Distinct risk profiles for short-term surgical complications and venous thromboembolism exist among extensor mechanism repair procedures.

PURPOSE: Extensor mechanism injuries, which comprise patella fractures, patella tendon tears and quadriceps tendon tears, are severely debilitating injuries and a common cause of traumatic knee pathology that requires surgical intervention. Risk factors for short-term surgical complications and venous thromboembolism (VTE) in this population have not been well characterised. The aim of this study was to identify perioperative risk factors associated with these short-term complications. METHODS: The National Surgical Quality Improvement Program database was used to identify patients who underwent an isolated, primary extensor mechanism repair from 2015 to 2020. Patients were stratified by injury type. Demographic data were collected and compared. A multivariate logistic regression was used to control for demographic and comorbid factors while assessing risk factors for developing short-term complications. RESULTS: A total of 8355 patients were identified for inclusion in this study. Overall, 3% of patients sustained short-term surgical complications and 1% were diagnosed with VTE within 30 days of surgery. Patella fracture fixation had a nearly twofold higher risk for surgical complications compared to quadriceps tendon repair (p = 0.004). Patella tendon repair had a twofold higher risk for VTE (p = 0.045), specifically deep vein thrombosis (p = 0.020), compared to patella fracture fixation. Increasing age, smoking and American Society of Anesthesiologists Classifications 3 and 4 were also found to be risk factors for surgical complications (p = 0.012, p = 0.004, p = 0.011 and p = 0.032, respectively). CONCLUSION: This study used a nationally representative, widely validated, peer-reviewed database to provide valuable insights into risk factors for short-term postoperative complications associated with extensor mechanism repair procedures, revealing notable differences in risk profiles among distinct surgical procedures. The results of this study will inform surgeons and patients in enhancing risk assessment, guiding procedure-specific decision-making, optimising preoperative care, improving postoperative monitoring and contributing to future research of extensor mechanism injuries. LEVEL OF EVIDENCE: Level III.

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.

Cannulated compression screws with cable technique leads to a dramatic reduction in patella fracture fixation complications compared to tension band wiring.

INTRODUCTION: The aim of this study was to compare the clinical, radiological and functional outcomes between cannulated compression screw with cable construct (CS) and tension band wiring (TBW) in transverse patella fractures. MATERIALS AND METHODS: A retrospective study was conducted on patients surgically treated for AO/OTA 34C1 or 34C2 transverse patella fractures with CS or TBW technique between January 2019 and January 2023. Clinical outcomes included complications related to the implant, wound and fracture at 6 months and 1 year, time to achieving full weight bearing status and early perioperative clinical outcomes. Radiological outcomes included the time to fracture heals and delayed union. Functional outcome measures using the Oxford Knee Scale, 36-short form questionnaire and the Bartlett Anterior Knee Score were assessed. RESULTS: 73 patients were treated with CS (n = 33) or TBW (n = 40). TBW had higher complication rates: 25.0% (n = 10) required implant removal, 12.5% (n = 5) had wire breakage, 12.5% (n = 5) experienced fracture displacement while 52.5% (n = 21) experienced implant migration. In contrast, no CS patients had implant removals, wire breakage or fracture displacement and 3.0% (n = 1) experienced implant migration. At 1 day post-operatively, 87.9% (n = 29) CS group patients were able to ambulate as compared to the 55.0% (n = 22) of TBW patients. Furthermore, CS patients ambulated further distances at 11.8 ± 10.6 m than the TBW group (6.4 ± 7.4 m). The CS group (25.9 ± 24.6 days) also achieved full weight bearing status faster than the TBW group (43.6 ± 39.4 days). The time taken for the fracture to heal and functional outcomes were comparable among the two groups. CONCLUSIONS: The CS technique demonstrated lower complications, in particular, no CS patient had implant removals, wire migration or fracture displacement. Additionally, CS technique showed a faster return to ambulation and time to achieving full weight bearing status.

Can multiple miniplates improve the treatment of comminuted patellar fracture?

BACKGROUND: We have applied primarily multiple locking compression miniplates in treating multifragmentary, comminuted patellar fracture in combination with conventional fixation methods. METHODS: Medical and radiologic data were retrospectively reviewed for the patients surgically fixated with locking compression miniplates in patellar fracture of AO/OTA 34-C3. The primary outcome was bone union at the final follow-up, and the secondary outcomes were functional outcomes and postoperative complications associated with the procedure. For the functional assessment, the Lysholm score, Tegner scores, and the knee range of motion was compared. RESULTS: A total of twenty patients with AO/OTA 34-C3 patellar fracture were included in the study with an average follow-up period of 15 months (range:11 ~ 18 months) between June 2018 and November 2021. Eleven male and nine female patients presented an average age of 57.15 years. The primary fracture union was seen in all twenty patients, and the average time to the union was 15.6 weeks on serial radiograph follow-up. All patients did not show any postoperative complications, such as fixation failure, infection, or revision operations. Postoperatively, all patients achieved an average range of motion of 130 degrees, and the Lysholm and Tegners scores showed an average of 90.4 and 5.0 at the final follow-up, retrospectively. CONCLUSION: Fixations with miniplates in comminuted patellar fractures can be a useful option for effective osteosynthesis due to their versatile, efficient, and low-profile nature.

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.

Management of comminuted patellar fractures using suture reduction technique combined with the modified Kirschner-wire tension band.

OBJECTIVES: Surgical management of comminuted patella fractures remains a major challenge for the surgeon. We developed a suture reduction (SR) technique to better preserve the comminuted patella. The study aimed to compare the suture reduction technique with conventional reduction (CR) technique in the management of comminuted patellar fractures using the modified Kirschner-wire (K-wire) tension band. METHODS: From May 2016 to September 2020, a total of 75 patients with comminuted patellar fracture were reviewed retrospectively. Among these cases, 35 patients were in the suture reduction group with a mean age of 52 years, while 40 patients were in the conventional reduction group with a mean age of 53 years. All cases were closed fractures. Comminuted patellar fractures were classified as type 34-C3 according to the AO/OTA classification. Radiographs of the knee were obtained at routine follow-up to evaluate the reduction quality and fracture union. Clinical outcomes including range of motion (ROM), visual analog scale (VAS), Lysholm, and Böstman grading scales were measured at the last follow-up. Postoperative complications were also recorded. RESULTS: The average time from injury to surgery was 5.4 days in suture reduction group and 3.7 days in conventional reduction group (p < 0.05). The surgical time of suture reduction group was less than that of conventional reduction group, but there was no significant difference (p = 0.110) regarding surgical time between the two groups. The average blood loss in suture reduction group was 42.9 ml, while the average blood loss in conventional reduction group was 69.3 ml (p < 0.001). There was no difference regarding fracture union, ROM and knee function score (Lysholm score and Böstman scale) between the two groups. The complication rates were 17.1% in suture reduction group and 12.5% in conventional reduction group respectively (p > 0.05). CONCLUSIONS: In the treatment of comminuted patellar fractures with modified K-wire tension band, the use of suture reduction technique can shorten the surgical time, reduce the surgical trauma, and obtain satisfactory results. This new surgical technique may be particularly effective in management of comminuted patellar fractures when patellectomy would otherwise be considered.

3D reduction combined with the modified Kirschner-wire tension band for the treatment of comminuted patella fracture.

PURPOSE: A novel 3D reduction method combined with a modified Kirschner-wire tension band (3D MKTB) fixation method to treat comminuted patella fractures was introduced in this study. This study aims to evaluate the effectiveness and practicality of this novel technology. METHODS: This study is a retrospective case series study. Twenty-eight patients with closed comminuted patella fractures were treated with the novel 3D MKTB fixation method. Radiographs of the knee were obtained at the routine follow-up to assess fracture healing and widening of the articular step-off. Clinical outcomes including the degree of pain on a visual analogue scale (VAS), range of motion, Lysholm, and Bostman grading scales were measured at the last follow-up. The mean follow-up was 39.8 ± 10.5 (range 26-62) months. RESULTS: All patients had bony union at a mean of 11.4 ± 1.4 (range 9-14 weeks) weeks based on X-ray. No patient had evidence of internal fixation failure. Only two patients suffered from surgical complication. One patient suffered from postoperative superficial infection, and one patient suffered from internal fixation irritation. Articular step-off larger than 2 mm was not seen in any cases. The average VAS-related pain score was 0.5 ± 0.5 (range 0-1) points. The average range of motion was 0-138.6° ± 11.9° (range 90°-155°), all patients had full knee extension. The mean Lysholm and Bostman scores were 92.9 ± 3.5 (range 86-100 points) points and 28.5 ± 1.3 (range 24-30 points) points, respectively. CONCLUSION: The novel 3D reduction technique combined with the modified Kirschner-wire tension band technique is an effective, safe, and simple treatment option for comminuted patella fractures. LEVEL OF EVIDENCE: IV.

Biomechanical comparison of a novel tensioned cable construct versus tension band wiring for transverse patella fracture fixation.

PURPOSE: Tension band wiring (TBW) is the most widely accepted method for patella fracture fixation. The purpose of our study was to compare the biomechanical efficacy of a novel cable construct to TBW for the fixation of transverse patella fractures. The tensioned cable construct was hypothesized to have less fracture gapping after cyclic flexion-extension loading and greater ultimate load to failure as compared to TBW. METHODS: Transverse patellar osteotomies (AO/OTA 34C1.1) were performed on nine pairs of fresh-frozen human cadaveric whole legs (mean age 82.2 years, range 71-101). Treatment with TBW or tensioned cable construct was randomized within each specimen pair. Fracture site displacement was measured after 5000 flexion-extension cycles from 0° to 90° at 0.5 Hz. In load to failure testing, the knee was fixed at 45° of flexion and the quadriceps tendon was pulled proximally at 0.5 mm/sec until patella fixation failure. Comparisons were made using paired t-tests with alpha values of 0.05. RESULTS: Eight paired specimens completed the cyclic loading. The tensioned cable construct had significantly less fracture gapping than TBW (2.9 vs 10.9 mm; p = 0.020). Seven paired limbs underwent load to failure testing, which revealed no significant difference between the tensioned cable construct and TBW (1551.6 N vs 1664.0 N; p = 0.26). CONCLUSION: In this study of transverse patella fracture fixation, a tensioned cable construct demonstrated significantly less fracture gapping compared to TBW in response to cyclic loading with no significant difference in load at failure.

The radiographic soft tissue thickness is associated with wound complications after open reduction and internal fixation of patella fractures.

BACKGROUND: Displaced patella fracture is commonly treated with open reduction and internal fixation (ORIF). Wound complications after surgery often lead to prolonged hospitalization and dissatisfaction of patients. Periarticular adiposity and swelling may be associated with wound complications. The purpose of this study is to determine the relationship between periarticular soft tissue thickness and wound complications after ORIF of patella fractures. METHODS: We retrospectively studied 237 patients undergoing ORIF for patella fractures from June 2017 to February 2021 at our institution. We established periarticular soft tissue thickness ratio (PSTTR) to evaluate soft tissue status on lateral knee X-ray radiographs. Univariate analysis was performed to identify the association between PSTTR and postoperative wound complication. A receiver-operating characteristic (ROC) curve analysis was performed to evaluate the predictive value of PSTTR. RESULTS: The incidence of postoperative wound complication was 10.5%. Minor wound complication occurred in 24 patients, and major wound complication occurred in one patient. The average femoral PSTTR (fPSTTR) was 0.94 ± 0.17 and the average tibial PSTTR (tPSTTR) was 0.66 ± 0.16. fPSTTR proved to be associated with postoperative wound complication. In the ROC analysis of fPSTTR predicting postoperative wound complication, the area under curve (AUC) was 0.676, which indicated a moderate predictive value. CONCLUSIONS: PSTTR was a feasible method to assess periarticular soft tissue. The increased fPSTTR was associated with wound complications after ORIF of patella fractures.

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.

Combined internal fixation and transarticular external skeletal fixation to treat traumatic patellar fractures in five dogs.

CASE HISTORY: Medical records of dogs (n = 5) that had been treated for patellar fracture with transarticular external skeletal fixation (TA-ESF) to augment internal fixation, at a single referral hospital in the United Kingdom between 2015 and 2017, were reviewed. CLINICAL FINDINGS AND TREATMENT: At presentation, two dogs had polar patellar fractures, two had comminuted fractures and one dog had a transverse fracture. The median age at the time of the surgery was 21 (min 8, max 132) months and the median body weight was 19.0 (min 8.3, max 28.6) kg. In all cases, TA-ESF (Type IA lateral triangulated or modified Type II) was used in combination with internal fixation with pins and/or orthopaedic wire, supported by nylon leader line (patella-to-tibia mattress suture) and/or absorbable suture in a locking loop and/or circum-patellar pattern. All cases had short-term (6-12 weeks) post-operative radiographic follow-up, which showed evidence of fracture healing in 2/5 cases. All TA-ESF were removed 6 or 7 weeks post-operatively and four dogs had minor complications related to TA-ESF. More than 2 years post-operatively, the owners of all dogs were contacted and questioned using the Liverpool Osteoarthritis in Dogs questionnaire regarding the mobility of their pet. Four of the five cases were re-examined to evaluate their long-term outcomes. Based on the results of goniometric measurement of stifle range of motion, subjective gait assessment and objective gait analysis with a pressure-sensitive walkway, all dogs showed a satisfactory outcome at the final follow-up. CLINICAL RELEVANCE: A combination of internal fixation and TA-ESF for stabilisation of traumatic patellar fractures is a valid treatment option. Further investigations with larger case numbers are necessary to evaluate success and complication rates.

Prevalence and risk factors of surgical site infection after closed isolated patella fracture surgery: A prospective cohort study.

PURPOSE: Surgical site infection (SSI) after patella fracture surgery could be devastating and challenging. There is no large sample size study to investigate the prevalence and risk factors of it. The purpose of this study was to address this clinical issue. METHODS: A total of 820 patients who underwent patella fracture surgery between October 2014 and December 2018, were included. Demographic data, fracture type, injury mechanism, pre-operative stay, surgery-related variables, and pre-operative laboratory indexes were obtained from a prospective database. The optimum cutoff value of surgery duration was detected by receiver operating characteristic analysis. Univariate analysis and multivariate analysis were performed to determine the risk factors. RESULTS: A total of 17 patients developed SSI after patella fracture surgery, indicating a prevalence of 2.1%, with 11 cases (1.3%) for superficial infection and six cases (0.8%) for deep infection. After adjustment of multiple variables, current smoking, (OR, 18.6, CI, 3.5-99.0); albumin < 35 g/L, (OR, 7.4, CI, 1.1-52.3); diabetes mellitus, (OR, 8.8, CI, 1.3-59.4) and surgery duration > 79.5 minutes, (OR, 13.2, CI, 1.5-117.3) were identified to be independent risk factors of SSI after patella fracture surgery (p < 0.05). CONCLUSION: The prevalence of SSI in patients with closed isolated patella fracture was 2.1%, with 1.3% for superficial and 0.8% for deep infection. We recommend individualized risk stratification and targeted interventions for patients with risk factors (current smoking, albumin < 35 g/L, diabetes mellitus, and surgery duration > 79.5 minutes).

Patella Fracture Identified Using Point-of-care Ultrasound.

A 49-year-old female fell from standing. Her right knee extended into the air. She had acute right knee pain preventing weight-bearing. Her knee was most comfortable fully-extended. She could not flex it due to pain, nor extend it against resistance. Tenderness and a horizontal defect were noted over the anterior knee. Bedside ultrasound demonstrated a horizontally-fractured patella (confirmed on X-ray) with intact femoral and patellar tendons. She was put in a knee immobilizer and underwent surgery, with return to full function and activities. Ultrasound can identify patella fractures and help with early evaluation, management, and specialty referral, as well as ordering more-focused imaging. In one study, POCUS (point-of-care ultrasound) for patella fracture had 95% sensitivity, 63% specificity, 86% positive predictive value, and 83% negative predictive value. The dynamic nature of ultrasound allows a ruptured patella (87% sensitivity) or quadriceps tendon (100% sensitivity) to be excluded with high certainty.

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.

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.

Socioeconomic factors and individual lifestyles influencing the incidence of patella fractures: a national population-based survey in China.

BACKGROUND: We aimed to do a national survey on the population-based incidence of patella fractures and related risk factors fracture in China. METHODS: All the data on patella fractures were available from the China National Fracture Survey (CNFS) between January and May in 2015. And in the CNFS, all eligible household members were selected from 24 urban cities and 24 rural counties of eight provinces of China, with stratified random sampling and the probability proportional to size method used. Questionnaire was sent to every participant for data collection and quality control was accomplished by our research team members. RESULTS: A total of 512,187 valid questionnaires were collected, and relevant data were abstracted. There were a total of 69 patients with 69 patella fractures that occurred in 2014, indicating that the incidence was 13.5 (95% CI, 10.3-16.7))/100,000 person-years. Slip, trip, or fall from standing height was the most common cause, leading to 69.6% (48/69) of patella factures, followed by traffic accidents (18.8%, 13/69). Home and road were the first two most common places, where 86.9% of the overall injuries occurred. Age of 45-64 and 65-74 years, alcohol consumption and previous history of fractures were identified as independent risk factors for patella fracture. CONCLUSIONS: Specific public health policies focusing on decreasing alcohol consumption should be implemented. Individuals aged 45-64 and 65-74 should pay more attention to bone mass density and prevention of falls, especially those with previous history of fracture.

Treatment of displaced transverse fractures of the patella: modified tension band wiring technique with or without augmented circumferential cerclage wire fixation.

BACKGROUND: Displaced transverse fractures of the body of the patella are usually associated with disruption of extensor mechanism and should be fixed surgically. The most common method is a tension band wiring (TBW) technique. Some surgeons concurrently employ an augmented circumferential cerclage wiring (ACCW) technique to help fracture stabilization and aid in fracture healing; however, its role and effect on the treatment outcomes is unclear. METHODS: We performed a STROBE-compliant retrospective observational cohort study on all cases of acute closed patella fracture that were treated at our institution between 2006 and 2012. Of 185 episodes, 72 (38.9%) were eligible for this study according to our inclusion/exclusion criteria. We classified these subjects with AO/OTA type 34-C1.1 or 34-C2 lesions into two groups for analyses: fractures treated with modified TBW and ACCW (group 1, n = 27) and those treated with modified TBW alone (group 2, n = 45). Plain radiographs were used to evaluate radiographic outcomes and the effect of potential risk factors on fixation failure was analyzed by subgroup comparisons. RESULTS: Our results revealed that there were no significant differences in the rates of fixation failure (P = 0.620), nonunion (P = 0.620), and revision surgery (P = 0.620) between the groups. Although not statistically significant, there was a trend towards a positive risk association between fixation failure and age distribution > 60 years (10.0% vs. 0.0%, P = 0.124; OR = 8.0, P = 0.168) and > 70 years (9.4% vs. 2.5%, P = 0.321; OR = 4.0, P = 0.237) and the superficial level of the K-wires (12.0% vs. 1.5%, P = 0.117; OR = 6.3, P = 0.121). Regarding those modified TBW patients concurrently treated with an ACCW, the potential risk association between fixation failure and the superficial level of the K-wire was prone to increase further (28.6% vs. 0.0%, P = 0.060; OR = 18.6, P = 0.071). CONCLUSIONS: Concurrent application of an ACCW might be needless and not efficacious to help fracture stabilization and healing in patients having been treated with modified TBW for displaced transverse fractures of the body of the patella. Adherence to correct surgical technique such as putting the K-wires at the proper level and securing control of the both ends of the K-wires may be more important and help in improving outcomes.

Is There Any Role for Direct Repair of Extensor Mechanism Disruption Following Total Knee Arthroplasty?

BACKGROUND: Extensor mechanism disruption remains a challenging problem in total knee arthroplasty (TKA) with historically poor outcomes. The purpose of our study is to determine if patients undergoing acute extensor mechanism repair had different outcomes than patients undergoing allograft reconstruction. METHODS: We reviewed a series of 126 total knee arthroplasty patients requiring surgical repair or reconstruction of an extensor mechanism injury from 2005 to 2014 with a minimum of 24 months of follow-up. Demographics, comorbidities, Knee Society Scores, time from injury, and reoperations were all recorded from the medical record. A poor outcome was defined as an extensor lag >30°, postoperative Knee Society Scores <60, or a reoperation. A multivariate analysis was then performed to identify independent risk factors for a poor outcome. RESULTS: Of the 126 patients, there were 58 patients who underwent direct extensor repair (46%) and 68 patients who underwent allograft reconstruction (54%) at a mean postsurgical follow-up of 81.2 months. Rates of poor outcomes were comparably high in both groups (33% vs 44%, P = .192). Patella tendon repair had the highest rate of poor outcomes compared to quadriceps repair and patella fixation (63% vs 22% vs 8%, P = .002). Independent risk factors for poor outcomes included patients with a history of infection (odds ratio 4.559, P = .002) and injury greater than 2 weeks duration (odds ratio 4.237, P = .031). CONCLUSION: Outcomes following direct extensor mechanism are comparable to extensor mechanism allograft reconstruction; however, patients should be counseled regarding poor outcomes. Direct repair of patellar tendon injuries should likely be avoided due to prohibitively high complication rate.

Quantitative analysis of the patella following the harvest of a quadriceps tendon autograft with a bone block.

PURPOSE: The objective of this study was to determine parameters associated with patellar fracture after quadriceps tendon autograft harvest. METHODS: Thirteen non-fractured and five fractured patella surface models were created based on patient data obtained from a prospective randomized clinical trial in order to assess geometric parameters and bending stress. Measurements that describe the bone block harvest site geometry were used to calculate three normalized parameters. The relative depth parameter describes the thickness of the bone block harvest site with respect to the thickness of the patella at the harvest site. The asymmetry parameter defines the medial-lateral location of the bone bock harvest site. The normalized bending stress parameter assesses the bending stress experienced by the remaining bone beneath the bone block harvest site. RESULTS: The relative depth of the bone block harvest site in the non-fractured patellae was 27 ± 12 % and for the fractured patellae was 42 ± 14 % (p < 0.05). With a value <1 indicating a more lateral location of the harvest site, asymmetry for the non-fractured group was 1.0 ± 0.5 and 0.7 ± 0.4 for the fractured group (n.s.). The maximum bending stress experienced by the non-fractured patellae was (1.8 × 10(-3) ± 1.3 × 10(-3)) mm(-3) × M and for the fractured patellae was over three times greater (6.3 × 10(-3) ± 3.7 × 10(-3)) mm(-3) × M (p < 0.05). CONCLUSION: Based on the non-uniform geometry of the patella, an emphasis should be made on harvesting a standard percentage of patella thickness rather than a fixed depth. In order to minimize the incidence of a patellar fracture, bone blocks should not be taken laterally and should not exceed 30 % of the total patella thickness at the harvest site.