Steep lateral tibial slope and lateral-to-medial slope asymmetry are risk factors for concomitant posterolateral meniscus root tears in anterior cruciate ligament injuries

Increased Posterior Tibial Slope Is Associated With Increased Risk of Meniscal Root Tears: A Systematic Review

BACKGROUND

While increased posterior tibial slope (PTS) is an established risk factor for anterior cruciate ligament tears, the association between tibial slope and meniscal posterior root tears is not well-defined.

PURPOSE

To summarize the available literature evaluating the association between PTS and meniscus root injuries compared with patients without root tears.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A literature search was performed using the Scopus, PubMed, and Embase databases. Human clinical studies evaluating the associations between the medial tibial slope (MTS), lateral tibial slope (LTS), lateral-to-medial (L-to-M) slope asymmetry, and the risk of meniscus root tears were included. Patients with medial meniscus posterior root tears (MMPRTs) and lateral meniscus posterior root tears (LMPRTs) were compared with a control group without root injury. Study quality was assessed using the methodological index for non-randomized studies criteria.

RESULTS

Ten studies with 1313 patients were included (884 patients with root tears; 429 controls). The LMPRT subgroup (n = 284) had a significantly greater LTS (mean ± SD, 7.3°± 1.5° vs 5.7°± 3.91°; P < .001), MTS (5.26°± 1.2° vs 4.8°± 1.25°; P < .001), and increased L-to-M asymmetry (2.3°± 1.3° vs 0.65°± 0.5°; P < .001) compared with controls. The MMPRT group (n = 600) had significantly increased MTS relative to controls (8.1°± 2.5° vs 4.3°± 0.7°; P < .001). Furthermore, there was a higher incidence of noncontact injuries (79.3%) and concomitant ramp lesions (56%) reported in patients with LMPRT.

CONCLUSION

Increased MTS, LTS, and L-to-M slope asymmetry are associated with an increased risk of LMPRTs, while increased MTS is associated with MMPRTs. Surgeons should consider how proximal tibial anatomy increases the risk of meniscus root injury.

The increased lateral tibial slope may result in inferior long-term clinical outcome after DB-ACL reconstruction

PURPOSE

To determine if there is a correlation between lateral tibial slope and long-term clinical results in patients who underwent double-bundle ACL reconstruction.

METHODS

We retrospectively reviewed patients that received double-bundle ACL reconstruction at a single institution by a single surgeon from January 2011 to December 2014. All the magnetic resonance imaging were reviewed and lateral tibial slopes (LTS) were recorded by an experienced surgeon and rechecked by the other two authors of this study that specialized in orthopedic knee surgery. The relationship between PROMs measurement and lateral tibial slope were analyzed. The patients were then separated into two groups (LTS > 7.4° and < 7.4°) according to the previous study.

RESULTS

A total of 119 patients were enrolled in this study. All enrolled patients were followed for at least 8 years. The PROMS result were negatively correlated with the lateral tibial slope (p values all < 0.001). The patients with high lateral tibial slope had significantly lower PROMS values (Lysholm 94.26 ± 5.61 vs 80.15 ± 8.28, p = 0.013; IKDC 82.99 ± 4.55 vs 70.09 ± 7.15, p = 0.003; Tegner 9.32 ± 0.95 vs 6.85 ± 1.99, p < 0.001). Finally, the LTS cutoff value between patients with "Good" and "Fair" Lysholm score in our study was 7.55 degrees.

CONCLUSIONS

Patients with high lateral tibial slope may result in inferior long-term subjective outcomes. The using of double-bundle ACL reconstruction along cannot overcome the negative impact caused by steep lateral tibial slope. A lateral tibial slope of 7.55° may be used as a cut-off for a good clinical outcome.

LEVEL OF EVIDENCE

III retrospective comparative prognostic trial.

Does posterior tibial slope laterality exist? A matched cohort study between ACL-injured and non-injured knees

PURPOSE

The purpose of this study is to examine 1) the degree and frequency of laterality in posterior tibial slope (PTS) with control and anterior cruciate ligament (ACL) injury groups and 2) the laterality of PTS between sides of injury and dominant legs in patients with primary ACL injuries.

METHODS

A total of 187 consecutive patients with clinically diagnosed noncontact ACL injuries and an age- and sex-matched 1:1 control group were identified. PTS was measured using three different methods (aPTS = anterior PTS, mPTS = middle PTS, pPTS = posterior PTS) on a lateral knee radiograph. PTS of the left and right sides were compared between the patients in the control and ACL-injured groups, and between the injured and non-injured and dominant and non-dominant legs among the patients in the ACL-injured group. The patients with a difference in PTS of ≥ 3° in mPTS were selected. The percentages were compared between left and right between and among both groups, and between the injured and non-injured, and non-dominant and dominant leg, for the ACL group. Multiple regression analysis was performed to analyze the factors influencing the degree of mPTS.

RESULTS

Both control (Right vs Left: aPTS; 9.0 ± 2.5 vs 10.5 ± 3.0, mPTS; 6.6 ± 2.3 vs 8.1 ± 2.7, pPTS; 4.0 ± 2.4 vs 5.6 ± 2.8, respectively, p < 0.01) and ACL injury groups (Right vs Left: aPTS; 10.6 ± 3.0 vs 12.6 ± 2.9, mPTS; 7.6 ± 2.6 vs 9.5 ± 2.6, pPTS; 5.9 ± 3.0 vs 8.0 ± 3.0, respectively, p < 0.01) had a significantly greater PTS on the left than on the right side, and the ACL group had a significantly greater PTS than the control group on both the left and right sides. In the ACL group, PTS was greater on the injured and the non-dominant leg than on the non-injured and the dominant leg. The percentage of patients with a PTS difference of ≥ 3° was significantly greater on the left, injured, and non-dominant leg (95.3% vs 4.7%, 73.8% vs 26.2%, 86.1% vs 13.9%, respectively, p < 0.01). Only the left leg had a significant influence on PTS in the multivariate analysis.

CONCLUSION

There was laterality in PTS within control and ACL injury groups, and this information is of benefit for effective treatment of ACL injuries.

LEVEL OF EVIDENCE

Level III.

Comparison of Size of Posterior Tibial Slope and Medial Tibial Depth in Patients With an Isolated Meniscal Tear Requiring Surgery and Matched Uninjured Controls

BACKGROUND

Meniscal injuries are extremely common. Several anatomic features of the knee, including the tibial plateau morphology, have been shown to influence knee biomechanics and the risk of ligamentous injuries. Little is known, however, how these morphological features influence the risk of isolated meniscal injuries in the anterior cruciate ligament (ACL)-intact knee.

HYPOTHESIS

There are differences in the slopes and concavity of the tibial plateau between patients with isolated meniscal tears and matched uninjured controls.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

In total, 89 patients with first-instance isolated medial (n = 37) or lateral (n = 52) meniscal injuries requiring surgical treatment (mean age, 16 ± 1 years; 35% female) were matched to 89 controls with uninjured knees and no previous injuries (mean age, 16 ± 2 years; 35% female) based on age and sex. Magnetic resonance imaging scans (preoperative for injured group) were used to measure the coronal slope of the tibial plateau, posterior slope of the medial and lateral tibial plateaus, and maximum depth of the medial tibial plateau. General linear models were used to evaluate the differences in tibial plateau morphology between the knees with and without meniscal injuries, with and without adjustment for age and sex.

RESULTS

Compared with matched controls, patients with surgically treated isolated meniscal tears had a smaller lateral tibial slope (by 2.2° [medial meniscal injury] and 1.6° [lateral meniscal injury]; P < .02), a smaller medial tibial slope (by 2.3° [medial meniscal injury] and 2.4° [lateral meniscal injury]; P < .001) and a larger medial tibial depth (by 0.8 mm [medial meniscal injury] and 0.9 mm [lateral meniscal injury]; P < .001). There were no differences in coronal tibial slope between the injured and uninjured groups. There were no differences in quantified anatomic features between the isolated medial and lateral meniscal injury groups. The same trends were observed after adjusting for age and sex.

CONCLUSION

This study suggests that patients with an isolated meniscal tear requiring surgery have a smaller posterior tibial slope and a larger medial tibial depth (more concave medial tibial plateau) than matched uninjured controls. This is contrary to what is known for ACL tears, in which a steeper posterior tibial slope and a shallower medial tibial depth have been associated with an increased risk of ACL tear.

Outcomes of Slope-Reducing Proximal Tibial Osteotomy Combined With a Third Anterior Cruciate Ligament Reconstruction Procedure With a Focus on Return to Impact Sports

BACKGROUND

An increased posterior tibial slope (PTS) is a proven risk factor for both native anterior cruciate ligament (ACL) and ACL graft insufficiency. Anterior closing wedge high tibial osteotomy (ACW-HTO) for PTS correction is a validated procedure in revision ACL reconstruction (ACLR).

PURPOSE/HYPOTHESIS

The aim of this study was to evaluate the effect of combined ACW-HTO and at least a second revision ACLR procedure on knee stability, function, and sports performance in a large series of patients. The hypothesis was that patients would return to impact sports after ACW-HTO combined with a second or third revision ACLR procedure.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 64 patients who underwent a second (or more) revision ACLR procedure and ACW-HTO between June 1, 2015, and June 1, 2019, and had a PTS >12° were included. The mean age was 29.60 ± 6.31 years, and the mean preoperative PTS was 13.79°± 1.50°. The cases were analyzed at a mean follow-up of 2.96 ± 0.83 years (range, 2-5 years). At the last follow-up, the rate of patients returning to impact sports (based on the University of California, Los Angeles [UCLA], activity scale), ACL graft status (per magnetic resonance imaging), International Knee Documentation Committee (IKDC) scores, Lysholm scores, and laxity measurements using a knee arthrometer were recorded.

RESULTS

The total number of patients participating in impact sports and high-impact sports was as follows: 43 and 30, respectively, before the injury; 0 and 0, respectively, preoperatively; and 31 and 12, respectively, postoperatively. At the last follow-up, the UCLA score was ≥8 in 48.44% of the patients, and only 16 patients returned to their preinjury level of activity. At a minimum of 2 years of follow-up, there was clinical improvement in the IKDC score from 37.98 ± 12.48 preoperatively to 69.06 ± 12.30 postoperatively (P < .0001), in the Lysholm score from 51.94 ± 14.03 preoperatively to 74.45 ± 11.44 postoperatively (P < .001), and in the UCLA score. However, this clinical improvement did not equate to preinjury values for all outcome scores (P < .001). The preinjury IKDC and Lysholm scores were 76.98 ± 11.71 and 89.26 ± 8.91, respectively. The mean change in anterior knee laxity using a knee arthrometer at 134 and 250 N was -4.03 ± 0.18 mm and -3.63 ± 0.16, respectively. There were 3 cases of a rerupture with a severe pivot shift on the clinical examination. None of these patients underwent revision per the patient's preference. Increased knee recurvatum was observed in one-third of the patients, but all were asymptomatic.

CONCLUSION

In the setting of chronic ACL-deficient knees, PTS reduction (ACW-HTO) with revision ACLR restored knee stability and improved function with an acceptable rate of specific complications. Increased knee recurvatum was observed in one-third of the patients, but all were asymptomatic. Also, approximately half of the patients were able to return to impact sports.

Lateral-medial asymmetry of posterior tibial slope and small lateral tibial plateau articular surface depth are morphological factors of lateral meniscus posterior root tears in ACL-injured patients

PURPOSE

To investigate whether knee morphological features, patient characteristics, and intraoperative findings are associated with a lateral meniscus (LM) posterior root tear (LMPRT) in anterior cruciate ligament (ACL) injuries with the integrated data from two academic centres.

METHODS

This retrospective study used registry data acquired prospectively at two academic centres. Patients with ACL reconstruction (ACLR) with LMPRT and no other LM injury were selected (LMPRT group) from each database. The control group included patients who underwent ACLR without LM tears. Patients were matched to the LMPRT group according to age and gender (1:1). Morphological factors evaluated on preoperative magnetic resonance image scans included lateral femoral condyle (LFC) anterior-posterior diameter, height, and depth; lateral tibial plateau (LTP) articular surface (AS) depth and sagittal plane depth; and lateral and medial posterior tibial slopes (PTSs). LFC height and depth ratios, LTP AS depth and sagittal plane depth ratios, and lateral-to-medial slope asymmetry were computed from previous measurements. Patient characteristics and intraoperative findings were extracted and compared between both groups.

RESULTS

The study included 252 patients (126 in each group). The lateral-medial asymmetry of PTS was greater in the LMPRT group (1.2° vs 0.3°, p < 0.05), and the LTP AS depth was smaller in the LMPRT group (31.4 mm vs 33.2 mm, p < 0.01). There were no differences in LFC morphology between the control and LMPRT groups. Pivot shift grade (p < 0.05), percentage of complete ACL tears (p < 0.05), and medial meniscus ramp lesions (p < 0.05) were significantly higher in the LMPRT group.

CONCLUSION

LMPRT was associated with significantly increased lateral-medial asymmetry of PTS and significantly smaller LTP AS depth. LMPRT was also associated with an increase in the preoperative pivot shift grade and the presence of a medial meniscus ramp lesion. These morphological characteristics are rather simple to measure and would serve as helpful indicators to preoperatively detect LMPRT, which is frequently challenging to diagnose preoperatively.

LEVEL OF EVIDENCE

Level III.

Risk Factors for Concomitant Meniscal Injury With Sport-Related Anterior Cruciate Ligament Injury

Background

Previous studies of concomitant meniscal injury in athletes with anterior cruciate ligament (ACL) injury have examined age, sex, body mass index (BMI), injury mechanism, and time from injury to surgery as potential risk factors.

Purpose

To identify additional risk factors for concomitant meniscal injury, including preinjury joint laxity and lower extremity alignment, in athletes with sport-related ACL injury.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

This study included 180 participants aged 13 to 26 years who underwent ACL reconstruction (ACLR) after a first-time ACL injury sustained during participation in sport. Contralateral lower extremity alignment and joint laxity were used as surrogate measures for the injured knee before trauma. Concomitant meniscal tear patterns were identified at the time of ACLR. Sex-specific analyses were conducted.

Results

Concomitant meniscal injury was observed in 60.6% of the subjects. The prevalence of concomitant injury was higher in male than female participants (69.9% vs 54.2%; P = .035) due to a higher prevalence of lateral meniscal injuries (56.2% vs 38.3%; P = .018). Among male patients, there was a significant difference in the prevalence of concomitant lateral meniscal tear according to sport participation (≥9 vs <9 h/week: 67.4% vs 35.7%; P = .032). Among male patients, the likelihood of concomitant injury to both the lateral and medial menisci increased by 28.8% for each 1-mm decrease in navicular drop. Among female patients, the likelihood of concomitant injury to the lateral meniscus increased by 15% per degree increase in genu recurvatum and 14% per degree decrease in standing quadriceps angle, with similar effects on the likelihood of concurrent injury to both the lateral and medial menisci.

Conclusion

Measures of lower extremity alignment and genu recurvatum previously identified as risk factors for ACL injury were also associated with concomitant meniscal injury in female patients while other risk factors, including BMI and joint laxity, were not. Increased time spent participating in sport and navicular drop were associated with concomitant meniscal injury in male patients.

Extent of posterolateral tibial plateau impaction fracture correlates with anterolateral complex injury and has an impact on functional outcome after ACL reconstruction

PURPOSE

The impact of posterolateral tibial plateau impaction fractures (TPIF) on posttraumatic knee stability in the setting of primary anterior cruciate ligament (ACL) tear is unknown. The main objective was to determine whether increased bone loss of the posterolateral tibial plateau is associated with residual rotational instability and impaired functional outcome after ACL reconstruction.

METHODS

A cohort was identified in a prospective enrolled study of patients suffering acute ACL injury who underwent preoperative standard radiographic diagnostics and clinical evaluation. Patients were included when scheduled for isolated single-bundle hamstring autograft ACL reconstruction. Exclusion criteria were concurrent anterolateral complex (ALC) reconstruction (anterolateral tenodesis), previous surgery or symptoms in the affected knee, partial ACL tear, multi-ligament injury with an indication for additional surgical intervention, and extensive cartilage wear. On MRI, bony (TPIF, tibial plateau, and femoral condyle morphology) and ligament status (ALC, concomitant collateral ligament, and meniscus injuries) were assessed by a musculoskeletal radiologist. Clinical evaluation consisted of KT-1000, pivot-shift, and Lachman testing, as well as Tegner activity and IKDC scores.

RESULTS

Fifty-eight patients were included with a minimum follow-up of 12 months. TPIF was identified in 85% of ACL injuries (n = 49). The ALC was found to be injured in 31 of 58 (53.4%) cases. Pearson analysis showed a positive correlation between TPIF and the degree of concomitant ALC injury (p < 0.001). Multiple regression analysis revealed an increased association of high-grade TPIF with increased lateral tibial convexity (p = 0.010). The high-grade TPIF group showed worse postoperative Tegner scores 12 months postoperatively (p = 0.035).

CONCLUSION

Higher degrees of TPIFs are suggestive of a combined ACL/ALC injury. Moreover, patients with increased posterolateral tibial plateau bone loss showed lower Tegner activity scores 12 months after ACL reconstruction.

LEVEL OF EVIDENCE

III.

Steeper lateral posterior tibial slope and greater lateral-medial slope asymmetry correlate with greater preoperative pivot-shift in anterior cruciate ligament injury

PURPOSE

To investigate the association between posterior tibial slope (PTS) and preoperative pivot-shift phenomenon in anterior cruciate ligament (ACL)-injured knees.

METHODS

Fifty unilateral ACL-injured patients (mean age: 28.0 ± 11.4 years, 29 males) who underwent ACL reconstruction were retrospectively included. Patients with a history of injury to the ipsilateral knee joint, concomitant ligament injuries with ACL injury, and/or more than one year from injury to surgery, were excluded. Pivot-shift tests were performed preoperatively under general anaesthesia using an electromagnetic measurement system, and tibial acceleration (m/s²) during the posterior reduction of the tibia was measured. Medial and lateral PTS (°) were measured respectively using high-resolution CT images taken two weeks after surgery. Lateral-medial slope asymmetry was calculated by subtracting medial PTS from lateral PTS (lateral-medial PTS) and we evaluated the correlation between each PTS parameter (medial PTS, lateral PTS, and lateral-medial slope asymmetry) and tibial acceleration during the pivot-shift test. The level of significance was set at p < 0.05.

RESULTS

Medial PTS was 4.9 ± 2.0°, and lateral PTS was 5.2 ± 1.9°. The lateral-medial slope asymmetry was 0.3 ± 1.6° (range: -2.9 to 3.8). Tibial acceleration during the pivot-shift test in the ACL-injured knee was 1.6 ± 0.1 m/s². Preoperative tibial acceleration was positively correlated with lateral PTS (r = 0.436, p < 0.01), and lateral-medial slope asymmetry (r = 0.443, p < 0.01), while no significant correlation was found between preoperative tibial acceleration and medial PTS (r = 0.06, p = 0.70).

CONCLUSION

Preoperative greater tibial acceleration during the pivot-shift test was associated with steeper lateral PTS and greater lateral-medial slope asymmetry in ACL-injured knees. These findings improve our understanding of anterolateral rotatory knee laxity by linking tibial bony morphology to quantitative measurement of pivot-shift phenomenon. Surgeons should be aware that not only lateral PTS but also lateral-medial slope asymmetry are the factors associated with preoperative pivot-shift.

LEVEL OF EVIDENCE

Level IV.

Tibial slope in the posterolateral quadrant with and without ACL injury

INTRODUCTION

An increased tibial slope is a risk factor for rupture of the anterior cruciate ligament. In addition, a tibial bone bruise or posterior lateral impression associated with slope changes also poses chronic ligamentous instability of the knee joint associated with an anterior cruciate ligament (ACL) injury. In the majority of cases, the slope is measured in one plane X-ray in the lateral view. However, this does not sufficient represent the complex anatomy of the tibial plateau and especially for the posterolateral quadrant. Normal values from a "healthy" population are necessary to understand if stability of the knee joint is negatively affected by an increasing slope in the posterolateral area. Until now there are no data about the physiological slope in the posterolateral quadrant of the tibial plateau.

MATERIALS AND METHODS

In 116 MRI scans of patients without ligamentous lesions and 116 MRI scans with an ACL rupture, tibial slope was retrospectively determined using the method described by Hudek et al. Measurements were made in the postero-latero-lateral (PLL) and postero-latero-central (PLC) segments using the 10-segment classification. In both segments, the osseous as well as the cartilaginous slope was measured. Measurements were performed by two independent surgeons.

RESULTS

In the group without ligamentous injury the mean bony PLL slope was 5.8° ± 4.8° and the cartilaginous PLL slope was 6.7° ± 4.8°. In the PLC segment the mean bony slope was 6.6° ± 5.0° and the cartilaginous slope was 9.4° ± 5.7°. In the cohort with ACL rupture, the bony and cartilaginous slope in both PLL and PCL were significantly higher (P < 0.001) than in the group without ACL injury (bony PLL 9.8° ± 4.8°, cartilage PLL 10.4° ± 4.7°, bony PLC 10.3° ± 4.8°, cartilage PLL 12.8° ± 4.3°). Measurements were performed independently by two experienced surgeons. There were good inter- (CI 87-98.7%) and good intraobserver (CI 85.8-99.6%) reliability.

CONCLUSION

The bony and the cartilaginous slope in the posterolateral quadrant of the tibial plateau are different but not independent. Patients with an anterior cruciate ligament injury have a significantly steeper slope in the posterolateral quadrant compared to a healthy group. Our data indicate that this anatomic feature might be a risk factor for a primary ACL injury which has not been described yet.

LEVEL OF EVIDENCE

III.

Age, male sex, higher posterior tibial slope, deep sulcus sign, bone bruises on the lateral femoral condyle, and concomitant medial meniscal tears are risk factors for lateral meniscal posterior root tears: a systematic review and meta-analysis

PURPOSE

Lateral meniscus posterior root tears (LMPRTs) are commonly found in patients with anterior cruciate ligament (ACL) injuries. However, risk factors for LMPRTs are not well known. This study was designed to systematically review the available evidence regarding risk factors associated with LMPRTs.

METHODS

The PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched for papers containing the key words "lateral meniscus posterior root tears", "LMPRTs" and "risk factor". Inclusion screening, data extraction, and quality assessment of the included articles were conducted independently by two authors. Statistical analysis was conducted to determine risk factors for LMPRTs.

RESULT

Seventeen studies with a total sample size of 6, 589 patients were identified. The pooled prevalence of LMPRTs was 9.6% (range, 5.1-33.8%) for ACL injury. Significant risk factors included a patient age of < 30 [OR = 1.4, 95% CI (1.07, 1.84), p = 0.01], male sex [OR = 1.50, 95% CI (1.24,1.81), p = 0.01], higher body mass index (BMI) [MD = 0.45, 95% CI (0.13, 0.76), p < 0.01], higher lateral posterior tibial slope (LPTS) [MD = 2.22, 95% CI (1.37, 3.07), p < 0.01], deep sulcus sign [OR = 5.76, 95% CI (1.35, 24.52), p < 0.01] and bone bruises on lateral femoral condyle [OR = 4.88, 95% CI (1.27, 18.77), p < 0.01], lateral meniscal extrusion > 1 mm [OR = 5.56, 95% CI (1.52, 20.29), p < 0.01] and > 3 mm [OR = 12.91 95% CI (1.28, 130.01), p < 0.01], medial meniscal tears [OR = 1.40, 95% CI (1.12, 1.75), p < 0.01], and medial ramp lesions [OR = 2.29, 95% CI (1.35, 3.89), p < 0.01].

CONCLUSION

Age below 30, male, higher BMI, higher LPTS, deep sulcus sign, bone bruises on lateral femoral condyle, lateral meniscal extrusion, medial meniscal tear, and medial ramp lesion are risk factors for LMPRTs.

LEVEL OF EVIDENCE

Level IV.

Ipsilateral ACL injured patients with Segond fractures demonstrate increased posterior tibial slope

BACKGROUND

The anterolateral complex has been demonstrated to assist with rotational stability and prevention of anterior tibial translation during the pivot shift. In this study the Segond fracture is used as a surrogate for an anterolateral complex injury to determine if there is an association between Segond fracture and increased posterior tibial slope.

METHODS

Patients' charts and radiographs were analyzed retrospectively for the presence of Segond fractures on injury radiographs. These patients, the Segond cohort, were then age and gender matched to a control cohort. Demographic as well MRI measurements of medial and lateral posterior tibial slope and lateral-to-medial slope asymmetry were collected for each cohort. Secondary outcome of anterior cruciate ligament reconstruction failure data was also collected.

RESULTS

The Segond group demonstrated a statistically significantly greater lateral posterior tibial slope (8.42° versus 6.55°, P = 0.003) as well as medial posterior tibial slope (6.57° versus 5.34° degrees, P = 0.045). There was no significant differences between lateral-to-medial asymmetry (2.18°versus 1.83°, P = 0.246).

CONCLUSION

Patients with Segond fractures at the time of anterior cruciate ligament injury have increased medial and lateral posterior tibial slope. This may relate to increased rotational and translational instability associated with anterolateral complex injuries. Surgeons treating these patient may use this information to counsel their patients on the risks of associated pathology at the time of arthroscopy such as lateral meniscal posterior root tears.

Increased Posterior Tibial Slope and Meniscal Slope Could Be Risk Factors for Meniscal Injuries: A Systematic Review

PURPOSE

The purpose of this systematic review was to summarize the available evidence and examine the relation between the posterior tibial slope (PTS) and meniscal slope (MS) and the incidence of meniscal injury.

METHODS

PubMed, Embase, the Cochrane Central Register of Controlled Trials, and Web of Science were searched from inception to February 23, 2021. Cohort studies investigating the association between PTS or MS and the risk of meniscal injury were included. Two authors independently conducted the literature search, data extraction, and quality assessment.

RESULTS

Sixteen studies with a total of 2,670 patients were included. For meniscal injury with an anterior cruciate ligament tear, the lateral PTS in the lateral meniscal root tear group (range, 8.0°-12.6°) was significantly higher than that in the control group (range, 4.0°-10.7°). Furthermore, there appeared to be a relation between a greater medial MS and the presence of a ramp lesion (range, 2.6°-6.7° for ramp lesion vs 2.0°-5.1° for control). For degenerative meniscal injury, the medial PTS in the medial meniscal posterior root tear group (range, 6.15°-10.4°) was significantly greater than that in the control group (range, 4.0°-9.8°).

CONCLUSIONS

On the basis of the available evidence, for meniscal injury with an anterior cruciate ligament tear, an increased lateral PTS was associated with a higher risk of lateral meniscal tears and lateral meniscal posterior root tears. Furthermore, there appeared to be a relation between an increased medial MS and a higher risk of ramp lesions. For degenerative meniscal injury, most of the included studies showed that a larger medial PTS could increase the risk of medial meniscal tears and medial meniscal posterior root tears.

LEVEL OF EVIDENCE

Level III, systematic review of Level III studies.

Posterior Tibial Slope in Patients With Torn ACL Reconstruction Grafts Compared With Primary Tear or Native ACL: A Systematic Review and Meta-analysis

Background:

Increased posterior tibial slope (PTS) is a risk factor for anterior cruciate ligament (ACL) rupture and failure of ACL reconstruction (ACLR) grafts.

Purpose:

The purpose was to conduct a systematic review of literature on PTS measurements and to conduct a meta-analysis of comparable PTS measurements based on a patient’s ACL status. It was hypothesized that patients with torn ACLR grafts would have significantly larger medial and lateral PTS compared with patients with native ACLs or those who underwent primary ACLR.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review was performed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included were studies that reported medial and/or lateral PTS measurements, those that reported PTS measurements based on ACL status (ie, intact ACL, primary ACL tear, failed ipsilateral ACLR, or revision ACLR), and those that reported their specific PTS measurement technique. Average PTS measurements, measurement location (medial or lateral tibial plateau) and technique, imaging modality used, and ACL status were extracted from each study. Data were pooled using DerSimonian and Laird random-effects models, and results were compared using the Altman interaction test.

Results:

The literature search identified 1705 studies, of which 82 (N = 12,971 patients) were included. There were 4028 patients in the intact ACL group (31%), 7405 in the primary ACLR group (57%), and 1538 in the failed ACLR group (12%). Measurements were obtained from lateral radiographs in 31 studies (38%), from magnetic resonance imaging in 47 studies (57%), and from computed tomography in 4 studies (5%). The failed ACLR group had a significantly larger lateral PTS (9.55°; 95% CI, 8.47°-10.63°) than either the primary ACL tear (7.13°; 95% CI, 6.58°-7.67°) or intact ACL (5.57°; 95% CI, 5.03°-6.11°) groups (P < .001 for both). The failed ACLR group also had a significantly larger medial PTS (9.05°; 95% CI, 7.80°-10.30°) than the primary (6.24°; 95% CI, 5.71°-6.78°) or intact ACL (6.28°; 95% CI, 5.21°-7.35°) groups (P < .001 for both).

Conclusion:

Both lateral and medial PTS measurements were greater in patients who had failed previous ACLR than those with a primary ACL tear or an intact native ACL. The lateral PTS of patients with primary ACL tears was greater than those with an intact native ACL.

Posterior tibial slope measurements based on the full-length tibial anatomic axis are significantly increased compared to those based on the half-length tibial anatomic axis

PURPOSE

This study aimed to compare the difference in posterior tibial slope (PTS) measurements based on the full-length and half-length tibial anatomic axes of the same group of patients. It was hypothesized that the obtained PTS values would be affected by the length of tibia chosen during the measurements.

METHODS

Full-length true lateral tibia radiographs were obtained for each patient who underwent anterior cruciate ligament reconstruction (ACLR) in our department. PTS measurements were obtained by measuring the angle between the full-length or half-length tibial anatomic axis and an average of the lateral and medial tibial plateau. The anatomic axis was defined as the center of the tibial diaphysis. The PTS measurements from the full-length and half-length true lateral tibia radiographs were obtained and compared. Additionally, the absolute difference and the relationship between the two PTS measurements were calculated and analyzed.

RESULTS

A total of 200 ACL-injured patients were included in this study. The average PTS values using the anatomic axis were 15.9 ± 3.7° and 14.1 ± 3.7° on full-length and half-length true lateral tibial radiographs. There was a significant difference between the measurements with the full-length and half-length tibial radiographs (P < 0.01). Additionally, 49.5% (n = 99) of patients had ≥ 2.0° differences between the full-length and half-length anatomic axis PTS measurement techniques; meanwhile, a strong and significant linear relationship (r = 0.95; P < 0.001) was identified between the two PTS measurements.

CONCLUSION

There were significant differences and linear relationships between PTS measurements that measured the anatomic axis from full-length and half-length true lateral tibia radiographs. Therefore, the obtained PTS values were strongly associated with the length of tibia chosen during the measurements. Surgeons should pay more attention to the measurement techniques and the tibial length when considering the role of PTS in ACL injury and ACLR failure. Knowledge of the association is very important for calculating potential closing wedge proximal tibial osteotomies to correct excessive PTS in the setting of ACLR failures.

LEVEL OF EVIDENCE

IV.

Large lateral tibial slope and lateral-to-medial slope difference are risk factors for poorer clinical outcomes after posterolateral meniscus root tear repair in anterior cruciate ligament reconstruction

BACKGROUND

Meniscus root tear is an uncommon but detrimental injury of the knee. Hoop stress is lost during meniscus root tear, which can lead to excessive tibiofemoral contact pressure and early development of osteoarthritis. Posterolateral meniscus root tears (PLRT) are more commonly associated with anterior cruciate ligament (ACL) tears. As the lateral compartment is less congruent than the medial compartment, it is more susceptible to a shearing force, which is increased in the ACL-deficient knee. In accordance with the compressive axial load, the increase in the tibial slope would generate a greater shearing force. The additional lateral compartment mobility caused by ACL tear should be reduced after ACL reconstruction (ACLR). However, there is a lack of evidence to conclude that ACLR can sufficiently limit the effect of large tibial slope (LTS) on the healing after PLRT repair. This study aimed to evaluate whether a steep LTS would be a risk factor for poorer clinical outcomes after PLRT repair concomitant with ACLR.

METHODS

In this retrospective study, a chart review was conducted to identify patients with concomitant unilateral primary ACLR and PLRT repair. Patients with a partial tear or healed tear were excluded. Postoperative MRI and clinical assessments were performed at a mean follow up of 35 months. MRI data was used to measure the LTS, medial tibial slope (MTS), coronal tibial slope (CTS), the lateral-to-medial slope difference (LTS-MTS) and meniscus healing and extrusion. Functional outcomes were evaluated by patient-reported outcomes (International Knee Documentation Committee [IKDC], Lysholm and Tegner scores) and KT-1000 arthrometer assessment. Interobserver reproducibility was assessed by two reviewers.

RESULTS

Twenty-five patients were identified for the analysis. Patients with larger LTS and larger LTS-MTS differences were shown to be correlated with poorer IKDC scores after surgery (R = -0.472, p = 0.017 and R = -0.429, p = 0.032, respectively). Herein, patients with LTS ≥ 6° or LTS-MTS ≥ 3° demonstrated poorer IKDC scores.

CONCLUSION

A large LTS (≥ 6°) and a large difference of LTS-MTS (≥ 3°) were shown to be risk factors for poorer functional and radiological outcomes for PLRT repair in patients after ACLR. Clinically, closer monitoring and a more stringent rehabilitation plan for patients with LTS ≥ 6° or LTS-MTS ≥ 3° would be recommended.

Steep posterior lateral tibial slope, bone contusion on lateral compartments and combined medial collateral ligament injury are associated with the increased risk of lateral meniscal tear

PURPOSE

To determine the risk factors for lateral meniscus and root tears in patients with acute anterior cruciate ligament (ACL) injuries.

METHODS

A total of 226 patients undergoing acute ACL reconstruction were included in the study sample. Exclusion criteria were revisions, fractures, chronic cases, and multiple ligament injuries, with the exception of medial collateral ligament (MCL) injuries. The patients were divided into groups based on the presence of lateral meniscus and root tears by arthroscopy. Binary logistic regression was used to analyze risk factors including age, sex, body mass index (BMI), injury mechanism (contact/non-contact), Segond fracture, side-to-side laxity, location of bone contusion, medial and lateral tibial and meniscal slope, mechanical axis angle, and grade of pivot shift.

RESULTS

Overall lateral meniscus (LM) tears were identified in 97 patients (42.9%), and LM root tears were found in 22 patients (9.7%). The risk of an LM tear in ACL-injured knees increased with bone contusion on LTP (odds ratio [OR], 3.5; 95% confidence interval [CI] 1.419-8.634; P = 0.007), steeper lateral tibial slope (OR, 1.133; 95% CI 1.003-1.28; P = 0.045), MCL injury (OR, 2.618; 95% CI 1.444-4.746; P = 0.002), and non-contact injury mechanism (OR, 3.132; 95% CI 1.446-6.785; P = 0.004) in logistic regression analysis. The risk of LM root tear in ACL-injured knees increased with high-grade pivot shift (OR, 9.127; 95% CI 2.821-29.525; P = 0.000) and steeper lateral tibial slope (OR, 1.293; 95% CI 1.061-1.576; P = 0.011).

CONCLUSION

The increased risk of LM lesions in acute ACL-injured knees should be considered if significant risk factors including bone contusion on lateral compartments, MCL injury, and a steeper lateral tibial slope are present. Moreover, high-grade rotational injury with steeper lateral tibial slope are also significant risk factors for LM root tears, and therefore care should be taken by clinicians not to miss such lesions.

LEVEL OF EVIDENCE

III.

High incidence of superficial and deep medial collateral ligament injuries in 'isolated' anterior cruciate ligament ruptures: a long overlooked injury

PURPOSE

In anterior cruciate ligament (ACL) injuries, concomitant damage to peripheral soft tissues is associated with increased rotatory instability of the knee. The purpose of this study was to investigate the incidence and patterns of medial collateral ligament complex injuries in patients with clinically 'isolated' ACL ruptures.

METHODS

Patients who underwent ACL reconstruction for complete 'presumed isolated' ACL rupture between 2015 and 2019 were retrospectively included in this study. Patient's characteristics and intraoperative findings were retrieved from clinical and surgical documentation. Preoperative MRIs were evaluated and the grade and location of injuries to the superficial MCL (sMCL), dMCL and the posterior oblique ligament (POL) recorded. All patients were clinically assessed under anaesthesia with standard ligament laxity tests.

RESULTS

Hundred patients with a mean age of 22.3 ± 4.9 years were included. The incidence of concomitant MCL complex injuries was 67%. sMCL injuries occurred in 62%, dMCL in 31% and POL in 11% with various injury patterns. A dMCL injury was significantly associated with MRI grade II sMCL injuries, medial meniscus 'ramp' lesions seen at surgery and bone oedema at the medial femoral condyle (MFC) adjacent to the dMCL attachment site (p < 0.01). Logistic regression analysis identified younger age (OR 1.2, p < 0.05), simultaneous sMCL injury (OR 6.75, p < 0.01) and the presence of bone oedema at the MFC adjacent to the dMCL attachment site (OR 5.54, p < 0.01) as predictive factors for a dMCL injury.

CONCLUSION

The incidence of combined ACL and medial ligament complex injuries is high. Lesions of the dMCL were associated with ramp lesions, MFC bone oedema close to the dMCL attachment, and sMCL injury. Missed AMRI is a risk factor for ACL graft failure from overload and, hence, oedema in the MCL (especially dMCL) demands careful assessment for AMRI, even in the knee lacking excess valgus laxity. This study provides information about specific MCL injury patterns including the dMCL in ACL ruptures and will allow surgeons to initiate individualised treatment.

LEVEL OF EVIDENCE

III.

Current trends in the anterior cruciate ligament part 1: biology and biomechanics

A trend within the orthopedic community is rejection of the belief that "one size fits all." Freddie Fu, among others, strived to individualize the treatment of anterior cruciate ligament (ACL) injuries based on the patient's anatomy. Further, during the last two decades, greater emphasis has been placed on improving the outcomes of ACL reconstruction (ACL-R). Accordingly, anatomic tunnel placement is paramount in preventing graft impingement and restoring knee kinematics. Additionally, identification and management of concomitant knee injuries help to re-establish knee kinematics and prevent lower outcomes and registry studies continue to determine which graft yields the best outcomes. The utilization of registry studies has provided several large-scale epidemiologic studies that have bolstered outcomes data, such as avoiding allografts in pediatric populations and incorporating extra-articular stabilizing procedures in younger athletes to prevent re-rupture. In describing the anatomic and biomechanical understanding of the ACL and the resulting improvements in terms of surgical reconstruction, the purpose of this article is to illustrate how basic science advancements have directly led to improvements in clinical outcomes for ACL-injured patients.Level of evidenceV.

Medial meniscal ramp lesions in ACL-injured elite athletes are strongly associated with medial collateral ligament injuries and medial tibial bone bruising on MRI

PURPOSE

Medial menisco-capsular separations (ramp lesions) are typically found in association with anterior cruciate ligament (ACL) deficiency. They are frequently missed preoperatively due to low MRI sensitivity. The purpose of this article was to describe demographic and anatomical risk factors for ramp lesions, and to identify concomitant lesions and define their characteristics to improve diagnosis of ramp lesions on MRI.

METHODS

Patients who underwent anterior cruciate ligament (ACL) reconstruction between September 2015 and April 2019 were included in this study. The presence/absence of ramp lesions was recorded in preoperative MRIs and at surgery. Patients' characteristics and clinical findings, concomitant injuries on MRI and the posterior tibial slope were evaluated.

RESULTS

One hundred patients (80 male, 20 female) with a mean age of 22.3 ± 4.9 years met the inclusion criteria. The incidence of ramp lesions diagnosed at surgery was 16%. Ramp lesions were strongly associated with injuries to the deep MCL (dMCL, p < 0.01), the superficial medial collateral ligament (sMCL, p < 0.01), and a small medial-lateral tibial slope asymmetry (p < 0.05). There was also good correlation between ramp lesions and bone oedema in the posterior medial tibia plateau (MTP, p < 0.05) and medial femoral condyle (MFC, p < 0.05). A dMCL injury, a smaller differential medial-lateral tibial slope than usual, and the identification of a ramp lesion on MRI increases the likelihood of finding a ramp lesion at surgery. MRI sensitivity was 62.5% and the specificity was 84.5%.

CONCLUSION

The presence on MRI of sMCL and/or dMCL lesions, bone oedema in the posterior MTP and MFC, and a smaller differential medial-lateral tibial slope than usual are highly associated with ramp lesions visible on MRI. Additionally, a dMCL injury, a flatter lateral tibial slope than usual, and the identification of a ramp lesion on MRI increases the likelihood of finding a ramp lesion at surgery. Knowledge of the risk factors and secondary injury signs associated with ramp lesions facilitate the diagnosis of a ramp lesion preoperatively and should raise surgeons' suspicion of this important lesion.

LEVEL OF EVIDENCE

Diagnostic study, Level III.

Measurement of Medial Tibial Eminence Dimensions for the Clinical Evaluation of ACL-Injured Knees: A Comparison between CT and MRI

Anterior cruciate ligament (ACL) injuries commonly lead to translational and rotational tibiofemoral instability. The morphology of the medial tibial eminence (MTE) has received increased attention regarding its role in tibiofemoral stability in ACL-injured knees. Therefore, quantification of MTE dimensions on clinical imaging may help clinicians predict knee stability after ACL injury. Although magnetic resonance imaging (MRI) is routinely obtained in patients with ACL injuries, whether the dimensions of the MTE can be accurate quantified on MRI is unknown. The purpose of this study was to assess the degree of correlation between measurements of MTE height and width on computed tomography (CT) versus MRI. An institutional picture archiving and communication system imaging database was used to identify patients aged between 15 and 60 years who received concurrent MRI and CT of the same knee within a 1-year interval. Knees with significant arthrosis, deformity, intraarticular fracture, or hardware-related artifact that obscured visualization of the MTE were excluded. Mean differences and interstudy agreement between CT and MRI MTE measurements were compared using concordance correlation coefficient (r _c) and Bland-Altman analysis. A total of 41 knees in 38 patients (mean age, 37 years; 82% male) were analyzed. Interrater reliability for CT and MRI measurements was high (intraclass correlation coefficient = 0.740-0.954). On coronal CT and MRI, mean MTE height measurements were 10.4 ± 1.9 and 10.4 ± 1.8 mm, respectively; mean MTE width measurements were 14.6 ± 3.6 and 14.2 ± 3.0 mm, respectively. On sagittal CT and MRI, mean MTE height measurements were 11.6 ± 1.7 and 11.7 ± 1.7 mm, respectively; mean MTE width measurements were 36.5 ± 4.8 and 36.2 ± 5.0 mm, respectively. Good agreement was observed between CT and MRI measurements of MTE height and width on coronal and sagittal planes (r _c = 0.947-0.969). Measurements of MTE height and width were similar on MRI relative to CT on both coronal and sagittal planes. MRI may be suitable for characterizing the dimensions of the MTE when clinically evaluating patients with ACL injuries, potentially allowing for individualized patient care.

Increased posterior tibial slope results in increased incidence of posterior lateral meniscal root tears in ACL reconstruction patients

PURPOSE

While the association with acute anterior cruciate ligament (ACL) tears has been established, other risk factors and associated pathologies which occur with a concomitant lateral meniscal posterior root tear (LMPRT) are not well defined. The purpose of this study was to compare the risk factors and concomitant pathologies between patients with LMPRT and patients without LMPRTs in the setting of a primary ACL tear.

METHODS

Patients with a LMPRT identified at the time of primary ACL reconstruction by a single surgeon were identified. These patients were matched by age and sex to patients undergoing primary ACL reconstruction who were not found to have lateral meniscus root tears (control group) in a 1:1 ratio. Lateral posterior tibial slope (PTS), medial PTS, lateral femoral condyle height and depth, lateral tibial plateau depth, and lateral tibial plateau subluxation were measured on MRI. Anteroposterior full-limb alignment radiographs were used to measure the medial proximal tibia angle (MPTA), the mechanical lateral distal femoral angle (mLDFA), and the mechanical weightbearing axis for the injured extremity.

RESULTS

One-hundred three patients were included in both the LMPRT group and the matched control group. Patients with a LMPRT had a significantly steeper lateral PTS (9.1° vs. 7.0°, p = 0.001), a steeper medial PTS (7.0° vs. 6.0°, p = 0.03), and a greater lateral-to-medial slope asymmetry (2.0° vs. 1.0°, p = 0.001). There were no differences in lateral femoral condyle depth or height, lateral tibial plateau depth, lateral tibial plateau subluxation, MPTA, mLDFA, or mechanical weightbearing axis between groups. There was a significantly increased incidence of medial meniscus ramp lesions in patients with lateral meniscus posterior root tears compared with controls (34.0% vs. 15.5%, odds ratio: 2.8, p = 0.002). There were no associations with concomitant ligament injuries, medial meniscus root tears, or non-ramp tears based on case/control grouping.

CONCLUSION

In conclusion, LMPRTs in the setting of primary ACL injuries were associated with significantly increased lateral and medial PTSs, and increased asymmetry between lateral and medial PTSs. In addition, clinicians should be aware of the increased incidence of concurrent medial meniscal ramp lesions in patients with LMPRTs. Knowledge of these associations helps guide clinical decision-making and counselling of patients in the setting of ACL tears with concomitant LMPRTs.

LEVEL OF EVIDENCE

IV.

Anatomic characteristics of the knee influence the risk of suffering an isolated meniscal injury and the risk factors differ between women and men

PURPOSE

To analyse the relationship between multiple anatomic characteristics of the knee (tibia and femur) and isolated meniscal injury in women and men.

METHODS

Forty-seven patients with isolated medial meniscal injuries, 62 patients with isolated lateral meniscal injuries, and 70 control subjects were included. Medial posterior tibial slope (MTS), lateral posterior tibial slope (LTS), medial tibial plateau depth (MTD), coronal tibial slope (CTS), femoral notch width (NW), femoral condylar width (FCW), intercondylar notch depth (ND), femoral notch width index (NWI), intercondylar notch shape index (NSI), and cruciate ligaments tensity (CLT) were measured from magnetic resonance images. Anatomic characteristics differing between groups were compared, and risk factors for isolated meniscal injury were identified by multivariate forward stepwise logistic regression for men and women separately.

RESULTS

Risk factors for an isolated medial meniscal injury were a steeper MTS and a lowered MTD in men, and a steeper MTS and an increased NWI in women. Risk factors for isolated lateral meniscal injury were a steeper LTS and an increased NW in men, and a steeper LTS and a lowered ND in women. Risk factors for both medial and lateral meniscal injuries were a higher CTS, an increased NWI, and a looser CLT in men, and a higher CTS, an increased NSI, and a looser CLT in women.

CONCLUSION

The anatomic characteristics of the tibial plateau, femur, and cruciate ligaments influence the risk of suffering isolated meniscal injury, and the risk factors differ between men and women. This study provides a reference for developing identification criteria for those at risk of isolated meniscal injury.

LEVEL OF EVIDENCE

III.

The influence of the steep medial posterior tibial slope on medial meniscus tears in adolescent patients: a retrospective case-control study

Background

Several studies have demonstrated a relationship between the posterior tibial slope (PTS) and meniscal tears in adults. However, little is known about the association between the PTS of the adolescents and medial meniscal tears (MMT). The purpose of this study was to evaluate the association between the PTS and MMT in adolescents, and to determine the optimal cut-off values of PTS for discriminating between the MMT and the control groups.

Methods

Between January 2018 and January 2020, a retrospective case-control study was performed. In this study, isolated MMT adolescent patients with no ligamentous injuries were matched by age and sex to a control group of radiologically normal images. The PTS was defined as the angle between the perpendicular line to proximal tibial cortex (PTC) and the tangent line along the tibial plateau. Then, both the medial posterior tibial slope (MPTS) and lateral posterior tibial slope (LPTS) were measured by plain radiographs on the lateral views. In addition, the optimal cut-off values of PTS were determined by the receiver operating characteristic (ROC) curve analysis.

Results

A total of seventy-two patients who met the inclusion criteria were enrolled in the final analysis (36 patients with isolated MMT, 36 controls). The MPTS was greater in the knees with isolated MMT (10.7° ± 2.1°) than that of the control group (8.8° ± 1.7°), showing significant difference (P<0.001). However, there was no significant difference regarding the LPTS between the isolated MMT and controls (11.5 ± 3.4 vs 10.9 ± 2.6, p>0.05). In the ROC curve analysis, the calculated cutoff value of the MPTS discriminating between the groups was 10.3°, with a sensitivity of 73.3% and specificity of 78.9%.

Conclusions

This study demonstrated that steep MPTS is associated with MMT, and MPTS≥10.3° was identified to be a risk factor for MMT in adolescents.

Tibial Slope Can Be Maintained During Medial Opening-Wedge Proximal Tibial Osteotomy With Sagittally Oriented Hinge, Posterior Plate Position, and Knee Hyperextension: A Cadaveric Study

PURPOSE

The purpose of this study is (1) to determine if, when optimizing modern techniques, medial opening-wedge osteotomies can effectively maintain tibial slope and (2) to determine how different magnitude coronal plane corrections affect tibial slope.

METHODS

Proximal tibial osteotomies (PTOs) were performed on 10 fresh-frozen cadaveric knees leaving a consistent lateral hinge, using either a 5-mm or a 10-mm trapezoidal wedged osteotomy plate. Techniques including posterior plate placement; a trapezoidal, sloped plate; and knee hyperextension were used during plate fixation to help close the anterior osteotomy gap. Medial coronal proximal tibia angle and posterior tibial slope were measured preosteotomy, after a 5-mm implant, and after a 10-mm implant using true anteroposterior and lateral fluoroscopic images. Three independent observers performed all radiographic measurements, and intraclass correlation coefficients were calculated.

RESULTS

The 5-mm and 10-mm osteotomy plates increased the coronal medial proximal tibia angle by a mean of 3.4° (range, 3.0°-3.7°) and 7.3° (range, 6.7°-7.7°), respectively. The 5-mm and 10-mm trapezoidal wedged osteotomy plates decreased the posterior tibial slope by a mean of 0.9° (range, 0.5°-1.2°) and 0.3° (range, 0°-0.6°), respectively. Intraobserver reliability was found to be high for both the coronal medial proximal tibia angle (intraclass correlation coefficient [ICC] = 0.897 [0.821-0.946]) and the tibial slope measurements (ICC = 0.761 [0.672-0.826]).

CONCLUSIONS

When optimizing the medial opening-wedge proximal tibial osteotomy, including utilization of a sagittally oriented hinge, placement of a trapezoidal plate posteriorly, and fixation with knee hyperextension, posterior tibial slope can be maintained regardless of the degree of coronal correction.

CLINICAL RELEVANCE

Tibial slope has a significant effect on cruciate ligament stress and a better understanding of coronal plane correction, and its effect on tibial slope is critical when performing proximal tibia osteotomies.

Diagnostic Accuracy of Magnetic Resonance Imaging in the Detection of Type and Location of Meniscus Tears: Comparison with Arthroscopic Findings

Magnetic resonance imaging (MRI) has been widely used for the diagnosis of meniscal tears, but its diagnostic accuracy, depending on the type and location, has not been well investigated. We aimed to evaluate the diagnostic accuracy of MRI by comparing MRI and arthroscopic findings. Preoperative 3.0-T MRI and arthroscopic findings from 2005 to 2018 were reviewed to determine the presence, type, and location of meniscus tears. In addition, subgroup analysis was performed according to anterior cruciate ligament (ACL) injury. The exclusion criteria were as follows: (1) Inflammatory arthritis, (2) other ligament injuries, (3) inability to classify meniscal tears due to degenerative arthritis, (4) over 90 days from MRI to surgery, and (5) incomplete data. Of the 2998 eligible patients, 544 were finally included. The sensitivity and specificity of MRI in determining medial and lateral meniscus tears were 91.8% and 79.9%, and 80.8% and 85.4%, respectively. The accuracy of MRI in the ACL-injured group was lower than that in the ACL-intact group (medial meniscus: 81.7% vs. 88.1%, p = 0.041; 72.9% vs. lateral meniscus: 88.0%, p < 0.001). MRI accuracy was low for the longitudinal tears of the posterior horn of the medial meniscus in the ACL-injured group. MRI could be a diagnostic tool for meniscus tears, but has limited accuracy in their classification of the type and location. Hence, care should be taken during arthroscopic assessment of ACL-injured patients due to low diagnostic accuracy of preoperative MRI.

Repair of the Posterior Lateral Meniscal Root Tear: Suture Anchor Fixation Through the Outside-In Anterior Cruciate Ligament Reconstruction Femoral Tunnel

Posterior lateral meniscus root tears are defined as tears that occur within 9 mm of the posterior lateral meniscus insertion or as avulsions of the insertion. If root tears are left unrepaired, functional alterations and early degenerative changes occur in the affected compartment. Several surgical techniques have been described to reattach the posterior horn of the lateral meniscus, including transtibial pull-out technique and side-to-side repair technique. This surgical technique reports an alternative way to repair posterior lateral meniscus root tears that are associated with or without an anterior cruciate ligament graft tear. The technique involves the placement of a suture anchor on the lateral meniscus root footprint through the outside-in anterior cruciate ligament femoral tunnel, which minimizes the possibility of iatrogenic lesions and facilitates repair.

Steep posterior slope and shallow concave shape of the medial tibial plateau are risk factors for medial meniscus posterior root tears

PURPOSE

Bone morphological factors are important for menisci. Their association with medial meniscus posterior root tears, however, has not yet been studied. This study aimed to compare sagittal medial tibial slope and medial tibial plateau depth between knees with and without medial meniscus posterior root tears.

METHODS

Nine healthy volunteers, 24 patients who underwent anterior cruciate ligament reconstruction, and 36 patients who underwent medial meniscus posterior root pullout repair were included. Magnetic resonance imaging examinations were performed in the 10°-knee-flexed position. The medial tibial slope and medial tibial plateau depth were compared among the groups.

RESULTS

In healthy volunteers, the anterior cruciate ligament reconstruction group, and the medial meniscus posterior root tear group, the medial tibial slopes were 3.5° ± 1.4°, 4.0° ± 1.9°, and 7.2° ± 1.9°, respectively, and the medial tibial plateau depths were 2.1 ± 0.7 mm, 2.2 ± 0.6 mm, and 1.2 ± 0.5 mm, respectively. Patients with medial meniscus posterior root tears had a significantly steep medial tibial slope and shallow medial tibial plateau concavity compared to those of healthy volunteers (P < 0.01) and the anterior cruciate ligament group (P < 0.01). In the multivariate logistic regression analysis, body mass index, medial tibial slope, and medial tibial plateau depth were significantly associated with medial meniscus posterior root tears.

CONCLUSIONS

A steep posterior slope and a shallow concave shape of the medial tibial plateau are risk factors for medial meniscus posterior root tear.

LEVEL OF EVIDENCE

Level III: Case-control study.

Effects of medial meniscal slope and medial posterior tibial slope on the locations of meniscal tears: A retrospective observational study

The aim of this study was to analyze the relationship between medial posterior tibial slope (MPTS) and medial meniscus slope (MMS) with the location of meniscal lesions. We hypothesize that meniscuses with greater MPTS and MMS are more likely to have lesions in posterior horn.A total of 292 patients underwent arthroscopic surgery between January 2014 to September 2019 due to knee osteoarthritis (OA) and meniscal lesions were reviewed. Based upon the location of meniscal tears, patients were categorized as group B (tears in posterior horn) and group A (other sites). MPTS and MMS were measured from magnetic resonance imaging (MRI) slices. Osteoarthritis grade was evaluated in anteroposterior radiographs by the criteria defined by Kellgeren and Lawrence. Demographic data, OA grade, MPTS, and MMS for the 2 groups were compared and analyzed.The group A had 29 (39%) male and 45 (61%) female subjects with a mean age of 57.07 ± 6.79 years. Group B consists of 74 (34%) male and 144 (66%) female subjects with a mean age of 58.90 ± 7.594 years. (P = .067 and P = .458 for age and sex, respectively). In group A, 31 knees (42%) were determined to be Kellgren-Lawrence grade one, 32 knees (43%) grade two, and 11 knees (15%) grade three. In group B, 86 knees (39%) were categorized in grade one, 85 knees (39%) in grade two, and 47 knees (26%) in grade three (P = .085). The mean MPTS was 5.06 ± 2.11 degree for group A and 6.15 ± 2.37 degree for group B (P = .001). The mean MMS for group A was lower than group B (1.38 ± 2.12 degree vs 3.14 ± 2.92 degree; P < .000)This study demonstrated that increased MPTS and MMS may be considered as the risk factors for medial meniscal posterior horn tears.

Lateral meniscal slope negatively affects post-operative anterior tibial translation at 1 year after primary anterior cruciate ligament reconstruction

PURPOSE

The aim of this study was to assess the correlation between posterior tibial slope and meniscal slope over postoperative anterior tibial translation during the first 18 months after primary anterior cruciate ligament (ACL) reconstruction. The main hypothesis was that PTS and MS would be positively correlated with post-operative ATT-SSD after ACL reconstruction.

METHODS

Patients (28 males and 15 females) with confirmed ACL tears were selected from an in-house registry and included if they were over 16 years old, had primary ACL-reconstruction and healthy contralateral knee. Patients meeting one of the following criteria were excluded: previous knee surgeries, intraarticular fractures, associated ligamentous lesions, previous or concomitant meniscectomy or extraarticular procedures. Lateral posterior tibial slope, medial posterior tibial slope, lateral meniscal slope and medial meniscal slope were measured using preoperative MRIs. The side-to-side-difference in anterior tibial translation was evaluated 9-18 months postoperatively.

RESULTS

Forty-three patients were included, (28 males/15 females; mean age 25 ± 8 years). Mean postoperative anterior tibial translation was 1.0 ± 1.1 mm at a mean time of 12 ± 1 months. Mean slope values were: lateral posterior tibial slope 4.7° ± 2.2°, medial posterior tibial slope 4.0° ± 2.8°, lateral meniscal slope 3.0° ± 2.2° and medial meniscal slope 2.0° ± 2.8°. The anterior tibial translation was significantly correlated with lateral meniscal slope (r = 0.63; p < 0.01). For each 1° increase in lateral meniscal slope, a 0.3 mm 95% CI [0.2, 0.4] (p < 0.01) increase in anterior tibial translation was observed. A lateral meniscal slope greater or equal to 4.0° was estimated as optimal threshold for increased risk of abnormal side-to-side difference in postoperative anterior tibial translation (≥ 1.2 mm).

CONCLUSION

The lateral meniscal slope was positively correlated to side-to-side difference in anterior tibial translation after primary ACL reconstruction. A lateral meniscal slope greater or equal to 4.0° was detected as threshold for an increased risk of abnormal side-to-side difference in postoperative anterior tibial translation in patients who underwent primary ACL reconstruction. This confirms that soft tissue slopes have an impact on the outcomes after reconstructive surgery. Level of evidence III.

Analysis of Risk Factors for Ramp Lesions Associated With Anterior Cruciate Ligament Injury

BACKGROUND

The incidence of meniscocapsular junction tears of the medial meniscus posterior horn, known as ramp lesions, is reported to be 9.3% to 23.9%. However, these lesions are not consistently diagnosed with routine arthroscopic exploration and magnetic resonance imaging (MRI).

PURPOSE

To determine risk factors associated with ramp lesions in anterior cruciate ligament-injured knees.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 275 patients undergoing anterior cruciate ligament reconstruction between June 2011 and March 2019 were included in this study. Exclusion criteria were revisions, fracture histories, and multiple-ligament injuries other than medial collateral ligament injury. Patients were divided into 2 groups, those with and without ramp lesions according to arthroscopic diagnosis. Binary logistic regression was used to analyze risk factors: age, sex, body mass index, time from injury to surgery (<3 or ≥3 months), mechanism of injury (contact/noncontact), Segond fracture, side-to-side laxity, location of bone contusion, medial and lateral tibial/meniscal slope, and mechanical axis angle. Receiver operating characteristic curves and area under the curve were evaluated. A prediction model was developed by multivariable regression with generalized estimating equations.

RESULTS

Overall, 95 patients (34.5%) were confirmed as having a ramp lesion. The sensitivity of MRI for ramp lesions was 85.3%, and specificity was 78.3%. Significant risk factors for ramp lesion were as follows: posterior medial tibial plateau bone contusion on MRI (odds ratio [OR], 4.201; 95% CI, 2.081-8.482; P < .001), ≥3 months from injury (OR, 4.818; 95% CI, 2.158-10.757; P < .001), varus knee >3° (OR, 2.339; 95% CI, 1.048-5.217; P = .038), steeper medial tibial slope (OR, 1.289; 95% CI, 1.002-1.66; P = .049) and meniscal slope (OR, 1.464; 95% CI, 1.137-1.884; P = .003), and gradual lateral tibial slope (OR, 0.775; 95% CI, 0.657-0.914; P = .002). The area under the curve for the prediction model developed by logistic regression was 0.779 (sensitivity, 75.8%; specificity, 71.7%; P < .001) for ramp lesions.

CONCLUSION

Care should be taken with patients who have significant risk factors for ramp lesions, including bone contusion at the posterior medial tibial plateau, chronic injury, steeper medial tibial and meniscal slope, gradual lateral tibial slope, and varus knee >3°.

Increased Posterior Tibial Slope in Patients With Osgood-Schlatter Disease: A New Association

BACKGROUND

Osgood-Schlatter disease (OSD) is a traction apophysitis of the tibial tubercle caused by repetitive strain and chronic avulsion from the patellar tendon. No widely accepted anatomic risk factors have been associated with OSD.

PURPOSE

To determine if OSD is associated with increased posterior tibial slope (PTS).

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Forty knees with OSD and 32 control knees examined by the senior author between 2008 and 2019 were included. Patients 10 to 15 years of age with a clinical diagnosis of OSD and available lateral radiograph and magnetic resonance imaging (MRI) were eligible. Age- and sex-matched patients with a history of knee pain but no evidence of OSD on clinical examination and without significant pathology on lateral radiograph and MRI were included in the control group. PTS was defined as the angle between a reference line perpendicular to the proximal anatomic axis and a line drawn tangent to the uppermost anterior and posterior edges of the medial tibial plateau. Measurements were carried out in duplicate on true lateral radiographs by 2 blinded investigators. Interrater reliability of PTS measurements was evaluated using intraclass correlation coefficient (ICC). The independent samples t test was used to compare PTS between the OSD and control knees.

RESULTS

The mean age was 12.6 ± 1.6 years and 51% (37/72) of the knees were from male youth. There were no differences in age, sex, and laterality of knees between the OSD and control groups. The mean PTS was significantly higher in the OSD group (12.23°± 3.58°) compared with the control group (8.82°± 2.76°; P < .001). The ICC was 0.931 (95% CI, 0.890-0.957), indicating almost perfect interrater reliability.

CONCLUSION

This study identifies an association between OSD and increased PTS. The clinical implications of this finding have not yet been elucidated. It may be speculated that in patients with OSD, stress from the extensor mechanism through the patellar tendon loads the anterior portion of the tibia disproportionately to the posterior segment, thereby resulting in asymmetric growth and an increased PTS.