Patellar Fracture Research Articles

PATELLA FRACTURES, EPIDEMIOLOGY, ANATOMY, FUNCTION, MECHANISMS OF ACTION, CLASSIFICATION, CLINICAL PRESENTATION, IMAGING PRESENTATION, TREATMENT AND COMPLICATIONS

Introduction: The patella has a great importance in the extension and flexion activities of the knee, being paramount in the patient's quality of life. Nowadays the surgical options that stand out the most are open reduction plus internal fixation and resection of the patella. The patella increases the leverage of the quadriceps. Management following patella injury has been based on preservation of bone and vascular supply, in addition to joint restoration and extensor function. In patella fractures, it is essential to reflect on the biomechanics of the bone and the fixation technique to be used. Objective: to detail the current information related to patella fractures, epidemiology, anatomy, function, mechanisms of action, classification, clinical presentation, imaging presentation, treatment and complications. Methodology: a total of 32 articles were analyzed in this review, including review and original articles, as well as clinical cases, of which 24 bibliographies were used because the other articles were not relevant for this study. The sources of information were PubMed, Google Scholar and Cochrane; the terms used to search for information in Spanish, Portuguese and English were: patella, patellar fractures, knee trauma. Results: Patellar fractures comprise 1% of all fractures in humans, with a 2:1 male to female ratio. They occur more frequently in individuals between 20 and 50 years of age. The frequencies of pseudarthrosis and infection are relatively lower after the surgical procedure. Approximately 2 to 7% of patellar fractures are open fractures. Their classification is descriptive. Conclusions: The patella is the largest sesamoid bone in the human body with several important functions. Frequently, patellar fractures appear after falls on the knee, blows and unexpected and energetic muscular pulls. The diagnosis is made by means of clinical history, physical examination and complementary radiography. Anteroposterior and lateral projections of the knee should be performed. For conservative treatment it is essential that the knee extensor mechanism is intact. There are several methods of surgical treatment, in general the open reduction and internal fixation present good results. Complications include post-traumatic osteoarthritis, alteration or loss of mobility of the knee, refracture, fixation failure, osteonecrosis, intolerance to osteosynthesis material, loss of strength of the extensor mechanism, loss of extension, instability of the patella and pseudoarthrosis. KEY WORDS: patella, knee, fracture, treatment, osteosynthesis.

Anterior hook plating of patella fractures: A biomechanical analysis and clinical series.

Compare anterior hook plating to established fixation constructs biomechanically and report outcomes and complications in a cohort of patella fractures treated with the technique. Lab based biomechanical study and clinical multicenter retrospective cohort study. Two US level one trauma centers.Patients/Participants: 51 patients (28M, 23F) with 30 simple transverse and 21 comminuted patella fractures. 36 cadaveric patellae for the biomechanical study. Biomechanical- Compared dorsal plating with cerclage wiring and modified tension band cable fixation in a comminuted patella fracture model in 36 cadaveric patellae. Constructs were tested in 0° and 45° of flexion. Clinical - We reviewed a consecutive series of patella fractures in two centers for outcome and complications. Biomechanical - construct stiffness. Clinical - reduction, union, complications, range of motion. Stiffness greatest in dorsal plating in both 0° and 45°. Dorsal plating (976 N, 1643 N) > modified tension band (317, 297) > cerclage (89.8, 150.3). 51 patients with patella fractures fixed with dorsal 2.7 mm mini-fragment plates including a distal to proximal lag screw through the plate from the nose of the patella. 9 Cases were small distal fragments not easily managed with screws and cables. All patients were followed to union. There were 2 infections (1 superficial, 1 deep with nonunion) and 5 had hardware removal (9.8%). Dorsal plating is biomechanically and clinically superior to modified tension band and cerclage techniques in comminuted patella fractures. This method allows for fixation of small distal pole fractures.

Intraoperative Fractures Sustained During Total Knee Arthroplasty: A Critical Analysis Review.

» While the occurrence of postoperative periprosthetic fractures around total knee arthroplasties (TKAs) are well reported, little is known about intraoperative fractures that occur during TKA. Intraoperative fractures during TKA can occur in femur, tibia, or patella. It is a rare complication with an incidence of 0.2% to 4.4%.» Risk factors of periprosthetic fractures include osteoporosis, anterior cortical notching, chronic corticosteroid use, advanced age, female sex, neurologic disorders, and surgical technique.» Fractures can potentially occur at any stage of the TKA including exposure, bone preparation, placement of trial components, cementation, insertion of the final components, and seating of the polyethylene insert. Forced flexion during trialing increases the risk for patella fracture, tibial plateau, or tubercle fractures especially when there is under resection of the bone.» Management guidelines for these fractures are lacking with current options being observation, internal fixation, the use of stems and augments, increasing constraint of the prosthesis, implant revision, and modifying the postoperative rehabilitation.» Finally, the outcomes of intraoperative fractures are not well reported in the literature.

Biomechanical Evaluation of Transverse Patella Fracture Fixation using Headless Screws: A Comparison of Suture vs. Cable as a Tension Band.

To explore the performance of headless screws with FiberWire Suture as a tension band and headless screws with a mini-cable tension band in patella fixation. A transverse osteotomy was created in six matched pairs of fresh-frozen cadaver knee joints. One knee was randomly assigned to receive fixation with headless screws plus a cable tension band (Synthes 1.3 mm cable with crimp), while the other was fixed with headless screws plus a suture tension band (#5 FiberWire). Using a servo-hydraulic material testing system, the specimens were first tested non-destructively under 20% of the reported mean failure load with standard technique of cannulated screws with tension band wiring. The specimen was then loaded to 1000 N to test the construct's failure strength. All tests were run under displacement-control with loading threshold. A motion analysis system was used to track the interfragmentary motion to assess fixation stability. The correlation between fixation strength and score of bone density was also examined. In the non-destructive loading test, gap displacement under 150N was 0.10 mm or less for 11 of 12 specimens, and the difference between the two groups was not statistically significant. In the destructive test, 3 of 12 specimens maintained reduction (gap<2mm) at the maximum load of 1000 N. Of the failed specimens, the mean strength was 648±185 N for suture and 784±228 N for cable (p=0.24). Regression analysis shows bone density was associated with the failure load of the tendon (R2=0.43, p=0.02). There was no significant difference in fixation strength or sub-failure fragment displacement between the suture and cable tension band techniques when using headless screws, but suture on average was weaker.

Adjunct neutralization plating in patella fracture fixation: a technical trick-Erratum.

Adjunct neutralization plating in patella fracture fixation: a technical trick-Erratum.

Patellar Tracking: An Old Problem with New Insights.

Patellofemoral pain and instability are common indications for imaging that are encountered in everyday practice. The authors comprehensively review key aspects of patellofemoral instability pertinent to radiologists that can be seen before the onset of osteoarthritis, highlighting the anatomy, clinical evaluation, diagnostic imaging, and treatment. Regarding the anatomy, the medial patellofemoral ligament (MPFL) is the primary static soft-tissue restraint to lateral patellar displacement and is commonly reconstructed surgically in patients with MPFL dysfunction and patellar instability. Osteoarticular abnormalities that predispose individuals to patellar instability include patellar malalignment, trochlear dysplasia, and tibial tubercle lateralization. Clinically, patients with patellar instability may be divided into two broad groups with imaging findings that sometimes overlap: patients with a history of overt patellar instability after a traumatic event (eg, dislocation, subluxation) and patients without such a history. In terms of imaging, radiography is generally the initial examination of choice, and MRI is the most common cross-sectional examination performed preoperatively. For all imaging techniques, there has been a proliferation of published radiologic measurement methods. The authors summarize the most common validated measurements for patellar malalignment, trochlear dysplasia, and tibial tubercle lateralization. Given that static imaging is inherently limited in the evaluation of patellar motion, dynamic imaging with US, CT, or MRI may be requested by some surgeons. The primary treatment strategy for patellofemoral pain is conservative. Surgical treatment options include MPFL reconstruction with or without osseous corrections such as trochleoplasty and tibial tubercle osteotomy. Postoperative complications evaluated at imaging include patellar fracture, graft failure, graft malposition, and medial patellar subluxation. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Characterization of Oral Pathology in Cats Affected by Patellar Fracture and Dental Anomaly Syndrome (PADS).

Patellar fracture and dental anomaly syndrome (PADS) is a congenital bone disease of cats that is characterized by atraumatic bone fractures (most commonly the patella), the persistence of deciduous teeth, and impaction of permanent teeth. Jaw swelling due to osteomyelitis is often the reason that cats with PADS are presented for veterinary dental care. The clinical history, oral examination findings, dental radiological findings, and histopathology were evaluated for 13 cats with dental and skeletal pathology consistent with PADS, including 9 with osteomyelitis. Cats in this study were predominantly domestic shorthair (12 of 13 cats), and there was no apparent sex predilection. All cats had multiple persistent deciduous teeth and multiple impacted permanent teeth, although the number of persistent and impacted teeth varied. Osteomyelitis of the jaw typically occurred within the first 4 years of life. Osteomyelitis of the mandible was 4 times more common than osteomyelitis of the maxilla. Histologically, osteomyelitis was chronic, neutrophilic, and osteoproliferative. Necrotic bone was confirmed in 67% of osteomyelitis lesions. Histological evaluation of jaws without inflammation demonstrated abnormal amounts of unmodeled bone, abnormally dense bone, and retention of cartilage in the caudal mandible. Three cats in the study had mandibular distoclusion and 2 had concurrent paronychia. To obtain a favorable clinical outcome in PADS cats with jaw swelling, prompt and aggressive surgical treatment of osteomyelitis is required. Extraction of persistent deciduous teeth and impacted permanent teeth is recommended when there is associated periodontitis or osteomyelitis.

A novel patella fracture fixation technique: finite element analysis.

Patella fractures account for approximately 1% of all bone fractures. The tension band wiring technique has been used in surgical treatment. However, there is no clear information about the location of the K-wires in sagittal plane. Thus, a transverse fracture line was created in the patella finite element model and fixed with Kirchner (k) wires and cerclage at different angles and compared with two different standard tension band models. A total of 10 finite element models were created to study AO/OTA 34-C1 patella fractures. Two models used the classical tension band method with either circumferential or 8-shaped cerclage wire. The other 8 models used K-wires placed at 45° or 60°, either alone or combination with cerclage wire. A force of 200N, 400N, and 800N were applied at 45° knee angle and the resulting data fracture line opening, surface pressure and stress in the implants were analyzed through finite element analysis. When all the results are considered, it was determined that the K-wires 60° crossing at the fracture line and with cerclage modeling was superior to the other models. The diagonal placement of the K-wires with cerclage (could be 45° or 60° medium) was superior to the reference models. This study has shown that the new fixation method we propose could come to the fore as an alternative method to be used successfully in transverse patella fractures and lower complications. In transverse patellar fractures, the use of K-wires crossed at 60° may be a good alternative to the standard method.

Management and Outcome of Elderly Patients With Patellar Fracture Treated With Novel Modified Cerclage Wiring.

The purpose of this study is to assess the efficacy and security of a fixation method for fixing patellar fractures in elderly patients utilizing modified cerclage wire. From January 2015 to December 2020, 31 cases (age≥65years old) of closed patellar fracture were treated by modified cerclage wiring. Patients in these instances ranged in age from 65 to 87 (73.7 ± 7.2years), with 15 men and 16 women. 4 instances were type 34-C1 (transverse fracture) according to the AO/OTA classification, 27 cases (87%) were comminuted fractures, including 11 cases that were type 34-C2 (3 fragments), and 16 cases that were type 34-C3 (more than 3 fragments). Postoperative problems such as fragment re-displacement, nonunion, internal fixation loosening, infection, and internal fixation rupture were evaluated. The clinical grading systems of Böstman were used to assess the postoperative clinical outcomes. Thirty one patients in all were monitored for 14 to 31months (22.2 ± 4.5months). After the procedure, the fracture took 2.5-3.5months (2.92 ± .25months) to heal. There were no postoperative issues like infection, dislocation, implant breakage, uncomfortable hardware, or post-traumatic osteoarthritis. According to the clinical grading scales of Böstman, the average score of the final follow-up was 28.6 ± 1.1 (range 26-30). 29 (94%) of the patients had excellent results, whereas just 2 (6%) had good results. The patient's knee flexion activity ranged from 110 to 140°, making for a favorable prognosis. Most patella fractures in the elderly are comminuted. Elderly patients with patellar fractures may be successfully treated with modified cerclage wire, with good results and no noticeable side effects.

Achieving Rapid Healing and Low Complication Rates in Patellar Fracture Fixation: The Benefits of Cerclage and Figure-of-Eight Configuration.

Background and objective Patellarfractures account for around 1% of all fractures. Conservative treatment is advised in patients without any incompatibility of articular surfaces or those with intact extensor mechanisms. More than a 2-mm articular gap due to fracture warrants surgical intervention. Tension band wiring (TBW) is a commonly used practice for fixation, However, there is still controversy about its effectiveness and complications arising due to the hardware. Modification of this technique by using K-wires has been considered a method of choice, but this technique is associated with complications due to K-wires. The Pyrford technique is a method for patellar fracture fixation by circumferential cerclageand anterior TBW. We employed the figure-of-eight configuration over the circumferential wire. This study aimed to analyze the outcomes ofTBW of the patella without K-wires by assessing the rate of complication and functional outcomes. Materials and methods A total of 38 patientswithOTA 34C type, simple and comminuted type of patella fractures aged between22 and 70 years were treated with circumferential cerclage and figure-of-eight TBW.All patients underwent patellar fixation with cerclage and through direct purchase of SS wire via quadriceps and patellar tendon. Patients were followed up for one to three years. We analyzed differences in the range of motion, fracture reduction, fracture healing time, Bostman score for knee function, and complications. Results The mean age of the patients was 45 years. After TBW without K-wires, fracture healing and functional outcomes were satisfactory according to patient feedback and clinocoradiological examinations. Of note, 35 out of 38 patients (92%) had gained up to 90 degrees of active flexion at the end of one week. One patient (2.42%) developed a superficial infection. All fractures had achieved union at the end of 16 weeks. Malunion or nonunion was not noted in any of the cases. There was no case of implant removal. The average Bostman score at the 12-month follow-up was 28.5 ±1.5. The incidence of complications due to K-wire was nullified. Conclusion Based on our findings, the described method leads to better functional outcomes, decreasing hardware-related complications, and can be used in simple as well as comminuted fractures. The fracture healing and functional outcomes and rate of complications were satisfactory.

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

The aims of the surgical treatment are the anatomical reduction of the articular surface and stabilization of amultifragmentary patella fracture with a distal pole fragment using plate osteosynthesis and additive suture tape cerclage to secure the distal fragment. Demonstration of the surgical procedure for amultifragmentary patella fracture in the knee joint of a male cadaver. 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, asuture 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. Functional postoperative treatment with hard shell orthesis with movement limitation (30°, 60° and 90° for 2weeks each) and partial weight bearing of 15-20 kg for 6weeks is recommended. Full weight-bearing is only allowed in full extension. Plate osteosynthesis is biomechanically superior in comparison to the widely used tension band osteosynthesis. In multifragmentary fractures, additional augmentation with asuture tape cerclage seems to be appropriate. Due to the lack of study results there is currently no clinical evidence for this.

Most Fractures Treated Nonoperatively in Individuals With Fibrodysplasia Ossificans Progressiva Heal With a Paucity of Flareups, Heterotopic Ossification, and Loss of Mobility.

Fibrodysplasia ossificans progressiva (FOP) is an ultrarare genetic disorder with episodic and progressive heterotopic ossification. Tissue trauma is a major risk factor for flareups, heterotopic ossification (HO), and loss of mobility in patients with FOP. The International Clinical Council on FOP generally recommends avoiding surgery in patients with FOP unless the situation is life-threatening, because soft tissue injury can trigger an FOP flareup. Surprisingly little is known about flareups, HO formation, and loss of mobility after fractures of the normotopic (occurring in the normal place, distinct from heterotopic) skeleton when treated nonoperatively in patients with FOP. (1) What proportion of fractures had radiographic evidence of union (defined as radiographic evidence of healing at 6 weeks) or nonunion (defined as the radiographic absence of a bridging callus at 3 years after the fracture)? (2) What proportion of patients had clinical symptoms of an FOP flareup because of the fracture (defined by increased pain or swelling at the fracture site within several days after closed immobilization)? (3) What proportion of patients with fractures had radiographic evidence of HO? (4) What proportion of patients lost movement after a fracture? We retrospectively identified 36 patients with FOP from five continents who sustained 48 fractures of the normotopic skeleton from January 2001 to February 2021, who were treated nonoperatively, and who were followed for a minimum of 18 months after the fracture and for as long as 20 years, depending on when they sustained their fracture during the study period. Five patients (seven fractures) were excluded from the analysis to minimize cotreatment bias because these patients were enrolled in palovarotene clinical trials (NCT02190747 and NCT03312634) at the time of their fractures. Thus, we analyzed 31 patients (13 male, 18 female, median age 22 years, range 5 to 57 years) who sustained 41 fractures of the normotopic skeleton that were treated nonoperatively. Patients were analyzed at a median follow-up of 6 years (range 18 months to 20 years), and none was lost to follow-up. Clinical records for each patient were reviewed by the referring physician-author and the following data for each fracture were recorded: biological sex, ACVR1 gene pathogenic variant, age at the time of fracture, fracture mechanism, fracture location, initial treatment modality, prednisone use at the time of the fracture as indicated in the FOP Treatment Guidelines for flare prevention (2 mg/kg once daily for 4 days), patient-reported flareups (episodic inflammatory lesions of muscle and deep soft connective tissue characterized variably by swelling, escalating pain, stiffness, and immobility) after the fracture, follow-up radiographs of the fracture if available, HO formation (yes or no) as a result of the fracture determined at a minimum of 6 weeks after the fracture, and patient-reported loss of motion at least 6 months after and as long as 20 years after the fracture. Postfracture radiographs were available in 76% (31 of 41) of fractures in 25 patients and were independently reviewed by the referring physician-author and senior author for radiographic criteria of fracture healing and HO. Radiographic healing was noted in 97% (30 of 31) of fractures at 6 weeks after the incident fracture. Painless nonunion was noted in one patient who sustained a displaced patellar fracture and HO. In seven percent (three of 41) of fractures, patients reported increased pain or swelling at or near the fracture site within several days after fracture immobilization that likely indicated a site-specific FOP flareup. The same three patients reported a residual loss of motion 1 year after the fracture compared with their prefracture status. HO developed in 10% (three of 31) of the fractures for which follow-up radiographs were available. Patient-reported loss of motion occurred in 10% (four of 41) of fractures. Two of the four patients reported noticeable loss of motion and the other two patients reported that the joint was completely immobile (ankylosis). Most fractures treated nonoperatively in individuals with FOP healed with few flareups, little or no HO, and preservation of mobility, suggesting an uncoupling of fracture repair and HO, which are two inflammation-induced processes of endochondral ossification. These findings underscore the importance of considering nonoperative treatment for fractures in individuals with FOP. Physicians who treat fractures in patients with FOP should consult with a member of the International Clinical Council listed in the FOP Treatment Guidelines ( https://www.iccfop.org ). Level IV, therapeutic study.

INTERNAL FIXATION OF TRANSVERSE PATELLA FRACTURES USING CANNULATED CANCELLOUS SCREWS WITH ANTERIOR TENSION BAND WIRING: A PROSPECTIVE STUDY

Background: Patella fractures accounts for about 1% of all fractures. Modied tension band wiring using two parallel kirschner wires through patella and anterior tension band loop with stainless steel wire as treatment of displaced transverse patella fracture but has been reported with complications, use of cannulated screws cause less irritation to the soft tissues, provides a stable xation with compression at the fracture site. Materials and Method: This is a prospective study of 35 cases of displaced transverse patella fractures treated by internal xation using cannulated cancellous screws with anterior tension band wiring done from July 2020 to June 2022 at our Institution and followed for 1 year. Results: Road trafc accident was main mechanism of injury. Radiological union was achieved in 91.4% by the end of 13 weeks. In our study we observed that 54.3% patients had good outcome, 40.0% patients had excellent outcome and 5.7% patients had unsatisfactory outcome according to Bostman knee scoring system. Cannulated cancellous screws with gure of eight Conclusion: tension band wiring is safe and reliable for management of displaced transverse patella fractures with good functional outcome as union is faster and full range of motion is achieved early. It also has less chance of implant failure and soft tissue irritation

Biomechanical evaluation of three fixation methods in a feline transverse patella fracture model.

This study aimed to compare the biomechanical properties of three stabilisation techniques in feline patella transverse fractures and select the strongest method with potentially minimal complications. Patella fracture was simulated in 27 feline cadaveric pelvic limbs (mean weight of the cadavers 3.78 kg), and the limbs were randomly grouped to be stabilised with one of the three stabilisation methods. The modified tension band wiring technique with a single Kirschner wire (0.9 mm) and figure-of-eight wiring (20 G) was applied to group 1 (n = 9). Group 2 (n = 9) was stabilised with a combination of circumferential and figure-of-eight wiring techniques with orthopaedic wire (20 G). Group 3 (n = 9) was stabilised with the same technique as group 2, but with #2 FiberWire. The knee joints were positioned and fixed in the neutral standing angle (135°) and tested by applying tensile force. The loads at gap formations of 1, 2 and 3 mm were recorded, and the maximum failure load was measured in each group. In all the loads at displacement (1, 2 and 3 mm), group 3 was significantly stronger than groups 1 and 2, respectively (P <0.017). Group 3 (261.0 ± 52.8 N) showed significantly stronger fixation in the maximum load compared with group 1 (172.9 ± 45.6 N) (P <0.017). No significant difference was observed between groups 1 and 2 (204.9 ± 68.4 N) or between groups 2 and 3. This study shows that the combination of circumferential and figure-of-eight techniques with FiberWire is more resistant to displacement than metal wire in this ex vivo feline patella fracture model.

Patella component diameters of 38 mm and up might be associated with higher revision rates after patella resurfacing

PurposePatellar resurfacing is considered the standard of care for total knee arthroplasty in the USA. Complications of patella resurfacing include aseptic loosening or patella fractures and can threaten the integrity of the extensor mechanism. The goal of this study was to report on patella button revision rates in posterior stabilized total knee arthroplasty.Material and methodsBetween 01/2010 and 08/2016 patella buttons were implanted in 1056 patients (267 men and 550 women) as part of a posterior stabilized total knee arthroplasty.ResultsOf 1056 cases, 35 cases (14 women, 15 men, 5 bilateral, 3.3%) showed early loosening at a mean 52.5 months postoperatively. Patella components of 38 mm or larger diameters showed a significantly higher loosening rate than the 29, 32, 35 mm buttons (p < 0.01). Mean BMI of patients identified with aseptic loosening was 31.7 kg/m2, mean age at time of revision surgery was 63.3 years. All of the patients with loosening of the patella button required revision surgery; in 33 cases an exchange of the button was performed, in two cases a removal of the button and patellar bone grafting was indicated. No complications occurred after revision surgery.ConclusionThe current study reports a 3.3% patella loosening rate during this mid-term follow-up. Size 38 mm and larger patella components showed a significantly higher revision rate than smaller buttons and the authors advise caution when using large diameter patella components.

Comparison of a minimally invasive osteosynthesis technique with conventional open surgery for transverse patellar fractures

PurposeThe study aims to compare the efficacy and safety of a new minimally invasive osteosynthesis technique with those of conventional open surgery for transverse patellar fractures. MethodsIt was a retrospective study. Adult patients with closed transverse patellar fracture were included, and with open comminuted patellar fracture were excluded. These patients were divided into minimally invasive osteosynthesis technique (MIOT) group and open reduction and internal fixation (ORIF) group. Surgical time, frequency of intraoperative fluoroscopy, visual analogue scale score, flexion, extension, Lysholm knee score, infection, malreduction, implant migration and implant irritation in two groups were recorded and compared. Statistical analysis was performed by the SPSS software package (version 19). A p < 0.05 indicated statistical significance. ResultsA total of 55 patients with transverse patellar fractures enrolled in this study, the minimally invasive technique was performed in 27 cases, and open reduction was performed in 28 cases. The surgical time in the ORIF group was shorter than that in the MIOT group (p = 0.033). The visual analogue scale scores in the MIOT group were significantly lower than those in the ORIF group only in the first month after surgery (p = 0.015). Flexion was restored faster in the MIOT group than that in the ORIF group at one month (p = 0.001) and three months (p = 0.015). Extension was recovered faster in the MIOT group than that in the ORIF group at one month (p = 0.031) and three months (p = 0.023). The recorded Lysholm knee scores in the MIOT group were always greater than those in the ORIF group. Complications, such as infection, malreduction, implant migration, and implant irritation, occurred more frequently in the ORIF group. ConclusionCompared with the ORIF group, the MIOT group reduced postoperative pain and had less complications and better exercise rehabilitation. Although it requires a long operation time, MIOT may be a wise choice for transverse patellar fractures.

Patella non-resurfacing in primary total knee arthroplasty provides good functional results-a retrospective review of nine thousand three hundred forty six knees.

Patellar resurfacing has long been a contentious subject in TKA with no consensus and the literature yielding disparate results. The aim of this study was to evaluate the long-term functional outcomes and complications of patients undergoing primary TKA without patellar resurfacing (non-resurfacing). This study retrospectively analysed 9346 patients who underwent primary manual jig-based TKA without patellar resurfacing at a single high-volume arthroplasty centre between 2010 and 2018. Patients with a minimum threeyear follow-up irrespective of disease etiology and implant manufacturer were included in the study. Primary outcome was measured using Oxford knee score and patellofemoral Feller score. Secondary outcomes included determining the incidence of patellofemoral complications and re-operation rates following TKA. A total of 8695 knees were eligible for final evaluation having a mean follow-up of 6.6 years. Mean age of the patients was 62.6 (SD-7.5) years with female predominance of (N-6619, 70.8%). The majority of the patients had primary OA (N-8792, 94.1%) with varus deformity (N-8642, 92.46%). Depuy was the most used manufacturer (n = 2592, 26.4%) with the posterior stabilised (N-4127, 44.2%) design being the most predominant. The mean Feller score of the study population was 24.5 (SD = 3) with a majority of patients having good to excellent outcomes (86.95%, N-8424) and mean Oxford knee score was 36.9 (SD-6.9) with a majority of the patients having an OKS greater than 30 (87.1%, N-8133) with anterior knee pain (AKP) reported in only 4.8% patients (N-418). Most common complications included patellar clunk (N-56, 0.7%), traumatic patellar fractures (N-62, 0.8%), quadriceps tendon tear (N-54, 0.7%) and patellar dislocation (N-4, 0.05%) CONCLUSION: Patellar non-resurfacing has no detrimental impact on functional outcomes and incidence of AKP. We conclude that it is a safe, cost-effective and satisfactory approach in primary TKA with no significant complications.

Patellar Sleeve Fracture: An Important Consideration for Pediatric Knee Pain.

Patellar Sleeve Fracture: An Important Consideration for Pediatric Knee Pain.

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

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

Medial Patellofemoral Ligament Reconstruction Using Allografts in Skeletally Immature Patients

Background: Patellar instability has the highest incidence in adolescents aged between 14 and 18 years. The unique relationship between the medial patellofemoral ligament (MPFL) and the distal femoral physis in skeletally immature patients warrants precisely positioned MPFL graft insertion. A paucity of data are available evaluating the results of MPFL reconstruction using allograft tendon before skeletal maturity. Purposes: (1) To assess the results of MPFL reconstruction using allograft tendon in skeletally immature patients by analyzing redislocation and reoperation rates, radiological outcomes, and patient-reported outcomes and (2) to determine whether epidemiological, intraoperative, or radiographic factors influence recurrent instability and clinical outcomes. Study Design: Case series; Level of evidence, 4. Methods: Prospectively collected data were retrospectively analyzed for 69 skeletally immature patients who experienced a first-time or recurrent lateral patellar dislocation and were treated with anatomic MPFL reconstruction. Inclusion criteria were MPFL reconstruction using allograft and the availability of preoperative magnetic resonance imaging scans in the presence of open or partially open physes. Patients with <2 years of follow-up and patients with previous surgeries on the same knee were excluded from the study. Preoperative radiographic imaging was reviewed and analyzed. Trochlear dysplasia, tibial tubercle–trochlear groove distance, and patellar height were evaluated. Descriptive data, concomitant injuries, surgical procedure details, complications, and postoperative history were assessed via review of medical records and patient charts. Validated patient-reported and surgeon-measured outcomes were collected pre- and postoperatively, including Kujala score, Lysholm score, and Tegner activity score. Return-to-sports rate was assessed. The influence of epidemiological, intraoperative, and radiographic parameters on the redislocation rates and clinical outcomes was assessed using a multiple linear regression model. Results: A total of 79 physeal-sparing MPFL reconstructions (69 patients) met the inclusion criteria. The mean age of the patient cohort was 14.7 ± 1.8 years (range, 8.5-16.9 years). Within the mean follow-up time of 37.9 ± 12.1 months (range, 24-85 months after surgery, there were 12 patients with clinical failures resulting in reoperation. Eleven patients experienced a redislocation of the patella, and 1 patient sustained a transverse noncontact patellar fracture 6 months after index surgery that required operative fixation. No injuries to the distal femoral physes were clinically observed. At the final follow-up, patients had a mean Lysholm score (1-100) of 96.5 ± 6.7, a mean Kujala score (1-100) of 96.5 ± 7.4, and a mean Tegner Activity Scale score (1-10) of 4.9 ± 1.3. Patellar height and trochlear dysplasia did not influence redislocation or clinical scores. In total, 57 of the 63 patients (90.5%) who were engaged in sports before injury returned to the same or higher level of competition. In a subgroup analysis of patients who underwent isolated MPFL reconstruction (n = 44) without concomitant procedures, 9 patients (20.5%) experienced failure and had a redislocation. A univariate analysis of hazards for failure based on patient-specific variables was carried out. A body mass index ≥30 conveyed a hazard ratio of 2.51 (95% CI, 0.63-10.1; P = .19), and the tibial tubercle-trochlear groove distance by increments of 1 mm was associated with a hazard ratio of 2.02 (95% CI, 0.51-8.11; P = .32). Conclusion: Physeal-sparing anatomic reconstruction of the MPFL using an allograft tendon in skeletally immature patients was a safe and effective treatment for patellar instability, regardless of patellar height and trochlear dysplasia. Failure rates decreased when the MPFL reconstruction was performed concomitantly with a tibial tubercle osteotomy.