Injury
Sciatic nerve injury occurs between 0.5% and 2.0% of the time during a hip replacement. Sciatic nerve palsy is a complication of total hip arthroplasty with an incidence of 0.2% to 2.8% of the time, or with an incidence of 1.7% to 7.6% following revision. Following the procedure, in rare cases, a screw, broken piece of trochanteric wire, fragment of methyl methacrylate bone cement, or of a Burch-Schneider antiprofusio cage can impinge on the nerve; this can cause sciatic nerve palsy which may resolve after the fragment is removed and the nerve freed. The nerve can be surrounded in oxidized regenerated cellulose to prevent further scarring. Sciatic nerve palsy can also result from severe spinal stenosis following the procedure, which can be addressed by spinal decompression surgery. It is unclear if inversion therapy is able to decompress the sacral vertebrae; it may only work on the lumbar aspects of the sciatic nerves. Sciatic nerve injury may also occur from improperly performed injections into the buttock, and may result in sensory loss. : 66

Other disease
Bernese periacetabular osteotomy resulted in major nerve deficits in the sciatic or femoral nerves in 2.1% of 1760 patients, of whom approximately half experienced complete recovery within a mean of 5.5 months.Sciatic nerve exploration can be done by endoscopy in a minimally invasive procedure to assess lesions of the nerve. Endoscopic treatment for sciatic nerve entrapment has been investigated in deep gluteal syndrome.
Post-thrombotic syndrome (PTS), also called postphlebitic syndrome and venous stress disorder is a medical condition that may occur as a long-term complication of deep vein thrombosis (DVT). Signs and symptoms
Signs and symptoms of PTS in the leg may include:
pain (aching or cramping)
heaviness
itching or tingling
swelling (edema)
varicose veins
brownish or reddish skin discoloration
ulcerThese signs and symptoms may vary among patients and over time. With PTS, these symptoms typically are worse after walking or standing for long periods of time and improve with resting or elevating the leg.PTS lowers a persons quality of life after DVT, specifically with regards to physical and psychological symptoms and limitations in daily activities. Cause
Despite outgoing research, the cause of PTS is not entirely clear. Inflammation is thought to play a role as well as damage to the venous valves from the thrombus itself. This valvular incompetence combined with persistent venous obstruction from thrombus increases the pressure in veins and capillaries. Venous hypertension induces a rupture of small superficial veins, subcutaneous hemorrhage and an increase of tissue permeability. That is manifested by pain, swelling, discoloration, and even ulceration. Risk factors
The following factors increase the risk of developing PTS:
age > 65
proximal DVT
a second DVT in same leg as first DVT (recurrent ipsilateral DVT)
persistent DVT symptoms 1  month after DVT diagnosis
obesity
poor quality of anticoagulation control (i.e. dose too low) during the first 3 months of treatment

Diagnosis
When physicians find a DVT in the clinical history of their patients, a postthrombotic syndrome is possible if the patients have suggestive symptoms.