Injury type	Incidence/ Prevalence	Risk factors for this injury	Risk factors for OA	Risk of OA compared to uninjured subjects.
Meniscal injury	Incidence of 0.3-0.7/ 1000 inhabitants.	Male gender Sports	Severity of the meniscal damage. Meniscectomy Female sex and age > 40 years Obesity	Increased risk from OR=3 mild to OR 7.9 (4.4-14) for severe meniscal damage. After 19 years risk of OA increased by 11%., 24% after four years and 71% after 20 years.
Proximal Tibial Fractures (PTF)	Incidence of 0.1-0.13 per 1000 inhabitants	Males younger than 50 years. Accidents and high-energy traumas. More severe fractures in patients older than 50 years.	Operative treatment: High age principally in treated fractures. In younger patients: bicondylar fractures. Osteoporosis and other comorbidities including a high BMI. Malalignment of the knee, deviation of the mechanical axis in varus, articular step-off and meniscus lesion The severity of the lesion: Fracture comminution and articular collapse. Female sex. It is higher during the first years than at long term.	PTOA is generally estimated to occur in 23% to 36% of cases following an intra-articular fracture. Between 21–75% of cases after operative treatment develop PTOA even when adequate reduction and stable fixation have been achieved. Severe OA leading to TKR develops in 2.2–7.5% of operatively treated patients after 2 to 5 years post-trauma. Compared with all populations, these patients are at a 3.5 to 5.3-fold higher risk of end-stage PTOA requiring TKR. Radiological signs of OA were reported in 10% to 83% of studied cases.
Patellar dislocation	Between 0.058-0.070 per 1000 person-years.	Active young individuals practicing sports. Decreased depth, a flat or even convex trochlear surface. Females have a 33% higher risk of patellar instability and dislocation than males. Military personal.	Patellofemoral instability due to recurrent dislocation. Increases over time. osteochondral injury and trochlear dysplasia. Female sex and older age.	The risk of OA increases with the number of years after dislocation, from non-significant increase till 22% at t13 years, and it achieves 50% after 25 years of follow-up.
Acetabular fractures	Around 8.1/100,000 persons/year in Europe	High energy trauma and accidents in the young population and low energy trauma such as falling in the elderly.	Residual articular incongruity, quality of fracture reduction. Column fractures, posterior wall and type A1 fracture. Male sex. Age older than 40 years. Obesity Associated chondral or osseous lesions of the femoral head. Involvement of the posterior wall and incongruence of the acetabular roof.	OA appeared after five years of follow-up in between 13% to 57% of all cases. OA was present in approximately 36% of cases after open reduction and internal fixation.
Femoral Fractures	Femoral neck: 63.3 cases per 100,000 person-years for women and 27.7 cases per 100,000 person-years for men (90 percent of proximal femur fractures) Intertrochanteric: 34 men and 63 women/ 100,000 person years. They represents 38%-50% of all hip fractures, respectively.	Patients with a higher falling risk. Higher incidence of stress fractures in military. Female sex older age osteopenia or osteoporosis.	OA risk seems higher in trochanteric fractures than in patients with cervical fractures. Femoral shaft malunions increase the risk of OA symptoms, pain and stiffness after long-term follow up (>20years). In young patients, use of a hemiarthroplasty after femoral fractures has been linked to OA at follow up.	PTOA in 0.5% of cases with minimally displaced femoral neck fracture treated with internal fixation. After femoral shaft fractures and malunion, 8% of cases had radiographic evidence of OA. PTOA in 31% of cases after a failed internal fixation for hip fracture with a minimum 2-year follow-up. Around 11% of all performed THA are sequelae or failed internal fixation after proximal femur fracture.
Hip dislocations	Most are posterior dislocations (90%). Classified as simple or complex (when associated with fractures). Acetabular fracture is present in up to 70% of patients with traumatic hip dislocations.	More prevalent in males between 14 or 16 years to 40.	Delayed closed dislocation reduction (>six hours of the injury). The severity of the injury correlates with an increase in the development of PTOA. Associated with femoral head fracture increase the risk of OA.	PTOA is the most common sequelae. Might appear just two years after the initial injury, being more common after ten years. It might be present in up to 24% of cases. PTOA in between 16-30% of patients with posterior dislocation and 50% when associated with femoral head fracture.