Biomechanical evaluation of tibial eminence fractures using suture fixation

Arthroscopic fixation for tibial eminence fractures: A clinical retrospective study of cannulated screws versus transosseous anchor knot fixation techniques with suture anchors

BACKGROUND

A variety of different techniques or methods for treatment of tibial eminence fracture (TEF) have been reported, but there is still controversy on the optimum choice for treating TEFs. The aim of the current work was to compare the clinical outcomes of arthroscopic cannulated screw fixation and a new arthroscopic anchor fixation technique for tibial eminence fracture.

METHODS

We included 69 isolated tibial eminence fracture patients from June 2012 to February 2017; 36 patients received the cannulated screw fixation and 33 received the transosseous anchor knot (TAK) fixation under arthroscopy. The two techniques were performed by two different high-volume surgeons. The clinical efficacies of the two techniques were assessed by radiographs, extension deficit, flexion deficit, anterior drawer test (ADT), Lachman test, Lysholm scores and International Knee Documentation Committee (IKDC) scores in follow ups.

RESULTS

Patients were followed up for 35.8 months on average (range, 24-54 months). There were 40 (58%) males and 29 (42%) females included, and four (6%) patients were ＜18 years old. Asymptomatic grade II laxity was found in two patients in the CS group and three patients in the TAK group from the results of Lachman test. Postoperative radiographs in all patients showed anatomic reductions and bony unions were achieved within 12 weeks. There were no significant differences in extension deficit, flexion deficit, ADT, Lachman test, Lysholm scores and IKDC scores between groups (P > 0.05).

CONCLUSIONS

The TAK technique shows satisfactory clinical and radiological outcomes equal to the cannulated screw fixation, which is applicable for TEFs as a reliable effective method.

Effect of Skeletal Maturity on Fixation Techniques for Tibial Eminence Fractures

Background:

Several fixation methods have been reported for the operative treatment of tibial eminence fractures. Previous biomechanical studies have demonstrated that suture fixation may be a stronger construct; however, the maturity status of these specimens was not scrutinized.

Purpose:

To examine if suture fixation remains a biomechanically superior fixation method to screw fixation in both skeletally mature and immature specimens.

Study Design:

Controlled laboratory study.

Methods:

Sixteen total matched porcine (Yorkshire) knees (8 skeletally immature knees and 8 skeletally mature knees) were procured, and a standardized tibial eminence fracture was created. In each age-matched group of knees, 4 knees underwent randomization to fixation with 2 screws while 4 knees were randomized to fixation using a dual-suture technique. Once fixation was complete, the specimens underwent cyclic loading (200 cycles) in the anteroposterior plane of the tibia and load-to-failure testing, both with the knee positioned at 30° of flexion. Relevant measurements were recorded, and data were analyzed.

Results:

Among mature specimens, load to failure was 1.9 times higher in the suture fixation group compared with the screw fixation group (1318.84 ± 305.55 vs 711.66 ± 279.95 N, respectively; P = .03). The load to failure was not significantly different between the groups in immature specimens (suture: 470.00 ± 161.91 N vs screw: 348.79 ± 102.46; P = .08).

Conclusion:

These findings suggest that suture fixation may represent a better construct choice for fixation of tibial eminence fractures in the skeletally mature population. However, in the skeletally immature population, fixation with screws or suture may be equivalent. Displacement after cyclic loading did not appear to differ by fixation method, nor did stiffness.

Clinical Relevance:

A stronger fixation construct may be beneficial and allow for earlier range of motion to help potentially decrease postoperative stiffness. Clinical studies are warranted to see if these results may be replicated in humans.

Anterior Cruciate Ligament Tear Following Operative Treatment of Pediatric Tibial Eminence Fractures in a Multicenter Cohort

BACKGROUND

Postoperative ipsilateral anterior cruciate ligament (ACL) tears after tibial eminence fracture fixation has been previously noted in the literature. This study aims to describe the prevalence of and risk factors for postoperative ACL tears in a cohort of patients operatively treated for tibial eminence fracture.

METHODS

A retrospective review of children undergoing treatment of a tibial eminence fracture at 10 tertiary care children's hospitals was performed. The primary outcome of interest was subsequent ACL rupture. Incidence of ACL tear was recorded for the entire cohort. Patients who sustained a postoperative ACL tear were compared with those without ACL tear and analyzed for demographics and risk factors. A subgroup analysis was performed on patients with a minimum of 2-year follow-up data or those who had met the primary outcome (ACL tear) before 2 years.

RESULTS

A total of 385 pediatric patients were reviewed. 2.6% of the cohort experienced a subsequent ACL tear. The median follow-up time was 6.5 months (SD=6.4 mo). Subsequent ACL tears occurred at a median of 10.2 months (SD=19.5 mo) postoperatively. There was a statistically significant association with higher grade tibial spine fractures (Myers and McKeever type III and IV) and subsequent ACL tear (P=0.01). Patients with a subsequent ACL tear were older on average (13.5 vs. 12.2 y old), however, this difference was not statistically significant (P=0.08). Subgroup analysis of 46 patients who had a 2-year follow-up or sustained an ACL tear before 2 years showed a 21.7% incidence of a subsequent ACL tear. There was a statistically significant association with higher grade tibial spine fractures (Myers and McKeever type III and IV) and subsequent ACL rupture (P=0.006) in this subgroup. Postoperative ACL tears occurred in patients who were older at the time that they sustained their original tibial eminence fracture (13.4 vs. 11.3 y old, P=0.035).

CONCLUSIONS

Ipsilateral ACL tears following operatively treated pediatric tibial eminence fractures in a large multicenter cohort occurred at a rate of 2.6%. However, in those with at least 2 years of follow-up, the incidence was 21.7%. Subsequent ACL tear was more likely in those with completely displaced (type III or IV) tibial eminence fractures and older patients.

LEVEL OF EVIDENCE

Level III-retrospective cohort study.

Biomechanical evaluation of physeal-sparing fixation methods in tibial eminence fractures

BACKGROUND

Tibial eminence fractures occur most commonly in skeletally immature children. Several techniques using physeal-sparing fracture fixation have been described, but their structural properties have not been evaluated.

PURPOSE

To determine the strength and resistance to displacement of physeal-sparing techniques used to fix tibial eminence fractures.

STUDY DESIGN

Controlled laboratory study.

METHODS

Skeletally immature porcine knees were randomized into 4 treatment groups: (1) ultra-high molecular weight polyethylene suture-suture button (UHMWPE/SB), (2) suture anchor, (3) polydioxanone suture-suture button (PDS/SB), and (4) screw fixation. A prospective analysis of bone mineral density using dual-energy x-ray absorptiometry was performed on all specimens. Fracture fragments were created in a standardized manner and measured for size comparison. After fracture fixation, biomechanical testing was performed with cyclical and load-to-failure protocols by loading the tibia with an anterior shear force.

RESULTS

In load-to-failure testing, screw fixation had a significantly lower median peak failure load (186.4 N; lower quartile [LQ], 158.4 N; upper quartile [UQ], 232.6 N) than did UHMWPE/SB (465.8 N; LQ, 397.8 N; UQ, 527.8 N), suture anchors (440.5 N; LQ, 323.0 N; UQ, 562.3 N), and PDS/SB (404.3 N; LQ, 385.9 N; UQ, 415.6 N). UHMWPE/SB demonstrated a significantly higher median yield load (465.8 N; LQ, 397.8 N; UQ, 527.8 N) than did PDS/SB (306.7 N; LQ, 271.4, N; UQ, 405.7 N) and screw fixation (179.0 N; LQ, 120.2 N; UQ, 232.5 N). During cyclical testing, screw fixation demonstrated significantly lower percentage survival of specimens (0%) compared with the other groups (UHMWPE/SB, 100%; suture anchor, 78%; PDS/SB, 78%). After 1000 cycles of loading, PDS/SB fixation had significantly more median creep (6.76 mm; LQ, 6.34 mm; UQ, 8.28 mm) than did UHMWPE/SB (4.43 mm; LQ, 3.80 mm; UQ, 4.73 mm) and suture anchor fixation (3.06 mm; LQ, 2.59 mm; UQ, 4.28 mm). The lowest median stiffness was observed in the PDS/SB group (48.6 N/mm; LQ, 45.3 N/mm; UQ, 54.2 N/mm). UHMWPE/SB fixation demonstrated a significantly higher median peak failure load after cyclic testing (469.0 N; LQ, 380.6 N; UQ, 507.2 N) than did PDS/SB (237.7 N; LQ, 197.3 N; UQ, 298.3 N) and screw fixation (132.4 N; LQ, 123.7 N; UQ, 180.9 N). Suture anchor fixation had significantly more variance, as demonstrated by width of interquartile range, in peak failure load, yield load, and creep than did other techniques.

CONCLUSION

Physeal-sparing fixation of tibial eminence fractures with UHMWPE suture-suture button is biomechanically superior to both PDS suture-suture button and a single screw at the time of surgery and provides more consistent fixation than do suture anchors.

CLINICAL RELEVANCE

Suture anchors provide inconsistent fixation for tibial eminence fractures.