The Number of Patellar Dislocation Events Is Associated With Increased Chondral Damage of the Trochlea.

BACKGROUND: Patellofemoral instability is associated with chondral injuries to the patella, trochlea, and lateral femoral condyle. Although studies have demonstrated an association between patellar dislocations and chondral injuries, the influence of the number of dislocations on chondrosis is not established. PURPOSE: To elucidate the precise association between the number of patellar dislocation events and the severity of chondral injuries in a multicenter cohort study at the time of patellar stabilization procedures. STUDY DESIGN: Cross-sectional study; Level of evidence, 2. METHODS: A prospective multicenter cohort study (JUPITER [Justifying Patellar Instability Treatment by Early Results]) database was queried for cases of primary patellofemoral instability procedures from December 2016 to September 2022. Cartilage lesions were classified using the International Cartilage Repair Society (ICRS) classification system during an arthroscopic or open evaluation (direct visualization), with grades 2 to 4 considered abnormal. The number of dislocations was categorized as 1, 2-5, and >5. Categorical variables were compared with the chi-square test, and binary logistic regression was performed to identify predictors of the presence of chondral lesions. RESULTS: A total of 938 knees (mean age, 16.2 ± 3.8 years; 61.4% female) were included, with 580 (61.8%) demonstrating a chondral injury. The most affected region was the patella (n = 498 [53.1%]), followed by the lateral femoral condyle (n = 117 [12.5%]) and trochlea (n = 109 [11.6%]). There were no differences in the presence (P = .17) or grade (P = .63) of patellar lesions by the number of dislocations. Patients with >5 dislocations more frequently had trochlear chondral lesions (19.8%) compared with those with fewer dislocations (1, 7.6%; 2-5, 11.0%; P < .001). More dislocations were also associated with a higher proportion of ICRS grade 2 to 4 trochlear lesions (>5, 15.3%; 2-5, 10.0%; 1, 6.9%; P = .015). Combined patellar and trochlear lesions were also more common in those with >5 dislocations (P = .001). In multivariable regression, >5 dislocations was the only variable predictive of a trochlear lesion (odds ratio, 3.03 [95% CI, 1.65-5.58]; P < .001). CONCLUSION: This large prospective cohort study demonstrated that recurrent patellar dislocations can lead to more severe chondral damage in specific locations in the knee. More than 5 dislocations was associated with a >3-fold increase in the incidence and severity of trochlear chondral injuries. There were no differences in the presence or grade of patellar lesions by the number of dislocations. These findings should caution surgeons regarding prolonged nonoperative treatment.

Isolated Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Instability Regardless of Tibial Tubercle-Trochlear Groove Distance and Patellar Height: Minimum 5-Year Outcomes.

BACKGROUND: It remains unclear which subset of patients with recurrent patellofemoral instability would benefit from a concomitant bony realignment procedure in addition to a medial patellofemoral ligament (MPFL) reconstruction. PURPOSE: To provide midterm results for patients who underwent an isolated MPFL reconstruction as part of an ongoing prospective trial. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Patients with recurrent patellar instability were prospectively enrolled in an institutional registry beginning in March 2014. Exclusion criteria included history of a previous surgery for patellar instability, an off-loadable (inferior/lateral) chondral defect, anterior knee pain ≥50% of their chief complaint, and a "jumping J" sign. All patients underwent primary, unilateral, isolated MPFL reconstruction regardless of their bony anatomic characteristics. Patient-reported outcome measures (PROMs), episodes of recurrent instability, and ability to return to sport were obtained annually. Radiographic measurements of baseline radiographs and MRI were obtained at baseline. RESULTS: A total of 138 patients underwent isolated MPFL reconstruction between March 2014 and December 2019. The mean radiographic measurements were tibial tubercle-trochlear groove, 15.1 ± 4.9 mm; Caton-Deschamps index, 1.14 ± 0.16; patellar trochlear index, 46.9% ± 15.1%; trochlear depth index, 2.5 ± 1.2 mm; tibial tubercle to lateral trochlear ridge, -8.4 ± 5.7 mm; and patellar tendon to lateral trochlear ridge, 5.7 ± 6.2 mm. Trochlear dysplasia, defined as a trochlear depth index <3 mm, was present in 79/125 (63%) patients. A total of 50 patients reached ≥5 years, of whom 40 (80%) completed follow-up PROMs. A total of 119 patients reached ≥2 years, of whom 89 (75%) completed follow-up PROMs. Six patients (5%) reported recurrent instability with a mean time of 2.97 years after surgery. All PROMs improved over time except for the Pediatric Functional Activity Brief Scale (Pedi-FABS), which had no change. At 2 years, the mean changes from baseline for Knee injury and Osteoarthritis Outcome Score (KOOS) Quality of Life subscale (QOL), Pedi-FABS, International Knee Documentation Committee (IKDC) score, KOOS Physical Function Short Form (PS), and Kujala score were 42.1, 0.6, 35.1, -23.5, and 32.3, respectively. All changes had P values <.001 except for Pedi-FABS, which showed no change and had P > .999. At 5 years, the mean changes from baseline for KOOS-QOL, Pedi-FABS, IKDC, KOOS-PS, and Kujala score were 42.6, -2.8, 32.6, -21.5, and 31.6, respectively. All changes had P values <.001 except for Pedi-FABS, which showed no change and had P > .453. In total, 89% of patients returned to sport with a mean of 9.1 months. CONCLUSION: Midterm outcomes for patients who underwent isolated MPFL reconstruction were favorable and were maintained at 5 years. Outcomes for the expanded cohort of patients with a minimum 2-year follow-up support previously published results.

Outcomes of Particulated Juvenile Articular Cartilage and Association With Defect Fill in Patients With Full-Thickness Patellar Chondral Lesions.

Background: Cartilage restoration procedures for patellar cartilage defects have produced inconsistent results, and optimal management remains controversial. Particulated juvenile articular cartilage (PJAC) allograft tissue is an increasingly utilized treatment option for chondral defects, with previous studies demonstrating favorable short-term outcomes for patellar chondral defects. Purpose: To identify whether there is an association between defect fill on magnetic resonance imaging (MRI) with functional outcomes in patients with full-thickness patellar cartilage lesions treated with PJAC. Study Design: Case series; Level of evidence, 4. Methods: A retrospective review of prospectively collected data was conducted on patients treated with PJAC for a full-thickness symptomatic patellar cartilage lesion between March 2014 and August 2019. MRI was performed for all patients at 6, 12, and 24 months postoperatively. Patient-reported outcome measures (PROMs) were obtained preoperatively and at 1, 2, and >2 years postoperatively. Clinical outcome scores-including the International Knee Documentation Committee (IKDC) score, the Kujala, the Knee injury and Osteoarthritis Outcome Score-Physical Function Short Form (KOOS-PS), the Knee Injury and Osteoarthritis Outcome Score-Quality of Life (KOOS-QoL), and the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS)-were analyzed and evaluated for a relationship with tissue fill on MRI. Results: A total of 70 knees in 65 patients (mean age, 26.6 ± 8.1 years) were identified, of which 68 knees (97%) underwent a concomitant patellar stabilization or offloading procedure. Significant improvements were observed on all postoperative PROM scores at the 1-, 2-, and >2-year follow-up except for the Pedi-FABS, which showed no significant difference from baseline. From baseline to the 2-year follow-up, the KOOS-QoL improved from 24.7 to 62.1, the IKDC improved from 41.1 to 73.5, the KOOS-PS improved from 35.6 to 15, and the Kujala improved from 52 to 86.3. Imaging demonstrated no difference in the rate of cartilage defect fill between the 3-month (66%), 6-month (72%), 1-year (74%), and ≥2-year (69%) follow-ups. No association was observed between PROM scores and the percent fill of cartilage defect on MRI at the 1- and 2-year follow-up. Conclusion: PROM scores were significantly improved at the 2-year follow-up in patients who underwent PJAC for full-thickness patellar cartilage defects. On MRI, a cartilage defect fill of >66% was achieved by 3 months in most patients. In our sample, PROM scores were not significantly associated with the defect fill percentage at the short-term follow-up.

Bilateral Flexor Digitorum Accessorius Longus Precipitating Bilateral Tarsal Tunnel Syndrome: A Case Report.

CASE: A 29-year-old woman presented with bilateral tarsal tunnel syndrome caused by bilateral flexor digitorum accessorius longus, experiencing immediate relief of symptoms after surgical intervention through 1 year. CONCLUSION: Accessory muscles can cause compressive neuropathies in multiple areas of the body. In patients who have FDAL as the cause of their tarsal tunnel syndrome, surgeons should have a high index of suspicion of bilateral FDAL if the same patient develops similar contralateral symptoms.

Biomechanical Efficacy of Tape Cerclage as an Augment or Stand-alone for Coracoclavicular Ligament Reconstruction.

BACKGROUND: Loss of initial reduction of the acromioclavicular joint after coracoclavicular (CC) ligament reconstruction remains a challenge for various repair techniques. Previous studies using polydioxanone suture cerclage augments for CC ligament reconstruction demonstrated poor clinical and biomechanical outcomes. Tape-style sutures have recently gained popularity because of their added stiffness and strength relative to traditional sutures. These tape cerclage systems have yet to be biomechanically studied in CC ligament reconstruction. PURPOSE: To determine the efficacy of a tape cerclage system as an augment to CC ligament reconstruction. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 24 human cadaveric shoulders were utilized. These were divided into 4 repair groups: anatomic CC ligament reconstruction (ACCR), ACCR with a tape cerclage augment (ACCR + C), tendon graft sling with a cerclage augment (TGS + C), or tape cerclage sling alone (CS). The repairs underwent superior/inferior cyclic loading to evaluate for displacement. Specimens were visually inspected for cortical erosion by the tape cerclage after cyclic loading. Finally, the constructs underwent superior plane load-to-failure testing. RESULTS: Less displacement after cyclic loading was observed in the ACCR + C (mean ± SD, 0.42 ± 0.32 mm), TGS + C (0.92 ± 0.42 mm), and CS (0.93 ± 0.39 mm) groups as compared with the ACCR group (4.42 ± 3.40 mm; P = .002). ACCR + C (813.3 ± 257.5 N), TGS + C (558.0 ± 120.7 N), and CS (759.5 ± 173.7 N) demonstrated significantly greater load at failure relative to ACCR (329.2 ± 118.2 N) (P < .001). ACCR + C (60.88 ± 17.3 N/mm), TGS + C (44.97 ± 9.15 N/mm), and CS (54.52 ± 14.24 N/mm) conferred greater stiffness than ACCR (27.43 ± 6.94 N/mm) (P = .001). No cortical erosion was demonstrated in any specimen after cyclic loading. CONCLUSION: In a cadaveric model at time zero, repairs utilizing a tape cerclage system confer significantly greater load to failure and stiffness, as well as decreased displacement with cyclic loading, when compared with traditional ACCR repair. CLINICAL RELEVANCE: Tape cerclage augmentation may provide a useful augment for CC ligament reconstruction.

Suture Tape Augmentation for the Repair of Index Finger Radial Collateral Ligament Injury: A Biomechanical Study.

PURPOSE: Despite their clinical importance in maintaining the stability of the pinch mechanism, injuries of the radial collateral ligament (RCL) of the index finger may be underrecognized and underreported. The purpose of this biomechanical study was to compare the repair of index finger RCL tears with either a standard suture anchor or suture tape augmentation. METHODS: The index fingers from 24 fresh-frozen human cadavers underwent repair of torn RCLs using either a standard suture anchor or suture tape augmentation. Following the repairs, the initial displacement of the repair with a 3-N ulnar deviating load was evaluated. Next, the change in displacement (cyclic deformation) of the repair after 1,000 cycles of 3 N of ulnar deviating force was calculated (displacement of the 1000th cycle - displacement of the first cycle). Finally, the amount of force required to cause clinical failure (30° ulnar deviation) of the repair was determined. RESULTS: Suture tape augmentation repairs displayed significantly less cyclic deformation (0.8 ± 0.5 mm) after cyclic loading than suture anchor repairs (1.8 ± 0.7 mm). There was no significant difference in the force required to cause the clinical failure of the repairs between the suture tape (35.1 ± 18.1 N) and suture anchor (24.5 ± 9.2 N) repairs. CONCLUSIONS: Index finger RCL repair with suture tape augmentation results in decreased deformation with repetitive motion compared with RCL repair alone. CLINICAL RELEVANCE: Suture tape augmentation may allow for early mobilization following index finger RCL repair by acting as a brace that protects the repaired ligament from deforming forces.

A New Pedigree-Based SNP Haplotype Method for Genomic Polymorphism and Genetic Studies.

Single nucleotide polymorphisms (SNPs) are usually the most frequent genomic variants. Directly pedigree-phased multi-SNP haplotypes provide a more accurate view of polymorphic population genomic structure than individual SNPs. The former are, therefore, more useful in genetic correlation with subject phenotype. We describe a new pedigree-based methodology for generating non-ambiguous SNP haplotypes for genetic study. SNP data for haplotype analysis were extracted from a larger Type 1 Diabetes Genetics Consortium SNP dataset based on minor allele frequency variation and redundancy, coverage rate (the frequency of phased haplotypes in which each SNP is defined) and genomic location. Redundant SNPs were eliminated, overall haplotype polymorphism was optimized and the number of undefined haplotypes was minimized. These edited SNP haplotypes from a region containing HLA-DRB1 (DR) and HLA-DQB1 (DQ) both correlated well with HLA-typed DR,DQ haplotypes and differentiated HLA-DR,DQ fragments shared by three pairs of previously identified megabase-length conserved extended haplotypes. In a pedigree-based genetic association assay for type 1 diabetes, edited SNP haplotypes and HLA-typed HLA-DR,DQ haplotypes from the same families generated essentially identical qualitative and quantitative results. Therefore, this edited SNP haplotype method is useful for both genomic polymorphic architecture and genetic association evaluation using SNP markers with diverse minor allele frequencies.