Elias, Tristan J.

Background: Distal femoral osteotomy (DFO) may be performed via either a lateral opening-wedge (LOW) or medial closing-wedge (MCW) osteotomy with meaningful clinical improvements; however, the effects of each DFO technique on leg length have not been well characterized. Purpose: To (1) validate a radiographic measurement technique to predict leg length changes after DFO and (2) compare the change in leg length after DFO for the LOW and MCW techniques. Study Design: Cohort study; Level of evidence, 3. Methods: Preoperative and postoperative full-length standing radiographs obtained from patients who underwent DFO at 1 of 2 academic medical centers were evaluated. The region on the medial (for LOW) or lateral (for MCW) distal femur cortex that would be the “hinge point” during DFO was identified on the radiographs. The distance from the center of the femoral head to the hinge point ( A ), the distance from the hinge point to the center of the talus ( B ), and the resultant angle (α) were measured. The equation presented within the text was used to plot the predicted leg length changes corresponding to the change in alpha angle produced by DFO. Comparisons were made between (1) the predicted and measured leg length changes after DFO and (2) the measured leg length change after LOW versus MCW osteotomies. Results: For both LOW (n = 10) and MCW (n = 10) osteotomies, the predicted leg length change was equivalent to the true change measured on postoperative radiographs (LOW: P = .16; MCW: P = .85). There was a mean lengthening of 0.85 mm (range, 0.5-1.3 mm) for every 1° of mechanical axis correction with LOW DFO, compared to a mean shortening of 0.45 mm (range, 0.1-1.4 mm) per 1° of MCW correction. Conclusion: Preoperative radiographic imaging can be used to predict leg length change after DFO with high reliability. Surgeons can expect approximately 0.85 mm of lengthening per 1° of DFO correction when performing LOW osteotomies, compared to 0.45 mm of shortening per 1° of correction for MCW osteotomies. However, the most accurate prediction results from patient-specific calculations.

Purpose To perform a prospective, double‐blind, randomized controlled trial to assess differences in integration and patient‐reported outcomes metrics (PROMs) of osteochondral allograft transplantation with and without bone marrow aspirate concentrate (BMAC) augmentation. Methods Patients (n = 36) undergoing osteochondral allograft transplantation of the knee were consented and enrolled in this prospective study. They were randomized to either iliac crest BMAC or sham incision groups and blinded to their allocation. Computerized tomography (CT) scans of the knee were obtained at 6 months postoperatively after the index transplantation and graded by the semiquantitative assessment CT osteochondral allograft system. PROMs, including the International Knee Documentation Committee and Knee injury and Osteoarthritis Outcome Score–Joint Replacement, were obtained at 6 months, 1 year, and 2 years postoperatively. Results On 6‐month postoperative CT scans, patients receiving BMAC‐treated grafts were more likely to have small cystic changes ( P = .01), with an associated trend toward reduction in large cyst formation ( P = .06), but equal osseous integration, graft signal density, and presence of discernible clefts and intra‐articular fragments. The BMAC group was less likely to undergo subsequent surgery for graft debridement or revision (5.3% vs 35.3%; P = .02). There were no significant differences in PROMs between the 2 groups preoperatively or postoperatively at 6 months, 1 year, or 2 years. Patients receiving BMAC trended toward a higher rate of achievement of Knee Documentation Committee and Knee injury and Osteoarthritis Outcome Score–Joint Replacement minimal clinically important difference (88% vs 55%; P = .076). Conclusions Patients receiving BMAC‐treated grafts were more likely to have small cystic changes and were less likely to undergo subsequent surgery for persistent or new symptoms after the index procedure. No difference in postoperative PROMs was shown at the 6‐month, 1‐year, and 2‐year follow‐ups between the 2 groups. Level of Evidence Level I, prospective, randomized controlled trial.

Background: Various medial patellofemoral ligament (MPFL) reconstruction techniques have been developed to minimize risks to the physis in skeletally immature patients. Purpose: To examine outcomes of MPFL reconstruction (MPFLR) based on fixation technique in skeletally immature patients. Study Design: Systematic review; Level of evidence, 4. Methods: PubMed, Scopus, Ovid, Cochrane Library, and CINAHL databases were searched for the literature on outcomes of MPFLR in the pediatric population, utilizing various anatomic and nonanatomic techniques. Primary outcomes were postoperative redislocation rates, return-to-sports (RTS) rates, and patient-reported outcomes (PROs). Moreover, outcomes involving sequela of growth plate disturbance were collected. Results: The final analysis included 17 studies—2 using sling-based techniques, 3 using surface-based techniques, 5 using soft tissue realignments, and 7 utilizing transosseous femoral fixations. Higher rates of postoperative redislocation were found in the sling-based (14.8%) and distal soft tissue realignment using semitendinosus tenodesis (38%) techniques, while lower rates were noted with surface-based (1.3%) and transosseous (3.4%) techniques. For PROs, there were large amounts of heterogeneity among studies, but all reported postoperative improvements, with more positive PROs generally seen in anatomic reconstructions. The RTS rate was 100% for surface-based techniques, 79.4% for distal soft tissue realignments, 79.5% for soft tissue realignment techniques, and 83.2% for transosseous techniques. No negative outcomes as a sequela of growth plate disturbance were reported. Conclusion: Nonanatomic techniques—such as sling-based and distal soft tissue realignment techniques—have higher rates of redislocation and lower RTS rates in skeletally immature patients undergoing MPFLR. Surface-based and transosseous tunnel-based techniques were shown to have lower redislocation and higher RTS rates. Clinical Relevance: This review provides insight into the most appropriate surgical management of patellar instability in patients with open growth plates.

Background: Medial patellofemoral ligament reconstruction is frequently indicated for recurrent lateral patellar instability. The preoperative presence and severity of a J-sign have been associated with poorer postoperative outcomes. Purpose: To determine the underlying anatomic factors that contribute to the presence, severity, and jumping quality of the J-sign. Study Design: Cross-sectional study; Level of evidence, 3. Methods: All patients undergoing evaluation for patellar instability at a single institution between 2013 and 2023 and healthy controls without patellar instability were included. Patients with a history of knee osteotomies were excluded. The presence of a jumping J-sign and its relationship to patellofemoral measures including the Caton-Deschamps Index (CDI), trochlear dysplasia (Dejour grade), tibial tubercle–trochlear groove (TT-TG) distance, tibial tubercle lateralization, trochlear bump height, mechanical alignment, femoral anteversion, tibial torsion, trochlear medialization, patellar width, axial patellar/trochlear overlap, patellar height, trochlear height, and knee rotation angle (KRA) were measured using standardized 1.5-T magnetic resonance imaging (MRI). Univariate pairwise and multivariable analyses were performed to determine the factors associated with J-sign presence, severity, and quality. Results: Of the 130 knees with patellar instability, 89 (68.5%) demonstrated a J-sign on physical examination. In total, 44 (33.8%) patients demonstrated a 1-quadrant J-sign, 32 (24.6%) demonstrated a 2-quadrant smooth J-sign, and 13 (10.0%) demonstrated a jumping J-sign. A total of 22 control, noninstability cases were included. On multivariable analysis, increasing TT-TG distance (OR, 1.1 increase per millimeter; P = .04), external KRA (OR, 1.1 increase per degree; P = .02), and increasing CDI (OR, 1.3 increase per 0.1 increase in CDI; P = .02) were associated with J-sign presence. Increasing bump height (OR, 1.72 increase per millimeter; P = .007) and decreasing patellar width (OR, 0.89 decrease per millimeter; P = .076) were associated with a larger J-sign, when present. Increasing bump height (OR, 1.80 increase per millimeter; P = .018), increasing patellar width (OR, 1.33 increase per millimeter; P = .047), and decreasing CDI (OR, 0.009 decrease per 0.01 increase in ratio; P = .008) were associated with a jumping J-sign in comparison with a smooth 2-quadrant J-sign. A KRA of 10° (AUC, 0.70) and a cartilaginous bump height of 6.6 mm (AUC, 0.73) were thresholds associated with jumping J-sign presence. Conclusion: The presence of a J-sign is associated with MRI findings of relatively greater external tibiofemoral rotation, increased TT-TG distance, and increased patellar height, while J-sign severity and jumping quality are associated with the presence of additional underlying trochlear factors such as increased bump height. The anatomic drivers identified in this study should be further evaluated as possible factors associated with suboptimal outcomes after surgical management.

Background: Medial patellofemoral ligament reconstruction (MPFLR) is an excellent surgical option for patients with recurrent patellar instability. This technique has demonstrated significant improvements in patient-reported outcomes, high rates of return to sport, and low rates of failure. However, there is debate regarding the use of isolated MPFLR in the setting of concomitant pathoanatomic features such as patella alta, trochlear dysplasia, or a lateralized tibial tubercle. Purpose: To estimate the overall relative effect sizes as well as strength of evidence supporting described risk factors for recurrent instability after isolated MPFLR. Study Design: Systematic review and meta-analysis. Methods: A systematic review was performed in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed, Embase, Cochrane, and Ovid/MEDLINE databases were queried. Clinical studies for outcomes of isolated MPFLR reporting recurrent instability and associated risk factors were included. Data for each risk factor analyzed by at least 2 studies were extracted, and the heterogeneity of studies was determined by I 2 value. For variables evaluated in studies determined to have fair homogeneity, defined as I 2 <25%, DerSimonian-Laird random-effects models were generated and effect sizes were represented as mean differences or odds ratios. Results: Nine studies examining risk for recurrent instability after isolated MPFLR were identified, with 5 overlapping risk factors with low heterogeneity between studies: age, sex, tibial tubercle to trochlear groove (TT-TG) distance, Caton-Deschamps Index (CDI), and trochlear dysplasia. There was strong evidence to support the risk of recurrent instability associated with CDI >1.3 (OR, 2.72; P = .02) and dysplasia with a trochlear bump (DeJour type B or D; OR, 3.28; P <.001). Age, sex, and TT-TG distance did not cause an increased risk of recurrent instability with currently available aggregate data. Conclusion: There are signs of increased risk of failure of isolated MPFLR in the setting of DeJour type B and D trochlear dysplasia and patella alta (CDI, >1.3). Currently available data suggest that age, sex, and TT-TG distance do not cause a higher risk of recurrence for patients undergoing isolated MPFLR.

Objectives: A DFO can be performed via two techniques: a lateral opening wedge (LOW) osteotomy and a medial closing wedge (MCW) osteotomy. Small case series have looked at how leg length is affected by a lateral opening wedge DFO, however, there is a lack of research comparing these leg length changes to medial closing DFO. Additionally, no studies have presented a model for predicting the leg length changes that will occur following DFO of either technique. Given that limb length differences can lead to accelerated osteoarthritis, back pain, hip pain, and other issues, being able to predict which technique can help prevent this pathology without a secondary procedure would be an important finding. Finally, the medial closing wedge osteotomy can allow for immediate weight-bearing while the lateral opening wedge does not and typically has associated cost with bone grafting. Therefore, we designed this study to validate a tool designed to predict leg length changes after distal femoral osteotomy (DFO) and compare changes following medial closing wedge (MCW) and lateral opening wedge (LOW) techniques. Methods: A collaborative retrospective review was performed of patients from Rush and Mayo Clinic databases who received a DFO and had full-length standing radiographs both pre-and postoperatively. For each preoperative radiograph, the region on the medial (for LOW) or lateral (for MCW) distal femur cortex that would be the “hinge point” during DFO was identified. The distances from the center of the femoral head to the hinge point (“A”), from the hinge point to the center of the tibial plafond (“B”), and the resultant angle at the hinge point (“α”) were measured (Figure 1). Figure 2 demonstrates the equation used to plot a graph of the predicted leg length changes corresponding to the change in α angle produced by DFO. Final leg length was calculated on postoperative radiographs, and the difference between predicted and true leg length changes was compared using paired Wilcoxon signed rank exact tests. Results: 10 MCW and 10 LOW patients were included. For both LOW (n=10) and MCW (n=10) osteotomies, the predicted leg length change was equivalent to the true change measured on postoperative radiographs (LOW P=0.16; MCW P=0.85). LOW DFO’s had 5.10 ± 2.77 mm (range: 1.45-10.87 mm) of leg lengthening, compared to 2.61 ± 1.25 mm (range: 0.50-4.56 mm) of leg shortening (p<0.001) for MCW (Figure 3). On average, there was 0.85 mm of lengthening (range 0.5-1.3 mm) for every 1° of mechanical axis correction with LOW DFO, compared to 0.45 mm of shortening (range: 0.1-1.4 mm) per 1° of MCW correction. Conclusions: This study presents a tool to accurately and reliably predict the leg length changes seen after both medial closing and lateral opening wedge DFO’s. Knowing what leg length changes to expect with each DFO technique is a useful tool that surgeons can utilize during surgical planning. Preoperative radiographic imaging can be used to predict leg length change following DFO with high reliability and accuracy. Surgeons can expect approximately 0.85mm of lengthening per 1° of DFO correction when performing LOW, compared to 0.45mm of shortening per 1° correction for MCW osteotomies.

Background: Osteochondral allograft (OCA) transplantation is an important surgical technique for full-thickness chondral defects in the knee. For patients undergoing this procedure, topography matching between the donor and recipient sites is essential to limit premature wear of the OCA. Currently, there is no standardized process of donor and recipient graft matching. Purpose: To evaluate a novel topography matching technique for distal femoral condyle OCA transplantation using 3-dimensional (3D) laser scanning to create 3D-printed patient-specific instrumentation in a human cadaveric model. Study Design: Descriptive laboratory study. Methods: Human cadaveric distal femoral condyles (n = 12) underwent 3D laser scanning. An 18-mm circular osteochondral recipient defect was virtually created on the medial femoral condyle (MFC), and the position and orientation of the best topography-matched osteochondral graft from a paired donor lateral femoral condyle (LFC) were determined using an in silico analysis algorithm minimizing articular step-off distances between the edges of the graft and recipient defect. Distances between the entire surface of the OCA graft and the underneath surface of the MFC were evaluated as surface mismatch. Donor (LFC) and recipient (MFC) 3D-printed patient-specific guides were created based on 3D reconstructions of the scanned condyles. Through use of the guides, OCAs were harvested from the LFC and transplanted to the reamed recipient defect site (MFC). The post-OCA recipient condyles were laser scanned. The 360° articular step-off and cartilage topography mismatch were measured. Results: The mean cartilage step-off and graft surface mismatch for the in silico OCA transplant were 0.073 ± 0.029 mm (range, 0.005-0.113 mm) and 0.166 ± 0.039 mm (range, 0.120-0.243 mm), respectively. Comparatively, the cadaveric specimens postimplant had significantly larger step-off differences (0.173 ± 0.085 mm; range, 0.082-0.399 mm; P = .001) but equivalent graft surface topography matching (0.181 ± 0.080 mm; range, 0.087-0.396 mm; P = .678). All 12 OCA transplants had mean circumferential step-off differences less than a clinically significant cutoff of 0.5 mm. Conclusion: These findings suggest that the use of 3D-printed patient-specific guides for OCA transplantation has the ability to reliably optimize cartilage topography matching for LFC to MFC transplantation. This study demonstrated substantially lower step-off values compared with previous orthopaedic literature when also evaluating LFC to MFC transplantation. Using this novel technique in a model performing MFC to MFC transplantation has the potential to yield further enhanced results due to improved radii of curvature matching. Clinical Relevance: Topography-matched graft implantation for focal chondral defects of the knee in patients improves surface matching and has the potential to improve long-term outcomes. Efficient selection of the allograft also allows improved availability of the limited allograft sources.

Background: All-suture anchors and knotless anchors are increasingly used in the repair of anteroinferior labral tears in patients with shoulder instability. Optimal repair constructs may limit recurrent instability. Purpose: To perform a quantitative biomechanical comparison of 3 labral fixation devices for soft tissue Bankart lesions: knotless soft-body tensionable anchor (SB knotless), knotted soft-body anchor (SB knotted), and knotless hard-body PEEK (polyether ether ketone) interference anchor (HB knotless). Study Design: Controlled laboratory study. Methods: A total of 21 glenoid specimens were randomized into 3 groups: SB knotless, SB knotted, and HB knotless. Artificial Bankart lesions were created at the anteroinferior labrum. Anchors were placed at the 3:30, 4:30, and 5:30 clockface positions, and sutures were passed through 1 cm of tissue. Anchors were tested simultaneously as one construct by pulling capsular tissue connected to the anteroinferior quadrant. Cyclic loading (5-25 N, 100 cycles) was followed by load-to-failure testing (15 mm/min). Biomechanical testing variables were collected, and failure mechanisms were recorded per individual anchor. Results: There were no differences in baseline specimen characteristics. There was no difference in elongation during cyclic loading ( P = .40). The ultimate load to failure between SB knotless (309.7 ± 125.6 N), SB knotted (226.4 ± 34.8 N), and HB knotless (256.5 ± 90.5 N) did not significantly differ ( P = .25). Failure mechanisms differed among groups ( P = .008); mechanisms included anchor pullout (SB knotless: 33.3%; SB knotted: 23.8%; HB knotless: 28.6%), suture pull-through (SB knotless: 66.7%; SB knotted: 38.1%; HB knotless: 33.3%), and anchor fixation method failure, defined as knot failure for knotted anchors or locking mechanism failure for knotless anchors (SB knotless: 0.0%; SB knotted: 38.1%; HB knotless: 38.1%).) Conclusion: The SB knotless, SB knotted, and HB knotless labral fixation anchors studied exhibited comparable elongation during cyclic loading, stiffness, and ultimate loads to failure in a cadaveric model. However, the failure mechanisms significantly differed, as SB knotless anchors failed primarily from suture pull-through, while SB knotted and HB knotless anchors were subject to knot failure and locking mechanism failure, respectively. Clinical Relevance: These data support the benefit of SB knotless anchors for anteroinferior labral repair in limiting knot failure typically seen with knotted anchors, perhaps demonstrating that all-suture anchors may have better locking mechanism quality than their PEEK counterparts.