Patella Cartilage Status Does Not Affect the Clinical Outcomes of Non-resurfaced Patella in Mobile-Bearing Total Knee Arthroplasty.

Background: During total knee arthroplasty (TKA), patellar retention is performed when the cartilage is fairly well preserved and the thickness of the patella is relatively thin. However, clinical outcomes of the non-resurfaced patella in TKA according to the cartilage status are lacking in the literature. The purpose of this study was to compare patient-reported outcome measures (PROMs) according to the grade and location of the patellar cartilage lesion in TKA patients. Methods: The outcomes of 165 osteoarthritis patients (186 knees) who underwent cemented mobile-bearing TKA without patellar resurfacing were assessed and classified according to the grade and location of the patellar cartilage lesion. PROMs using the Western Ontario and MacMaster Universities Osteoarthritis index, the Knee Society Score (Knee Society Function Score and Knee Society Knee Score), and the Hospital for Special Surgery score were evaluated preoperatively and at postoperative 2, 4, 6, and 8 years. The correlations between PROMs and the grade and location of the cartilage lesion were assessed. Additionally, radiologic outcomes including the patellar tilt angle and patellar height were assessed and their correlation with the grade of cartilage lesion was analyzed. Analysis of variance was used to determine statistical significance. Results: There was no significant difference between PROMs according to the grades and locations of cartilage lesions at any postoperative follow-up. Radiologic parameters also showed no significant differences according to the grades of patellar cartilage lesions. Conclusions: The grade and location of the patellar cartilage lesion had no influence on clinical outcomes in mobile-bearing TKA with patellar retention at short- and long-term follow-up.

Prospective assessment of functional and clinical results of surgical patellar stabilization in rural and urban populations. Equal chance to success?

INTRODUCTION AND OBJECTIVE: Patella dislocation represents 3.3% of all knee injuries often leading to persistent instability. Medial patello-femoral ligament(MPFL) reconstruction is the standard method of treatment in the patellar instability. Rehabilitation after MPFL-R is a long and demanding procedure. The hypothesis presented reflects the idea that despite relatively good access to hospital care and surgical options, the post-operative rehabilitation care system is still inferior in rural areas versus the one offered in major cities and towns. MATERIAL AND METHODS: Between January 2015 - January 2018, 47 patients met the study inclusion criteria, diagnosed and operated on due to patellar instability. 8 patients were lost for full follow-up. Finally, 39 patients were included, divided into two groups - group A (19 from cities), group B (20 from rural area). Prospective KOOS and Kujala scales assessments were conducted: preoperative, 6 and 12 months after surgery. Knee isokinetic muscle strength was measured at 3 stages; prior to surgery, 6 and 12 months after reconstruction. RESULTS: All patients showed significant improvement measured in the KOOS and Kujala scales after the procedure, compared to the pre-operational results. Despite equal clinical improvement, patients from Group A(city) achieved better functional outcomes as presented in the results of knee extensor functional tests using a Biodex dynamometer. CONCLUSIONS: Rehabilitation after MPFL reconstruction improves muscle strength and clinical outcome. Patients from rural areas had inferior functional results in comparison to the patients from major cities, even 12 months after surgical patella stabilization. Despite the development of roads and transport according to the EU cohesion policy, there are still differences in rehabilitation results between rural and city areas.

Incidence of patella baja and pseudopatella baja in aseptic revision total knee arthroplasty.

INTRODUCTION: There are two variants regarding the low location of the patella in relation to the tibio-femoral joint line: patella baja (PB) and pseudo-patella baja (PPB). The purpose of this study is to investigate the incidence of PB and PPB in a cohort of patients that underwent revision total knee arthroplasty (rTKA) for aseptic reasons and describe any differences in each group's ROM. METHODS: This retrospective study included 114 patients that underwent aseptic revision TKA surgery between 2017 and 2022. Patients were revised either for stiffness (Group 1) or aseptic loosening/instability (Group 2). The Insall-Salvati ratio (ISR) and Blackburne-Peel ratio (BPR) were used to evaluate the patellar position. ISR < 0.8 defined PB, while cases with ISR ≥ 0.8 and BPI < 0.54 were defined as PPB. ROM was measured and a subanalysis was conducted to investigate the progression of the values of ISR and BPR. RESULTS: 55 patients comprised Group 1, and 59 patients comprised Group 2. Overall, 13 cases (11.4%) had PB before rTKA and 24 (21%) had PB after rTKA. Cases with PPB were 13 (11.4%) before and 34 (29.9%) after rTKA. Group 1 patients presented with more PB before and after rTKA (12.8% vs 10.2% and 27.3% vs 15.2% respectively). However, after rTKA Group 1 patients presented with less PPB (20%) compared to Group 2 (39%) (p = 0.02). In Group 1, patients with PPB after rTKA had less ROM compared to those without PPB [83.2 (± 21.9) vs 102.1 (± 19.9) (p = 0.025)]. The subanalysis (69 patients) showed a statistically significant decrease in ISR before and after rTKA (p = 0.041), and from the native knee to post-rTKA (p = 0.001). There was a statistically significant decrease in BPR before and after rTKA (p = 0.001) and from the native knee to both pre- and post-rTKA (p < 001). CONCLUSION: After undergoing rTKA, the incidences of both patella baja (PB) and pseudo-patella baja (PPB) increased. Stiffness in the knee was associated with a higher incidence of PB, while non-stiffness cases showed a significantly higher incidence of PPB. Patients with stiff knees and PPB after rTKA experienced a significant reduction in range of motion (ROM). Additionally, the study revealed a noteworthy decrease in ISR and BPR with each subsequent surgery. This information is crucial for healthcare providers, as it sheds light on potential risks and outcomes of rTKA, allowing for improved patient management and surgical decision-making. LEVEL OF EVIDENCE: III.

A Suprapatellar Approach, When Compared With an Infrapatellar Approach, Yields Less Anterior Knee Pain and Better Patellofemoral Joint Function, for Intramedullary Nailing of Diaphyseal Tibial Fractures: Results of a Randomized Controlled Trial.

OBJECTIVES: To assess if a suprapatellar (SP) approach, when compared with an infrapatellar (IP) approach, yielded less patient-reported anterior knee pain and higher patellofemoral joint function at 6 weeks and 12 months postoperatively, when treating tibial fractures with intramedullary nailing. DESIGN: Prospective, parallel-group randomized control trial. SETTING: Tertiary level 1 trauma care center, Brisbane, Australia. PATIENTS SELECTION CRITERIA: Skeletally mature patients with an acute diaphyseal tibial fracture (AO/OTA 41A2/3, 42 A1-43A3) amenable to an intramedullary nailing were included. Exclusion criteria were periprosthetic fractures, nonunions, and presence of a contralateral injury that would restrict weight-bearing. OUTCOME MEASURES AND COMPARISONS: Anterior knee pain through the visual analog scale (VAS) and patellofemoral function using the Kujala scale at 6 weeks and 12 months were compared between those treated with a SP and IP approach. RESULTS: Ninety-five tibia fractures were included in the randomized trial, with complete follow-up data for 44 and 46 tibia fractures in the SP and IP groups, respectively. The SP cohort exhibited better patellofemoral knee function at both 6 weeks (Kajula 53.0 for SP vs. 43.2 for IP, P < 0.01) and 12 months (Kujala 92.0 for SP vs. 81.3 for IP, P < 0.01) postoperatively and a reduction in anterior knee pain at 12 months postoperatively (VAS 0.7 SP vs. 2.9 IP, P < 0.01). CONCLUSIONS: This randomized trial demonstrated clinically meaningful differences in patellofemoral function, for a SP versus IP approach, with a greater than 10 point discrepancy in Kujala score at both 6 weeks and 12 months. In addition, there was a clinically important difference in VAS knee pain scores for patients at 12 months, but not at 6 weeks, postoperatively. These results contribute to the growing body of evidence demonstrating the functional and clinical benefits of the SP approach. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Reconstruction of the medial patellofemoral ligament through a double bundle of a single patellar tract and quadriceps tendons combined with medial displacement of lateral hemi-tibial tuberosity for treating low-grade recurrent patella dislocation.

PURPOSE: The present study aimed to assess the clinical efficacy and imaging results of reconstruction of the medial patellofemoral ligament through a double bundle of single patellar tract and quadriceps tendons combined with medial displacement of lateral hemi-tibial tuberosity for treating low-grade recurrent patella dislocation. METHODS: Twenty-three patients with recurrent patellar dislocation, including ten males and 13 females, with 23 knee joints were enrolled according to the relevant criteria. Reconstruction of the medial patellofemoral ligament was performed through a double bundle of a single patellar tract and quadriceps tendons combined with medial displacement of lateral hemi-tibial tuberosity. Knee function was evaluated using visual analog scale (VAS) score, International Knee Documentation Committee (IKDC) score, Lysholm score, Tegner score, and Kujala score at pre- and postoperative stages. Patellar stability was assessed by CT scans measuring tibial tuberosity-trochlear groove (TT-TG) distance, lateral patella displacement (LPD), congruence angle (CA), and patellar tilt angle (PTA). RESULTS: All 23 patients were effectively followed up for 13-28 months (mean: 21.91 ± 4.14 months). At the last follow-up, the postoperative VAS score, IKDC score, Lysholm score, Tegner score, and Kujala score of 23 patients were 1.13 ± 0.82, 87.35 ± 3.17, 90.22 ± 1.28, 4.35 ± 0.65, and 89.26 ± 1.96, respectively, as compared to the preoperative values of 5.91 ± 1.13, 30.96 ± 5.09, 30.30 ± 2.98, 1.26 ± 0.62, and 27.87 ± 3.46, respectively, and these differences were statistically significant (P < 0.001). At the last follow-up, the postoperative TT-TG, LPD, CA, and PTA values of the 23 patients were 8.80 ± 1.85 mm, 6.01 ± 1.77 mm, 11.32 ± 6.18°, and 9.35 ± 2.88°, respectively, compared to the preoperative values of 18.77 ± 1.74 mm, 14.90 ± 4.07 mm, 37.82 ± 5.71°, and 23.58 ± 3.24°, respectively, and the differences were statistically significant (P < 0.001). No relevant complications were observed in the 23 patients. CONCLUSIONS: Reconstruction of the medial patellofemoral ligament through a double bundle of a single patellar tract and quadriceps tendons combined with medial displacement of lateral hemi-tibial tuberosity for treating low-grade recurrent patella dislocation showed satisfactory medium-term efficacy, and further investigations are required to confirm the long-term efficacy of this approach.

The Influence of Tibial Tubercle-Sparing Slope-Reducing Osteotomy on Patellar Height in Patients Undergoing Revision ACL Reconstruction.

BACKGROUND: A posterior tibial slope (PTS) >12° is an independent risk factor for anterior cruciate ligament (ACL) graft rupture, and a high tibial osteotomy (HTO) for slope correction can help avoid it. Management of patellar height is of major concern when performing HTO. PURPOSE: To evaluate the effect of tibial tubercle-sparing anterior closing-wedge osteotomy on patellar height in revision ACL reconstruction (ACLR). STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Patients who underwent arthroscopic revision ACLR combined with retro-tibial tubercle anterior closing-wedge HTO (ACW-HTO) between January 1, 2016, and March 31, 2021, were assessed for eligibility. Patellar height was measured on full weightbearing lateral radiographs according to the Insall-Salvati index (ISI) and Caton-Deschamps index (CDI) or frontal radiographs using the femoral patellar height index. The PTS was evaluated using the proximal anatomic axis of the tibia on standard short lateral radiographs. The delta (postoperative - preoperative) and the ratio (preoperative/postoperative) of the 3 patellar height indices and PTS were calculated. Preoperative and postoperative patellar heights were compared using independent t tests for each index. Also investigated was whether patients changed patellar height category (baja, normal, or alta) after slope osteotomy. RESULTS: Among 475 revision ACLRs, 47 tibial tubercle-sparing ACW-HTOs were retained for analysis. No significant difference in patellar height was found between pre- and postoperative radiographs regardless of the index (preoperative - postoperative) (ISI: 1.0 ± 0.2 - 0.9 ± 0.2, P = .1729; CDI: 1.0 ± 0.2 - 1.0 ± 0.2, P = .4034; femoral patellar height index: 1.5 ± 0.2 - 1.5 ± 0.2; P = .5130). Fifteen patients (31.9%) exhibited a postoperative change in their patellar height category when measured by the ISI (6 moved up a category, 9 moved down one), and 18 patients (38.3%) changed category according to the CDI (10 moved up a category, 8 moved down one). No significant difference was found between pre- and postoperative patellar height among these patients (ISI: P = .2418; CDI: P = .3005). CONCLUSION: Changes in patellar height ratio are common after tibial tubercle-sparing ACW-HTO in patients undergoing revision ACLR. The clinical effect of these changes is unknown, and further study is needed to investigate whether they may result in patellofemoral symptoms.

Treatment of Unfixable Inferior Pole Fractures of the Patella Using an All-Suture Internal Fixation Technique.

Inferior pole fractures of the patella are a type of patellar fracture that has various complexities. Most current techniques are associated with hardware-related complications, which is one of the main concerns when treating this complex fracture. We present a new technique that does not require metal implant removal, causes little to no irritation of the quadriceps muscle, and provides strong fixation that allows for early range of motion postoperatively.

Increased risk for early revision with quadriceps graft compared with patellar tendon graft in primary ACL reconstructions.

PURPOSE: Bone patella-tendon bone (BPTB) and hamstring tendon (HT) autografts are the most used grafts in primary anterior cruciate ligament (ACL) reconstructions (ACLR) in Norway. Quadriceps tendon (QT) autograft has gained more popularity during the past years. The purpose of this study is to compare revision rates and patient-reported outcomes of primary QT with BPTB and HT autograft ACL reconstructions in Norway at 2-year follow-up. It was hypothesized that there would be no difference in 2-year revision rates between all three autografts. METHODS: Data included primary ACLR without concomitant ligament surgeries, registered in the Norwegian Knee Ligament Register from 2004 through 2021. Revision rates at 2 years were calculated using Kaplan-Meier analysis. Hazard ratios (HR) for revision were estimated using multivariable Cox regression analysis with revision within 2 years as endpoint. Mean change in patient-reported outcome was recorded preoperatively and at 2 years through the Knee Injury and Osteoarthritis Outcome Score (KOOS) subcategories 'Sport' and 'Quality of Life' was measured for patients that were not revised and analysed with multiple linear regression. RESULTS: A total of 24,790 primary ACLRs were identified, 10,924 with BPTB, 13,263 with HT and 603 with a QT graft. Patients in the QT group were younger (23.5 years), more of them were women (58.2%) and over 50% had surgery <3 months after injury. The QT group had the highest prevalence of meniscal injuries (61.9%). Revision estimates at 2-years were 3.6%, 2.5% and 1.2% for QT, HT and BPTB, respectively (p < 0.001). In a Cox regression analysis with QT as reference, BPTB had a lower risk of revision (HR 0.4, 95% Cl 0.2-0.7, p < 0.001). No significant difference was observed in the revision risk between QT and HT (HR 1.1, 95% Cl 0.7-1.8, n.s.). The two most common reported reasons for revision were: traumatic graft rupture and nontraumatic graft failure. There were no differences between the groups in change of KOOS in subcategories 'Sport' and 'Quality of Life' at 2-years follow-up. CONCLUSION: The 2-year risk of revision after ACLR with QT was higher than BPTB and similar to HT. No difference was found between the groups in patient-reported outcomes. This study provides valuable insights for both surgeons and patients when making decisions about the choice of autografts in primary ACL reconstructions. LEVEL OF EVIDENCE: Level II.

Osteotomy Correction Angle Cut-off Points Can Guide the Operation to Prevent a Significant Decrease in Patella Height.

OBJECTIVE: Patients who undergo a biplanar ascending medial open-wedge high tibial osteotomy with an excessive correction angle might experience patella infera and even knee pain after surgery. The purpose of this study was to identify the cut-off points for the degree of knee varus correction of open-wedge high tibial osteotomy, which is related to the symptomatic patellar position change. METHODS: This retrospective study included 124 patients (mean age 61.69 ± 6.28 years; 78 women, 46 men) with varying degrees of varus knee osteoarthritis. All patients had undergone standard biplanar medial open-wedge high tibial osteotomy. They were divided into nine groups according to the change in hip-knee-ankle angle. Plain radiographs and three-dimensional CT images were obtained preoperatively and 18 months postoperatively. Patellar height was assessed using the Caton-Deschamps index, the Insall-Salvati index, and the Blackburne-Peel index. The patellofemoral index and patellar tilt were used to evaluate the degree of horizontal displacement of the patella. The varus correction, medial-proximal tibial angles, joint line convergence angles, and hip-knee-ankle angles were also measured. The subjective score was evaluated using the Western Ontario and McMaster Universities osteoarthritis index (WOMAC). RESULTS: There were significant changes in patella indexes in each group after surgery, among which there was no significant difference in patellar height changes for Groups A to F (p > 0.05), which were significantly lower than those in Group G, H, and I (p < 0.001). The patellar tilt and patellofemoral index also followed the same trend. The improvement in WOMAC scores for Groups G, H, and I was also significantly less for Groups A to F (p < 0.001). CONCLUSION: The patellar height, patellar tilt, and patellofemoral index all changed significantly in parallel with increasing degrees of osteotomy correction. The cut-off points for correction angle are 12.5° to 13.4°. When the correction angle is larger than this range, the patellar position can be significantly affected. Postoperative patellofemoral joint pain may be related to the changes in patella position.

Radiographic Investigation of Coronal Plane and Patellar Height and Changes Following Tibial Deflection Osteotomy for Correction of Tibial Slope in Combination With ACL Reconstruction.

BACKGROUND: A tibial deflexion osteotomy (TDO) is performed to decrease the sagittal tibial slope to reduce the relative risk of anterior cruciate ligament (ACL) reconstruction (ACLR) graft failure. Given that coronal plane osteotomies can cause consequential changes in the sagittal plane to patellar height and tibial slope, potential changes to coronal plane alignment and patellar height can result after a sagittal plane osteotomy. PURPOSE: To compare preoperative and postoperative coronal plane alignment after TDO, as well as to analyze the effect of the osteotomy on patellar height. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: This study was conducted on a consecutive series of patients with primary and revision ACLR with concomitant TDO between 2011 and 2022. Inclusion criteria were 1-stage autograft ACLR combined with supratubercular TDO with pre- and 3 months postoperative radiographs of sufficient quality. Indications for TDO were anterior instability requiring ACL revision surgery and a posterior tibial slope (PTS) >9° or a PTS >14° in the primary ACL surgery patients. Anteroposterior and lateral knee radiographs were reviewed, and the medial proximal tibial angle (MPTA), PTS, Caton-Deschamps index (CDI), and modified Insall-Salvati ratio were measured directly from the radiographs by 2 independent reviewers. RESULTS: A total of 68 patients were included in this study. Pre- and postoperative radiographs were performed 1 month before and 3 months after surgery, respectively. There was a significant increase in the mean MPTA of 0.95° varus (SD, 2.1°; range, increase of 4.23° valgus to increase of 7.74° varus; P < .01), a decreased PTS of 8.86° (SD, 3.03°; P < .01), and an increased CDI of 0.08 (range, decrease of 0.27 to increase of 0.64) (P < .01; SD, 0.17) in patients undergoing TDO. Insall-Salvati ratio measurements showed no difference. There was good intra- and interobserver reliability, with intraclass correlation coefficients of 0.97 and 0.91 for MPTA, 0.97 and 0.87 for PTS, 0.87 and 0.93 for CDI, and 0.88 and 0.76 the Insall-Salvati ratio. CONCLUSION: This study, the largest series on TDO for ACLR, demonstrates that the TDO can be performed safely without large changes to coronal alignment or patellar height. The tibial slope was reduced by a mean of 8.86° (range, 2.3°-11.5°; P < .01). The TDO produces a small statistically significant change to coronal alignment, inducing a mean increased varus of <1° and an increased patellar height of 0.1 CDI. Therefore, TDO can be performed safely without dramatic changes to coronal alignment or patellar height, this study highlights technical aspects to minimize iatrogenic varus.

Editorial Commentary: Biplanar Medial Opening-Wedge High Tibial Osteotomy: A Retrotubercular Technique Changes the Patellofemoral Alignment Less Than a Supratubercular Technique but May Increase the Tibial Slope and Complication Rates.

An opening-wedge high tibial osteotomy may be performed with a uniplanar cut, usually passing proximal to the tibial tubercle, or a biplanar cut, with the anterior part of the cut passing either proximal to the tibial tubercle (an ascending anterior or supra-tubercular biplanar osteotomy) or distal to the tibial tubercle (a descending anterior or retrotubercular biplanar osteotomy). A retrotubercular osteotomy maintains the patellofemoral alignment, whereas a supratubercular osteotomy can decrease the patellar height and lateralize the tibial tubercle. However, maintaining the patellofemoral alignment may not translate to a clinical benefit, and a retrotubercular technique is technically more difficult, has the potential to increase the posterior tibial slope, and confers an increased risk of complications.

Different modalities of patellar management in primary total knee arthroplasty: a Bayesian network meta-analysis of randomized controlled trials.

BACKGROUND: The primary management modalities for the patella in TKA include patellar resurfacing, patellar non-resurfacing, patellar resurfacing with denervation, and patellar non-resurfacing with denervation. Traditionally, meta-analyses have predominantly focused on examining comparisons between two management modalities. However, this study performed a network meta-analysis to compare all four patellar management interventions to identify the most optimal approach for patellar management in TKA. METHODS: A computer-based search of PubMed, China National Knowledge Infrastructure (CNKI), The Cochrane Library, Web of science, Embase, and MEDLINE databases was performed to identify randomized controlled trials focusing on the four management interventions for the patella in TKA. Comparisons included two-by-two comparisons as well as those involving more than two concurrent comparisons. The search timeframe spanned from inception to June 30, 2023. Two independent authors extracted the data and evaluated the quality of the literature. The Cochrane Collaboration Risk of Bias (ROB) tool was used to evaluate the overall quality of the literature. Subsequently, a network meta-analysis was conducted using the "gemtc" package of the R-4.2.3 software. Outcome measures such as anterior knee pain (AKP), reoperation rate, and patient satisfaction rate were evaluated using odd ratio (OR) and 95% confidence intervals (CI). Additionally, the knee society score (KSS), function score (FS), and range of motion (ROM) were evaluated using mean differences (MD) with associated 95% CI. The different treatment measures were ranked using the surfaces under the cumulative ranking curves (SUCRA). RESULTS: A total of 50 randomized controlled trials involving 9,283 patients were included in the analysis. The findings from this network meta-analysis revealed that patellar resurfacing exhibited significantly lower postoperative reoperation rate (OR 0.44, 95% CI 0.24-0.63) and AKP (OR 0.58, 95% CI 0.32-1) compared to non-resurfacing. Additionally, patellar resurfacing exhibited higher postoperative KSS clinical scores in comparison with non-resurfacing (MD: 1.13, 95% CI 0.18-2.11). However, for postoperative FS, ROM, and patient satisfaction, no significant differences were observed among the four management interventions. CONCLUSION: Patellar resurfacing emerges as the optimal management modality in primary TKA. However, future studies should aim to reduce sources of heterogeneity and minimize the influence of confounding factors on outcomes. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023434418 identifier: CRD42023434418.

Comparative study of locking neutralization plate construct versus tension band wiring with a cannulated screw for patella fractures: experimental and finite element analysis.

Transverse patella fractures, accounting for approximately 1% of Orthopedic injuries, pose intricate challenges due to their vital role in knee mechanics. This study aimed to compare the biomechanical performance of a construct, integrating cannulated screws and an anterior locking neutralization plate, with the conventional tension band wiring technique for treating these fractures. Experimental testing and Finite Element Analysis were employed to evaluate the constructs and gain profound insights into their mechanical behavior. Sixteen cadaveric knees were prepared, and transverse patella fractures were induced at the midpoints using a saw. The plate construct and tension band wire fixation were randomly assigned to the specimens. A cyclic test evaluated the implants' durability and stability, simulating knee movement during extension and flexion. Tensile testing assessed the implants' maximum failure force after cyclic testing, while Finite Element Analysis provided detailed insights into stress distribution and deformation patterns. Statistical analysis was exclusively performed for the experimental data. Results showed the plate enhanced stability with significantly lower deformation (0.09 ± 0.12 mm) compared to wire fixation (0.77 ± 0.54 mm) after 500 cycles (p = 0.004). In tensile testing, the construct also demonstrated higher failure resistance (1359 ± 21.53 N) than wire fixation (780.1 ± 22.62N) (p = 0.007). Finite Element Analysis highlighted distinct stress patterns, validating the construct's superiority. This research presents a promising treatment approach for transverse patella fractures with potential clinical impact and future research prospects. This study presents a promising advancement in addressing the intricate challenges of transverse patella fractures, with implications for refining clinical practice. The construct's improved stability and resistance to failure offer potential benefits in postoperative management and patient outcomes.

[Patellar tracking in knee arthroplasty]. / Patellatracking in der Knieendoprothetik.

Knee arthroplasty is a demanding procedure that, when carried out appropriately, results in significant pain relief and patient satisfaction. The success of the operation is influenced by many factors. The most important ones describe the implant design, the orientation of the components and the ligament tension. The patellofemoral joint is often neglected as an important part of the operation. Initially, complications in the area of the patellofemoral joint do not appear to be devastating, but in many cases, they lead to significant consequences for the patient, along with severe pain and limited mobility. The most common complications arise from patellar maltracking. This often occurs due to misplacement of the tibial and femoral components and the altered shape of the patella. If the placement of the components with regard to patellar tracking is considered, bony and/or soft tissue addressing measures remain to further optimize the movement of the patella. The following manuscript is dedicated to discussing causes to avoid patellar maltracking and improve clinical outcomes.

Results of a Highly Porous Metal-Backed Cementless Patella Implant: A Minimum 5-Year Follow-Up.

Initial design cementless metal-backed patellar implants failed due to multiple reasons including implant design, use of first-generation polyethylene, and surgical technique. This study evaluates clinical outcomes and survivorship of total knee arthroplasty (TKA) using a current generation highly porous metal-backed patellar component. One-hundred twenty-five consecutive primary cementless TKAs with a compression molded highly porous metal-backed patella were reviewed. One-hundred three TKAs (82.4%) with 5-year clinical and radiographic follow-up were available for review. These were matched with 103 consecutive TKAs using a cemented patella of the same implant design. The cementless cohort had a mean age of 65.5 years, body mass index (BMI) of 33.0, and follow-up of 64.4 months. Indications for cementless TKA were based on multiple factors including age, BMI, and bone quality. There were no revisions for loosening or mechanical failure of the cementless patella compared with two cemented patellae revised for aseptic loosening. Eight patients required revisions in the cementless cohort: three for prosthetic joint infection (PJI), two for instability, one periprosthetic femur fracture, one for patella instability, and one for extensor mechanism rupture. Five patients required revisions in the cemented cohort: two for aseptic patellar loosening, one for aseptic femoral loosening, one for PJI, and one for instability. All-cause survivorship at 5 years was 92.2 and 95.1% for the cementless metal-backed implant and cemented implant cohorts, respectively. Use of a compression molded highly porous metal-backed patella component demonstrated excellent clinical and radiographic results at 5-year follow-up. Longer follow-up is required to evaluate the ability of highly porous cementless patella implants to provide durable long-term fixation.

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. 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.

Tourniquet-free minimally invasive total knee arthroplasty is associated with early aseptic loosening.

BACKGROUND: While tourniquet-free (T-) total knee arthroplasty (TKA) has gained popularity, tourniquet-use during minimally-invasive (MIS)-TKA has not been adequately studied. Traditional techniques employ knee hyper-flexion, compressing vasculature and reducing impact of bleeding, while MIS-TKA embraces the semi-extended knee position, which does not restrict the effects of bleeding on cementation and visualization. We compared the risk of aseptic loosening between patients undergoing T- MIS-TKA compared to T + MIS-TKA. METHODS: This single-surgeon cohort study included 329 consecutive MIS-TKA (226 T+,103 T-) patients with minimum 3-year follow-up. Aseptic loosening, radiolucent lines (RLL), health related quality of life scores, and complications were recorded. T-test and chi-square test were used to compare continuous and categorical variables, and logistic regression included BMI, age, ASA, patellar-resurfacing, and tourniquet-use. RESULTS: There were no differences in baseline demographics. One (0.4 %) aseptic loosening occurred with T+, versus 7 (6.8 %) with T- (p = 0.002). No T + and 3 T- patients (2.9 %, p = 0.01) had revision for aseptic loosening. The incidence of RLLs was 16.8 % in T + and 30.1 % in T- (p = 0.008). Logistic regression revealed T + was significantly associated with decreased aseptic loosening and risk of RLL (odds ratio = 16.4, odds ratio = 2.8). CONCLUSION: In this consecutive series, T- MIS-TKA was associated with increased rates of revision for aseptic loosening as compared to the T + MIS-TKA, even controlling for BMI, age, ASA level, and patellar resurfacing. Radiolucent lines were increased with T- MIS-TKA compared to T + MIS-TKA. Complications, all-cause revision, ROM, and HRQoL scores were similar between tourniquet-use and tourniquet-free cohorts.

Effect of ascending and descending medial open wedge high tibial osteotomy on patella height and functional outcomes-a retrospective study.

BACKGROUND: High tibial osteotomy (HTO) is a popular joint-preserving option for medial compartmental osteoarthritis. However, this is associated with alterations in the patellar height (PH) and tibial slope (TS). This study aims to compare the effect of ascending (AMHTO) and descending medial opening wedge HTO (DMHTO) on patella height, posterior tibial slope and functional outcomes. MATERIAL AND METHODS: A retrospective study was conducted between February 2018 and July 2021. Patients with medial compartment osteoarthritis, varus alignment, and complete pre- and postoperative lateral and full-length anteroposterior radiographs were included. Pre- and postoperative radiological measurements include the Caton-Deschamps index (CDI), the mechanical axis deviation (MAD), and the posterior tibial slope. The functional outcomes were measured using the Oxford Knee Score (OKS), Lysholm Knee Score (LKS), and Tegner Activity Scale (TAS). The osteotomy union was checked with serial X-rays every 6 weeks till a satisfactory union was achieved. RESULTS: Fifty-eight patients were included in the study. Thirty-four (58%) patients received AMHTO, and 24 (42%) received DMHTO. There was no baseline difference in the demographic variables or functional scores between the two groups. The preoperative mean MAD of - 9.65° ± 3.67° was corrected significantly to + 0.08 ± 2.80° (varus -, valgus + , P = 0.034). A significant difference in preoperative and postoperative CDI of 0.93 ± 0.45 and 0.83 ± 0.27, respectively, was noted (P = 0.023). In the AMHTO group, a statistically significant decrease in PH from preoperative 1.03 ± 0.77 to 0.84 ± 0.12 was noted (P = 0.003). There was a significant improvement in functional outcomes between baseline and 9-month follow-up in both groups. There was no significant difference between the functional outcomes of the two groups at 9-month follow-up. CONCLUSION: The study confirmed our hypothesis that descending HTO caused less alteration in the patella height compared to ascending HTO. There is no significant difference in the functional outcomes between the groups. However, in patients with PFOA, and when attempting higher degree of correction through AMHTO, the possibility of worsening of symptoms due to change in PH must be considered.