The December 2023 Hip & Pelvis Roundup. 360. looks at: Early hip fracture surgery is safe for patients on direct oral anticoagulants; Time to return to work by occupational class after total hip or knee arthroplasty; Is there a consensus on air travel following hip and knee arthroplasty?; Predicting whether patients will achieve minimal clinically important differences following hip or knee arthroplasty; High-dose dual-antibiotic-loaded cement for hip hemiarthroplasty in the UK (WHiTE 8): a randomized controlled trial; Vitamin E – a positive thing in your poly?; Hydroxapatite-coated femoral stems: is there a difference in fixation?

The February 2023 Hip & Pelvis Roundup. 360. looks at: Total hip arthroplasty or internal fixation for hip fracture?; Significant deterioration in quality of life and increased frailty in patients waiting more than six months for total hip or knee arthroplasty: a cross-sectional multicentre study; Long-term cognitive trajectory after total joint arthroplasty; Costal cartilage grafting for a large osteochondral lesion of the femoral head; Foley catheters not a problem in the short term; Revision hips still a mortality burden?; How to position implants with a robotic arm; Uncemented stems in hip fracture?

The June 2023 Hip & Pelvis Roundup. 360. looks at: Machine learning to identify surgical candidates for hip and knee arthroplasty: a viable option?; Poor outcome after debridement and implant retention; Can you cement polyethylene liners into well-fixed acetabular shells in hip revision?; Revision stem in primary arthroplasties: the Exeter 44/0 125 mm stem; Depression and anxiety: could they be linked to infection?; Does where you live affect your outcomes after hip and knee arthroplasties?; Racial disparities in outcomes after total hip arthroplasty and total knee arthroplasty are substantially mediated by socioeconomic disadvantage both in black and white patients

The June 2024 Hip & Pelvis Roundup. 360. looks at: Machine learning did not outperform conventional competing risk modelling to predict revision arthroplasty; Unravelling the risks: incidence and reoperation rates for femoral fractures post-total hip arthroplasty; Spinal versus general anaesthesia for hip arthroscopy: a COVID-19 pandemic- and opioid epidemic-driven study; Development and validation of a deep-learning model to predict total hip arthroplasty on radiographs; Ambulatory centres lead in same-day hip and knee arthroplasty success; Exploring the impact of smokeless tobacco on total hip arthroplasty outcomes: a deeper dive into postoperative complications

The August 2023 Hip & Pelvis Roundup. 360. looks at: Using machine learning to predict venous thromboembolism and major bleeding events following total joint arthroplasty; Antibiotic length in revision total hip arthroplasty; Preoperative colonization and worse outcomes; Short stem cemented total hip arthroplasty; What are the outcomes of one- versus two-stage revisions in the UK?; To cement or not to cement? The best approach in hemiarthroplasty; Similar re-revisions in cemented and cementless femoral revisions for periprosthetic femoral fractures in total hip arthroplasty; Are hip precautions still needed?

The October 2023 Hip & Pelvis Roundup. 360. looks at: Femoroacetabular impingement syndrome at ten years – how do athletes do?; Venous thromboembolism in patients following total joint replacement: are transfusions to blame?; What changes in pelvic sagittal tilt occur 20 years after total hip arthroplasty?; Can stratified care in hip arthroscopy predict successful and unsuccessful outcomes?; Hip replacement into your nineties; Can large language models help with follow-up?; The most taxing of revisions – proximal femoral replacement for periprosthetic joint infection – what’s the benefit of dual mobility?

The December 2022 Hip & Pelvis Roundup. 360. looks at: Fix and replace: simultaneous fracture fixation and hip arthroplasty for acetabular fractures in older patients; Is the revision rate for femoral neck fracture lower for total hip arthroplasty than for hemiarthroplasty?; Femoral periprosthetic fractures: data from the COMPOSE cohort study; Dual-mobility cups and fracture of the femur; What’s the deal with outcomes for hip and knee arthroplasty outcomes internationally?; Osteochondral lesions of the femoral head: is costal cartilage the answer?

The April 2024 Hip & Pelvis Roundup. 360. looks at: Impaction bone grafting for femoral revision hip arthroplasty with the Exeter stem; Effect of preoperative corticosteroids on postoperative glucose control in total joint replacement; Tranexamic acid in patients with a history of venous thromboembolism; Bisphosphonate use may be associated with an increased risk of periprosthetic hip fracture; A balanced approach: exploring the impact of surgical techniques on hip arthroplasty outcomes; A leap forward in hip arthroplasty: dual-mobility bearings reduce groin pain; A new perspective on complications: the link between blood glucose and joint infection risks

The February 2024 Hip & Pelvis Roundup. 360. looks at: Trial of vancomycin and cefazolin as surgical prophylaxis in arthroplasty; Is preoperative posterior femoral neck tilt a risk factor for fixation failure? Cemented versus uncemented hemiarthroplasty for displaced intracapsular fractures of the hip; Periprosthetic fractures in larger hydroxyapatite-coated stems: are collared stems a better alternative for total hip arthroplasty?; Postoperative periprosthetic fracture following hip arthroplasty with a polished taper slip versus composite beam stem; Is oral tranexamic acid as good as intravenous?; Stem design and the risk of early periprosthetic femur fractures following THA in elderly patients; Does powered femoral broaching compromise patient safety in total hip arthroplasty?

The April 2023 Hip & Pelvis Roundup. 360. looks at: Do technical errors determine outcomes of operatively managed femoral neck fractures in younger adults?; Single-stage or two-stage revision for hip prosthetic joint infection (INFORM); Fixation better than revision in type B periprosthetic fractures of taper slip stems; Can you maximize femoral head size at the expense of liner thickness?; Plasma D-dimer for periprosthetic joint infection?; How important is in vivo oxidation?; Total hip arthroplasty for HIV patients with osteonecrosis

The October 2024 Hip & Pelvis Roundup. 360. looks at: Does the primary surgical approach matter when choosing the approach for revision total hip arthroplasty?; Time to achieve the minimal clinically important difference in primary total hip arthroplasty: comparison of anterior and posterior surgical approaches; To scope or not to scope: arthroscopy as an adjunct to PAO does not provide better clinical outcomes at one year than PAO alone; Re-exploring horizons in hip resurfacing: two-year results of a ceramic-on-ceramic hip resurfacing; Association between tranexamic acid and decreased periprosthetic joint infection risk in patients undergoing total hip and knee arthroplasty; Octogenarians fare well: in revision for infection age is not a bar

The August 2024 Hip & Pelvis Roundup. 360. looks at: Understanding perceived leg length discrepancy post-total hip arthroplasty: the role of pelvic obliquity; Influence of femoral stem design on revision rates in total hip arthroplasty; Outcomes of arthroscopic labral treatment of femoroacetabular impingement in adolescents; Characteristics and quality of online searches for direct anterior versus posterior approach for total hip arthroplasty; Rapid return to braking after anterior and posterior approach total hip arthroplasty; How much protection does a collar provide?; Timing matters: reducing infection risk in total hip arthroplasty with corticosteroid injection intervals; Identifying pain recovery patterns in total hip arthroplasty using PROMIS data

The August 2015 Hip & Pelvis Roundup. 360 . looks at: The well-fixed acetabular revision; Predicting complications in revision arthroplasty; Is infection associated with fixation?; Front or back? An enduring question in hip surgery; Muscle-sparing approaches?; Gabapentin as a post-operative analgesic adjunct; An Indian take on AVN of the hip; Weight loss and arthroplasty

The June 2015 Hip & Pelvis Roundup. 360 . looks at: neuraxial anaesthesia and large joint arthroplasty; revision total hip arthoplasty: factors associated with re-revision surgery; acetabular version and clinical outcomes in impingement surgery; hip precautions may be ineffective; implant selection and cost effectiveness; femoroacetabular impingement in the older age group; multiple revision in hip arthroplasty

The October 2014 Hip & Pelvis Roundup. 360 . looks at: functional acetabular orientation; predicting re-admission following THR; metal ions and resurfacing; lipped liners increase stability; all anaesthetics equal in hip fracture surgery; revision hip surgery in very young patients; and uncemented hips

The December 2015 Hip & Pelvis Roundup. 360 . looks at: Vitamin E infusion helpful in polyethylene; Hip replacement in fracture and arthritis; Non-surgical treatment for arthritis; Cost and approach in hip surgery; Who does well in FAI surgery?; AAOS Thromboembolism guidelines; Thromboprophylaxis and periprosthetic joint infection; Fluid collections not limited to metal-on-metal THR

The August 2013 Hip & Pelvis Roundup. 360 . looks at: are we getting it right first time?; tantalum augments in revision hip surgery; lower wear in dual mobility?; changing faces changes outcomes; synovial fluid aspiration in MOM hips; taper disease: the new epidemic of hip surgery; the super-obese and THR; and whether well fixed stems can remain in infected hips

The December 2014 Hip & Pelvis Roundup. 360 . looks at: Sports and total hips; topical tranexamic acid and blood conservation in hip replacement; blind spots and biases in hip research; no recurrence in cam lesions at two years; to drain or not to drain?; sonication and diagnosis of implant associated infection; and biomarkers and periprosthetic infection

The April 2015 Hip & Pelvis Roundup. 360 . looks at: Goal-directed fluid therapy in hip fracture; Liberal blood transfusion no benefit in the longer term; Repeated measures: increased accuracy or compounded errors?; Peri-acetabular osteotomy safer than perhaps thought?; Obesity and peri-acetabular osteotomy: poor bedfellows; Stress fracture in peri-acetabular osteotomy; Infection and tantalum implants; Highly crosslinked polyethylene really does work

The February 2015 Hip & Pelvis Roundup. 360 . looks at: Hip arthroplasty in Down syndrome; Bulk femoral autograft successful in acetabular reconstruction; Arthroplasty follow-up: is the internet the solution?; Total hip arthroplasty following acetabular fracture; Salvage arthroplasty following failed hip internal fixation; Bone banking sensible financially and clinically; Allogenic blood transfusion in arthroplasty

The June 2012 Hip & Pelvis Roundup. 360. looks at: whether metal-on-metal is really such a disaster; resurfacings with unexplained pain; large heads and high ion levels; hip arthroscopy for FAI; the inaccuracy of clinical tests for impingement; arthroscopic lengthening of iliopsoas; the OA hip; the injured hamstring – football’s most common injury; an algorithm for hip fracture surgery; and sparing piriformis at THR

The June 2013 Hip & Pelvis Roundup. 360 . looks at: failure in metal-on-metal arthroplasty; minimal hip approaches; whether bisphosphonates improve femoral bone stock following arthroplasty; whether more fat means more operative time; surgical infection; vascularised fibular graft for osteonecrosis; subclinical SUFE; and dentists, hips and antibiotics

The August 2014 Hip & Pelvis Roundup. 360 . looks at: Serial MRIs best for pseudotumour surveillance; Is ultrasound good enough for MOM follow-up?; Does weight loss in obese patients help?; Measuring acetabular anteversion on plain films; Two-stage one-stage too many in fungal hip revisions? and 35 is the magic number in arthroplasty

The June 2014 Hip & Pelvis Roundup. 360 . looks at: Modular femoral necks: early signs are not good; is corrosion to blame for modular neck failures; metal-on-metal is not quite a closed book; no excess failures in fixation of displaced femoral neck fractures; noise no problem in hip replacement; heterotopic ossification after hip arthroscopy: are NSAIDs the answer?; thrombotic and bleeding events surprisingly low in total joint replacement; and the elephant in the room: complications and surgical volume

The February 2014 Hip & Pelvis Roundup. 360 . looks at: length of stay; cementless metaphyseal fixation; mortality trends in over 400,000 total hip replacements; antibiotics in hip fracture surgery; blood supply to the femoral head after dislocation; resurfacing and THR in metal-on-metal replacement; diabetes and hip replacement; bone remodelling over two decades following hip replacement; and whether bisphosphonates affect acetabular fixation

The April 2013 Hip & Pelvis Roundup. 360 . looks at: hip cartilage and magnets; labral repair or resection; who benefits from injection; rotational osteotomy for osteonecrosis; whether ceramic implants risk fracture; dual articulation; and hydroxyapatite

The October 2015 Hip & Pelvis Roundup. 360 . looks at: Smoking and complications in arthroplasty; Smoking cessation beneficial in arthroplasty; Intermediate care and arthroplasty; Do we still need cell salvage?; Femoroacetabular impingement in the Japanese population; Trunnionosis or taperosis and geometry; Decontamination for staphylococcus aureus works!; Policeman or opportunity? Quality improvement with registries; Death rates higher in readmission to other hospitals

The February 2013 Hip & Pelvis Roundup. 360 . looks at: amazing alumina; dual mobility; white cells and periprosthetic infection; cartilage and impingement surgery; acetabulum in combination; cementless ceramic prosthesis; metal-on-metal hips; and whether size matters in failure

The December 2012 Hip & Pelvis Roundup. 360 . looks at: swimming against the tide with resurfacing; hip impingement surgery; the relationship between obesity and co-morbidities and joint replacement infection; cemented hips; cross-linked polyethylene notching; whether cement is necessary in oncological arthroplasty; and how total hip replacement may result in weight gain

The August 2012 Hip & Pelvis Roundup. 360. looks at: whether cemented hip replacement might be bad for your health; highly cross-linked polyethylene; iHOT-33 - a new hip outcome measure; hamstring injuries; total hip replacement; stemmed metal-on-metal THR; bipolar hemiarthroplasty, neuromuscular disease and dislocation; the high risk of secondary hemiarthroplasty; and whether we have to repair the labrum after all?

The April 2012 Hip & Pelvis Roundup. 360. looks at osteoporotic hip fractures, retrotrochanteric pain, fibrin adhesive and reattachment of articular cartilage, autologous bone marrow mononuclear cells and avascular necrosis, bearing surfaces, stability after THR, digital templating, pelvic tilt after THR, custom-made sockets for DDH, and dogs and THR

The April 2014 Hip & Pelvis Roundup. 360 . looks at: Recent arthroplasty and flight; whether that squeak could be a fracture; diagnosing early infected hip replacement; impaction grafting at a decade; whether squeaking is more common than previously thought; femoral offset associated with post THR outcomes; and periprosthetic fracture stabilisation

The December 2013 Hip & Pelvis Roundup. 360 . looks at: Enhanced recovery works; Acetabular placement; Exercise better than rest in osteoarthritis patients; if Birmingham hip resurfacing is immune from pseudotumour; HIV and arthroplasty; Labral tears revisited; Prophylactic surgery for FAI; and Ceramics and impaction grafting

The October 2013 Hip & Pelvis Roundup. 360 . looks at: Young and impinging; Clothes, weather and femoral heads?; Go long, go cemented; Surgical repair of the abductors?; Aspirin for DVT prophylaxis?; Ceramic-on-polyethylene: a low-wear solution?; ALVAL and ASR™: the story continues….; Salvaging Legg-Calve-Perthes’ disease

The October 2012 Hip & Pelvis Roundup. 360. looks at: diagnosing the infected hip replacement; whether tranexamic acid has a low complication rate; the relationship between poor cementing technique and early failure of resurfacing; debridement and retention for the infected replacement; triple-tapered stems and bone mineral density; how early discharge can be bad for your sleep; an updated QFracture algorithm to predict the risk of an osteoporotic fracture; and local infiltration analgesia and total hip replacement

The April 2024 Trauma Roundup. 360. looks at: The infra-acetabular screw in acetabular fracture surgery; Is skin traction helpful in patients with intertrochanteric hip fractures?; Reducing pain and improving function following hip fracture surgery; Are postoperative splints helpful following ankle fracture fixation?; Biomechanics of internal fixation in Hoffa fractures: a comparison of four different constructs; Dual-plate fixation of periprosthetic distal femur fractures; Do direct oral anticoagulants necessarily mean a delay to hip fracture surgery?; Plate or retrograde nail for low distal femur fractures?

The June 2023 Trauma Roundup. 360. looks at: Aspirin or low-molecular-weight heparin for thromboprophylaxis?; Lateral plating or retrograde nailing for distal femur fractures?; Sciatic nerve palsy after acetabular fixation: what about patient position?; How reliable is the new OTA/AO classification for trochanteric hip fractures?; Young hip fractures: is a medial buttress the answer?; When is the best time to ‘flap’ an open fracture?; The mortality burden of nonoperatively managed hip fractures

The August 2023 Children’s orthopaedics Roundup. 360. looks at: DDH: What can patients expect after open reduction?; Femoral head deformity associated with hip displacement in non-ambulatory cerebral palsy; Bony hip reconstruction for displaced hips in patients with cerebral palsy: is postoperative immobilization indicated?; Opioid re-prescriptions after ACL reconstruction in adolescents are associated with subsequent opioid use disorder; Normative femoral and tibial lengths in a modern population of USA children; Retrospective analysis of associated anomalies in 636 patients with operatively treated congenital scoliosis; Radiological hip shape and patient-reported outcome measures in healed Perthes’ disease; Significantly displaced adolescent posterior sternoclavicular joint injuries

The October 2024 Research Roundup. 360. looks at: Fracture risk among stroke survivors according to post-stroke disability status and stroke type; Noise-induced hearing loss: should surgeons be wearing ear protection during primary total joint replacement?; Intravenous dexamethasone in hip arthroscopy can enhance recovery; Patient-reported outcomes following periprosthetic joint infection of the hip and knee: a longitudinal, prospective observational study; When should surgery take place after weight loss?; Which type of surgery is the hardest physically and mentally?

This edition of Cochrane Corner looks at some of the work published by the Cochrane Collaboration, covering pharmacological interventions for the prevention of bleeding in people undergoing definitive fixation or joint replacement for hip, pelvic, and long bone fractures; interventions for reducing red blood cell transfusion in adults undergoing hip fracture surgery: an overview of systematic reviews; and pharmacological treatments for low back pain in adults: an overview of Cochrane Reviews

The October 2023 Trauma Roundup. 360. looks at: Intramedullary nailing versus sliding hip screw in trochanteric fracture management: the INSITE randomized clinical trial; Five-year outcomes for patients with a displaced fracture of the distal tibia; Direct anterior versus anterolateral approach in hip joint hemiarthroplasty; Proximal humerus fractures: treat them all nonoperatively?; Tranexamic acid administration by prehospital personnel; Locked plating versus nailing for proximal tibia fractures: a multicentre randomized controlled trial; A retrospective review of the rate of septic knee arthritis after retrograde femoral nailing for traumatic femoral fractures at a single academic institution

The December 2022 Sports Roundup. 360. looks at: Anterior cruciate ligament (ACL) repair with dynamic intraligamentary stabilization or anterior ACL at five years?; Femoroacetabular impingement in mild osteoarthritis: is hip arthroscopy the answer?; Steroids in Achilles tendinopathy: A randomized trial

The December 2023 Spine Roundup. 360. looks at: Does size matter in adolescent pedicle screws?; Effect of lumbar fusion and pelvic fixation rigidity on hip joint stress: a finite element analysis; Utility of ultrasonography in the diagnosis of lumbar spondylolysis in adolescent patients; Rett syndrome-associated scoliosis a national picture

The February 2024 Children’s orthopaedics Roundup. 360. looks at: Hip impingement after in situ pinning causes decreased flexion and forced external rotation in flexion on 3D-CT; Triplane ankle fracture patterns in paediatric patients; Improved forearm rotation even after early conversion to below-elbow; Selective dorsal rhizotomy and cerebral palsy (CP) hip displacement; Abduction bracing following anterior open reduction for developmental dysplasia of the hip does not improve residual dysplasia or reduce secondary surgery; 40% risk of later total hip arthroplasty for in situ slipped capital femoral epiphysis (SCFE) pinning; Does brace treatment following closed reduction of developmental dysplasia of the hip improve acetabular coverage?; Waterproof hip spica casts for paediatric femur fractures

The February 2023 Trauma Roundup. 360. looks at: Masquelet versus bone transport in infected nonunion of tibia; Hyperbaric Oxygen for Lower Limb Trauma (HOLLT): an international multicentre randomized clinical trial; Is the T-shaped acetabular fracture really a “T”?; What causes cut-out of proximal femur nail anti-rotation device in intertrochanteric fractures?; Is the common femoral artery at risk with percutaneous fragility pelvis fixation?; Anterior pelvic ring pattern predicts displacement in lateral compression fractures; Differences in age-related characteristics among elderly patients with hip fractures

The October 2023 Research Roundup. 360. looks at: Gut microbiota in high-risk individuals for rheumatoid arthritis associated with disturbed metabolome and initiates arthritis by triggering mucosal immunity imbalance; International Consensus on Anaemia Management in Surgical Patients (ICCAMS); Sleep disturbance trends in the short-term postoperative period for patients undergoing total joint replacement; Achilles tendon tissue turnover before and immediately after an acute rupture; Quadriceps or hip exercises for patellofemoral pain? A randomized controlled equivalence trial; Total-body MRI for screening in patients with multiple osteochondromas

The August 2024 Children’s orthopaedics Roundup. 360. looks at: Antibiotic prophylaxis and infection rates in paediatric supracondylar humerus fractures; Clinical consensus recommendations for the non-surgical treatment of children with Perthes’ disease in the UK; Health-related quality of life in idiopathic toe walkers: a multicentre prospective cross-sectional study; Children with spinal dysraphism: a systematic review of reported outcomes; No delay in age of crawling, standing, or walking with Pavlik harness treatment: a prospective cohort study; No value found with routine early postoperative radiographs after implant removal in paediatric patients; What do we know about the natural history of spastic hip dysplasia and pain in total-involvement cerebral palsy?; Evaluating the efficacy and safety of preoperative gallows traction for hip open reduction in infants

The April 2023 Children’s orthopaedics Roundup. 360. looks at: CT scan of the ipsilateral femoral neck in paediatric shaft fractures; Meniscal injuries in skeletally immature children with tibial eminence fractures: a systematic literature review; Post-maturity progression in adolescent idiopathic scoliosis curves of 40° to 50°; Prospective, randomized Ponseti treatment for clubfoot: orthopaedic surgeons versus physical therapists; FIFA 11+ Kids: challenges in implementing a prevention programme; The management of developmental dysplasia of the hip in children aged under three months: a consensus study from the British Society for Children's Orthopaedic Surgery; Early investigation and bracing in developmental dysplasia of the hip impacts maternal wellbeing and breastfeeding; Hip arthrodesis in children: a review of 26 cases with a mean of 20 years’ follow-up

The August 2023 Trauma Roundup. 360. looks at: A comparison of functional cast and volar-flexion ulnar deviation for dorsally displaced distal radius fractures; Give your stable ankle fractures some AIR!; Early stabilization of rib fractures – an effective thing to do?; Locked plating versus nailing for proximal tibia fractures: A multicentre randomized controlled trial; Time to flap coverage in open tibia fractures; Does tranexamic acid affect the incidence of heterotropic ossification around the elbow?; High BMI – good or bad in surgical fixation of hip fractures?

The June 2024 Children’s orthopaedics Roundup. 360. looks at: Proximal femoral unicameral bone cysts: is ESIN the answer?; Hybrid-mesh casts in the conservative management of paediatric supracondylar humeral fractures: a randomized controlled trial; Rate and risk factors for contralateral slippage in adolescents treated for slipped capital femoral epiphysis; CRP predicts the need to escalate care after initial debridement for musculoskeletal infection; Genu valgum in paediatric patients presenting with patellofemoral instability; Nusinersen therapy changed the natural course of spinal muscular atrophy type 1: what about spine and hip?; The necessity of ulnar nerve exploration and translocation in open reduction of medial humeral epicondyle fractures in children

The April 2023 Knee Roundup. 360. looks at: Does bariatric surgery reduce complications after total knee arthroplasty?; Mid-flexion stability in total knee arthroplasties implanted with kinematic alignment: posterior-stabilized versus medial-stabilized implants; Inflammatory response in robotic-arm-assisted versus conventional jig-based total knee arthroplasty; Journey II bicruciate stabilized (JII-BCS) and GENESIS II total knee arthroplasty: the CAPAbility, blinded, randomized controlled trial; Lifetime risk of revision and patient factors; Platelet-rich plasma use for hip and knee osteoarthritis in the USA; Where have the knee revisions gone?; Tibial component rotation in total knee arthroplasty: CT-based study of 1,351 tibiae

The October 2024 Knee Roundup. 360. looks at: Managing the unexpected: treatment of intraoperative medial collateral ligament injuries; Identifying subgroups of patients that may benefit from robotic arm-assisted total knee arthroplasty: secondary analysis of data from a randomized controlled trial; Cost-effectiveness of enoxaparin versus aspirin in the prevention of venous thromboembolism after total hip or knee arthroplasty: an analysis from the CRISTAL cluster-randomized trial; Cartilage regeneration and long-term survival in medial knee osteoarthritis patients treated with high tibial osteotomy and osteochondral autologous transfer system; Treatment of chronic and complex meniscal tears with arthroscopic meniscus repair augmented with collagen matrix wrapping: failure rate and functional outcomes; Long-term outcomes of multiligament knee injuries in American football players