Lateral Patellar Compression Syndrome Research Articles

Effect of two quadriceps strengthening protocols on morphological characteristics of knee vastus muscles in patients with lateral patellar compression syndrome

IntroductionThe purpose of this study is to compare the effect of two types of quadriceps strengthening protocols on morphological characteristics of the knee vastus muscles in patients with lateral patellar compression syndrome. Methods48 female patients were randomly divided into 3 groups: selective (16), general (17) and control (15). The selective group participated in an isokinetic knee extension training protocol at the last 30° knee extension arc with maximum leg external rotation at high speed with the aim of selectively strengthening the vastus medialis muscle. The general group participated in an exercise protocol aimed at strengthening the entire quadriceps muscle. Both these protocols lasted 8 weeks. The control group did not receive any intervention. The vastus medialis and lateralis muscles cross-sections and fibers angles were measured using an ultrasound device. The data were analyzed using repeated-measures ANOVA and dependent t tests. ResultsAt pre-intervention, there were no differences between groups in muscles cross-sections and fiber angles (P > 0.05), but after interventions, in selective group, the vastus medialis cross-section and fiber angle, as well as vastus medialis to vastus lateralis cross-section ratio, were significantly higher than other groups (P < 0.01). Also, compared to pre-intervention, the vastus medialis cross-section and fiber angle increased only in selective group (P = 0.001), and the vastus lateralis cross-section increased only in general group (P = 0.001). Discussion and conclusionUse of isokinetic extension exercises targeting selectively strengthening the vastus medialis can improve the activity and involvement of this muscle-which is impaired in chronic patellofemoral joint disorders - by changing its morphology.

Effect of open-wedge high tibial osteotomy and lateral patellofemoral retinacular release on patellar position: an X-ray imaging-based comparative study.

Open-wedge high tibial osteotomy (OWHTO) may cause adverse changes in the mechanical environment of the patellofemoral joint. For patients with lateral patellar compression syndrome or patellofemoral arthritis, intraoperative management is still challenging. The effect of lateral retinacular release (LRR) on patellofemoral joint mechanics after OWHTO remains unclear. Our study aimed to evaluate the effect of OWHTO and LRR on the patellar position based on lateral and axial radiographs of the knee joint. The study comprised 101 knees (OWHTO group) undergoing OWHTO alone and 30 knees (LRR group) undergoing OWHTO and concomitant LRR. The following radiological parameters were statistically analyzed preoperatively and postoperatively: femoral tibial angle (FTA), medial proximal tibial angle (MPTA), weight-bearing line percentage (WBLP), Caton-Deschamps index (CDI), Insall-Salvati index (ISI), lateral patellar tilt angle (LPTA), and lateral patellar shift (LPS). The follow-up duration ranged from 6 to 38 months, with a mean of 13.51±6.84 months in the OWHTO group and 12.47±7.81 months in the LRR group. The Kellgren-Lawrence (KL) grading system was used to evaluate changes in patellofemoral osteoarthritis (OA). Regarding the patellar height, preliminary analysis demonstrated a statistically significant decrease in the CDI and ISI in both groups (P<0.05). However, there was no significant difference in changes in CDI or ISI between the groups (P>0.05). In the OWHTO group, although there was a significant increase in the LPTA (P=0.033), the postoperative decrease in the LPS was not significant (P=0.981). In the LRR group, both the LPTA and LPS significantly decreased postoperatively (P=0.000). The mean changes in LPS were 0.03 mm in the OWHTO group and 1.44 mm in the LRR group, indicating a significant change in LPS (P=0.000). However, there was no significant difference in changes in LPTA between the groups, which was contrary to our expectations. Imaging showed no change in patellofemoral OA in the LRR group and progressive changes (from KL grade I to II) in patellofemoral OA in 2 (1.98%) patients in the OWHTO group. OWHTO can cause a significant decrease in patellar height and an increase in lateral tilt. LRR can significantly improve the lateral tilt and shift of the patella. The concomitant arthroscopic LRR should be considered for the treatment of patients with lateral patellar compression syndrome or patellofemoral arthritis.

Inlay, Onlay, Oval, or Round, Patellar Implant Choice Outcomes Do Not Confound: Commentary on an article by Monther A. Gharaibeh, MBBS, FJMA, et al.: "Does Choice of Patellar Implant in Total Knee Arthroplasty Matter? A Randomized Comparative Trial of 3 Commonly Used Designs".

Commentary Although the prevalence of total knee arthroplasty (TKA) continues to grow, the overall outcomes remain good but still exhibit a subgroup of patients who are not entirely satisfied with their result1. Substantial difficulties in evaluating the differences between satisfied and unsatisfied patients are enhanced by the many choices and alternatives available to knee arthroplasty surgeons. A few notable examples include approach (medial parapatellar compared with other approaches), fixation (cemented, hybrid, or uncemented), posterior cruciate ligament status (cruciate-sacrificing compared with cruciate-sparing), and alignment (kinematic compared with mechanical). Included in the long list of alternatives is the choice of patellar implant type used by the surgeon. Many of us have either attended or participated in professional meetings or symposia in which faculty present their biased rationale for supporting their choice of patellar implant (or not resurfacing). Unfortunately, a paucity of strong evidence usually accompanies these conceivably strongly worded recommendations. Gharaibeh et al. should be congratulated for designing and completing a well-done prospective randomized trial assessing the differences between 3 patellar choices: inlay (IN), onlay round (OR), and onlay oval (OO), or anatomic. Historically, patellar instability and pain were common causes of revision TKA. Although infection has overtaken patellar sources of revision, patellar instability and pain remain among the top reasons for revision2. The percentage of unsatisfied patients who underwent TKA secondary to patellar causes is unknown, but patients who undergo revision TKA secondary to patellar sources of pain and instability are a defined subset of those patients undergoing revision TKA. Evidence-based recommendations with regard to patellar implant choices in TKA have been wanting, and Gharaibeh et al. designed a thoughtful and simple prospective trial to answer the question. Thankfully, the investigators randomized consecutive patients to the trial and measured both clinical and patient-reported outcomes. The Kujala score is likely not recognized by U.S. surgeons, but it is a validated method of assessing patellar pain, including in knee arthroplasty. The authors also included a robust set of radiographic measures, and these would have been strengthened by preoperative measurements as well. Their data would have been bolstered by preoperative alignment indices, as postoperative patellar malalignment and tracking can be attributed to overcorrection or undercorrection of underlying abnormalities. The authors also recorded whether a later facetectomy was performed during the procedure. They reported these findings based on their concern for lateral patellar bone compression syndrome. Not surprisingly, they found that a lateral facetectomy was required less frequently with the OO design patellar implants than the OR design patellar implants. Gharaibeh et al. correlated this finding with improved vascularity of the patella in the single photon emission computed tomography (SPECT) Delayed 4 subset, but differences were not noted otherwise in the vascularity analysis. Although the findings are used to imply that the OO-design patellar implants may improve outcomes, this study was not necessarily powered to assess that over time. With regard to outcomes, the authors showed that, although differences in radiographic indices between implant types did achieve significance for the Caton-Deschamps index, the overall indices for all implants were acceptable. Although the overall radiographic indices skewed slightly in favor of the OO design, these differences did not result in improved patient-reported outcomes. The Kujala scores for all implant types showed improvement and no difference between types, and the Knee injury and Osteoarthritis Outcome Score (KOOS) showed minimal and likely clinically unimportant differences between implant types. In conclusion, this is the type of study that helps to advance the science of knee arthroplasty. Although some will take the minimal radiographic differences as evidence that the OO design is superior, the clinical findings, including a patellar-specific outcome, do not support that observation. As we struggle to identify, predict, and address the factors that contribute to unsatisfactory outcomes in knee arthroplasty, this study helps to eliminate patellar implant design as a factor in those poor outcomes.

Morphological Differences of Knee Extensor Muscles Between Women With and Without Lateral Patellar Compression Syndrome

Background and Aims: The morphology of knee joint extensor muscles including vastus medialis (VM) and vastus lateralis (VL), is one of the important and effective factors in lateral patellar compression syndrome (LPCS). This study aims to examine the morphological differences of these knee extensor muscles between women with and without LPCS. Methods: In this causal-comparative study, 15 women with LPCS aged 18-30 years and 15 women without LPCS as controls participated who were selected by a convenience sampling methhod. For muscle imaging, the anteromedial (VM) and anterolateral (VL) thigh distal ends were scanned by using a two-dimensional digital ultrasound device (SonoSite Co., USA). The muscles’ cross-sectional area at the patellar base was measured in square centimeters and the muscle-fiber pennation angles of these muscles was measured in degree. Independent t-test was used to compare the variables between the two groups. The significance level was set at 0.05. Results: The cross-sectional area of VM in the control group was significantly higher than in the LPCS group (P=0.001), while the cross sectional area of VL was not significantly different between the two groups (P&gt;0.05). The muscle-fiber pennation angle of VM in the LPCS group was significantly lower than in the control group (P=0.016), while the muscle-fiber pennation angles of VL in the LPCS group was significantly higher than in the control group (P=0.021). Conclusion: The morphology of VM and VL in women with LPCS symptoms shows a significant muscle imbalance that can change the patella position from normal to a more lateral position and increase the contact between the lateral facet of the patella and the lateral femoral condyle, resulting in increased pressure on this area and eventually knee pain.Muscle morphology, Cross-sectional area, Muscle-fiber pennation angle, Lateral patellar compression syndrome, Knee extensors

Two kinds of lateral retinacular release for lateral patellar compression syndrome:a retrospective comparative study

Objective: To compare the clinical effects of arthroscopic lateral retinacular proximal release and "L" type release for lateral patellar compression syndrome. Methods: Sixty four lateral patellar compression syndrome (LPCS) patients were recruited who had arthroscopic surgery during September 2004 to January 2019 at Department of Sports Medicine,Peking University Third Hospital by the same group of doctors and a retrospective comparative study was conducted accordingly. Among them,24 cases underwent the traditional proximal release of lateral patellar retinaculum (traditional group),including 7 males and 17 females with an age of (42.9±14.6)years(range:23 to 72 years); 40 cases were treated with novel lateral retinacular release of "L" type release revised based on the previous experiences (novel group), consisting of 12 males and 28 females with an age of (54.9±13.1) years (range:28 to 76 years).All the patients participated surveys for the visual analogue scale (VAS),Lysholm score and International Knee Documentation Committee (IKDC) knee function subjective evaluation before and after the operation. The comparison of scores within groups was performed by Wilcoxon test,and comparison between groups was performed by Mann-Whitney U test and Chi-square test. Multivariate analysis was used to evaluate the related factors affecting each score. Results: The follow-up durations of traditional group and novel group were (12.6±1.0) years (range:11.7 to 15.3 years) and (2.2±1.0)years(range:1.0 to 4.4 years) respectively. At the last follow-up,VAS(0(1.0)to 6.0(2.0),Z=-5.471,P<0.01),Lysholm score(98.0(10.0)to 48.0(40.0),Z=-5.511,P<0.01),and IKDC score(82.8(11.2)to 37.4(18.5),Z=-5.444,P<0.01) in novel group were statistically significantly improved,and the postoperative excellent rate of Lysholm score was 97.5% in general. There was no significant difference in the changes of the three scores (P>0.05) between the traditional group and the novel group. However,20.8% (5/24)patients in the traditional group reported significant weakness of the knee extension after surgery,while no such complain was received in the novel group (P<0.01).The results of univariate analysis showed that surgical method was a related factor affecting the changes of VAS before and after surgery (P<0.05).The results of multivariate analysis showed that whether or not with osteoarthritis and operation type were independent factors affecting the changes of Lysholm and IKDC scores (P<0.05). Conclusions: The long-term effect of arthroscopic lateral retinacular release for the treatment of LPCS is satisfactory. Compared with the traditional proximal release surgery,the "L" type release can effectively avoid the complication of significant weakness of the knee extension significantly.

Clinical Outcome of Arthroscopic Lateral Release for Lateral Patellar Compression Syndrome

Objective: In this study, we have evaluated the effects of isolated arthroscopic lateral retinacular release in lateral patellar compression syndrome according to Lysholm Knee Scoring Scale. Methods: a prospective case series study of 48 patients who suffered Lateral patellar compression syndrome who were diagnosed by clinical examination and confirmed by M.R.I. and failed conservative management and underwent isolated arthroscopic lateral patellar retinaculum. Results: There was significant improvement in Lysholm score, in particular for pain, using stairs and squatting. The procedure had a high mean satisfaction score of 83.15 post operatively which is significant compared to preoperative score which was 51.17 (p&lt;0.001). Conclusion: Isolated patella retinaculum release can be effective for relieving anterior knee pain in isolated lateral patellar compression syndrome without significant instability or mal-alignment.

Open versus arthroscopic release for lateral patellar compression syndrome: a randomized-controlled trial

IntroductionLateral patellar compression syndrome is one of the causes of anterior knee pain in young adults and resulted from tight lateral patellar retinaculum. The aim of our study is to compare between open and arthroscopic release of lateral patellar compression syndrome in relation of functional outcome, time of surgical procedure, length of hospital stays, intraoperative and postoperative complications as bleeding, infection, recurrence, and patellar instability with 2 years of follow-up.Materials and methods80 patients, age (21–49 years), were divided randomly into 2 groups (A and B). Group A (40 patients) were treated with open release. Group B (40 patients) were treated by arthroscopic release. All these patients are diagnosed as lateral patellar compression syndrome depending on clinical features and MRI. All patients were assessed by Lysholm knee scoring scale before surgery and at periods of 2, 6 weeks, 6, 12, and 24 months after surgery.ResultsThere is significant difference in functional outcome, measured by Lysholm knee scoring scale, between preoperative and postoperative assessment periods in both groups (P < 0.001). There is significantly better functional outcome at 2 years of follow-up with arthroscopic release (P = 0.018). There is no recurrence in both groups, but there were 4 patients develop medial patellar instability in the group of open release.ConclusionBoth open and arthroscopic lateral release for patients with isolated lateral patellar compression syndrome can be effective surgical procedures, but arthroscopic release can achieve better functional outcome.Trial registration: NCT, NCT04130412. Retrospectively registered on 3rd of June, 2020 at ClinicalTrials.gov.

Isolated Arthroscopic Lateral Retinacular Release for Lateral Patellar Compression Syndrome.

Introduction: Evidence concerning the role of isolated lateral retinacular release (LRR) for lateral patellar compression syndrome (LPCS) dates back at least three decades. Appropriate indications, execution and outcomes still remain unclear and controversial. The present investigation analyzed the midterm result of isolated and arthroscopic LRR for LPCS in a cohort of patients who underwent such procedure at our institution. Material and methods: Patients undergoing isolated arthroscopic LRR for LPCS were identified retrospectively from our electronic database. All procedures were performed by two experienced surgeons. Patients with bony and/or soft tissues abnormalities, patellofemoral instability, moderate to severe chondral damage were not included. Patients with previous surgeries were not included, as were those who underwent combined interventions. Clinical scores and complications were recorded. Results: 31 patients were recruited in the present investigation. The mean follow-up was 86.0 ± 22.8 months. The mean age of the patients at the index operation was 34.2 ± 13.1 years. A total 55% (17 of 31) were women, and 58% (18 of 31) had involved the right knee. The mean hospitalization length was 3.5 ± 1.4 days. At a mean follow-up of 86.0 ± 22.8 months, the numeric rating scale (NRS) was 1.2 ± 0.8, the Kujala score was 91.3 ± 11.3, the Lysholm score was 93.1 ± 15.0, and the Tegner score was 5.0 ± 1.8. At the latest follow-up, 9 of 31 (29.0%) of patients experienced compilations. One patient (3.2%) had a post-operative hemarthrosis which was managed conservatively. Six patients (19.4%) reported a persistent sensation of instability, without signs of patellar dislocation or subluxation. One patient underwent an arthroscopic meniscectomy, and another patient an anterior cruciate ligament (ACL) reconstruction. Conclusion: isolated arthroscopic lateral retinacular release for lateral patellar compression syndrome is feasible and effective, achieving satisfying results at more than seven years following the procedure.

Novel method for diagnosing lateral patellar compression syndrome using X-ray: a retrospective case-control study.

BackgroundA well-established reference is lacking for diagnosing lateral patellar compression syndrome (LPCS), and this diagnosis currently depends on clinicians’ subjective judgment and several examination results. X-rays are primarily used to diagnose LPCS, but they have low detection rates of patellar tilt using the congruence angle (CA) and patellar tilting angle (PTA).MethodsWe enrolled 87 patients (31 men and 56 women; mean age: 42.11±15.33 years) between 2016 and 2019 and divided them as per diagnosis into three groups of 29 each: LPCS, patellar dislocation (PD, control), and meniscus tear (MT, negative control) groups. A senior radiologist and the chief physician of sports medicine examined their patellar axial radiographs of the knee in 30° flexion using a computer imaging system, measuring LPCA, CA and PTA. Univariate analysis of variance and Kruskal-Wallis H test were used to compare measurement data with normal distribution and non-normal distribution, respectively. Bonferroni correction was used to analyze different indicators for different groups. The area under the curve (AUC) was calculated to verify the value of LPCA in the initial diagnosis of LPCS.ResultsLPCA (19.88±7.49) was significantly higher in LPCS group than in MT (13.68±4.69) and PD groups (10.16±4.43) (P<0.01) and was also significantly higher on affected side than on healthy side (16.44±5.00) (P=0.04). LPCA >13.9° had sensitivity and specificity of 89.66% and 68.97%, respectively, for LPCS diagnosis (AUC: 0.82, 95% confidence interval: 0.719–0.891, P<0.001).ConclusionsWe demonstrated that LPCA measured using an axial patellar radiograph of the knee in 30° flexion is high in patients with LPCS, and it may be used for diagnosing LPCS.

High tibial osteotomy combined with lateral retinacular release for the treatment of knee varus osteoarthritis with lateral patellar compression syndrome

To investigate the clinical effect of high tibial osteotomy combined with arthroscopic lateral retinacular release in the treatment of knee varus osteoarthritis. From October 2017 to April 2019, a retrospective analysis was performed on 43 patients with knee varus osteoarthritis and lateral patellar compression syndrome treated by high tibial osteotomy combined with arthroscopic lateral retinacular release. There were 15 males and 28 females, aged 53 to 72(62.05±5.17) years. The visual analogue scale(VAS), Lysholm, and the knee range of motion were used to evaluate knee pain and functional recovery before operation, 2 weeks, 3 months and 12 months after operation. And the congruence angle (CA), patellar tilt angle (PTA), and femala-tibial angle (FTA) were measured respectively before and 12 months after operation to evaluate the congruence of patellar joint, and the improvement of line of gravity of lower limb. All 43 patients were followed up for more than 12 months, with a follow-up time of 14 to 28 (19.60±4.50) months. The VAS scores decreased from 6.65±0.65 before operation to 2.16±0.95, 0.51±0.77 and 0.33±0.64 at 2 weeks, 3 months and 12 months after operation, and the difference was statistically significant (P<0.001). Lysholm score increased from 43.02±8.54 before operation to 46.84±2.81, 72.42±5.30, and 93.40±5.44 at 2 weeks, 3 months and 12 months after operation, and the difference was statistically significant (P<0.001). The knee range of motion increased from (86.97±5.02)° before operation to (99.38±3.27)°, (110.13±4.13)°, and (113.03±4.85)° at 2 weeks, 3 months and 12 months after operation, the difference was statistically significant (P<0.001). The CA decreased from (7.81±1.21)° before operation to (5.82±4.10)° at 12 months after operation, the PTA decreased from (15.87±2.89)° before operation to (13.79±4.26)° at 12 months after operation, and the FTA decreased from(182.61±2.07)° before operation to(170.89±0.89)° at 12 months after operation, and the differences were statistically significant (P<0.05). One case received proper braking and anticoagulation after operation, and was improved after 1 week. The swelling was observed in 14 patients after operation, and subsided about 2 weeks later. High tibial osteotomy combined with arthroscopic lateral retinacular release can relieve weight-bearing pain in frontal axis and improve the function of knee in sagittal axis.

Use of hyaluronic acid injection after arthroscopic release in lateral patellar compression syndrome with degenerative cartilage changes: randomized control trial

BackgroundDegenerative cartilage changes can be seen, in cases of lateral patellar compression syndrome, involving the patellofemoral joint. Hyaluronic acid is a natural component of the synovial fluid and responsible for its elastic features and function of articular surfaces. The aim of this study is to show the effect of intra-articular injection of Hyaluronic acid, after arthroscopic lateral release in lateral patellar compression syndrome, on the functional outcome and knee pain in those patients with degenerative cartilage changes.MethodNinety patients age (30–50) years with lateral patellar compression syndrome and degenerative cartilage changes were divided randomly into 2 groups. Group A was treated by arthroscopic lateral release and received intraarticular injection of Hyaluronic acid 2 weeks after surgery. Group B was treated by arthroscopic lateral release only. Both groups were assessed by Kujala score and visual analogue scale for knee pain preoperatively and re-assessed postoperatively at 3 months, 6 months, 12 months and 24 months.ResultsThere was significant improvement in Kujala score and Visual analogue scale post-operatively in both groups (P-value< 0.001) with better improvement in Kujala score in group A after intra-articular injection of Hyaluronic acid up to 2 year of follow up (P-value = 0.006) as well as better improvement in visual analogue score at 6 months post-operatively (P-value = 0.035).ConclusionIntra-articular injection of Hyaluronic acid after arthroscopic release, in patients with lateral patellar compression syndrome and degenerative cartilage changes, can result in better improvement of knee pain and functional outcome up to 2 years of follow up.Trial registrationNCT, NCT04134611. Registered 18 October 2019 -Retrospectively registered.

T2 mapping on magnetic resonance imaging to diagnose lateral patellar compression syndrome: a report of two cases

T2 mapping on magnetic resonance imaging to diagnose lateral patellar compression syndrome: a report of two cases

Efficacy and experience of arthroscopic lateral patella retinaculum releasing through/outside synovial membrane for the treatment of lateral patellar compression syndrome

BackgroundArthroscopic closure release includes arthroscopic lateral patella retinaculum releasing (LPRR) either outside synovial membrane (OSM) or through synovial membrane (TSM). At present, there is no research to compare the clinical efficacy of the above two methods for the treatment of lateral patellar compression syndrome (LPCS). So, the goal of this study was to investigate the method and overcome of arthroscopic LPRR either OSM or TSM for the treatment of LPCS.MethodsFrom September 2014 to December 2017, 125 patients of LPCS underwent arthroscopic LPRR either OSM or TSM combined with joint debridement. In the OSM group, knee joint was cleaned first. The surface of lateral patella retinaculum (LPR) was created the chamber for arthroscopic operation to release LPR. Synovial membrane was retained. In the TSM group, knee joint was cleaned first. Then synovial membrane, joint capsule and LPR, and superficial fascia were gradually incised from the joint cavity to subcutaneous tissue. The synovial membrane was cut open. Before and after surgery, Lysholm score, patella medial shift, Kujala score, VAS score and surgical complications were collected for evaluating clinical overcomes.ResultsAll patients were followed up for 1.5–5 years. All patients had significant reduction in knee pain and improved function after 1 month and 1 year. The Lysholm score, the distance of patella medial shift, Kujala score, and VAS score in the OSM group and the TSM group were significantly improved in the final follow-up compared with before surgery (All P < 0.001), but these observed targets before surgery and at the last follow-up were compared between the OSM group and the TSM group with no statistical differences. However, the number of occurrences of joint hematoma and adhesion was significantly higher in the TSM group than the OSM group (P = 0.024).ConclusionsArthroscopic closing LPRR for the treatment of LPCS can effectively improve the function and symptoms of patellofemoral joint with the advantages of small trauma, rapid recovery and less complications. But, the number of occurrences of hemarthrosis and joint adhesion were significantly higher in the TSM group than in the OSM group.Trial registrationThe trial registration number (IRCT): IRCT20200205046378N1 and date of registration: February 10, 2020 (retrospectively registered).

When to Add Lateral Soft Tissue Balancing?

Lateral patellofemoral (PF) soft tissue abnormalities range from excessive lateral PF tightness (lateral patellar compression syndrome, lateral patellar instability and arthritis), to excessive laxity (iatrogenic lateral PF soft tissue insufficiency postlateral release). The lateral soft tissue complex is composed of the iliotibial band extension to the patella, the vastus lateralis tendon, the lateral PF ligament, lateral patellotibial ligament, and lateral patellomeniscal ligament, with intimate connections between those structures. To identify lateral retinaculum tightness or insufficiency the most important tests are the patellar glide test and patellar tilt test. Imaging aids in that evaluation relying mostly on the patella position assessed by radiographs, computed tomography, and magnetic resonance imaging with referencing to the posterior femoral condyles. Lateral retinaculum lengthening (preferred) or release may be added when there is excessive lateral retinaculum tightness. A lengthening may be performed using a minimally invasive approach without compromising the lateral patella restraint. Lateral retinaculum repair or reconstruction is indicated when there is lateral retinaculum insufficiency. Lateral retinaculum surgery to balance the medial/lateral soft tissue restraints, improves patellar positioning and clinical results.

The adaptive change of patellofemoral joint after arthroscopic discoid lateral meniscus plasty: An observational study.

The purpose of this study was to investigate the patellofemoral joint adaptive changes after discoid lateral meniscus (DLM) plasty.Forty-one patients with unilateral complete type DLM tears were included in this study. Demographic variables, including gender, age, body mass index (BMI), injury to operation interval, type of injury, and follow-up time, were recorded. The evolution of physical examination, imaging index, and functional score were analyzed by Chi-squared test, Wilcoxon signed ranks test, and Friedman test. Mann–Whitney test was used to analyze the difference at different time points between group PFI > 1.6 and PFI < 1.6.After the patients received arthroscopic DLM plasty, the positive rate of Patella grinding test increased from 19.5% to 29.3%, and it showed significant increased at last follow-up time point (48.8%) (P = .005). Mechanical axis deviation (MAD) significant decreased from −0.7 ± 2.1 mm to −9.4 ± 3.2 mm (P < .001). Lateral patellofemoral angle (LPFA) and lateral shift distance (LSD), respectively, decreased from 11.9 ± 5.8° and 1.0 ± 4.0 mm to 7.2 ± 4.5° and −0.5 ± 3.3 mm (P < .001). Patellofemoral index (PFI) increased from 1.7 ± 0.3 to 1.9 ± 0.4 (P < .001). Kujala score and Lysholm score, respectively, increased from 65.9 ± 10.0 and 85.2 ± 6.4 mm to 61.8 ± 10.2 and 89.5 ± 5.0 (P < .001). Only LSD in group > 1.6 were significant lower than those in group < 1.6 (>1.6: −1.5 ± 2.8, −1.6 ± 2.7, −1.5 ± 2.6; <1.6: 0.8 ± 3.4, 0.4 ± 3.6, 0.6 ± 2.8. P = .010,.038,.011) at the 3 postoperative follow-up time points.After arthroscopic plasty for complete type DLM which decreased the thickness and width of the residual meniscus, in turn causing the varus deformity significantly decreased or a valgus inclination developed. Moreover, the consequent changes of patellofemoral joint caused a certain amount of patellar tilt and patellar dislocation, might aggravated the symptomatic anterolateral knee pain or the lateral patellar compression syndrome.

The Pie Crust Lateral Release Technique Compared to Traditional Lateral Release Techniques in a Cadaveric Study

Lateral patellar compression syndrome is a known cause of chronic anterior knee pain. For patients who have failed conservative treatment, arthroscopic lateral retinacular release is indicated. This procedure has been found to have potential sequelae on patellar instability with iatrogenic medial patellar instability being the most common problem. Recent studies have shown that the “pie crust” method of incision had positive results on patellar instability when implemented with total knee replacements. This study was designed to see if the pie crust method could be a potential arthroscopic surgical technique used for lateral retinacular releases in order to alleviate lateral compression. Using 15 cadaveric knees, the pie crust method was performed on 7 knees and the traditional releases were performed on 8 knees. The pie crust method was performed by using a horizontal stab 1cm in between stabs. K-wires were drilled into the knees to provide landmarks for measurement with digital calipers. Then lateral translation, medial translation, and patellar tilt laxity measurements of the knee cap were made on each of these knees using 0 Newtons, 22 Newtons, and 50 Newtons of force. This study found that the pie crust method increased lateral tilt and lateral retinacular laxity comparable to traditional lateral release techniques. However the pie crust method had a lower percent change of medial translation at both 22 N and 50 N (p value 0.0125, p value 0.011 respectively) compared to the traditional releases on patellar stability. The pie crust method improved tension and increased the lateral patellar tilt on the lateral patella with less subsequent medial instability compared to traditional releases. These results showed that the pie crust method could be a viable option for relieving the lateral patellar compression syndrome.

Lateral Retinaculum Lengthening or Release

Tightness of the lateral patellofemoral (PF) soft tissues is associated with many PF disorders, including lateral patellar compression syndrome, lateral patellar instability, and PF arthritis. Thus, it is an important component of many PF disorders. Although excessive lateral patellar tilt can be recognized on imaging, the contribution of lateral tightness must be verified by physical examination, that is, restraint to medial patellar displacement and lack of neutral patella tilt on physical examination. The indications for lateral release or lengthening for treating PF conditions begin with PF pain; diagnoses are made by physical examination and imaging. Taping and patellar unloading braces can be useful to simulate lateral patella unloading and thus may be predictive of outcome. Lateral lengthening is a more precise balance of the PF forces, and one can titrate more precisely the exact tissue that is being lengthened or released, reducing complication rates. Complications can include overrelease of the lateral structures leading to medial patella instability. Treatment options are closure of the lateral retinaculum, reconstruction of the lateral PF ligament, or lateral patellotibial ligament reconstruction.

Joint motion quality in vibroacoustic signal analysis for patients with patellofemoral joint disorders.

BackgroundChondromalacia, lateral patellar compression syndrome and osteoarthritis are common patellofemoral joint disorders leading to functional and/or structural disturbances in articular surfaces. The objective of the study was to evaluate their impact on joint motion quality via the vibroacoustic signal generated during joint movement analysis.MethodsSeventy-three patients (30 with chondromalacia, 21 with lateral patellar compression syndrome, and 22 with osteoarthritis) and 32 healthy controls were tested during flexion/extension knee motion for vibroacoustic signals using an acceleration sensor. Estimated parameters: variation of mean square (VMS), difference between mean of four maximum and mean of four minimum values (R4), power spectral density for frequency of 50–250 Hz (P1) and 250–450 Hz (P2) were analyzed.ResultsVibroacoustic signals recorded for particular disorders were characterized by significantly higher values of parameters in comparison to the control group. Moreover, differences were found among the various types of patellofemoral joint disturbances. Chondromalacia and osteoarthritis groups showed differences in all parameters examined. In addition, osteoarthritis patients exhibited differences in VMS, P1 and P2 values in comparison to lateral patellar compression syndrome patients. However, only the value of R4 was found to differ between knees with lateral patellar compression syndrome and those with chondromalacia.ConclusionOur results suggest that particular disorders are characterized by specific vibroacoustic patterns of waveforms as well as values of analyzed parameters.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2474-15-426) contains supplementary material, which is available to authorized users.

Diagnosis and Treatment of Lateral Patellar Compression Syndrome

Chronic anterior knee pain with a stable patella is often associated with overload and increased pressure on the lateral facet due to pathologic lateral soft-tissue restraints. “Lateral pressure in flexion” is a term describing the pathologic process of increasing contact pressure over the lateral patellar facet as knee flexion progresses. This report describes a surgical technique developed in response to lateral pressure in flexion and the shortcomings of traditional arthroscopic lateral release procedures. The technique is performed open with the knee in flexion, and the lateral release is repaired with a rotation flap of iliotibial band to close the defect and prevent patellar subluxation. The technique effectively decreases lateral patellar pressure and centers the patella correctly in the trochlear groove with minimal risk of iatrogenic patellar instability.

Partial Lateral Patellar Facetectomy for Treatment of Arthritis Due to Lateral Patellar Compression Syndrome

The purpose of this study was to investigate the intermediate-term results of a retrospective clinical trial designed to establish the value of lateral retinaculum release of the patella in conjunction with partial lateral patella facetectomy in patients with stage III or stage IV patellofemoral arthritis. Between October 1992 and January 2005, all patients undergoing arthroscopy, lateral patellar retinaculum release, and lateral patella facetectomy were evaluated. In total, 66 knees in 63 patients (89%) were available for evaluation at a mean of 60 months after the index surgery. Evaluations consisted of preoperative and postoperative questionnaires, physical examinations, and radiographs. The main outcome measure was the Kujala patellofemoral score. For those patients not undergoing total knee arthroplasty before evaluation, the mean Kujala score was 45.6 preoperatively and 72.0 postoperatively (P < .001); subjectively, 56% of patients were very satisfied, 32% satisfied and would repeat the procedure, 5% were indifferent, and 7% were dissatisfied and would not repeat the procedure. Including all patients who underwent total knee arthroplasty before evaluation and those who would not repeat the procedure or were indifferent, our accumulative failure rate was 17%. Correlations of several measures with the Kujala score, as well as subgroup comparisons of several measures between patients who were satisfied and those who were not satisfied with their reconstructions, were performed. However, all of these failed to achieve statistical significance after adjustment for multiple comparisons and so are not reported in this report. Lateral patella retinaculum release and partial lateral patella facetectomy for end-stage patellofemoral disease provides up to 5 years of symptomatic relief in over 80% of carefully selected patients who do not have significant arthritis (grade IV) in the medial or lateral knee compartments. Significant lateral facet patellofemoral arthritis (grade IV) even in association with medial facet and femoral sulcus involvement is not a contraindication to this surgical approach. Level IV, therapeutic case series.