Use of a Novel Reverse Hip Replacement System to Address Dislocation and Instability.

While total hip arthroplasty (THA) is an enormously successful treatment for patients with end-stage degenerative arthritis of the hip, and surgeons have optimized existing hip implants and techniques, dislocation and instability persist as a leading cause of failure. Given the tremendous success of reverse total shoulder arthroplasty in enhancing the stability of shoulder reconstruction by reversing the anatomic seating of the ball and socket components, one manufacturer (Hip Innovation Technology, LLC, Woodstock, Georgia) has developed a novel Reverse Hip Replacement System (Reverse HRS) to address the need for greater stability in reconstruction of the arthritic hip joint. Rather than the traditional anatomic components that replace the head of the femur with a spherical ball and the acetabulum with a socket with polyethylene liner mounted into the pelvis, the Reverse HRS features a cup with polyethylene liner attached to the femoral stem and a spherical metal head attached to a central trunnion inside of the porous-coated acetabular shell fixed into the pelvis. This design provides dramatically enhanced stability and improved range of motion. This article reviews relevant published literature, including results from a Canadian clinical trial and case reports from a multicenter American clinical trial monitored by the U.S. Food and Drug Administration. It also describes the components and surgical technique of reverse THA.

Retention of the posterior cruciate ligament stabilizes the medial femoral condyle during kneeling using a tibial insert with ball-in-socket medial conformity.

PURPOSE: Resecting the posterior cruciate ligament (PCL) increases posterior laxity and increases the flexion gap more than the extension gap in the native (i.e. healthy) knee. These two effects could lead to significant anterior displacement of the medial femoral condyle in kneeling following total knee arthroplasty even when using a tibial insert with a high degree of medial conformity. Using an insert with ball-in-socket medial conformity and a flat lateral articular surface, the primary purpose was to determine whether the medial femoral condyle remained stable with and without PCL retention during kneeling. METHODS: Two groups of patients were studied, one with PCL retention (22 patients) and the other with PCL resection (25 patients), while kneeling at 90º flexion. Following 3D model-to-2D image registration, A-P displacements of both femoral condyles were determined relative to the dwell point of the medial socket. RESULTS: With PCL resection versus PCL retention, the medial femoral condyle was 5.1 ± 3.7 mm versus 0.8 ± 2.1 mm anterior of the dwell point (p < 0.0001). Patient-reported function scores were comparable (p ≥ 0.1610) despite a significantly shorter follow-up of 7.8 ± 0.9 months with PCL retention than 19.6 ± 4.9 months with PCL resection (p < 0.0001). Range of motion was 126 ± 8° versus 122 ± 6° with and without PCL retention, respectively (p = 0.057). CONCLUSION: Surgeons that use a highly conforming tibial insert design can stabilize the medial femoral condyle during kneeling by retaining the PCL. In patients with PCL resection, the 9 mm high anterior lip of the insert with ball-in-socket medial conformity was insufficient to prevent significant anterior displacement of the medial femoral condyle when weight-bearing on the anterior tibia.

The Effect of Gracilis Tendon Preservation on Postoperative Knee Joint Stability and Muscle Strength in Arthroscopic Anterior Cruciate Ligament Reconstruction Surgery.

The aim of our study is to evaluate preserving gracilis tendon in anterior cruciate ligament reconstruction (ACLR) surgery and its effect to the flexion of the knee joint and tibial internal rotation strength and the stability of the knee. Patients who underwent primary single-bundle arthroscopic ACLR using all-inside technique and using hamstring tendon autograft were evaluated retrospectively. Patients were divided into two groups as gracilis preserved (St) and gracilis harvested (StG) groups. The International Knee Documentation Committee (IKDC) score, Lysholm, Knee Injury and Osteoarthritis Outcome Score-Knee-related quality of life (KOOS-QOL) score, ACL-Return to Sport after Injury scale score were used to evaluate as postoperative functional scores at last follow-up. Anterior tibial translation was evaluated using the KT-1000 device. Knee joint flexion, extension, and internal rotation strength were evaluated using isokinetic dynamometer. Dynamic balance performances were measured using the Biodex Balance System. There were 24 patients in the St group and 23 patients in the StG group. Demographic data and clinical results showed no significant difference. Anteroposterior movement of the tibia was found to be significantly higher in the StG group than in the St group in measurements at 89 and 134 N, respectively (p = 0.01 and <0.001). No statistically significant difference was found between both standard and deep flexor and extensor and internal rotator strength. No statistically significant difference was found in the amount of total, anteroposterior, and mediolateral balance deficit between the two groups. Additional gracilis harvesting does not have a negative effect on both standard and deep knee flexion, and tibial internal rotation strength compared with the St group. Although semitendinosus and StG group showed significantly more anterior tibial translation, there was no significant difference in clinical and dynamic stability measurements.

An anteromedial stabilization procedure has the most protective effect on the anterior cruciate ligament in tibial external rotation. A human knee model study.

INTRODUCTION: Anterior cruciate ligament (ACL) reconstruction remains associated with the risk of re-rupture and persisting rotational instability. Additional extraarticular anterolateral stabilization procedures stabilize the tibial internal rotation and lead to lower ACL failure rate and improved knee stability. However, data for additional stabilization of tibial external rotation is lacking and the importance of an anteromedial stabilization procedure is less well evaluated. Aim of this study is to investigate the influence of an extraarticular anteromedial stabilization procedure for the stabilization of the tibial external rotation and protection of the ACL from these rotational forces. METHODS: Internal and external rotations of the tibia were applied to a finite element (FE) model with anatomical ACL, posterior cruciate ligament (PCL), lateral collateral ligament (LCL), medial collateral ligament (MCL) and intact medial and lateral meniscus. Five additional anatomic structures (Anteromedial stabilization/anteromedial ligament, AML, augmented superficial medial collateral ligament, sMCL, posterior oblique ligament, POL, anterolateral ligament, ALL, and popliteal tendon, PLT) were added to the FE model separately and then combined. The force histories within all structures were measured and determined for each case. RESULTS: The anteromedial stabilization or imaginary AML was the main secondary stabilizer of tibial external rotation (90% of overall ACL force reduction). The AML reduced the load on the ACL by 9% in tibial external rotation which could not be achieved by an augmented sMCL (-1%). The AML had no influence in tibial internal rotation (-1%). In the combined measurements with all additional structures (AML, ALL, PLT, POL) the load on the ACL was reduced by 10% in tibial external rotation. CONCLUSION: This study showed that an additional anteromedial stabilization procedure secures the tibial external rotation and has the most protective effect on the ACL during these external rotational forces.

Strategies for knee stabilising and pivot-shift avoidance in a step-down and cross-over task observed sub-acutely after anterior cruciate ligament reconstruction.

BACKGROUND: Individuals with a recent anterior cruciate ligament reconstruction may demonstrate an altered movement strategy for protecting the knee and maintaining stability. Altered knee movement might lead to abnormal intra-articular load, potentially contributing to early knee osteoarthritis onset. A protective strategy may be particularly evident during active tasks that induce a pivot-shift manoeuvre, such as a step-down and cross-over task. In this study, we investigated whether knee joint mechanics and muscle activity differed between participants early (∼3 months) following reconstruction (n = 35) to uninjured controls (n = 35) during a step-down and cross-over task with a 45° change-of-direction. METHODS: We used motion capture, force plates and surface electromyography to compare time-normalised curves of sagittal and transverse-plane knee mechanics and muscle activity during the cross-over phase between groups using functional t-tests. We also compared knee mechanics between sides within the injured group and compared discrete outcomes describing the cross-over phase between groups. FINDINGS: Compared to controls, the injured participants had greater knee flexion angle and moment, lower internal rotation moment, more preparatory foot rotation of the pivoting leg, a smaller cross-over angle, and a longer cross-over phase for both the injured and uninjured sides. The injured leg also had greater biceps femoris and vastus medialis muscle activity compared to controls and different knee mechanics than the uninjured leg. INTERPRETATION: Individuals with anterior cruciate ligament reconstruction showed a knee-stabilising and pivot-shift avoidance strategy for both legs early in rehabilitation. These results may reflect an altered motor representation and motivate considerations early in rehabilitation.

Ankle Instability: Facts and Myths to Protect Your Cartilage Repairing.

The majority of patients with an osteochondral lesion of the talus (OLT) report a history of trauma. Therefore, it is important to assess for concomitant ankle instability when dealing with patients with a symptomatic OLT. The History; Alignment; Ligaments; Others "(HALO)" approach can be a helpful tool in the evaluation of patients with an OLT. If conservative treatment fails, surgery may be indicated. Although there is a lack of comparative studies investigating the effect of stabilization procedures on cartilage repair, we believe that addressing instability is a key factor in improving patient outcome.

Performance of medial pivot, posterior stabilized and rotating platform total knee arthroplasty based on anteroposterior stability and patient-reported outcome measures; a multicentre double-blinded randomized controlled trial of 210 knees.

BACKGROUND: Despite advancements in total knee arthroplasty (TKA), 10-20% of patients remain dissatisfied after surgery. Improved anteroposterior (AP) stability provided by medial pivot (MP) implants may theoretically lead to higher patient satisfaction. METHODS: AP stability and patient-reported outcome measures (PROMs) at one-year postsurgery were compared between patients who underwent TKA with MP- (n = 121), posterior stabilized (PS; n = 53) and rotating platform (RP; n = 57) implants in a double-blind multicentre randomized controlled trial (Dutch Trial Register: NL6856, 21-02-2018). AP stability was assessed at 30°, 60° and 90° of knee flexion using a KT-2000 arthrometer. PROMs were measured preoperative and one-year postsurgery. RESULTS: MP-TKA provided significant better AP stability at early flexion (30°) compared to PS- and RP-TKA (median [IQR]; 1.79 [1.14-2.77] mm vs. 3.31 [2.51-4.08] mm vs. 2.82 [1.80-4.03] mm, p < 0.001). Additionally, MP-TKA provided significant better AP stability at mid-flexion (60°) compared to PS-TKA (1.75 [1.23-2.36] mm vs. 2.14 [1.49-2.83] mm, p = 0.014). PROM improvements were comparable between implant designs. AP laxity of ≥ 4 mm at early flexion was independently of implant design associated with significantly worse Kujala scores. The incidence of ≥ 4 mm AP laxity at any knee angle was however not significantly different between implant designs. CONCLUSION: MP-, PS- and RP-TKA all provide excellent and comparable results. Although MP-TKA provided better AP stability at early flexion compared to PS- and RP-TKA, this was found to be unrelated to improved PROMs in favour of MP-TKA. More studies focusing on early and mid-flexion performance based differences between MP and other TKA designs are required to confirm our findings. Other non-implant related factors may play a more important role in the performance of TKA and are potentially worthwhile examining.

Improved Clinical Outcomes With Dynamic, Force-Controlled, Gap-Balancing in Posterior-Stabilized Total Knee Arthroplasty.

BACKGROUND: Optimal soft-tissue management in total knee arthroplasty (TKA) may reduce symptomatic instability. We hypothesized that TKA outcomes using a computer-assisted dynamic ligament balancer that acquires medial and lateral gap sizes throughout the motion arc would show improved Knee Society Scores (KSS) compared to TKAs done with a traditional tensioner at 0 and 90°. We also sought to quantify the degree to which the planned femoral rotation chosen to optimize medio-lateral balance throughout the arc of motion deviated from the femoral rotation needed to achieve a rectangular flexion gap at 90° alone. METHODS: Baseline demographics, clinical outcomes, KSSs, and femoral rotations were compared in 100 consecutive, computer-assisted TKAs done with the balancer (balancer group) to the immediately prior 100 consecutive computer-assisted TKAs done without the balancer (control group). Minimum follow-up was 13 months and all patients had osteoarthritis. Mean knee motion did not differ preoperatively (110.1 ± 13.6° balancer, 110.4 ± 12.5° control, P = .44) or postoperatively (119.1 ± 10.3° balancer, 118.8 ± 10.9° control, P = .42). Tourniquet times did not differ (93.1 ± 13.0 minutes balancer, 90.7 ± 13.0 minutes control, P = .13). Postoperative length of stay differed (40.2 ± 20.9 hours balancer, 49.0 ± 18.3 hours control, P = .0009). There were 14 readmissions (7 balancer, 7 control), 11 adverse events (4 balancer, 7 control), and 3 manipulations (1 balancer, 2 control). The cohorts were compared using Student's t-tests, Shapiro-Wilk normalities, Wilcoxon rank-sums, and multivariable logistic regression analyses. RESULTS: Postoperative KSS improvements were higher in the balancer group (P < .0001). In multivariable regression analyses, the balancer group experienced 7 ± 2 point improvement in KSS Knee scores (P < .0001) and 4 ± 2 point improvement in KSS Function scores (P = .040) compared to the control group. CONCLUSIONS: The statistically and clinically significant improvements in postoperative KSS demonstrated in the balancer cohort are likely driven by improved stability throughout the motion arc. Further study is warranted to evaluate replicability by non-design surgeons.

All-epiphyseal anterior cruciate ligament reconstruction yields superior sports performances than the trans-epiphyseal technique in skeletally immature patients: a systematic review.

BACKGROUND: Anterior cruciate ligament (ACL) tears in skeletally immature patients are increasingly common. Evidence comparing the outcomes of all-epiphyseal versus trans-epiphyseal ACL reconstruction in skeletally immature patients is limited, and the current literature could benefit from a comprehensive systematic review. The present study compared all-epiphyseal versus trans-epiphyseal ACL reconstruction in skeletally immature patients. The outcomes of interest were to compare joint laxity, patient-reported outcome measures (PROMs), return to sport, and complications. METHODS: This study was conducted according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. In November 2023, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. No additional filters were used in the database search. All the clinical studies investigating ACL reconstruction in skeletally immature patients were accessed. Only articles that clearly stated the surgical technique (all- or trans-epiphyseal) were eligible. Only articles with a minimum of 6 months of follow-up were included. Only articles that clearly stated that surgeries were conducted in children with open physis were eligible. RESULTS: Data from 1489 patients (1493 procedures) were collected, of which 32% (490 of 1489 patients) were female. The mean length of follow-up was 46.6 months. The mean age of the patients was 12.7 years. No difference was found in joint laxity (Table 3): positive pivot shift (P = 0.4), positive Lachman test (P = 0.3), and mean arthrometer laxity (P = 0.1). No difference was found in PROMs (Table 4): International Knee Documentation Committee (IKDC) (P = 0.3), Lysholm (P = 0.4), and Tegner (P = 0.7). The trans-epiphyseal technique was associated with a greater rate of patients unable to return to sports (1% versus 7%, P = 0.0001) and with a longer time to return to sports (7.7 versus 8.6 months, P = 0.01). Though the trans-epiphyseal technique was associated with a lower rate of return to sport, this difference was not statistically significant (P = 0.8). No difference was evidenced in the rate of patients who had reduced their league or level of sports activity (P = 0.6) or in the rate of patients who had returned to their previous league or level of sports activity (P = 0.7). No difference was found in the rate of complication: re-tear (P = 0.8), reoperation (P = 0.7), increased laxity (P = 0.9), and persistent instability sensation (P = 0.3). CONCLUSION: Trans-epiphyseal ACL reconstruction was associated with a greater rate of patients unable to return to sport and with a longer time to return to sport compared with the all-epiphyseal technique in skeletally immature patients. Level of evidence Level III, systematic review.

A Lateral Extra-articular Procedure Reduces the Failure Rate of Revision Anterior Cruciate Ligament Reconstruction Surgery Without Increasing Complications: A Systematic Review and Meta-analysis.

BACKGROUND: Lateral extra-articular procedures are becoming increasingly popular in association with anterior cruciate ligament (ACL) reconstruction, especially in patients with persistent rotatory instability and in a high-risk population. However, few studies have investigated the outcomes of the lateral extra-articular procedure as an associated procedure in an ACL revision (R-ACLR) setting and its benefit with respect to isolated intra-articular reconstruction. HYPOTHESIS: Lateral extra-articular procedures reduce the failure rate of revision ACL reconstruction (R-ACLR). PURPOSE: To compare subjective outcomes, knee stability, and failure and complication rates between patients who underwent ACL revision with and without an associated lateral extra-articular procedure. STUDY DESIGN: Systematic review and meta-analysis; Level of evidence, 3. METHODS: A systematic search of the PubMed, Cochrane, and OVID databases was performed on September 2022 in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Eligible studies were trials directly comparing patients who had isolated ACL revision with patients who had ACL revision associated with lateral extra-articular procedures at a minimum follow-up of 2 years. A meta-analysis was performed, and bias and the quality of the evidence were rated according to the Newcastle-Ottawa Scale. The meta-analysis was conducted according to the PRISMA guidelines. RESULTS: Eight studies were included: a total of 334 patients were treated with isolated revision (isolated (R-ACLR)) and 342 treated with combined revision and a lateral extra-articular procedure (combined (R-ACLR)). For the failure rate, the meta-analysis showed a significantly decreased relative risk reduction of 54% (P = .004) in patients with combined (R-ACLR) with respect to isolated R-ACL, whereas no difference in complication rate was observed. The combined (R-ACLR) group demonstrated a decreased risk ratio of 50% (P = .002) for having a positive pivot-shift test result and a relative risk reduction of 68% (P = .003) for having a grade 2-3 pivot shift when compared with the isolated (R-ACLR) group. Finally, no significant differences were observed among the lateral extra-articular procedures. CONCLUSION: The addition of a lateral extra-articular procedure to revision ACL significantly reduced the failure rate and postoperative pivot shift without increasing the complication rate. Anterolateral ligament reconstruction and a lateral extra-articular procedure with iliotibial band were effective in improving the outcomes of revision ACL reconstruction. Further high-level studies could help to clarify which subgroup of patients could particularly benefit from an anterolateral procedure in the context of ACL revision.

Does an early post traumatic knee brace reduce the incidence of knee rotational instability?

PURPOSE: Several anterolateral stabilization procedures have been developed recently to address rotational instability of the knee. Currently, these procedures tend to be systematically used by some practitioners. However, antero-lateral structures of the knee (including the anterolateral ligament, ALL) have a self-healing potential which can reduce the need to perform an antero-lateral procedure. In this study, it was hypothesized that early post-traumatic immobilization of the knee with a knee brace would allow partial healing of antero-lateral structures and also allow control of the pivot shift, thus avoiding antero-lateral extra-articular stabilization. The objective of this study was to compare the severity of pivot shift between two groups of patients who all experienced anterior cruciate ligament (ACL) tear and respectively underwent post-traumatic immobilization of the knee versus no immobilization. METHODS: This was a comparative, multicentric (three centers' study) retrospective, consecutive study including 168 patients who underwent ACL reconstruction between May and September 2022. The application or not of post-traumatic immobilization and its duration, the severity of pivot shift observed in the operating room under general anesthesia, the presence of anterolateral lesions as revealed by MRI and the patients' pre-injury sport activity were recorded. RESULTS: A grade 3 pivot shift was found in 44 patients (27%). It was more frequently observed in the group without a brace compared to the group with a knee brace (18 patients out of 36: 50% versus 26 patients out of 132: 19.7%; p = 0.0012). Wearing a brace, whether hinged (OR = 0.221, [0.070-0.652]; p = 0.006) or not (OR = 0.232, [0.076-0.667]; p = 0.0064), was protective from the risk of developing a significant pivot shift. CONCLUSION: This study demonstrated that the presence of pivot-shift was lower in the patients that had an early post-injury knee brace before their ACL reconstruction. Based on this result, systematic brace placement could be advocated for in patients after knee trauma. LEVEL OF EVIDENCE: III, prognostic retrospective case-control study.

Stability of novel cow-hitch suture button coracoid bone graft fixation in Latarjet procedures: a biomechanical study.

BACKGROUND: The Latarjet procedure is widely used to address anterior shoulder instability, especially in case of glenoid bone loss. Recently, cortical suture button fixation for coracoid transfer has been used to mitigate complications seen with screw placement. The aim of this biomechanical study was to evaluate the stability of a novel and cost-effective cow-hitch suture button technique, designed to be performed through a standard open deltopectoral approach, and compare this to a well-established double suture button technique. MATERIALS AND METHODS: We randomly assigned 12 fresh frozen cadaveric shoulders to undergo the Latarjet procedure with either 4 suture button (S&N EndoButton) fixations (SB group; n = 6, age 72 ± 9.8 years) or cow-hitch suture button technique using a 1.7-mm FiberTape looped sequentially in 2 suture buttons (Arthrex Pectoralis Button) placed from anterior on the posterior glenoid (CH-SB group; n = 6, age 73 ± 9.3 years). After fixation, all shoulders underwent biomechanical testing with direct loading on the graft via a material testing system. Cyclic loading was performed for 100 cycles (10-100 N) to determine axial displacement with time; each graft was then monotonically loaded to failure. RESULTS: The maximum cyclic displacement was 4.3 ± 1.6 mm for the cow-hitch suture button technique and 5.0 ± 1.7 mm for the standard double suture button technique (P = .46). Ultimate load to failure and stiffness were, respectively, 190 ± 82 N and 221 ± 124 N/mm for the CH-SB technique and 172 ± 48 N and 173 ± 34 N/mm for the standard double SB technique (P = .66 and .43). The most common failure mode was suture cut-through at the anteroinferior aspect of the glenoid for both fixation groups. CONCLUSIONS: The cow-hitch suture button technique resulted in a similar elongation, stiffness, and failure load compared to an established double suture button technique. Therefore, this cost-effective fixation may be an alternative, eligible for open approaches, to the established double suture button techniques.

Effects of textured insoles and elastic braces on dynamic stability in patients with functional ankle instability.

BACKGROUND: Functional ankle instability (FAI) is a common condition that affects individuals who have experienced previous ankle sprains. Textured insoles and elastic ankle braces have been previously used as interventions to improve stability in FAI patients. However, the optimal combination of these interventions has not been fully explored. The objective of this study was to investigate the effects of different types of textured insoles and elastic ankle braces on the dynamic stability of individuals diagnosed with FAI. METHODS: The study involved 18 FAI patients who performed single-leg landing tasks with and without wearing an eight-band elastic ankle brace while wearing textured insoles with protrusion heights of 0 mm, 1 mm, and 2 mm. The dynamic posture stability index (DPSI) and its components in the anterior-posterior (APSI), mediolateral (MLSI) and vertical (VSI) directions were calculated from the ground reaction force collected from the Kistler force plate during the first three seconds of the landing tasks. RESULTS: A significant interaction was found between textured insole type and ankle brace for DPSI (P = 0.026), APSI (P = 0.001), and VSI (P = 0.021). However, no significant interaction was observed for MLSI (P = 0.555). With elastic ankle braces, textured insoles with 1-mm protrusions significantly enhanced anterior-posterior, mediolateral, vertical, and overall stability compared to textured insoles with no and 2 mm protrusions (P < 0.05). Without elastic ankle braces, textured insoles with 1-mm protrusions significantly improved the anterior-posterior (P = 0.012) and overall stability (P = 0.014) of FAI patients compared to smooth insoles. CONCLUSIONS: The combination of textured insoles with 1-mm protrusion heights and an elastic ankle brace could enhance the dynamic stability of individuals with FAI, potentially mitigating the risk of ankle sprains.

Physiologic Motion in the Intact and Unstable Syndesmosis During Plantigrade Weightbearing in Controlled Ankle Motion Boots.

Consensus has not been reached for the optimal postoperative care after high ankle sprain and syndesmotic fixation. A potential drawback of earlier return to activity is greater instability of the ankle and fixation failure. The controlled ankle motion (CAM) boot has been an effective implementation to stabilize the leg and may aid in safe early weightbearing status. However, there is insufficient study of its effect on motion in the syndesmosis following injury. Hence, the aim of this cadaveric study was to determine the stability of the ankle with a CAM boot at 3 levels of injury: syndesmosis ligaments intact (no injury), syndesmosis ligaments cut, and syndesmosis and fibula cut. Six cadaveric legs were subjected to each level of injury and axially loaded at 1 Hz between 100 N-1.5 times body weight for 50 seconds, and axial force, axial displacement, and optical tracking data were recorded. It was found that the ankle, when protected by the CAM boot, maintained syndesmosis motion with no difference (p > .05) from the uninjured state, regardless of syndesmotic ligament and fibular injury. This finding was consistent across anterior-posterior, medial-lateral, and superior-inferior axes. Overall, our study may suggest that early weightbearing with a CAM boot maintains a physiologically range of motion in the syndesmosis.

Posterolateral stabilization of the elbow by autologous ligament reconstruction to limit long-term development of osteoarthritis.

BACKGROUND: Posterolateral instability is the most frequent form of both acute and chronic elbow instability. Joint incongruity due to posterolateral unlocking leads to shear and compression stress of the internal aspect of the humeroulnar joint. We carried out long-term analysis of patients with posterolateral elbow instability in order to determine whether, in addition to improving their symptoms, reconstruction of the lateral collateral ligament complex may play a protective role against the development of post-traumatic osteoarthritis. We hypothesized that ligament reconstruction according to the technique of O'Driscoll stabilizes the elbow and also limits the development of osteoarthritis in the long term. METHODS: Patients with symptomatic posterolateral instability of the elbow and who underwent ligament reconstruction according to the technique of O'Driscoll from January 1995 to December 2010 were identified and retrospectively included for 2 follow-up evaluations at a mean of 5 and 14 years. RESULTS: Fourteen elbows in 14 patients were included. All had a negative lateral pivot shift test and none reported a new episode of instability. Two patients (14%) had osteoarthritis. The 2 radiographic evaluations showed no progression of osteoarthritis. Osteoarthritis developed in 33% of patients with intra-articular fracture. In simple dislocations, pre-existing osteoarthritic lesions were stabilized and there were no new cases of osteoarthritis. CONCLUSION: Elbow ligament reconstruction according to the technique of O'Driscoll gives effective posterolateral stabilization and appears to protect against progression to osteoarthritic degeneration in the long term. In the absence of associated lesions, it prevents the development of osteoarthritis or the worsening of pre-existing osteoarthritis.

Remplissage reduces recurrent instability in high-risk patients with on-track Hill-Sachs lesions.

BACKGROUND: The purpose of this study was to compare recurrent instability rates between patients with on-track Hill-Sachs lesions who underwent arthroscopic labral repair (ALR) alone and those who underwent ALR with remplissage (ALR-R). Our hypothesis was that ALR-R would decrease the rate of recurrent instability, especially among patients at high risk of recurrent instability after ALR, such as contact athletes with near-track Hill-Sachs lesions. METHODS: We performed a multicenter, retrospective analysis of patients aged 14-50 years with on-track Hill-Sachs lesions who underwent ALR-R or ALR without remplissage between January 2014 and December 2019 with minimum 2-year follow-up. The exclusion criteria included prior ipsilateral shoulder surgery, >15% glenoid bone loss (GBL), off-track Hill-Sachs lesion, concomitant shoulder procedure, and connective tissue disorder. Age, sex, follow-up, and contact sports participation were recorded. GBL, Hills-Sachs interval (HSI), glenoid track, and distance to dislocation (DTD) were determined from preoperative magnetic resonance imaging scans. Affected-shoulder range of motion, Western Ontario Shoulder Instability Index scores, Subjective Shoulder Value scores, and recurrent dislocation and/or revision surgery status were also collected. A subgroup analysis was performed on "high-risk" patients (defined as participants in contact sports with DTD <10 mm) from each cohort. RESULTS: The ALR-R cohort included 56 patients, and the ALR cohort included 127. ALR-R patients had greater GBL (P = .004) and a greater HSI (P < .001). In the ALR-R cohort, only 1 patient (1.8%) had a recurrent dislocation and there were no revision operations. In comparison, in the ALR cohort, 14 patients (11.0%) had recurrent dislocations (P = .040) and 8 (6.3%) underwent revision operations (P = .11). Univariate analysis showed that remplissage protected against recurrent dislocation (P = .040) whereas younger age (P = .004), contact sports participation (P = .001), and increased GBL (P = .048) were associated with recurrent dislocation. Multivariate analysis showed that HSI (P = .001) and contact sports participation (P = .002) predicted recurrent dislocation. Among high-risk patients, only 1 patient (4.2%) in the ALR-R group had a recurrent instability event vs. 6 (66.7%) in the ALR group (P < .001). The high-risk ALR-R subgroup also had significantly better final Western Ontario Shoulder Instability Index (P = .008) and Subjective Shoulder Value (P = .001) scores than the high-risk ALR subgroup. CONCLUSIONS: Anterior shoulder instability patients with on-track Hill-Sachs lesions have lower recurrent dislocation rates after ALR plus remplissage when compared with ALR alone. This is especially true for high-risk patients, such as contact athletes with a DTD <10 mm.

Functional Interaction of the Cruciate Ligaments, Posteromedial and Posterolateral Capsule, Oblique Popliteal Ligament, and Other Structures in Preventing Abnormal Knee Hyperextension.

BACKGROUND: The ligaments and soft tissue capsular structures of the knee joint that provide a resisting force to prevent abnormal knee hyperextension have not been determined. This knowledge is required for the diagnosis and treatment of knee hyperextension abnormalities. PURPOSE: To determine the resisting moment of knee ligament and capsular structures that resist knee hyperextension. HYPOTHESIS: The combined posteromedial and posterolateral capsular structures function to provide a major restraint to prevent abnormal knee hyperextension. The anterior and posterior cruciate ligaments resist knee hyperextension but function as secondary restraints. STUDY DESIGN: Descriptive laboratory study. METHODS: A 6 degrees of freedom robotic system determined intact laxity limits in 24 cadaveric knees from 0° to 100° of knee flexion for anteroposterior limits at ±135 N, abduction-adduction limits at ±7 N·m, and external-internal limits at ±5 N·m. One loading method (n = 14 knees) used a static loading sequence with knee hyperextension to 27-N·m torque while maintaining all other degrees of freedom at zero load during sequential soft tissue cutting. The second method (n = 10 knees) used a cyclic loading sequence to decrease viscoelastic effects with soft tissue cutting at 0° of extension, followed by knee hyperextension to 27-N·m torque and cycled back to 0°. Selective soft tissue cuttings were performed of the following: oblique popliteal ligament, fabellofibular ligament, posterolateral capsule, posteromedial capsule with posterior oblique ligament, cruciate ligaments, lateral collateral ligament, popliteus, anterolateral ligament and iliotibial band, and superficial plus deep medial collateral ligaments. The sequential loss in the restraining moment with sectioning provides the function of that structure in resisting knee hyperextension. RESULTS: The median resisting force to knee hyperextension, in descending order, was the posteromedial capsule and posterior oblique ligament (21.7%), posterorolateral ligament and fabellofibular ligament (17.1%), anterior and posterior cruciate ligaments (13% and 12.9%, respectively), superior and deep medial collateral ligament (9.6%), oblique popliteal ligament (7.7%), and lateral collateral ligament (5.4%). The combined posterior capsular structures provided 54.7% and the anterior and posterior cruciate ligaments 25.3% of the total resisting moment to prevent knee hyperextension. CONCLUSION: Diagnosis of abnormal knee hyperextension involves a combination of multiple ligament and soft tissue structures without 1 primary restraint. The posteromedial and posterolateral capsular structures provided the major resisting moment to prevent knee hyperextension. The cruciate ligaments produced a lesser resisting moment to knee hyperextension. CLINICAL RELEVANCE: This is the first study to comprehensively measure all of the knee ligaments and capsular structures providing a resisting moment to abnormal knee hyperextension. These data are required for diagnostic and treatment strategies on the pathomechanics of abnormal knee hyperextension in patients after injury or developmental cases.

Accuracy of femoral tunnel positioning in medial patellofemoral ligament reconstruction: anatomic insertion leads to better clinical outcome.

PURPOSE: The medial patello-femoral ligament (MPFL) is considered the primary restraint against patellar dislocation and its reconstruction is indicated in recurrent patellar instability. An anatomical positioning of MPFL femoral insertion is recommended to achieve satisfactory clinical outcomes and prevent osteoarthritis (OA) due to an altered kinematics. The purpose of the study was first to assess the relationship between correct femoral tunnel position and better clinical outcomes and lower patellofemoral osteoarthritis rate. Second, correlation of outcomes with factors potentially affecting the results, such as the type of graft, patellar height and trochlear dysplasia. METHODS: Fifty-three patients (58 knees) who underwent MPFL reconstruction between 2009 and 2018 by a senior knee surgeon were retrospectively evaluated. Knee radiographs were performed before surgery, 12 months later and at last follow-up to assess trochlear dysplasia, patellar height and patellofemoral OA. The tibial tuberosity-trochlear groove (TT-TG) value was measured on a CT scan. The accuracy of graft positioning was evaluated on sagittal radiographs according to Schöttle et al. Subjective outcomes were collected before surgery, at 12 months and at last follow-up using several validated scores. RESULTS: Forty-six patients (51 knees) with a mean age of 24.1 ± 7.4 years were included in the study. Mean follow-up was 8.9 ± 2.1 years. A significant improvement in all clinical scores was observed at 12 months and final follow-up. Anatomic Insertion (AI) of reconstructed MPFL was considered optimal in 33 (64.7%) and sub-optimal in 18 (35.3%) patients. Sub-optimal AI resulted in lower Kujala, IKCD and higher VAS score (p < 0.01); moreover, for every 1 mm distance in any direction from the ideal insertion, a decrease of 0.8 [95% CI (-1.4; -0.2)] in Kujala score and 0.8 [95% CI (-1.3; -0.3)] in IKDC was observed. At final follow-up, 8 patients presented patellofemoral OA Iwano grade 3 (15.7%): although that incidence did not correlate to graft positioning, the use the artificial ligament in all these cases appeared to be significant. CONCLUSION: The present study confirms the importance of an optimal anatomic femoral insertion in MPFL reconstruction, reporting a significant positive correlation between graft positioning and clinical outcome. No significant correlations were found between anatomic insertion and patello-femoral OA development. LEVEL OF EVIDENCE: IV.

Lateral Collateral Ligament and Biceps Femoris Tendon Fixation with a Suture Anchor to the Tibial Metaphysis after Proximal Fibula En Bloc Resections Preserve Lateral Knee Stability.

This study aims to analyze the functional outcomes and lateral knee stability of patients who underwent lateral collateral ligament (LCL) and biceps femoris tendon reconstruction with suture anchors after proximal fibula en bloc resection for bone tumors. Patients who underwent proximal fibular en bloc resection between 2007 and 2018 were retrospectively viewed. Patients were invited to visit the clinic, and their functional scores were evaluated using the Musculoskeletal Tumor Society Scoring (MSTS) system. Lateral knee stability was evaluated by varus stress radiographs obtained at 20 degrees of flexion, and the range of motion (ROM) of the bilateral knee was assessed. Side-to-side differences were graded according to the International Knee Documentation Committee (IKDC) criteria and compared between types I and II resections. A total of 17 patients (4 males and 13 females) with a mean age of 31.1 ± 17.1 (range: 13-65) years at the time of surgery were available for radiological and clinical examination at a mean follow-up of 68.6 ± 36.4 (range: 22-124) months after surgery. In terms of ROM measurements, IKDC grades and side-to-side differences in both flexion and extension were not significantly different between the groups. On varus stress radiographs, lateral knee gapping was measured to be 0.93 ± 0.91 mm in type-I resections and 1.83 ± 0.45 mm in type-II resections, and statistically significant differences were detected among the groups (p = 0.039). When the values were graded according to IKDC criteria, none of the knees were classified as abnormal, and no difference was observed between the groups. Mean MSTS score of patients with type-I resections was significantly higher than those of patients with type-II resections (92.7 vs. 84.4%, p = 0.021). In the subscale analysis, a significant difference was observed in the support scores (type I = 94.5%, type II = 70%; p = 0.001). The reattachment of LCL and biceps femoris tendon to the tibial metaphysis with a suture anchor is a simple and effective method to prevent lateral knee instability after proximal fibula resections.

Arthroscopic centralization reduces extrusion of the medial meniscus with posterior root defect in the ACL reconstructed knee.

PURPOSE: The purpose of this study was to evaluate the effects of arthroscopic meniscal centralization reinforcement for a medial meniscus (MM) posterior root defect on knee kinematics and meniscal extrusion in the anterior cruciate ligament reconstructed (ACLR) knee. The hypothesis was that the medial meniscus centralization would reduce extrusion and anterior laxity in ACLR knee with a medical meniscal defect. METHODS: Fourteen fresh-frozen human cadaveric knees were tested using a six-degrees-of-freedom robotic system under the following loading conditions: (a) an 89.0 N anterior tibial load, (b) 5.0 Nm internal and external rotational torques, (c) a 10.0 Nm valgus and varus loadings, and (d) a combined 7.0 Nm valgus moment and then a 5.0 Nm internal rotation torque as a static simulated pivot shift. The tested knee states included: (1) anatomic single-bundle cruciate ligament reconstruction with intact medial meniscus (MM Intact), (2) anatomic single-bundle cruciate ligament reconstruction with medial meniscus posterior root defect (MM Defect), (3) Anatomic single-bundle cruciate ligament reconstruction with medial meniscus arthroscopic centralization (MM Centralization). Medial meniscus arthroscopic centralization was performed using 1.4 mm anchors with #2 suture. The MM extrusion (MME) was measured using ultrasound under unloaded and varus loading conditions at 0° and 30° of flexion. RESULTS: Anterior tibial translation (ATT) increased significantly with MM posterior root defect compared to MM intact at all flexion angles. With MM centralization, ATT was not significantly different from the intact meniscus at 15° and 30° of flexion. Meniscus extrusion increased significantly with the root defect compared to intact meniscus and decreased significantly with meniscal centralization compared to the root defect at both flexion angles. CONCLUSIONS: In ACL reconstruction, cases involving irreparable medial meniscal posterior root tears, applying arthroscopic centralization for avoiding the meniscal extrusion should be considered. Clinically, in ACL reconstruction cases with irreparable medial meniscal posterior root tears, applying arthroscopic meniscal centralization for avoiding the meniscal extrusion should be considered. Meniscal centralization decreases the extrusion of the MM and offers improvements in knee laxity.