No Clinically Important Difference in Knee Scores or Instability Between Transtibial and Inlay Techniques for PCL Reconstruction: A Systematic Review

Bicruciate Reconstruction with Bilateral Hamstring Autografts: Technique and Functional Results

Objective  The purpose of this study was to evaluate the clinical and functional results of simultaneous reconstruction of the ACL and PCL with bilateral hamstring autografts. We hypothesized that this reconstruction technique results in less morbidity and has similar results to the ones published in the previous literature. Methods  Eighteen patients with bicruciate lesions were selected and treated by arthroscopic surgery with autologous hamstring tendons in a single-stage procedure. The thicker semitendinosus tendon (ST) and the two gracilis tendons (G) were used for a 6-strand PCL reconstruction. The thinner ST was used for a 3-strand ACL reconstruction. The average patient age at surgery was 31 years, and the minimum follow-up was 2 years. Function of the operated knee was evaluated according to the Lysholm scale. Anterior knee laxity was examined with a KT-1000 arthrometer. Posterior laxity was evaluated using stress radiographies. Results  Statistically significant improvements were found for all three measurements ( p  < 0.001). Knee function by the Lysholm score increased from 43.8 ± 4.1 to 89.9 ± 3.8 post-surgery. The average anterior knee laxity improved from 5.2 + -0.8 mm initially to 2.4 + - 0.5 mm post-surgery. The posterior translation of the tibia relative to the femur decreased from 10 ± 3.4 mm to 3 ± 1.6 mm post-surgery. No patient showed loss of motion in extension or knee flexion. Conclusion  The simultaneous bicruciate reconstruction with bilateral hamstring autograft is a valuable option to achieve good functional outcomes and ligamentous stability.

Suture Tape Augmentation Improves Posterior Stability After Isolated Posterior Cruciate Ligament Reconstruction Using Hamstring Tendon Autograft With Single-Bundle Transtibial Technique

PURPOSE

To assess whether posterior cruciate ligament reconstruction (PCLR) with suture tape augmentation can yield more stability after isolated PCLR.

METHODS

A prospective database was retrospectively reviewed to identify patients who underwent primary isolated PCLR (control group) or isolated PCLR with suture tape augmentation (study group) from January 2016 to September 2020. We analyzed subjective International Knee Documentation Committee (IKDC), Lysholm, and Tegner knee scores; posterior drawer test findings; posterior stress radiographs; and return-to-sports activity rates. The minimal clinically important difference (MCID) was used to evaluate clinical relevance (subjective IKDC, Lysholm, and Tegner scores).

RESULTS

A total of 59 patients were included in this analysis (28 in control group and 31 in study group). The average length of follow-up was similar between the study and control groups (48.6 months vs 47.9 months, P = .800). Knee function was significantly improved in the study group in terms of subjective IKDC scores (85.1 ± 6.4 in study group vs 79.8 ± 6.4 in control group, P = .002), Lysholm scores (86.3 ± 7.4 vs 80.8 ± 7.4, P = .005), and Tegner scores (7.0 ± 1.4 vs 5.6 ± 1.7, P = .006). However, the differences between the control and study groups were less than the MCID for the subjective IKDC score and Lysholm score. In the control and study groups, 21.4% of patients (6 of 28) and 48.4% of patients (15 of 31), respectively, returned to their preinjury sports activity levels (P = .031). At last follow-up, the mean side-to-side difference in posterior laxity was significantly improved in the study group compared with the control group (1.52 ± 0.70 mm in study group vs 3.17 ± 2.01 mm in control group, P < .01).

CONCLUSIONS

Primary isolated PCLR with suture tape augmentation provides better posterior stability than PCLR without suture tape augmentation at a minimum of 2 years' follow-up. No differences between the groups were observed in the percentage of patients who met or exceeded the MCID for the subjective IKDC and Lysholm scores.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Surgical approach on combined chronic patellar tendon and bicruciate knee ligament injury

A combined injury of the patellar tendon and both the anterior and posterior cruciate ligaments is disabling. It directly affects knee kinematics and biomechanics, presenting a considerable surgical challenge. In this complex and uncommon injury, decision-making should take into account the surgeon's experience and consider one- or two-stage surgery, tendon graft, graft fixation, and rehabilitation protocol. This manuscript discusses the surgical approach based on a comprehensive understanding of the patellar tendon and bicruciate biomechanics to guide which structures should be reconstructed first, especially when a two-stage procedure is chosen.

Suture Tape Augmentation of Posterior Cruciate Ligament Reconstruction Shows Improved Biomechanical Stability With Equivalent Outcome and Complication Rates: A Scoping Review

PURPOSE

To assess the current literature surrounding suture tape augmentation (STA) of posterior cruciate ligament reconstruction (PCLR) with additional evaluation of PCLR+STA in clinical practice.

METHODS

A systematic search of 3 databases (PubMed, EMBASE, and Web of Science Core Collection) was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and was completed in April 2023 to identify studies related to PCLR+STA. Surgical technique, animal, biomechanical, and clinical studies were included for review with quality appraisal conducted according to study design.

RESULTS

A total of 380 articles were identified in the search, 6 of which met inclusion criteria. Biomechanical studies showed a significant reduction in posterior tibial translation with STA of PCLR in multiple studies. STA was found to decrease total elongation by 45% to 58% in multiple studies; increased load to failure was seen with STA as well in 1 study. Clinical studies showed equivalent or improved patient-reported outcomes with STA of PCLR compared with PCLR alone.

CONCLUSIONS

Biomechanical studies offer evidence showing the beneficial load-sharing properties of STA such as increased strength and ultimate load with decreased elongation of the graft, especially with larger forces. Clinical evidence illustrates improved or equivalent patient-reported outcomes to standard PCLR with no difference in complication rate.

CLINICAL RELEVANCE

STA of PCLR offers an opportunity to improve initial graft stability during the early healing phase through load sharing between the augmentation and the graft.

Outcomes after Anatomic Double-Bundle Posterior Cruciate Ligament Reconstructions Using Transtibial and Tibial Inlay Techniques

Surgical reconstruction is recommended for symptomatic posterior cruciate ligament (PCL) deficiency. While anatomic double-bundle PCL reconstruction (PCLR) has been reported to be associated with biomechanical and clinical advantages over other methods, there is still debate regarding the optimal technique for tibial positioning and fixation. Based on reported advantages and disadvantages, we employed two tibial fixation techniques, transtibial (TT) and tibial inlay (TI) for anatomic double-bundle PCLR with technique selection based on body mass index, comorbidities, and primary versus revision surgery. This study aimed to compare clinical outcomes following PCLR utilizing either TT or TI techniques to validate relative advantages, disadvantages, and indications for each based on the review of prospectively collected registry data. For 37 patients meeting inclusion criteria, 26 underwent arthroscopic TT PCLR using all-soft- tissue allograft with suspensory fixation in the tibia and 11 patients underwent open TI PCLR using an allograft with calcaneal bone block and screw fixation in the tibia. There were no significant preoperative differences between cohorts. Success rates were 96% for TT and 91% for TI with all successful cases documented to be associated with good-to-excellent posterior stability and range of motion in the knee at the final follow-up. In addition, patient-reported outcome scores were within clinically meaningful ranges for pain, function, and mental health after PCLR in both cohorts, suggesting similarly favorable functional, social, and psychological outcomes. Patient-reported pain scores at 6 months postoperatively were significantly (p = 0.042) lower in the TT cohort, which was the only statistically significant difference in outcomes noted. The results of this study support the use of TT and TI techniques for double-bundle anatomic PCLR in restoring knee stability and patient function when used for the treatment of isolated and multiligamentous PCL injuries. The choice between tibial fixation methods for PCLR can be appropriately based on patient and injury characteristics that optimize respective advantages for each technique.

The optimal tibial tunnel placement to maximize the graft bending angle in the transtibial posterior cruciate ligament reconstruction: a quantitative assessment in three-dimensional computed tomography model

Background

The graft bending angle created by the graft and the tibial tunnel has inevitably occurred during the transtibial posterior cruciate ligament (PCL) reconstruction. However, few studies quantitively analyzed this angle. This study aimed to (I) explore the optimal tibial tunnel placement to maximize the graft bending angle in the PCL reconstruction; (II) reveal the effect of the tibial tunnel placement on the graft bending angle.

Methods

This was an in-vitro surgical simulation study based on the three-dimensional (3D) computed tomography (CT). A total of 55 patients who took CT scanning for knee injuries were selected (April 2020 to January 2022) from the local hospital database for review. The 3D knee models were established on the Mimics software based on the knees' CT data. Using the Rhinoceros software to simulate the transtibial PCL reconstruction on the 3D CT knee model. The anteromedial and anterolateral tibial tunnel approaches were simulated with different tibial tunnel angle. The graft bending angle and tibial tunnel length (TTL) with different tibial tunnel angles were quantitively analyzed.

Results

The graft bending angle in anterolateral approach with a 50° tibial tunnel angle was significantly greater than it in anteromedial approach with a 60° tibial tunnel angle (P<0.001). There was no difference of the graft bending angle between the anterolateral approach with a 40° tibial tunnel angle and the anteromedial approach with a 60° tibial tunnel angle (P>0.05). The graft bending angle showed a strong correlation with the tibial tunnel angle (for anteromedial approach: r=0.759, P<0.001; for anterolateral approach: r=0.702, P<0.001). The best-fit equation to calculate the graft bending angle based on the tibial tunnel angle was Y = 0.89*X + 59.05 in anteromedial tibial tunnel approach (r2=0.576), and was Y = 0.78*X + 80.21 anterolateral tibial tunnel approach (r2=0.493).

Conclusions

The graft bending angle and TTL will significantly increase as the tibial tunnel angle becomes greater. Maximizing the tibial tunnel angle (50° tibial tunnel angle) in the anterolateral approach could provide the greatest graft bending angle in the PCL reconstruction. No matter how the tibial tunnel angle is changed in the anteromedial approach, using anterolateral approach might reduce the killer turn effect more effectively than using anteromedial approach.

Outcome of Arthroscopic All-Inside Posterior Cruciate Ligament Reconstruction Using the Posterior Trans-Septal Approach

Introduction

Posterior Cruciate Ligament (PCL) reconstruction is a complex surgical procedure and often challenging. The newer posterior trans-septal portal technique is thought to make tibial tunnel preparation easier with better visualization of the tibial attachment site. It is also thought to lower the risk of neurovascular injuries. The aim of this study was to evaluate the functional and clinical outcomes of patients who underwent arthroscopic all-inside PCL reconstruction using the posterior trans-septal portal at our institute.

Methods

This was a retrospective study with prospectively collected data between 2016 and 2020. Data collected were age, gender, types of graft used, range of movement, posterior drawer test grade, KOOS score, Lysholm knee scoring scale, and post-operative complications. All patients underwent pre- and post-operative PCL rehabilitation.

Results

A total of 36 patients (26 males and 10 females) were identified from our database. The mean age was 35.2 years. Mean time from injury to surgery was 20 months. Mean follow-up was 41.2 months (range, 13-72 months). Twenty cases involved multi-ligament injuries and another 16 patients had isolated PCL injury. Post-operative mean posterior drawer test grade improved from 2.7 to 0.7 (p < 0.001). Knee range of movement was 116.3 degrees pre-operatively and 115.6 degrees postoperatively (p = 0.814). Lysholm knee scoring scale improved from 50.9 to 91.0 (p < 0.001). KOOS score improved from 65.1 to 77.2 (p = 0.196). One patient required manipulation under anesthesia for stiffness. No patients needed any additional surgical procedures. All PCLs were clinically intact at the final follow-up.

Conclusion

Greater visualization of the PCL tibial attachment minimizes the 'killer turn' giving a huge advantage to this technique. Arthroscopic all-inside PCL reconstruction using the posterior trans-septal portal technique is a safe, reliable and reproducible procedure. From our study, it shows that post-operative clinical and functional outcomes improved significantly.

Postless Tape Augmentation for Posterior Cruciate Ligament Reconstruction

Many techniques have been described for posterior cruciate ligament (PCL) reconstruction, but residual laxity remains an ongoing challenge. Suture or tape augmentation during ligament reconstruction has become a popular option to prevent graft elongation but comes at the expense of additional costs due to implants for augment fixation, and concern for stress shielding of the graft if the augment and graft are not equally tensioned. We introduce a technique for postless tape augmentation during allograft PCL reconstruction that allows for equal tensioning of graft and augment through the use of a sheath and screw construct without the need for additional implants for augment fixation.

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.

Global variation in isolated posterior cruciate ligament reconstruction

Purpose

In the setting of persistent instability or failed non-operative management, surgical reconstruction is commonly recommended for isolated posterior cruciate ligament (PCL) tears. The purpose of this study was to systematically review published studies to evaluate regional variation in the epidemiology of and surgical approaches to primary, isolated PCL reconstruction.

Methods

A systematic review was performed in June 2022 to identify studies examining operative techniques during primary, isolated PCL reconstruction. Collected variables consisted of reconstruction technique, graft type, graft source, tibial reconstruction technique, femoral and tibial drilling and fixation methods, and whether the remnant PCL was preserved or debrided. Studies were classified into four global regions: Asia, Europe, North America, and South America.

Results

Forty-five studies, consisting of 1461 total patients, were identified. Most of the included studies were from Asia (69%, n = 31/45). Single bundle reconstruction was more commonly reported in studies out of Asia, Europe, and North America. Hamstring autografts were utilized in 51.7% (n = 611/1181) of patients from Asia and 60.8% (n = 124/204) of patients from Europe. Trans-tibial drilling and outside-in femoral drilling were commonly reported in all global regions. The PCL remnant was generally debrided, while remnant preservation was commonly reported in studies from Asia.

Conclusion

Surgical treatment of isolated PCL injuries varies by region, with the majority of published studies coming from Asia. Single-bundle reconstruction with hamstring autograft through a trans-tibial approach is the most commonly reported technique in the literature, with males reported to undergo isolated reconstruction more often than females.

Level of Evidence

Systematic review, Level IV.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40634-022-00541-4.

Good clinical and radiological results following remnant-preserving posterior cruciate ligament reconstruction: a systematic review

PURPOSE

The objective of this systematic literature review was to report the results and complications of recent remnant preservation techniques in posterior cruciate ligament (PCL) reconstruction.

METHODS

A systematic review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Two independent reviewers searched the PubMed, Scopus, Embase, and Cochrane Library databases using the terms "posterior cruciate ligament" or "PCL" and "remnant preserving." The outcome measures extracted from the studies were the Lysholm score, the International Knee Documentation Committee's (IKDC) subjective and objective scores, Tegner scores, Orthopädische Arbeitsgruppe Knie (OAK) rate of return to sports, and rate of complications. Data were also extracted from studies that used stress radiographs to perform a quantitative assessment of the preoperative and postoperative anteroposterior stability.

RESULTS

The systematic review included 13 studies. The patient cohort of consisted of 643 participants (544 [84.6%] men and 99 [15.4%] women) with a mean age of 32.9 ± 4.0 years. The mean postoperative follow-up was 34.5 ± 10.9 months (range: 24-96 months), while the mean time from injury to surgery was 14.4 ± 9.9 months (range: 0-240 months). All studies reported clinically significant improvement at final follow-up, as evident from the measured subjective and objective IKDC scores, Lysholm score, Tegner score, and OAK rate. Only three studies reported return to sports activity, with a mean percentage of 90.8% (99/109). All studies showed a significant improvement in posterior translation, from 11.5 ± 1.2 mm to 3.3 ± 1.1 mm, using radiography (side-to-side difference). This systematic review revealed 13 (2.0%) failures and 33 (5.1%) minor complications: 10 (1.6%) cases of stiffness, 21 (4.9%) screws removal, 1 (0.2%) injury of the peroneal nerve, and 1 (0.2%) fibular fracture.

CONCLUSIONS

With the currently available data, all studies included in the review on posterior cruciate ligament reconstruction with remnant preservation demonstrated satisfactory outcomes at mid-term follow-up (> 24 months), despite varying surgical techniques and graft types, and intervals from injury to surgery. For clinical relevance, standard PCL reconstruction is a highly effective operation in terms of improvement in functional status, knee stability, quality of life, and cost effectiveness. The remnant preservation technique requires more comprehensive diagnostic assessments of the PCL remnant patterns and more complicated surgical procedures. Given the absence so far of high quality studies with long-term follow-up, the remnant-preserving techniques should be recommended only by experienced knee arthroscopic surgeons.

LEVEL OF EVIDENCE

Level IV.

STUDY REGISTRATION

reviewregistry1376- www.researchregistry.com .

3D Killer Turn Angle in Transtibial Posterior Cruciate Ligament Reconstruction Is Determined by the Graft Turning Angle both in the Sagittal and Coronal Planes

Objective

During the transtibial posterior cruciate ligament (PCL) reconstruction, surgeons commonly pay more attention to the graft turning angle in the sagittal plane (GASP), but the graft turning angle in the coronal plane (GACP) is always neglected. This study hypothesized that the three‐dimensional (3D) killer turn angle was determined by both the GASP and GACP, and aimed to quantitively analyze the effects of the GASP and GACP on the 3D killer turn angle.

Methods

This was an in‐vitro computer simulation study of transtibial PCL reconstruction using 3D knee models. Patients with knee injuries who were CT scanned were selected from the CT database (April 2019 to January 2021) at a local hospital for reviewing. A total of 60 3D knees were simulated based on the knees' CT data. The femoral and tibial PCL attachment were located on the 3D knee model using the Rhinoceros software. The tibial tunnels were simulated based on different GASP and GACP. The effects of the GASP and GACP on the 3D killer turn angle were quantitatively analyzed. One‐way analysis of variance was used to compare the outcomes in different groups. The regression analysis was performed to identify variables of the GASP and GACP which significantly affected 3D killer turn angle.

Results

The 3D killer turn angle showed a significant proportional relationship not only with the GASP (r² > 0.868, P < 0.001), but also with the GACP (r² > 0.467, P < 0.001). Every 10° change of the GACP caused 2.8° to 4.4° change of the 3D killer turn angle, whereas every 10° change of the GASP caused 6.4° to 9.2° change of the 3D killer turn angle.

Conclusions

The 3D killer turn angle was significantly affected by both the GASP and GACP. During the transtibial PCL reconstruction, the proximal anterolateral tibial tunnel approach could increase the 3D killer turn angle more obviously compared with the most distal anteromedial tibial tunnel approach. To minimize the killer turn effect, both the GASP and GACP were required to be considered to increase.

What Is the Maximum Tibial Tunnel Angle for Transtibial PCL Reconstruction? A Comparison Based on Virtual Radiographs, CT Images, and 3D Knee Models

BACKGROUND

To minimize the killer turn caused by the sharp margin of the tibial tunnel exit in transtibial PCL reconstruction, surgeons tend to maximize the angle of the tibial tunnel in relation to the tibial plateau. However, to date, no consensus has been reached regarding the maximum angle for the PCL tibial tunnel.

QUESTIONS/PURPOSES

In this study we sought (1) to determine the maximum tibial tunnel angle for the anteromedial and anterolateral approaches in transtibial PCL reconstruction; (2) to compare the differences in the maximum angle based on three measurement methods: virtual radiographs, CT images, and three-dimensional (3D) knee models; and (3) to conduct a correlation analysis to determine whether patient anthropomorphic factors (age, sex, height, and BMI) are associated with the maximum tibial tunnel angle.

METHODS

Between January 2018 and December 2020, 625 patients who underwent CT scanning for knee injuries were retrospectively reviewed in our institution. Inclusion criteria were patients 18 to 60 years of age with a Kellgren-Lawrence grade of knee osteoarthritis less than 1 and CT images that clearly showed the PCL tibial attachment. Exclusion criteria were patients with a history of tibial plateau fracture, PCL injuries, tumor, and deformity around the knee. Finally, 104 patients (43 males and 61 females, median age: 38 [range 24 to 56] years, height: 165 ± 9 cm, median BMI: 23 kg/cm2 [range 17 to 31]) were included for analysis. CT data were used to create virtual 3D knee models, and virtual true lateral knee radiographs were obtained by rotating the 3D knee models. Virtual 3D knee models were used as an in vitro standard method to assess the true maximum tibial tunnel angle of anteromedial and anterolateral approaches in transtibial PCL reconstruction. The tibial tunnel's entry was placed 1.5 cm anteromedial and anterolateral to the tibial tubercle for the two approaches. To obtain the maximum angle, a 10-mm- diameter tibial tunnel was simulated by making the tibial tunnel near the posterior tibial cortex. The maximum tibial tunnel angle, tibial tunnel lengths, and perpendicular distances of the tunnel's entry point to the tibial plateau were measured on virtual radiographs, CT images, and virtual 3D knee models. One-way ANOVA was used to compare the differences in the maximum angle among groups, and correlation analysis was performed to identify the relationship of the maximum angle and anthropomorphic factors (age, sex, height, and BMI).

RESULTS

The maximum angle of the PCL tibial tunnel relative to the tibial plateau was greater in the anteromedial group than the anterolateral group (58° ± 8° versus 50° ± 8°, mean difference 8° [95% CI 6° to 10°]; p < 0.001). The maximum angle of the PCL tibial tunnel was greater in the virtual radiograph group than the CT image (68° ± 6° versus 49° ± 5°, mean difference 19° [95% CI 17° to 21°]; p < 0.001), the anteromedial approach (68° ± 6° versus 58° ± 8°, mean difference 10° [95% CI 8° to 12°]; p < 0.001), and the anterolateral approach (68° ± 6° versus 50° ± 8°, mean difference 18° [95% CI 16° to 20°]; p < 0.001), but no difference was found between the CT image and the anterolateral groups (49° ± 5° versus 50° ± 8°, mean difference -1° [95% CI -4° to 1°]; p = 0.79). We found no patient anthropomorphic characteristics (age, sex, height, and BMI) that were associated with the maximum angle.

CONCLUSION

Surgeons should note that the mean maximum angle of the tibial tunnel relative to the tibial plateau was greater in the anteromedial than anterolateral approach in PCL reconstruction, and the maximum angle might be overestimated on virtual radiographs and underestimated on CT images.

CLINICAL RELEVANCE

To perform PCL reconstruction more safely, the findings of this study suggest that the PCL drill system should be set differently for the anteromedial and anterolateral approaches, and the maximum angle measured by intraoperative fluoroscopy should be reduced 10° for the anteromedial approach and 18° for the anterolateral approach. Future clinical or cadaveric studies are needed to validate our findings.

The Permissive Safe Angle of the Tibial Tunnel in Transtibial Posterior Cruciate Ligament Reconstruction: A Three-Dimensional Simulation Study

Objective

To determine the permissive safe angle (PSA) of the tibial tunnel in transtibial posterior cruciate ligament (PCL) reconstruction based on a three‐dimensional (3D) simulation study.

Methods

This was a computer simulation study of transtibial PCL reconstruction using 3D knee models. CT images of 90 normal knee joints from 2017 to 2020 were collected in this study, and 3D knee models were established based on CT data. The tunnel approaches were subdivided into the anterior 1/3 of the anteromedial tibia (T1), middle 1/2 of the anteromedial tibia (T2), the tibial crest (T3), anterior 1/3 of the anterolateral tibia (T4), middle 1/2 of the anterolateral tibia (T5). Five tibial tunnels (T1–T5) were simulated on the 3D knee models. The PSAs, in different tibial tunnel approaches were measured, and subgroup analyses of sex, age and height were also carried out.

Results

The mean PSAs of the tibial tunnels with 5 different approaches (T1–T5) were 58.49° ± 6.82°, 61.14° ± 6.69°, 56.12° ± 7.53°, 52.01° ± 8.89° and 49.90° ± 10.53°, respectively. The differences of the mean PSAs between the anteromedial and anterolateral approaches were significant (P < 0.05). However, there was no significant difference of the mean PSA value between the two anteromedial tibial tunnel approaches (T1–T2) (P > 0.05), as well as between the two anterolateral tibial tunnel approaches (T4–T5). The patient's anthropomorphic characteristics of sex, age, and height were not associated with the PSAs.

Conclusions

The PSA varied with the anteromedial, tibial crest and anterolateral approaches for transtibial PCL reconstruction, and surgeons should limit the PCL drill guide by referring to the specific PSA for different surgical approaches.

Axial But Not Sagittal Hinge Axis Affects Posterior Tibial Slope in Medial Open-Wedge High Tibial Osteotomy: A 3-Dimensional Surgical Simulation Study

PURPOSE

The purpose of this 3-dimensional (3D) surgical simulation study was to investigate the effects of axial and sagittal hinge axes (hinge axes in the axial and sagittal planes) on medial and lateral posterior tibial slope (PTS) in medial open-wedge high tibial osteotomy (OWHTO), and evaluate the quantitative relationship between hinge axis and PTS change.

METHODS

Preoperative computed tomography data from patients with varus knee deformity were collected. A standard hinge axis (0°) and 12 different hinge axes (6 axial hinge axes and 6 sagittal hinge axes: ±10°, ±20°, and ±30°) were defined in a 3D surgical simulation of OWHTO using a bone model. The differences between before and after simulation surgery in medial and lateral PTS, medial proximal tibial angle, opening gap, and opening wedge angle were measured.

RESULTS

In total, 93 varus knees in 93 patients were included for study. Compared with the standard hinge axis, axial hinge axis significantly affected medial and lateral PTS (P < .001). In contrast, sagittal hinge axis had no significant effect on medial and lateral PTS (P > .05). Every 10° change in axial hinge axis with a mean coronal valgus correction of 10° might result in approximately 1.6° of alteration in PTS. Stepwise regression analysis showed that axial hinge axis is the most significant factors affecting PTS (β coefficient = 0.78, P < .001), followed by opening wedge angle (β coefficient = 0.36, P < .001) and gap ratio (β coefficient = 0.12, P < 0.001).

CONCLUSION

Based on our findings of 3D OWHTO simulation, axial hinge axis significantly influences medial and lateral PTS in OWHTO, but sagittal hinge axis has no effect on change in PTS. Every 10° change of axial hinge axis with a 10° coronal valgus correction caused approximately 1.6° change of PTS.

CLINICAL RELEVANCE

Hinge axis in the axial plane significantly affects PTS, but hinge axis in the sagittal plane has no effect on PTS. To maintain PTS, surgeons should make hinge axis at the true lateral position of the tibia in the axial plane. To intentionally alter PTS, an anterolateral axial hinge axis could be used to decrease PTS or a posterolateral axial hinge axis could be used to increase PTS. Opening wedge angle or gap ratio is also useful for intentional modification of PTS.

Comparable Clinical and Radiologic Outcomes Between an Anatomic Tunnel and a Low Tibial Tunnel in Remnant-Preserving Posterior Cruciate Ligament Reconstruction

Background:

There is currently no consensus on the optimal placement of the tibial tunnel for remnant-preserving posterior cruciate ligament (PCL) reconstruction.

Purpose/Hypothesis:

The purpose of this study was to compare the clinical and radiologic outcomes of remnant-preserving PCL reconstruction using anatomic versus low tibial tunnels. We hypothesized that the outcomes of low tibial tunnel placement would be superior to those of anatomic tibial tunnel placement at the 2-year follow-up after remnant-preserving PCL reconstruction.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

We retrospectively reviewed the data for patients who underwent remnant-preserving PCL reconstruction between March 2011 and January 2018 with a minimum follow-up of 2 years (N = 63). On the basis of the tibial tunnel position on postoperative computed tomography, the patients were divided into those with anatomic placement (group A; n = 31) and those with low tunnel placement (group L; n = 32). Clinical scores (International Knee Documentation Committee subjective score, Lysholm score, and Tegner activity level), range of motion, complications, and stability test outcomes at follow-up were compared between the 2 groups. Graft signal on 1-year follow-up magnetic resonance imaging scans was compared between 22 patients in group A and 17 patients in group L.

Results:

There were no significant differences between groups regarding clinical scores or incidence of complications, no between-group differences in posterior drawer test results, and no side-to-side difference on Telos stress radiographs (5.2 ± 2.9 mm in group A vs 5.1 ± 2.8 mm in group L; P = .900). Postoperative 1-year follow-up magnetic resonance imaging scans showed excellent graft healing in both groups, with no significant difference between them.

Conclusion:

The clinical and radiologic outcomes and complication rate were comparable between anatomic tunnel placement and low tibial tunnel placement at 2-year follow-up after remnant-preserving PCL reconstruction. The findings of this study suggest that both tibial tunnel positions are clinically feasible for remnant-preserving PCL reconstruction.

Evolving evidence in the treatment of primary and recurrent posterior cruciate ligament injuries, part 2: surgical techniques, outcomes and rehabilitation

Isolated and combined posterior cruciate ligament (PCL) injuries are associated with severe limitations in daily, professional, and sports activities as well as with devastating long-term effects for the knee joint. As the number of primary and recurrent PCL injuries increases, so does the body of literature, with high-quality evidence evolving in recent years. However, the debate about the ideal treatment approach such as; operative vs. non-operative; single-bundle vs. double-bundle reconstruction; transtibial vs. tibial inlay technique, continues. Ultimately, the goal in the treatment of PCL injuries is restoring native knee kinematics and preventing residual posterior and combined rotatory knee laxity through an individualized approach. Certain demographic, anatomical, and surgical risk factors for failures in operative treatment have been identified. Failures after PCL reconstruction are increasing, confronting the treating surgeon with challenges including the need for revision PCL reconstruction. Part 2 of the evidence-based update on the management of primary and recurrent PCL injuries will summarize the outcomes of operative and non-operative treatment including indications, surgical techniques, complications, and risk factors for recurrent PCL deficiency. This paper aims to support surgeons in decision-making for the treatment of PCL injuries by systematically evaluating underlying risk factors, thus preventing postoperative complications and recurrent knee laxity. LEVEL OF EVIDENCE: V.

Successful reconstruction of the posterior cruciate ligament: assessment of posterior cruciate ligament footprints using an objective coordinate system

INTRODUCTION

Anatomic cruciate ligament reconstruction is known to be correlated with better clinical results. The aim of the study was to provide a simple method to enable anatomic results in the setting of PCL reconstruction. We, therefore, assessed the tibial and femoral insertion site of the posterior cruciate ligament (PCL) by the use of an objective coordinate system in an anatomical study. We also sought to show reproducibility of these measurements using intra- and inter-observer coefficients.

MATERIALS AND METHODS

We studied 64 knees, previously preserved according to Thiel's technique. After proper preparation of the articular surfaces of both the tibiae and femora, photographs were taken according to a standardized protocol. PCL footprints were measured by the use of a coordinate system twice by two examiners. We evaluated these measurements by use of the Cohen's kappa inter- and intra-observer coefficient for two observers.

RESULTS

Tibial and femoral measurements of PCL footprints were generated with highly comparable inter- (k = 0.970) and intra-observer (k = 0.992) coefficients and may, therefore, be considered as highly reproducible.

CONCLUSION

Our findings confirmed the reproducibility of defining PCL footprints using a coordinate system and may contribute to planning intraoperative graft-placement to ensure optimal conditions in the upcoming techniques for PCL reconstruction.

Anatomic Double Bundle Posterior Cruciate Ligament Reconstruction Using an Internal Splint

Techniques for reconstruction of posterior cruciate ligament (PCL) tears are rapidly evolving. One problem with current techniques is that laxity may develop early in the postoperative period, leading to relapsed posterior translation of the tibia. Therefore, maintaining tibial reduction during graft incorporation is a target for improvement. We describe using an internal splint to optimize the 4-tunnel, double-bundle allograft PCL reconstruction.

[The killer turn in the posterior cruciate ligament reconstruction: mechanism and improvement]

OBJECTIVE

To summarize the research progress of killer turn in posterior cruciate ligament (PCL) reconstruction.

METHODS

The literature related to the killer turn in PCL reconstruction in recent years was searched and summarized.

RESULTS

The recent studies show that the killer turn is considered to be the most critical cause of graft relaxation after PCL reconstruction. In clinic, this effect can be reduced by changing the fixation mode of bone tunnel, changing the orientation of bone tunnel, squeezing screw fixation, retaining the remnant, and grinding the bone at the exit of bone tunnel. But there is still a lack of long-term follow-up.

CONCLUSION

There are still a lot of controversies on the improved strategies of the killer turn. More detailed basic researches focusing on biomechanics to further explore the mechanism of the reconstructed graft abrasion are needed.

Tibial Inlay Posterior Cruciate Ligament Reconstruction

Reconstruction of the posterior cruciate ligament is typically made through either tibial inlay or transtibial methods. Double-bundle reconstruction can be combined with either technique and has clear biomechanical advantages. On the basis of prior evidence and the author's own surgical experiences, this technique paper provides the reasoning for using these methods. Further evidence and reasoning is given for when to use the inlay technique rather than the transtibial technique for posterior cruciate ligament reconstruction.

Increased Surgical Duration Associated With Prolonged Hospital Stay After Isolated Posterior Cruciate Ligament Reconstruction

Purpose

Although often performed using a variety of reconstructive techniques and strategies, no clinically significant differences presently exist between the approaches available for isolated PCL reconstructions. Given the operatively challenging nature of these procedures, there lies a potentially increased risk of postoperative complications and healthcare expenditures. Our investigation sought to identify patient and surgical risk factors associated with prolonged hospital stays following isolated PCL reconstruction and determine the incidence of 30-day complications after PCL reconstruction using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database.

Method

Patients undergoing isolated PCL reconstructions between 2005 and 2016 were identified in the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database using Current Procedural Terminology codes. Baseline patient and operative characteristics were evaluated as possible risk factors for overnight hospital admissions following PCL reconstruction and analyzed using multivariate analyses.

Results

A total of 249 patients were identified. Multivariate analyses demonstrated that increased operative duration >120 mins (OR 5.04, CI 2.44–10.40; p <0.001) was associated with an increased risk of overnight hospital stay. Major complications occurred in 0.4% (N=1), and minor complications occurred in 0.8% (N=2) with overall complications occurring in 1.2% (N=3) of all patients. Wound dehiscence was the only major complication while superficial surgical site infection and deep vein thrombosis were the only minor complications. 34.1% (N=85) of patients required an overnight hospital stay postoperatively.

Conclusion

Surgical duration >120 mins carried an increased risk of overnight hospital stay after isolated PCL reconstructions. As there are presently minimal significant clinical differences between current PCL reconstruction techniques, improved surgeon familiarity and comfort with a single technique is recommended to decrease operative time and avoid prolonged hospital stays and healthcare expenditures.

Level of evidence

III, retrospective comparative study.

Editorial Commentary: Stump Sparing or Footprint Exposing? Management of the Tibial Remnant During Posterior Cruciate Ligament Reconstruction

Surgical management of an isolated grade III posterior cruciate ligament tear has been enveloped in debate since the first reconstruction technique report was written by Hey Groves in 1919. With the evolution of arthroscopy, party lines have been drawn over tibial inlay versus transtibial techniques, as well as single- versus double-bundle techniques. More subtle controversy exists regarding autograft versus allograft, outside-in versus inside-out drilling, and treatment of the tibial footprint of the posterior cruciate ligament. New remnant-sparing techniques, using a trans-septal posterior portal, may augment biology, maintain better proprioception, and mitigate abrasive wear at the "killer turn." However, longer-term comparative studies will be necessary to determine the existence of any clinically significant improvement in outcome.

Return to Sports and Clinical Outcomes After Arthroscopic Anatomic Posterior Cruciate Ligament Reconstruction With Remnant Preservation

PURPOSE

To evaluate the clinical outcomes of transtibial posterior cruciate ligament reconstruction (PCLR) with remnant preservation in highly active patients and to investigate the rate of return to sports (RTS), quality of sports activities, and patient satisfaction.

METHODS

Patients with a Tegner activity scale of >5 who underwent isolated PCLR from 2013 to 2016 with minimum 2-year follow-up were retrospectively reviewed. Single-bundle PCLR was performed using fresh frozen allograft irradiated with 50 kGy. Subjective assessments included the Lysholm score, subjective International Knee Documentation Committee score, and Tegner activity scale. A questionnaire elicited information associated with RTS and satisfaction. Functional tests included isokinetic muscle strength and single-leg hop tests.

RESULTS

We evaluated 52 patients, with a mean (± standard deviation) follow-up duration of 29.5 ± 8.6 months. The subjective assessments and functional tests significantly improved postoperatively (all P < .001). Mean time to return to full sports activity was 9.7 ± 5.1 months. Thirty-eight (73.1%) and 45 (86.5%) patients could return to previous sports activities at 9 and 24 months, respectively. A sports-experience questionnaire indicated that 48% and 69.2% of the patients were participating with unlimited effort and performance, respectively, and no pain at 9 and 24 months. Multivariate analysis indicated that extensor deficit (odds ratio [OR] 4.2, 95% confidence interval [CI] 1.342 to 17.839), flexor deficit at 60°/s (OR 3.8, 95% CI 1.081 to 14.476), Limb Symmetry Index (%) for the single-leg vertical jump test (OR 2.2, 95% CI 1.212 to 9.227), and satisfaction (OR 2.8, 95% CI 1.186 to 10.281) were significantly associated with failure of not returning to preinjury sports activity levels at the 9-month follow-up.

CONCLUSIONS

Arthroscopic anatomic PCLR with remnant preservation showed high rates of RTS and high patient satisfaction, as well as satisfactory clinical results in highly active patients. This surgical technique could be an effective treatment for grade III posterior cruciate ligament injury in highly active patients.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Graft Considerations in Posterior Cruciate Ligament Reconstruction

PURPOSE OF REVIEW

To highlight current and established concepts regarding PCL injury and reconstruction.

RECENT FINDINGS

Recent biomechanical and clinical studies have brought attention to improved surgical techniques and clinical outcomes of PCL reconstruction. In contrast to anterior cruciate ligament (ACL) injuries, isolated posterior cruciate ligament (PCL) injuries occur much less frequently and have traditionally been treated non-operatively. Even when a PCL injury meets operative indications, outcomes of PCL reconstruction historically do not match the success rates of ACL reconstruction procedures. As such, there remains controversy regarding appropriate indications and techniques for surgical repair leading to a paucity of conclusive data regarding surgical outcomes. Recently, however, there has been an increase in focus on the role of the PCL in proper knee biomechanics and negative long-term sequelae of chronic PCL insufficiency. This improved understanding has led to advancements in surgical technique and graft options for PCL reconstruction.

Open Tibial Inlay PCL Reconstruction: Surgical Technique and Clinical Outcomes

PURPOSE OF REVIEW

To review the current literature on clinical outcomes following open tibial inlay posterior cruciate ligament (PCL) reconstruction and provide the reader with a detailed description of the author's preferred surgical technique.

RECENT FINDINGS

Despite earlier biomechanical studies which demonstrated superiority of the PCL inlay technique when compared to transtibial techniques, recent longitudinal cohort studies have shown no significant differences in clinical or functional outcomes at 10-year follow-up. Furthermore, no significant clinical differences have been shown between graft types used and/or single- versus double-bundle reconstruction methods. The optimal treatment for the PCL-deficient knee remains unclear. Open tibial inlay PCL reconstruction is safe, reproducible, and avoids the "killer turn" that may potentially lead to graft weakening and failure seen in transtibial reconstruction methods. No significant differences in subjective outcomes or clinical laxity have been shown between single-bundle versus double-bundle reconstruction methods.

Revision PCL Reconstruction Review/Update

PURPOSE OF REVIEW

The primary goal of this review is to update recent literature on revision PCL reconstruction and to discuss factors relevant to surgical failure, surgical indications and goals, patient evaluation, surgical decision-making, graft selection, surgical technique, associated surgical procedures, postoperative rehabilitation, and revision PCL reconstruction results.

RECENT FINDINGS

Specifically, it is paramount to consider and treat posteromedial and posterolateral instability. Success in revision surgery focuses on appropriate graft choice and precise tunnel placement at anatomical attachment sites. Furthermore, correct tensioning of the graft, secondary or backup fixation and well-designed PT and rehab protocols are integral components. The factors causing failure of the primary reconstruction should be identified, as revision surgery must address the errors and follow strict surgical principals to be successful. There are many variables that play a role in successful revision posterior cruciate ligament (PCL) reconstruction. In general, as in most ligament reconstruction surgery, it is important to identify and address all associated pathology such as lower extremity malalignment and additional instability.

Arthroscopic Transtibial PCL Reconstruction: Surgical Technique and Clinical Outcomes

PURPOSE OF REVIEW

Posterior cruciate ligament (PCL) injuries are relatively uncommon injuries. As such, there is a dearth of high-quality studies in the literature examining the operative management of PCL injuries and a lack of clear consensus on what the optimal method should be. The goal of this review was to conduct a comprehensive evaluation of recent literature and provide an evidence-based algorithm to optimize surgical decision-making and outcomes for PCL reconstruction.

RECENT FINDINGS

Recent literature confirms that transtibial PCL reconstruction is a reliable and reproducible method to manage PCL injuries and results in satisfactory patient outcomes. However, there does not yet appear to be enough new, compelling information to conclusively determine an optimal method for surgical management. Our preferred method of management for operative PCL injuries is a single bundle transtibial PCL reconstruction, which is supported by the current body of literature. Future high-quality research studies are necessary to further guide treatment algorithms.

Posterior Cruciate Ligament: Current Concepts Review

The posterior cruciate ligament (PCL) is the largest and strongest ligament in the human knee, and the primary posterior stabilizer. Recent anatomy and biomechanical studies have provided an improved understanding of PCL function. PCL injuries are typically combined with other ligamentous, meniscal and chondral injuries. Stress radiography has become an important and validated objective measure in surgical decision making and post-operative assessment. Isolated grade I or II PCL injuries can usually be treated non-operatively. However, when acute grade III PCL ruptures occur together with other ligamentous injury and/or repairable meniscal body/root tears, surgery is indicated. Anatomic single-bundle PCL reconstruction (SB-PCLR) typically restores the larger anterolateral bundle (ALB) and represents the most commonly performed procedure. Unfortunately, residual posterior and rotational tibial instability after SB-PCLR has led to the development of an anatomic double-bundle (DB) PCLR to restore the native PCL footprint and co-dominant behavior of the anterolateral and posteromedial bundles and re-establish normal knee kinematics. The purpose of this article is to review the pertinent details regarding PCL anatomy, biomechanics, injury diagnosis and treatment options, with a focus on arthroscopically assisted DB-PCLR. Level of evidence: IV.