative Kujala scores and any complications. A random-effects model was used for the meta-analysis. Results: Overall, 30 studies were included: 10 describing the outcomes of TP, 13 describing the outcomes of MPFLR, and 7 describing the outcomes of combined TP and MPFLR. Furthermore, 1457 patients (1571 knees) were evaluated with a mean follow-up of 42.4 ± 32.8 months. No statistically significant differences were found between the 3 methods regarding the mean difference using the Kujala score. However, combined MPFLR and TP had the highest weighted mean difference compared with the other 2 procedures (28.5 points; P < .001). Evidential analysis revealed a robust log-likelihood ratio ( S = 3.2) supporting the superiority of the combined procedure when comparing this mean and the weighted grand mean of 23.7. The redislocation rate after patellar stabilization remained minimal, irrespective of the surgical procedure (mean, 0.7%). However, the rate of residual patellar instability was the highest in the TP group (mean, 13.5%). Conclusion: This study found no statistically significant difference between the outcomes of the 3 procedures. However, the combined approach of MPFLR and TP was associated with the most promising clinical outcomes and a low redislocation rate in patients with varying severities of TD.

The prevalence of radiographic trochlear dysplasia in patients with patellar fractures

PurposeTrochlear dysplasia is found in 3.2% (95% confidence interval (CI) 1.2–6.7) of the general population and linked to patellar instability and anterior cruciate ligament (ACL) injuries. The purpose of this study was to evaluate the prevalence of radiographic trochlear dysplasia in patients with patellar fractures. Secondary outcome was to evaluate the prevalence of trochlear dysplasia in different type of patellar fracture.MethodsAll consecutive 18-year-old or older patients treated in a level-1 trauma center for patellar fracture between 2003 and 2016 were retrospectively evaluated. Trochlear dysplasia was assessed according to Dejour’s classification on a strict lateral knee x-ray. Patellar fractures were analyzed on AP, lateral and axial knee x-rays and classified on pattern and displacement. Patellar dislocation at time of injury was recorded.ResultsOut of 482 patellar fractures, a strict lateral knee x-ray was found in 166 cases (50.6% women, mean age 56years +/-21, 51% right knee). Nineteen cases had trochlear dysplasia (11.5%, 95% CI 6.9–17.9): 10 high-grade trochlear dysplasia meaning type B, C and D (6.0%, 95% CI 2.4–9.7%); 15 without dislocation (9.3%, 95% CI 5.2–15.3). Patellar fracture distribution showed 17 transverse non-displaced (10.2%), 38 transverse displaced (22.9%), 15 avulsion (9%), 27 multifragmented non-displaced (16.3%), 56 multi-fragmented displaced (33.7%), 7 vertical (4.2%) and 6 osteochondral (3.6%) fractures. Four dislocations were recorded, all had osteochondral fractures and trochlear dysplasia. When considering patellar fractures with dislocation, the incidence of osteochondral lesions was significantly higher in patients with trochlear dysplasia (p < 0.001). This is not true for any other type of patellar fracture (p = 0.138).ConclusionsThis study suggests that there is a significant prevalence of trochlear dysplasia in patients with patellar fractures. This study also suggests that the pattern of patellar fracture is not influenced by the presence of trochlear dysplasia, except for osteochondral fractures associated with patello-femoral dislocations.

Incidence of Early Adverse Events After Tibial Tubercle Osteotomy.

Tibial tubercle osteotomy (TTO) is a commonly utilized surgical procedure for the treatment of patellofemoral instability. Although midterm and long-term outcomes are known, perioperative complications have not been consistently reported. To identify the incidence and predictors of adverse events in the first 90-day perioperative period after TTO. Case series; Level of evidence, 4. Patients undergoing primary TTO between January 1, 2010, and December 31, 2019, were included. Readmissions in the first 90 days after surgery were collected, and data were collected for the following variables: age, sex, smoking status, body mass index, laterality, preoperative diagnosis, presence of trochlear dysplasia, tourniquet use, TTO procedure, tibial tubercle distalization, trochleoplasty, chondral procedure, number of screws, and use of an epidural catheter. Predictors of readmission for any reason were identified using multivariable logistic regression analysis. A total of 345 TTO procedures were included in the final analysis. The incidence of readmissions for any reason was 20.6% (71/345). The most common reason for readmission was postoperative pain (26/345 [7.5%]), followed by wound complications (19/345 [5.5%]) and epidural catheter-related complications (overall: 16/345 [4.6%]; specific: 16/167 [9.6%]. The incidence of major complications was 2.0% (7/345). The number of patients with each major complication was as follows: 1 for deep vein thrombosis, 2 for pulmonary embolism, 1 for septic arthritis, 1 for tibial tubercle fracture, and 2 for loss of fixation. Female sex and smoking were associated with readmission for pain. The incidence of major complications after TTO was very low (2.0%), but 20.6% of cases required readmission, primarily for an indwelling epidural catheter (3.5%) and postoperative pain (7.5%). Concomitant soft tissue procedures and the number of screws were associated with readmission after TTO. Utilizing individualized postoperative pain management and preoperative discussions about expected pain may help to avoid readmission for pain after TTO.

Posterior tibial slope, notch width index and tibial tubercle to trochlear groove distance contribute to development of mucoid degeneration of the anterior cruciate ligament: a systematic review.

To determine what knee morphological factors are associated with the development of mucoid degeneration of the anterior cruciate ligament (ACL). Three databases MEDLINE, PubMed and EMBASE were searched from inception to January 29th, 2023 for literature outlining knee morphological factors that potentially lead to the development of mucoid degeneration of the ACL. The authors adhered to the PRISMA and R-AMSTAR guidelines as well as the Cochrane Handbook for Systematic Reviews of Interventions. Data on receiver operating characteristic (ROC) curve parameters such as area under the curve (AUC), sensitivity and specificity, odds ratios, as well as p values for comparisons of values between mucoid degeneration of the ACL and control patients were recorded. The Methodological Index for Non-Randomized Studies(MINORS) score was used for all studies to perform a quality assessment of included studies. A total of 7 studies comprising 1326 patients (1330 knees) were included in this review. Four studies reported a significant association between increasing posterior tibial slope angles and mucoid degeneration of the ACL presence, with one study specifying that posterolateral tibial slope had a greater association than posteromedial tibial slope. Two studies reported a significant association between lower notch width index values and mucoid degeneration of the ACL presence. One study found that the presence of trochlear dysplasia was correlated with mucoid degeneration of the ACL and two studies found that increased tibial tuberosity-trochlear groove distance (TT-TG) was associated with mucoid degeneration of the ACL. Increased posterior tibial slope, decreased notch width index, and elevated TT-TG and trochlear dysplasia were associated with the presence of mucoid degeneration of the ACL. Information from this review can aid surgeons in understanding what morphological features predispose their patients to the development of mucoid degeneration of the ACL. Identifying what features predispose patients to mucoid degeneration of the ACL can help determine if regular screening or preventative strategies are necessary. Level III.

Arthroscopic Anatomical Double-Bundle Medial Patellofemoral Complex Reconstruction Improves Clinical Outcomes in Treating Recurrent Patellar Dislocation Despite Trochlear Dysplasia, Elevated Tibial Tubercle–Trochlear Groove Distance, and Patellar Alta

To evaluate the clinical outcomes of arthroscopically assisted double-bundle medial patellofemoral complex reconstruction (MPFC-R). A retrospective review was carried out among adult patients who experienced at least 2 patellar dislocations and underwent primary arthroscopically assisted MPFC-R between January 2014 and November 2019. Dejour classification, tibial tubercle-trochlear groove (TT-TG) distance, and patellar height (with Insall-Salvati index) were measured. Pre- and postoperative patellar tilt were compared. Information on outcome scores, ability to return to sports, postoperative recurrent dislocations, and complications was recorded. A total of 42 MPFC-Rs in 39 patients were included. Mean age at surgery was 22.2 ± 7.6 years; 69.2% of patients were female. Mean follow-up was 47.3 ± 20.2 months. Seventy-four percent of cases had Dejour B (19.0%), C (33.3%), and D (21.4%) trochlear dysplasia; mean TT-TG distance was 19.6 ± 3.5 mm, and mean Insall-Salvati index was 1.21 ± 0.17. Mean patellar tilt decreased from 27.6 ± 11.6° to 9.4 ± 6.5° (P < .001). All patients had statistically significant (P < .001) improvement in mean International Knee Documentation Committee (IKDC) (44.9 ± 18.2 to 87.5 ± 6.9), Lysholm (61.4 ± 16.6 to 94.1 ± 6.4), Kujala (56.0 ± 16.8 to 92.9 ± 5.3), and Tegner score (2.7 ± 1.3 to 4.6 ± 1.4). The majority of patients (96.9%) returned to sports, with 90.3% returning to the same or greater level of activity. No postoperative dislocations or subluxations were reported. Arthroscopically assisted double-bundle MPFC-R is a promising procedure to treat recurrent patellar instability at 2- to 7-year mid-term follow-up, despite the presence of trochlear dysplasia, elevated TT-TG distance and patellar alta. The improvement of IKDC score exceeded the minimal clinically important difference in 95.2% patients, and 66.7% surpassed the patient acceptable symptomatic state based on postoperative IKDC score with no redislocations being reported at latest follow-up. Level IV, case series, retrospective.

MPFL reconstruction and tibial tuberosity transposition in patients with patellar instability: May it troubleshots also trochlear dysplasia?

PurposeThis study aimed to highlight short- and medium-term outcomes of combined medial patello-femoral ligament (MPFL) reconstruction and anterior tibial tuberosity (ATT) transposition surgery in patients with recurrent patellar instability and different degrees of trochlear dysplasia.MethodsBetween January 2014 and May 2019, 25 patients with patellar instability underwent a surgical procedure combining the lowering/transposition of the ATT and the MPFL reconstruction. Each patient were preoperative assessed by Kujala score, International Knee Documentation Committee (IKDC), Tegner activity level scale. The assessment of instability predisposing factors was carried out with patellar height, tibial tuberosity-trochlear groove (TT-TG) distance, trochlear dysplasia, sulcus angle, patellar tilt and MPFL injuries. Functional outcomes were evaluated with Kujala, IKDC and Tegner scores at 3, 6 and 12 months after surgery.ResultsThe average age of the patients was 20 years (range 13–43 years). Pre- operative Caton–Deschamps index was pathological in 10 (40%). Sulcus angle was elevated in 13 patients (52%) and TT-TG distance was irregular in 17 patients (68%). Trochlear dysplasia was present in 13 patients (9 type A, 3 type B, 1 type C according to Dejour’s Classification). No re-dislocation occurred during the follow-up. There was a significant increase in the Kujala, IKDC and Lysholm scores after 3, 6 and 12 months, and the results were compared for the different follow-up times and patient’s trochlear dysplasia degree.ConclusionThis prospective observational longitudinal study identified good clinical outcomes in patients who underwent MPFL reconstruction and ATT transposition for patellar instability. Finally, the different risk factors for patellar instability examined, particularly the presence of trochlear dysplasia, did not significantly influence the final functional results, which range from good to excellent without re-dislocation episodes.

Reconstruction of the medial patellofemoral ligament is effective in treating lateral patellofemoral instability, even in the presence of trochlear dysplasia. A review of 18 cases

Reconstruction of the medial patellofemoral ligament is effective in treating lateral patellofemoral instability, even in the presence of trochlear dysplasia. A review of 18 cases

Evaluation of Trochlear Dysplasia in Dogs with Medial Patellar Luxation - Comparative Studies

Background: Medial patellar luxation (MPL) is one of the commonest orthopaedic diseases in small dog breeds. Although the bone deformities associated with canine medial patellar luxation are described in numerous studies, the pathogenesis of the condition is still disputable. What is more, there is no categorical evidence that luxation of the patella is associated to a shallow trochlear groove as no objective method for determination of trochlear depth and shape has been proposed. The aim of the present study was to evaluate the depth and shape of femoral trochlear groove on radiographs obtained from healthy dogs and dogs affected with grade II and grade III MPL.Materials, Methods &amp; Results: A total of 45 dogs (33 with MPL and 12 healthy) from 4 small breeds (Mini-Pinscher, Pomeranian, Chihuahua and Yorkshire terrier) were included in the study. After deep sedation, stifle radiographs were obtained in tangential projection (skyline view). The dogs were positioned in ventral recumbency, the examined stifle bent as much as possible, and the central beam focused on the patella between femoral condyles. Six morphometric parameters associated with the onset of trochlear dysplasia similar to those used in human medicine were measured: trochlear sulcus angle (SA), lateral and medial trochlear inclination angles (LTI; MTI), trochlear groove depth (TD), patellar thickness (PaT) and the ratio between trochlear depth and patellar thickness (PaT/TD). The non-parametric Mann-Whitney test was used for evaluation of differences between healthy joints and those affected with grade II and III MPL. The association between measured variables was evaluated via the Spearman’s rank-order correlation. TD was greater in healthy joints as compared to those affected with MPL grade II and III (P &lt; 0.001). In healthy stifles, PaT value exceeded significantly (P &lt; 0.01) that in joints with grade III MPL. The TD/PaT ratio was significantly greater in healthy joints vs both those with grade II (P &lt; 0.01) and grade III MPL (P &lt; 0.001). In healthy joints, there was a significant negative relationship (rho –0.508; P = 0.0113) between SA and TD: smaller sulcus angles corresponded to deeper trochleas. This correlation was even stronger in joints with patellar luxation (rho –0.723; P &lt; 0.0001). The LTI and MTI showed a very strong positive correlation in healthy joints (rho 0.854; P &lt; 0.0001) and at the same time, lack of significant association in joints affected with MPL (rho 0.163; P = 0.327 for grade II MPL and rho 0.175; P= 0.448 for grade III MPL) was demonstrated. The altered trochlear shape and depth were more pronounced in joints with grade III MPL. As MPL grade increased, the SA became statistically significantly greater. In grade III MPL it was accompanied with considerably reduced trochlear depth, medial trochlear inclination angle and trochlear depth/patellar thickness ratio. Discussion: Five of the measured morphometric parameters for radiographic detection of trochlear dysplasia in dogs were found to be important in the evaluation of trochlear morphology in dogs. The obtained results indicated the presence of trochlear dysplasia in dogs with MPL. A 3-stage classification system for assessment of abnormal trochlear development in small dog breeds: mild; moderate and severe trochlear dysplasia, was proposed. The occurrence of shallow trochlear groove and medial femoral condyle’s hypoplasia could be accepted as signs of mild and moderate trochlear dysplasia. The pre-operative measurements of these parameters could improve surgical planning and decisions-making.Keywords: medial patellar luxation, trochlear dysplasia, trochlear depth, small dog breeds.

Robotic-Assisted Patellofemoral Replacement-Correlation of Preoperative Planning with Intraoperative Implant Position and Early Clinical Experience: A Minimum 2-Year Follow-up.

Patello-femoral arthroplasty (PFA) is successful in a selected group of patients and yields a good functional outcome. Robotic-assisted knee arthroplasty has been shown to provide better implant positioning and alignment. We aim to report our early outcomes and to compare Mako's (Robotic Arm Interactive Orthopaedic System [RIO]) preoperative implant planning position to our intraoperative PFA implant position. Data for this study was prospectively collected for 23 (two bilateral) patients who underwent robotic-assisted PFA between April 2017 and May 2018. All preoperative implant position planning and postoperative actual implant position were recorded. Presence of trochlear dysplasia and functional outcome scores were also collected. There were 17 (two bilateral) female and 6 male patients with a mean age of 66.5 (range: 41-89) years. The mean follow-up period was 30 (range: 24-37) months. Eighteen knees (72%) had evidence of trochlear dysplasia. The anterior trochlear line was on average, 7.71 (range: 3.3-11.3) degrees, internally rotated to the surgical transepicondylar axis and on average 2.9 (range: 0.2-6.5) degrees internally rotated to the posterior condylar line. The preoperative planning range was 4-degree internal to 4-degree external rotation, 4-degree varus to 6-degree valgus, and 7-degree flexion to 3-degree extension. The average difference between preoperative planning and intraoperative implant position was 0.43 degrees for rotation (r = 0.93), 0.99 degrees for varus/valgus (r = 0.29), 1.26 degrees for flexion/extension (r = 0.83), and 0.34 mm for proudness (r = 0.80). Six patients (24%) had a different size component from their preoperative plan (r = 0.98). The mean preoperative Oxford Knee Score (OKS) was 16 and the mean postoperative OKS was 42. No patient had implant-related revision surgery or any radiological evidence of implant loosening at final follow-up. Our early results of robotic PFA are promising. Preoperative Mako planning correlates closely with intraoperative implant positioning. Longer follow-up is needed to assess long-term patient outcomes and implant survivorship.

Prediction of recurrence based on the patellofemoral morphological profile and demographic factors in first-time and recurrent dislocators.

Prediction of recurrence in first-time patellar dislocation is an unsolved mystery. Thepurpose of our study is to compare patellar instability patients and normal control groups with anatomical risk factors and validation of newer parameters patello-trochlear index (PTI) and tibial tuberosity-posterior cruciate ligament (TT-PCL) and also to find the significant risk factors that help to predict the recurrence of dislocation in first-time dislocators. This is a comparison study between 50 normal individuals as a control population (group-1) and 94 patients with patellar instability done between 2013 and 2017. Further, 94 patients (group-2) were divided into first-time dislocators (group-2A) and recurrent dislocators (group-2B) which include 39 and 55 patients, respectively. Demographic factors like age, sex, the age of the first dislocation, mechanism of injury, and laterality and MRI risk factors like trochlear dysplasia, patellar height, patellar malalignment, and lateralization of tibial tuberosity were statistically analyzed. All parameters used to measure each MRI factors showed significant difference with p value < 0.0001 between group 1 and group 2 except PTI (0.035) and TT-PCL (0.036). While comparing demographic factors between first-time dislocators and recurrent dislocator groups, patients with first-time dislocation < 16years of age (OR-3.6) and bilateral involvement are associated with recurrence and among MRI factors, trochlear dysplasia (odds ratio OR-12), patellar tilt (OR-0.2), and patella alta (OR-4.9) were known to be associated with higher chance of recurrence. There is a significant difference in anatomic risk factors between normal and patellar instability knees. PTI and TT-PCL are less significant than the previous parameters. Age < 16years, the presence of trochlear dysplasia, patella alta, and bilateral involvement have a significant role as prediction factors in a recurrent dislocation in both adolescents and adults.

Clinical Outcomes After Isolated Medial Patellofemoral Ligament Reconstruction for Patellar Instability Among Patients With Trochlear Dysplasia

Background: Medial patellofemoral ligament (MPFL) reconstruction has become one of the most common and widely used procedures to regain stability among patients with recurrent lateral patellar dislocation. While recent studies demonstrated low recurrence rates, improved patient-reported outcome measures, and a high rate of return to sports, limited literature explored its effectiveness as an isolated intervention in the context of trochlear dysplasia. Purpose: To determine the efficacy of isolated MPFL reconstruction in treating patellar instability in the setting of trochlear dysplasia. Study Design: Case series; Level of evidence, 4. Methods: This was a retrospective review of consecutive patients who underwent uni- or bilateral medial patellofemoral ligament reconstruction for patellofemoral instability with a minimum 2-year follow-up. No osteotomies were included. Pre- and postoperative assessment included ligamentous laxity, patellar crepitus, tilt, translation, apprehension, and radiographic features, including tibial tubercle-trochlear groove (TT-TG) distance, Dejour classification, and Caton-Deschamps index. Results: A total of 121 MPFL reconstructions were included. Mean age at surgery was 23.8 years, and 4.4 dislocation events occurred before surgery. Mean follow-up was 44 months; 76% of patients were female. Mean preoperative TT-TG ratio was 13.5, and mean Caton-Deschamps ratio was 1.2; 92% of patients had Dejour B, C, or D trochlear dysplasia. Kujala score improved from 55.0 preoperatively to 90.0 (P < .001). Almost all patients (94.5%) were able to return to sports at 1 year, with 74% returning to the same or higher level of play. Only 3 patients reported a postoperative dislocation or subluxation event. Discussion: For patients without significantly elevated TT-TG distances or significant patella alta, isolated MPFL reconstruction provides a safe and effective treatment for patellofemoral instability, despite the presence of trochlear dysplasia. Most patients are able to return to sports by 1 year postoperatively at the same or higher level of play.

Femoro Patella Vialla patellofemoral arthroplasty: An independent assessment of outcomes at minimum 2-year follow-up

To determine outcomes using the Femoro-Patella Vialla (FPV) arthroplasty and if there is an ideal patient for this implant. A total of 41 FPV patellofemoral joint replacements were performed in 31 patients (22 females, 9 males, mean age 65 years). Mean follow-up was 3.2 years (minimum 2 years). Radiographs were reviewed preoperatively and postoperatively. We assessed whether gender, age, previous surgery, patella atla or trochlear dysplasia influenced patient satisfaction or patient functional outcome. The median Oxford Knee Score was 40 and the median Melbourne Patellofemoral Score was 21 postoperatively. Seventy-six percent of patients were satisfied, 10% unsure and 14% dissatisfied postoperatively. There was no radiological progression of tibiofemoral joint arthritis, using the Ahlback grading, in any patient. One patient, who was diagnosed with rheumatoid arthritis postoperatively, underwent revision to total knee replacement. There were no intraoperative lateral releases and no implant failures. Gender, age, the presence of trochlear dysplasia, patella alta or bilateral surgery did not influence patient outcome. Previous surgery did not correlate with outcome. In contrast to the current literature, the FPV shows promising early results. However, we cannot identify a subgroup of patients with superior outcomes.

Patellofemoral arthroplasty: outcomes and factors associated with early progression of tibiofemoral arthritis.

The purpose of this study was to review the results of patellofemoral arthroplasty (PFA) performed by a single surgeon at a single institution in order to determine factors associated with clinical outcomes and progression of tibiofemoral degenerative joint disease. Sixty-one patients with isolated patellofemoral osteoarthritis were treated with a PFA by a single surgeon between 2003 and 2009. Fifty-nine patients were available for analysis with a mean follow-up of 4 years (range 2-6 years). Patients were evaluated by measuring range of motion and with the use of the Knee Society clinical rating system, the Tegner Activity Level Scale, and the UCLA Activity Score. In addition, preoperative radiographs were evaluated for patellofemoral and tibiofemoral compartment osteoarthritis and presence of trochlear dysplasia, and post-operative radiographs were reviewed for progression of tibiofemoral degenerative arthritis. Furthermore, multivariate statistical methods were applied to study factors that had potential to influence the final outcome. There was no statistically significant association between age, gender, history of prior knee surgery, patellar height, patellofemoral osteoarthritis severity, patellar and femoral component size, or performance of lateral release with patient pain and function (as measured by the Knee Society scores) or progression of tibiofemoral joint osteoarthritis at final follow-up. Increased preoperative body mass index (BMI) was associated with lower post-operative Knee Society function scores (p=0.03). Patients with preoperative trochlear dysplasia had significantly less radiographic evidence of tibiofemoral joint osteoarthritis progression compared with patients without trochlear dysplasia at final follow-up (p<0.0001). In this study, patients with preoperative radiographic evidence of trochlear dysplasia experienced less progression of tibiofemoral degenerative joint disease than patients without trochlear dysplasia at a mean follow-up of 4 years. IV.

Magnetic Resonance Imaging Findings After Acute Patellar Dislocation in Children.

Background:Acute patellar dislocation (APD) is a common knee injury in children. The pattern and frequency of injury to the medial patellofemoral ligament (MPFL) is different in pediatric compared with adult populations.Purpose:To report on injury patterns sustained to the MPFL after APD in children and to determine whether predisposing factors for APD cited in adults hold true in the pediatric population.Study Design:Case series; Level of evidence, 4.Methods:Magnetic resonance imaging (MRI) studies were reviewed for 36 children sustaining APD. Evidence of injury to the MPFL was documented, and when the MPFL was torn, the location of tear was determined. Presence of trochlear dysplasia, patella alta, tibial tubercle–trochlear groove (TTTG) distance, and thickness of the lateral patellofemoral retinaculum (LPR) were recorded and correlated with MPFL tear.Results:Of the 36 patients sustaining APD, only 16 tore the MPFL. The location of MPFL tear was equally divided between the origin, the insertion, or both, with no case of midsubstance tear. There was a significant correlation identified between MPFL rupture and both LPR thickness greater than 3 mm and TTTG distance greater than 19 mm.Conclusion:The MPFL does not always tear in children who sustain APD, and the tear location is variable. A thickened LPR and increased TTTG distance predispose to MPFL tear.

Patellofemoral osteoarthritis after Insall’s proximal realignment for recurrent patellar dislocation

The aim of the present study was to retrospectively investigate the development of patellofemoral osteoarthritis after the historical Insall's proximal realignment for patellar stabilisation in patients with recurrent patellar dislocation. Furthermore, risk factors for recurrent patellar dislocation and for patellofemoral osteoarthritis development were evaluated. Forty-two patients underwent patellofemoral stabilising surgery by the historic Insall's proximal realignment; they were evaluated with a mean follow-up period of 52 months. Plain radiography was used to document osteoarthritic changes by using the Iwano classification. MRIs obtained at the latest follow-up were evaluated for patellofemoral cartilage lesions. Univariate and multivariate logistic regression analyses were performed to evaluate the influence of trochlear dysplasia, tibial tubercle-trochlear groove distance and patellar height on redislocation. Pearson's χ (2) and the Spearman's correlation tests were used to assess a possible correlation between trochlear dysplasia and patellar dislocation, as well as between instability and development of patellofemoral osteoarthritis. At the latest follow-up, plain radiographs showed a significant increase in patellofemoral osteoarthritis (grades II-IV according to the Iwano classification) in 18 patients (43%) compared with 4 patients (10%) at the time of surgery (P = 0.001). Patellofemoral cartilage lesions (grades II-IV) were detected in 18 patients (43 %) on MRI. Nine patients (21%) had at least one incidence of redislocation at follow-up. Estimated redislocation-associated risk factors could not be determined. Trochlear dysplasia had a significant impact on patellofemoral osteoarthritis development (P = 0.001), whereas recurrent patellar instability had none (n.s.). Insall's proximal realignment technique leads to a significant progression of patellofemoral osteoarthritis. No risk factors for redislocation could be found; however, the presence of trochlear dysplasia did correlate with patellofemoral osteoarthritis. IV.

Prevalence and patterns of anatomical risk factors in patients after patellar dislocation: a case control study using MRI

To assess anatomical risk factors in patients after lateral patellar dislocation (LPD) and controls using MRI. MR images of 186 knees after LPD and of 186 age- and gender-matched controls were analysed. The presence of trochlear dysplasia was assessed by evaluation of trochlear inclination, facet asymmetry, and trochlear depth; patella alta was evaluated by the Insall-Salvati index and Caton-Deschamps index; the lateralised force vector was measured by the tibial tuberosity-trochlear groove (TT-TG) distance. Compared with controls, dislocators had significantly lower values for all three parameters of trochlear dysplasia (-32 %, -32 %, -44 %) and significantly higher values for patella alta (+14 %,+13 %) and TT-TG (+49 %) (all P < 0.001). Trochlear dysplasia was observed in 112 dislocators (66 %), of whom 61 (36 %) additionally had patella alta and 15 (9 %) an abnormal TT-TG. As isolated risk factors, patella alta (15 %) and abnormal TT-TG (1 %) were rare. Only 25 dislocators (15 %) had no anatomical risk factors. Trochlear dysplasia in conjunction with abnormal TT-TG or patella alta is associated with a 37- and 41-fold higher risk. Most dislocators have anatomical risk factors, varying in severity and constellation.

Tibial tubercle advancement osteotomy with bone allograft for patellofemoral arthritis: a retrospective cohort study of 50 knees

Forty consecutive patients (21 females and 19 males) in a single centre underwent 50 tibial tubercle advancement osteotomy procedures for patellofemoral arthritis between January 1993 and April 2007. Twenty knees with patellar maltracking also underwent medialisation of the tibial tubercle (6-12 mm) in addition to the standard 10-15 mm elevation. Femoral head bone allograft blocks were utilised in all cases, and all patients achieved bony union without further surgery. Forty-five knees had previously undergone arthroscopy, 18 with arthroscopic lateral releases. Ninety-four percentage of knees had sustained improvement in visual analogue pain scores (mean improvement of 37.4, P < 0.05) at a mean follow-up of 81 months (range 26-195 months), with 96% of patients still satisfied; and 92% of knees had sustained improvement in Shelbourne and Trumper anterior knee function scores (mean improvement of 39.8, P < 0.05). Overall clinical outcomes were rated excellent/good in 77%, fair in 35% and poor in 8% of knees. Two knees required arthroplasty surgery over the follow-up period (at 18 months and 8 years), and their anterior knee pain and function scores were not included in the analyses. Six knees (12%) suffered major complications: 1 temporary common peroneal neuropraxia; 2 intraoperative tibial metaphyseal fractures; and 3 tibial tuberosity fractures (at 8 days, 3 weeks and 3 months). Four knees (8%) suffered superficial wound infections, 31 knees had some numbness around the midline scar, 7 knees had scar pain lasting up to 12 months, and 22 knees (44%) experienced some discomfort relating to the metalwork, which was removed in all these cases. Tibial tubercle advancement osteotomy can be an effective treatment for anterior knee pain and for patients with arthroscopic evidence of patellar chondral damage. It can provide excellent/good long-term functional results in the majority of patients, with very high satisfaction levels and sustained improvement in pain symptoms. The use of femoral head bone allograft is both effective in obtaining bony union and by definition avoids the donor-site morbidity. Knees with patellar malalignment may also undergo individualised medialisation of the tibial tubercle such that the patella lies in the centre of the femoral trochlea, and may benefit from lateral trochleaplasty surgery in the presence of trochlear dysplasia. However, the major operative complication rate is high at 12%, and fracture of the tibial tubercle is associated with a poorer outcome. One can expect 10% of operated knees to have had some clinical deterioration in the patellofemoral joint by a mean follow-up of 93 months.

The Role of Trochlear Dysplasia in Patellofemoral Instability

Trochlear dysplasia is characterized by abnormal trochlear morphology and a shallow groove. It is associated with recurrent patellar dislocation, but it is unclear whether the dysplasia is congenital, the result of lateral tracking and chronic instability, or caused by a combination of factors. Lateral radiographs elucidate the crossing sign and characteristic trochlear prominence. Recurrent patellofemoral instability is multifactorial, and each component must be considered in determining treatment. Managing other factors associated with recurrent instability may compensate for a deficient trochlea and provide stability. Medial patellofemoral ligament reconstruction is recommended for patellofemoral instability in the presence of trochlear dysplasia in patients without patella alta or increased tibial tubercle-trochlear groove distance. Trochleoplasty should be reserved for severe dysplasia in which patellofemoral stability cannot otherwise be obtained.

Custom Patellofemoral Replacement in the Presence of Trochlear Dysplasia

Corresponding author: Domenick J. Sisto, MD, Los Angeles Orthopaedic Institute, 4955 Van Nuys Boulevard, Suite 615, Sherman Oaks, CA 91403, e-mail: [email protected]

Custom Patellofemoral Replacement in the Presence of Trochlear Dysplasia

To The Editor: I read with interest the article “Custom Patellofemoral Arthroplasty of the Knee” (2006;88:1475-80), by Sisto and Sarin. It is not uncommon for young patients with isolated patellofemoral arthritis to have a dysplastic trochlea. Instead of being concave, the trochlea is …