Non-anatomical reconstruction of chronic posterolateral corner knee injuries show failure rates from 0% to 36% versus 4.3% to 24.2% for anatomic reconstruction techniques: An updated systematic review reflecting the 2019 expert consensus statement.

OBJECTIVE: To review and update the literature regarding outcomes following surgical management of chronic, grade III posterolateral corner (PLC) injuries, with an emphasis on estimating failure rates based upon objective parameters in light of the 2019 expert consensus, while secondarily comparing the failure rates of anatomic versus non-anatomic reconstruction techniques. METHODS: A literature search was performed using the PubMed, Embase, MEDLINE, and Cochrane Library databases. Inclusion criteria consisted of level I-IV human clinical studies reporting subjective and objective outcomes in patients following surgical management for chronic (>6 weeks from injury) grade III PLC injuries, with a minimum two-year follow-up. The criterion for objective surgical failure was based on post-operative varus stress radiographs and defined as a side-to-side difference of 3 â€‹mm or more of lateral gapping. RESULTS: A total of six studies, consisting of 10 separate cohorts encompassing a total of 230 patients, were identified. PLC reconstruction was performed in all cohorts, with 80 â€‹% (n â€‹= â€‹8/10) of these cohorts utilising an anatomic reconstruction technique. A failure rate ranging from 4.3 â€‹% to 36 â€‹% was found. Subgroup analysis revealed a failure rate of 4.3 â€‹%-24.2 â€‹% for anatomic reconstruction techniques, whereas a 0 â€‹%-36 â€‹% failure rate was found for non-anatomic reconstruction. Arthrofibrosis was the most common complication (range, 0 â€‹%-12.1 â€‹%) following surgery. 0 â€‹%-8 â€‹% of patients required revision PLC surgery. CONCLUSION: PLC reconstruction yields a wide variability in failure rates according to the side-to-side difference of 3 â€‹mm or more of lateral gapping on post-operative varus stress radiographs, with low revision rates following anatomic and non-anatomic reconstruction techniques. LEVEL OF EVIDENCE: IV; Systematic Review of Level III and IV studies.

Systematic Review and Meta-analysis of Studies Comparing Complete Capsular Closure Against Unrepaired Hip Capsules During Hip Arthroscopy.

Background: While the biomechanical importance of the hip capsule is well described, there remains controversy over the necessity of routine capsular closure after hip arthroscopy. Purpose: To perform a meta-analysis of clinical studies to compare pooled outcomes of complete hip capsular closure cohorts against unrepaired hip capsule cohorts. Study Design: Systematic review; Level of evidence, 3. Methods: The Cochrane Database of Systematic Reviews, Cochrane Register of Controlled Trials, PubMed, MEDLINE, Web of Science, CINAHL/EBSCO, and Scopus were queried in February 2022 for studies that directly compared clinical outcomes for hip arthroscopy patients treated with either complete capsular closure or an unrepaired capsule. Outcomes assessed were incidence of revision hip arthroscopy, incidence of subsequent conversion to total hip arthroplasty (THA), and improvement from baseline in modified Harris Hip Score (mHHS), Hip Outcome Score (HOS) activities of daily living (ADL), HOS sports specific (SS) subscale, Copenhagen Hip and Groin Outcome Score (HAGOS) ADL, and HAGOS SS subscale. A pooled weighted mean difference (WMD) was used to compare changes in mHHS. A pooled standardized mean difference (SMD) was used to compare changes in the ADL and SS outcomes. A pooled risk ratio (RR) was used to compare the probability of revision hip arthroscopy and conversion to THA based on capsular management. For pooled outcomes where heterogeneity was regarded as potentially unimportant, a fixed-effects model was implemented. For pooled outcomes with considerable heterogeneity, a random-effects model was implemented. Results: Of the 1896 records identified in our search, 11 studies (1897 patients) were included. A significantly higher improvement in mHHS (WMD, -3.72; 95% CI, -4.95 to -2.50; P < .00001) and ADL outcomes (SMD, -0.30; 95% CI, -0.54 to -0.07; P = .01) were seen after complete capsular closure. There was a significantly lower probability of subsequent revision hip arthroscopy (RR, 1.67; 95% CI, 1.14 to 2.45; P = .008) and conversion to THA (RR, 2.01; 95% CI, 1.06 to 3.79; P = .03) after complete capsular repair. There was no difference in SS outcomes (SMD, -0.02; 95% CI, -0.16 to 0.13; P = .81) between the 2 groups. Conclusion: This meta-analysis demonstrated that routine complete capsular closure after hip arthroscopy led to superior clinical outcomes relative to unrepaired hip capsules.

Medial Collateral Ligament Reconstruction and Repair Show Similar Improvement in Outcome Scores, But Repair Shows Higher Rates of Knee Stiffness and Failure: A Systematic Review.

PURPOSE: To compare patient-reported outcomes and complications in patients with medial collateral ligament (MCL) injuries undergoing repair versus reconstruction with a minimum 2-year follow-up. METHODS: A literature search was conducted using the PubMed, Scopus, and Embase-computerized databases from database inception to November 2022, according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies evaluating clinical outcomes and complications at a minimum of 2 years following MCL repair versus reconstruction were included. Study quality was assessed using the MINORS criteria. RESULTS: A total of 18 studies published from 1997 to 2022, consisting of 503 patients were identified. Twelve studies (n = 308 patients; mean age: 32.6 years) reported outcomes following MCL reconstruction, and 8 studies (n = 195 patients; mean age: 28.5 years) reported results following MCL repair. Postoperative International Knee Documentation Committee, Lysholm, and Tegner scores ranged from 67.6 to 91, 75.8 to 94.8, and 4.4 to 8, respectively, in the MCL reconstruction group, compared to 73 to 91, 75.1 to 98.5, and 5.2 to 10, respectively, in the MCL repair group. Knee stiffness was the most commonly reported complication following MCL repair (range: 0% - 50%) and reconstruction (range: 0% - 26.7%). Failures occurred in 0% to 14.6% of patients following reconstruction versus 0% to 35.1% of patients undergoing MCL repair. Manipulation under anesthesia (MUA) for postoperative arthrofibrosis (range: 0% - 12.2%) and surgical debridement for arthrofibrosis (range: 0% - 20%) were the most commonly reported reoperations in the MCL reconstruction and repair groups, respectively. CONCLUSIONS: MCL reconstruction versus repair both demonstrate improved International Knee Documentation Committee, Lysholm, and Tegner scores. MCL repair demonstrates higher rates of postoperative knee stiffness and failure at a minimum 2-year follow-up. LEVEL OF EVIDENCE: Level IV, systematic review of Level III and IV studies.

Acellular Dermal Allograft and Tensor Fascia Lata Autograft Show Similar Patient Outcome Improvement and High Rates of Complications and Failures at a Minimum 2-Year Follow-Up: A Systematic Review.

PURPOSE: To compare clinical and radiologic outcomes following superior capsular reconstruction (SCR) using dermal allograft versus tensor fascia lata (TFL) autograft for massive rotator cuff tears with a minimum 2-year follow-up. METHODS: A literature search was performed by querying Scopus, EMBASE, and PubMed computerized databases from database inception through September 2022 in accordance with the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies evaluating clinical and radiologic outcomes, as well as complications following SCR for the treatment of massive rotator cuff tears were included. Study quality was assessed via the Newcastle-Ottawa Scale and the National Institutes of Health Quality Assessment. The mean change from preoperative to postoperative values (delta) was calculated for each outcome. RESULTS: Seventeen studies, consisting of 519 patients were identified. Mean duration of follow-up ranged from 24 to 60 months. Mean reduction in visual analog scale pain score ranged from 2.9 to 5.9 points following use of dermal allograft, and 3.4 to 7.0 points following TFL autograft reconstruction. Mean improvements in American Shoulder and Elbow Surgeons score were similar between groups (dermal allograft: 28.0-61.6; TFL autograft: 24.7-59.3). The mean increase in forward flexion ranged from 31° to 38° with dermal allograft, versus 19° to 69° with TFL autograft. Average improvement in active external rotation with dermal allograft ranged from -0.4° to 11° and from 2° to 22.4° using TFL autograft. A similar change in acromiohumeral distance following SCR (dermal allograft: 0.9-3.2 mm; TFL autograft: 0.3-3.6 mm) was appreciated. The rate of complications within the dermal allograft group ranged from 4.5% to 38.2% versus 13.3% to 86.4% following TFL autograft. Failure rate ranged from 4.5 to 38.2% following dermal allograft versus 4.5 to 86.4% with TFL autograft. CONCLUSIONS: Acellular dermal allograft versus TFL autograft for SCR both demonstrate improved VAS and American Shoulder and Elbow Surgeons scores, with increased values in flexion and external rotation, and increased visual analog scale, although with high variability. Both grafts demonstrate high rates of complications and failures at minimum 2-year follow-up. LEVEL OF EVIDENCE: IV; systematic review of level II-IV studies.

A Comprehensive Meta-analysis of Clinical and Biomechanical Outcomes Comparing Double-Bundle and Single-Bundle Posterior Cruciate Ligament Reconstruction Techniques.

BACKGROUND: Posterior cruciate ligament (PCL) reconstruction techniques have historically focused on single-bundle (SB) reconstruction of the larger anterolateral bundle without addressing the codominant posteromedial bundle. The SB technique has been associated with residual laxity and instability, leading to the development of double-bundle (DB) reconstruction techniques. PURPOSE: To perform a meta-analysis of comparative clinical and biomechanical studies to differentiate the pooled outcomes of SB and DB PCL reconstruction cohorts. STUDY DESIGN: Meta-analysis and systematic review: Level of evidence, 3. METHODS: Six databases were queried in February 2022 for literature directly comparing clinical and biomechanical outcomes for patients or cadaveric specimens undergoing DB PCL reconstruction against SB PCL reconstruction. Biomechanical outcomes included posterior tibial translational laxity, external rotational laxity, and varus laxity at 30° and 90° of knee flexion. Clinical outcomes included the side-to-side difference in posterior tibial translation during postoperative stress radiographs, risk of a major complication, and the following postoperative patient-reported outcome measures: Lysholm, Tegner, and International Knee Documentation Committee (IKDC) subjective and objective scores. A random-effects model was used to compare pooled clinical and biomechanical outcomes between the cohorts. RESULTS: Fifteen biomechanical studies and 13 clinical studies were included in this meta-analysis. The DB group demonstrated significantly less posterior tibial translation at 30° and 90° of knee flexion (P < .00001). Additionally, the DB group demonstrated significantly less external rotation laxity at 90° of knee flexion (P = .0002) but not at 30° of knee flexion (P = .33). There was no difference in varus laxity between the groups at 30° (P = .56) or 90° (P = .24) of knee flexion. There was significantly less translation on stress radiographs in the DB group (P = .02). Clinically, there was no significant difference between the groups for the Lysholm score (P = .95), Tegner score (P = .14), or risk of a major complication (P = .93). DB PCL reconstruction led to significantly higher odds of achieving "normal" or "near normal" objective IKDC outcomes for the included prospective studies (P = .04) and higher subjective IKDC scores (P = .01). CONCLUSION: DB PCL reconstruction leads to superior biomechanical outcomes and clinical outcomes relative to SB PCL reconstruction. Re-creating native anatomy during PCL reconstruction maximizes biomechanical stability and clinical outcomes.

Development of a Coarse-Grained Model of Collagen-Like Peptide (CLP) for Studies of CLP Triple Helix Melting.

In this paper, we present the development of a phenomenological coarse-grained model that represents single strands of collagen-like peptides (CLPs) as well as CLP triple helices. The goal of this model development is to enable coarse-grained molecular simulations of solutions of CLPs and conjugates of CLPs with other macromolecules and to predict trends in the CLP melting temperature with varying CLP design, namely CLP length and composition. Since the CLP triple helix is stabilized primarily by hydrogen bonds between amino acids in adjacent strands, for modeling CLP melting we get inspiration from a recent coarse-grained (CG) model that was used to capture specific and directional hydrogen-bonding interactions in base-pair hybridization within oligonucleotides and reproduced known DNA melting trends with DNA sequence and composition in implicit water. In this paper, we systematically describe the changes we make to this original CG model and then show that these improvements reproduce the known melting trends of CLPs seen in past experiments. Specifically, the CG simulations of CLP solutions at experimentally relevant concentrations show increasing melting temperature with increasing CLP length and decreasing melting temperature with incorporation of charged residues in place of uncharged residues in the CLP, in agreement with past experimental observations. Finally, results from simulations of CLP triple helices conjugated with elastin like peptides (ELPs), using this new CG model of CLP, reproduce the same trends in ELP aggregation as seen in past experiments.

Effect of oligonucleic acid (ONA) backbone features on assembly of ONA-star polymer conjugates: a coarse-grained molecular simulation study.

Understanding the impact of incorporating new physical and chemical features in oligomeric DNA mimics, termed generally as "oligonucleic acids" (ONAs), on their structure and thermodynamics will be beneficial in designing novel materials for a variety of applications. In this work, we conduct coarse-grained molecular simulations of ONA-star polymer conjugates with varying ONA backbone flexibility, ONA backbone charge, and number of arms in the star polymer at a constant ONA strand volume fraction to elucidate the effect of these design parameters on the thermodynamics and assembly of multi-arm ONA-star polymer conjugates. We quantify the thermo-reversible behavior of the ONA-star polymer conjugates by quantifying the hybridization of the ONA strands in the system as a function of temperature (i.e. melting curve). Additionally, we characterize the assembly of the ONA-star polymer conjugates by tracking cluster formation and percolation as a function of temperature, as well as cluster size distribution at temperatures near the assembly transition region. The key results are as follows. The melting temperature (Tm) of the ONA strands decreases upon going from a neutral to a charged ONA backbone and upon increasing flexibility of the ONA backbone. Similar behavior is seen for the assembly transition temperature (Ta) with varying ONA backbone charge and flexibility. While the number of arms in the ONA-star polymer conjugate has a negligible effect on the ONA Tm in these systems, as the number of ONA-star polymer arms increase, the assembly temperature Ta increases and local ordering in the assembled state improves. By understanding how factors like ONA backbone charge, backbone flexibility, and ONA-star polymer conjugate architecture impact the behavior of ONA-star polymer conjugate systems, we can better inform how the selection of ONA chemistry will influence resulting ONA-star polymer assembly.

Effect of conjugation on phase transitions in thermoresponsive polymers: an atomistic and coarse-grained simulation study.

Using atomistic and coarse-grained molecular dynamics (MD) simulations, we explain the shifts in lower critical solution temperature (LCST)-like phase transitions exhibited by elastin-like peptides (ELPs) upon conjugation to other macromolecules (e.g. collagen-like peptides or CLPs). First, using atomistic simulations, we study ELP oligomers with the sequence (VPGFG)6 in explicit water, and characterize the LCST-like transition temperature as one at which the ELP oligomers undergo a change in "hydration state". In agreement with past experimental observations of Luo and Kiick, upon anchoring ELP oligomers to a point to mimic ELP oligomers conjugated to another macromolecule, there is an apparent slight shift in the transition temperature to lower values compared to free (unconjugated) ELP oligomers. However, these atomistic simulations are limited to small systems of short ELPs, and as such do not capture the multiple chain aggregation/phase separation observed in experiments of ELPs. Therefore, we utilize phenomenological coarse-grained (CG) MD simulations to probe how conjugating a block of generic-LCST polymer to another rigid unresponsive macromolecular block impacts the transition temperatures at concentrations and length scales larger than atomistic simulations. We find that when multiple LCST polymer chains are conjugated to a rigid unresponsive polymer block, the increased local crowding of the LCST polymers shifts the transition marked by onset of chain aggregation to smaller effective polymer-polymer attraction energies compared to the free LCST polymer chains. The driving force needed for aggregation is reduced in the conjugates compared to free LCST polymer due to reduction in the loss of polymer configurational entropy upon aggregation.