Morphometric study of gender difference in osteoarthritis posterior tibial slope using three-dimensional magnetic resonance imaging

Anterior metaphyseal angle; much less individual variation in determining the posterior slope of the tibia

BACKGROUND

The question of how to specify the posterior tilt of the tibia during arthroplasty operations remains unclear. The most current opinion is that a design whereby incisions are made in parallel with the individual pre-arthritic posterior tilt will yield better post-operational results. However, the wide range of inter-individual variations of posterior tilt of the tibia and the difficult task of identifying the shaft axis of the tibia through standard lateral radiographs are the main obstacles to this particular method. Therefore, there is a need for another reference line that can be measured with plain radiography and yields less inter-individual variation. The hypothesis of this study was that the angle formed between the anterior metaphyseal line of the proximal tibia and the tibial plateau would prove to be less variable across individuals.

METHODS

Long-shot radiographs of non-rotating lateral tibias of 85 patients aged between 18 and 38 years were analysed. The angle forming between the anterior metaphyseal line of the proximal tibia and the slope of the tibial plateau, and the posterior slope angle was measured by 2 separate observers using the classical method.

RESULTS

From the measurements of the posterior slope angle taken with the classical method, 38% (33/85) of the patients were within the ±2-degree range of the mean, and the anterior metaphyseal angle was within ±2 degrees of the mean in 75% (64/85) of the total patients. 44.23% variation (CoV) in posterior slop degrees, 2.73% (CoV) variation in the anterior metaphyseal angle measured by the same researchers. The difference between the percentages of variation was also found to be statistically significant. (z = 15.36, p = 0.000).

CONCLUSION

The anterior metaphyseal angle can be utilized to predict the individual posterior slope. Nevertheless, further large-scale, multicentre studies are needed to establish a mean value for the population.

Reappraisal of the proximal tibia anatomy in Turkish population

OBJECTIVE

Total knee arthroplasty has been popular in recent years. Morphometry of proximal tibia is important for surgeons to perform successful total knee arthroplasty. Aim of this study was to reappraise the proximal tibia morphometry.

METHODS

In this study, 57 human dry tibia were evaluated. Anteroposterior and mediolateral dimensions of tibial condyles, maximum width of superior articular surface and length of tibia were measured. Furthermore, morphometric measurements of the intercondylar area and Gerdy's tubercle (infracondylar tibial tubercle) were done. All measurements were performed by two observers using a digital caliper.

RESULTS

Mean anteroposterior and mediolateral dimensions of medial tibial condyle were found 39.76 and 23.27 mm, respectively. Mean anteroposterior and mediolateral dimensions of lateral tibial condyle were measured 34.72 and 21.83 mm, respectively. Mean anteroposterior dimension of intercondylar area was 41.62 mm. Shape of the Gerdy's tubercle was oval in 76.8%, irregular in 12.5%, and triangular in 10.7%. Texture of the tubercle was smooth in 85.7% and rough in 14.3%. Mean superoinferior and mediolateral dimensions of Gerdy's tubercle were 12.28 and 10.27 mm, respectively. Anteroposterior and mediolateral dimensions of tibial condyles were significantly higher (p < 0.05) for the medial condyle. Positive and statistically significant correlations were found between the tibial length and the other parameters (p < 0.05, r > 0.40).

CONCLUSION

The morphometric data of tibial plateau are important for surgeons during total knee arthroplasty. The superoinferior and mediolateral dimensions of the Gerdy's tubercle, the distance between Gerdy's tubercle and tibial tuberosity, the distance between Gerdy's tubercle and lateral tibial plateau were measured for the first time in our study. The data obtained from this study can be used as a guideline in designing tibial component of the total knee prosthesis in Turkish population. In arthroplasty, patient-specific prosthetic implants may eradicate implant mismatch in the near future.

Relevance of the Tibial Slope on Functional Outcomes in ACL-Deficient and ACL Intact Fixed-Bearing Medial Unicompartmental Knee Arthroplasty

BACKGROUND

Excessive posterior tibial slope in medial unicompartmental knee arthroplasty (UKA) has been implicated in early failure. The purpose of this study was to evaluate the relationship between preoperative posterior tibial slope and postoperative slope of the implant (PSI) on outcomes in patients with anterior cruciate ligament (ACL) intact and ACL-deficient knees after fixed-bearing medial UKA.

METHODS

Patients who underwent a medial UKA between 2002 and 2017 with a minimum 3-year follow-up were included. Preoperative posterior tibial slope and postoperative PSI were measured. Outcomes measures included Knee Injury and Osteoarthritis Outcomes Score (KOOS) subscales, Lysholm, and VR-12. Failure was defined as conversion to total knee arthroplasty.

RESULTS

Of 241 knees undergoing UKA, 131 patients (70 women, 61 men; average age of 65 ± 10 years (average BMI of 27.9 ± 4) were included. For all patients, survivorship was 98% at 5 years and 96% at 10 years with a mean survival time for UKA was 15.2 years [95% CI: 14.6-15.7]. No failure had a PSI >7°. There were no superficial or deep infections. There were no significant differences in outcome scores between the ACL intact and the ACL-deficient group; therefore, the data were combined for analysis. At mean 8-year follow-up, KOOS pain scores were better in patients with PSI ≤7° (87 ± 16) than those with PSI >7° (81 ± 15). 76% of patients with PSI ≤7° reached the Patient Acceptable Symptom State for KOOS pain; whereas, 59% of patients with PSI >7° reached PASS for KOOS pain (P = .015).

CONCLUSION

Patients with postoperative posterior slope of the tibial implant >7° had significantly worse postoperative pain, without conversion to TKA, and with maintenance of high function. In ACL deficient and intact knees, nonrobotically-assisted, fixed-bearing medial UKA had a 96% survivorship at 10 years.

The posterior horn of the medial and lateral meniscus both reduce the effective posterior tibial slope: a radiographic MRI study

PURPOSE

The purpose of this study was to quantify the posterior horn meniscal slope and determine its contribution to the reduction in posterior tibial slope.

METHODS

Patients aged between 16 and 60 years and had intact menisci with no evidence of previous injury or surgery were included. Patients with radiological evidence of osteoarthritis Grade II-IV, any acute or chronic meniscus injuries, fractures, and ligamentous injuries were excluded. The posterior bony slope (PTS) and the meniscus slope (MS) of the posterior horns were measured at 25, 50, and 75% from the medial and lateral borders of the tibial plateau.

RESULTS

325 MR images (mean age 37.1 ± 10.9 years) were included. There were 194 males and 131 females, with 162 left and 163 right knees. The PTS in the medial compartment ranged from (-) 2.8° to 3.7° and from (-) 1.3° to 1.9° in the lateral compartment (p = 0.0001). The MS in the medial compartment ranged from 27.4° to 28.2°, and from 27.8° to 28.7° in the lateral compartment (p > 0.05). The differences between the medial and lateral knee compartment were statistically significant. At the 25% interval the p level was 0.037, at 50% p = 0.00001, and at 75% p = 0.0001. There were no significant between gender differences.

CONCLUSIONS

The results of this study demonstrated a significant reduction in posterior tibial bone slope by the posterior horns of both the medial and lateral meniscus, from a mean of (-) 1° to 2° to a more horizontal anterior slope. The posterior bone slope was larger in the medial compartment by 1°, resulting in a smaller slope reduction in the lateral compartment.

Femoral trochlear morphology is associated with anterior cruciate ligament injury in skeletally immature patients

PURPOSE

Knee joint morphology is a known contributor to anterior cruciate ligament (ACL) injury, and the shape of the distal femur condyle is one of the associated factors. However, the relationship between femoral trochlear morphology and ACL injury is unclear, especially in pediatric patients. Therefore, the present study aimed to evaluate the effect of femoral trochlear morphology on ACL injury in pediatric patients and investigate the possibility of gender differences.

METHODS

In total, 116 skeletally immature children aged 3-18 years with primary ACL injuries were matched with a control group of 116 skeletally immature children. Lateral trochlear inclination, trochlear facet asymmetry, trochlear depth, and sulcus angle were evaluated using magnetic resonance imaging (MRI). Differences between patient groups and gender were investigated. Receiver-operating characteristic (ROC) curves were constructed to obtain the sensitivity and specificity of all parameters.

RESULTS

A significant difference was observed in the sulcus angle and trochlear inclination between the ACL injury and control groups (p < 0.05). No significant difference was observed between the ACL injury and control groups with respect to the anatomic patellar instability risk factors. All parameters showed an area under the curve of 0.6 in the ROC analysis, indicative of failure of the diagnostic test.

CONCLUSIONS

There was a significant association between femoral trochlear morphology and increased risk of ACL injury in pediatric patients. No gender difference was found except in the trochlear depth. It was showed that the difference in trochlear morphology should be considered between normal children and pediatric patients with ACL injury to increase the awareness regarding ACL injuries.

LEVEL OF EVIDENCE

III.

Difference in sex and the effect of a dominant lower extremity in the posterior tibial slope angle in healthy Japanese subjects

Background/objective

Anterior cruciate ligament injuries are prone to re-injury, and it is crucial to prevent the primary injury. One of the anatomical risk factors for anterior cruciate ligament injury is the posterior tibial slope angle. Investigating the characteristics of healthy individuals with respect to the posterior tibial slope angle is important to elucidate the risk of developing anterior cruciate ligament injuries. The purpose of this study was to determine the characteristics related to sex and of the posterior tibial slope angle in healthy Japanese subjects, and the effect of the dominant lower extremity.

Methods

Sixty-two knees of 31 healthy Japanese college students (15 males and 16 females) were included in this study. Magnetic resonance images of both knee joints of the subjects were measured using a 0.3 T scanner. The medial and lateral posterior tibial slope angles were measured from the obtained magnetic resonance images. Magnetic resonance images of the knee joint of the dominant lower extremity were used to compare differences in sexes between the medial and lateral posterior tibial slope angles. Bilateral knee joint magnetic resonance images were used to compare the dominant and non-dominant lower extremities. Independent t-tests were used to compare the differences regarding sex in the medial and lateral posterior tibial slope angles and to compare the dominant and non-dominant lower extremities.

Results

A comparison of the mean lateral posterior tibial slope angle showed that males had a 8.8 ± 1.7° angle, while females had a 10.3 ± 2.2° angle, which was significantly greater (p = 0.047). There was no significant difference comparing the posterior tibial slope angle between the dominant and non-dominant lower extremities (p = 0.430).

Conclusions

From the result of this study, the lateral posterior tibial slope angle was significantly higher in the female group than in the male group. However, both the medial and lateral posterior tibial slope angles were found to be unaffected by the dominant lower extremity.

Biomechanical and Clinical Effect of Patient-Specific or Customized Knee Implants: A Review

(1) Background: Although knee arthroplasty or knee replacement is already an effective clinical treatment, it continues to undergo clinical and biomechanical improvements. For an increasing number of conditions, prosthesis based on an individual patient's anatomy is a promising treatment. The aims of this review were to evaluate the clinical and biomechanical efficacy of patient-specific knee prosthesis, explore its future direction, and summarize any published comparative studies. (2) Methods: We searched the PubMed, MEDLINE, Embase, and Scopus databases for articles published prior to February 1, 2020, with the keywords "customized knee prosthesis" and "patient-specific knee prosthesis". We excluded patient-specific instrument techniques. (3) Results: Fifty-seven articles met the inclusion criteria. In general, clinical improvement was greater with a patient-specific knee prosthesis than with a conventional knee prosthesis. In addition, patient-specific prosthesis showed improved biomechanical effect than conventional prosthesis. However, in one study, patient-specific unicompartmental knee arthroplasty showed a relatively high rate of aseptic loosening, particularly femoral component loosening, in the short- to medium-term follow-up. (4) Conclusions: A patient-specific prosthesis provides a more accurate resection and fit of components, yields significant postoperative improvements, and exhibits a high level of patient satisfaction over the short to medium term compared with a conventional prosthesis. However, the tibial insert design of the current patient-specific knee prosthesis does not follow the tibial plateau curvature.