Open reduction and internal fixation of displaced patella inferior pole fractures with anterior tension band wiring through cannulated screws

Morphological characteristics and a new classification system of the inferior pole fracture of the patella: A computer-tomography-based study

PURPOSE

The objective of this study was to measure the morphological characteristics of inferior pole fracture of the patella (IPFP) and develop a practical classification system to determine the corresponding treatment protocols for different IPFPs with specific patterns.

METHODS

A retrospective radiographic review was performed on a series of 71 patients with IPFP. The preoperative CT data were collected and measured using image processing software. The number of fragments, maximum fracture fragment anteroposterior length (MFFAL), maximum fracture fragment transverse length (MFFTL), fracture fragment coronal angle (FFCA), fracture fragment sagittal angle (FFSA), maximum fracture fragment height (MFFH) and maximum transverse sectional area (MTSA) were analysed.

RESULTS

The mean number of fracture fragments was 3.8. The average MFFAL was 14.9 mm, the average MFFTL was 23.5 mm, the average FFCA was 92.1°, the average FFSA was 93.0°, the average MFFH was 13.6 mm, and the average MTSA was 299.3 mm2. A new classification system was introduced to describe the varied patterns of IPFP, summarized as (I) simple IPFP; (II) comminuted IPFP; (III) simple IPFP with simple patellar body fracture; and (IV) comminuted patellar fracture involving the inferior pole. With the four-type classification system, 12 type I, 22 type II, 21 type III, and 16 type IV lesions were observed, each with specific morphological characteristics.

CONCLUSION

Most IPFPs exhibited a diversiform pattern, demonstrating that coverage fixation was likely needed. The four-type classification system might offer a valuable approach to help orthopaedic surgeons make individual treatment plans.

Comparison of Fixation Methods Between Transosseous Pull-Out Suture and Separate Vertical Wiring for Inferior Pole Fracture of Patella: A Systematic Review and Meta-Analysis

OBJECTIVES

To compare, in a systematic review, Krakow transosseous (KT) suturing and separate vertical wiring (VW) fixation methods in inferior pole fractures of the patella and to evaluate whether the supplementary fixation affected bone union.

METHODS

DATA SOURCES

The MEDLINE, Embase, and Cochrane databases were searched from inception to January 15, 2023. The keywords were "patella inferior pole fracture", "patella distal pole fracture", "transosseous", "pull-out suture", "reattachment", and "vertical wiring".

STUDY SELECTION

All clinical studies describing KT or VW techniques for inferior pole fracture of the patella and reporting bone union-related complications were included.

DATA EXTRACTION

This meta-analysis included 16 studies with 274 patellae. Demographic data, surgical techniques, clinical outcomes, and complication rates were recorded. The Methodological Index for Non-Randomized Studies criteria were used to assess their quality.

DATA SYNTHESIS

A meta-analysis was performed using random-effects models and meta-regression. The meta-analytic estimate of bone union-related complications was 3.8% (95% CI, 1.6%-6.0%) for either PO or VW techniques in inferior pole fractures of the patella. The bone union-related complication rates did not differ significantly between the two techniques (KT, 5.7%; VW, 3.0%; P = .277). Meanwhile, supplementation fixation was significantly associated with decrease in bone union-related complication rates ( p = .013).

CONCLUSIONS

Fixation of inferior pole fractures of the patella using either KT or VW techniques provided satisfactory and similar clinical results with minimal bone union-related complications. Supplementary fixation has a positive impact on reducing bone union-related complications in inferior pole fractures of the patella following KT and VW techniques.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A novel technique of a new cannulated screw for treatment of inferior pole patellar fractures: a finite element study

OBJECTIVE

We invented a new cannulated screw with holes on the tail, which called Ding's screw. The goal of this study was to evaluate the biomechanical outcomes of this new screw with tension band wiring for the treatment of inferior pole patellar fractures in a finite element model.

METHODS

We conducted a finite element biomechanical study using two fixation methods: Ding's screw and tension band wiring (DSTBW) and cannulated screws and tension band wiring (CSTBW). Two methods were simulated to fix the inferior pole patellar fracture in a finite element model. The relative displacement and stress distribution were analyzed and compared.

RESULT

There were less displacement and stress distribution of DSTBW in different knee movement (30°, 60°, 90°, 120°) when compared to CSTBW. The highest value of displacement of the fracture and von Mises stress of the internal fixation happened in 120° knee movement in both groups. The highest displacement of the DSTBW was less than that of the CSTBW (1.92 mm to 2.12 mm). The highest value of the stress on the screws was 110.60 MPa in DSTBW group, and 132.90 MPa in CSTBW group. The highest value of the stress on the titanium cable was 38.51 MPa in DSTBW group, and 41.91 MPa in CSTBW group.

CONCLUSION

DSTBW fixation provides more stability than CSTBW fixation model in a finite element study.

Clinical outcome of rim-plate-augmented separate vertical wiring with supplementary fixation for the treatment of patellar fracture associated comminuted inferior pole

Despite the variety of treatment methods, comminuted inferior pole fractures of the patella remain difficult and technically demanding to achieve stable internal fixation. The purpose of this study is to evaluate the clinical outcomes of rim plate-augmented separate vertical wiring with supplementary fixation in the management of comminuted inferior pole fractures, AO/OTA 34-A1, C2, and C3, which has the secondary horizontal fracture line on lower articular boundary. From our study, bony union was achieved in all patients at an average of 3.1 ± 1.4 months after surgery. There was no patient with loss of reduction, fixation failure, or infection during follow-up. The average final range of motion was 131.6° ± 7.2°. Lysholm knee scores gradually increased over 3, 6, 9, and 12 months postoperatively by 58.7, 74.0, 82.9, and 89.4, respectively. Isokinetic peak torque deficit of the knee extensor muscles in 3, 6, 9, and 12 months postoperatively was 59.9%, 49.7%, 35.7%, and 28.1%, respectively. The rim plate-augmented separate vertical wiring with supplementary fixation for the treatment of patellar fracture associated comminuted inferior pole is effective and can be safely applied AO/OTA 34-C2 or C3 with favorable outcomes.

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.

The effect of Ding's screws and tension band wiring for treatment of inferior pole patellar fractures

OBJECTIVES

We developed a cannulated screw with holes in the tail, named the Ding's screw. The objective of this study was to evaluate the clinical effect of Ding's screw in the treatment of inferior pole patellar fracture.

METHODS

From March 2017 to October 2021, 68 patients with inferior pole patellar fracture in our department were retrospectively reviewed. According to different treatment methods, they were divided into Ding's screw and tension band wiring group (DSTBW) and cannulated screws and tension band wiring group (CSTBW). Radiological and clinical outcomes were evaluated and compared.

RESULTS

There were 33 cases in DSTBW group and 35 cases in CSTBW group. The mean follow-up duration was 14.5 ± 2.6 months in the DSTBW group and 15.0 ± 2.3 months in the CSTBW group. No significant differences in age, sex, operative side or time to surgery were present between the two groups. Skin breakdown and infection were not significantly different among the groups (P > 0.05). At the last follow-up, the average Bostman score of the DSTBW group was 28.5 ± 1.3(excellent) and that of the CSTBW group was 27.8 ± 1.6(good), with statistical significance (P = 0.045). The average Lysholm score of the DSTBW group was 94.1 ± 3.4 (good), and that of the CSTBW group was 90.1 ± 4.4 (good), and the difference was statistically significant (P < 0.001). The average knee joint ROM of the DSTBW group was 135.6 ± 6.8˚, and that of the CSTBW group was 130.1 ± 6.7˚, and the difference between the two groups was statistically significant (P = 0.001).

CONCLUSIONS

DSTBW is an effective method for the treatment of inferior pole patellar fractures with stable fixation and good functional effect.

Tension-band wiring through a single cannulated screw combined with suture anchors to treat inferior pole fracture of the patella

PURPOSE

To evaluate the feasibility and clinical outcomes of tension-band wiring through a single cannulated screw combined with two suture anchors in treating inferior pole fracture of the patella.

METHODS

Between September 2018 and September 2021, a total of 22 patients with a mean age of 55 years who sustained inferior pole fracture of the patella and were treated by tension-band wiring through a single cannulated screw combined with two suture anchors were enrolled. X-ray radiographs were performed to observe the bone union time. The duration of each operation was recorded to reflect the complexity of surgical treatment. Functional measurements, comprising range of motion (ROM), the Böstman scale, and the Knee Injury and Osteoarthritis Outcome Score (KOOS), were taken. Postoperative complications including fixation failure, incision infection, loss of reduction, and malunion were evaluated.

RESULTS

All patients were followed up for an average of 17 months (range: 12-25 months). The average clinical bone union time was 8 weeks (range: 6-12 weeks), and the radiographic bone union time was 11 weeks (range: 8-12 weeks). At the final follow-up, the mean ROM was 136° (range: 115°-140°), the KOOS was 85 (range: 68-100) and the Böstman score was 28 (range: 20-30); these outcomes were classified as excellent in 17 cases and good in 5 cases, with no instances of poor results. Loss of reduction occurred in one case, while no cases of incision infection, fixation failure or malunion were observed.

CONCLUSION

For inferior pole fracture of the patella, tension-band wiring through a single cannulated screw combined with suture anchors can offer sufficient fixation stability to achieve a satisfactory clinical outcome with reduced operational complexity; this procedure should be recommended in clinical practice.

Separate vertical wiring plus bilateral anchor girdle suturing fixation for the fractures of the inferior pole of the patella

BACKGROUND

The fixation of inferior pole fractures of the patella (IPFPs) is still a great challenge for surgeons.

MATERIALS AND METHODS

We introduced a new fixation method for IPFP fixation, that is, separate vertical wiring plus bilateral anchor girdle suturing fixation (SVW-BSAG). Three finite element models including the anterior tension band wiring (ATBW) model, separate vertical wiring (SVW) model and SVW-BSAG model, were built to evaluate the fixation strength of different fixation methods. A total of 41 consecutive patients with IPFP injury were enrolled in this retrospective study, including 23 patients in the ATBW group and 18 patients in the SVW-BSAG group. The operation time, radiation exposure, full weight-bearing time, Bostman score, extension lag versus contralateral healthy leg, Insall-Salvati ratio, and radiograph outcomes were employed to assess and compare the ATBW group and SVW-BSAG group.

RESULTS

The finite element analysis confirmed that the SVW-BSAG fixation method was as reliable as the ATBW fixation method in terms of fixed strength. Through retrospective analysis, we found that there was no significant difference between the SVW-BSAG and ATBW groups in age, sex, BMI, fracture side, fracture type, or follow-up time. There were no significant differences between the two groups in the Insall-Salvati ratio, 6-month Bostman score, and fixation failure. Compared with the ATBW group, the SVW-BSAG group showed advantages in intraoperative radiation exposure, full weight-bearing time, and extension lag versus the contralateral healthy leg.

CONCLUSION

The finite element analysis and clinical results showed that SVW-BSAG fixation methods are a reliable and valuable for IPFP treatment.

Management of comminuted inferior patellar pole fractures with cerclage-wire-augmented separate vertical wiring: a retrospective clinical study

PURPOSE

Comminuted inferior patellar pole fractures are challenging injuries and require effective treatment due to the extension mechanism of the knee. This study aims to evaluate the outcome of above fractures treated with a modified technique of cerclage-wire-augmented separate vertical wiring (SVW) with cerclage wiring passed through the proximal patella.

METHODS

Retrospective analysis (1/2017-1/2020) were performed for patients that were treated with three SVWs through the posterior margin of proximal fragment and directly to the anterosuperior border of patella, combined with a cerclage wiring passed through the proximal patella. Patients who experienced comminuted inferior patellar pole fractures within 3 weeks were included, and the outcome was evaluated radiologically and clinically by Bostman score after a minimum of 12 months following surgery. Further evaluation included the operation time and complication rate.

RESULTS

A total of 20 patients (10 males, 10 females) with a mean age of 54 ± 14.5 years (26-83 years) and a follow-up of 18.9 ± 6.6 months (12-36 months) were evaluated. The average operation time was 45.7 ± 8.8 min (30-60 min). At final follow-up, the average range of motion was 131.3° ± 3.5° (125°-135°), and the mean Bostman score was 29.4 ± 0.7 points (28-30) and graded excellent in all cases. Two patients experienced occasional giving way of the knee. Radiologically no loss of reduction, implant breakage, nonunion or skin irritation was observed.

CONCLUSIONS

The cerclage-wire-augmented SVW with cerclage wiring passed through the proximal patella appears to be a safe and simple technique which can effectively treat the comminuted inferior patellar pole fractures.

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.

Combination of Cable Cerclage and Hook Plate for the Fixation of Comminuted Fractures of Inferior Patellar Pole: A Review of 16 Consecutive Patients Followed Up for a Minimum of 1 Year

Objectives

To present a new method consisting of cable cerclage and hook plate for fixating the comminuted inferior patellar pole fracture and evaluate the outcomes.

Methods

A total of 16 consecutive patients who were treated with the construct of a cable cerclage in combination with a hook plate between January 2018 and September 2020 were included in the study. Mechanism of injury, duration, and technical details of the operation were reviewed. Plain radiographs and computerized tomography (CT) scans were routinely taken to evaluate the fracture pattern. The primary outcome measures included bony healing time, pain intensity‐numerical rating scale (PI‐NRS), range of motion (ROM), and the Bostman score at the final follow‐up.

Results

Eight males and eight females with an average age of 55.6 ± 12.0 years (range, 41 to 73 years) were included. Bony union was achieved in all the patients, with an average healing time of 10.8 ± 2.4 weeks (range, 8–16 weeks). With the average follow‐up of 20.1 ± 5.3 months, 12 patients (75%) had no pain (PI‐NRS score of 0), and the remaining four patients (25%) reported mild pain (three with a PI‐NRS score of 1 and one with a score of 2). The final Bostman score was 27.8 ± 3.0 (range, 20–30) on average, and all the patients showed excellent or good results. The average range of motion was 127.5° ± 13.9° (range, 90°–140°). No implant failure or hardware irritation was found during the follow‐up.

Conclusion

The fixation of cable cerclage combined with hook plate resulted as a reliable method for managing the inferior patellar pole fractures, allowing immediate rehabilitation and weight‐bearing.

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.

Triangular configuration with headless compression screws in the fixation of transverse patellar fracture

A triangular configuration with three parallel cannulated screws is an established treatment for fixing transverse patellar fractures; however, the stability achieved with this approach is slightly lower than that attained with cannulated screws combined with anterior wiring. In the present study, triangular configurations were modified by partially or totally replacing the cannulated screws with headless compression screws (HCSs). Through finite element simulation involving a model of distal femoral, patellar, and proximal tibial fractures, the mechanical stability levels of the modified triangular configurations were compared with that of two cannulated screws combined with anterior wiring. Four triangular screw configurations were developed: three HCSs in a forward and backward triangular configuration, two deep cannulated screws along with one superficial HCS, and two superficial cannulated screws with one deep HCS. Also considered were two parallel cannulated screws (inserted superficially or deeply) combined with anterior wiring. The six approaches were all examined in full knee extension and 45° flexion under physiological loading. The highest stability was obtained with the three HCSs in a backward triangular configuration, as indicated by the least fragment displacement and the smallest fracture gap size. In extension and flexion, this size was smaller than that observed under the use of two deeply placed parallel cannulated screws with anterior wiring by 50.3% (1.53 vs. 0.76 mm) and 43.2% (1.48 vs. 0.84 mm), respectively. Thus, the use of three HCSs in a backward triangular configuration is recommended for the fixation of transverse patellar fractures, especially without the use of anterior wiring.

Clinical Effect of Suture Anchor and Double-Pulley Technique in the Treatment of Inferior Patellar Fracture

Objective

To evaluate the efficacy of suture anchor combined with double-pulley technique for subpatellar comminuted fractures compared with wire vertical suture and Krachow in the treatment of subpatellar fractures.

Methods

Retrospectively selected 48 patients with subpatellar pole comminuted fracture admitted in our hospital from February 2013 to July 2019, 25 patients with double-pulley technique (group A), and 23 patients with vertical wire suture with Krachow suture. Patient age, gender, AT/OTA typing, injury mechanism, follow-up time, surgical time, bleeding volume, mean fracture healing time, and postoperative complications were recorded. The Insall-Salvati index immediately and 6 weeks after surgery. Bostman scores and knee activity were recorded at each follow-up, and month 12 was taken as the final result.

Results

Time of surgery in group A (46.52 min) was significantly shorter than in group B (76.30 min). Intraoperative bleeding in group 15.1 ml, B, group 15.9 ml. Both incisions healed in stage I, averaging clinical healing of patella fracture within 10 weeks. There was no significant difference in mean Bostman score and knee activity at month 12 (group A: 28.4, 124.8°; group B: 28.1, 125.7°). There was no significant statistical difference in the Insall-Salvati index immediately or 6 weeks between the two groups. Group B patients had two wire fractures, fracture healing and the wire removed one year after surgery, and the remaining patients had no complications such as internal fixation loosening, fracture, delayed healing, or nonhealing of fracture.

Conclusion

Compared with the treatment of subpatellar fracture with wire vertical suture and Krachow method, suture anchor with double-pulley technique has short operation time, reliable fixation, and less complications. Patients can have early functional exercise and good knee function recovery without secondary surgery. It can be considered as an alternative therapy for this fracture and deserves clinical adoption and promotion.

Suture anchor fixation of comminuted inferior pole patella fracture-novel technique: suture bridge anchor fixation technique

PURPOSE

Comminuted inferior pole fractures of the patella are notorious fractures where it is difficult to obtain rigid internal fixation by conventional tension band wiring. The purpose of this study is to evaluate the clinical and radiological outcomes of the suture bridge anchor fixation for these comminuted inferior pole fractures of the patella.

METHODS

From March 2012 to December 2018, suture bridge anchor fixation for the inferior pole comminuted fracture of the patella was performed in 22 patients. There were 21 patients of inferior pole comminuted fracture and 1 patient of lower periosteal sleeve avulsion fracture. Clinical outcomes including SF-36 score, Knee injury and osteoarthritis outcome score (KOOS) and post-operative range of motion were evaluated. In all patients, suture bridge anchor fixation was performed and, tension band wiring with K wire was added for large fragment fixation in two patients. We evaluated bony union, the patellar height using Insall-Salvati ratio and its complications.

RESULTS

Mean age was 46 ± 20 (15-82) years. Mean follow-up period was 25 ± 18 (11-74) months. In all patients, bony union was achieved at postoperative 4 months. At final follow-up, mean SF-36 score was 72 ± 15 (30-91) points and KOOS score was 66.7 ± 16 (43-97). The average range of motion was 134 ± 5 (125-140) degrees. As a complication, one patient developed a wound infection and subsequent osteomyelitis of inferior pole fracture fragment. Compared to the normal knee, the Insall-Salvati ratio of the injured knee averages 0.73 and this smaller ratio less than 0.8 meant patella baja.

CONCLUSIONS

In the comminuted inferior pole fractures of the patella, suture bridge anchor fixation showed good bony union and satisfactory clinical outcomes at the short-term follow-up and could be a satisfactory alternative treatment option. Even though suture bridge anchor fixation in these fractures caused decreased Insall-Salvati ratio (patella height), any patellofemoral pain and limited range of motion was not developed.

LEVEL OF EVIDENCE

Level IV.

Plate osteosynthesis in patellar fractures: a systematic review and meta-analysis

INTRODUCTION

To perform a systematic review and assess the indications, outcomes, complications, and union rates associated with plate osteosynthesis in patellar fractures compared to tension band wiring.

METHODS

The systematic search was conducted for articles in PubMed, Embase Biomedical, Cochrane central, and LILACS databases (date of inception to July 30, 2020). Articles were included if they were randomized control trials, cohort studies, case-control studies, and case series (with more than five cases), which focused on the clinical outcomes of patients with plate osteosynthesis as a treatment for fracture of the patella and had a minimum follow-up of 3 months. All studies were assessed according to their level of evidence, the number of patients, age of patients, fracture patterns described, complications of treatment, and results summarized. Meta-analysis could only be done for two parameters (complications and reoperations) due to the paucity of data and heterogeneity of studies' limited statistical analysis. The data are presented as a review table with the key points summarized.

RESULTS

Twenty studies (seven prospective and 13 retrospective articles) identified 533 patients with 534 fractures who had undergone plate osteosynthesis for fracture of the patella. The most common fracture treated with plate osteosynthesis was 34C.

CONCLUSION

Basket plate was most commonly used for inferior pole fractures, while mesh plates were for intra-articular patella fractures. Overall plating was associated with better clinical outcomes, fewer complication rates, and high union rates compared to tension band wiring for patella fractures.

Comparison of Functional and Radiological Outcomes of Transverse Patellar Fractures Fixed with Tension Band Fixation Using Cannulated Screws and Kirschner Wires: A Prospective Randomized Study

PURPOSE

To compare functional and radiological outcomes of transverse patella fractures treated with tension band wiring using either two 4.5 mm cannulated screws or Kirshner wire.

METHODS

This is a non-blinded prospective randomized study comprising of two groups (n = 30 each) with closed transverse patella fractures treated with tension band wiring using Kirschner wire (K wire group) and two 4.5 mm cannulated screws (CCS group). Outcomes measured were radiological union, Knee Society score, range of motion and post-operative complications.

RESULTS

The CCS group showed a statistically significant higher range of motion than K wire group for each follow up (p < 0.001 in flexion and p < 0.005 in extension). A statistically significant higher percentage of patients in the CCS group showed signs of union at 6th and 12th post-operative week (p = 0.001 and 0.011 respectively) but no difference at 24th post-operative week (p = 0.313). The rate of hardware complications was significantly higher in K wire group (p = 0.001). No significant difference was noted in in the Knee society score and post-operative complications between the groups.

CONCLUSION

This study concludes that the fixation of closed transverse patella fractures using two 4.5 mm cannulated screws is allows a faster rate of union, a better knee range of motion and lesser hardware complications as compared to Kirschner wires. However more studies with larger sample sizes and longer follow up are required.

Suture Anchor Versus Transosseous Tunnel Repair for Inferior Pole Patellar Fractures Treated With Partial Patellectomy and Tendon Advancement: A Biomechanical Study

Background:

Comminuted inferior pole patellar fractures can be treated in numerous ways. To date, there have been no studies comparing the biomechanical properties of transosseous tunnels versus suture anchor fixation for partial patellectomy and tendon advancement of inferior pole patellar fractures.

Hypothesis:

Suture anchor repair will result in less gapping at the repair site. We also hypothesize no difference in load to failure between the groups.

Study Design:

Controlled laboratory study.

Methods:

Ten cadaveric knee extensor mechanisms (5 matched pairs; patella and patellar tendon) were used to simulate a fracture of the extra-articular distal pole of the patella. The distal simulated fracture fragment was excised, and the patellar tendon was advanced and repaired with either transosseous bone tunnels through the patella or 2 single-loaded suture anchors preloaded with 1 suture per anchor. Load to failure and elongation from cycles 1 to 250 between 20 and 100 N of force were measured, and modes of failure were recorded. Statistical analysis was performed using a paired 2-tailed Student t test.

Results:

The suture anchor group had less gapping during cyclic loading as compared with the transosseous tunnel group (mean ± SD, 6.83 ± 2.23 vs 13.30 ± 5.74 mm; P = .047). There was no statistical difference in the load to failure between the groups. The most common mode of failure was at the suture-anchor interface in the suture anchor group (4 of 5) and at the knot proximally on the patella in the transosseous tunnel group (4 of 5).

Conclusion:

Suture anchors yielded similar strength profiles and less tendon gapping with cyclic loading when compared with transosseous tunnels in the treatment of comminuted distal pole of the patellar fractures managed with partial patellectomy and patellar tendon advancement.

Clinical Relevance:

Suture anchors may offer robust repair and earlier range of motion in the treatment of fractures of the distal pole of the patella. Clinical randomized controlled trials would help clinicians better understand the difference in repair techniques and confirm the translational efficacy in clinical practice.

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

Patellar inferior pole fracture is difficult to treat due to the inherent weakness of small comminuted distal fragments. However, suture fixation was recently introduced and reported. The aim of the present study was to evaluate and compare the clinical outcomes of two suture techniques, transosseous tunnel suture (TTS) and anchor suture (AS), for the fixation of patellar inferior pole fracture. A total of 35 patients with patellar inferior pole fracture treated at the Second Affiliated Hospital of Nanchang University (Nanchang, China) between June 2014 and April 2018 were retrospectively reviewed. Of these, 14 were treated with the TTS technique and 21 using AS fixation. The operation time, incision length and total cost were determined and compared. Functional outcomes were analyzed with the visual analog scale (VAS), Bostman and Lysholm scores and knee joint ranges of motion (ROMs). Postoperative complications were also observed and recorded. The mean follow-up was 22.6±9.7 and 18.7±5.9 months for TTS and AS, respectively. The groups were similar regarding age, sex, operative side and time to surgery. A smaller incision length and shorter operation time but higher hospital costs were observed in the AS group (P<0.01). For functional evaluation, there was no significant difference in VAS, Bostman and Lysholm scores or ROM between the 2 groups (P>0.05). No postoperative complications were observed in the TTS group. Only one patient in the AS group experienced a superficial minor wound infection. The TTS and AS techniques provided similarly satisfactory clinical outcomes for treating patellar inferior pole fracture. TTS had the advantage of cost-effectiveness due to saving anchors, while AS had a shorter operation time and a smaller incision length.

Fracture of the inferior pole of the patella: tension band wiring versus transosseous reattachment

BACKGROUND

The optimal surgical technique for the fixation of inferior pole patellar fracture remains controversial. The aims of this study were (1) to compare clinical and radiological outcomes following fixation of inferior pole patellar fracture by using tension band wire (TBW) and transosseous reattachment (TOR) without excision of the bony fragment and (2) to determine the risk factors for postoperative radiological loss of reduction.

METHODS

For this retrospective cohort study, consecutive patients with inferior pole patellar fracture between January 2010 and December 2017 were recruited. The patients were grouped according to their fixation method (TBW or TOR), and demographic data, clinical outcomes, and postoperative Insall-Salvati (IS) ratio were analyzed. Then, the patients were grouped according to radiological loss of reduction, the possible risk factors for loss of reduction were identified, and odds ratios were calculated.

RESULT

This study included 55 patients with inferior pole patellar fracture; 30 patients were treated using TBW and 25 were treated using TOR. Clinical failure occurred in two patients in the TBW group (7%) and three in the TOR group (12%). The rate of radiological loss of reduction was significant higher in the TOR group, whereas removal of implants was significantly more common in the TBW group. Patella baja was noted immediately after surgery in the TOR group, but the IS ratios of the two groups were similar after 3 months. Fracture displacement of more than 30 mm was the only independent risk factor for postoperative radiological loss of reduction.

CONCLUSION

For treating inferior pole patellar fracture, both TWB and TOR were effective and had a low clinical failure rate. In 60% of patients undergoing TBW fixation, however, additional surgery was required to remove the implants. Patella baja occurred immediately following TOR, but the patellar height was similar to that in the TBW group after 3 months. Surgeons should be aware of the high risk of postoperative radiological loss of reduction, especially when the fracture displacement is more than 30 mm.

Interventions for treating fractures of the patella in adults

BACKGROUND

Fractures of the patella (kneecap) account for around 1% of all human fractures. The treatment of these fractures can be surgical or conservative (such as immobilisation with a cast or brace). There are many different surgical and conservative interventions for treating fractures of the patella in adults. This is an update of a Cochrane Review first published in 2015.

OBJECTIVES

To assess the effects (benefits and harms) of interventions (surgical and conservative) for treating fractures of the patella in adults.

SEARCH METHODS

We searched CENTRAL (2020, Issue 1), MEDLINE, Embase, LILACS, trial registers and references lists of articles to January 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) or quasi-RCTs that evaluated any surgical or conservative intervention for treating adults with fractures of the patella. The primary outcomes were patient-rated knee function, knee pain and major adverse outcomes.

DATA COLLECTION AND ANALYSIS

At least two review authors independently selected eligible trials, assessed risk of bias and cross-checked data extraction. Where appropriate, we pooled results of comparable trials.

MAIN RESULTS

We included 11 small trials involving 564 adults (aged 16 to 76 years) with patella fractures. There were 340 men and 212 women; the gender of 12 participants was not reported. Seven trials were conducted in China and one each in Finland, Mexico, Pakistan and Turkey. All 11 trials compared different surgical interventions for patella fractures. All trials had design flaws, such as lack of assessor blinding, which put them at high risk of bias, potentially limiting the reliability of their findings. No trial reported on health-related quality of life, return to previous activity or cosmetic appearance. The trials tested one of seven comparisons. In the following, we report those of the main outcomes for which evidence was available for the three most important comparisons. Four trials (174 participants) compared percutaneous osteosynthesis versus open surgery. Very low-quality evidence means that we are uncertain of the findings of no clinically important difference between the two interventions in patient-rated knee function at 12 months (1 study, 50 participants) or in knee pain at intermediate-term follow-up at eight weeks to three months. Furthermore, very low-quality evidence means we are uncertain whether, compared with open surgery, percutaneous fixation surgery reduces the incidence of major adverse outcomes, such as loss of reduction and hardware complications, or results in better observer-rated knee function scores. Two trials (112 participants) compared cable pin system (open or percutaneous surgery) versus tension band technique. The very low-quality evidence means we are uncertain of the findings at one year in favour of the cable pin system of slightly better patient-rated knee function, fewer adverse events and slightly better observer-rated measures of knee function. There was very low-quality evidence of little clinically important between-group difference in knee pain at three months. Very low-quality evidence from two small trials (47 participants) means that we are uncertain of the findings of little difference between biodegradable versus metallic implants at two-year follow-up in the numbers of participants with occasional knee pain, incurring adverse events or with reduced knee motion. There was very low-quality and incomplete evidence from single trials for four other comparisons. This means we are uncertain of the results of one trial (28 participants) that compared patellectomy with advancement of vastus medialis obliquus surgery with simple patellectomy; of one quasi-RCT (56 participants) that compared a new intraoperative reduction technique compared with a standard technique; of one quasi-RCT (65 participants) that compared a modified tension band technique versus the conventional AO tension band wiring (TBW) technique; and of one trial (57 participants) that compared adjustable patella claws and absorbable suture versus Kirschner wire tension band.

AUTHORS' CONCLUSIONS

There is very limited evidence from nine RCTs and two quasi-RCTs on the relative effects of different surgical interventions for treating fractures of the patella in adults. There is no evidence from trials evaluating the relative effects of surgical versus conservative treatment or different types of conservative interventions. Given the very low-quality evidence, we are uncertain whether methods of percutaneous osteosynthesis give better results than conventional open surgery; whether cable pin system (open or percutaneous surgery) gives better results than the tension band technique; and whether biodegradable implants are better than metallic implants for displaced patellar fractures. Further randomised trials are needed, but, to optimise research effort, these should be preceded by research that aims to identify priority questions.

Novel Rim Plating Technique for Treatment of the Inferior Pole Fracture of the Patella

To aim of the present paper was to introduce a novel fixation technique for the treatment of inferior pole fracture of the patella. We performed a prospective observational study of consecutive cases of inferior pole fracture of the patella that were treated at our institution between January 2018 and June 2019. The patients include three men and one woman, with an average age of 47 years (range: 42–59 years). All patients were treated with the novel rim plating fixation technique for preserving the inferior pole of the patella. During the surgery, a 2.4 mm straight locking compression plate was contoured to adapt to the arc of the lower half of the patella as the rim plate. After reduction of the fracture, the rim plate was fixed to the proximal fragment of the patella through multiple locking screws, against the continuous pull of the patellar tendon. The rim plate encircles and constricts the inferior pole fragments, functioning as a compression and blocking construct. If necessary, an additional anterior tension band or mini locking plate can be used to further prevent anterior displacement of the inferior pole fragments. Under this rigid fixation, motion of the knee and full weight‐bearing were encouraged postoperatively. The patients were followed up monthly until 12 months after surgery. The time to achieve 90°pain‐free, full range of motion of the knee, and fracture healing, were recorded. Related complications were monitored, including infection, loss of reduction, fixation failure, anterior knee pain, and soft‐tissue irritation. The modified Cincinnati knee rating system was used for knee function assessment. The average operative time was 58.8 min (range: 52–63 min). The average blood loss was 59.8 mL (range: 45–71 mL). For all patients, pain‐free 90° range of motion was restored in 2–4 weeks, and the full range of motion was restored in 8–11 weeks. All patients achieved bone union in 6–9 weeks with no displacement of the fragments or breakage of the implant. No patient complained of anterior knee pain or soft‐tissue irritation. The modified Cincinnati score at 12‐month follow up demonstrated excellent outcomes in all four patients. The rim plating technique may be a feasible option for the treatment of the inferior pole fracture of the patella.

Role of an additional third screw in the fixation of transverse patellar fracture with two parallel cannulated screw and anterior wire

BACKGROUND

Two parallel cannulated screws along with an anterior wire to construct a tension band is a popular approach in transverse patellar fractures. However, the optimal screw proximity, either deep or superficial screw placements, remains controversial. Hence, a new concept of the addition of a third screw to form a triangular configuration along with the original two parallel screws was proposed in this study. Therefore, the biomechanical effect of the additional third screw on the stability of the fractured patella was investigated with finite element (FE) simulation.

METHODS

An FE knee model including the distal femur, proximal tibia, and fractured patella (type AT/OTA 34-C) was developed in this study. Four different screw configurations, including two parallel cannulated screws with superficial (5-mm proximity) and deep (10-mm proximity) placements and two parallel superficial screws plus a third deep screw, and two parallel deep screws plus a third superficial screw, with or without the anterior wire, were considered for the simulation.

RESULTS

Results indicated that the addition of a third screw increased stability by reducing the dorsal gap opening when two parallel screws were deeply placed, particularly on the fractured patella without an anterior wire. However, the third screw was of little value when two parallel screws were superficially placed. In the existence of two deep parallel screws and the anterior wire, the third screw reduced the gap opening by 23.5% (from 1.15 mm to 0.88 mm) and 53.6% (from 1.21 mm to 0.61 mm) in knee flexion 45° and full extension, respectively. Furthermore, in the absence of the anterior wire, the third screw reduced the gap opening by 73.5% (from 2 mm to 0.53 mm) and 72.2% (from 1.33 mm to 0.37 mm) in knee flexion 45° and full extension, respectively.

CONCLUSION

Based on the results, a third cannulated screw superficially placed (5-mm proximity) is recommended to increase stability and maintain contact of the fractured patella, fixed with two parallel cannulated screws deeply placed (10-mm proximity), particularly when an anterior wire was not used. Furthermore, the third screw deeply placed is not recommended in a fractured patella with two parallel superficial screws.

Minimally invasive osteosynthesis technique in the treatment of transverse patellar fractures in the elderly

BACKGROUND

This prospective study aims to describe our experience in the management of transverse patellar fractures in elderly patients with minimally invasive osteosynthesis technique (MIOT), at 12-months follow-up.

METHODS

Patients older than 60, with transverse patellar fracture, type 34-C1 according to the AO/OTA classification system, referred to our trauma centre, between January 2014 and December 2017 were prospectively recruited. All the patients were managed using MIOT surgical procedure and underwent a clinical and radiological follow-up at 2 weeks, 6 weeks and at 3, 6, 12 and 15 months postoperatively. The clinical evaluation was performed using the Lysholm Knee Scoring System (LKSS) and the Visual Analogue Scale (VAS) for pain. The hardware removal was planned at 12-months follow-up. The paired t-test was performed. The test was two-tailed with a confidence level of 5%.

RESULTS

61 patients were recruited. The mean VAS was significantly lower in MIOT group until the 3-months follow-up (p = 0.001). ROM in flexion and LKSS score were significantly better in MIOT-group at all follow-ups, whereas ROM in extension showed no differences, between the two groups, starting from the 6-months follow-up. In the open surgery group, a significantly higher rate of delayed wound healing (p = 0.014), broken wires (p = 0.001) and non-cosmetic scar (p = 0.0221) was observed.

CONCLUSIONS

This prospective study shows that MIOT is a safe option for treatment of patellar transverse fractures in elderly patients, since it reduces the intra-operative blood loss, shortens the operating time, and is endowed with lower rates of postoperative complications.

The modified anterior ellipsoidal cap titanium cable tension band for comminuted patellar fractures

PURPOSE

The purpose of this study was to assess the outcomes in a series of patients, who underwent cerclage and figure-of-eight tension band wiring using a single titanium cable for comminuted patellar fractures.

METHODS

We describe a modified tension band technique using a single titanium cable to create an ellipsoidal cap structure that combines the circumferential and figure-of-eight wrapping in the fixation of closed Association for the Study of Internal Fixation/Orthopaedic Trauma Association 34C2 and 34C3 patellar fractures. We retrospectively reviewed 25 patients (16 males and 9 females, mean age 54 years) who underwent the described fixation technique between 2015 and 2017. Postoperative function was evaluated using the Böstman score.

RESULTS

At the mean follow-up of 25 months (range 17-39 months), the mean Böstman score was 27.3 ± 2.6 points (range 23-30). Eighteen patients (72%) had excellent results (score ≥28); seven patients (28%) had good results (score 20-27); and no patients had an unsatisfactory result (score < 20). All surgical incisions healed without major wound complications. Two patients reported minor complications (soft tissue irritation, cellulitis). No patients demonstrated loss of reduction or implant failure during the follow-up period.

CONCLUSION

The modified anterior ellipsoidal cap tension band using a single titanium cable created an effective tension band structure in the treatment of comminuted patella fractures. It is a simple operative technique that produced a stable fixation construct, which allowed early functional rehabilitation and weight-bearing with a high rate of excellent outcomes at 2 years after surgery.

Combination of a miniplate with tension band wiring for inferior patellar pole avulsion fractures

BACKGROUND

The tension-band technique, with Kirschner wires or cannulated screws, is one of the most commonly used fixation techniques for patellar fractures. However, it may be not useful for inferior patellar pole fractures as it may lead to fragment reduction loss and fixation failure. We present a surgical technique that combines a miniplate with tension band wiring for inferior patellar pole avulsion fractures and report surgical outcomes.

PATIENTS AND METHODS

Between June 2012 and May 2016, 17 consecutive patients (mean age: 51 years) with inferior patellar pole fractures (AO/OTA 34-A1) were treated operatively with a miniature plate in combination with tension band wiring. The final range of motion, bone union time, and Bostman score were the primary outcome measures.

RESULTS

The bone union time was 9.5 weeks on average after surgery (range: 8-12 weeks). No patient had loss of reduction or implant failure. There were no cases of irritation or other complications from the implant. At the final follow-up, the average range of motion arc was 128.24° (range: 105-140°). The mean Bostman score at the last follow-up was 28.1 points (range: 25-30 points). All patients showed excellent or good results 1 year after surgery.

CONCLUSION

The combination of a miniplate with tension band wiring for inferior patellar pole avulsion fractures provides stable flexion, allows for early range of motion, and provides excellent results in terms of knee function.

Comparison of a Novel Tension Band and Patellotibial Tubercle Cerclage in the Treatment of Comminuted Fractures of Inferior Pole of the Patella

Objective

To assess the therapeutic effect of a novel tension band using 3.0 mm cannulated screw combined with a titanium cable and specific shims comparatively with patellotibial tubercle cerclage in comminuted fractures of the inferior pole of the patella.

Methods

The retrospective study from March 2012 to July 2017 was conducted in Peking University Third Hospital and comprised 63 patients with comminuted fractures of the inferior pole of the patella: 41 treated with new tension band using 3.0 mm cannulated screw combined with a titanium cable and specific shims (new tension band group) and 22 with patellotibial tubercle cerclage (tubercle cerclage group). Gender, age, AO/OTA fracture type, injury mechanism, inter‐fragmentary gap, and follow‐up time of patients were recorded. Two groups were compared regarding: operation time, blood loss, partial weight‐bearing time, fracture‐healed time, Bostman score and knee mobility at 12‐month follow‐up, and postoperative complications. Continuous and categorical parameters were analyzed by Mann‐Whitney U test and the chi‐squared test, respectively. Fisher's exact test was used for small data subsets.

Results

Between the two groups, no statistically significant difference was found in mean age, gender, AO/OTA fracture type, injury mechanism, mean inter‐fragmentary gap, or mean follow‐up time (P > 0.05). The mean operation time of new tension band group was significantly longer than that of tubercle cerclage group (76.4 min vs 64.2 min, P = 0.006), while there was no significant difference in blood loss. After surgery, new tension band group had a significantly earlier mean partial weight‐bearing time (5.2 weeks vs 7.4 weeks, P < 0.001) and fracture‐healed time (9.6 weeks vs 11.6 weeks, P < 0.001). At 12‐month follow‐up, patients of new tension band group had a significantly higher mean Bostman score (28.5 vs 25.8, P < 0.001) and knee mobility (126.7 vs 117.3, P < 0.001). Ten complications related with internal fixation were found in tubercle cerclage group including two cases of loose internal fixation, two cases of cerclage breakage, and six cases of low patella position who undertook secondary operation. No complications were found in new tension band group (0 in 41 vs 10 in 22, P < 0.001).

Conclusion

Patients with comminuted fractures of the inferior pole of the patella treated with a novel tension band experienced a longer operation time, but earlier partial‐weight‐bearing and fracture‐healed time, better clinical outcomes at 12‐month follow‐up, and less complications. It should be considered an alternative therapy for the treatment of distal pole patellar fractures.

Management of comminuted patellar fracture fixation using modified cerclage wiring

Background

Although there are several different kinds of fixation techniques for displaced comminuted patellar fracture, the treatment remains a challenge for orthopaedic surgeons. The purpose of this study is to evaluate the effectiveness and safety of a fixation technique for comminuted patellar fracture fixation using modified cerclage wiring.

Methods

From February 2016 to April 2018, 38 cases of simple unilateral closed comminuted patellar fracture were treated by modified cerclage wiring. Among these cases, 16 patients were males and 22 were females, aged 23–68 years (average 40.4 ± 9.1 years). Comminuted patellar fractures were classified according to the AO/OTA classification: 10 cases were type 34-C2 (three fragments), 28 cases were type 34-C3 (more than three fragments). Postoperative complications including loosening of internal fixation, fragment re-displacement, nonunion, infection, breakage of internal fixation and traumatic osteoarthritis were assessed. The clinical results after operation were evaluated by the clinical grading scales of Böstman including range of movement, pain, work, atrophy, assistance in walking, effusion, giving way, and stair-climbing during follow-up.

Results

A total of 38 patients were followed up for 6–36 months (mean time 16.1 ± 5.8 months). The bone union radiographically occurred at approximately 2.5–3.5 months (mean time 2.92 ± 0.25 months). No postoperative complications, such as infection, dislocation, breakage of the implants, painful hardware, and post-traumatic osteoarthritis, were observed. According to the clinical grading scales of Böstman, satisfactory results were obtained, and the mean score at the final follow-up was 28.7 (range 20–30) points. Thirty-two patients (84.2%) with excellent results had a mean score of 29.5 ± 0.7 (range 28–30) points, and six patients (15.8%) with good results had a mean score of 24.5 ± 2.2 (range 20–27) points. The patients with excellent and good scores had active flexion of 130° (110–140).

Conclusions

Modified cerclage wiring can effectively treat comminuted patellar fracture and offers a new strategy resulting in satisfactory results without obvious complications.

Role of screw proximity in the fixation of transverse patellar fractures with screws and a wire

PURPOSE

Clinical and biomechanical studies have reported that using supportive screws and a wire instead of the common Kirschner wires for modified tension band wiring improves the stability of fractured patellae. However, the effect of screw proximity on the fixation of a fractured patella remains unclear. Therefore a numerical study was conducted to examine the effects of screw proximity on biomechanical responses in a simulated patellar fracture fixed using two parallel cannulated screws and anterior tension band wiring.

METHODS

A patellar model with a transverse fracture and loads simulating patellar tendon forces applied on the patella were used in the present simulation. The surgical fixation consisted of two 4.0-mm parallel partially threaded cannulated screws with a figure-of-eight tension band made using a 1.25-mm stainless steel wire. Biomechanical responses at two screw proximities, 5 and 10 mm from the leading edge of the patella, were investigated.

RESULTS

Superficial screw placement (5 mm) yielded higher stability, lower wire loads, and lower bone contact pressures than the deep placement (10 mm). The deep placement of screws exerted a higher load on the wire but a lower force on the screw than superficial placement did.

CONCLUSION

This is the first numerical study to examine the effects of screw location on the fixation of a fractured patella using cannulated screws and tension band wiring. Considering the favorable biomechanical responses, superficial placement (5 mm below the leading edge of the patella) is recommended for screw insertion when treating a transverse fractured patella.

A Locked Intraosseous Nail for Transverse Patellar Fractures: A Biomechanical Comparison with Tension Band Wiring Through Cannulated Screws

BACKGROUND

Displaced transverse patellar fractures require open reduction and internal fixation. State-of-the-art stabilization techniques are tension band wiring (TBW) using Kirschner wires or cannulated screws. These techniques are associated with high rates of secondary fracture displacement, implant migration, implant prominence, wound-healing disturbances, and the need for implant removal. Recently, a locked intraosseous patellar nail prototype was developed. The aim of the present study was to investigate the biomechanical performance of this nail compared with TBW using cannulated screws.

METHODS

Seven paired fresh-frozen human cadaveric knees were stripped of all soft tissues except the extensor apparatus. A transverse osteotomy was created to simulate an OTA/AO type 34-C1 transverse patellar fracture. The specimen pairs were randomly assigned to be fixed with TBW using cannulated screws or with the new intraosseous nail. Each specimen was cyclically tested for 5,000 cycles by pulling on the quadriceps tendon and simulating active knee extension and passive knee flexion within the range from 90° of flexion to full knee extension. Anterior and articular margin displacement of the fracture as well as interfragmentary rotation around the mediolateral axis were investigated with optical motion tracking after 100, 500, 1,000, 2,500, and 5,000 test cycles.

RESULTS

Within the respective 5 testing-cycle time points evaluated, the articular margin displaced on average 68%, 60%, 72%, 76%, and 81% less after intraosseous nailing compared with TBW. Whereas the difference remained nonsignificant after 100 and 500 cycles (p ≥ 0.116), a trend toward significance was observed after 1,000 cycles (p = 0.063), which became significant after 2,500 and 5,000 cycles (p ≤ 0.043).

CONCLUSIONS

From a biomechanical point of view, the locked intraosseous patellar nail may be an alternative to TBW using cannulated screws because of the higher interfragmentary stability provided at the articular fracture site.

CLINICAL RELEVANCE

A locked patellar nail for transverse patellar fractures achieved a stable osteosynthetic construct that may reduce hardware-associated complications because of its intraosseous positioning.

Modified Technique of Separate Vertical Wiring for the Fixation of Patellar Inferior Pole Fracture

To evaluate the biomechanical and clinical results of modified separate vertical wiring technique (SVW) for inferior pole patellar fracture repair we conducted a finite element biomechanical study using 2 fixation methods and evaluated a clinical series of eleven patients. The modified SVW technique was an effective, safe and simple method that can provide stable fixation for early exercise with excellent functional results in fixing inferior pole patella fractures.

Management of displaced inferior patellar pole fractures with modified tension band technique combined with cable cerclage using Cable Grip System

INTRODUCTION

We present a modified tension band technique combined with cable cerclage using Cable Grip System for the treatment of displaced inferior patellar pole fractures and report the knee functional outcome.

PATIENTS AND METHODS

The patients who had had operative treatment of a displaced inferior patellar pole fracture (AO/OTA 34-A1) between December 2013 and December 2015 were studied retrospectively. Eleven consecutive patients had had open reduction and internal fixation with the modified technique using Cable Grip System, of whom, five males and six females with an average age of 60.9 years (range, 29-81 years). All fractures occurred from direct fall onto the knee. The average time from injury to surgery was 6.1days (range, 2-12days). The range of motion (ROM) was measured in degrees by goniometry at postoperative intervals of 1, 2, 4, 12, and 48 weeks; Knee function was evaluated using the Rasmussen scores at final follow-up.

RESULTS

No patients had nonunion, loss of reduction, migration of wire, irritation from the implant and fixation breakage during the follow-up period. Recovery of ROM was achieved at 12 weeks, with the average ROM at 1 week was 72° (range, 65°-78°), 86.4° (range, 78°-92°) at 2 weeks, 115.5° (range, 103°-122°) at 4 weeks, 129.6° (range, 122°-133°) at 12 weeks, 134.5° (range, 129°-139°) at 48 weeks after the operation. Concerning the knee function outcome assessment, all patients showed excellent results at final follow-up. The average Rasmussen scores was 27.9 out of 30 (range, 27-29).

CONCLUSIONS

The modified tension band technique combined with cable cerclage using Cable Grip System for displaced inferior patellar pole fractures can provide stable fixation with excellent results in knee function, allows for immediate mobilization and early weight-bearing, which is a simple and valuable technique in routine clinical practice.

Biomechanical evaluation of the tension band wiring principle. A comparison between two different techniques for transverse patella fracture fixation

PURPOSE

The aim of this study was to investigate the validity of the dynamic compression principle of tension band wiring in two techniques for patella fracture treatment.

METHODS

Twelve human cadaveric knees with simulated transverse patella fractures were assigned to two groups for treatment with tension band wiring using either Kirschner (K-) wires or cannulated screws. Biomechanical testing was performed over three knee movement cycles between 90° flexion and 0° full extension. Pressure distribution in the fracture gap and fracture site displacement were evaluated at the 3^rd cycle in 15° steps, namely 90°-75°-60°-45°-30°-15°-0° extension phase and 0°-15°-30°-45°-60°-75°-90° flexion phase.

RESULTS

Mean anterior / posterior interfragmentary pressure in the groups with K-wires and cannulated screws ranged within 0.16-0.40MPa / 0.12-0.35MPa and 0.37-0.59MPa / 0.10-0.30MPa, respectively. These changes remained non-significant for both groups and loading phases (P≥0.171). Mean anterior / posterior fracture site displacement for K-wires and cannulated screws ranged within -0.01-0.53mm / 0.11-0.74mm and 0.11-0.55mm / -0.10-0.50mm, respectively. Anterior displacement remained without significant changes for both groups and loading phases (P≥0.112). However, posterior displacement underwent a significant increase in the course of knee extension for K-wires (P≤0.047), but not for cannulated screws (P≥0.202). Significantly smaller displacement at the posterior fracture site was detected in the group with cannulated screws compared to K-wires at 60° and 75° extension phase (P≤0.017), as well as at 45°, 60° and 75° flexion phase (P≤0.018). The critical value of 2mm displacement at the posterior fracture site was not reached for any specimen and fixation technique. Knee extension was accompanied by synchronous increase in quadriceps pulling force.

CONCLUSIONS

Tension band wiring fulfills from a biomechanical perspective the requirements for sufficient stability of transverse patella fracture fixation. It should, however, rather be considered as a static fixation principle than a dynamic one. Tension band wiring with cannulated screws was found advantageous over Kirschner wires in terms of interfragmentary movements at the posterior fracture site.

Revisiting Tension Band Fixation for Difficult Patellar Fractures

Patella fractures with comminution, osteoporotic bone, and/or previously failed fixation are exceedingly difficult to reduce and fix. Moreover, the risk of symptomatic constructs and patients who are poorly compliant with postoperative activity restrictions can make these complex fracture patterns an even more challenging scenario. Although there is an array of techniques described for comminuted patella fractures, there lacks an accepted surgical technique for these difficult cases. In this clinical series, we describe an enhancement to the traditional tension band construct that uses additional wires and multiple tension bands to gather and fix comminuted fracture patterns in nontransverse planes, bolster osteoporotic bone, and secure fractures in patients undergoing a revision and/or have potential to be poorly compliant with postoperative activity restrictions. The clinical outcomes of 27 patients demonstrate high rates of bony union, functional range of motion, and low rates of both infection and failure. In conclusion, using the basic principles of tension band wiring remains highly versatile, useful, and economical in approaching difficult patella fractures.

Internal Fixation of Transverse Patella Fractures Using Cannulated Cancellous Screws with Anterior Tension Band Wiring

Aims: To evaluate the effectiveness and safety of anterior tension band wiring technique using two cannulated cancellous screws in patients with transverse (AO34-C1) or transverse with mildly comminuted (AO34-C2) patellar fractures.

Materials and Methods: This is a prospective study of 25 patients with transverse fracture or transverse fracture with mildly comminuted patella fractures. All the patients were treated with open reduction and internal fixation using two parallel cannulated screws and 18G stainless steel wire as per the tension band principle.

Results: There were eighteen males (72%) and seven females (28%). The age group ranged from 24 to 58 years, with mean age of 38 years. The most common mode of injury was fall (72%) followed by road traffic accident (20%) and violent quadriceps contraction (8%). Transverse fracture was present in 60% and transverse fracture with mild comminution in 40% of patients. Mean time to achieve union was 10.7 weeks (range 8-12 weeks). Mean ROM at three months was 113.8 degree (90-130) and at final follow up this improved to 125.4 degrees (range 100-140). There was one case of knee stiffness and no case of implant failure was observed. Patients were evaluated using Bostman scoring, the mean score at three months being 26.04 which improved to 27.36 at the end of final follow up at one year.

Conclusion: Cannulated cancellous screws with anterior tension band wiring is a safe, reliable and reproducible method in management of transverse patellar fractures, with less chances of implant failure and soft tissue irritation.

Internal fixation of displaced inferior pole of the patella fractures using vertical wiring augmented with Krachow suturing

BACKGROUND

We present the surgical technique of separate vertical wiring for displaced inferior pole fractures of the patella combined with Krachow suture and report the surgical outcomes.

MATERIALS AND METHODS

Between September 2007 to May 2012, 11 consecutive patients (mean age, 54.6 years) with inferior pole fractures of the patella (AO/OTA 34-A1) were retrospectively enrolled in this study. Through longitudinal incision, all patients underwent open reduction and internal fixation by separate vertical wiring combined with Krackow suture. The range of motion, loss of fixation, and Bostman score were primary outcome measures.

RESULTS

The union time was 10 weeks after surgery on average (range: 8-12). No patient had nonunion, loss of reduction and wire breakage. There was no case of wound problem and irritation from the implant. At final follow-up, the average range of motion arc was 129.4° (range: 120-140). The mean Bostman score at last follow-up was 29.6 points (range: 28-30) and graded excellent in all cases.

CONCLUSION

Separate vertical wiring combined with Krackow suture for inferior pole fractures of the patella is a useful technique that is easy to perform and can provide stable fixation with excellent results in knee function.

Internal fixation of patellar apex fractures with the basket plate: 25 years of experience

INTRODUCTION

Comminution of the patellar apex is amenable to internal fixation by standard techniques and usually requires partial patellectomy. In our institution, multifragmentary fractures of the distal pole are treated with the basket plate, which is shaped to fit the geometry of the patellar apex. This implant has been used in our institution for over 25 years. The aim of this study was to evaluate long-term results of internal fixation of comminuted fractures of the patellar apex with the basket plate.

MATERIALS AND METHODS

A total of 142 patients with fracture of the distal pole of the patella were treated with the basket plate between 1988 and 2013. Functional evaluation was conducted using the modified Cincinnati knee rating system. A total of 98 patients were available for late functional evaluation.

RESULTS

There were no infections or implant-related problems during the follow-up period. All fractures healed within 8 to 10 weeks. There were three cases of early revision because of improper use of the implant and incorrect indication. Functional outcome following internal fixation with the basket plate was excellent in 80 patients and good in 18; there were no poor results.

CONCLUSION

Internal fixation with the basket plate is recommended for management of multifragmentary fractures of the patellar apex because this method enables early, unrestricted knee motion, and provides reliable healing and good functional outcome. This method is an alternative to partial patellectomy and is considered a patella-saving procedure; therefore, the use of the basket plate is strongly recommended for the treatment of distal pole fractures.

Comparison of the outcomes of cannulated screws vs. modified tension band wiring fixation techniques in the management of mildly displaced patellar fractures

BACKGROUND

K wire fixation with tension band wiring has conventionally been used for the open reduction and internal fixation of the patella. However, it suffers from distinct disadvantages such as implant irritation, need for open reduction, incidence of palpable implants, and need for subsequent implant removal. A smaller incision with percutaneous fixation may be an alternative to this established conventional technique. Thus, the purpose of this trial was to compare the treatment outcomes of patients with mildly displaced patellar fractures treated with closed reduction and percutaneous cannulated screw fixation (CRCF) as compared to open reduction and tension band wiring fixation (ORTF). Specifically, we aimed to determine whether cannulated screw fixation was associated with improved clinical outcomes at 12 months as measured using the Lysholm score, pain scores, degree of flexion, range of motion, time to radiographic union, radiographic outcomes, and complication rates.

METHODS

Sixty-three patients with transverse patellar fractures displaced less than 8 mm were included in this prospective, randomized, controlled trial, with 52 patients in the final data analysis. Thirty-two patients were operatively treated by CRCF with either two or three cannulated screws. Thirty-one patients were operatively treated by conventional ORTF using the modified tension band technique. At postoperative intervals of 3, 6, and 12 months, knee function was evaluated using the Lysholm score, pain was assessed using the visual analog scale (VAS) score, and active knee extensions and flexion were measured in degrees by goniometry.

RESULTS

The CRCF group had average Lysholm scores of 84.4 ± 5.8, 86.7 ± 6.4, and 93.2 ± 5.3 after 3, 6, and 12 months, respectively, which were significantly greater than those of the ORTF group (79.0 ± 5.3, p = 0.001; 81.5 ± 4.6, p = 0.002; and 89.8 ± 6.2, p = 0.039, respectively). Lower pain and squatting scores were the main reasons for the poorer Lysholm scores in the ORTF group. The VAS scores showed that the CRCF group had lower pain scores and better flexion and total range of motion (ROM) compared with the ORTF group after 3 and 6 months, although both groups had similar outcomes after 12 months. The mean fracture healing time of 2.65 months was similar in the CRCF groups (2.77 months; p = 0.440). Complication rates were 3/26 (11.5 %) in the CRCF group and 14/26 (53.4 %) in the ORTF group. Two patients in the CRCF group and eight patients in the ORTF group experienced skin irritation. In addition, two (7.7 %) patients in the CRCF group and 11 (42.3 %) patients in the ORTF group required implant removal because of symptoms due to the presence of the implants.

CONCLUSION

Surgical treatment of mild displaced (less than 8 mm) transverse patellar fractures by the CRCF technique provides satisfactory clinical results and excellent knee function, with little pain and a low incidence of complications at early follow-up (up to 6 months). These results suggest that the CRCF technique may be a superior alternative to conventional ORTF. Registration Trial (Chinese Clinical Trial Register): Current Controlled Trials ChiCTR-PRCH-14005017, registration dates 2014-06-14.

Patellar Fractures

Purpose. To describe a new surgical procedure and its outcomes: osteosynthesis with high-resistance sutures, avoiding metallic implants. Open sky osteosynthesis with Kirschner and cerclage wiring is the current gold standard for patella fractures. Favorable functional outcomes have been observed, although implant removal is required in many cases due to the prominent wires under the skin. New implants have been sought after to minimize the need for second surgeries. Methods. Eight patients, aged between 25 and 61 years, with a minimum follow-up of 24 months, were included in the present study. The surgical procedure consists of open reduction followed by internal fixation performing 3 longitudinal tunnels crossing double high-resistance sutures within these tunnels and suturing among them. Next, an anterior cerclage with parenchymal suture was performed. Results. During follow-up, no secondary fracture displacement was observed. No patient required or requested implant removal. Functional outcomes were equitable to other surgical techniques. Conclusion. Despite the relatively small number of patients, osteosynthesis with high-resistance suture presents as an acceptable alternative within patella fracture treatment, being safe and with similar functional outcomes when compared with other techniques. Furthermore, no second surgeries for implant removal were required during the present study.

Anchor suture fixation of distal pole fractures of patella: twenty seven cases and comparison to partial patellectomy

PURPOSE

Partial patellectomy (PP) and reattachment of the patellar ligament with transosseous suturing is the mainstay of surgical treatment for distal pole patellar fractures. An anchor suturing (AS) technique has recently been reported as an alternative to PP in such fractures and allows for bone-to-bone interface and possibly superior fracture healing than bone-to-tendon interface with PP. We present our experience with AS and compare it to PP.

METHODS

Between 2006 and 2011, 60 patients with distal pole patellar fracture underwent either AS (n = 27) or PP (n = 33). We retrospectively gathered their demographic data and information on fracture type, fixation technique, operation time, postoperative complications and knee range of motion. A telephone survey was performed to grade functional outcomes with standard questionnaires (the SF-12 for quality of life, the Kujala score for patellofemoral function and a visual analog scale [VAS] pain score).

RESULTS

AS was equivalent to PP in terms of residual pain and functional outcomes (VAS: 2.45 vs. 2.26, p = 0.83 and Kujala score: 74.3 vs. 69, p = 0.351, respectively) as well as for knee range of motion. Complications included three cases of infection in each group, two cases of early hardware failure and one case of non-union in the AS group. Operation time was significantly shorter for AS compared to PP (68.5 vs. 79.1 min, p = 0.03).

CONCLUSIONS

AS is non-inferior to PP for function and pain after distal pole patellar fractures and is superior to PP with regard to operative time. Common complications of this technique are hardware failure and infections.

LEVEL OF EVIDENCE

Therapeutic Level III.

Biomechanical evaluation of internal fixation techniques for unstable meso-type os acromiale

BACKGROUND

Several internal fixation surgical techniques have been described for the treatment of symptomatic os acromiale. The purpose of this study was to compare the biomechanical characteristics of different internal fixation techniques for the operative treatment of unstable meso-type os acromiale in a cadaveric model.

METHODS

Testing was performed on 12 matched pairs of cadaveric acromia with simulated meso-type os acromiale. Twelve specimens were prepared with 2 cannulated 4.0-mm screws only (SO group), inserted in the anterior-posterior direction. Contralateral specimens were repaired with screws and a tension band (TB group). An inferiorly directed load to the anterior acromion was applied at a rate of 60 mm/min until failure. Ultimate failure load, stiffness, and fracture pattern were recorded and analyzed.

RESULTS

Ultimate failure load was significantly higher for the TB group (mean, 336 N ± 126 N; range, 166-623 N; P = .01) than for the SO group (mean, 242 N ± 57 N; range, 186-365 N). In contrast, no significant difference in stiffness was found between the SO group (mean, 22.1 N/mm ± 4.7 N/mm; range, 13.0-33.3 N/mm; P = .94)) and the TB group (mean, 22.2 N/mm ± 2.9 N/mm; range, 18.2-26.6 N/mm).

CONCLUSION

Surgical repair of simulated unstable meso-type os acromiale by a combination of cannulated screws with a tension band leads to significantly higher repair strength at time zero in a cadaveric model compared with cannulated screws alone.

Interventions for treating fractures of the patella in adults

BACKGROUND

Fractures of the patella (kneecap) account for around 1% of all human fractures. The treatment of these fractures can be surgical or conservative (such as immobilisation with a cast or brace). There are many different surgical and conservative interventions for treating fractures of the patella in adults.

OBJECTIVES

To assess the effects (benefits and harms) of interventions (surgical and conservative) for treating fractures of the patella in adults.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (2 May 2014), the Cochrane Central Register of Controlled Trials (The Cochrane Library, 2014, Issue 4), MEDLINE (1946 to April Week 4 2014), Ovid MEDLINE In-Process & Other Non-Indexed Citations (2 May 2014), Embase (1980 to 2014 Week 17), LILACS (1982 to 2 May 2014), trial registers and references lists of articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs that evaluated any surgical or conservative intervention for treating adults with fractures of the patella were eligible for inclusion. The primary outcomes were patient-rated knee function and knee pain, and major adverse outcomes.

DATA COLLECTION AND ANALYSIS

At least two review authors independently selected eligible trials, assessed risk of bias and cross-checked data extraction. Where appropriate, results of comparable trials were pooled.

MAIN RESULTS

We included five small trials involving 169 participants with patella fractures. Participant age ranged from 16 to 76 years. There were 68 females and 100 males; the gender of one participant was not reported. Two trials were conducted in China and one each in Finland, Mexico and Turkey.All five trials compared different surgical interventions. Two trials compared biodegradable versus metallic implants for treating displaced patella fractures; one trial compared patellectomy with advancement of vastus medialis obliquus versus simple patellectomy for treating comminuted patella fractures; and two trials compared percutaneous osteosynthesis (both procedures were 'novel' and one used a new device) versus open surgery for treating displaced patella fractures. All the trials had design flaws, such as lack of assessor blinding, which put them at high risk of bias, potentially limiting the reliability of their findings. No trial reported on health-related quality of life, return to previous activity or cosmetic appearance.Very low quality evidence from two trials (48 participants) comparing biodegradable versus metallic implants indicated little difference between the two interventions at two-year follow-up in the numbers of participants with occasional knee pain (1/23 versus 2/24), incurring adverse events (3/24 versus 1/24) or with reduced knee motion (2/23 versus 2/24). Neither trial reported patient-rated knee function scores. In one trial, as per routine practice, metallic implants were removed one year after surgery (four participants). The other trial did not report on this aspect.Very low quality evidence from one trial (28 participants) indicated that compared with simple patellectomy, patellectomy with advancement of vastus medialis obliquus surgery for treating comminuted patella fractures resulted in more participants with a 'good' result based on a subjectively rated score (12/12 versus 11/16; risk ratio (RR) 1.42, 95% confidence interval (CI) 1.01 to 2.01), fewer participants experiencing knee pain (5/12 versus 13/16; RR 3.11, 95% CI 1.01 to 9.60) and more participants with unlimited activity and no loss in quadriceps strength at four-year follow-up. The only adverse event reported was a patellar tendon subluxation in the simple patellectomy group.Neither trial comparing percutaneous osteosynthesis (using novel devices or methods) versus open surgery reported on patient-rated knee function scores. Very low quality evidence from two trials (93 participants) showed that percutaneous osteosynthesis improved knee pain measured using visual analogue scale (0 to 10 where 10 is worst pain) at one month (mean difference (MD) -2.24, 95% CI -2.80 to -1.68) and at up to three months (MD -1.87, 95% CI -2.45 to -1.29). This effect did not persist at six months (very low quality evidence from one trial). Very low quality evidence from the two trials showed significantly fewer participants with adverse events (loss of reduction, infection, hardware complications, delayed wound healing) after percutaneous surgery (8/47 versus 28/46; RR 0.28, 95% CI 0.14 to 0.55). Very low quality evidence from the two trials indicated better clinician-rated knee function scores after percutaneous fixation at two to three months and 12 months follow-up; however, the between-group difference was not clinically important at 24 months. Very low quality evidence showed a lower incidence of hardware removal in the percutaneous group at two years; however, the results in the two trials were heterogeneous and the reasons for removal were not given in detail.

AUTHORS' CONCLUSIONS

There is very limited evidence from RCTs about the relative effects of different surgical interventions for treating fractures of the patella in adults. There is no evidence from RCTs evaluating the relative effects of surgical versus conservative treatment or different types of conservative interventions.Based on very low quality evidence, biodegradable implants seem to be no better than metallic implants for displaced patellar fractures; patellectomy with vastus medialis obliquus advancement may give better results than simple patellectomy for comminuted patellar fractures; and two novel methods of percutaneous osteosynthesis may give better results than conventional open surgery. However, until conclusive evidence becomes available, treatment options must be chosen on an individual patient basis, carefully considering the relative benefits and harms of each intervention and patient preferences. Further randomised trials are needed, but in order to optimise research effort, these should be preceded by research that aims to identify priority questions.

Plating of patella fractures: techniques and outcomes

Operative treatment of displaced patella fractures with tension band fixation remains the gold standard, but is associated with a significant rate of complications and symptomatic implants. Despite the evolution of tension band fixation to include cannulated screws, surprisingly little other development has been made to improve overall patient outcomes. In this article, we present the techniques and outcomes of patella plating for displaced patella fractures and patella nonunions.

Separate vertical wiring for the fixation of comminuted fractures of the inferior pole of the patella

PURPOSE

Among patients over 50 years of age, separate vertical wiring alone may be insufficient for fixation of fractures of the inferior pole of the patella. Therefore, mechanical and clinical studies were performed in patients over the age of 50 to test the strength of augmentation of separate vertical wiring with cerclage wire (i.e., combined technique).

MATERIALS AND METHODS

Multiple osteotomies were performed to create four-part fractures in the inferior poles of eight pairs of cadaveric patellae. One patella from each pair was fixed with the separate wiring technique, while the other patella was fixed with a combined technique. The ultimate load to failure and stiffness of the fixation were subsequently measured. In a clinical study of 21 patients (average age of 64 years), comminuted fractures of the inferior pole of the patellae were treated using the combined technique. Operative parameters were recorded from which post-operative outcomes were evaluated.

RESULTS

For cadaveric patellae, whose mean age was 69 years, the mean ultimate loads to failure for the separate vertical wiring technique and the combined technique were 216.4±72.4 N and 324.9±50.6 N, respectively (p=0.012). The mean stiffness for the separate vertical wiring technique and the combined technique was 241.1±68.5 N/mm and 340.8±45.3 N/mm, respectively (p=0.012). In the clinical study, the mean clinical score at final follow-up was 28.1 points.

CONCLUSION

Augmentation of separate vertical wiring with cerclage wire provides enough strength for protected early exercise of the knee joint and uneventful healing.

Adjustable patella grapple versus cannulated screw and cable technique for treatment of transverse patellar fractures

BACKGROUND

Although the cannulated screw and cable (CSC) tension band technique is an effective method for fixation of transverse patellar fractures, it has shortcomings, such as extensive soft tissue damage, osseous substance damage, and complex manipulation. We conducted a retrospective comparison of the adjustable patella grapple (APG) technique and the CSC tension band technique.

PATIENTS AND METHODS

We retrospectively reviewed 78 patients with transverse patellar fractures (45 in the APG group and 33 in the CSC group). Follow-up was 18 months. Comparison criteria were operation time, fracture reduction, fracture healing time, the knee injury and osteoarthritis outcome score for knee function, and complications.

RESULTS

The APG group showed shorter operation time and equal fracture reduction, fracture healing time, and knee function compared with the CSC group. Eleven patients in the APG group experienced skin irritation generated by implants. There was no complication in the CSC group.

CONCLUSIONS

The APG technique should be considered as an alternative method for treatment of transverse patellar fractures.

Percutaneous cerclage wiring for the surgical treatment of displaced patella fractures

The patella plays an important role in the knee joint extension, and a patella fracture requires surgical treatment when it is accompanied by displacement of bone fragments and a joint surface gap. In patella fractures, there is disruption of the soft tissue structures that support the knee extension mechanism. We use a method of percutaneous cerclage wiring to fix the patella and include the peripatellar soft tissues in five patients. All cases were closed fractures, and the AO classification was type A in 1 and type C in 4. At a mean follow-up of 11.2 months, union was achieved in four cases with failure in one inferior pole fracture avulsion. There was no extensor lag noted in any patient, with mean flexion at 141° (120–160). As this percutaneous cerclage wiring method includes soft tissue approximation in the wiring, it may be especially suitable for comminuted fractures for which classic tension band wiring techniques cannot be used. We employed this procedure to atraumatically manipulate peripatellar soft tissues together with the fracture fragments in order to obtain optimal restoration of continuity of the extensor mechanism.