[Comparison of acute sports injury between recreational skiers and skiers].

OBJECTIVE: To compare and analyze the difference between the injuries of recreational skiers in public ski resorts and those of skiing athletes in official competitions, and to explore the suggestions of medical insurance for these two types of skiers. METHODS: The injury data of recreational skiers in Chongli District, Zhangjiakou City, Hebei Province during 2018-2019 and 2019-2020 snow seasons, and the injury data of skiers in two official international skiing competitions during 2019-2020 snow season and domestic test events in Chongli District of 2021 Winter Olympic Games were analyzed retrospectively, and the similarities and differences were compared. RESULTS: A total of 1 187 injuries occurred to recreational skiers in the two public ski resorts during the 2018-2019 snow season, with an injury rate of 0.3%.There were 1 277 injury sites in total, and the most frequent injury sites were head and neck (230 cases, 18.0%), followed by knee joint (204 cases, 16.0%) and lower extremity (131 cases, 10.3%). Thirty-one skiers were injured in the two official international skiing competitions in the 2019-2020 and 2020-2021 snow season, and in the domestic test competitions in the 2021 Winter Olympic Games, and the injury rates were 11.5%, 17.2% and 12.0%, respectively. There were 37 injury sites in total, among which 11 (29.7%) were in the head and neck, followed by 6 (16.2%) in the knee joint and 5 (13.6%) in the chest, rib and abdomen. CONCLUSION: In order to better guarantee the safety of skiers and timely provide corresponding medical help, safety facilities and technical guidance should be added to the snow resort for leisure skiing, and medical stations should be set up in the snow resort. As the formal ski racing for skiing athletes during the game has 30 to 80 times higher injury ratesthan recreational skiers, and compared with the recreational skiing, head and neck injury rate is higher, and the damage is much heavier, more complete first aid facilities and experienced medical workers are, needed so the field should be equipped with the circuit inside the quantities, track fixed outside the clinic, surrounding referral hospitals set up trauma centers to provide athletes with more timely medical care.

[Management algorithm for septic arthritis after anterior cruciate ligament reconstruction].

OBJECTIVE: To summarize the experience in the diagnosis and management of septic arthritis after anterior cruciate ligament reconstruction. METHODS: A retrospective review was conducted of all the arthroscopic anterior cruciate ligament reconstructions performed at Department of Sports Medicine, Peking University Third Hospital between January 2001 and December 2020. In the study, 65 of 27 867 patients experienced postoperative septic arthritis. The incidence, presentation, laboratory results, treatment, and outcome of all the infected patients were analyzed. The experiences of diagnosis and management of septic arthritis after anterior cruciate ligament reconstruction were summarized. RESULTS: A total of 27 867 anterior cruciate ligament reconstructions were performed at our department between January 2001 and December 2020. In the study, 65 (0.23%) patients were identified with postoperative septic arthritis. The most common symptoms of the infected patients were fever (38.7±0.5) ℃, knee swelling, pain, and restricted motion. The mean peripheral white blood cell count (WBC) was (9.2±2.6)×109/L (range 4.2×109/L-19.4×109/L), with (72.5±6.3) % (range 54.9%-85.1%) polymorphonuclear neutrophils (N). The mean erythrocyte sedimentation rate (ESR) was (59.9±24.1) mm/h (range 9-108 mm/h), C-reactive protein (CRP) was (10.9±5.7) mg/dL (range 1.2-30.8 mg/dL), and fibrinogen (FIB) level was (7.0±1.6) g/L (range 3.7-10.8 g/L). All of the laboratory results were statistically higher in the infection group compared with the normal postoperative group (P＜0.001). The synovial white blood cell count (SWBC) of aspirated knee joint fluid was (45.0±29.8)×109/L (range 7.1×109-76.5×109/L). Polymorphonuclear cell percentage (PMNC) was (90.27±7.86) % (range 60%-97%). In the study, 45 patients (69.2%) had positive aspirate cultures. Microbiology showed coagulase-negative Staphylococcus (CNS) and Staphylococcus aureus (SA) were the most common bacterium (34 cases and 7 cases, individually). There were 26 methicillin-resistant Staphylococcus. Both conservative (16 patients) and operative (49 patients) treatments were effective, but conservative group had a longer recovery time (5.6 d vs. 1.6 d, P=0.042). CONCLUSION: Septic arthritis after arthroscopic anterior cruciate ligament reconstruction is a rare but potentially devastating complication. The correct diagnosis relies on synovial fluid analysis and bacterial culture. Our proposed treatment protocol is arthroscopic debridement and antibiotic therapy as quickly as possible.

[Mid-to-long term clinical outcomes and predictors after anterior cruciate ligament revision].

OBJECTIVE: To assess the mid-to-long term clinical outcomes after anterior cruciate ligament (ACL) revision surgery and to analyze their predictors. METHODS: The medical records of 235 patients undergoing ACL revision surgery between Jan. 2001 and Dec. 2015 at Department of Sports Medicine, Peking University Third Hospital were reviewed. Data were collected including demographic information, information related to revision surgery (time and cause of graft failure, date of revision surgery, surgical technique, combined injuries and management, etc.), as well as information related to primary ACL reconstruction (time, cause and mechanism of first-time ACL rupture, date of primary ACL reconstruction, surgical technique, combined injuries and management, etc.). Patients were followed up at least 2 years after revision surgery for clinical outcomes [Tegner score, Lysholm score, and International Knee Documentation Committee (IKDC) subjective knee score]. Post-revision surgeries on the involved knee and the contralateral knee joint were also documented. Multivariate regression model was used to analyze the predictors of clinical outcomes after ACL revision surgery. RESULTS: A total of 166 (70.63%) patients were followed up at a mean of (4.44±2.40) years (2.03-14.63 years). Clinical outcomes improved significantly at the last follow-up from pre-operative level, with the Lysholm, Tegner, and IKDC scores improving from 70.51±21.25, 3.39±1.77, 63.78±15.04 to 88.64±14.36, 4.67±1.739, 80.23±13.31 (P < 0.05), respectively. Three (1.81%) patients experienced infection while 39 (23.49%) patients underwent surgery after revision surgery during the follow-up. Compared with that those occurred during sports, graft failure that occurred during daily activities or due to surgical technical errors that led to poorer clinical outcomes, with the Lysholm, Tegner, and IKDC scores of 9.90 (95%CI: 1.49-18.31), 1.41 (95%CI: 0.10-2.72), 10.35 (95%CI: 0.17-20.54), and 8.53 (95%CI: 1.31-15.75), 1.28 (95%CI: 0.14-2.43), 9.39 (95%CI: 1.03-17.74) lower, respectively. Compared with antero-medial portal, transtibial technique for placement of the femoral bone tunnel showed poorer Lysholm scores of 11.18 (95%CI: 4.73-17.63, P=0.001). Concurrent repair of medial meniscus yielded higher IKDC scores of 11.06 (95%CI: 1.21-20.92, P=0.029) than those with intact medical meniscus. Other factors showed no significant effect. CONCLUSION: ACL revision surgery is able to restore knee stability and improve knee function. Graft failure caused by sports, concurrent repair of medical meniscus and antero-medial portal technique predicts better outcomes after revision surgery.

[Finite element analysis of the graft stresses after anterior cruciate ligament reconstruction].

OBJECTIVE: To explore the stress distribution characteristics of the graft after anterior cruciate ligament (ACL) reconstruction, so as to provide theoretical reference for the surgical plan of ACL reconstruction. METHODS: Based on 3D MRI and CT images, finite element models of the uninjured knee joint and knee joint after ACL reconstruction were established in this study. The uninjured knee model included femur, tibia, fibula, medial collateral ligament, lateral collateral ligament, ACL and posterior cruciate ligament. The ACL reconstruction knee model included femur, tibia, fibula, medial collateral ligament, lateral collateral ligament, ACL graft and posterior cruciate ligament. Linear elastic material properties were used for both the uninjured and ACL reconstruction models. The elastic modulus of bone tissue was set as 17 GPa and Poisson' s ratio was 0.36. The material properties of ligament tissue and graft were set as elastic modulus 390 MPa and Poisson's ratio 0.4. The femur was fixed as the boundary condition, and the tibia anterior tension of 134 N was applied as the loading condition. The stress states of the ACL of the intact joint and the ACL graft after reconstruction were solved and analyzed, including tension, pressure, shear force and von Mises stress. RESULTS: The maximum compressive stress (6.34 MPa), von Mises stress (5.9 MPa) and shear stress (1.83 MPa) of the reconstructed ACL graft were all at the anterior femoral end. It was consistent with the position of maximum compressive stress (8.77 MPa), von Mises stress (8.88 MPa) and shear stress (3.44 MPa) in the ACL of the intact knee joint. The maximum tensile stress of the graft also appeared at the femoral end, but at the posterior side, which was consistent with the position of the maximum tensile stress of ACL of the uninjured knee joint. More-over, the maximum tensile stress of the graft was only 0.88 MPa, which was less than 2.56 MPa of ACL of the uninjured knee joint. CONCLUSION: The maximum compressive stress, von Mises stress and shear stress of the ACL graft are located in the anterior femoral end, and the maximum tensile stress is located in the posterior femoral end, which is consistent with the position of the maximum tensile stress of the ACL of the uninjured knee joint. The anterior part of ACL and the graft bore higher stresses than the posterior part, which is consistent with the biomechanical characteristics of ACL.

[Changes of electroencephalography power spectrum during joint position perception test after anterior cruciate ligament rupture].

OBJECTIVE: To measure the electroencephalography (EEG) of the patients with anterior cruciate ligament (ACL) rupture when performing joint position perception movement task, to compare the differences between the ACL rupture side and the unaffected side, to identify the EEG change in the power spectrum caused by the ACL rupture, and to provide evidence for the diagnosis, treatment and rehabi-litation for ACL injury as well as knee instability. METHODS: Sixteen male patients, selected from the Department of Sports Medicine, Peking University Third Hospital from November 2014 to April 2015, with only ACL rupture on one side used isokinetic muscle strength testing equipment were enrolled in the study to perform unilateral active knee joint positional movement and passive knee joint positional movement tasks. EEG was recorded to compare between the affected and unaffected limb of ACL rupture patients when doing single leg movement tasks, including passive knee joint position test and active knee joint position sensation test. The target position of the active knee joint position movement task and the passive knee joint position movement task was 30 degrees of knee flexion. RESULTS: During the passive knee joint position test, there was no significant difference in EEG power spectrum of Delta[F (1, 15)=0.003, P=0.957, ηP2 =0.001], Theta[F (1, 15)=0.002, P=0.962, ηP2 < 0.001], Alpha[F (1, 15)=0.002, P=0.966, ηP2 =0.001], Beta[F (1, 15)=0.008, P=0.929, ηP2 =0.001] at Fz, Cz, and Pz between the affected and unaffected limbs in the ACL patients. During the active knee joint position movement task, the EEG power spectrum of Delta, Theta, Alpha, Beta at Fz and Cz location, on the affected side was significant higher than on the unaffected side. CONCLUSION: This study compared the differences between the ACL rupture side and the unaffected side during active knee position movement task and passive knee position movement task, and identifyied the EEG changes in the power spectrum caused by the ACL rupture, It was found that the central changes caused by unilateral ACL rupture still existed during contralateral (unaffected) side movement. The EEG power spectrum of the affected side during active exercise was significantly higher than that of the unaffected side This study provides new electrophysiological evidence for the study of ACL injury.

[Effects of visual restoration on dynamic plantar pressure features in elder individuals].

OBJECTIVE: To analyze the effects of visual restoration after cataract surgery on plantar pressure and biomechanics of foot in elder individuals. METHODS: Thirty-two patients [male/female 5/27, (70.1±5.2) years old] with age-related cataract were recruited between October 2016 and December 2019. The footscan system was employed to record the data of plantar pressure during level walking before and 1-month after the cataract surgery. Parameters of peak pressure (PP), impulse (I), pressure-time integral (PTI) and time to peak pressure (TPP) from the regions of the 1st toe (T1), 2nd to 5th toes (T2-5), 1st to 5th metatarsal heads (M1-M5), midfoot (MF), medial hindfoot (HM) and lateral hindfoot (HL) were analyzed respectively. RESULTS: Post-operatively, the visual function was effectively reconstructed with improved visual acuity in both eyes (Z=-4.878, -4.801; P < 0.001). The PP (t=2.266, P=0.031) and I (t=2.152, P=0.039) values in M2 region on the dominant side (right foot) increased statistically at post-operative phase, while the changes of pressure and temporal para-meters in other regions remained stable. There was laterality in plantar pressure at pre-operative phase, manifested as greater PP values in M1, M2, MF, and HM regions on the dominant sides (t=-2.414, -2.478, -2.144, -5.269; P < 0.05), greater PP values in T1, M3, M5 and HL regions on the non-dominant sides (t=4.830, 3.155, 2.686, 3.683; P < 0.05), greater I values in M1, MF, and HM regions on the dominant sides (t=-2.380, -2.185, -5.320; P < 0.05) and greater I values in T1, M3, M5 and HL regions on the non-dominant sides (t=4.489, 2.247, 2.838, 3.992; P < 0.05). post-operatively, the pressure tended to be compatible between the two sides in regions of M3 and MF, while the magnitude of laterality in regions of M1 (ZPP△= -2.721, P=0.007; ZI△=-2.581, P=0.010), M2 (ZPP△=-2.674, P=0.007; ZI△=-2.375, P=0.018) and M5 (ZPP△=1.991, P=0.046; ZI△=2.150, P=0.032) was further increased. CONCLUSION: Changes in plantar pressure after cataract surgery were characterized as increased pressure in the 2nd metatarsal head area on the dominant side. Visual restoration might intensify the laterality in the medial of forefoot on the dominant side and the lateral of forefoot on the non-dominant side.

[Two kinds of lateral retinacular release for lateral patellar compression syndrome:a retrospective comparative study].

Objective: To compare the clinical effects of arthroscopic lateral retinacular proximal release and "L" type release for lateral patellar compression syndrome. Methods: Sixty four lateral patellar compression syndrome (LPCS) patients were recruited who had arthroscopic surgery during September 2004 to January 2019 at Department of Sports Medicine,Peking University Third Hospital by the same group of doctors and a retrospective comparative study was conducted accordingly. Among them,24 cases underwent the traditional proximal release of lateral patellar retinaculum (traditional group),including 7 males and 17 females with an age of (42.9±14.6)years(range:23 to 72 years); 40 cases were treated with novel lateral retinacular release of "L" type release revised based on the previous experiences (novel group), consisting of 12 males and 28 females with an age of (54.9±13.1) years (range:28 to 76 years).All the patients participated surveys for the visual analogue scale (VAS),Lysholm score and International Knee Documentation Committee (IKDC) knee function subjective evaluation before and after the operation. The comparison of scores within groups was performed by Wilcoxon test,and comparison between groups was performed by Mann-Whitney U test and Chi-square test. Multivariate analysis was used to evaluate the related factors affecting each score. Results: The follow-up durations of traditional group and novel group were (12.6±1.0) years (range:11.7 to 15.3 years) and (2.2±1.0)years(range:1.0 to 4.4 years) respectively. At the last follow-up,VAS(0(1.0)to 6.0(2.0),Z=-5.471,P<0.01),Lysholm score(98.0(10.0)to 48.0(40.0),Z=-5.511,P<0.01),and IKDC score(82.8(11.2)to 37.4(18.5),Z=-5.444,P<0.01) in novel group were statistically significantly improved,and the postoperative excellent rate of Lysholm score was 97.5% in general. There was no significant difference in the changes of the three scores (P>0.05) between the traditional group and the novel group. However,20.8% (5/24)patients in the traditional group reported significant weakness of the knee extension after surgery,while no such complain was received in the novel group (P<0.01).The results of univariate analysis showed that surgical method was a related factor affecting the changes of VAS before and after surgery (P<0.05).The results of multivariate analysis showed that whether or not with osteoarthritis and operation type were independent factors affecting the changes of Lysholm and IKDC scores (P<0.05). Conclusions: The long-term effect of arthroscopic lateral retinacular release for the treatment of LPCS is satisfactory. Compared with the traditional proximal release surgery,the "L" type release can effectively avoid the complication of significant weakness of the knee extension significantly.

[Role of ski injury treatment system between the ski resort medical station of Winter Olympics and the nearby medical care hospital].

OBJECTIVE: To make a retrospective analysis of the situation and process of treating skiers' injuries in the medical station of the Wanlong ski resort in Chongli and the nearest treatment hospital, and to provide a basis for the establishment and optimization of the treatment process between the medical station of the Winter Olympics ski resort and the nearest treatment hospital, and to gain experience for medical security of mass skiing. METHODS: The data of all ski injuries in Chongli District were collected from the medical station of the Wanlong ski resort during the 2018-2019 snow season (November 2018 to April 2019) and the nearest treatment hospital during two periods (March 2019, and November 2019 to January 2020). The differences of injury causes, injury types, injury sites, and treatment effects of the injured skiers were analyzed. RESULTS: A total of 755 cases of ski injuries were recorded in the medical station of Wanlong ski resort, the estimated incidence of injury was 2.02‰ per day. The nearest treatment hospital treated a total of 838 injured skiers from different ski resorts in Chongli District in the two periods. In the records of the ski resort medical station, the main causes of injury were technical defects and turnovers (53.6%). Knee joint injury rate was the highest (18.7%), followed by head and neck (12.9%) and lower limb (11.9%). The number of injuries on intermediate roads was the highest (40.0%), the greatest number of injuries (81.2%) occurred when the age of skiing was less than 5 years. In the records of the nearest treatment hospital, the injury types were fracture or fissure fracture, contusion and trauma, and muscle and soft tissue injury, accounting for 30.5%, 27.4%, and 21.2% respectively. 9.6% of the injured took the snow field ambulance to the hospital, and 50% of them suffered from fractures or fissure fractures. CONCLUSION: The injury rate of skiing in the 2018-2019 snow season of the Wanlong ski resort in Chongli was higher than that reported by foreign literature. Severe trauma (including severe fractures and concussions) could occur and patients needed to be transferred to the nearest hospital for treatment. The ski resort medical station and the nearest treatment hospital should be strengthened with adequate medical staff and equipment, and promote cooperation in the timely referral of seriously injured patients, the organization and construction of ski patrols and the medical security of large-scale competitions, thus playing an important role in forming a grassroots network of medical security and treatment system for skiing.

[Characteristics and related factors of plantar pressure in the chronic ankle instability individuals].

OBJECTIVE: To analyze characteristics and related factors of the plantar pressure during the level walking and single leg standing in the chronic ankle instability (CAI) individuals. METHODS: From April 2019, 75 CAI individuals and 40 healthy individuals were enrolled in this study. Both of the static and dynamic plantar pressure were measured during six times level walking and three times single leg standing testing. The data including peak force, time to peak force in various foot contact areas and the time to boundary (TTB) and velocity of center of pressure (COP) were measured and compared between the affected side and the unaffected side and between the CAI cases and the healthy individuals. The correlations between the plantar pressure and the gender, Beighton score, affected side and body mass index (BMI) were analyzed. RESULTS: The characteristics of plantar pressure distribution in the CAI individuals included: (1) During the level walking, the affected side showed the similar pressure contribution as the unaffected side (P>0.05). While compared with healthy individuals, there was a significantly higher peak force in the 5th metatarsal area (t=-3.86, P=0.03) of the affected side, lower peak force in the 1st (t=2.99, P=0.02), 2nd metatarsal head areas (t=2.09, P=0.01) of the affected side, medial hindfoot areas of both sides (affected, t=2.33, P=0.01; unaffected, t=3.74, P=0.02) and toes areass of both sides (affected, t=2.23, P=0.01; unaffected, t=3.28, P=0.02) and a delay to peak force in the 4th metatarsal head area (t=3.33, P=0.01) of the affected side. (2) During the single leg standing, the CAI individuals showed significantly worse balance control in the anterior/posterior direction (P < 0.05) and lateral/medial direction (P < 0.05) compared with the healthy controls, and the affected side had more severe balance control deficit in the lateral/medial direction (P < 0.05). (3) The women (P < 0.05) and the individuals with higher Beighton scores (P < 0.05) showed worse balance control deficit in the lateral/medial direction. CONCLUSION: CAI individuals showed significantly a more lateral shifted plantar distribution during the level walking compared with the healthy individuals and the tendency was worse on the affected sides, and showed worse balance control in the anterior/posterior direction and lateral/medial direction during the single leg standing. The women and those with generalized ligament laxity showed significantly worse balance control.

[Analysis of the mass skiers' injury in a large ski resort in Chongli, China].

OBJECTIVE: To make a retrospective analysis of the injuries of skiing population in a large ski resort in Chongli, China and provide a basis for predicting the rapidly increasing medical needs for ski injuries in the context of the 2022 Winter Olympic Games. METHODS: The basic data of all injured skiers who were treated in a medical station of a large ski resort in Chongli during the snow season from November 2017 to March 2018 and from November 2018 to March 2019 were collected. The number of skiers, the number of injuries, the causes of injuries, the types of injuries and the locations of injuries were compared. RESULTS: A total of 753 skiers were injured in two snow seasons, and the estimated average incidence of injury was 4.53 and 4.46 per 1 000 skier days at the resort respectively. The average daily injury rate per 1 000 skiers in November of the two snow seasons was relatively low, with 2.20 and 1.38 cases respectively. The difference of injury rate in different months might have little to do with snowfall and more to do with passenger flow. In both the snow seasons, men accounted for more injuries than women, and injured skiers aged between 21 and 30 accounted for the largest proportion, reaching 36.8%. The main causes of injuries were falls (76.6%). The highest rate of injury was in the head and neck (17.9%), followed by the knee (17.4%) and wrist and fingers (13.3%). The most common types of injuries were contusion and trauma (29.5%) and joint and/or ligament injuries (22.2%). Children (2-12 years old) accounted for 12.7% of all the injured skiers. The rate of moderate to severe injuries (including fractures, concussions, etc.) was 34.8% among the injured patients over 50 years of age. CONCLUSION: The snow resort should focus on injuries to children and elderly skiers and carry out targeted guidance and rescue work. In order to better ensure the medical safety of skiers, the ski resort medical station and nearby treatment hospitals should be equipped with a corresponding number of medical personnel and equipment, and the ski resort should further improve its safety management and rescue system.

[Analysis of factors influencing the efficacy of extracapsular arthroscopic surgery for refractory tennis elbow].

Objective: To investigate the mid-term efficacy of extracapsular arthroscopic surgery for refractory tennis elbow and explore prognostic factors. Methods: A retrospective study of 38 patients suffered from refractory tennis elbow and underwent extracapsular arthroscopic surgery performed by the same group of doctors during March 2012 to January 2016 at Institute of Sports Medicine, Peking University Third Hospital. There were 15 males and 23 females with age of 44.2 years(range: 32-59 years). Fifteen cases on the left and 23 cases on the right. Visual analogue scale(VAS), Mayo elbow performance score and Disability of Army, Shoulder and Hand (DASH) score were collected preoperatively and postoperatively, and compared by paired-t test. Independent sample t test, χ(2) test, multivariate logistic regression were used to analyze the relationship between scores and various potential influencing factors. Results: All 38 patients were followed up for 24 months. There was no complication such as infection or nerve injury recorded. VAS decreased from 7.0(1.2) (M(Q(R))) preoperative to 0(1) (Z=-5.40, P=0.00), Mayo increased from 55(26) to 100(0) (Z=-5.38, P=0.00),DASH decreased from 56.7(27.3) to 0.8(5.8)(Z=-5.37,P=0.00). The Mayo elbow performance score was excellent in 36 cases (94.7%) and good in 2 cases (5.3%). Women was significantly associated with poor prognosis. Conclusions: The mid-term effect of extracapsular arthroscopic treatment of refractory tennis elbow is satisfactory with few postoperative complications. Women was associated with poor prognosis.

[Surgical technique and mid-and-long curative effect analysis of primary repair of chronic Achilles tendon rupture].

Objective: To examine the surgical method and clinical outcome of primary repair of chronic Achilles tendon rupture. Methods: From March 2012 to August 2017, clinical data of 35 consecutive patients with chronic Achilles tendon rupture who were treated with primary repair by the same doctor at Department of Sports Medicine, Peking University Third Hospital were retrospectively analyzed.There were 29 males and 6 females with age of (41.0±9.3)years(range:29-65 years), the follow-up period was (45.6±17.2) months(range:17-82 months). All the patients had unilateral tendon rupture with 22 cases on the left and 13 cases on the right.The preoperative and postoperative Visual Analogue Scale(VAS), American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Score(AOFAS), the Victorian Institute of Sport Assessment-Achilles(VISA-A), the Achilles tendon Total Rupture Score(ATRS)and the Tegner Activity Score of patients were collected and compared by paired-t test. Results: Among 47 patients with chronic Achilles tendon rupture, 35 patients were followed up for (45.6 ± 17.2)months(range: 17-28 months). No serious postoperative complications such as infection or nerve damage and rerupture outcomes were reported. At the last follow-up,the VAS decreased from 1.0(2.0) (M(Q(R))) preoperative to 0.0(0.8)(Z=-3.586, P=0.00), AOFAS increased from 64.3±12.5 to 97.0±5.0(t=-14.359,P<0.001), VISA-A increased from 51.3± 9.8 to 87.8±18.0(t=- 17.656, P=0.00), Tegner increased from 0.9±0.3 to 4.6±1.7(t=- 12.524, P=0.00)and ATRS increased from 40.0±3.5 to 97.9±3.9(t=-64.133,P=0.00). Twenty-eight patients (80.0%) had returned to their preinjury activity levels, and 7 patients (20.0%) no longer participate in recreational sports. According to Arner-Lindholm curative effect evaluation criteria, 32 cases(91.4%)gained the excellent results, 1 case(2.9%) of good and 2 cases(5.7%) bad, and the percentage of the cases with the excellent or good results was 94.3%. All except 2 patients with bad results could perform a single-limb heel rise painlessly. Conclusions: Primary repair is an efficient approach for chronic Achilles tendon rupture. The mid-and-long curative effect is satisfactory and stable.Compared with other surgical techniques, operation is relatively simple and economical. The primary repair is considerably safe, with few serious complications such as infection or nerve damage and reruptures.

[Anatomical and finite element analysis of anterior cruciate ligament reconstruction within biomechanical insertion].

OBJECTIVE: To provide new concepts of anterior cruciate ligament (ACL) reconstruction by anatomical gross observation of ACL tibial insertion and finite element analysis of distribution of ACL mechanical insertion. METHODS: In the anatomical study, ten fresh adult cadaveric knees were dissected, including 6 males and 4 females, all knees were generally observed through standard medial parapatellar approaches, paying attention to the close anatomical relationship of tibial insertion and anterior horn of lateral meniscus, and ACL was exposed and gradually removed from the inside. The shape of tibial insertion of ACL was observed and recorded, and anterior-posterior diameters and left-right diameters of tibial insertion were measured with vernier caliper. For the study of finite element analysis, three-dimensional thin-layer magnetic resonance imaging of normal knee joint was used to establish knee joint model. Three-dimensional reconstruction software MIMICS and finite element analysis software ANSYS were used to establish knee joint model, subsequently, clinical physical examination Lachman test and pivot-shift test were simulated to observe the force distribution of ACL tibial insertion and femoral insertion. RESULTS: The ACL tibial mechanical insertion was rather flat and long similar as an arc shape without a clear separation between anterior medial bundle (AMB) and posterolateral bundle (PLB) in gross observation. The dense fibers lies belonged to the medial intercondylar ridge and ended up anterior with the osseous landmark of anterior ridge. Its average anterior-posterior diameter was (13.8±2.0) mm, the average left-right diameter of midsubstance was (5.3±0.6) mm, and the average left-right diameter of anterior margin was (11.5±1.2) mm. The finite element analysis showed that distribution on the femoral side was oval shape mainly below the residents' ridge, while the tibial side was rather flat mainly along the medial intercondylar ridge, which was consistent with the anatomical observation. The biomechanical characteristics of ACL attachments were verified theoretically. CONCLUSION: Anatomical study and finite element analysis have confirmed the flat arc shape of ACL tibial insertion. The ideal reconstruction technique of ACL should be based on its biomechanical insertion. Based on anatomical study and biomechanical analysis, we have proposed the idea of ACL biomechanical insertion reconstruction (BIR) and established a surgical model with oval femoral tunnel and rounded-rectangle tibial tunnel.

Runx2 overexpression enhances osteoblastic differentiation and mineralization in adipose--derived stem cells in vitro and in vivo.

Like bone marrow stromal cells, adipose tissue-derived stem cells (ADSCs) possess multilineage potential, a capacity for self-renewal and long-term viability. To confirm whether ADSCs represent a promising source of cells for gene-enhanced bone tissue-engineering, the osteogenic potential of ADSCs under the control of certain osteoinductive genes has been evaluated. Runx2, a transcription factor at the downstream end of bone morphogenetic protein (BMP) signaling pathways, is essential for osteoblast differentiation and bone formation. In this study we used adenovirus vector to deliver Runx2 to ADSCs and then examined the enhancement of osteogenic activity. Overexpression of Runx2 inhibited adipogenesis, as demonstrated by suppression of LPL and PPARgamma expression at the mRNA level and reduced lipid droplet formation. Moreover, ADSCs transduced with Ad-Runx2 underwent rapid and marked osteoblast differentiation as determined by osteoblastic gene expression, alkaline phosphatase activity and mineral deposition. Additionally, histological examination revealed that implantation of Runx2 modified ADSCs could induce mineral deposition and bone-like tissue formation in vivo. These results confirmed, firstly, the ability of Runx2 to promote osteogenesis and cell differentiation and, secondly, the competence of ADSCs as target cells for bone tissue engineering. Our work demonstrates a potential new approach for bone repair using Runx2-modified ADSCs for bone tissue engineering.

[Diagnosis and treatment of closed complete rupture of patellar tendon. Analysis of 11 cases].

Eleven cases of closed complete rupture of patellar tendon (4 neglected ruptures and 7 fresh ruptures) were treated. Seven of them were treated in extension for 6-8 weeks after operation, 1 was immobilized with patellar traction in the early stage on bed, and 3 were mobilized and assisted with movable brace standing and walking through the body weigh on the knee in the early stage after operation. The aim was to promote the functional recovery of the knee joint. The mechanism of injury, clinical diagnosis, treatment and rehabilitation of closed rupture of patellar tendon were discussed in combination with clinical experience. And the suggestion of movement and active recovery in the early stage after patellar tendon surgery was put forward.

[Contractile function of the gallbladder after gastrectomy].

Gallbladder contractile function was observed by B-mode ultrasonography on patients with radical gastrectomy for gastric carcinoma (20 cases), with subtotal gastrectomy for peptic ulcer (36 cases), and with highly selective vagotomy (7 cases). Thirty-one preoperative patients with peptic ulcer were used as control. It was found that within one month after radical or subtotal gastrectomy the average area and the volume of the gallbladder became much larger than that found in control group. The empty rate of the gallbladder was found decreased and the remainder bile increased. Early stage gallstones were found in two cases 11 and 13 months after gastrectomy. The inner diameter of the common bile duct was increased after radical gastrectomy. No definite relationship was found between gallbladder contractile disfunction and the mode of gastroenterostomy. It was also found that highly selective vagotomy had only slight influence on the biliary tract. These results suggest that gastrectomy has significant influence on the function of biliary tract and plays an important role in the formation of gallstones.