Transpatellar bone tunnels perforating the lateral or anterior cortex increase the risk of patellar fracture in MPFL reconstruction: a finite element analysis and survey of the International Patellofemoral Study Group

Computational evaluation of wire position using separate vertical wire technique and candy box technique for the fixation of inferior pole patellar fractures: a finite element analysis

The separate vertical wire (SVW) technique and the improved candy box (CB) technique have been proposed for treating inferior pole patellar fractures. However, there is still a lack of clear explanation regarding the location of the wire passing through the patella. Five models of SVW techniques were established in different positions. Finite element analysis was then conducted to determine the optimal bone tunnel position for the SVW technique. Based on these findings, six groups of finite element models were created for CB techniques. The maximum displacement and stress on both the patella and steel wire were compared among these groups under 100-N, 200-N, 300-N, 400-N, and 500-N force loads. The results indicated that, in the SVW technique, the steel wire group near the fracture end of the longitudinal bone tunnel showed minimal displacement and stress on the patella when subjected to different forces. On the other hand, in the CB technique, both the patella and wire experienced minimal stress when a transverse bone tunnel wire was placed near the upper posterior aspect of patella. In conclusion, the SVW technique may require the bone tunnel wire to be positioned near the fractured end of the lower pole of the patella. On the other hand, in CB technique, the transverse bone tunnel wire passing through the patella may be close to its upper posterior aspect. However, further validation is necessary through comprehensive finite element analysis and additional biomechanical experiments.

Previous Extensor Mechanism Repair Is Associated With Increased Rates of Surgical Complications Following Total Knee Arthroplasty: A Propensity-matched Analysis

Background

Although extensor mechanism failure following total knee arthroplasty (TKA) is a devastating complication and has been heavily studied in the literature, the impact of extensor mechanism rupture and concomitant repair prior to TKA has not previously been evaluated. The purpose of this investigation was to evaluate how quadriceps and/or patellar tendon repairs prior to TKA would impact medical and surgery-related complications following TKA.

Methods

The PearlDiver database was retrospectively reviewed to identify all primary TKA patients from 2010 to 2019. Patients who underwent quadriceps or patellar tendon repair prior to TKA were matched using a propensity score algorithm to a control cohort. We compared medical and surgical complication rates, emergency room visits, readmissions, and 90-day cost of care between the groups.

Results

A total of 1197 patients underwent extensor mechanism repair prior to TKA and were matched to 11,970 patients who did not undergo repair prior to TKA. Patients who underwent extensor mechanism repair had higher rates of 90-day medical complications, as well as 1-year surgery-related complications including revision TKA (odds ratio [OR] 6.06; P < .001), lysis of adhesions (OR 2.18; P = .026), aseptic loosening (OR 2.21; P = .018), infection (OR 7.58; P < .001), and fracture (OR 8.53; P < .001). Patients with prior extensor mechanism repair were more likely to return to the emergency department (OR 1.66; P < .001) and become readmitted (OR 4.15; P < .001) within 90 days.

Conclusions

Patients with previous extensor mechanism repair exhibited higher medical and surgery-related complications, including lysis of adhesions, following TKA than a control cohort. These findings may suggest that patients may require additional surveillance in the early postoperative period to avoid these disastrous complications following primary TKA.

Model Properties and Clinical Application in the Finite Element Analysis of Knee Joint: A Review

The knee is the most complex joint in the human body, including bony structures like the femur, tibia, fibula, and patella, and soft tissues like menisci, ligaments, muscles, and tendons. Complex anatomical structures of the knee joint make it difficult to conduct precise biomechanical research and explore the mechanism of movement and injury. The finite element model (FEM), as an important engineering analysis technique, has been widely used in many fields of bioengineering research. The FEM has advantages in the biomechanical analysis of objects with complex structures. Researchers can use this technology to construct a human knee joint model and perform biomechanical analysis on it. At the same time, finite element analysis can effectively evaluate variables such as stress, strain, displacement, and rotation, helping to predict injury mechanisms and optimize surgical techniques, which make up for the shortcomings of traditional biomechanics experimental research. However, few papers introduce what material properties should be selected for each anatomic structure of knee FEM to meet different research purposes. Based on previous finite element studies of the knee joint, this paper summarizes various modeling strategies and applications, serving as a reference for constructing knee joint models and research design.

Candy box technique for the fixation of inferior pole patellar fractures: finite element analysis and biomechanical experiments

BACKGROUND

Maintaining effective reduction and firm fixation in inferior pole patellar fractures is a highly challenging task. There are various treatment methods available; although tension-band wiring combined with cerclage wiring (TBWC) is the mainstream approach, its effectiveness is limited. Herein, we propose and evaluate a new technique called candy box (CB), based on separate vertical wiring (SVW), for the treatment of inferior pole patellar fractures. Specifically, we provide biomechanical evidence for its clinical application.

METHODS

Five fixation models were built: SVW combined with cerclage wiring (SVWC); TBWC; modified SVW with the middle (MSVW-A) or upper (MSVW-B) 1/3 of the steel wire reserved, and CB. A finite element analysis was performed to compare the displacement and stress under 100-N, 200-N, 300-N, 400-N and 500-N force loads. Three-dimensional printing technology was utilized to create fracture models, and the average displacement of each model group was compared under a 500-N force.

RESULTS

The results of the finite element analysis indicate that CB technology exhibits significantly lower maximum displacement, bone stress, and wire stress compared to that with other technologies under different loads. Additionally, in biomechanical experiments, the average force displacement in the CB group was significantly smaller than that with other methods under a 500-N force (P < 0.05).

CONCLUSIONS

CB technology has the potential to overcome the limitations of current techniques due to its superior biomechanical characteristics. By incorporating early functional exercise and ensuring strong internal fixation, patient prognosis could be enhanced. However, further clinical trials are needed to fully evaluate the therapeutic effects of CB technology.

Estimating the adequacy of the free quadriceps tendon autograft length using anthropometric measures in anterior cruciate ligament reconstruction

OBJECTIVE

This prospective study aimed to predict the adequacy of free quadriceps tendon (QT) autograft length using simple anthropometric measures.

MATERIALS AND METHODS

One hundred and eighty-four consecutive patients who underwent knee high-resolution MRI were enrolled in this study. The QT and native anterior cruciate ligament (ACL) length were measured using the oblique sagittal section. The adequate free QT length was calculated using the native ACL length and 30 mm for femoral and tibial tunnels in each patient. A QT shorter than the calculated length was considered inadequate. Age, sex, height, weight, body mass index, thigh circumference, and activity score were used to predict the adequacy of QT length with regression analysis.

RESULTS

There were 92 men and 92 women with a mean age of 34.1 ± 8.0 years (range 18-45). The mean QT and ACL lengths were 69.0 ± 8.8 mm (range 48.1-90.3 mm) and 35.6 ± 2.5 mm (range 29.2-42.6 mm), respectively. The QT and the ACL lengths were longer in men (p < 0.001 for both). Twenty-three men and 39 women (total: 62, 33.7%) had inadequate QT length for a free QT autograft, and 6 patients (3 males, 3 females, 3.3%) had inadequate QT length with the bone block technique. There was a weak positive correlation between QT length and height (p < 0.001), weight (p < 0.001), and activity score (p = 0.007). Height was the only independent variable that predicted the QT length adequacy (r² = 0.051, p = 0.009) but ROC analysis showed that height did not have an ability to detect a subject with an inadequate QT length (AUC: 0.384, 95% CI 0.300-0.468).

CONCLUSIONS

Free QT autografts may be inadequate in one-third of the patients, while a QT autograft with a bone block is almost always sufficient. Inadequate free QT autograft is more common in women. Although QT length correlated with height, it cannot be used as an accurate diagnostic tool to identify patients with an inadequate QT autograft. Preoperative measurement of the ACL and QT lengths by MRI might be beneficial to decide whether QT is usable, especially when harvesting without a bone block.

LEVEL OF EVIDENCE

Level II, diagnostic, prospective cohort study.

Tibial slope correction combined with second revision ACLR grants good clinical outcomes and prevents graft rupture at 7-15-year follow-up

PURPOSE

To update previously published outcomes (at 2-8 years) of second revision anterior cruciate ligament reconstruction (ACLR) combined with tibial deflexion osteotomy (TDO), after an interval of 5 more years (at 7-15 years), and monitor evolution of clinical scores and progression of osteoarthritis.

METHODS

The initial retrospective consecutive series included nine patients that underwent one-stage second revision ACLR with TDO, all of whom were contacted for second follow-up at minimum 7 years. An independent observer collected IKDC-SKF, the Lysholm score, and assessed radiographs for signs of osteoarthritis.

RESULTS

Of the nine original patients, seven were assessed at the clinic, one could only be assessed by telephone, and one was lost to follow-up. At final follow-up of 9.9 ± 3.0 years, the eight patients assessed maintained or improved clinical scores, compared to the previous follow-up at 4.0 ± 2.9 years. The mean Lysholm score improved from 73.8 ± 5.8 (65-82) to 84.5 ± 11.9 (59-95), and IKDC improved from 71.6 ± 6.2 (62-79) to 82.9 ± 12.1 (61-98). Of the three patients that had signs of arthritis at the previous follow-up, the stage of osteoarthritis increased in one (from grade 2 to grade 3), remained unchanged in one, and could not be assessed in one.

CONCLUSION

At 7-15 years following second revision ACLR with TDO, patients maintained or improved clinical scores compared to the previous follow-up at 2-8 years, without retears or reoperations. Although eight of the nine knees had meniscectomies or meniscal sutures, osteoarthritis progressed in only one of the six knees that had signs of arthritis at the previous follow-up. These results confirm that TDO can protect the ACL graft from retear, with minimal progression of osteoarthritis and/or risks of meniscal tears, suggesting that correction of excessive tibial slope should be considered when performing ACLR, whether a revision or primary procedure.

An increased posterior tibial slope is associated with a higher risk of graft failure following ACL reconstruction: a systematic review

PURPOSE

The posterior tibial slope (PTS) is considered a risk factor for anterior cruciate ligament (ACL) injury. However, the influence of PTS on graft failure following ACL reconstruction remains relatively unknown. Therefore, this systematic review was conducted to investigate whether PTS could be a potential risk factor for graft failure after ACL reconstruction.

METHODS

PubMed, EMBASE, Cochrane Library, Web of Science, China National Knowledge Infrastructure Database, and Wanfang Database were comprehensively searched from inception to March 31, 2021. Observational studies reporting the associations of medial tibial plateau slope (MTPS) or lateral tibial plateau slope (LTPS) with graft failure after ACL reconstruction were evaluated.

RESULTS

Twenty studies involving 12 case-control studies, 4 retrospective studies and 4 cross-sectional studies including 5326 patients met the final inclusion criteria. The high heterogeneity and the characteristics of nonrandomized controlled trials limited data synthesis. Fifteen of the 20 included studies detected a significant association between increased PTS and ACL graft failure, while 5 studies concluded that increased PTS was not associated with ACL graft failure. Ten studies suggested that MTPS is associated with ACL graft failure, and six studies suggested that LTPS is associated with ACL graft failure. The mean MTPS values for nonfailure group ranged from 3.5° ± 2.5° to 14.4° ± 2.8°. For the graft failure group, MTPS ranged from 4.71° ± 2.41° to 17.2° ± 2.2°. The mean LTPS values for nonfailure group ranged from 2.9° ± 2.1° to 11.9° ± 3.0°. For the graft failure group, LTPS ranged from 5.5° ± 3.0° to 13.3° ± 3.0°. The reported PTS values that caused ACL graft failure was greater than 7.4° to 17°.

CONCLUSION

Based on the current clinical evidence, increased PTS is associated with a higher risk of ACL graft failure after ACL reconstruction. Despite various methods of measuring PTS have high reliability, there is still vast disagreement in the actual value of PTS.

LEVEL OF EVIDENCE

IV.