Lateral Retinacular Release Research Articles

MPFL Reconstruction in Skeletally Immature Patients: Comparison Between Anatomic and Non-Anatomic Femoral Fixation-Systematic Review.

MPFL reconstruction in children with open physis may be challenging, as a major concern during the surgery is to preserve the distal femoral physis. The purpose of this study was to compare the complication rate and the patient-reported outcomes in skeletally immature patients who underwent MPFL reconstruction using an anatomic (A) or non- anatomic (NA) surgical technique. For this systematic review, the authors adhered to the PRISMA guidelines. The literature search was conducted from inception to 31 May 2024. Three databases were used: Pubmed, Scopus and Cochrane library. We included skeletally immature patients who underwent MPFL reconstruction for chronic or recurrent patellar instability. The included studies should describe the surgical technique, report clinical outcomes and complications. Patients with closed physis, prior ipsilateral knee surgery, concomitant surgical procedures except for lateral retinacular release, multiligament knee injury, congenital or acute patellofemoral instability, hyperlaxity or less than 12 months follow up were excluded. Risk of bias was assessed using ROBINS-I, MINORS and MCMS scores. Data from 304 procedures were collected, of which 208 were performed using an anatomic technique and 96 using a non-anatomic technique. Patient age at the time of surgery ranged from 8 to 17 years. The follow-up time ranged between 12 and 116.4 months. Postoperative Kujala (-0.73, p = 0.55) and Tegner (-0.70, p = 0.80) scores were better in the anatomic group compared to the non-anatomic one. Higher rates of recurrent instability (OR 0.91; 95%CI 0.44-1.86, p = 0.85), redislocation (OR 1.21; 95%CI 0.42-3.51, p = 0.8), subluxation (OR 0.73; 95%CI 0.29-1.83, p = 0.62), a positive apprehension test (OR 0.92; 95%CI 0.27-3.13, p = 0.89), stiffness (decreased ROM) (OR 1.63; 95%CI 0.33-1.72, p = 0.54) and reoperation (OR 1.16; 95%CI 0.35-3.80, p = 0.8) were reported in papers using the anatomic technique. The findings of this systematic review reveal that there is no significant difference between anatomic and non-anatomic MPFL reconstruction techniques in terms of patient-reported outcomes and complications. Thus, the choice of surgical technique might be left up to surgeon's preference. Further high-quality, pediatric-oriented studies with long-term follow-up are needed to better guide clinical decision-making.

Subvastus approach improves intraoperative patellofemoral tracking in total knee arthroplasty for varus deformities – An in vivo study

Objectives: The subvastus approach has the theoretical advantages of protecting the extensor mechanism while securing the patellar blood supply, enhanced patellofemoral tracking, faster recovery, decreased post-operative pain, and shortened length of hospital stay at the expense of longer operative and tourniquet times. This study aimed to evaluate the effect of the subvastus approach on patellofemoral tracking. We hypothesize that being a more anatomical approach, the subvastus approach may improve patellofemoral tracking intraoperatively and decrease the necessity to release the lateral retinaculum during total knee replacement (TKR). Methods: In 54 consecutive cases presented with advanced varus osteoarthritis knee in a high-volume arthroplasty hospital from January 2022 to April 2022 and scheduled for cemented posterior stabilized TKR, patellofemoral tracking and the tightness of lateral retinaculum were evaluated intra-operatively all through the whole range of motion (ROM) of the knee by “No thumb test” and “Vertical patella test” subsequent doing the whole tibial and femoral bony cuts, proper sizing, completing soft-tissue release and gap balancing, and reaching the full ROM. Results: The “No thumb test” and “Vertical patella test” were negative in all the patients, and there was no intra-operative dislocation or subluxation. In addition, there was no need to release the lateral retinaculum in any of them. Conclusion: Implementing the subvastus approach during TKR surgeries, with subsequent preservation of the patellar attachment of the vastus medialis oblique muscle, allows for better tracking of the patella over the femur during surgery, resulting in a reduction in the necessity of performing lateral retinaculum release intraoperatively.

Outcomes of total knee arthroplasty combined with the modified "overlap" technique in the treatment of knee osteoarthritis with permanent patellar dislocation

Objective: To investigate the clinical outcomes of total knee arthroplasty (TKA) combined with the modified "overlap" technique in the treatment of end-stage knee osteoarthritis with fixed patellar dislocation. Methods: This is a retrospective case series study. Clinical data of 19 patients (22 knees) who underwent TKA combined with the modified "overlap" technique for the treatment of end-stage knee osteoarthritis with permanent patellar dislocation from January 2011 to January 2022 in the Department of Orthopaedics, the First Affiliated Hospital of Xinjiang Medical University were retrospectively analyzed. The cohort included 5 males (6 knees) and 14 females (16 knees), with an age of (60.6±12.2) years (range:33 to 77 years) and a body mass index of (25.4±4.1) kg/m² (range:20.0 to 33.0 kg/m²). Among them, 11 cases (12 knee) had valgus deformity, with Keblish classification showing mild in 2 cases (2 knees), moderate in 6 cases (6 knees), and severe in 4 cases (4 knees). All cases were treated using a medial parapatellar approach, with lateral retinaculum release combined with the "overlap" technique to restore the patellar trajectory. Knee function was evaluated using the American Knee Society (KSS) Score. Paired sample t tests were used for intergroup comparisons. Results: All patients successfully completed the surgery. Postoperatively, patellar dislocation, knee valgus deformity, flexion contracture deformity, and extensor lag were all corrected. All patients were followed up, with a follow-up duration of (63.8±35.2) months (range:24 to 136 months). One patient experienced periprosthetic infection 2 weeks postoperatively, 1 patient had recurrent patellar dislocation 2 months postoperatively, 1 patient developed knee stiffness 3 months postoperatively and underwent closed manipulation. No other patients exhibited signs of patellar dislocation or subluxation. At the last follow-up, the KSS clinical score improved from (36.4±12.7) points preoperatively to (83.4±6.3) points postoperatively (t=-15.15, P<0.01), and the KSS functional score improved from (30.7±11.1) points preoperatively to (77.6±8.3) points postoperatively (t=-14.37, P<0.01). The range of motion of the knee increased from 81.7°±19.6° preoperatively to 107.6°±12.5° postoperatively (t=-4.85, P<0.01). Conclusion: TKA combined with the modified "overlap" technique is an effective surgical option for the treatment of end-stage knee osteoarthritis with permanent patellar dislocation, demonstrating satisfactory clinical outcomes.

Internal rotational patellar resection and patella alta induced patellar maltracking in total knee arthroplasty: intraoperative measurement of the patellofemoral pressure

BackgroundAnterior knee pain due to patellar maltracking following total knee arthroplasty (TKA) reduces patients’ satisfaction. This study aimed to determine the patellofemoral pressure (PFP) in patients with favorable patellar tracking (FT) and impaired patellar tracking (IT) following TKA, the factors causing patellar maltracking, and the effect of lateral retinacular release (LRR) on patients with IT.MethodsForty-four patients with varus knee osteoarthritis undergoing cruciate-retaining TKA were enrolled. After component implantation, patients with a separation of ≥ 2 mm of the patellar medial facet from the medial femoral trochlea throughout knee range of motion were classified into the IT group; meanwhile, the others were classified into the FT group. PFP was measured intraoperatively in three phases: (1) with the resurfaced patella (RP); (2) with the resurfaced patella and knee (RPK); and (3) when LRR was performed in IT (post-LRR). The PFPs at 0°, 90°, 120°, and 135° knee flexion were compared between FT and IT using the Mann–Whitney U test. Pairwise comparison of the PFP in IT between RPK and post-LRR was performed using the Wilcoxon signed-rank test. Correlations between PFP and pre- and postoperative radiographic parameters, such as hip–knee–ankle angle, lateral distal femoral angle, medial proximal tibial angle, anterior femoral offset, Insall–Salvati ratio (ISR), patellar tilt, and patellar resection angle (PRA), were evaluated using Spearman’s rank correlation coefficients.ResultsHigh lateral PFP in the knee flexion position led to patellar maltracking. Patients with IT (n = 24) had higher lateral and lower medial PFP than did patients with FT (n = 20) at 90°, 120°, and 135° knee flexion in RP and RPK. LRR in IT reduced the lateral PFP in the knee flexion position. PRA and ISR were correlated with the lateral PFP at no less than 90° in RP and RPK.ConclusionsThis study demonstrated that internal rotational patellar resection, which resulted in a thick medial patellar remnant and a thin lateral counterpart, and patella alta were the causative factors of high lateral PFP, which induced patellar maltracking after TKA. Surgeons should avoid internal rotational patellar resection to achieve FT and perform LRR in patients with patellar maltracking.

Poster 283: Revision Patellofemoral Surgery: A Retrospective Cohort Analysis

Objectives: To report demographic and radiologic data, and clinical outcomes of patients undergoing revision surgery for patellar instability Methods: This is a retrospective cohort study. We included patients undergoing revision surgery for patellar instability between January 2010 and January 2022 in our institution. Exclusion criteria included patients with missing information regarding their primary surgery, patients with congenital disorders and patients with a history of distal femoral or proximal tibial osteotomy. Statistical analysis was performed using SPSS v. 20. Results: Ninety-six patients underwent revision surgery for patellofemoral instability. Eight patients were excluded based on exclusion criteria (Figure 1). Of the 88 patients included in final analysis, 44 (50%) had their primary surgery in our institution and revision rate in our institution was 3.8%. Primary surgeries included lateral retinacular release (LRR):18, medial patellofemoral ligament (MPFL) reefing: 19, MPFL reconstruction (MPFLR): 33, Tibial tubercle osteotomy (TTO): 24 (Table 1). Revision surgeries included: Lateral patellofemoral ligament reconstruction for iatrogenic medial instability: 6, MPFL release for persistent pain: 3, MPFLR: 36, MPFLR with Patellar tendon shortening: 5, MPFLR with Trochleoplasty: 4, Revision of femoral screw: 1, TTO: 19, TTO+MPFLR: 10, TTO+Trochleoplasty: 1, TTO+MPFLR+Trochleoplasty: 3 (Table 2). Patients having LRR as primary surgery had more female patients and higher patellar tilt, MPFLR patients had higher incidence of trochlear dysplasia, MPFL reefing patients were younger (Table 1). In our cohort of patients undergoing revision surgery for patellar instability, the mean tibial tubercle-trochlear groove (TT-TG) distance was 17.2 mm and the mean Caton-Deschamps Index (CDI) was 1.42. The incidences of trochlear dysplasia and skeletally immature patients were 61% and 68.2%, respectively (Table 1). The Median follow up period after revision surgery was 81 months. The overall complication rate after revision surgery was 12.5% (11/88) and occurred at a median of 31.5 months. Ten patients had recurrent patellar instability and one patient had tibial tubercle fracture (Table 3). Conclusions: The overall incidence of revision surgery was 3.8 after a primary surgery for patellar instability at a median of 31.5 months. Complications occur in 12.5% of patients after the revision surgery with the majority (10/11) being recurrent patellar instability. In our cohort, CDI and the incidences of trochlear dysplasia and skeletally immature patients were increased while the mean TT-TG distance was not.

Paper 35: Number of Patellar Dislocation Events are Associated with Increased Chondral Damage of the Trochlea: data from the JUPITER group

Objectives: Patellofemoral instability (PFI) is frequently associated with chondral injuries to the patella and trochlea. Though several radiographic and intra-operative studies have demonstrated a link between patellar dislocation and chondral injury, the influence of the number of patellar dislocation events on the presence of chondral wear and severity is not established. This study aimed to understand the association between the number of patellar instability events and chondral damage observed directly in a large patient population undergoing patellar stabilization procedures. Methods: This was a retrospective review of the prospective multi-center Justifying Patellar Instability Treatment by Results (JUPITER) cohort. All patients undergoing primary surgical procedures to address PFI from 12/2016 to 9/2022 with a recorded number of patellar dislocations and detailed intra-operative assessment of the articular cartilage were included. Cartilage lesions were classified using the International Cartilage Repair Society (ICRS) classification, where ICRS grades 2 to 4 are defined as abnormal or severely abnormal. The number of dislocation events was grouped into 1-2, 3-5, and &gt;5 dislocations. Continuous and categorical variables were compared using independent t-tests and chi-squared tests, respectively with multivariable regressions used to control for demographic characteristics potentially influencing cartilage wear. A significance threshold of p&lt;0.05 was used. Results: A total of 938 patients at mean age 16.2 ± 3.8 years (range 5.1-35.0 years, 61.4% female patients) undergoing PFI procedures were included. Of these, 580 (61.8%) demonstrated a chondral injury. The most commonly affected region was the patella (n = 498, 53.1%) followed by the femoral condyles (n = 148, 15.8%), and trochlea (n = 109, 11.6%), with 83 (8.8%) patients having lesions located on both the patella and trochlea (Table 1). MPFL reconstruction was performed in 861 (91.8%) cases (Table 2), with other commonly performed procedures including patellofemoral chondroplasty (n = 388, 41.4%) and lateral retinacular lengthening or release (n = 255, 27.2%). Patients with fewer dislocations more frequently underwent fixation of an osteochondral fragment (1-2: 19.5%, 3-5: 7.6%, &gt;5: 1.7%, p&lt;0.001). There were no differences in the presence (p=0.209) or grade (p=0.716) of patellar chondral lesions based on dislocation number (Table 3). Patients with &gt;5 patellar dislocations more frequently had a trochlear chondral lesion (19.8%) compared to the groups with fewer dislocations (1-2: 8.4%, 3-5: 13.0%, p&lt;0.001). A greater number of dislocations was also associated with a higher proportion of abnormal (ICRS grades 2-4) trochlear lesions (&gt;5: 15.3%, 3-5: 11.7%, 1-2: 7.6%, p=0.009), and the mean trochlear ICRS grade was significantly greater for the highest dislocator group (&gt;5, mean 0.45 ± 0.99, p=0.023) compared to those with fewer dislocations (1-2: mean 0.24 ± 0.84, 3-5: mean 0.34 ± 0.93). Combined patellar and trochlear lesions were also higher in the most frequent dislocation group (&gt;5 dislocations: 15.8%, 3-5: 9.9%, 1-2: 6.1%, p&lt;0.001). In multivariable regression accounting for age, sex, BMI, and dislocation count, a dislocation count &gt;5 was the only variable significantly predictive of the presence of a trochlear chondral lesion (OR 2.16, 95% CI 1.36-3.43, p=0.001). Both age in years (OR 1.11, 95% CI 1.06-1.16, p&lt;0.001) and BMI (OR 1.05, 95% CI 1.02-1.07, p&lt;0.001) were predictive of a patellar lesion, while both age in years (OR 1.07, 95% CI 1.01-1.13, p=0.017) and dislocation count &gt;5 (OR 2.25, 95% CI 1.35-3.75, p=0.002) were predictive of the presence of both a patellar and trochlear lesion. Conclusions: This study demonstrates that an increased number of patellofemoral dislocation events is associated with more frequent trochlear and combined patellar/trochlear chondral damage with higher injury severity. Specifically, a dislocation count &gt;5 is associated with a greater than 2-fold increase in the number of trochlear chondral injuries, which are of higher severity potentially requiring surgical management. Conversely, patients with fewer dislocation events were more likely to undergo osteochondral fracture fixation, which may have driven earlier operative intervention in this group. This is the first, large prospective study to demonstrate that multiple patellar dislocations can result in increased and more severe chondral damage.

Evaluation of Differences in Patellar Height After Patellar Stabilization Procedures Not Intended to Address Patella Alta: A Multicenter Study.

Recent studies have reported conflicting results as to whether isolated medial patellofemoral ligament reconstruction (MPFLr) leads to decreased patellar height. To investigate if patellar stabilization surgery not intended to address patella alta influences patellar height. Cohort study; Level of evidence, 3. A multicenter retrospective chart review was conducted, and patients who underwent MPFLr, medializing tibial tuberosity osteotomy (TTO), and/or trochleoplasty between 2016 and 2020 were included. The Caton-Deschamps index (CDI) was calculated from radiographs obtained preoperatively, 2 weeks postoperatively, and 3 months postoperatively. The preoperative CDI value was compared with the 2-week postoperative and 3-month postoperative values according to stabilization procedure (isolated MPFLr, isolated TTO, MPFLr + TTO, MPFLr + trochleoplasty, and MPFLr + trochleoplasty + TTO) using the paired t test. Analyses of the 1-bundle versus 2-bundle MPFLr technique and the presence of lateral retinacular release or lateral retinacular lengthening were conducted on the isolated MPFLr and combined MPFLr + TTO cohorts. A total of 356 knees were included. Statistically significant pre- to postoperative decreases in CDI were seen in all stabilization procedures analyzed (P≤ .017 for all). Within the isolated MPFLr cohort, this significant decrease was seen at 2 weeks postoperatively with the 2-bundle technique (ΔCDI = -0.09; P < .001) but not with the 1-bundle technique (ΔCDI = -0.01; P = .621). The different surgical techniques analyzed in the current study affected patellar height, even when a distalizing TTO was not performed. The decrease was dependent on surgical technique, with a 2-bundle MPFLr leading to a statistically significant decrease and a 1-bundle MPFLr effecting no change.

Meta-analysis of factors influencing anterior knee pain after total knee arthroplasty.

Total knee arthroplasty (TKA) is a mature procedure recommended for correcting knee osteoarthritis deformity, relieving pain, and restoring normal biomechanics. Although TKA is a successful and cost-effective procedure, patient dissatisfaction is as high as 50%. Knee pain after TKA is a significant cause of patient dissatisfaction; the most common location for residual pain is the anterior region. Between 4% and 40% of patients have anterior knee pain (AKP). To investigate the effect of various TKA procedures on postoperative AKP. We searched PubMed, EMBASE, and Cochrane from January 2000 to September 2022. Randomized controlled trials with one intervention in the experimental group and no corresponding intervention (or other interventions) in the control group were collected. Two researchers independently read the title and abstract of the studies, preliminarily screened the articles, and read the full text in detail according to the selection criteria. Conflicts were resolved by consultation with a third researcher. And relevant data from the included studies were extracted and analyzed using Review Manager 5.4 software. There were 25 randomized controlled trials; 13 were comparative studies with or without patellar resurfacing. The meta-analysis showed no significant difference between the experimental and control groups (P = 0.61). Six studies were comparative studies of circumpatellar denervation vs non-denervation, divided into three subgroups for meta-analysis. The two-subgroup meta-analysis showed no significant difference between the experimental and the control groups (P = 0.31, P = 0.50). One subgroup meta-analysis showed a significant difference between the experimental and control groups (P = 0.001). Two studies compared fixed-bearing TKA and mobile-bearing TKA; the results meta-analysis showed no significant difference between the experimental and control groups (P = 0.630). Two studies compared lateral retinacular release vs non-release; the meta-analysis showed a significant difference between the experimental and control groups (P = 0.002); two other studies compared other factors. Patellar resurfacing, mobile-bearing TKA, and fixed-bearing TKA do not reduce the incidence of AKP. Lateral retinacular release can reduce AKP; however, whether circumpatellar denervation can reduce AKP is controversial.

Lateral Lengthening and Lateral Release

The lateral retinaculum is a complex, layered structure that is the primary constraint to medial translation of the patella. Patients can develop patellar hypercompression syndrome and arthritis of the lateral patellofemoral joint from an overly tight lateral retinaculum. Conservative treatments include physical therapy and bracing but if relief is not achieved, surgical treatment in the form of lateral retinacular lengthening or release may alleviate symptoms. This chapter provides a thorough background of the risks, indications, outcomes, and techniques regarding treatment of the lateral retinaculum.

Lateral Retinacular Release for Treatment of Excessive Lateral Pressure Syndrome: The Capsule-Uncut Immaculate (CUI) Technique

Lateral retinacular release of the patella is the main surgical treatment for excessive lateral pressure syndrome. It was first described by Merchant and Mercer in 1974. The main complications of arthroscopic lateral retinacular release are hemarthrosis and medial patellar instability. The main causes of these complications are the disturbance of the synovial membrane of the joint capsule and excessive release of the lateral retinaculum. In this article, we introduce a method for arthroscopic lateral retinacular release that maintains the overall structure of the joint capsule: capsule-uncut immaculate (CUI) lateral retinacular release.

Influence of Lateral Retinacular Release in Realigning the Patella Between Varus and Valgus Knees in Primary Total Knee Arthroplasty.

Our study aims to find the role of lateral retinacular release (LRR) on realigning the patella in knees with maltracking during primary total knee arthroplasty. We also compared the patellar morphological factors between the varus and valgus knees on predicting the need for LRR. We have retrospectively analyzed the incidence of LRR in consecutive 152 primary TKA (124 patients) from May 2018 to December 2018. We have evaluated the preoperative radiological parameters like Wiberg's patellar morphological type, patellar angle, sulcus angle, patellar width and thickness, preoperative patellar tilt and patellar shift, lateral patellofemoral angle and congruent angle. Post-operatively, patellar shift and patellar tilt were measured. Multivariate regression analysis was used to find the association of LRR with the individual radiological parameters. There was no statistical difference in the postoperative patellar shift and tilt between lateral released and non-released groups, suggesting realignment of the patella after LRR (p > 0.05). The morphological parameters like patellar shift, lateral patellofemoral angle and congruent angle were significantly increased in valgus knees compared to varus knees (p < 0.05). The preoperative patellar shift of > 3.5mm have a specificity of 93.7% and a negative predictive value (NPV) of 92.7%, congruent angle > 16° have a specificity of 85.3% and NPV of 4.2% in varus knees in predicting LRR. Radiological parameters of patellar maltracking like increased patellar tilt and lateral patellar shift get corrected postoperatively after performing the lateral release. Patella with Wiberg type 3 morphology, patellar shift > 3.5mm and congruent angle > 16° in axial view tend to have an increased chance of lateral retinacular release.

Diagnosis and treatment of patellofemoral joint arthritis

Background: Although patellofemoral arthritis is a common and debilitating orthopedic disorder, its treatment varies and remains controversial. This review aims to provide an overview of the current understanding of the pathophysiology of patellofemoral arthritis, as well as its various diagnostic and treatment options.Current Concepts: The pathophysiology of patellofemoral arthritis includes lower limb malalignment, trochlear and/or patellar dysplasia, patellar instability, trauma, and obesity. The disorder is characterized by chronic anterior knee pain aggravated by flexion of the knee joint. A critical imaging study of the Merchant and lateral knee radiographs may show the progression of patellofemoral arthritis and dysplasia of the patellofemoral joints. Non-pharmacologic treatment options for patellofemoral arthritis include patient education, self-management, exercise, weight loss, taping, bracing, and orthotics. Pharmacologic agents (non-steroidal anti-inflammatory drugs, acetaminophen, oral narcotics, and duloxetine) and intra-articular injection therapies (glucocorticoids, hyaluronic acid, platelet-rich plasma, and other regenerative therapies) can be helpful for symptom relief in patients with patellofemoral arthritis. The surgical treatment can begin with lateral retinacular release to realign and decompress the patellofemoral joint. If failure in the improvement of symptoms is noted, a tibial tubercle osteotomy can be considered in young and active patients. While the early design and technique of patellofemoral arthroplasty were less than encouraging, more recent implant design and surgical techniques have demonstrated robust results.Discussion and Conclusion: Patellofemoral arthritis is a unique entity compared with tibiofemoral arthritis marked by distinct epidemiology, biomechanics, and risk factors and treatment options. It is essential to understand its pathophysiology and ensure proper treatment options.

Poster 266: Outcomes of Surgical Stabilization for Recurrent Patellar Instability in Competitive Wrestlers: Outcomes, Reoperations, and Return to Play at 6 years Mean Follow Up

Objectives: The purpose of this study was to assess return to play (RTP), patient-reported outcomes (PRO), and reoperation rates following patellofemoral stabilization surgeries (PSS) for recurrent patellar instability (RPI) in a cohort of competitive wrestlers. Methods: All competitive wrestlers with a history of an RPI and subsequent PSS at a single institution between 2000 and 2020 were identified. Primary PSS ranged from MPFL reconstruction (n = 31; 50%) or MPFL repair (n = 22; 33.5%), and other PSS (n = 9; 14.5%) in the form of tibial tubercle osteotomy (TTO), lateral retinaculum release (LRR), and medial retinaculum reefing (MRR). Exclusion criteria included revision PSS, or concomitant anterior cruciate ligament reconstruction or multi ligament knee injury. All patients were contacted for determination of reinjury rates, current sport status, and PROs. Surgical failure defined as subsequent patellar dislocation despite operative management or need for secondary PSS. Results: Ultimately, 62 knees in 56 wrestlers were included at a mean follow-up time of 6.6 years (range, 2.0 – 18.8 years). RTP occurred in 55.3% of wrestlers at a mean of 8.8 ± 6.7 months. Among the PSS no differences were observed between rates of RTP (P = .676), postoperative pain (P = .176), Tegner activity level (P = .801), International Knee Documentation Committee (P = .378), Lysholm (P = .402), or Kujala scores (P = .370). Recurrent patellar instability was the most common complication in 21% of knees. Among PSS types, MPFL reconstruction had the lowest rate of RPI (6.5% vs. 27.3% vs. 55.6%; P = .005), and surgical failure (9.7% vs. 31.8% vs. 55.6%; P = .008). Kaplan-Meier survivorship free from surgical failure of the entire cohort was 91.9% at 1 year, 77.7% at 5 years, and 65.7% at 15 years. MPFL reconstruction had the highest survivorship when compared to MPFL repair and other PSS up to 10 years after the index surgery (90.3% vs. 64.1% vs. 27.8%; P = .048). Conclusions: Recurrent patellar instability remains a concern for competitive wrestlers after PSS. MPFL reconstruction may serve as a more durable surgical treatment option with lower rates of RPI and failure when compared to other PSS up to 10 years after surgery. [Table: see text]

Surgical Stabilization for Recurrent Patellar Instability in Competitive Wrestlers: Outcomes, Reoperations, and Return to Play at 6-Year Mean Follow-up

Background: The extent to which recurrent patellar instability (RPI) affects wrestlers has not been thoroughly examined. Purpose: To assess return to wrestling (RTW), patient-reported outcomes, and reoperation rates after patellofemoral stabilization surgery (PFSS) for RPI in a cohort of competitive wrestlers. Study Design: Cohort study; Level of evidence, 3. Methods: All competitive wrestlers with a history of RPI and subsequent PFSS performed at a single institution between 2000 and 2020 were identified. Primary PFSS procedures included medial patellofemoral (MPFL) reconstruction (n = 31; 50%); MPFL repair (n = 22; 35.5%); or other PFSS (n = 9; 14.5%), such as tibial tubercle osteotomy, lateral retinacular release, and/or medial retinacular reefing. Exclusion criteria included revision PFSS or concomitant anterior cruciate ligament reconstruction or multiligament knee injury. Surgical failure was defined as subsequent patellar dislocation despite operative management or need for secondary PFSS. Results: Ultimately, 62 knees in 56 wrestlers with a mean age of 17.0 years (range, 14.0-22.8 years) were included at a mean follow-up of 6.6 years (range, 2.0-18.8 years). RTW occurred in 55.3% of wrestlers at a mean ± SD 8.8 ± 6.7 months. Among PFSS types, no differences were observed in rates of RTW (P = .676), postoperative pain (P = .176), Tegner activity level (P = .801), International Knee Documentation Committee (P = .378), Lysholm (P = .402), or Kujala scores (P = .370). RPI was the most common postoperative complication (n = 13; 21.0%). MPFL reconstruction had the lowest rate of RPI (6.5% vs 27.3% [repair] vs 55.6% [other]; P = .005) and surgical failure (9.7% vs 31.8% [repair] vs 55.6% [other]; P = .008). Kaplan-Meier survivorship free from surgical failure of the entire cohort was 91.9% at 1 year, 77.7% at 5 years, and 65.7% at 15 years. MPFL reconstruction had the highest survivorship when compared with MPFL repair and other PFSS up to 10 years after the index surgery (90.3% vs 64.1% vs 27.8%; P = .048). Conclusion: RPI remains a concern for competitive wrestlers after PFSS. MPFL reconstruction may serve as a more durable surgical treatment option with lower rates of RPI and failure when compared with other PFSS procedures at up to 10 years after surgery.

Midvastus Versus Medial Parapatellar Approach in Simultaneous Bilateral Total Knee Arthroplasty

BackgroundThe purpose of this study was to compare the postoperative outcomes over a period of 3 years in patients who underwent bilateral total knee arthroplasty (TKA) using midvastus (MV) versus medial parapatellar (MPP) approaches. MethodsIn this retrospective study, 2 propensity-matched cohorts of patients who underwent simultaneous bilateral TKA via MV (n = 100) and MPP (n = 100) approaches from January 2017 to December 2018 were compared. Surgical parameters compared were surgery time and the incidence of lateral retinacular release (LRR). Clinical parameters including the visual analog score for pain, time for straight leg raise (SLR), range of motion, the Knee Society Score, and the Feller patellar score were assessed in the early postoperative and follow-up periods up to 3 years. Radiographs were evaluated for alignment, patellar tilt, and displacement. ResultsLRR was performed on 17 knees (8.5%) in the MPP group and 4 knees (2%) in the MV group which was significant (P = .03). The time to SLR was significantly lower in the MV group. There was no statistically significant difference in the length of hospital stay between the groups. The visual analog score, range of motion, and Knee Society Score were better in the MV group within 1 month (P < .05), but no statistically significant differences were found later. Patellar scores, radiographic patellar tilt, and displacements were similar at all follow-up periods. ConclusionIn our study, the MV approach had faster SLR, less LRR, and better pain and function scores in the first few weeks after TKA. However, its effect on different patient outcomes has not been sustained at 1 month and further follow-up points. We recommend that surgeons use the surgical approach with which they are most familiar.

Lateral Retinacular Release During Medial Unicompartmental Knee Arthroplasty in the Presence of Patello-Femoral Joint Arthritis Relieves Patello-Femoral Joint Pressure and Improves Associated Symptoms

BackgroundThis study evaluated the effects of concomitant lateral patellar retinacular release (LPRR) during medial unicompartmental knee arthroplasty (UKA). MethodsWe retrospectively analyzed 100 patients who had patello-femoral joint (PFJ) arthritis who underwent medial UKA with (n = 50) and without (n = 50) LPRR who had ≥2 years follow-up. Radiological parameters associated with lateral retinacular tightness, including patellar tilt angle (PTA), lateral patello-femoral angle (LPFA), and congruence angle, were measured. Functional evaluation was performed using the Knee Society Pain Score, Knee Society Function Score (KSFS), Kujala Score, and the Western Ontario McMaster Universities Osteoarthritis Index score. Intraoperative patello-femoral pressure evaluation was performed on 10 knees to evaluate the pressure changes before and after LPRR. Mann–Whitney U-tests were used for statistical analyses. ResultsDemographic data did not differ between the LPRR(+) and LPRR(−) groups. A decrease in PTA and an increase in LPFA were observed in the LPRR(+) group compared to those in the LPRR(−) group (PTA; −0.54 versus −1.74, P = .002, LPFA; 0.51 versus 2.01, P = .010). The LPRR(+) group showed significantly better KSFS and Kujala scores than the LPRR(−) group (KSFS: 90 versus 80, P = .017; Kujala score: 86 versus 79, P = .009). Intraoperative patello-femoral pressure analysis showed a 22.6% reduction in the PFJ contact pressure and an 18.7% reduction in PFJ peak pressure after LPRR. (P = .0015, P < .0001, respectively) ConclusionA LPRR during UKA may be a simple and useful adjunct procedure to relieve PFJ symptoms with concomitant PFJOA.

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.

Lateral Patellar Instability.

Patellar instability represents a common problem with an evolving understanding and multifactorial pathoetiology. Treatment plans should be based on the identification of contributing anatomical factors and tailored to each individual patient. Risks for recurrent instability are dependent on several patient-specific factors including patella alta, increased tibial tubercle-to-trochlear groove (TT-TG) distance, trochlear dysplasia, younger skeletal age, and ligamentous laxity. Cartilage or osteochondral lesions and/or fractures are commonly observed in first-time patellar dislocation, and magnetic resonance imaging (MRI) should be strongly considered. Advanced imaging modalities, such as computed tomography (CT) or MRI, should also be obtained preoperatively to identify predisposing factors and guide surgical treatment. Medial patellofemoral ligament (MPFL) reconstruction with anatomical femoral tunnel positioning is associated with lower recurrence rates compared with MPFL repair and has become a common and successful reconstructive surgical option in cases of instability. Lateral retinacular tightness can be addressed with lateral retinacular release or lengthening, but these procedures should not be performed in isolation. Tibial tubercle osteotomy is a powerful reconstructive tool in the setting of underlying skeletal risk factors for instability and can be of particular benefit in the presence of increased TT-TG distance (>20 mm), and/or in the setting of patella alta. The indications for trochleoplasty are still developing along with the clinical evidence, but trochleoplasty may be indicated in some cases of severe trochlear dysplasia. Several surgical techniques have indications in specific clinical scenarios and populations, and indications, risks, and benefits to each are progressing with our understanding. Combined femoral derotational osteotomy and MPFL reconstruction can be considered for patients with a femoral anteversion angle of >30° to improve patient outcomes and reduce recurrence rates.

Lateral Patellofemoral Ligament Reconstruction: A Biomechanical Comparison of 2 Techniques

Background: The importance of maintaining lateral patellar stabilizing structures has been demonstrated by the presence of iatrogenic medial patellar instability after lateral retinacular release (LRR) procedures. In patients with medial patellar instability, lateral patellofemoral ligament (LPFL) reconstruction has been clinically shown to restore patellar stability while improving patient-reported outcomes. However, the biomechanics associated with different LPFL reconstruction techniques remain largely unknown. Purpose: To (1) investigate whether LPFL reconstruction restores medial patellar translation compared with the intact state after LRR and (2) evaluate for any biomechanical differences between soft tissue and osseous LPFL reconstruction techniques. Study Design: Controlled laboratory study. Methods: A total of 7 knees were included in the final analysis. The knees were dissected, and the tibia and femur were potted. An eye screw was then placed at the midpoint of the patella perpendicular to the medial surface. A custom jig was constructed to allow for a 1-kg load to be applied to the quadriceps muscle. Medial patellar displacement was investigated at 0°, 10°, 20°, 30°, 45°, 60°, and 90° of knee flexion using a tensile testing machine with a 20-N medial force applied to the patella. Medial patellar displacement was assessed in 4 states: intact, LRR, soft tissue LPFL reconstruction (inserted through incisions in the iliotibial band, quadriceps tendon, and patellar tendon), and osseous LPFL reconstruction. Results: The LRR group had significantly greater medial patellar translation compared with the intact group throughout flexion (P < .01 to P = .029). The soft tissue LPFL reconstruction group demonstrated significantly greater medial patellar translation at 30° (P = .020) and 45° (P = .025) compared with the intact group, with less translation compared with the LRR group at all degrees of knee flexion except for 45° (P = .065). The osseous LPFL reconstruction group demonstrated significantly greater medial patellar translation compared with the intact group at 30° of flexion (P = .036), with significantly less translation compared with the LRR group from 0° to 30° (P < .01 to P = .013). The soft tissue LPFL reconstruction group (15.94 ± 2.55 mm) demonstrated significantly greater medial patellar translation at 10° of flexion compared with the osseous LPFL reconstruction group (14.16 ± 2.34 mm) (P = .033). Conclusion: Soft tissue LPFL reconstruction led to significantly greater medial patellar translation at 30° and 45° compared with the intact state, while osseous LPFL reconstruction produced significantly greater translation only at 30°. Both the soft tissue and the osseous reconstruction techniques resulted in comparable medial patellar translation at all degrees of knee flexion except for 10°, in which osseous reconstruction was more similar to the intact state. Clinical Relevance: Compared with LRR, soft tissue LPFL reconstruction was able to restore stability against medial patellar translation at most degrees of knee flexion, while osseous LPFL reconstruction did not provide adequate stabilization beyond 30° of flexion. While the LPFL does appear to have osseous insertions, soft tissue reconstruction functioned more similarly to the intact state after LRR.

Abnormal patellar loading may lead to femoral trochlear dysplasia: an experimental study of patellar hypermobility and patellar dislocation in growing rats

BackgroundThis animal study aimed to explore the effects of patellar hypermobility and patellar dislocation on the developing femoral trochlea.MethodsSeventy-two 3-week-old Wistar rats were randomly divided into three groups. The sham group (SG) underwent simple incision and suture of the skin and subcutaneous tissue; the patellar hypermobility group (PHG) underwent medial and lateral retinacular release and pie-crusting technique for the patellar ligament; the patellar dislocation group (PDG) underwent plication of the medial patellofemoral retinaculum. Twelve rats in each group were euthanized at 3 and 6 weeks postoperatively, respectively, and specimens were collected. The bony sulcus angle (BSA), cartilaginous sulcus angle (CSA), trochlear sulcus depth (TSD), and thickness of the cartilage on the lateral facet (CTL), medial facet (CTM), and center (CTC) of the trochlea were measured on hematoxylin and eosin-stained sections.ResultsIn the PHG and PDG, the femoral condyles became blunt, the trochlear groove became shallower, and cartilage became thicker compared with the SG. Compared with the SG, the PHG and PDG had significantly larger BSA and CSA values at 3 (p < 0.05) and 6 weeks (p < 0.005), and a significantly shallower TSD (p < 0.05). At 3 weeks, all cartilage thicknesses in the PHG and the CTC and CTM in the PDG were significantly thinner than in the SG (PHG vs. SG: p = 0.009 for CTL, p < 0.001 for CTM, p = 0.003 for CTC; PDG vs. SG: p = 0.028 for CTC, p = 0.048 for CTM). At 6 weeks, the CTC was thicker in the PHG and PDG than the SG (PHG vs. SG: p = 0.044; PDG vs. SG: p = 0.027), and the CTL was thinner in the PDG than the SG (p = 0.044).ConclusionPatellar hypermobility and patellar dislocation may result in trochlear dysplasia that worsens with age. Excessive or insufficient loading leads to trochlear dysplasia.