Postoperative Complications of Total Knee Arthroplasty

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Postoperative Complications of Total Knee
Arthroplasty

• Presented by Spencer F. Schuenman, D.O.

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Complications of TKA

• Infection
• Medical Complications
• cardiovascular disease
• diabetes mellitus
• renal disease
• pulmonary disease

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• Surgical Complications
• incorrect alignment
• ligamentous laxity
• flexion contractures
• extensor mechanism problems
• Wound Healing
• Neurovascular complications

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• Thromboembolism
• Fat Embolization
• Fracture
• Device Failure

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Infection

• Incidence-has been reported to be less than 1
  with resurfacing arthroplasty and as high as 16
  with hinged implants

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• Etiology-the host response is influenced by such
  factors as rheumatoid arthritis, diabetes
  mellitus, poor nutrition, extreme old age, and
  obesity.

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• The size, design, and type of fixation of the
  prosthesis may also influence the incidence of
  sepsis.
• A hinged metal-on-metal prosthesis has an
  infection rate as much as 20 X higher than
  metal-on-plastic.
• Monomeric methyl methacrylate has been shown to
  impair leukocyte chemotaxis and phagocytosis

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• Surgical Technique and Environment
• Hemostasis, shorter operating time, use of
  previous surgical incisions, decreased traffic in
  the OR, will help minimize postoperative sepsis.

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• Diagnosis-this is similar to that of diagnosing
  infection in THA.
• Pain, prolonged drainage, decreased ROM, temp.
  elevation may all be present with sepsis.
• Arthrocentesis, bone scan, and the indium labeled
  scan are all used in detecting sepsis.

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• Microorganisms-Staphylococcus, Streptococcus, E.
  Coli, Pseudomonas, and anaerobes make up the
  majority of pathogens.

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• Treatment-Aggressive debridement, removal of
  hardware, and parental antibiotics remain the
  mainstay of treatment.
• Reimplantation can be performed if consecutive
  negative cultures are present. If sepsis cannot
  be controlled, an arthrodesis is then performed.

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Medical Complications

• Medical complications are much more common than
  surgical complications. It is necessary to work
  with a skilled internist during perioperative
  management and to take great care on positioning
  the patient during the procedure and
  postoperatively.

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Surgical Complications

• Good surgical technique and the use of proven
  components help in preventing complications of
  incorrect alignment, ligamentous laxity, flexion
  contractures, and extensor mechanism problems.

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Wound Healing

• Clinical factors that adversely affect wound
  healing obesity, rheumatoid arthritis, diabetes
  mellitus, and tobacco smoking.

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• Choice of surgical incision is important
  preexisting incisions should be utilized whenever
  possible to prevent skin necrosis between the old
  and new incision.
• Wound drainage should be treated aggressively.

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Neurovascular Complications

• This complication occurs infrequently in TKA.
  Local cutaneous nerves, especially laterally
  often result in decreased sensation.

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• The major neurological complication with TKA is
  peroneal nerve palsy. This occurs in less than
  1 of cases.
• Treatment includes flexion of knee, removal of
  any tight dressings over the nerve, and by use of
  an ankle-foot orthosis, if a significant deficit
  is noted.
• A sensory deficit has a better prognosis than a
  combined sensory-motor deficit.

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• Arterial vascular injury is very infrequent with
  an incidence of about 0.03. The most common
  etiology is use of the tourniquet over an
  atherosclerotic vessel which causes subsequent
  embolization.

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• Postoperative pain out of proportion which is
  unresponsive to narcotic therapy should raise
  concern for arterial compromise. Immediate
  arteriography and vascular surgical consultation
  should be obtained.

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Thromboembolism

• Prospective studies have shown an incidence of
  thrombosis of 50 to 70. Location is primarily
  in the calf veins, but the popliteal and femoral
  veins are involved in 5 to 10.

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• Bilateral TKA has shown an incidence of increased
  thromboembolism.
• A recent survey at the Mayo Clinic comparing TKA
  and THA revealed more instances of pulmonary
  emboli after TKA than THA.

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• Prophylaxis includes early motion of the knee,
  antiembolism stockings, SCDs, Warfarin, and
  low-molecular-weight heparin.

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Fat Embolization

• Primarily seen with use of long-stemmed implants
  or intramedullary instrumentation for limb
  alignment.
• This is a very infrequent complication in TKA.

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Fracture

• Periprosthetic fractures post TKA are also very
  infrequent
• The etiology of these fractures is osteoporosis,
  notching of the anterior femoral cortex, and
  trauma.

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Device Failure

• Implant breakage and failure was initially
  related to specific designs.
• Of greater concern at present is failure of the
  polyethylene as a bearing surface. The
  polyethylene thickness should be a minimum of 8mm
  to avoid problems with polyethylene failure.

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Summary

• A thorough preoperative evaluation and
  consultation with appropriate specialists will
  avoid many postoperative medical complications.
  Careful surgical technique will avoid many
  postoperative surgical complications.

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• Aggressive management of postoperative
  complications is essential to prevent further
  difficulties such as postoperative wound sepsis.
  The goal of wound healing must take priority over
  achieving postoperative knee motion. Correct
  limb alignment must be obtained to maintain an
  appropriately functioning arthroplasty.