Suture repair of patellar inferior pole fracture: Transosseous tunnel suture compared with anchor suture

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.

Suture Anchor Fixation Has Less Gap Formation and No Difference in Complications or Revisions for Patellar Tendon Repair: A Systematic Review

PURPOSE

To evaluate the literature on suture anchor (SA) usage for patellar tendon repair, summarize the overall biomechanical and clinical outcomes, and assess whether the cumulative research supports the adoption of this technique compared with transosseous (TO) repair.

METHODS

A systematic literature review using the Preferred Reporting Items for Systematic and Meta-Analyses guidelines was performed. Multiple electronic databases were searched to identify studies focusing on surgical outcomes of patellar tendon repair with suture anchor usage. Cadaver and animal biomechanical studies, technical studies, and clinical studies were included.

RESULTS

A total of 29 studies met the inclusion criteria: 6 cadaver, 3 animal, 9 technical, and 11 clinical reports. Four of the 6 cadaver studies and 1 of the 2 animal studies found significantly less gap formation from SA than from TO repair. Average gap formation in human studies ranged from 0.9 to 4.1 mm in the SA group compared with 2.9 to 10.3 mm in TO groups. Load to failure was significantly stronger in 1 of 5 cadaver studies and 2 of 3 animal studies, with human studies SA load to failure ranging from 258 to 868 N and TO load to failure ranging from 287 to 763 N. There were 11 clinical studies that included 133 knees repaired using SA. Nine studies showed no difference between complication rate or risk for reoperation, where one study reported a significantly lower re-rupture rate after SA repair compared with TO repair.

CONCLUSIONS

SA repair is a viable option for patellar tendon repair and could have several advantages over TO repair. Multiple studies indicate that SA repair has less gap formation during biomechanical testing compared with TO repair in human cadaver and animal models. No differences in complications or revisions were found in the majority of clinical studies.

CLINICAL RELEVANCE

Both animal and human models suggest SA fixation has potential biomechanical benefits when compared with TO tunnels for patellar tendon repair, whereas clinical studies show no difference in complications and revisions postoperatively.

Patellar Sleeve Avulsion Fracture Repair: Suture Anchor Technique With Suture Cerclage Augmentation

Patella sleeve fractures are rare injuries that occur in pediatric patients. For minimally displaced fractures, nonoperative treatment with immobilization is possible. When fractures are displaced, surgical repair is indicated. Previously described operative techniques include transosseous sutures and tension band wiring. We describe a surgical technique to repair distal pole and patella sleeve avulsion fractures in pediatric patients using intraosseous suture anchors with suture cerclage augmentation.

Surgical treatment of inferior pole fractures of the patella: a systematic review

PURPOSE

This study aimed to comprehensively review the existing evidence concerning surgical treatment of inferior pole fractures of the patella and to report the outcomes and complications of different fixation techniques.

METHOD

This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Searches of PubMed, Scopus, and Web of Science were conducted in March 2023. Studies were screened against predecided inclusion and exclusion criteria. The extracted data included fracture characteristics, surgical techniques, and radiographic and functional outcomes. The Methodological Index for Non-Randomized Studies (MINORS) quality assessment tool was used to assess the eligible literature. The primary outcome was postoperative range of motion of different surgical methods, and the secondary outcomes were other clinical results and complications.

RESULTS

A total of 42 studies satisfied all the inclusion criteria and were deemed suitable for review. Fourteen case-control studies and 28 case series were selected, for a total of 1382 patients with a mean age of 51.0 years (range = 11-90). The follow-up period ranged from 6 to 300 months. The surgical techniques were categorized based on the device used as follows: (1) rigid fixation device; (2) tensile fixation device; (3) mixed device; and (4) extra-patella device.

CONCLUSION

Regarding the outcomes following surgical treatment of inferior pole fractures of the patella, the postoperative range of motion (ROM) of each technique ranged from 120° to 135°, with the exception of that involving the patellotibial wire which had poorer outcomes. The lowest functional score was also found in those using the patellotibial wire. Complications after surgery are rare, but approximately half of the patients required additional surgery for implant removal, particularly those whose initial surgery involved rigid fixation devices. It's worth noting that bony fragment excision is no longer recommended, and the combined use of multiple surgical devices is now more common.

Efficacy comparison of Kirschner-wire tension band combined with patellar cerclage and anchor-loop plate in treatment of inferior patellar pole fracture

Objective: This study aimed to compare the biomechanical stability and clinical efficacy of the Kirschner-wire (K-wire) tension band combined with patellar cerclage and an anchor-loop plate (ALP) in treating inferior-pole patellar fracture.

Methods: The finite element model was established to analyze the mechanical properties of a K-wire tension band combined with patellar cerclage and ALP fixation in the treatment of inferior patellar pole fracture. The clinical data of 49 patients with patellar inferior-pole fracture (AO/OTA 34 A1) admitted to our hospital from January 2017 to July 2021 were retrospectively analyzed. Among these, 28 cases were fixed with ALPs (ALP group) and 21 cases were fixed with K-wire tension bands combined with patellar cerclage (K-wire group). By reviewing the medical records and follow-up results, we compared the operation time, final knee joint activity, incidence of secondary surgery, postoperative complications, and joint function recovery between the two groups.

Results: The biomechanical analysis of the finite element model showed that the maximum displacement of the K-wire group was 1.87 times that of the ALP group. The maximum stress of the K-wire group was 1.34 times that of the ALP group. The maximum stress of the pole bone in the K-wire group was 13.89 times that of the ALP group. The average follow-up times of the K-wire group and ALP group were similar (p > 0.05), and the average ages of the two groups were similar (p > 0.05). The operation time of the ALP group was significantly shorter than that of the K-wire group (p < 0.05).The final knee joint activity of the ALP group was significantly greater than that of the K-wire group (p < 0.05). The Bostman patellar fracture function score of the ALP group was significantly better than that of the K-wire group at 3 and 9 months after operation (p < 0.05). Postoperative complications of the two groups included 1 case (3.6%) in the ALP group with internal fixation-stimulation complications and, in the K-wire group, 3 cases (14.3%) with internal fixation stimulation complications and 1 case (4.8%) with infection.

Conclusion: The ALP and K-wire tension band combined with patella cerclage models were tested at 500 N, and no damage occurred, indicating that the newly designed ALP is safe in mechanical structure. The ALP has better therapeutic effect in biomechanical stability, postoperative complications, secondary surgery, and knee function. This technique is an effective method for the treatment of inferior-pole patellar fracture.

Design and Validation of a Smile-Necklace Plate for Treating Inferior Patellar Pole Avulsion Fractures: A Review and Hypothesis

The patella's inferior pole transmits force generated by contraction of the quadriceps muscle to the tibial tuberosity through the attached patellar ligament, thus completing knee extension. Therefore, fractures of the patella's inferior pole disrupt the coherence of mechanical transmission in the lower extremities. There appears to be no consensus among trauma centers regarding the treatment of infrapatellar pole fractures, primarily because there is no consistent design or application of internal fixation for this type of fracture. We designed a new internal implant similar to the smile necklace based on our previous study. This smile‐necklace plate (SNP) has the advantage of both plate fixation and tension‐band wiring fixation, permitting early rehabilitation, especially in osteoporotic comminuted infrapatellar pole fractures. Finite element analysis helped verify the biomechanical advantages of the SNP in comparison with existing studies. Hence, this novel implant is a promising treatment option for inferior pole patellar fractures.