Surgical restabilization reduces the progression of post-traumatic osteoarthritis initiated by ACL rupture in mice.

OBJECTIVE: People who sustain joint injuries such as anterior cruciate ligament (ACL) rupture often develop post-traumatic osteoarthritis (PTOA). In human patients, ACL injuries are often treated with ACL reconstruction. However, it is still unclear how effective joint restabilization is for reducing the progression of PTOA. The goal of this study was to determine how surgical restabilization of a mouse knee joint following non-invasive ACL injury affects PTOA progression. DESIGN: In this study, 187 mice were subjected to non-invasive ACL injury or no injury. After injury, mice underwent restabilization surgery, sham surgery, or no surgery. Mice were then euthanized on day 14 or day 49 after injury/surgery. Functional analyses were performed at multiple time points to assess voluntary movement, gait, and pain. Knees were analyzed ex vivo with micro-computed tomography, RT-PCR, and whole-joint histology to assess articular cartilage degeneration, synovitis, and osteophyte formation. RESULTS: Both ACL injury and surgery resulted in loss of epiphyseal trabecular bone (-27-32%) and reduced voluntary movement at early time points. Joint restabilization successfully lowered OA score (-78% relative to injured at day 14, p < 0.0001), and synovitis scores (-37% relative to injured at day 14, p = 0.042), and diminished the formation of chondrophytes/osteophytes (-97% relative to injured at day 14, p < 0.001, -78% at day 49, p < 0.001). CONCLUSIONS: This study confirmed that surgical knee restabilization was effective at reducing articular cartilage degeneration and diminishing chondrophyte/osteophyte formation after ACL injury in mice, suggesting that these processes are largely driven by joint instability in this mouse model. However, restabilization was not able to mitigate the early inflammatory response and the loss of epiphyseal trabecular bone, indicating that these processes are independent of joint instability.

Second Extensor Compartment Entrapment in an Adult Following Distal Radius Fracture.

Extensor tendon entrapment in the presence of distal radius fracture is a known but relatively uncommon complication. Single tendon or entire compartment entrapment has been described through the literature in youths and adults. However these findings generally are limited to a certain age demographic or are found on advanced imaging but are unable to be confirmed intraoperatively. We describe to our knowledge the first known description of second extensor compartment entrapment in an adult seen on computerized tomography scan and confirmed intraoperatively.

Posterior cruciate ligament retention with medial ball-in-socket conformity promotes internal tibial rotation and knee flexion while providing high clinical outcome scores.

BACKGROUND: Although retaining the posterior cruciate ligament (PCL) is advantageous in unrestricted kinematically aligned TKA, it is often excised with a medial stabilized implant. The primary objectives were to determine whether PCL retention using an insert with ball-in-socket (B-in-S) medial conformity to maximize A-P stability promotes internal tibial rotation and flexion while providing high patient-reported outcome scores. METHODS: Two cohorts of 25 patients each were treated with unrestricted kinematically aligned (KA) TKA using a tibial insert with B-in-S medial conformity and a flat lateral articular surface. One cohort retained the PCL; the other had it excised. Patients performed deep knee bend and step-up exercises during fluoroscopic imaging. Following 3D model-to-2D image registration, anterior-posterior (A-P) positions of the femoral condyles and tibial rotation were determined. RESULTS: For deep knee bend, mean internal tibial rotation with PCL retention was significantly greater at maximum flexion (17.7° ± 5.7° versus 10.4° ± 6.5°, p < 0.001) and significantly greater at 30°, 60°, and 90° flexion as well (p ≤ 0.0283). For step-up, mean internal tibial rotation with PCL retention was significantly greater at at 15°, 30°, and 45° flexion (p ≤ 0.0049) but was marginally not significantly greater at 60° (i.e. maximum) flexion (12.3° ± 4.4° versus 10.1° ± 5.4°, p = 0.0794). Mean flexion during active knee flexion with PCL retention was significantly greater (127° ± 8° versus 122° ± 6°, p = 0.0400). Both cohorts had high median Oxford Knee, WOMAC, and Forgotten Joint Scores that were not significantly different (p = 0.0918, 0.1448, and 0.0855, respectively) CONCLUSION: Surgeons that perform unrestricted KA TKA should retain the PCL with an insert that has B-in-S medial conformity, as this maintains extension and flexion gaps while also promoting internal tibial rotation and knee flexion as well as providing high clinical outcome scores.

Survivorship and Etiologies of Failure in Single-stage Revision Arthroplasty for Periprosthetic Joint Infection: A Meta-analysis.

INTRODUCTION: Single-stage revision arthroplasty for periprosthetic joint infection (PJI) may yield comparable infection-free survivorship with two-stage revision arthroplasty. It is unclear if the most common mode of failure of single-stage revision arthroplasty is infection or aseptic loosening. In this meta-analysis, we sought to (1) determine survivorship and (2) compare rates of different etiologies of failure of single-stage revision total hip arthroplasty (THA) and total knee arthroplasty (TKA). METHODS: Preferred Reporting Items for Systematic Review and Meta-analyses guidelines search was done using search terms for "single stage revision," "exchange arthroplasty," "periprosthetic infection," "PJI," and "single stage." Patient demographics such as age, body mass index, and mean follow-up time were recorded. Overall survivorship and rates of revision surgery were aggregated using a random-effects model. Comparison of septic and aseptic loosening rates was done by risk difference and associated 95% confidence interval (CI) calculation. RESULTS: Twenty-four studies were identified with 2,062 and 147 single-stage revision THA and TKA procedures performed between 1984 and 2019, respectively. The weighted mean follow-up and age were 69.8 months and 66.3 years, respectively, with 55% men overall. The all-cause revision surgery rate was 11.1% and 11.8% for THA and TKA, respectively. The revision surgery rate secondary to infection and aseptic loosening and associated 95% CI for the risk difference for THA and TKA was 5.5% and 3.3% (-1.7% to 5.0%), and 3% and 8.8% (-11.4% to 2.3%), respectively. Revision surgeries due to instability and fracture combined and mortality rate were both less than 3%. DISCUSSION: Single-stage revision THA and TKA for PJI demonstrated overall high rates of survivorship, low mortality, and revision surgeries secondary to infection and aseptic loosening to be equivalent. Aseptic loosening after single-stage revision TKA might be higher than in primary TKA. As implant survivorship from infection improves in PJI, surgeons should be aware of aseptic loosening as an equally common mode of failure.

Tantalum Cementless Versus Cemented Total Knee Arthroplasty: A Meta-analysis of Level 1 Studies.

INTRODUCTION: Controversy exists on the ideal type of fixation in total knee arthroplasty (TKA). Noncemented fixation has been theorized to improve patient outcomes and longevity of implantation without increased risk of aseptic loosening or radiolucent lines. We sought to compare (1) patient-reported outcomes, (2) survivorship, and (3) revision rates for all-cause and aseptic loosening in a noncemented tantalum total knee with its cemented counterpart. METHODS: Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines were searched using a combination of keywords "trabecular metal," "tantalum knee," "total knee arthroplasty," and "cementless trabecular." Patient demographics such as age, sex, and body mass index were collected. Outcomes such as Knee Society Scores (KSSs), revisions, and radiolucent lines were recorded for analysis. RESULTS: Four randomized controlled trials involving 507 patients with an average 5-year follow-up were eligible for meta-analysis. No differences were observed in any demographics such as age, sex, body mass index, nor preoperative KSS. Patients in the cemented cohort improved from preoperative KSS 46.4 to postoperative KSS 90.4 while the tantalum cohort improved from 46.4 to 89.3. No statistical difference was observed in postoperative KSS mean difference between groups. Six patients from the tantalum group underwent revision with one patient for aseptic loosening. Twelve patients from the cemented group underwent revision with four patients for aseptic loosening. No statistical difference was observed between rates of revision, aseptic loosening, or radiolucent line development. DISCUSSION: Patient-reported outcomes improved postoperatively in both groups. No differences were detected between the cemented and noncemented TKAs in patient-reported outcomes, revision rates, or radiolucent line development. Noncemented tantalum fixation seems equivalent to cemented TKA survivorship. Longer term follow-up of these randomized controlled trials may provide a clearer understanding whether a difference exists.

Improving Technical Outcome in Osteochondral Allograft Transplantation of the Femoral Trochlea: The Role of Contoured Guides, Experience Level, Graft Size, and Graft Position.

Background: The use of coring instrumentation for osteochondral allograft (OCA) transplantation of the femoral trochlea is challenging due to the complex topography of this anatomical area. Purpose: We sought to determine the effect of flat guides versus guides contoured to the surface of the trochlea on graft step-off in trochlear OCAs performed on a foam bone model. We also determined the effect of surgeon experience level and graft size on step-off. Study Design: Controlled laboratory study. Methods: Allograft harvesters were produced in 3 different sequential sizes with either a flat or a contoured undersurface. The guides matched one another in all aspects of shape and size except for the undersurface contour. The contoured undersurface generally matched the surface of the bone model trochlea but was not customized to that surface. A total of 72 foam femora were obtained. Identical trochlear stellate lesions of 3 different sizes (small, medium, and large) were created using 3-dimensional printed surface templates. A total of 6 surgeons (3 attending and 3 resident surgeons) performed OCAs of each trochlear lesion. Each surgeon performed 1 graft for each size and each guide type (n = 6 per surgeon). A specialized digital caliper was prepared that allowed the measurement of graft step-off to within 0.01 mm at a distance of 5 mm between the 2 sensors. The measurements were performed at 8 positions around the clockface of the grafts. Results: Grafts performed with the contoured guides had a mean step-off of 0.43 ± 0.37 mm. Grafts performed with the flat guides had a mean step-off of 0.74 ± 0.78 mm (P < .0001). Experience level did not have a significant effect on graft step-off (P = .81). There was no identifiable pattern indicating higher step-off at any one position on the clockface. Conclusion: In this study, contoured grafts had significantly lower step-offs compared with flat guides. Experience level, clockface position, and graft size did not affect step-off.

Loose Body Versus Trochlear Biopsy Matrix-Induced Autologous Chondrocyte Implantation (MACI) MOCART Scores and IKDC Reported Outcomes in Pediatric Patients.

BACKGROUND: Matrix-induced autologous chondrocyte implantation (MACI) has shown promising results in the treatment of osteochondral lesions of the knee. A recent study showed similar viability comparing chondrocytes harvested from the intercondylar notch compared to those harvested from osteochondral loose bodies. However, there is limited evidence assessing how these different biopsies perform clinically. The goal of this study was to compare both radiographic and patient-reported outcomes in patients with patellar and femoral osteochondral lesions treated with MACI using either a standard intercondylar notch biopsy or an osteochondral loose body biopsy. METHODS: A retrospective study was performed on all pediatric autologous chondrocyte implantation procedures performed from 2014 to 2017 at a single institution. Patients were divided into 2 groups: one group had cartilage derived from a standard intercondylar notch biopsy (n=9) and the other group had cartilage derived from an osteochondral loose body found within the ipsilateral knee (n=10). At a minimum of 1-year postimplantation, magnetic resonance imagings of the operative knee were performed and the Magnetic Resonance Observation of Cartilage Repair Tissue Knee Score (MOCART 2.0) knee score was used to assess the integrity and quality of the cartilage repair tissue. Interclass correlation coefficients were calculated between the 2 groups. International Knee Documentation Committee (IKDC) outcome scores were determined at a minimum 2 years post-implantation. RESULTS: The interclass correlation coefficient between three independent examiners for the MOCART scoring was excellent at 0.94. With regards to the MOCART score, the loose body group had an insignificant 17-point lower median score at 63 [interquartile range (IQR): 58 to 89] compared to the intercondylar group at 80 (IQR: 65 to 90) ( P =0.15). There was no difference in IKDC scores with the loose body group having a median score of 82 (IQR: 65 to 95) and the intercondylar group having a median score of 84 (IQR: 53 to 99) ( P =0.90). CONCLUSION: These results demonstrate that osteochondral loose bodies can be used as viable harvest site in MACI procedures with no difference in functional and radiographic outcomes at 2 years postimplantation. This may limit both short and long-term donor site morbidity. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

The posterolateral upslope of a low-conforming insert blocks the medial pivot during a deep knee bend in TKA: a comparative analysis of two implants with different insert conformities.

PURPOSE: Tibial insert conformity in total knee arthroplasty (TKA) is of interest due to the potential effect on tibiofemoral kinematics. This study determined differences in anterior-posterior movements of the femoral condyles, pivot locations, and internal tibial rotation in different arcs of flexion for two implants with different insert conformities in kinematically aligned TKA. METHODS: Twenty-five patients treated with a medial and lateral low-conforming, posterior cruciate ligament (PCL) retaining (LC CR) implant followed by a medial ball-in-socket and flat, lateral PCL sacrificing (B-in-S CS) implant in the contralateral knee underwent single-plane fluoroscopy during a deep knee bend. Analysis following 3D-to-2D image registration determined tibiofemoral kinematics and patients completed validated outcome scores for both knees. RESULTS: The mean follow-up of 1.6 ± 0.4 years for the knee with the B-in-S CS implant was shorter than the 2.7 ± 1.2 years for the LC CR implant. From 0º to 30º of flexion, a medial pivot occurred with the tibia rotating internally approximately 5º with both implants. From 30º to 90º, the pivot remained medial and internal rotation increased to 10º with the B-in-S CS implant. In contrast, neither femoral condyle moved more than 1 mm with the LC CR implant from 30º to 60º, but from 60º to 90º degrees, a lateral pivot occurred and internal rotation increased. Internal rotation of the tibia on the femur from 0° to maximum flexion occurred about a medial pivot similar to the native knee for the B-in-S CS implant and was 4.5° greater than that of the LC CR implant (10.4° vs 5.9°). There was no difference in the median patient-reported outcome scores between implant designs. CONCLUSIONS: Tibial insert conformity is a primary determinant of a medial or lateral pivot during a deep knee bend. One explanation for the transition from a medial to lateral pivot between 30º and 60º with the LC CR implant is the chock-block effect of the insert's posterolateral upslope which impedes posterior movement of the lateral femoral condyle. Because there is no posterolateral upslope in the insert of the B-in-S CS implant, the tibia pivots medially throughout flexion similar to the native knee. LEVEL OF EVIDENCE: Level III.

Posterior rim loading of a low-conforming tibial insert in unrestricted kinematic alignment is caused by rotational alignment of an asymmetric baseplate designed for mechanical alignment.

PURPOSE: Because different targets are used for internal-external rotation, an asymmetric baseplate designed for mechanical alignment may lead to under-coverage and concomitant posterior rim loading in the lateral compartment following unrestricted kinematic alignment (KA) TKA. Recognizing that such loading can lead to premature wear and/or subsidence, our aim was to determine the cause(s) so that occurrence could be remedied. Our hypothesis was that baseplate design features such as asymmetric shape when aligned in KA would consistently contribute to posterior rim loading in the lateral compartment. METHODS: Based on analysis of fluoroscopic images of 50 patients performing dynamic, weight bearing deep knee bend and step up and of postoperative CT images, five possible causes were investigated. Causes included internal rotation of the baseplate when positioned in KA; posterior position of the lateral femoral condyle at extension; internal tibial rotation with flexion; internal rotational deviation of the baseplate from the KA rotation target; and posterior slope. RESULTS: The incidence of posterior rim loading was 18% (9 of 50 patients). When positioned in KA, the asymmetric baseplate left 15% versus 10% of the AP depth of the lateral compartment uncovered posteriorly for posterior rim loading and non-posterior rim loading groups, respectively (p = 0.009). The lateral femoral condyle at extension was more posterior by 4 mm for the posterior rim loading group (p = 0.003). CONCLUSIONS: Posterior rim loading in the lateral compartment was caused in part by the asymmetric design of the tibial baseplate designed for mechanical alignment which was internally rotated when positioned in KA thus under-covering a substantial percentage of the posterior lateral tibia. This highlights the need for new, asymmetric baseplates designed to maximize coverage when used in KA. LEVEL OF EVIDENCE: III.

Traumatic Proximal Femoral Fractures during COVID-19 Pandemic in the US: An ACS NSQIP® Analysis.

In order to determine the impact of COVID-19 on the treatment and outcomes in patients with proximal femoral fracture's (PFF), we analyzed a national US sample. This is a retrospective review of American College of Surgery's (ACS) National Surgical Quality Improvement Program (NSQIP) for patients with proximal femoral fractures. A total of 26,830 and 26,300 patients sustaining PFF and undergoing surgical treatment were sampled during 2019 and 2020, respectively. On multivariable logistic regression, patients were less likely to have 'presence of non-healing wound' (p < 0.001), functional status 'independent' (p = 0.012), undergo surgical procedures of 'hemiarthroplasty'(p = 0.002) and 'ORIF IT, Peritroch, Subtroch with plates and screws' (p < 0.001) and to be 'alive at 30-days post-op' (p = 0.001) in 2020 as compared to 2019. Patients were more likely to have a case status 'emergent', 'loss of ≥10% body weight', discharge destination of 'home' (p < 0.001 for each) or 'leaving against medical advice' (p = 0.026), postoperative 'acute renal failure (ARF)' (p = 0.011), 'myocardial infarction (MI)' (p = 0.006), 'pulmonary embolism (PE)' (p = 0.047), and 'deep venous thrombosis (DVT)' (p = 0.049) in 2020 as compared to 2019. Patients sustaining PFF and undergoing surgical treatment during pandemic year 2020 differed significantly in preoperative characteristics and 30-day postoperative complications when compared to patients from the previous year.

Treatment of Dysplasia Epiphysealis Hemimelica with Autologous Chondrocyte Implantation: A Case Report.

Case: We present a case of dysplasia epiphysealis hemimelica (DEH) involving the posteromedial distal femur in a 4-year-old girl. The patient underwent lesion resection with internal fixation of the articular cartilage followed by autologous chondrocyte implantation (ACI) to restore the articular surface and epiphysis. At the 7-year follow-up, the patient had no pain or difficulty with participation in sports. Advanced imaging showed a stable articular surface with evidence of durable cartilage integration. Conclusion: DEH is a rare disease often treated by resection. In cases where the articular surface of the knee is involved, we have demonstrated that augmentation with ACI can be an effective treatment option.

Comparing Fusion Rates Between Fresh-Frozen and Freeze-Dried Allografts in Anterior Cervical Discectomy and Fusion.

Objective: The objective of this retrospective study is to compare the fusion rates in anterior cervical discectomy and fusion surgery using freeze-dried versus fresh-frozen allografts. Methods: The study comprised 79 patients. Fifty-one patients received freeze-dried allograft (106 total spinal levels) and 28 patients received fresh-frozen allograft (50 total spinal levels). Fusion was assessed through trabecular bridging on follow-up anterior-posterior/lateral radiographs. Trabecular bridging was assessed on the superior and inferior borders of each spinal level and given a fusion grade. Complete fusion is defined as >50% bridging between superior and inferior borders of the bone graft; union is complete fusion in <26 weeks; delayed union is complete fusion after 26 weeks; and fibrous union is <50% bridging at ≥1 borders over 52 weeks. Results: All spinal levels reached complete fusion for both graft types. Of the freeze-dried treated cervical spinal levels, 77.35% (82/106) reached union (adequate trabecular bridging within 6 months) without delay compared with 80% (35/50) for the fresh-frozen bone graft group (P = 0.85). There was no significant difference in time-to-fusion analysis and no significant association between delayed union and any patient factors. In assessing Neck Disability Index (NDI), freeze-dried allografts did show a significantly greater decrease in NDI scores at 6 months (P = 0.03). At the 1 year follow-up, improvements in NDI were consistent in both allografts (P = 0.9647). Conclusions: From this study, freeze-dried and fresh-frozen allografts showed comparable rates of union, and both allografts can be used interchangeably for anterior cervical discectomy and fusion.

Which Asymmetric Tibial Component Is Optimally Designed for Calipered Kinematically Aligned Total Knee Arthroplasty?

Calipered kinematically aligned (KA) total knee arthroplasty (TKA) restores the patient's prearthritic joint lines and sets internal-external rotation of the tibial component parallel to the flexion-extension (FE) plane, which is not a mechanical alignment (MA) target. Two asymmetric tibial components designed for MA set the tibial component to either a femoral component (FC) target or a tibial tubercle (TT) target. The study determined the optimal asymmetric tibial component to use with KA as the one with smaller IE deviation from the MA target, greater coverage of tibial resection, and lower incidence of cortical overhang. The study included 40 patients treated with bilateral calipered KA TKA with different asymmetric tibial components in opposite knees. A best-fit of a kinematic tibial template to the tibial resection set the template's slot parallel to the knee's FE plane. Each asymmetric tibial component's anterior-posterior (AP) axis was set parallel to the slot. Computer tomography analysis determined the IE deviation (-internal/+ external) of each tibial component from its MA target, tibial resection coverage by the baseplate and insert, and incidence of cortical overhang. The patient-reported Forgotten Joint Score (FJS) and Oxford Knee Score (OKS) determined outcomes. The mean IE deviation from the MA target was 2 degrees external for the FC-target asymmetric tibial component and -8 degrees internal for the TT-target asymmetric tibial component (p < 0.001). Tibial resection coverage by the baseplate (insert) was 88% (84%) for the FC target and 84% (79%) for the TT target (p < 0.001 for baseplate and insert). The FC target insert covered 3 mm more of the posterolateral resection (p < 0.001). Posteromedial coverage was comparable. The incidence of cortical overhang was 2.5% for each baseplate. There was no difference in FJS and OKS. When performing calipered KA, the more optimal design was the asymmetric tibial component with the FC target because of the smaller deviation from its MA target and the greater coverage of the tibial resection by the baseplate and insert.

CT scans better assess lateral wall morphology of "stable appearing" intertrochanteric (IT) femur fractures and predict early failure of sliding hip screw (SHS) fixation.

To compare the efficacy of plain x-ray images and computed tomography (CT) to assess the morphology of the lateral wall (LW) component of intertrochanteric (IT) femur fractures and determine predictors of early fixation failure. DESIGN: Retrospective cohort study. SETTING: Level-one trauma center. PATIENTS/PARTICIPANTS: One hundred forty-two adult patients with IT fractures treated with either a sliding hip screw (SHS) or a cephalomedullary nail (CMN) who had both pre-op plain x-ray images and CT scans with at least 6 weeks of follow-up were reviewed. INTERVENTION: Preoperative CT scan and plain radiographs of the affected hip. MAIN OUTCOME MEASUREMENTS: Lateral wall assessment based on plain x-rays versus CT imaging in relation to implant failure. RESULTS: One hundred forty-two patients met inclusion criteria, 105 patients treated with a CMN, and 37 with a SHS. There was a poor correlation between the assessment of the LW on plain x-ray images and CT scans. Failures in the SHS group were significantly associated with all CT measurements (P < .05) but not with plain film LW assessment (P = .66). Fifteen patients had an early implant failure (6 CMN, 9 SHS). There were no statistically significant associations between any radiographic measurement (plain images and CT) and CMN failures. CONCLUSIONS: Plain film images are not accurate for assessing lateral wall morphology/integrity and are not predictive of SHS implant failures. Our novel CT measurements were effective at detecting lateral wall patterns at risk for treatment failure with SHS implants.Level of Evidence: Level III.

Restoring the Patient's Pre-Arthritic Posterior Slope Is the Correct Target for Maximizing Internal Tibial Rotation When Implanting a PCL Retaining TKA with Calipered Kinematic Alignment.

INTRODUCTION: The calipered kinematically-aligned (KA) total knee arthroplasty (TKA) strives to restore the patient's individual pre-arthritic (i.e., native) posterior tibial slope when retaining the posterior cruciate ligament (PCL). Deviations from the patient's individual pre-arthritic posterior slope tighten and slacken the PCL in flexion that drives tibial rotation, and such a change might compromise passive internal tibial rotation and coupled patellofemoral kinematics. METHODS: Twenty-one patients were treated with a calipered KA TKA and a PCL retaining implant with a medial ball-in-socket and a lateral flat articular insert conformity that mimics the native (i.e., healthy) knee. The slope of the tibial resection was set parallel to the medial joint line by adjusting the plane of an angel wing inserted in the tibial guide. Three trial inserts that matched and deviated 2°> and 2°< from the patient's pre-arthritic slope were 3D printed with goniometric markings. The goniometer measured the orientation of the tibia (i.e., trial insert) relative to the femoral component. RESULTS: There was no difference between the radiographic preoperative and postoperative tibial slope (0.7 ± 3.2°, NS). From extension to 90° flexion, the mean passive internal tibial rotation with the pre-arthritic slope insert of 19° was greater than the 15° for the 2°> slope (p < 0.000), and 15° for the 2°< slope (p < 0.000). DISCUSSION: When performing a calipered KA TKA with PCL retention, the correct target for setting the tibial component is the patient's individual pre-arthritic slope within a tolerance of ±2°, as this target resulted in a 15-19° range of internal tibial rotation that is comparable to the 15-18° range reported for the native knee from extension to 90° flexion.

Editorial Commentary: Drill and Fill: Bone Marrow Stimulation Plus Allograft Matrix May Optimize the Treatment of Osteochondral Lesions of the Talus.

Osteochondral lesions of the talus remain a challenging pathologic entity facing orthopaedic foot and ankle surgeons. Although multiple treatment options exist, there is limited evidence supporting one technique over another. The ultimate goal of surgical intervention is to achieve lesion infill with tissue properties that best mimic those of hyaline articular cartilage. Restoring the anatomic surface of the talus may provide long-term clinical success and improve function. Augmentation of bone marrow stimulation with extracellular matrix cartilage allograft aims to achieve this goal.

The Biomechanical Effects of Simulated Radioscapholunate Fusion With Distal Scaphoidectomy, 4-Corner Fusion With Complete Scaphoidectomy, and Proximal Row Carpectomy Compared to the Native Wrist.

PURPOSE: To determine the effect of simulated radioscapholunate fusion with distal scaphoid excision (RSLF+DSE), 4-corner fusion with scaphoidectomy (4-CF), and proximal row carpectomy (PRC) on the wrist's range of motion (ROM), contact pressure, and contact force in a cadaveric model. METHODS: Ten freshly frozen cadaveric wrists were tested under 4 sequential conditions: native wrist, RSLF+DSE, 4-CF, and PRC. The simulated fusions were performed using two 1.6-mm Kirschner wires. The ROM in the flexion-extension and radioulnar deviation planes was evaluated. Contact area, contact pressure, and contact force were measured at the scaphocapitolunate joint for the RSLF+DSE simulation and radiocarpal joint for the 4-CF and PRC simulations. Mechanical testing was performed using a 35-N uniaxial load and pressure-sensitive film. RESULTS: The RSLF+DSE and 4-CF groups had a decreased wrist arc ROM compared with the native wrist. The PRC group had a greater wrist arc ROM compared with the RSLF+DSE and 4-CF groups, but compared to the native wrist, it demonstrated a mildly decreased wrist arc ROM. The carpal pressure and contact force were significantly increased in the RSLF+DSE, 4-CF, and PRC groups compared with those in the native wrist. The RSLF+DSE group had the smallest increase in the carpal pressure and contact force, whereas the PRC group had the greatest increase. CONCLUSIONS: Our study validates previous findings that PRC is motion-conserving but has the greatest contact force, whereas RSLF-DSE and 4-CF may cause a decrease in the ROM but have lower contact forces. CLINICAL RELEVANCE: Understanding the underlying native wrist biomechanics and alterations following different surgical treatments may assist hand surgeons in their clinical decision making for the treatment of stage II scapholunate advanced collapse.

Osteoporosis Is Undertreated After Low-energy Vertebral Compression Fractures.

INTRODUCTION: Despite guidelines recommending postfracture bone health workup, multiple studies have shown that evaluation and treatment of osteoporosis has not been consistently implemented after fragility fractures. The primary aim of this study was to evaluate rates of osteoporosis evaluation and treatment in adult patients after low-energy thoracolumbar vertebral compression fractures (VCFs). METHODS: We retrospectively reviewed all patients ≥60 years old presenting to a single academic trauma center with acute thoracolumbar VCFs after a ground-level fall from 2016 to 2020 . Rates of osteoporosis screening with dual-energy x-ray absorptiometry and initiation of pharmaceutical treatment were recorded at four time points: before the date of injury, during index hospitalization, at first primary care provider follow-up, and at final primary care provider follow-up. Rates of subsequent falls and secondary fragility fractures were recorded. One-year mortality and overall mortality were also calculated. RESULTS: Fifty-two patients with a mean age of 83 years presenting with thoracic and/or lumbar fractures after a ground-level fall were included. At a mean final follow-up of 502 days, only 10 patients (19.2%) received pharmacologic therapy for osteoporosis and only 6 (11.5%) underwent postinjury dual-energy x-ray absorptiometry evaluation. Twenty-five patients (48%) had at least one subsequent fall at a mean of 164 days from the initial date of injury. Eleven patients with subsequent falls sustained an additional fragility fracture because of the fall, including six operative injuries. One-year mortality among the 52 patients was 26.9%, and the overall mortality rate was 44.2% at the final follow-up. DISCUSSION: Osteoporosis remains a major public health issue that markedly affects quality of life and healthcare costs. Our study demonstrates the additional need for improved osteoporosis workup and intervention among patients who have sustained VCFs. We hope that our study helps raise awareness for improved osteoporosis evaluation and treatment among spine surgeons and all medical professionals treating patients with fragility fractures. LEVEL OF EVIDENCE: Retrospective Case Series, Level IV Evidence.

Aging Decreases the Ultimate Tensile Strength of Bone-Patellar Tendon-Bone Allografts.

PURPOSE: The purpose of this study was to determine whether aging imparts a clinically significant effect on the (1) mechanism of graft failure and (2) structural, material, and viscoelastic properties of patellar tendon allografts by evaluating these properties in younger donors (≤30 years of age) and older donors (>50 years of age). METHODS: A total of 34 younger (≤30 years of age) and 34 older (>50 years of age) nonirradiated, whole bone-tendon-bone allografts were prepared for testing by isolating the central third of the patellar tendon using a double-bladed 10-mm width scalpel under a 10-N load to ensure uniformity of harvest. Bone blocks were potted in polymethylmethacrylate within custom molds. Tendon length and cross-sectional area were measured using an area micrometer. A mechanical loading system was used to precondition the grafts for 100 cycles with a load between 50 N and 250 N (1 Hz). A creep load (500 N) was then applied at a rate of 100 mm/min (10 minutes). Grafts were allowed to recover at 1 N (10 minutes), followed by pull-to-failure at a rate of 100% strain per second. Mechanisms of failure (midsubstance vs avulsion) were noted and the structural, material, and viscoelastic properties calculated and compared between groups. RESULTS: There were 33 (97%) midsubstance tears in the younger group and 28 (82%) in the older group (P = .034). Younger grafts showed greater ultimate load to failure (1,782 N [1,533, 2,032] vs 1,319 N [1,103, 1,533]) (P = .006) and ultimate tensile stress (37.4 MPa [32.4, 42.4] vs 27.5 MPa [22.9, 32.0]) (P = .006). There were no significant differences in displacement (P = .595), stiffness (P = .950), strain (P = .783), elastic modulus (P = .114), creep displacement (P = .881), and creep strain (P = .614). CONCLUSIONS: This in vitro study suggests that aging weakens the bone-tendon junction and decreases the ultimate tensile strength of patellar tendon allografts. However, aging did not affect the displacement, strain, stiffness, elastic modulus, creep displacement, or creep strain of patellar tendon allografts. CLINICAL RELEVANCE: Surgeons should be aware that patellar tendon allografts from donors >50 years of age have a lower ultimate tensile stress than donors ≤30 years of age.

Anterior and Posterior Fusion for Large, Rigid Idiopathic Scoliosis: Does Implant Density Matter?

BACKGROUND: Despite advancements in surgical techniques, controversy remains regarding the optimal implant density for the correction of idiopathic scoliosis. Recent evidence has suggested that equivalent radiographic and clinical outcomes can be achieved with lower implant densities for those with moderate curves and good flexibility. Among the experts, the consensus has continued that higher implant densities should be used for larger, stiffer curves. The purpose of the present study was to compare the radiographic results between high-implant density (HID) and low-implant density (LID) constructs in patients with large (>65°), rigid (<50% flexibility) curves who had undergone anterior release and posterior spinal fusion. METHODS: We reviewed the idiopathic scoliosis cases performed at a single institution from 2006 to 2014. Only those meeting the inclusion criteria were selected. The patients were divided into HID and LID groups. The postoperative radiographs were compared for coronal correction, thoracic kyphosis, pelvic tilt, lumbar lordosis, and sagittal vertical axis. RESULTS: A statistically significant improvement in coronal correction was detected in the HID group at all follow-up points (final follow-up: HID, 81.1% vs. LID, 70.4%; P = 0.01). When preoperative thoracic kyphosis was considered, no differences were found between the 2 groups. No differences were found in the other sagittal parameters. CONCLUSION: In patients with large, rigid idiopathic scoliosis undergoing anterior release and posterior spinal fusion, a small, but statistically, significant improvement in the coronal Cobb angle was seen. It remains to be determined whether this small difference in radiographic correction will have any influence on the clinical outcome.