Treating patella fractures with a locking patella plate - first clinical results

Clinical and functional outcomes of locked plating vs. cerclage compression wiring for AO type C patellar fractures- a retrospective single-center cohort study

PURPOSE

Although "tension-band wiring" is still commonly used to stabilize patellar fractures, the technique has recently been scrutinized due to biomechanical insufficiency. Consequently, the AO Foundation renamed the principle to compression cerclage wiring (CCW). Several studies propose favorable outcomes when utilizing locked plating (LP). This study aims to compare outcome of CCW and LP for complex patellar fractures.

METHODS

A retrospective, single-center cohort study was performed on patients who underwent operative treatment for (AO 34 C-Type) patellar fractures between April 2013 and March 2023. Patients with a 12 month follow up were included. We grouped and compared patients based on the applied treatment strategy: group LP vs. group CCW. Primary outcome parameters included implant-related complications and revision surgeries. Secondary outcomes were length of stay, return to work and 12 months functional outcome (Lysholm score). Odd ratios for complications and revisions were calculated using the conditional Maximum Likelihood Estimate. The threshold for statistical significance was set at p < 0.05.

RESULTS

Of 145 patients, 63 could be included (group LP: n = 23 and group CCW: n = 40). Fractures in group LP were significantly more complex in regard to AO Classification (p < 0.001), number of fragments (p < 0.001) and degree of comminution (p < 0.001), yet odds of complications were significantly lower in group LP (OR: 0.147; 95%CI: 0.015-0.742; p = 0.009). K-wire migration was the most common complication in group CCW (20%). Odds of revision surgery were significantly lower in group LP (OR: 0.000; 95%CI: 0.000-1.120; p = 0.041). The average Lysholm score at one year was favorable in both groups (89.8; SD: 11.9 in group LP and 90.6; SD: 9.3 in group CCW; n.s.).

CONCLUSION

In our study cohort, LP was routinely chosen for more complex fracture morphologies; nevertheless the data implies that LP may be considered as the superior fixation technique in regard to complications and revision operations. Especially, K-wire migration occurs frequently after CCW. The one year functional outcome was comparable between the groups, with both demonstrating good results. Prospective randomized studies are indicated to validate our findings.

Novel technique for comminuted patellar fixation using suture tape in spiderweb configuration

Introduction

Patella fractures account for 1% of skeletal fractures in orthopedic surgery. Simple two-part patella fractures are uncommon; most fractures are comminuted with significant articular involvement. Traditionally, patella fractures have been fixed using a tension band technique with cerclage wire, which has several complications including soft-tissue irritation, implant migration, and breakage, leading to secondary implant removal in up to 37% of patients. Newer fixation methods using cannulated screws, hook plates, mesh plates, and locking plates show promise but are costly and require extensive soft-tissue dissection. There is a need for a better alternative, especially for the elderly with osteoporotic bones.

Recent developments

Various authors have described patellar fixation techniques augmented with sutures and suture tape, showing satisfactory outcomes. This paper proposes a novel all-suture tape method for patellar fixation, suitable for common types of patella fractures including AO 34C1.1 (transverse), AO 34C2 (transverse and split), and 34C3 (comminuted). Suture tape is biomechanically superior in both soft tissue and bone.

Operative technique

The patient is laid supine with the knee in full extension. A standard anterior midline approach is adopted. After reducing the fracture fragments and securing them with K-wires, non-absorbable suture tapes are used instead of cerclage wire. The tapes are passed multiple times through the soft tissue, creating loops that are then tensioned to compress the fracture fragments. The technique is completed by creating a tension band fixation with additional suture tapes.

Expected outcomes

This technique offers several benefits, including reduced operative time, minimized soft-tissue dissection, and lower risk of implant prominence and irritation. The suture tape's superior tensile strength and low tissue reactivity reduce complications and the need for secondary surgeries. Early results from two cases show union achieved at 3 months without complications, with patients regaining full range of motion.

Conclusion

This preliminary technical paper demonstrates the feasibility of using non-metallic implants for patella fracture fixation. The proposed method shows promising results, suggesting a potential shift in the approach to fracture fixation. Further research and larger cohort studies are needed to validate these findings.

Anterior variable angle locking neutralisation plate superiority over traditional tension band wiring for treating transverse patella fractures

Purpose

This paper investigates the biomechanical benefits of using hybrid constructs that combine cannulated screws with tension band wiring (TBW) cerclage compared to cannulated screws with anterior Variable Angle locking neutralisation plates (VA LNP). These enhancements can bear heavier loads and maintain the repaired patella's integrity, in contrast to traditional methods.

Method

Eighteen fresh-frozen human cadaver patellae were carefully fractured transversely at their midpoints using a saw. They were then divided into two groups of nine for subsequent utilisation. Fixation methods included Cannulated Screw Fixation added with either TBW or VA LNP Fixation Technique. Cyclic loading simulations (500 cycles) were conducted to mimic knee motion, tracking fracture displacement with Optotrak. After that, the constructs were secured over a servo-hydraulic testing machine to determine the load-to-failure on axial mode.

Results

The average fracture displacement for the anterior neutralisation plate group was 0.09 ± 0.12 mm, compared to 0.77 ± 0.54 mm for the tension band wiring with cannulated screw group after 500 cyclic loading. This result is statistically significant (p = 0.004). The anterior neutralisation plate group exhibited a mean load-to-failure of 1359± 21.53 N, whereas the tension band wiring group showed 780.1 ± 22.62 N, resulting in a significant difference between the groups (p = 0.007).

Conclusion

This research highlights the superior biomechanical advantage of VA LNP over TBW for treating simple transverse patella fractures with two cannulated screws. It also highlights how the TBW is still a valuable option considering the load-to-failure limit.

Level of Evidence

Not Applicable.

Transverse patella fracture fixation: A cadaveric biomechanical comparison of cannulated screws and anterior tension band versus low-profile, multiplanar mesh plating

INTRODUCTION

Multiplanar mesh plating of patella fractures has become more popular in recent years. It was the goal of this study to compare the biomechanical stability of cannulated screw with anterior tension band to multiplanar mesh plating for fixation of transverse patella fractures in cadaver specimens.

MATERIALS AND METHODS

Eight matched pairs of fresh frozen cadaveric knees were obtained and soft tissues dissected leaving the extensor mechanism, joint capsule, and retinaculum intact. Transverse fractures were created at the mid-portion of the patella. For each pair, one specimen was repaired using cannulated screws with anterior tension band, and the second was repaired using multiplanar mesh plating. Each specimen underwent cyclic extension loading with loads increasing by 1.1 kg after every 50 cycles. Interfragmentary displacement was measured at the end of each interval at both 5° and 45° of knee flexion angle, with fixation failure defined by >2 mm displacement.

RESULTS

The specimens fixed with multiplanar mesh plating survived more cycles and higher loads than the specimens fixed with cannulated screws with anterior tension band (p = 0.011 comparing survival plots). After 150 cycles of extension loading, 3 of 8 of the specimens fixed with screws/tension band had failed, whereas none of the mesh plated specimens had failed. After 400 cycles, 7 of 8 of the screws/tension band had failed, whereas half of the mesh plated specimens had failed.

CONCLUSIONS

While a more technically challenging and expensive technique, mesh plating for patella fractures appears to offer greater durability than traditional cannulated screw with tension banding.

Study on the therapeutic effect of Kirschner wire tension band combined with anchor cross-stitch technique in the treatment of comminuted patellar inferopolar fractures

PURPOSES

Fractures of the inferior patellar pole, unlike other patellar fractures, present challenges for traditional surgical fixation methods. This article introduces the clinical technique and outcomes of using Kirschner wire tension band combined with anchor screw cross-stitch fixation for comminuted inferior patellar pole fractures.

METHODS

This retrospective case series study included 14 patients with comminuted inferior patellar pole fractures treated at our institution from September 1, 2020, to April 30, 2022. All patients underwent surgery using the Kirschner wire tension band with anchor screw cross-stitch technique. Follow-up assessments involved postoperative X-rays to evaluate fracture healing, as well as clinical parameters such as healing time, Visual Analog Scale (VAS) scores, range of motion (ROM), and Bostman scores.

RESULTS

All patients were followed for an average of over 12 months, with no cases of internal fixation failure. Knee joint stability and function were excellent. X-rays revealed an average healing time of approximately 10.79 ± 1.53 weeks, hospitalization lasted 5.64 ± 1.15 days, surgery took approximately 37.86 ± 5.32 minutes, and intraoperative blood loss was 33.29 ± 8.15 ml. One patient experienced irritation from the internal fixation material. At the final follow-up, the Bostman score averaged 28.29 ± 0.83, knee joint flexion reached 131.07° ± 4.88°, all patients achieved full knee extension, and the VAS score was 0.36 ± 0.63.

CONCLUSION

Kirschner wire tension band with anchor screw cross-stitch fixation for comminuted inferior patellar pole fractures delivered satisfactory clinical outcomes. This surgical method, characterized by its simplicity and reliability, is a valuable addition to clinical practice.

Lateral rim variable angle locked plating versus tension band wiring of simple and complex patella fractures: a biomechanical study

INTRODUCTION

Treatment of both simple and complex patella fractures is a challenging clinical problem. Although tension band wiring has been the standard of care, it can be associated with high complication rates. The aim of this study was to investigate the biomechanical performance of recently developed lateral rim variable angle locking plates versus tension band wiring used for fixation of simple and complex patella fractures.

MATERIALS AND METHODS

Sixteen pairs of human anatomical knees were used to simulate either two-part transverse simple AO/OTA 34-C1 or five-part complex AO/OTA 34-C3 patella fractures by means of osteotomies, with each fracture model created in eight pairs. The complex fracture pattern was characterized by a medial and a lateral proximal fragment, together with an inferomedial, an inferolateral, and an inferior (central distal) fragment mimicking comminution around the distal patellar pole. The specimens with simple fractures were pairwise assigned for fixation with either tension band wiring through two parallel cannulated screws or a lateral rim variable angle locking plate. The knees with complex fractures were pairwise treated with either tension band wiring through two parallel cannulated screws plus circumferential cerclage wiring or a lateral rim variable angle locking plate. Each specimen was tested over 5000 cycles by pulling on the quadriceps tendon, simulating active knee extension and passive knee flexion within the range of 90° flexion to full extension. Interfragmentary movements were captured via motion tracking.

RESULTS

For both fracture types, the articular displacements measured between the proximal and distal fragments at the central patella aspect between 1000 and 5000 cycles, together with the relative rotations of these fragments around the mediolateral axis were all significantly smaller following the lateral rim variable angle locked plating compared with tension band wiring, p ≤ 0.01.

CONCLUSIONS

From a biomechanical perspective, lateral rim variable angle locked plating of both simple and complex patella fractures provides superior construct stability versus tension band wiring under dynamic loading.

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.

To plate, or not to plate? A systematic review of functional outcomes and complications of plate fixation in patellar fractures

PURPOSE

Poor outcomes and high complication and reoperation rates have been reported with tension-band wiring (TBW) in the management of patellar fractures and particularly the comminuted ones. The purpose of this study was to investigate the functional outcomes and complication rates of patellar fractures managed with open reduction and internal fixation (ORIF) with a plate.

METHODS

MEDLINE, EMCare, CINAHL, AMED and HMIC were searched, and the PRISMA guidelines were followed. Two independent reviewers extracted the data from the included studies and assessed them for the risk of bias.

RESULTS

Plating of patellar fractures is associated with satisfactory range of movement (ROM) and postoperative function and low pain levels. We found a 10.44% complication rate and a low reoperation rate. Reoperations were mainly performed for metalwork removal.

CONCLUSION

ORIF with plating of patellar fractures is a safe alternative in the management of patellar fractures and may be associated with a lower complication and reoperation rate compared to TBW. Future randomized prospective studies are needed to validated the results of the present systematic review.

High return to sports rates after operative treatment of patella fractures

BACKGROUND

Patella fractures are relatively rare fractures and only little is known about the postoperative return to sports after patella fractures.

METHODS

This retrospective study presents information on functional outcome after operative treatment of patella fractures as well as time until return to sports and patients' complaints after open-reduction internal-fixation (ORIF) of patella fractures.

RESULTS

Overall, 39 patients after ORIF of patella fractures were evaluated at our Level-I trauma center with a mean follow-up of 42 months. The mean time until return to sports was 7 ± 3.9 months. No significant difference was found for functional outcome with respect to body mass index (BMI) or age. Fracture consolidation was accomplished after a mean of 6.9 ± 2.9 months besides a relatively low complication rate of 5.1% (n = 2).

CONCLUSION

The results demonstrate a high return to sports rate of 90.3%. However, only 51.6% were able to perform sports on their pre-injury level or above. Trial Registration The study was retrospectively registered at DRKS (No: DRKS00031146).

[Anterior plate osteosynthesis for multifragmentary patella fracture with additive stabilization of the distal pole using suture cerclage]

OPERATION GOAL

The aims of the surgical treatment are the anatomical reduction of the articular surface and stabilization of a multifragmentary patella fracture with a distal pole fragment using plate osteosynthesis and additive suture tape cerclage to secure the distal fragment.

INDICATION

Demonstration of the surgical procedure for a multifragmentary patella fracture in the knee joint of a male cadaver.

SURGICAL TECHNIQUE

Start with a median prepatellar skin incision and splitting of the bursa and surrounding fascia. Lateral arthrotomy with proximal and distal extension for complete eversion and articular exposure of the multifragmentary fracture. The fracture is then reduced from the articular side using temporary K‑wire fixation and reduction clamps, followed by screw osteosynthesis of the large fragments (e.g., distal and proximal poles). After selection of the plate it is fixed with locking screws. In addition, a suture cerclage according to Krakow and/or McLaughlin is applied distally and transosseously through the tibial tuberosity and proximally through the quadriceps tendon. The knotting of the McLaughlin suture cerclage should be done in 90° flexion of the knee joint.

POSTOPERATIVE TREATMENT

Functional postoperative treatment with hard shell orthesis with movement limitation (30°, 60° and 90° for 2 weeks each) and partial weight bearing of 15-20 kg for 6 weeks is recommended. Full weight-bearing is only allowed in full extension.

EVIDENCE

Plate osteosynthesis is biomechanically superior in comparison to the widely used tension band osteosynthesis. In multifragmentary fractures, additional augmentation with a suture tape cerclage seems to be appropriate. Due to the lack of study results there is currently no clinical evidence for this.

Anterior variable-angle locked plating versus tension band wiring of simple and complex patella fractures - a biomechanical investigation

BACKGROUND

The aim of this study was to investigate the biomechanical performance of novel anterior variable-angle locking plates versus tension band wiring used for fixation of simple and complex patella fractures.

METHODS

Sixteen pairs of human cadaveric knees were used to simulate two-part simple transverse AO/OTA 34-C1 and five-part complex AO/OTA 34-C3 patella fractures. The complex fracture pattern was characterized with a medial and a lateral proximal fragment, together with an inferomedial, an inferolateral and an inferior fragment mimicking comminution around the distal patella pole. Eight pairs with simple fractures were split for fixation via either tension band wiring (TBW) through two parallel cannulated screws or anterior variable-angle locked plating, whereas other eight pairs with complex fractures were split for either TBW through two parallel cannulated screws plus circumferential cerclage wiring, or anterior variable-angle locked plating using a cortical caudo-cranial polar screw. Each specimen was tested over 5000 cycles with a range of motion from 90° flexion to full extension by pulling on the quadriceps tendon. Interfragmentary movements were captured by motion tracking.

RESULTS

For both fracture types, the longitudinal and shear articular displacements, measured between the proximal and distal fragments at the central patella aspect between 1000 and 5000 cycles, together with the relative rotations of these fragments around the mediolateral axis were all significantly smaller following anterior variable-angle locked plating versus TBW, p ≤ 0.01.

CONCLUSIONS

From a biomechanical perspective, anterior locked plating of both simple and complex patella fractures resulted in less interfragmentary displacement under extended cyclic loading.

Developments in the epidemiology and surgical management of patella fractures in Germany

BACKGROUND

Patella fractures account for approximately 1% of all skeletal injuries. Treatment options are vast and no definitive conclusion on what option is the most beneficial could be made so far. Plate osteosynthesis appears to gain in importance. We aim to give insight into the more recent trends and developments as well as establish the epidemiology of patella fractures in Germany by analysing treatment and epidemiological data from a national database.

METHODS

Anonymised data was retrieved form a national database. In the period of 2006 to 2020, all patients with patella fractures as defined in ICD-10 GM as their main diagnosis, who were treated in a German hospital were included. Patients were divided into subgroups based on gender and age. Age groups were created in 10-year intervals from 20 years old up to 80 years old with one group each encompassing all those above the age of 80 years old and below 20 years old and younger. Linear regression was performed were possible to determine statistical significance of possible trends.

RESULTS

A total of 151,435 patellar fractures were reported. 95,221 surgical interventions were performed. Women were about 1.5 times more likely to suffer from patella fracture than men. The relative number of surgical interventions rose from about 50% in 2006 to 75% in 2020. Most surgical interventions are performed in those over the age of 50. The incidence of complex fractures and plate osteosynthesis has significantly increased throughout the analysed period.

CONCLUSIONS

We found a clear trend for surgical treatment in Germany with an increase in surgical procedures. We could also show that this ratio is age-related, making it more likely for younger patients in the age groups from 0 to 70 years old to receive surgical treatment for their patella fracture.

Adjunct neutralization plating in patella fracture fixation: a technical trick

Patella fracture outcomes are positive overall; however, in some cases, traditional fixation methods result in complications, including loss of fixation and irritable hardware requiring removal. We present a technique of plate fixation that we believe has the potential to improve stability and is less offensive in more comminuted fracture patterns. Improved stability should allow unfettered advancement of rehabilitation without concern for loss of fixation. Lower profile fixation offers a potential for diminishing the presence of irritating hardware requiring removal. We present our technique for using plate fixation to augment more complex patella fracture patterns.

Treating Inferior Pole Fracture of Patella with Hand Plating System: First Clinical Results

OBJECTIVE

Inferior pole fractures of patella are notorious fractures where it is difficult to obtain rigid internal fixation by conventional methods. The objective of the study was to introduce the Hand Plating System (HPS), which was a novel surgical technique for inferior pole fractures of patella, and to report the radiological and clinical outcomes following the application of the surgical technique.

METHODS

The study was designed as a retrospective cohort study. Between July 2017 and December 2018, 30 patients who were diagnosed with inferior pole fracture of the patella without additional orthopaedic injuries were enrolled in this case series. After X-ray and 3D-CT examinations, all patients underwent open reduction and internal fixation by HPS with or without supplementary cannulated screw and lag screw stabilization. The bony union time, final range of motion (ROM), Bostman score, visual analog scale (VAS), and complications were measured as the clinical outcomes under a minimum of 12 months of follow-up.

RESULTS

All of the operations went well with the mean operative time of 76.2 ± 15.3 min. Bony union achieved in all the cases at an average of 9.5 ± 1.4 weeks after surgery. There was no loss of reduction, fixative failure, or surgical implant removal during follow-up. The average range of motion 1 year postoperatively was 0°-123.3°. The mean Bostman Score at the last follow-up was 26.8 ± 2.1 with the satisfactory rate of 100%. The pain feeling during walking as measured by VAS averaged at 0.9 ± 1.3. No complications developed except for one case of poor incision healing, which healed eventually after surgical debridement.

CONCLUSIONS

HPS was demonstrated as a secure fixation and as a kind of tension band for inferior pole fractures of the patella. Satisfactory recovery of knee function and low complication rate, including no need for hardware removal, could be expected.

Anterior Locking Plate Osteosynthesis of Patellar Factures - Analysis of Complications and Functional Outcome

BACKGROUND

Tension band wiring is the standard procedure for patellar fractures, but is associated with a high rate of implant related complications and implant failure. Tension band wiring may fail, especially with multifragmentary and comminuted fractures. Plate fixation of complex patellar fractures seems to be superior to wiring, both clinically and biomechanically. The aim of this study was to evaluate complications after locking plate fixation in patellar fractures two years after surgery and to access the functional outcome.

MATERIAL AND METHODS

As part of a prospective case series, all patients who had received locking plate fixation of a patellar fracture between April 2013 and May 2018 were clinically examined two years postoperatively and potential complications were evaluated.

RESULTS

A total of 38 patients aged 19 - 87 years were included. Complications occurred in a total of five patients (13%), including one reactive prepatellar bursitis, one chronic infection and loss of reduction due to a dislocated pole fragment in three cases. The average active range of motion of the affected knee joint two years postoperatively was 133°. The Tegner activity scale score reached 3 points, the Lysholm score 95 points and the Kujala score 95 points.

CONCLUSION

With an overall relatively low complication rate and good clinical outcome, dislocated distal pole fragments are a common complication after plate fixation of patellar fractures. If preoperative diagnostic testing shows a pole fragment, a modified hook-plate can be used, with the possibility of fixing the pole fragment.

Reoperation and Complication Rates Following Patellar Fracture Repair with Plates: A Retrospective Analysis with Patient-Reported Outcomes at More than 1 Year of Follow-up

Recent work has suggested good clinical and functional results with dorsal surface plating of patellar fractures. The primary outcome measurement of this study was reoperation rates for patellar fractures that had been treated with dorsal plating.

Methods

This work consists of a retrospective review of clinical and functional outcome data following repair of patellar fractures with dorsal plates. We obtained institutional review board approval for this study and conducted a review of 9 consecutive years of our group's trauma practice. We also contacted patients to assess patient-reported outcomes (PROs) after 12 months.

Results

Eighty-five patellar fractures were treated with open reduction and internal fixation (ORIF) via plating over 9 years. Eight (9.41%) of the patients required reoperation. Of the 72 patients with complete follow-up of ≥12 weeks, 3 (4.17%) had nonunion of the fracture site and 4 (5.56%) had loss of reduction of the fracture. The average Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score among our sample was 18.84 (slight symptoms); 72.41% of the patients in our sample had slight or no symptoms at ≥12 months postoperatively.

Conclusions

Our results indicated that plating of comminuted patellar fractures is a safe, viable treatment strategy. The PROs at ≥12 months of follow-up data were promising. Additionally, dorsal plating may allow for early return of function and less postoperative bracing.

Level of Evidence

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

Influence of patella height after patella fracture on clinical outcome: a 13-year period

INTRODUCTION

The incidence of patella fracture is statistically low (0.5-1.5%) compared to other fractures of the extremities [Patella fractures 76(10):987-997, 2005]. In the latter research, patella fractures if treated surgically present an overall inferior functional outcome. Little is known about the influence of the postoperative patella height on the clinical outcome. Therefore, the aim of our study was to analyse the influence of the patella height on the patients' functional outcome after surgery.

METHODS

In this retrospective study the in-house trauma register of our level I University trauma center was screened for patients suffering patella fractures treated surgically. Patella height of the same patients was evaluated on lateral X-rays using the Insall-Salvati Ratio (ISR). The patients' X-rays were analyzed at two time points for the ISR, whereas group A presents ISR data right after surgery and group B data at the latest follow up (minimum 6 weeks). The change of mean ISR at both time points was tested for significance. The functional outcome was measured by the "Munich Knee Questionaire" (MKQ). These MKQ results of different patella heights and fracture types were compared.

RESULTS

The screening of our in-house trauma register revealed 375 patients between the years 2003 and 2016. Out of these 54 patients (34f, 20 m) were enrolled. In detail the follow-up time for ISR between group A and B accounted for a mean of 503.8 ± 655.7 days. The MKQ was assessed at a mean of 1367.0 ± 1042.8 days after surgery. According to the AO-classification 10% AO.34 type B and 90% AO.34 type C fractures were found. Group A showed in 9.1% a patella baja and in 27.3% a patella alta compared to group B presenting 20.0% patella baja and 14.5% patella alta. There was no significant difference in functional outcome referring to the MKQ in patella alta (MKQ 69.0% ± 18.2) or baja (MKQ 67.1% ± 17.9) (p = 0.9). No significant functional difference between AO34.type B (MKQ 74.5% ± 11.0) and AO34.type C fractures (MKQ 64.0% ± 15.0) resulted (p = 0.1).

CONCLUSION

Our results demonstrate that different postoperative patella heights apparently do not influence the functional outcome in the short follow-up.

"Fishing net" suture augmenting tension-band wiring fixation in the treatment of inferior pole fracture of the patella

INTRODUCTION

Inferior pole fracture of the patella (IPFP) is difficult to repair and stabilize clinically. Although various fixation techniques have been developed, fixation strength and mobility remain daunting challenges to orthopedic surgeons. The goal of this research is to evaluate the biomechanical strength and clinical outcomes of a novel "fishing net" suture fixation procedure.

MATERIALS AND METHODS

Four finite element models, modified tension-band wiring fixation, anchor suture fixation, basket plate fixation and "fishing net" suture fixation were built to compare the fixing efficacy of "fishing net" suture fixation with three other fixation methods during IPFP fixation. From January 2018 to February 2019, 17 patients who suffered IPFP and treated by "fishing net" suture (FNS) fixation were compared with 20 patients treated by tension-band wiring (TBW) fixation in database and the two groups were evaluated postoperatively using the modified Cincinnati knee rating system.

RESULTS

Biomechanical evaluation showed that the relative displacement values of proximal patella measured by three pairs of points on both sides of the fracture line were the lowest using the "fishing net" suture fixation, while fixation using tension-band wiring and basket plate showed similar levels of stability that were less desirable than the "fishing net" method. As to clinical outcomes, there were 17 (100%) patients exhibited excellent or good results with no internal fixation failures in the FNS group compared to three internal fixation failures in the TBW group.

CONCLUSION

The biomechanical and clinical results suggest that the "fishing net" suture fixation is a viable candidate for fixation of IPFP.

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.

Patellar Fractures: Anatomy, Mechanics, and Surgical Management

➤

A preoperative computed tomography scan may be considered to improve surgical planning, as secondary fracture lines are poorly visualized on radiographs.

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Oblique internal and external rotation fluoroscopic views may be used intraoperatively to fully evaluate the medial and lateral facet articular reduction if direct assessment by visualization or palpation is not completed.

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Partial patellectomy for inferior pole fractures should be avoided, and bone-preserving procedures are recommended.

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A lateral arthrotomy may be used for direct visualization of the articular reduction for multifragmentary fractures. An inferomedial arthrotomy should be avoided to protect the dominant blood supply of the patella.

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Tension band fixation with cannulated screws yields a lower reoperation rate, improved functional outcome scores, and better performance in biomechanical studies than Kirschner wire-based tension band fixation.

➤

Preliminary studies of novel plate and screw constructs for osteosynthesis have shown promising results.

Loop Anchor Tension Band Technique for Patella Fractures Lowers the Rate of Kirschner Migration

OBJECTIVE

To compare the complications of patella fracture after open reduction and internal fixation using our innovative, loop-based modification of the tension band wiring technique and the traditional tension band wiring technique.

METHODS

Fifty-eight patients with patella fracture (AO/OTA: 34-C) were enrolled in this retrospective case-control study during the study period. We treated 36 patients with the traditional tension band wiring and 22 patients with our loop anchor tension band technique. Lysholm knee scoring scale, sex, numbers of wire dislodge, number of implants removal between two groups were compared.

RESULTS

The number of cases of wire dislodgement was zero in the loop anchor tension band group and seven in the traditional tension band group. There was statistically significant difference (P = 0.037). Lysholm knee score (P = 0.685) and operation time (P = 0.395) were not significantly different between the two groups CONCLUSIONS: The loop anchor tension band technique is safe and effective for treating patella fractures. The rates of implant loosening and wire pull-out were significantly lower in the loop anchor tension band group than those in the traditional technique group.

Oesophageal carcinoma with solitary patellar metastasis: a rare case report

The incidence of tumours found in the patella, including primary and metastatic tumours, is low. Solitary metastasis of oesophageal carcinoma (OC) in the patella is even rarer. A 50-year-old man presented to our clinic because of pain and limited range of motion in the right knee for 4 hours and after a fall. On the basis of the patient’s medical history, he was diagnosed with OC 2 months previously and underwent two cycles of paclitaxel liposome combined with tiggio chemotherapy (oral tiggio, 40 mg, two times/day, with a treatment cycle of 3 weeks). A 99mTc-methylene diphosphonate bone scintigraphy scan showed increased radioactivity in the right patella. A right knee biopsy showed the presence of patellar metastasis from OC. Unfortunately, the patient denied additional treatment and was discharged for personal reasons. At the 1-month follow-up, which was conducted by a telephone survey, we learned that the patient had died of acute pulmonary embolism. X-rays and computed tomography are useful for diagnosing patellar metastases, but 99mTc-methylene diphosphonate bone scintigraphy can help physicians diagnose patellar metastasis of OC more rapidly. Biopsy with pathology is the gold standard for diagnosing patellar metastases. Additionally, timely surgical treatment prolongs the survival time of these patients.

Patellar Fracture After ACL Reconstruction: Open Reduction and Internal Fixation with a Maxillofacial Plate: A Case Report

CASE

Patellar fractures after anterior cruciate ligament (ACL) reconstruction with a bone-patellar-tendon-bone (BPTB) autograft are a rare complication with a reported incidence of 0.2% to 2.3%. Treatment has previously been nonoperative splinting, lag screws, or a tension-band construct. We present the case of a 14-year-old adolescent girl who suffered a comminuted patella fracture 4 weeks after an ACL reconstruction using a BPTB autograft who subsequently underwent successful operative fixation through a novel technique with the use of a maxillofacial plate and screw system.

CONCLUSION

A maxillofacial plate and screw system is an effective and reliable treatment option for patellar fractures sustained after ACL reconstruction with a BPTB autograft.

Patella Fractures: Approach to Treatment

Patellar fracture morphology varies based on the mechanism of injury. Most fractures are either a result of direct impact or through an indirect eccentric extensor contraction injury. Each fracture pattern requires appropriate preoperative planning and individualization of the fixation method. Displaced fractures affect the extension apparatus, and often require surgical fixation. Surgical treatment is recommended in fractures with any of the following features: articular step-off > 2 mm, > 3 mm of fracture displacement, open fractures, and displaced fractures affecting the extensor mechanism. Meticulous handling of the soft-tissue envelope is of the utmost importance, given the patella's tenuous blood supply and limited soft-tissue envelope. Incongruent articular surface can result in detrimental long-term effects; therefore, surgical treatment is directed toward anatomic reduction and fixation. The evolution of patellar fracture fixation continues to maximize options to balance rigid fixation with low-profile fixation constructs. Improving functional outcomes, minimizing soft-tissue irritation, and limiting postoperative complications are possible by using the therapeutic principles of rigid anatomical fixation and meticulous soft-tissue handling.

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.

Managing Complications of Patellar Fracture Hardware Removal

A simple surgical procedure is not without the risk of complications and when removing hardware from the bone, such as a previous patella fracture hardware, the surgeon must be well aware of this potential. Here we present the case of a 71-year-old male who presented for removal of retained hardware of united right patella fracture with overlying skin complications. Surgical intervention was uneventful. On post-operative day 1, the patient suffered a fall while using the restroom unassisted with a subsequent large amount of bleeding from the incision site. X-rays demonstrated a new displaced inferior pole patellar fracture. The patient returned to the operating room for debridement and repair of this new patellar fracture with primary closure. Intraoperative cultures of initial operative site were positive for Corynebacterium and Staphylococcus epidermidis. The patient was then started on intravenous Vancomycin based on culture sensitivities. The patella fixation/repair was protected with a knee immobilizer as there was increased risk of falls due to his age/underlying medical condition. This case discusses recommendations and guidelines for preventing and managing these various postoperative complications.

Clinical outcomes of Ti-Ni shape-memory patella concentrator combined with cannulated compression screws in the treatment of C2 and C3 patella fracture: a retrospective study of 54 cases

Background

Ti-Ni shape-memory patella concentrator (TNSMPC) has been designed as an alternative approach for fixation of patella fracture, which has some advantages like higher hardness, higher tenacity, better wearing resistance, excellent corrosion resistance and desired histocompatibility. The present study was to investigate the efficiency of TNSMPC combined with cannulated compression screws in the treatment of comminuted patella fractures.

Methods

Between January 2014 and December 2017, 54 patients of C2 and C3 patella fractures underwent open reduction and internal fixation with TNSMPC combined with cannulated compression screws. All the patients got standard postoperative rehabilitation programs and were regularly followed up for at least 12 months after the operation. X-rays, knee functions and life quality were evaluated during the follow-up.

Results

All the patients achieved bone healing and recovery of knee function with low incidence of complications according to outcomes of X-rays and questionnaires. The average operation time and blood loss during surgery were 77.5 ± 25.12 min and 24.25 ± 4.70 ml respectively. The Knee Outcome Survey Activities of Daily Living Scale, the range of motion and the 36-item short-form heath survey after the operation were all improved. According to the Bostman’s criteria, the excellent to good rate was 92.6%.

Conclusion

TNSMPC combined with cannulated compression screws is an effective internal fixation method for C2 and C3 patella fracture with excellent clinical outcomes. In addition, the operation does not increase extra technique difficulty or tissue damage relatively, which is worth promotion.

A comparison of EFECE systems with tension band wiring for patella fracture fixation in cadavers

Background

EFECE systems are newly defined internal fixation systems, which are suitable for patella fracture fixation. The aim of this study was to compare the fixation strength of EFECE Systems with tension band wiring for transverse patellar fracture simulation on fresh frozen cadaver models.

Methods

Quadriceps tendon-patella-patellar tendon (QT-P-PT) complex was prepared from human cadavers. After simulation of a transverse patella fracture, in group 1, 5 patella were fixed with a pair of 1.2 mm EFECE wires and 4 EFECE devices. In group 2, 5 patella were fixed with a pair of 1.2 mm Kirschner wires (K-wire) and a cerclage wire according to the tension band technique.

Using a testing device with custom-made jaws, increasing distraction force was applied to these QT-P-PT complexes. Extension of these complexes with the distraction forces was observed. The maximum distraction force and the elongation during maximum force were evaluated.

Results

After 5 experiments with the EFECE systems, there was no EFECE wire breakage or EFECE wire-EFECE device catching failure. The median maximum force was 740 N (720-810 N). During maximum distraction force the median extension was 2.5 mm (1.6-2.5 mm). After 5 experiments with the tension band technique, there was no K-wire breakage. The median maximum force was 330 N (240-510 N). During this maximum distraction force the median extension was 3.4 mm (2.2-3.8 mm).

Conclusions

Based on the biomechanical advantages, patella fracture treatment with EFECE systems may constitute a reasonable alternative in the treatment of patella fractures.

Percutaneous cerclage wiring for type 34-C patella fracture in geriatric patients

PURPOSE

This study was to retrospectively evaluate clinical outcomes of geriatric patients with patella fracture treated by percutaneous cerclage wiring and to introduce the surgical technique.

METHODS

From January 2009 to December 2015, fifty-seven consecutive geriatric patients of type 34-C patellar fracture underwent closed reduction and percutaneous cerclage wiring fixation in our hospital. Visual Analog Scale (VAS) score, Levack score system, WOMAC test form of pain, stiffness and function, and knee joint range of motion (ROM) were applied for functional evaluation.

RESULTS

Fifty-three patients were followed up for a mean period of 36 months (12 to 82 months). All fractures were unioned, no wound infection, second displacement of fracture fragment or wire migration was found. Wire breakage happened in one case at six months post-operation. Thirteen patients had hardware removed, nine cases for implant irritation at the knot and four cases for no specific reason. No patient developed postoperative knee stiffness, and range of motion was 128.6° (110-140). The average VAS score of emotional knee function was 87.5 (65-99) preinjury and 78.1 (53-95) at the last follow-up. 86.8% (46/53) patients considered that they regained more than 80% of their knee function. The average Levack score was 10.0 (6-12), which included thirty-five evaluations of "excellent" and eighteen of "good". The average WOMAC score was 21.3 (13-37).

CONCLUSIONS

Percutaneous cerclage wiring fixation is a viable option for type 34-C patella fracture in geriatric patients.

Fracture Patterns and Comminution Zones in OTA/AO 34C Type Patellar Fractures

OBJECTIVES

To characterize the fracture patterns and comminution zones for complete articular (OTA/AO 34C type) patellar fractures, using a computed tomography mapping technique.

METHODS

Eighty-three OTA/AO 34C type patellar fractures were included. Images of patellar fractures were superimposed on a coronal template of the patella, created from a healthy right knee, to identify fracture patterns and comminution zones.

RESULTS

Our analysis was based on 83 computed tomography images of patellar fractures, contributed by 69 male and 14 female patients (mean age, 52 years; range, 18-79 years), and included 13 type C1, 26 type C2 and 44 type C3 fractures. A transverse fracture, including both the medial and lateral facets, was the most common fracture pattern, identified in 92.8% of cases. In the C1 and C2 types, the fracture line affecting the medial and lateral joint surface was either transverse or oblique. In the C3 type, the transverse and vertical fracture line of the medial articular surface extended to the inferior pole of the patella, with transverse and oblique fractures lines on the lateral joint surface. In addition, a concentration of the fracture lines around the vertical ridge was observed.

CONCLUSIONS

The patterns of fracture lines and comminution zones OTA/AO 34C type fractures were repeatable on the constructed maps. A transverse fracture line on the inferior pole which was observed in the C2 and C3 type fractures may be used for the modification of current classification systems to direct treatment.

Patella fractures treated with cannulated lag screws and fiberwire® have a high union rate and low rate of implant removal

OBJECTIVES

The purpose of this study is to report the results of open reduction internal fixation of patella fractures (OTA 34 A-C) using cannulated lag screws and FiberWire® (Arthrex, Naples, FL, USA) with regard to union and symptomatic implant removal.

DESIGN

Retrospective review of prospectively collected database.

SETTING

Urban Level 1 trauma center and Level 2 trauma center METHODS: All displaced intra-articular patella fractures (OTA 34 A-C) treated with ORIF by cannulated lag screws and FiberWire® tension band/cerclage between January 1, 2009 and August 1, 2018. Three hundred and eighty seven consecutive patients were identified. Fifty fractures were included in the final analysis.

MAIN OUTCOME MEASUREMENT

All patients were followed to clinical and radiographic union. Nonunion was defined as lack of clinical and radiographic union, fracture displacement, and/or return to OR for revision surgery. Rate of symptomatic implant removal was recorded.

RESULTS

Average age was 57.7 years (range 21-86). Average follow up was 20.6 months (range 6-98 months). Average time to clinical and radiographic union was 3.1 months (range 3-7 months). Four fractures were open. There was a 96% (48/50) rate of primary union, with one patients requiring revision surgery to achieve union, and one developing an asymptomatic radiographic nonunion. The rate of symptomatic implant removal was 8% (4/50). Only 1 of the 4 was operated for a prominent suture knot, and the remaining 3 were for prominent screw removal. Knee range of motion averaged 0.37° extension to 119° flexion (range, 0-150°).

CONCLUSION

Patella fractures can be treated with cannulated lag screws and FiberWire® with a high rate of primary union (96%) and a low rate of symptomatic implant removal (8%). The implant removal rate compares favorably with alternative constructs, with an equivalent rate of fracture union.

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.

Outcomes after locked plating of displaced patella fractures: a prospective case series

PURPOSE

Tension band wiring remains a common treatment for patella fractures, but complication rates are high, with unsatisfactory results. The purpose of this observation study was to evaluate clinical results and complication rates of a novel patella locking plate fixation.

METHODS

Twenty patients (mean age, 59.2 ± 18 years) with displaced patella fractures were prospectively enrolled. Range of motion, knee scores (Tegner, Lysholm, Kujala), complications, and revision surgeries were assessed six weeks, six months, 12 months, and 24 months after surgery. Results were compared to the situation before trauma in regards to the time of follow-up using a paired sample t test.

RESULTS

According to the OTA classification, the fractures were classified as follows: one A1, four C1, six C2, and nine C3. Range of motion improved from 121° after six weeks to 140°, 141°, and 143° within the follow-up period. While the Tegner, Lysholm, and Kujala scores were 4.1/97/97, respectively, before trauma, they improved from 2.6/80/89 to 3.6/94/89, 3.7/95/94, and 4.1/97/97 within the follow-up period. Three patients had a complication (15%): one fracture dislocation, one reactive bursitis, and one renewed fracture. Four patients reported discomfort or anterior knee pain especially when kneeling on the implant.

CONCLUSIONS

The patella locking plate is a safe and effective treatment for patella fractures, including comminuted fractures. Function can be restored within six months after surgery, and the complication rate is low. Nonetheless, the implant can cause discomfort or anterior knee pain especially when kneeling, which can necessitate an implant removal.