Cartilage degeneration is associated with activation of the PI3K/AKT signaling pathway in a growing rat experimental model of developmental trochlear dysplasia.

Introduction: Trochlear dysplasia is a commonly encountered lower extremity deformity in humans. However, the molecular mechanism of cartilage degeneration in trochlear dysplasia is unclear thus far. Objectives: The PI3K/AKT signaling pathway is known to be important for regulating the pathophysiology of cartilage degeneration. The aim of this study was to investigate the relationship of the PI3K/AKT signaling pathway with trochlear dysplasia cartilage degeneration. Methods: In total, 120 female Sprague-Dawley rats (4 weeks of age) were randomly separated into control and experimental groups. Distal femurs were isolated from the experimental group at 4, 8, and 12 weeks after surgery; they were isolated from the control group at the same time points. Micro-computed tomography and histological examination were performed to investigate trochlear anatomy and changes in trochlear cartilage. Subsequently, expression patterns of PI3K/AKT, TGFß1, and ADAMTS-4 in cartilage were investigated by immunohistochemistry and quantitative polymerase chain reaction. Results: In the experimental group, the trochlear dysplasia model was successfully established at 8 weeks after surgery. Moreover, cartilage degeneration was observed beginning at 8 weeks after surgery, with higher protein and mRNA expression levels of PI3K/AKT, TGFß1, and ADAMTS-4, relative to the control group. Conclusion: Patellar instability might lead to trochlear dysplasia in growing rats. Moreover, trochlear dysplasia may cause patellofemoral osteoarthritis; cartilage degeneration in trochlear dysplasia might be associated with activation of the PI3K/AKT signaling pathway. These results provide insights regarding the high incidence of osteoarthritis in patients with trochlear dysplasia. However, more research is needed to clarify the underlying mechanisms.

Patellofemoral Arthroplasty Improves Patellofemoral Alignment in Patients with Patellofemoral Osteoarthritis with Trochlear Dysplasia.

The impact of trochlear dysplasia on patellofemoral arthroplasty (PFA) has rarely been reported in the literature. The purpose of this study was to explore the effectiveness of PFA in patients with patellofemoral osteoarthritis (PFOA) associated with trochlear dysplasia. From January 2014 to March 2018, 35 patients with PFOA and trochlear dysplasia (29 females and 6 males), underwent PFA, were included in the present retrospective study. Radiological measurements including the patellar tilt (PT), congruence angle (CA), Blackburne-Peel ratio (BPR), tibial tuberosity-trochlear groove (TT-TG) distance, and lateral trochlear inclination (LTI) were assessed pre- and postoperatively to evaluate the changes in patellofemoral alignment. The patient-reported functional outcome was assessed using the Oxford Knee Score. The mean follow-up time was 24 months (range, 18-42 months). The intraclass correlation coefficients were excellent for all measurements. The patellofemoral alignment and knee function were significantly improved postoperatively. The PT decreased from 23.3 ± 6.3 degrees preoperatively to 6.4 ± 2.3 degrees postoperatively (p < 0.001). The CA decreased from 32.3 ± 8.6 degrees preoperatively to 10.2 ± 3.6 degrees postoperatively (p < 0.001). The lateral trochlear inclination increased from 8.3 ± 4.1 degrees preoperatively to 16.0 ± 1.2 degrees postoperatively (p < 0.001). The TT-TG distance decreased from 18.2 ± 3.8 mm preoperatively to 11.5 ± 3.3 mm postoperatively (p < 0.001). The BPR did not significantly change postoperatively (p = 0.390). The average Oxford Knee Score improved from 19.5 preoperatively to 29.2 at 6 months postoperatively (p < 0.001), 37.9 at 1 year postoperatively (p < 0.001), and 39.1 at final follow-up (p < 0.001). No patient developed patellofemoral malalignment or prosthesis loosening during short-term follow-up. PFA achieved favorable therapeutic results in patients with PFOA associated with trochlear dysplasia.

Early patellofemoral articular cartilage degeneration in a rat model of patellar instability is associated with activation of the NF-κB signaling pathway.

BACKGROUND: Patellar instability (PI) often increases the possibility of lateral patellar dislocation and early osteoarthritis. The molecular mechanism of early articular cartilage degeneration during patellofemoral osteoarthritis (PFOA) still requires further investigation. However, it is known that the NF-κB signaling pathway plays an important role in articular cartilage degeneration. The aim of this study was to investigate the relationship between the NF-κB signaling pathway and patellofemoral joint cartilage degeneration. METHODS: We established a rat model of PI-induced PFOA. Female 4-week-old Sprague-Dawley rats (n = 120) were randomly divided into two groups: the PI (n = 60) and control group (n = 60). The distal femurs of the PI and control group were isolated and compared 4, 8, and 12 weeks after surgery. The morphological structure of the trochlear cartilage and subchondral bone were evaluated by micro-computed tomography and histology. The expression of NF-κB, matrix metalloproteinase (MMP)-13, collagen X, and TNF-ɑ were evaluated by immunohistochemistry and quantitative polymerase chain reaction. RESULTS: In the PI group, subchondral bone loss and cartilage degeneration were found 4 weeks after surgery. Compared with the control group, the protein and mRNA expression of NF-κB and TNF-ɑ were significantly increased 4, 8, and 12 weeks after surgery in the PI group. In addition, the markers of cartilage degeneration MMP-13 and collagen X were more highly expressed in the PI group compared with the control group at different time points after surgery. CONCLUSIONS: This study has demonstrated that early patellofemoral joint cartilage degeneration can be caused by PI in growing rats, accompanied by significant subchondral bone loss and cartilage degeneration. In addition, the degeneration of articular cartilage may be associated with the activation of the NF-κB signaling pathway and can deteriorate with time as a result of PI.

Hindlimb torsional alignment changes in growing rabbits after patellar dislocation.

BACKGROUND: Torsional malalignment has been considered as a risk factor for patellar dislocation. But the influence of patellar dislocation for torsional alignment development remains unknown. The present study aims to investigate whether the torsional alteration of the hindlimb occurs after patellar dislocation in growing rabbits. METHODS: In the present study, 30 one-month-old rabbits were included. The experimental group consisted of 30 left knees of rabbits which underwent patellar lateral dislocation. The control group consisted of 30 right knees of the rabbits which no surgical procedure was performed. The Computed Tomography (CT) scan was performed after the surgery and at the point the rabbits were skeletal mature (5 months post-surgery). The angles of femoral version and tibial torsion were measured using a three-dimensional method and analyzed between the experimental group and the control group. RESULTS: After the surgery, the femoral version and tibial torsion in the experimental and control group were not significantly different. However, 5 months after surgery, the angle of femoral version in the experimental group (-5.50 ± 6.13°) was significantly different from that in the control group (-10.90 ± 4.74°) (P < 0.05). But the angle of tibial torsion in the experimental group (7.17 ± 7.25°) and control group (4.47 ± 6.34°) were not significantly different (P = 0.144). CONCLUSIONS: From this study, patellar dislocation can lead to alteration of femoral version in growing rabbits. So patellar dislocation may affect on lower extremity alignment. These findings may develop pathology and etiology of patellar dislocation.

Anatomical Medial Patellofemoral Ligament Reconstruction for Recurrent Patella Dislocation: Two-Strand Grafts versus Four-Strand Grafts.

The purpose of this study was to describe two anatomical medial patellofemoral ligament (MPFL) reconstruction methods: reconstruction with two-strand grafts and reconstruction with four-strand grafts and to evaluate the clinical and radiological results. From January 2010 to January 2013, patients who sustained recurrent patella dislocation and met inclusion criteria were included in the study and divided into two groups randomly to undergo MPFL reconstruction either by two-strand grafts (T group) or four-strand grafts (F group). Patients were followed up 1 month, 1 year, 2 years, and 3 years postoperatively. The apprehension test was applied to test patella stability. The Kujala score, Lysholm score, and Crosby-Insall grading were used to evaluate the function of the affected knee. The patellar congruence and patellar tilt angle were used to measure the morphology of the patellofemoral joint. In addition, patients' subjective assessments and complications were recorded. Thirty-eight patients in T group and 38 patients in F group were followed for at least 36 months. The apprehension test was positive in all patients preoperatively but was negative at follow-up. The Kujala score, Lysholm score, patellar congruence angle, and the patellar tilt angle of patients in both groups improved significantly at 36-month follow-up when compared with those assessed preoperatively. However, patients in the F group achieved better clinical results in terms of Kujala score, patellar congruence angle, patellar tilt angle, and Crosby-Insall grading when compared with those in the T group 3 years after the operation. Most patients (92% of patients in the T group and 97% of patients in the F group) were satisfied with the surgery. The anatomical MPFL reconstruction with two-strand grafts or four-strand grafts were both safe techniques for recurrent patella dislocation with satisfactory clinical outcomes. The anatomical fixation with four-strand grafts achieved better clinical and radiographic results in the follow-up, which may be a better reconstruction method.

The morphology of patella changed significantly after soft tissue correction for children with recurrent patella dislocation.

BACKGROUND: Although morphological improvement of femoral trochlea has been investigated in children with patellar dislocation after surgery, whether the patellar shape changed under the same condition is still unknown. The purpose of the study was to investigate the changes of patellar morphology in transverse plane following surgical correction of recurrent patellar dislocation in children. METHODS: A total of 22 patients with a mean age of 9.9 years (7 to 12) were included. All had unilateral recurrent patellar dislocation. The knees with recurrent patellar dislocation were treated with medial patellar retinaculum plasty and defined as the affected side. The contralateral knees with no symptom of patellar instability were considered as the unaffected side. All patients were treated between October 2014 and August 2018. Axial CT (Computed Tomography) scans were undertaken in all patients to assess the patella morphological characteristics on a particular axial image preoperatively and at the final follow-up. RESULTS: There were not significant differences about patellar transverse diameter, thickness and Wiberg angle between affected side and unaffected side before surgery and at the last follow-up respectively (The mean follow-up period: 28.0 ± 3.3 months). However, before surgery, the Wiberg-index in the affected side (0.74 ± 0.06) was significantly different from that in the unaffected side (0.64 ± 0.04). At the last follow-up, the Wiberg-index in the affected side (0.67 ± 0.05) and the unaffected side (0.65 ± 0.04) were not significantly different. Also, in the affected side, the Wiberg-index at the last follow-up was significantly lower than that before surgery (P < 0.05). The Wiberg-index in the unaffected side was not significantly different before surgery and at the last follow-up. CONCLUSION: The patellar morphology can change significantly after surgical procedures in children with patellar recurrent dislocation whose epiphysis is not closed.

Pigmented villonodular synovitis does not influence the outcomes following cruciate-retaining total knee arthroplasty: a case-control study with minimum 5-year follow-up.

BACKGROUND: Pigmented villonodular synovitis (PVNS) is a rare synovial disease with benign hyperplasia, which has been successfully treated with total knee arthroplasty (TKA). The purpose of this study was to investigate the middle-term follow-up outcomes of cruciate-retaining (CR) TKA in patients with PVNS. METHODS: From January 2012 to December 2014, a retrospective study was conducted in 17 patients with PVNS who underwent CR TKA as PVNS group. During this period, we also selected 68 patients with osteoarthritis who underwent CR TKA (control group) for comparison. The two groups matched in a 1:4 ratio based on age, sex, body mass index, and follow-up time. The range of motion, Knee Society Score, revision rate, disease recurrence, wound complications, and the survivorship curve of Kaplan-Meier implant were assessed between the two groups. RESULTS: All patients were followed up at least 5 years. There was no difference in range of motion and Knee Society Score between the two groups before surgery and at last follow-up after surgery (p > 0.05). In the PVNS group, no patients with the recurrence of PVNS were found at the last follow-up, one patient underwent revision surgery due to periprosthetic fracture, and three patients had stiffness one year after surgery (17.6% vs 1.5%, p = 0.005; ROM 16-81°), but no revision was needed. At 7 years, the implant survivorship was 90.0% in the PVNS group and 96.6% in the control group (p = 0.54). CONCLUSIONS: This study demonstrated that the function of patients with PVNS who underwent CR TKA had been significantly improved, and the survival rate of implants in these patients was similar to the patients with OA. Consequently, the patients with PVNS who underwent CR TKA might be an achievable option. However, these patients should pay more attention to the occurrence of postoperative stiffness complications.

Mini-midvastus versus medial parapatellar approach in total knee arthroplasty: difference in patient-reported outcomes measured with the Forgotten Joint Score.

BACKGROUND: Low knee awareness after minimally invasive total knee arthroplasty (TKA) has become the ultimate target of a natural-feeling knee that meets patient expectations. The objective of this research was to compare the clinical outcomes of TKA via the mini-midvastus (MMV) approach or the medial parapatellar (MPP) approach, and to evaluate which approach can lead to a better quality of life after surgery. METHODS: From January 2015 to December 2016, a retrospective cohort study was conducted in 330 patients who underwent TKA via a mini-midvastus (MMV) approach. During this period, we also selected 330 patients who underwent TKA via a medial parapatellar (MPP) approach (MPP group) for comparison. Clinical results were assessed with the visual analog scale score for pain, range of motion, and the Knee Society Score. The Forgotten Joint Score was used to analyze the ability to forget the joint. RESULTS: There were significant differences with regard to visual analog scale score, range of motion, and the Knee Society Score until 6 months after surgery between the MMV and MPP groups (p < 0.05), but the differences were not significant at 12 months, 24 months, and 36 months after surgery. However, there were significant differences in the Forgotten Joint Score between the groups during the follow-up period (p < 0.05). CONCLUSION: When forgetting the artificial joint after TKA is the ultimate target, better quality of life can be acquired by performing TKA via the MMV approach. In addition, compared with the MPP approach, the MMV approach can offer less pain and a faster recovery.

A surgical reduction technique for posterior cruciate ligament avulsion fracture in total knee arthroplasty: a comparison study.

BACKGROUND: Posterior cruciate ligament (PCL) avulsion fracture of the tibia is an uncommon but serious complication during primary cruciate-retaining total knee arthroplasty (TKA). The first objective of this report was to conduct a retrospective cohort study to investigate the incidence and potential risk factors of PCL avulsion fracture in primary cruciate-retaining TKA. The second objective was to assess the functional outcomes of the knee after reduction of PCL avulsion fracture. METHODS: From January 2014 to January 2016, 56 patients who experienced PCL avulsion fracture of the tibia in primary cruciate-retaining TKA were included in the study group. Patients in this group underwent reduction of avulsion fracture. In this period, we selected 224 patients (control group) for comparison. Patients in this group also underwent the same TKA, but no PCL avulsion fracture occurred. The range of motion of the knee and Knee Society Scores were assessed. The Forgotten Joint Score was used to analyze the ability to forget the joint. Differences were considered statistically significant at p < 0.05. RESULTS: In our series, the incidence of PCL avulsion fracture was 4.6%. There were no significant differences (p > 0.05) with regard to the preoperative or postoperative range of motion of the knee, final 4-year mean clinical score in the study and control groups 92.4 ± 2.7 and 93.6 ± 1.9, respectively, and mean functional scores of 85.1 ± 1.8 and 87.1 ± 1.2, respectively. CONCLUSIONS: The incidence of PCL avulsion fracture of the tibia is relatively high. Older age and female gender were the two risk factors of fracture in primary cruciate-retaining TKA. Reduction of PCL avulsion fracture with a high-strength line can achieve good stability and function of the knee.

Distal femoral morphological dysplasia is correlated with increased femoral torsion in patients with trochlear dysplasia and patellar instability.

AIMS: The purpose of this study was to explore the correlation between femoral torsion and morphology of the distal femoral condyle in patients with trochlear dysplasia and lateral patellar instability. METHODS: A total of 90 patients (64 female, 26 male; mean age 22.1 years (SD 7.2)) with lateral patellar dislocation and trochlear dysplasia who were awaiting surgical treatment between January 2015 and June 2019 were retrospectively analyzed. All patients underwent CT scans of the lower limb to assess the femoral torsion and morphology of the distal femur. The femoral torsion at various levels was assessed using the a) femoral anteversion angle (FAA), b) proximal and distal anteversion angle, c) angle of the proximal femoral axis-anatomical epicondylar axis (PFA-AEA), and d) angle of the AEA-posterior condylar line (AEA-PCL). Representative measurements of distal condylar length were taken and parameters using the ratios of the bianterior condyle, biposterior condyle, bicondyle, anterolateral condyle, and anteromedial condyle were calculated and correlated with reference to the AEA, using the Pearson Correlation coefficient. RESULTS: The femoral torsion had a strong correlation with distal condylar morphology. The FAA was significantly correlated with the ratio of the bianterior condyle (r = 0.355; p = 0.009), the AEA-PCL angle (r = 0.340; p = 0.001) and the ratio of the anterolateral condyle and lateral condyle (ALC-LC) (r = 0.309; p = 0.014). The PFA-AEA angle was also significantly correlated with the ratio of the bianterior condyle (r = 0.319; p = 0.008), the AEA-PCL angle (r = 0.231; p = 0.031), and the ratio of ALC-LC (r = 0.261; p = 0.034). In addition, the bianterior condyle ratio showed a significant correlation with the biposterior condyle ratio (r = -0.324; p = 0.027) and the AEA-PCL angle (r = 0.342; p = 0.021). CONCLUSION: Increased femoral torsion correlated with a prominent anterolateral condyle and a shorter posterolateral condyle compared with the medial condyle. The deformities of the anterior and posterior condyles are combined deformities rather than being isolated and individual deformities in patients with trochlear dysplasia and patella instability. Cite this article: Bone Joint J 2020;102-B(7):868-873.

Scalpel can achieve better clinical outcomes compared with electric cautery in primary total knee arthroplasty: a comparison study.

BACKGROUND: Whether using the scalpel can provide better and faster recovery after the primary total knee arthroplasty (TKA) is still controversial. The aim of this research was to compare the clinical outcomes of using the scalpel and the electric cautery in primary TKA. METHODS: From January 2016 to December 2017, a retrospective cohort study was conducted in 313 patients who underwent unilateral primary TKA by using the scalpel (group S). During this period, we selected 313 patients who underwent unilateral primary TKA by using the electric cautery (group E) for comparison. The tourniquet time, operative time, blood loss, wound complications, visual analog score for pain, range of motion, Knee Society Score were assessed between the two groups. The Forgotten Joint Score was used to analyze the ability to forget the joint. RESULTS: There were no significant differences in tourniquet time, operative time, blood loss between the two groups (p > 0.05). In the group S, the visual analog score for pain, range of motion, Knee Society Score were found better results at 1 week, 1 month, 3 months, 6 months, 12 months and 24 months after surgery (p < 0.05). Besides, during the follow-up period, the Forgotten Joint Score was significantly higher compared with group E (p < 0.05). CONCLUSION: In this research, the patients who underwent TKA by using the scalpel could achieve better clinical outcomes. In addition, if forgotten artificial joint after TKA was the final goal, the patients who underwent TKA by using the scalpel would acquire better quality of life.

Anterior-medial collateral ligament portal : easy access to the torn posteromedial horn of the medial meniscus.

The posteromedial horn of the medial meniscus is prone to injury, and repair of a tear in this portion of the medial meniscus is especially challenging for the arthroscopist. We present a novel technique that allows good management of the posterior horn of the medial meniscus, even in patients with tight medial compartments. This technique uses two standard portals (the anterolateral portal and the anteromedial portal) to conduct arthroscopic examination, and uses a third portal as the workhorse portal to manage the posterior region so that the posterior horn tear can be easily removed. This new third portal is named the anterior-medial collateral ligament portal, and is positioned anterior to the anterior rim of the medial collateral ligament. This three-portal technique decreases the difficulty associated with management of the posteromedial region in knees with tight medial compartments.

Intracoronary Nicorandil and the Prevention of the No-Reflow Phenomenon During Primary Percutaneous Coronary Intervention in Patients with Acute ST-Segment Elevation Myocardial Infarction.

BACKGROUND This study aimed to investigate intracoronary nicorandil treatment on the no-reflow phenomenon (NRP) during primary percutaneous coronary intervention (PCI) in patients with acute ST-segment elevation myocardial infarction (STEMI) and to compare nicorandil with sodium nitroprusside. MATERIAL AND METHODS Patients with sustained acute STEMI who underwent primary PCI (N=120) were randomly assigned to three groups: the nicorandil-treated group (N=40) had 2 mg of nicorandil injected into the coronary artery at 2 mm beyond the occlusion with balloon pre-dilation; the sodium nitroprusside-treated group (N=40) underwent the same procedure, but with 200 µg of sodium nitroprusside; the control group (N=40) received PCI and balloon pre-dilation only. Coronary angiography, incidence of NRP, hypotensive episodes, ST-segment resolution (STR) rate, levels of N-terminal pro-brain natriuretic peptide (NT-proBNP), creatine kinase-MB (CK-MB), cardiac troponin I (cTnI), wall motion score index (WMSI), and left ventricular ejection fraction (LVEF) were measured before and after primary PCI. Major adverse cardiovascular events (MACEs) post-PCI and at three-month follow-up were recorded. RESULTS Patients in the sodium nitroprusside and nicorandil groups had significantly improved thrombolysis in myocardial infarction (TIMI) scores, TIMI myocardial perfusion grade (TMPG), and ST-segment elevation resolution (STR) (P<0.05), and a significantly lower incidence of NRP (P=0.013). The incidence of intraoperative hypotension in the sodium nitroprusside group was significantly greater than the nicorandil and control groups (P=0.035). CONCLUSIONS Patients with sustained acute STEMI undergoing primary PCI, treated with intracoronary nicorandil had a reduced incidence of the NRP, improved myocardial perfusion and cardiac function.

Early patellar dislocation can lead to tibial tubercle lateralization in rabbits.

PURPOSE: To investigate the effects of early patellar dislocation on the tibial tubercle location. METHODS: Sixty knees from 30 healthy 1-month-old New Zealand white rabbits were randomly divided into two groups of 30 knees each. Group A (control group) comprised the left knees, which underwent no surgical procedures. Group B comprised the right knees, which underwent patellar dislocation surgery. Computed tomography (flexion 0°) was performed preoperatively and 6 months post-operatively. Measurements included the tibial tuberosity-trochlear groove distance (TT-TG) and tibial tubercle lateralization. RESULTS: No significant difference in the TT-TG or tibial tubercle lateralization was found between the two groups preoperatively. Six months post-operatively, however, the mean TT-TG in Group A (no patellar dislocation) and Group B (patellar dislocation) was 1.0 ± 0.4 and 3.0 ± 0.7 mm, respectively (p < 0.05). The mean tibial tubercle lateralization also showed a significant difference between Groups A and B at 6 months post-operatively (0.5 ± 0.1 and 0.6 ± 0.0, respectively; p < 0.05). CONCLUSIONS: Early patellar dislocation can lead to tibial tubercle lateralization and an increased TT-TG. Clinically, early intervention for adolescent patients with patellar dislocation will be important. LEVEL OF EVIDENCE: Prospective comparative study, Level II.

Double-bundle anatomical medial patellofemoral ligament reconstruction with lateral retinaculum plasty can lead to good outcomes in patients with patellar dislocation.

PURPOSE: To evaluate the clinical outcomes of double-bundle anatomical medial patellofemoral ligament (MPFL) reconstruction combined with lateral retinaculum plasty versus isolated MPFL reconstruction for patellar dislocation. METHODS: From 2011 to 2013, 64 patients underwent either double-bundle anatomical MPFL reconstruction combined with lateral retinaculum plasty (Group A, 32 patients), or isolated MPFL reconstruction (Group B, 32 patients). Clinical evaluations were performed 2 years post-operatively and included determination of the number of patients with patellar redislocation, the patellar tilt angle, lateral patellar shift, subjective symptoms, and functional outcomes as evaluated with the Kujala score and Lysholm score. RESULTS: No dislocation or subluxation occurred during the 25-month follow-up. Radiographically, the patellar tilt angle was 6.0° ± 1.7° in Group A and 6.7° ± 2.0° in Group B, without a significant difference (n. s). The lateral patellar shift was 8.0 ± 2.6 mm in Group A and 8.5 ± 2.4 mm in Group B (n. s). The mean Kujala score was 91.8 ± 3.7 in Group A and 91.5 ± 3.6 in Group B post-operatively (n. s), and the mean Lysholm score was 92.5 ± 3.8 and 90.8 ± 4.9, respectively (n. s). CONCLUSIONS: Double-bundle anatomical MPFL reconstruction with lateral retinaculum plasty is a promising procedure that provides a new option for patellar dislocation. LEVEL OF EVIDENCE: III.

Lateral retinaculum plasty instead of lateral retinacular release with concomitant medial patellofemoral ligament reconstruction can achieve better results for patellar dislocation.

PURPOSE: To elucidate the outcomes of lateral retinaculum plasty versus lateral retinacular release with concomitant medial patellofemoral ligament (MPFL) reconstruction. METHODS: In a prospective study, 59 patients treated at our institution from 2012 to 2014 were included. The 59 patients were randomly divided into two groups. Group I included 27 patients who underwent lateral retinacular release and MPFL reconstruction. Group II included 32 patients who underwent lateral retinaculum plasty and MPFL reconstruction. All patients were followed up for at least 2 years and all assessments were performed both pre- and post-operation. Clinical evaluation consisted of the Kujala score, patellar medial glide test, and patellar tilt angle, patellar lateral shift, and congruence angle, measured on CT scan. RESULTS: Significant improvement was seen after surgery in both groups. The group of lateral retinaculum plasty achieved better results than the group of lateral retinacular release. No statistically significant differences were found in lateral patellar shift (ns) or congruence angle (ns) between the groups. There were significant differences in Kujala score (P < 0.05) patellar tilt angle (P < 0.05), and patellar medial glide test (P < 0.05) between the groups. CONCLUSIONS: MPFL reconstruction with lateral retinaculum plasty yielded better results than MPFL with lateral retinacular release. Postoperatively, medial and lateral function were restored, and patellar tracking was normal. Lateral retinaculum plasty is a new method that reduces the complications of lateral retinacular release for patellar dislocation. LEVEL OF EVIDENCE: II.

Medial Patellofemoral Ligament Reconstruction with Semi-Patellar Tunnel Fixation: Surgical Technique and Mid-Term Follow-Up.

BACKGROUND The present study aimed to describe a new safe and economical technique for medial patellofemoral ligament (MPFL) reconstruction with satisfactory clinical outcomes, and present the results of a four-year follow-up. MATERIAL AND METHODS Thirty-two patients with recurrent patella dislocation, who underwent MPFL reconstruction with two semi-patellar tunnels and hardware-free patellar fixation between 2011 and 2013, were included in the study. Patella stability was tested by an apprehension test preoperatively and at follow-up. Knee function was evaluated using the Kujala score, Lysholm score, and Crosby-Insall grading system. Patellar congruence angle and patellar tilt angle were measured using an axial computed tomography scan. Furthermore, objective feelings of patients and complications were recorded. RESULTS Thirty knees (30 patients) were followed for a minimum of 48 months. The apprehension test was positive in all patients preoperatively, but negative at follow-up. Kujala and Lysholm scores increased from 58.9±9.6 to 92.0±4.8 (p<0.001) and 53.3±5.6 to 91.6±3.5 (p<0.001), respectively, at the last follow-up. Seventeen patients were graded as excellent and 13 were graded as good by the Crosby-Insall grading system. The patellar congruence angle and patellar tilt angle also improved significantly. No patient experienced patellar re-dislocation, subluxation, or patella fracture. Most patients (93%) were satisfied with the surgery. CONCLUSIONS MPFL reconstruction with two semi-patellar tunnels and hardware-free patellar fixation was described and the study observations indicated it was a safe and economical surgical procedure for recurrent patella dislocation with satisfactory results. It could be an alternative surgery method for patients with patella recurrent dislocation.

Patella morphological alteration after patella instability in growing rabbits.

BACKGROUND: The shape of the patella has been considered to be a predisposing factor resulting in patellar instability, but the effects of abnormal patella position during its development are unclear. The present study evaluated patellar morphological changes after patella instability and evaluated the influence of patellar instability on the patella shape. METHODS: Twenty rabbits that were 2 months old were included in the study. The left knee of each rabbit, defined as the experimental group (N = 20 knees/group), underwent a medial soft tissue restraint release. The right knee of each rabbit, defined as the control group (N = 20 knees/group), did not undergo any surgical procedures. A CT scan was performed on each knee before surgery and 6 months post-surgery to measure the transverse diameter, thickness, Wiberg index, and Wiberg angle for analysis of the patellar morphological changes. Cross-specimen examination was conducted to evaluate the differences between the experimental group and the control group. RESULTS: The four indices remained the same between the two groups before surgery. However, 6 months after surgery, the mean transverse diameter of the patellae in the experimental group was significantly longer than that in the control group (P < 0.001), while the mean thickness in the experimental group was not significantly greater than that in the control group (P = 0.314), resulting in a flattened shape. The Wiberg indices were not significantly different between the two groups. However, the mean Wiberg angle was higher in the experimental group than in the control group (P < 0.001), which resulted in a flattened articular surface of the patella. CONCLUSION: The sectional shape and articular surface of the patella became more flattened after patella instability in this study, which indicates that patella dysplasia could be caused by patella instability. Clinically, early intervention for adolescent patients with patella instability is important.

Cryptosporidium Contamination and Attributed Risks in Yunlong Lake in Xuzhou, China.

Swimming in surface water bodies (e.g., lakes, rivers) can expose the human body to substantial risk of infection by Cryptosporidium. These findings are from a one-year investigation on the occurrence and distribution of the protozoan parasite Cryptosporidium in Yunlong Lake, Xuzhou, China. Cryptosporidium oocysts were detected by immunofluorescence microscopy. From January to November of 2015, 180 samples (120 water samples and 60 sediment samples) were collected and analyzed. Among them, 42 (35%) water samples and 28 (47%) sediment samples tested positive for Cryptosporidium. The concentration of Cryptosporidium oocysts in the water samples was 0-8/10 L and 0-260/g in sediment samples. Results revealed that July was the highest risk period for both swimming and diving with an estimated probability of infection from swimming of greater than 18 per 10,000 swim sessions. It was concluded that swimming or diving in Yunlong Lake has a higher risk of Cryptosporidium infection than the acceptable risk level set by the United States Environmental Protection Agency. Thus, regular monitoring of water quality in recreation water bodies is strongly recommended.

Surgical versus Nonsurgical Treatments of Acute Primary Patellar Dislocation with Special Emphasis on the MPFL Injury Patterns.

The objective of the present study was to compare the clinical results of the surgical versus nonsurgical treatments of acute primary patellar dislocations with a medial patellofemoral ligament (MPFL) injury in the nonoverlap region with the vastus medialis oblique. In this study, 62 patients with an acute patellar dislocation and a concurrent MPFL injury in the nonoverlap region were randomly divided into two groups based on their birth years (even vs. odd years) and received either surgical or nonsurgical treatment. Of the 62 eligible patients, 30 were in the nonsurgical treatment group (Group 1) and 32 were in the surgical group (Group 2). Patellar stability tests and the Kujala knee questionnaire were performed, and radiographs were evaluated for patellar tilt and the lateral shift ratio by two blinded investigators. An osteochondral injury was noted in six (23.1%) patients from Group 1 and five (16.7%) patients from Group 2, with no statistical difference between the two groups. The mean Kujala score was 80.19 ± 5.07 and 93.57 ± 4.03 (p < 0.001) between the surgical and nonsurgical groups, respectively. The mean patellar tilt was 8.96 ± 1.64 and 6.83 ± 1.44 degrees (p < 0.001) and the lateral shift ratio was 11.08 ± 1.99 and 9.23 ± 1.96 (p = 0.001) between the surgical and nonsurgical groups, respectively. This study showed that the surgical treatment of MPFL injuries in the nonoverlap region achieved better clinical outcomes and improved subjective knee function compared with conservative therapy. Surgery should therefore be considered as the treatment of choice for these specific injuries.