Treatment of avulsion fracture of posterior cruciate ligament tibial insertion by minimally invasive approach in posterior medial knee

Objective

The study aims to explore the feasibility and clinical effect of posterior minimally invasive treatment of cruciate ligament tibial avulsion fracture.

Methods

Posterior knee minimally invasive approach was used to treat avulsion fracture of posterior cruciate ligament (PCL) tibia in 15 males and 11 females. The length of the incision, intraoperative blood loss, operation time, postoperative hospital stay, residual relaxation, and fracture healing time were analyzed to evaluate the curative effect, learning curve, and advantages of the new technology. Neurovascular complications were recorded. During the postoperative follow-up, the International Knee Joint Documentation Committee (IKDC), Lysholm knee joint score, and knee joint range of motion were recorded to evaluate the function.

Results

All 26 patients were followed up for 18-24 months, with an average of 24.42 ± 5.00 months. The incision length was 3-6 cm, with an average of 4.04 ± 0.82 cm. The intraoperative blood loss was about 45-60 ml, with an average of 48.85 ± 5.88 ml. The operation time was 39-64 min, with an average of 52.46 ± 7.64 min. The postoperative hospital stay was 2-5 days, with an average of 2.73 ± 0.87 days. All incisions healed grade I without neurovascular injury. All fractures healed well with an average healing time of 9.46 ± 1.33 weeks (range, 8-12 weeks). The Lysholm score of the affected knee was 89-98 (mean, 94.12 ± 2.49) at 12-month follow-up. The IKDC score was 87-95 with an average of 91.85 ± 2.19, and the knee range of motion was 129-148° with an average of 137.08 ± 5.59°. The residual relaxation was 1-3 mm, with an average of 1.46 ± 0.65 mm.

Conclusion

This minimally invasive method provides sufficient exposure for internal fixation of PCL tibial avulsion fractures without the surgical complications associated with traditional open surgical methods. The process is safe, less invasive, and does not require a long learning curve.

Biomechanical comparison of proximal, distal, and anatomic tibial tunnel for transtibial posterior cruciate ligament reconstruction

No consensus has been reached on the optimal position of PCL tibial tunnel. The purpose of this study was to compare the biomechanical properties of proximal, distal and anatomic tibial tunnel in transtibial posterior cruciate ligament reconstruction. An in-vitro model of transtibial posterior cruciate ligament reconstruction was simulated using porcine tibias and bovine extensor tendons. Two models of biomechanical testing, load-to-failure loading, and cyclic loading, were performed in this study. The load-to-failure loading found that distal tibial tunnel resulted in greater ultimate load and yield load than the anatomic and proximal tunnel group (p < 0.05), whereas there were no significant differences in mean tensile stiffness among three groups (p > 0.05). The cyclic loading found no differences in the graft displacement at 250, 500, and 1000 cycles among three groups (p > 0.05). It was found that distal tibial tunnel showed superior ultimate load and yield load in load-to-failure loading testing compared with proximal and anatomic tibial tunnels, whereas no significant difference was found in terms of the mean displacement of the survived grafts in cyclic loading testing among three groups.

A Sleepwalking Patient Presenting with Concomitant ACL, PCL, and Meniscal Root Avulsion Fractures: A Case Report

Introduction

Tibial-sided anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) avulsion fractures compose a rare subset of cruciate ligament injuries. Fixation strategies are mixed in the literature, particularly regarding the PCL, which has traditionally been addressed using an open approach.

Case Report

A 41-year-old male sustained avulsion fractures of the tibial eminence involving the ACL, PCL, and posterior medial meniscal root through an unknown mechanism while sleepwalking. Surgical treatment comprised of entirely arthroscopic reduction and transtibial suture fixation. Only seven cases of combined ACL/PCL avulsion fracture have been reported and all but one utilized open fixation for at least the PCL and restricted weight-bearing postoperatively.

Conclusion

This previously unreported triad of injury was successfully managed arthroscopically, negating a posterior approach to the knee. Early post-operative weight-bearing and aggressive range of motion aided in swift recovery and a favorable outcome.

Morphological Risk Factors for Posterior Cruciate Ligament Tear and Tibial Avulsion Injuries of the Tibial Plateau and Femoral Condyle

BACKGROUND

Identification of morphological risk factors associated with the knee that threaten ligaments is important for understanding injury mechanisms and prevention. However, the morphological risk factors for posterior cruciate ligament (PCL) lesions are not clearly understood.

PURPOSE

To investigate whether the medial tibial depth (MTD), medial and lateral posterior tibial slope, asymmetry of the medial and lateral slopes, radius of the sagittal plane medial femoral condyle, coronal tibial slope, and notch width index (NWI) were risk factors for PCL intrasubstance tearing (PCLIT) and tibial avulsion fractures (PCLAF).

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Between January 2015 and March 2022, 82 patients with isolated PCLIT, 68 patients with isolated PCLAF, and 82 controls without any ligamentous or meniscal pathologic findings as determined via physical examination and magnetic resonance imaging were included. Values were compared among the 3 groups. Logistic regression analysis was performed to confirm the risk factors. Receiver operating characteristic curves were defined for the morphological indicators and combination of risk factors.

RESULTS

Logistic regression analysis revealed (1) MTD, lateral minus medial posterior tibial slope, radius of the posterior circle of the medial femoral condyle, and NWI as significant independent predictors for PCLIT and (2) MTD and NWI for PCLAF. The areas under the curve combining the 4 indicators for PCLIT and noncontact PCLIT were 0.79 (95% CI, 0.72-0.86) and 0.90 (95% CI, 0.85-0.96), respectively. The area under the curve for the combination of MTD and NWI for PCLAF was 0.78 (95% CI, 0.70-0.86).

CONCLUSION

Decreased MTD and NWI were associated with an increased incidence of PCLIT and PCLAF. Increased asymmetry of the medial and lateral slopes and the radius of the posterior circle of the medial femoral condyle were associated with the presence of PCLIT. In addition, the model of a combination of risk factors showed good predictive ability for noncontact PCLIT. These findings may aid clinicians in identifying patients at risk for PCL lesions. Further studies are warranted for identifying the effect of these factors on biomechanical mechanisms.

Comparison of Posterior Cruciate Ligament Reconstruction Using an All-Inside Technique With and Without Independent Suture Tape Reinforcement

Background

Biomechanical studies support the use of suture tape reinforcement for limiting graft elongation and increasing strength in knee ligament reconstructions.

Purpose

To compare posterior cruciate ligament (PCL) laxity, complication and reoperation rates, and patient-reported outcomes (PROs) after all-inside single-bundle PCL reconstruction (PCLR) with versus without independent suture tape reinforcement.

Study Design

Cohort study; Level of evidence, 3.

Methods

A retrospective cohort study of consecutive patients who underwent primary, all-inside allograft single-bundle PCLR with and without independent suture tape reinforcement at a single academic institution from 2012 to 2019. Medical records were reviewed for patient characteristics, additional injuries, and concomitant procedures. PRO scores (including the International Knee Documentation Committee [IKDC], Tegner activity scale, and Lysholm scores), bilateral comparison kneeling radiographs, and physical examination findings were collected at a minimum of 2 years postoperatively.

Results

Included were 50 patients: 19 with suture tape reinforcement (mean age 30.6 ± 2.9 years) and 31 without suture tape reinforcement (control group; mean age 26.2 ± 1.6 years). One PCLR graft in the suture tape group failed. Posterior drawer examination revealed grade 1+ laxity in 4 of 19 (21%) of the suture tape cohort versus 6 of 31 (19%) of the control cohort (P > .999). Bilateral kneeling radiographs showed similar side-to-side differences in laxity between the groups (suture tape vs control: mean, 1.9 ± 0.4 vs 2.6 ± 0.6 mm; P = .361). There were no statistically significant differences between the groups in postoperative IKDC (suture tape vs control: 79.3 vs 79.6; P = .779), Lysholm (87.5 vs 84.3; P = .828), or Tegner activity (5.6 vs 5.7; P = .562) scores.

Conclusion

All-inside single-bundle PCLR with and without independent suture tape reinforcement demonstrated low rates of graft failure, complications, and reoperations, with satisfactory PROs at a minimum 2-year follow-up. Radiographic posterior tibial translation was comparable between the 2 groups.

Application of CT-MRI Fusion-Based Three-Dimensional Reconstruction Technique in the Anatomic Study of Posterior Cruciate Ligament

Objective

During PCL reconstruction surgery, precise and personalized positioning of the graft tunnel is very important. In order to obtain patient‐specific anatomical data, we established a three‐dimensional knee joint fusion model to provide a unified imaging strategy, as well as anatomical information, for individualized and accurate posterior cruciate ligament (PCL) reconstruction.

Methods

This is an exploration study. From January 2019 to January 2020, 20 healthy adults randomly were enrolled and assessed via CT and MRI imaging. A three‐dimensional fusion model of the knee joint was generated using the modified MIMIMICS and image fusion software. On the fused image, the areas of the femoral and tibial PCL footprint of both knees were measured. The anatomical center of the PCL footprint was measured at the femoral and tibial ends. The relevant bony landmarks surrounding the PCL femoral and tibial attachment were also measured. Paired t‐tests were employed for all statistical analyzes, and p < 0.05 was considered as statistically significant.

Results

All 20 subjects achieved successful image fusion modeling and measurement, with an average duration of 12 h. The lengths of the LF1‐LF3 were 32.1 ± 1.8, 6.8 ± 2.5, and 23.3 ± 2.1 mm, respectively. The lengths of the LT1‐LT3 were 37.3 ± 3.3, 45.6 ± 5.3, and 6.0 ± 1.2 mm, respectively. The distances between the tibial PCL center of the left knee to the medial groove, champagne‐glass drop‐off, and the apex of the medial intercondylar were 8.4 ± 2.4, 9.2 ± 1.8, and 15.3 ± 1.4 mm, respectively, and the corresponding distances from the right knee were 8.0 ± 2.0, 9.4 ± 2.2, and 16.1 ± 1.8 mm, respectively. We observed no difference between the bilateral sides, in terms of the distance from the PCL center to the PCL attachment‐related landmark, under arthroscopic guidance. The area of the femoral and tibial PCL footprints on the left knee were 115.3 ± 33.5 and 146.6 ± 24.4 mm², respectively, and the corresponding areas on the right knee were 121.8 ± 35.6 and 142.8 ± 19.5 mm², respectively. There was no difference between the bilateral sides in terms of the PCL footprint areas.

Conclusion

In the fusion image, the PCL attachment center and relevant bony landmarks which can be easily identified under arthroscopy can be accurately measured. The model can also obtain personalized anatomical data of the PCL on the unaffected side of the patient, which can guide clinical PCL reconstruction.

Differentiation in Posterior Tibial Slope by Sex, Age, and Race: A Cadaveric Study Utilizing 3-Dimensional Computerized Tomography

BACKGROUND

Posterior tibial slope (PTS) has recently gained increased attention for its possible role in anterior cruciate ligament and posterior cruciate ligament injury. The possible differences among age, sex, and ethnicity in PTS have not yet been reported.

PURPOSE

To describe demographic variances of proximal tibial anatomy and to detect differences in regard to ethnicity, sex, and age.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

In total, 250 cadaveric specimens with full-body computerized tomography scans from the New Mexico Descendant Imaging Database were randomly selected (inclusion/exclusion criteria: older than 18 years, complete imaging of the knee without previous surgery or arthroplasty) and reviewed by 3 independent observers measuring medial posterior tibial slope (MPTS), lateral posterior tibial slope (LPTS), and global posterior tibial slope (PTS), which was calculated as the mean of the MPTS and LPTS. Individuals were evenly divided among male and female and ethnicities/races: African American/Black, Asian American, Hispanic, Native American, and White. Intraclass correlation coefficient was calculated for interobserver reliability and analysis of variance statistical testing to determine statistical significance between groups. Fisher exact test was also used to understand PTS differences among ethnicities when looking at clinically significant values for potential ligamentous injury.

RESULTS

Measurements were obtained from 250 specimens with a mean age of 49.4 years (range, 19 to 103 years). The mean PTS was 8.92° (range, -9.4° to 14.95°). Asian Americans had a 1.7° greater mean MPTS than Whites (P = .016), and African Americans/Blacks had a 1.6° greater mean PTS than Whites (P = .022). No difference in mean PTS was seen between age and sex. When looking at clinically significant PTS, 61 (24.4%) individuals had tibial slopes <6° or >12°, 32 (12.8%) and 29 (11.6%), respectively. Statistically significant differences were seen among ethnicities with PTS <6° (P = .017) but not with PTS >12° (P = .106). No sex-based differences were seen in the percentage of specimens with a PTS of >12° or <6°.

CONCLUSION

Among ethnicities, African Americans/Blacks and Asian Americans have increased PTS in comparison with Whites. Nearly 25% of individuals have clinically significant slopes of <6° or >12°, with no difference in tibial slope among sex or age groups.

Midterm Outcomes After Revision Posterior Cruciate Ligament Reconstruction With a Single-Bundle Transtibial Autograft

Background:

There is a lack of consensus regarding the optimal technique for revision posterior cruciate ligament (PCL) reconstruction.

Purpose:

To evaluate midterm outcomes after revision PCL reconstruction using a single-bundle transtibial autograft.

Study Design:

Case series; Level of evidence, 4.

Methods:

We reviewed 17 patients who underwent revision PCL reconstruction performed in our medical center by a single surgeon from 2003 to 2016. The cohort included 12 male and 5 female patients with a mean age of 31.3 years (range, 17-48 years). All of the patients underwent single-bundle transtibial reconstruction using the same surgical technique and were reviewed at a minimum of 4 years postoperatively. Preoperative and postoperative posterior stress radiography was performed. The preoperative tibial slope and tibiofemoral angle were also measured. Preoperative and postoperative functional outcomes were evaluated using the International Knee Documentation Committee (IKDC) subjective and objective scores as well as the Lysholm score.

Results:

The most common factor that contributed to the failure of primary surgery was misplaced tunnels, especially on the femoral side. There were 2 patients who had grade 2 laxity preoperatively, and 15 patients had grade 3 laxity preoperatively. At the latest follow-up, all 17 patients had grade 1 laxity. On posterior stress radiography, posterior displacement improved from 10.8 ± 2.1 mm preoperatively to 2.9 ± 1.1 mm at the latest follow-up (P < .001). The IKDC subjective score improved from 34.9 ± 6.8 preoperatively to 75.3 ± 15.7 postoperatively (P < .001), and the Lysholm score improved from 38.1 ± 10.0 preoperatively to 88.5 ± 7.6 postoperatively (P < .001). All patients reached the minimal clinically important difference (MCID) for the Lysholm score, and 94% reached the MCID for the IKDC subjective score, with 65% reaching the Patient Acceptable Symptom State.

Conclusion:

According to the findings of this study, arthroscopic revision PCL reconstruction with a single-bundle transtibial autograft offered satisfactory outcomes at midterm follow-up.

Hamstring, bone-patellar tendon-bone, quadriceps and peroneus longus tendon autografts for primary isolated posterior cruciate ligament reconstruction: a systematic review

INTRODUCTION

Several autografts are available to reconstruct the posterior cruciate ligament (PCL).

SOURCE OF DATA

Current scientific literature published in PubMed, Google scholar, Embase and Scopus.

AREAS OF AGREEMENT

Hamstring, bone-patellar tendon-bone (BPTB), quadriceps and peroneus longus (PLT) are the most common tendon autografts used for primary isolated PCL reconstruction.

AREAS OF CONTROVERSY

The optimal tendon source for PCL reconstruction remains nevertheless debated. Identifying the most suitable tendon autograft could assist the surgeon during primary PCL reconstruction.

GROWING POINTS

The present study compared the outcome of PCL reconstruction using hamstring, BPTB, quadriceps and PLT autografts. The focus was on patient-reported outcome measures (PROMs), joint laxity, range of motion and complications.

AREAS TIMELY FOR DEVELOPING RESEARCH

All autografts are viable options for PCL reconstruction, with BTB and hamstring autografts demonstrating superior PROMs. However, further clinical investigations are required to determine the ideal autograft construct.

Exploring Anatomo-Morphometric Characteristics of Infrapatellar, Suprapatellar Fat Pad, and Knee Ligaments in Osteoarthritis Compared to Post-Traumatic Lesions

Several studies have investigated cartilage degeneration and inflammatory subchondral bone and synovial membrane changes using magnetic resonance (MR) in osteoarthritis (OA) patients. Conversely, there is a paucity of data exploring the role of knee ligaments, infrapatellar fat pad (IFP), and suprapatellar fat pad (SFP) in knee OA compared to post-traumatic cohorts of patients. Therefore, the aim of this study was to analyze the volumetric and morphometric characteristics of the following joint tissues: IFP (volume, surface, depth, femoral and tibial arch lengths), SFP (volume, surface, oblique, antero−posterior, and cranio−caudal lengths), anterior (ACL) and posterior cruciate ligament (PCL) (volume, surface, and length), and patellar ligament (PL) (volume, surface, arc, depth, and length). Eighty-nine MR images were collected in the following three groups: (a) 32 patients with meniscal tears, (b) 29 patients with ACL rupture (ACLR), and (c) 28 patients affected by end-stage OA. Volume, surface, and length of both ACL and PCL were determined in groups a and c. A statistical decrease of IFP volume, surface, depth, femoral and tibial arch lengths was found in end-stage OA compared to patients with meniscal tear (p = 0.002, p = 0.008, p < 0.0001, p = 0.028 and p < 0.001, respectively) and patients with ACLR (p < 0.0001, p < 0.0001, p = 0.008 and p = 0.011, respectively). An increment of volume and surface SFP was observed in group b compared to both groups a and c, while no differences were found in oblique, antero−posterior, and cranio−caudal lengths of SFP among the groups. No statistical differences were highlighted comparing volume, surface, arc, and length of PL between the groups, while PL depth was observed to be decreased in end-OA patients compared with meniscal tear patients (p = 0.023). No statistical differences were observed comparing ACL and PCL lengths between patients undergoing meniscectomy and TKR. Our study confirms that IFP MR morphometric characteristics are different between controls and OA, supporting an important role of IFP in OA pathology and progression in accordance with previously published studies. In addition, PL depth changes seem to be associated with OA pathology. Multivariate analysis confirmed that OA patients had a smaller IFP compared to patients with meniscal tears, confirming its involvement in OA.

The Effect of Posterior Cruciate Ligament Release on Kinematics and Outcomes in Primary Total Knee Arthroplasty With a Dual-Pivot Conforming Polyethylene

BACKGROUND

Ultracongruent bearings are increasingly utilized in total knee arthroplasty (TKA); however, implications of surgical technique on knee kinematics and outcomes with these bearings are not well understood. This study's purpose was to evaluate the relationship of 3-dimensional knee kinematics and patient-reported outcome measures (PROMs) in a dual-pivot congruent bearing TKA with and without posterior cruciate ligament (PCL) release.

METHODS

Forty patients undergoing TKA with an asymmetric ultracongruent bearing were prospectively enrolled for gait analysis preoperatively and 4 months postoperatively. Three-dimensional gait analysis was performed utilizing infrared motion capture. Knee kinematic data and PCL disposition were analyzed for correlations with PROMs.

RESULTS

The PCL was fully released in 52.5% (21/40) of cases. Greater maximum anteroposterior femoral translation correlated with lower Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (rho = -0.596, P = .012), greater Knee Society Score pain with level walking (rho = 0.411, P = .101), and greater Knee Society Score pain while climbing stairs (rho = 0.469, P = .058) at 4-month follow-up. The PCL-release group was associated with greater maximum femoral anteroposterior translation (9.8 vs 5.5 mm, P = .053) and greater maximum internal tibial rotation (-6.2° vs -3.0°, P = .040), supporting a more anterior-based position of the medial condyle. The PCL released group had lower median Knee Injury and Osteoarthritis Outcome Score for Joint Replacement scores (70.7 vs 76.3, P = .031) and reported that their knees "sometimes or always" feel normal less frequently (81.8% vs 92.3%, P = .576).

CONCLUSION

With this asymmetric ultracongruent bearing TKA, preservation or partial titration release of the PCL, as opposed to full PCL release, appears to minimize deleterious anterior femoral translation and internal tibial rotation, which is correlated with optimized patient-reported outcomes.

LEVEL OF EVIDENCE

II.

Increased Prevalence of Posterior Cruciate Ligament Dysfunction Noted With 3-Dimensional Intraoperative Kinematic Evaluation in Total Knee Arthroplasty

BACKGROUND

Poor restoration of cruciate-driven kinematics after total knee arthroplasty may result from technical difficulties, but the ligament may also be functionally compromised by the presence of arthritis. We asked whether the function of the posterior cruciate ligament (PCL) could be assessed intraoperatively to predict the quality of the resulting posterior cruciate kinematics.

METHODS

PCL integrity was assessed using intraoperative infrared trackers to monitor knee kinematics in 73 patients. Three-dimensional images of the femur and tibia were projected onto a screen, allowing the surgeon to visualize kinematic relationships in real time. We measured femoral rollback (distance of femoral contact as a percentage of antero-posterior tray width) from images captured by the robotic system during initial kinematic assessment, gap balancing, and assessment of the final construct and from lateral flexion radiographs obtained 2 years after surgery. Associations were characterized using Pearson's correlation and graphical methods.

RESULTS

Thirty-six knees (49%) showed rollback <60% during gap balancing, indicative of PCL insufficiency. The rollback during gap balancing was positively correlated with that seen in the final cruciate retaining constructs (r = 0.60, P < .001), which in turn predicted rollback 2 years after surgery on lateral flexion X-rays (r = 0.50, P = .006).

CONCLUSION

Intraoperative functional evaluations can allow the surgeon to identify cases where rollback is not consistent with desirable knee kinematics, and posterior stabilization may lead to a better outcome for those patients.

Association between magnetic resonance imaging characteristics and pathological findings in entire posterior cruciate ligament with mucoid degeneration

Magnetic resonance imaging (MRI) findings of a tram-track appearance and celery stalk appearance in mucoid degeneration of the cruciate ligament are valuable; however, their pathological basis is unclear. Because these appearances are generally seen throughout the entire ligament, the association between MRI findings and pathological findings must be verified in specimens of the whole degenerated ligament, including the ligamentous attachments to bone. We herein report two cases of mucoid degeneration of the posterior cruciate ligament with osteoarthritis of the knee requiring total knee arthroplasty. The entire degenerated ligament, including the ligamentous attachments to bone, was removed and pathologically evaluated. On pathological examination, the central portion of the lesion showed typical mucoid degeneration, whereas the marginal and adherent portions showed normal ligament tissue, consistent with a tram-track appearance on T2-weighted MRI. The fibrous normal ligament tissues in the longitudinal direction in regions of mucoid degeneration were consistent with a celery stalk appearance on T2-weighted MRI. No mucoid degeneration was found in the attachment area. The tram-track appearance and celery stalk appearance of mucoid degeneration on MRI can be explained by the pathological findings.

Stress Radiographs in the Posterior Drawer Position at 90° Flexion Should Be Used for the Evaluation of the PCL in CR TKA with Flexion Instability

The purpose of this study was to define a cut-off value for the posterior drawer position in stress radiography that confirms an insufficiency of the posterior cruciate ligament (PCL) in cruciate-retaining (CR) total knee arthroplasty (TKA). In this retrospective study, 20 symptomatic patients with flexion instability and suspected PCL insufficiency in CR TKA were included. Asymptomatic patients served as an age- and sex-matched control group. All of the patients had undergone stress radiography, and the posterior translation was measured in a posterior drawer position at 30° and 90° flexion. The two groups were compared using t-tests and chi-square tests. The stress radiographs showed significantly more posterior translation in the symptomatic group (p < 0.01). Stress radiographs at 90° flexion more effectively discriminated between the patients with and without PCL insufficiency compared with those carried out at 30° flexion. Sensitivity and specificity testing revealed the best sensitivity (90.5%) and the best specificity (94.7%) at 90° posterior drawer radiographs at a cut-off value of 10 mm. Stress radiographs including the posterior drawer position at 90° flexion should be part of the diagnostic algorithm in patients with suspected flexion instability. A posterior translation of more than 10 mm in CR TKA strongly indicates an insufficiency of the PCL.

[Short-term effectiveness of one-stage anterior and posterior cruciate ligaments and posterolateral complex reconstruction combined with medial collateral ligament repair for KD- knee dislocation]

OBJECTIVE

To investigate the short-term effectiveness of one-stage anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and posterolateral complex (PLC) reconstruction combined with medial collateral ligament repair for KD-Ⅳ knee dislocation.

METHODS

Between January 2018 and June 2020, 9 patients with KD-Ⅳ knee dislocation were treated. Of 9 cases, 7 were male and 2 were female with an average age of 32.3 years (range, 23-43 years). The knee dislocation was caused by falling from height in 6 cases and traffic accident in 3 cases. The injury located at left knee in 2 cases and right knee in 7 cases. The time from injury to operation was 14-24 days, with an average of 19 days. The preoperative International Knee Joint Documentation Committee (IKDC) score was 45.6±4.2, Lysholm score was 42.4±7.0, and the knee joint active flexion range of motion was (75.2±12.3)°. The posterior drawer test, pivot-shift test, Dial test, and 0° valgus stress test were all positive. Under arthroscopy, PCL was reconstructed with the autologous tendons, ACL with allogeneic Achilles tendon, PLC with the allogeneic anterior tibial tendon by Larson enhanced reconstruction method, and MCL was repaired with anchor or simple suture.

RESULTS

The operation time was 2-3 hours (mean, 2.5 hours). All incisions healed by first intention after operation. All patients were followed up12-25 months (mean, 16.1 months). After operation, 2 cases developed knee flexion disorder and pain, and 1 case had knee joint stiffness. At last follow-up, the IKDC score was 76.9±7.4, the Lysholm score was 81.6±6.4, and the knee active flexion range of motion was (122.9±7.2)°, all of which significantly improved when compared with preoperative ones ( P<0.05). During follow-up, there was no failure of the grafts. At last follow-up, there were significant differences in the posterior drawer test, pivot-shift test, Dial test, and 0° valgus stress test between pre- and post-operation ( P<0.05). The imaging review showed that the positions of the bone tunnels were satisfactory, the reconstructed ACL, PCL, and PLC structures were continuous, and MCL insertions were restored.

CONCLUSION

One-stage ACL, PCL, and PLC reconstruction combined with MCL repair to treat KD-Ⅳ knee dislocation can effectively restore knee joint stability, improve joint laxity, and improve joint movement.

[Experience in diagnosis and treatment of KD- M dislocation of knee joint]

OBJECTIVE

To explore the effectiveness of one-stage posterior medial corner (PMC) repair or reconstruction combined with anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction in treating KD-ⅢM dislocation.

METHODS

The clinical data of 15 patients with knee KD-ⅢM dislocation who met the selection criteria between January 2016 and July 2019 were retrospectively analyzed. There were 9 males and 6 females, aged 22-61 years (mean, 40.3 years). Injuries were caused by violence of flexion, valgus, and external rotation, including 10 cases of traffic accident injuries, 3 cases of crush injuries, 1 case of winch injury, and 1 case of explosion injury. The time from injury to operation ranged from 3 days to 6 months, with an average of 18.5 days. PMC repair combined with PCL+ACL reconstruction was performed in 10 cases in acute stage (within 3 weeks after injury), including 3 cases of irreducible dislocation. PMC+PCL+ACL reconstruction was performed in 5 cases with chronic dislocation. Before operation and at last follow-up, the knee joint function was evaluated by Lysholm score and International Knee Documentation Committee (IKDC) 2000 score. KT-3000 was used to evaluate the forward stability of the knee (calculated the difference of tibial anterior displacement of both knees), the X-ray films of the stress position of the knee joint was used to evaluate the valgus of the knee (calculated the difference of medial joint space width of both knees) and the backward stability (calculated the difference of tibial posterior displacement of both knees), and the internal and external rotation stability was evaluated by knee flexion 30° tibial external rotation and knee flexion 90° tibial internal rotation tests (calculated the difference of tibial internal rotation and the difference of tibial external rotation of both knees).

RESULTS

The operation time was 120-240 minutes, with an average of 186.5 minutes. Patients were followed up 24-48 months, with an average of 27.4 months. There was no complication such as infection, deep vein thrombosis, vascular injury, or heterotopic ossification. At last follow-up, the Lysholm score, IKDC2000 score, the difference of tibial anterior displacement of both knees, the difference of medial joint space width of both knees, the difference of tibial posterior displacement of both knees, the difference of tibial internal rotation and the difference of tibial external rotation of both knees significantly improved when compared with preoperative ones ( P<0.05). According to the IKDC2000 valgus stability grading standard, there were 3 cases of grade C and 12 cases of grade D before operation, and 10 cases of grade A and 5 cases of grade B at last follow-up, which was significantly improved when compared with that before operation ( Z=-4.930, P=0.000). At last follow-up, the pivot shift tests of 15 patients were negative. The anterior and posterior drawer tests of 10 patients were negative, 5 patients had mild instability, both the anterior and posterior drawer tests were positive.

CONCLUSION

KD-ⅢM dislocation of the knee joint can lead to the posterior medial and anterior instability. Acute dislocation combined with "dimple sign" requires surgical reduction as soon as possible to repair PMC and reconstruct PCL and ACL. In chronic patients, PMC is difficult to repair, it is recommended to reconstruct PMC, PCL, and ACL at one stage to improve knee joint stability. The early and middle effectiveness are satisfactory.

Ligament mechanics of ageing and osteoarthritic human knees

Knee joint ligaments provide stability to the joint by preventing excessive movement. There has been no systematic effort to study the effect of OA and ageing on the mechanical properties of the four major human knee ligaments. This study aims to collate data on the material properties of the anterior (ACL) and posterior (PCL) cruciate ligaments, medial (MCL) and lateral (LCL) collateral ligaments. Bone-ligament-bone specimens from twelve cadaveric human knee joints were extracted for this study. The cadaveric knee joints were previously collected to study ageing and OA on bone and cartilage material properties; therefore, combining our previous bone and cartilage data with the new ligament data from this study will facilitate subject-specific whole-joint modelling studies. The bone-ligament-bone specimens were tested under tensile loading to failure, determining material parameters including yield and ultimate (failure) stress and strain, secant modulus, tangent modulus, and stiffness. There were significant negative correlations between age and ACL yield stress (p = 0.03), ACL failure stress (p = 0.02), PCL secant (p = 0.02) and tangent (p = 0.02) modulus, and LCL stiffness (p = 0.046). Significant negative correlations were also found between OA grades and ACL yield stress (p = 0.02) and strain (p = 0.03), and LCL failure stress (p = 0.048). However, changes in age or OA grade did not show a statistically significant correlation with the MCL tensile parameters. Due to the small sample size, the combined effect of age and the presence of OA could not be statistically derived. This research is the first to report tensile properties of the four major human knee ligaments from a diverse demographic. When combined with our previous findings on bone and cartilage for the same twelve knee cadavers, the current ligament study supports the conceptualisation of OA as a whole-joint disease that impairs the integrity of many peri-articular tissues within the knee. The subject-specific data pool consisting of the material properties of the four major knee ligaments, subchondral and trabecular bones and articular cartilage will advance knee joint finite element models.

The 50 Top-Cited Articles on the Posterior Cruciate Ligament: A Bibliometric Analysis and Review

Background:

Limited attention has been paid to the natural history, management, and treatment outcomes related to the posterior cruciate ligament (PCL)–deficient knee joint.

Purpose:

To perform a comprehensive bibliometric analysis to evaluate the 50 top-cited articles in PCL research.

Study Design:

Cross-sectional study.

Methods:

We performed a keyword-based search in the Thomson Reuters Web of Science to generate a list of the 50 most cited articles relevant to the PCL. The included articles were analyzed according to journal, country of origin, publication year, total number of citations, citations per year, citation trends, and type of study (clinical vs basic science).

Results:

The 50 top-cited articles were published between 1975 and 2012, and the number of individual article citations ranged between 98 and 410. The listed articles were published in 7 journals, with the American Journal of Sports Medicine contributing to more than half of the articles and citations. The United States contributed the most articles (84%) and citations (n = 4873). There were 32 clinical studies and 18 basic science studies. All clinical studies had level 4 clinical evidence, and topics included the natural history of PCL tears, factors predicting the need for surgical intervention, and long-term outcomes of isolated PCL injuries and combined capsuloligamentous injuries. Most (77.8%) of the top-cited basic science articles consisted of experimental or biomechanical studies on human cadaveric knees.

Conclusion:

The current analysis suggests that PCL research is still evolving and needs high-quality prospective evidence to establish sound recommendations.

Twelve Weeks of a Staged Balance and Strength Training Program Improves Muscle Strength, Proprioception, and Clinical Function in Patients with Isolated Posterior Cruciate Ligament Injuries

Ligament reconstruction is indicated in patients with an isolated posterior cruciate ligament (PCL) injury who fail conservative treatment. To eliminate the need for PCL reconstruction, an ideal rehabilitation program is important for patients with an isolated PCL injury. The purpose of this study was to investigate the improvement in functional outcome, proprioception, and muscle strength after a Both Sides Up (BOSU) ball was used in a balance combined with strength training program in patients with an isolated PCL injury. Ten patients with isolated PCL injuries were recruited to receive a 12 week training program as a study group. In the control group (post-PCL reconstruction group), ten subjects who had undergone isolated PCL reconstruction for more than 2 years were enrolled without current rehabilitation. The Lysholm score, IKDC score, proprioception (active and passive), and isokinetic muscle strength tests at 60°/s, 120°/s, and 240°/s, were used before and after training on the injured and normal knees in the study group, and in the post-PCL reconstruction group. The results were analyzed with a paired t-test to compare the change between pre-training, post-training, and the normal leg in the study group, and with an independent t-test for comparisons between the study and post-PCL reconstruction groups. Both the Lysholm and IKDC scores were significantly improved (p < 0.01) after training, and no difference was observed compared to the post-PCL reconstruction group. The active and passive proprioception was improved post-training compared to pre-training, with no difference to that in the post-PCL reconstruction group. Isokinetic knee quadriceps muscle strength was significantly greater post-training than pre-training in PCL injured knees at 60°/s, 120°/s, and 240°/s, and in hamstring muscle strength at 60°/s and 120°/s. Muscle strength in the post-training injured knee group showed no significant difference compared to that in the post-training normal leg and the post-PCL reconstruction group. The post-training improvement of muscle strength was higher in the PCL injured leg compared to the normal leg and there was no difference between the dominant and non-dominant injured leg in the study group. After 12 weeks of BOSU balance with strength training in patients with an isolated PCL injury, the functional outcome, proprioception, and isokinetic muscle strength were significantly improved, and comparable to the contralateral normal leg and the post-PCL reconstruction group. We suggest that programs combining BOSU balance and strength training should be introduced in patients with a PCL injury to promote positive clinical results.

Arthroscopic Reconstruction of the Posterior Cruciate Ligament with a Ligament-advanced Reinforcement System and Hamstring Tendon Autograft: A Retrospective Study

OBJECTIVE

Both ligament-advanced reinforcement system (LARS) and hamstring tendon autograft can serve as grafts for posterior cruciate ligament (PCL) reconstruction. However, few studies have compared the effectiveness of these two approaches. This study therefore aimed to compare the clinical efficacy of arthroscopic reconstruction of the PCL using either the LARS or hamstring tendon autograft.

METHODS

A total of 36 patients who underwent PCL reconstruction were retrospectively analyzed. Within this cohort, 15 patients received a reconstruction using the LARS (LARS group) and 21 using the hamstring tendon autograft (HT group).

RESULTS

The pre- and post-operative subjective scores and knee stability were evaluated and the patients were followed up for a period of 2 to 10.5 years (4.11±2.0 years on average). The last follow-up showed that functional scores and knee stability were significantly improved in both groups (P<0.05). Six months after operation, Lysholm scores and IKDC subjective scores were higher in the LARS group than in the HT group (P<0.05). Nonetheless, the last follow-up showed no significant differences in the functional scores or the posterior drawer test between the two groups (P>0.05). In the LARS and HT groups, 12 and 9 patients, respectively exhibited KT1000 values <3 mm, with the difference being statistically significant (P<0.05). In the HT group, the diameter of the four-strand hamstring tendon was positively correlated with height (P<0.05), which was 7.37±0.52 mm in males and 6.50±0.77 mm in females (P<0.05).

CONCLUSION

Both LARS and hamstring tendon approaches achieved good efficacy for PCL reconstruction, but patients in the LARS group exhibited faster functional recovery and better knee stability in the long term. LARS is especially suitable for those who hope to resume activities as early as possible.

Outcomes of Pediatric Posterior Cruciate Ligament Reconstruction: A Systematic Review

Background

Little has been reported in the literature regarding surgical treatment of posterior cruciate ligament (PCL) injuries in pediatric patients.

Purpose/Hypothesis

The purpose was to evaluate presentation, injury pattern, outcomes, and complications of surgically managed PCL injuries in pediatric patients. It was hypothesized that pediatric patients would have good patient-reported outcomes and no significant radiographic changes or complications.

Study Design

Systematic review; Level of evidence, 4.

Methods

A literature search was performed using PubMed, Medline, EMBASE, Scopus, and Cochrane databases between 1975 and December 16, 2019. Search terms included "posterior cruciate ligament," "peel-off injury," "avulsion," "PCL," "pediatric," "skeletally immature," and "adolescent." Included were studies on pediatric patients with PCL injuries managed operatively. Exclusion criteria included case reports, studies not reporting clinical results, reviews, abstract or conference papers, or papers not in the English language. Quality assessment was performed on all included studies using the MINORS (Methodological Index for Non-Randomized Studies) criteria.

Results

Four articles comprising 43 knees in 42 patients met the criteria and were included. Motor vehicle accidents were the most common mechanism of injury (39.5%; n = 17/43), followed by sports-related injuries (35%; n = 15/43). All studies commented on tear pattern, with the following distribution: 42% (n = 18/43) midsubstance tears, 37% (n = 16/43) tibial avulsions, and 21% (n = 9/43) femoral avulsions. Overall, good patient-reported outcomes (Knee injury and Osteoarthritis Outcome Score and Pediatric International Knee Documentation Committee, Tegner, and Lysholm scores) and return to activity, as well as satisfactory posterior stability (KT-1000 arthrometer, posterior drawer test, and kneeling radiographs) and range of motion, were reported. There was no significant leg-length discrepancy or angular deformity reported. Arthrofibrosis was reported in 7% of postoperative knees and was the most commonly reported complication. Osteoarthritis was reported in 21% (n = 9/43) of knees. The average MINORS score was 7 (range, 6-8) for noncomparative studies and 10 for comparative studies.

Conclusion

Good patient-reported outcomes and return to activity can be obtained using repair or reconstruction. This evidence was limited by the quality of the included studies and overall small sample size; however, this review serves as a baseline for futures studies on PCL repair/reconstruction in pediatric patients.

Micro- and Macroscale Assessment of Posterior Cruciate Ligament Functionality Based on Advanced MRI Techniques

T2 mapping assesses tissue ultrastructure and composition, yet the association of imaging features and tissue functionality is oftentimes unclear. This study aimed to elucidate this association for the posterior cruciate ligament (PCL) across the micro- and macroscale and as a function of loading. Ten human cadaveric knee joints were imaged using a clinical 3.0T scanner and high-resolution morphologic and T2 mapping sequences. Emulating the posterior drawer test, the joints were imaged in the unloaded (δ0) and loaded (δ1) configurations. For the entire PCL, its subregions, and its osseous insertion sites, loading-induced changes were parameterized as summary statistics and texture variables, i.e., entropy, homogeneity, contrast, and variance. Histology confirmed structural integrity. Statistical analysis was based on parametric and non-parametric tests. Mean PCL length (37.8 ± 1.8 mm [δ0]; 44.0 ± 1.6 mm [δ1] [p < 0.01]), mean T2 (35.5 ± 2.0 ms [δ0]; 37.9 ± 1.3 ms [δ1] [p = 0.01]), and mean contrast values (4.0 ± 0.6 [δ0]; 4.9 ± 0.9 [δ1] [p = 0.01]) increased significantly under loading. Other texture features or ligamentous, osseous, and meniscal structures remained unaltered. Beyond providing normative T2 values across various scales and configurations, this study suggests that ligaments can be imaged morphologically and functionally based on joint loading and advanced MRI acquisition and post-processing techniques to assess ligament integrity and functionality in variable diagnostic contexts.

Diagnostic Algorithm in Patients with Flexion Instability after Cruciate-Retaining Total Knee Arthroplasty: A Case Report

A posterior flexion instability due to insufficiency of the posterior cruciate ligament (PCL) in cruciate retaining (CR) total knee arthroplasty (TKA) is an important but underdiagnosed problem. We hereby suggest a diagnostic algorithm, as demonstrated by a case report of a male patient suffering from anterior knee pain and instability after CR TKA. Clinical examination was followed by standard anterior–posterior and lateral radiographs. Stress radiographs in 30° and 90° posterior drawer position enabled a dynamic examination of the instability. SPECT/CT was used to determine the TKA component position in all planes and investigate bone tracer uptake (BTU) patterns. At revision surgery, an absent PCL after CR TKA was noted and a semi-constrained TKA was implanted.

The Disproportionate Increase of the Intraoperative Flexion and Extension Gap Space after Posterior Cruciate Ligament Resection in Total Knee Arthroplasty

Purpose: Maintaining gap balance is critical for total knee arthroplasty (TKA). This study aimed to elucidate if the extension–flexion gaps would be changed with posterior cruciate ligament (PCL) intact (PI) and PCL resection (PR) during TKA. The flexion gaps were measured using two methods, open-(Fo) and closed-chain position (Fc), based on the definition of kinetic chain position, respectively. Methods: This retrospective study enrolled a total of 33 patients who underwent posterior-stabilized (PS) TKA for symptomatic advanced osteoarthritis of knees. After bone cuts were completed, the extension–flexion gaps before and after PCL resection during TKA were measured using a calibrated tensioning device set at a 100 Nm distraction force. To further differentiate the effect of thigh weight on the 90° flexion gap, two varied methods of examination, either in closed chain (Fc) or open chain (Fo) were performed. Results: The increases in the 90° knee flexion gap after PCL resection were measured by both methods, i.e., ΔFc (PR-Fc—PI-Fc): 2.04 ± 2.06 mm, p < 0.001; and mean ΔFo (PR-Fo—PI-Fo): 1.64 ± 1.36 mm, p < 0.001. However, there were no differences between ΔFc and ΔFo before and after PCL resection. A greater amount of flexion gap was identified in open chain than in closed chain after PCL resection, and the PR-Fo and PR-Fc were 14.36 ± 3.13 and 11.40 ± 3.47 (p < 0.001), respectively. Conclusions: The resection of PCL during TKA distinctly increased the flexion gap, but not the extension gap. This disproportionate increase of the gap will cause a gap balance mismatch. The tensioning maneuver in open-chain was more effective to detect the gap differences than in closed-chain before and after PCL resection during TKA.

Does Posterior Cruciate Ligament Retention or Sacrifice in Total Knee Replacement Affect Proprioception? A Systematic Review

Background: Proprioception is an important part of the somatosensory system involved in human motion control, which is fundamental for activities of daily living, exercise, and sport-specific gestures. When total knee arthroplasty (TKA) is performed, the posterior cruciate ligament (PCL) can be retained, replaced, or discarded. The PCL seems to be responsible for maintaining the integrity of the joint position sense (JPS) and joint kinesthesia. The aim of this review was to assess the effect of PCL on knee joint proprioception in total knee replacement. Methods: This systematic review was conducted within five electronic databases: PubMed, Scopus, Web of Science, Cochrane, and PEDro with no data limit from inception to May 2021. Results: In total 10 publications were evaluated. The analysis was divided by proprioception assessment method: direct assessment (JPS, kinesthesia) and indirect assessment (balance). Conclusions: The current evidence suggest that the retention of the PCL does not substantially improve the joint proprioception after TKA. Due to the high heterogeneity of the studies in terms of design, proprioception outcomes, evaluation methods, further studies are needed to confirm the conclusions. In addition, future research should focus on the possible correlation between joint proprioception and walking function.