Arthroplasty may be a crucial step to alleviate pain, restore function or correct a developmental or hereditary joint defect. Patient satisfaction and the increase in quality of life are dramatic in the vast majority of cases. However, the procedure is not without its risks.

In many cases, certain factors may rule arthroplasty out as an option. Young age and high activity levels may cause extra stress on a joint or cause a prosthesis (artificial part) to wear out faster, making prosthetic options limited for younger individuals. A nonfunctioning extensor mechanism (which extends the joint) or poor circulation or vascularity may rule out the option of arthroplasty. Prior surgeries in the affected area may also complicate the procedure.

Many conditions can complicate recovery and in some cases may rule out arthroplasty as an option. These conditions include:

• Circulatory and respiratory disorders, such as cardiovascular disease.
  
  
• Blood disorders, such as anemia.
  
  
• Endocrine disorders, such as uncontrolled diabetes and hyperthyroidism.
  
  
• Lipid disorders. Disorders in fat production and metabolism.
  
  
• Urologic disorders, such as benign prostatic hypertrophy (enlargement of the prostate), prostate cancer or urinary tract infection.
  
  
• Infectious diseases.

Arthroplasty carries some risks, though complications are uncommon. They include:

• Thromboembolism. A blood vessel may be blocked by a blood clot dislodged from its site of origin. In particular, deep vein thrombosis is one of the more common serious complications after arthroplasty. Prevention of thromboembolism occurs during and after surgery. Anticoagulants may be used to prevent the formation of blood clots and compression devices and early movement may help to increase circulation.
  
  
• Infection. When infection occurs, the prosthetic devices are removed and the patient is put on several weeks of antibiotics. This is typically unavoidable unless infection occurs in the early postoperative period and is treated aggressively. Infection complications may occur even years after the procedure.
  
  
• Osteolysis. Prosthetic components wear over time, and small particles of debris collect within the joint and surrounding tissues. This causes an inflammatory response that includes enzymes that break down the bone. The frequency of this has decreased with more durable materials and implant designs for prostheses but still represents the largest threat to long-term prosthetic survival. Osteolysis is typically treated surgically.
  
  
• Ossification. Soft tissues around the joint harden. This may be a response to surgical trauma. It is most common in the knee and is usually not painful.
  
  
• Periprosthetic fracture. Fracture that occurs in proximity to a prosthetic implant. Minor fractures may be left alone, whereas surgery may be required to treat larger fractures.

• Prosthetic break. The prosthesis itself may break. Surgery is required to repair it.
  
  
• Aseptic loosening. The prosthesis may become loose. This is more common when bone cement is used to secure it to the bone. Surgery may be required.
  
  
• Dislocation. A prosthetic joint may become dislocated, particularly immediately following surgery when the soft tissues surrounding the joint are weak and still healing. Surgery is usually not required to relocate the joint.
  
  
• Allergic reaction. Many people have allergies to metals but in some cases are unaware of this. This can be a concern with certain prosthetics. Skin patch testing before surgery can avert implantation of a problematic prosthetic.
  
  
• Nerve damage. A number of causes may lead to this, including the compression of a nerve by a prosthesis. Treatment depends upon the cause and may require surgery.
  
  
• Vascular injury. A blood vessel may be injured during surgery. Bleeding must be controlled during the surgery itself.
  
  
• Leg-length discrepancy. Occasionally, one leg may be shorter or longer than the other after a total hip arthroplasty. Surgeons typically take action to avoid this cause of gait disturbance before and during the surgery.