Postoperative Complications of Total Hip and Total Knee Arthroplasty

1. Postoperative Complications of Total Hip and Total Knee Arthroplasty Presented by Spencer F. Schuenman, D.O.

2. Postoperative Complications of Total Hip Arthroplasty • Wound Infection • Dislocation • Ectopic Bone • Thromboembolic Disease • Nerve Palsies, Limb Length Inequality, Osteolysis

3. Postoperative Deep Wound Infection • “Late infection is difficult to diagnose during the first hospitalization, particularly when prophylactic antibiotics have been administered. Late infection is the most serious complication which can follow total prosthetic replacement and is a catastrophe for both surgeon and patient...” M. E. Mueller, 1970

4. Incidence • Initial experience • Sir John Charnley experienced initially deep sepsis with THA in 8.9 percent of cases. • Wilson 11.0 percent • Patterson 8.0 percent • Mueller 4.0 percent • Current experience • Charnley 0.61 percent • Lidwell 1.3 percent • Fitzgerald 0.51 percent • Schutzer 0.38 percent • Salvati 1.4 percent • Factors thought to influence wound infection • presence or absence of unidirectional airflow • perioperative antibiotic use • use of major bone grafting • development of post op hematomas • previous hip operations • prolonged OR times

5. Diagnosis • Laboratory Assessment • Diagnosis rests on the isolation of the microorganism(s) from several clinical tissue specimens from about the hip. • *A high suspicion should be present in patients with persistent pain. • 54 % had an elevated ESR> 30mm/hr • 44 % had a fever • 15% had leukocytosis • All had pain in their infected hip • Radiographic clues • progressive radiolucency at the bone-cement interface or endosteal scalloping • Periosteal new bone formation surrounding a prosthesis is pathognomonic • Arthrography-true value is that aerobic and anaerobic cultures can be obtained by aspiration. • Indium-labeled-leukocyte technique-if negative highly unlikely sepsis is present.

6. Clinical Features-Three Stages • Stage I-symptoms appear within first three months • Febrile course often observed • Usually an infected hematoma beneath fascia • Spontaneous drainage is common • Some progress from an initial superficial infection • Stage II-six to 24 months • Absence of pain-free interval after surgery • creeping, indolent progression • febrile course unusual • Stage III-beyond 24 months • Long asymptomatic interval after arthroplasty • acute onset of pain beyond 24 months • febrile illness common at onset of delayed symptoms • distant focus of infection often difficult to ascertain

7. Microbiology • Predominantly Staphylococcus epidermidis and aureus • Streptococcus viridans • Group-D Streptococcus • E. Coli • Low virulence organisms 70% • Virulent organisms 25%

8. Treatment • Acute infection-debridement and 4 weeks of parental therapy can occasionally be effective • Mainstay of therapy-resection arthroplasty with a one, two, or three stage reconstructive procedure. • Low virulent organism-reconstruction can be performed as early as three months after resection and antibiotics • High virulence-12 months or more

9. Postoperative Dislocation • Second in frequency to loosening as causes of instability post op • It may necessitate prolonged hospitalization, rehabilitation, and functional impairment

10. Incidence • The literature reports a wide range of incidence figures for this problem. • Review of 16 reports from 1973 through 1987 of over 35,000 procedures, there were just over 800 dislocations for a rate of 2.23%.

11. Mechanism • There are two mechanisms that are well recognized by the clinician to place the hip at risk • 1. Flexion, adduction, and internal rotation-results in posterior dislocation • 2. Less common-extension, adduction, external rotation-results in anterior dislocation and is most frequently seen after an anterior approach and when excessive anteversion in imparted.

12. Risk Factors • Preoperative Factors • Age and Sex-mean age who dislocate was 64 yo. • Height and Weight-only speculative conclusions at present • Bilateral Procedures-no difference was found • Underlying Diagnosis-no correlation with preop Dx and postop dislocation. Even congenital hips does not show a definite correlation to instability. • Prior Surgery-this plays a significant role in subsequent hip instability. • Perioperative Factors • Surgical approach-the posterior approach is statistically at a greater risk for instability than the anterior approach. • Aftercare-No effect in postop management was noted to increase instability. • Component Head Size-no correlation can be found between head size and prosthetic instability. • Range of Motion-hips with increased ROM have a greater tendency for instability due to the levering action of the femoral neck on the acetabulum. • Limb Length Inequality-literature suggests a possible but relatively minor correlation between leg length and instability. • Component Orientation-some consider acetabular orientation to be the most sensitive variable in predisposing to hip dislocation. Excessive femoral anteversion can also be a predisposing factor. • Trochanter-trochanteric osteotomies can lead to nonunion which increases instability.

13. Treatment • Nonoperative Treatment-successful in two-thirds of patients. • Operative Treatment-only 1 in 100 patients who underwent THA will come to revision surgery directed at instability • posterior dislocation is most common so an enhanced posterior wall of the acetabulum should increase stability. • trochanteric advancement • cross flap capsuloplasty

14. Ectopic Bone Formation • Classification Systems • Class I: Islands of bon within the soft tissues about the hip. • Class II: Bone spurs from the pelvis or proximal end of the femur, leaving at least 1 cm between opposing bone surfaces. • Class III: Bone spurs from the pelvis or proximal end of the femur, reducing the space between opposing bone surfaces to less than 1 cm. • Class IV: Apparent ankylosis of the hip.

15. Incidence and Predisposing Factors • Varies between 20 and 80%, but only significant in 5 to 10% of hips. • History of ankylosing spondylitis • Men with hypertrophic osteoarthritis • Previously developed ectopic bone secondary to previous surgeries

16. Prevention of Ectopic Bone • Surgical prevention • Good surgical technique • remove all bone dust and debris • minimize trauma to the abductor and adductor groups • reduce incidence of hematoma formation by adequate drainage • contain bone graft material so that it won’t migrate into the soft tissues • postoperative prevention • Irradiation-low dose • use of diphosphonates • NSAIDS

17. Thromboembolic Disease • The primary goal of DVT prophylaxis is the prevention of PE

18. Pathogenesis • Described by Virchow over 100 years ago, known as Virchow’s triad: • 1. enhanced blood coagulation • 2. vessel wall injury • 3. altered blood flow

19. Diagnosis • Reliance on clinical symptoms is well known to be inaccurate for the diagnosis of either DVT or PE. • Venography-remains the gold standard for Dx of DVT • It is invasive, expensive, and associated with complications • Doppler-highly variable because of the subjective nature of its interpretation. Limited in diagnosing DVTs in the calf. • safe, rapid, simple, and inexpensive • 125I Fibrinogen-sensitive for calf DVT, but missed proximal DVTs due to labeled fibrinogen in the wound area. • Compression Duplex Ultrasonography-very specific for proximal DVTs, but insensitive for smaller DVTs. Also interpreter dependent. • Impedance Plethysmography-uses the electrolyte-rich blood to measure conduction. Highly sensitive and specific in clinically suspected DVT of the proximal thigh but less so with isolated calf DVTs.

20. Prophylaxis • The primary goal is to prevent fatal pulmonary embolism.

21. Methods of Prophylaxis • Nonpharmacologic • Early Ambulation and Graduated Compression Stockings • Intermittent Sequential Pneumatic Compression • Type of Anesthesia-spinal is associated with significantly fewer postoperative DVT than with general or epidural. • Pharmacologic • Heparin (minidose)-no prolongation of APTT. • Low-Molecular-Weight Heparin-inhibits factor X, does not inhibit platelet aggregation. • Warfarin- inhibits factors II, VII, IX, X and proteins C and S • Adjust to 1.25-1.50 times normal by the third postop day • increased bleeding complications with PT >1.5 times • Aspirin-inhibits platelet aggregation

22. Other Postop Complications • Nerve Palsies-due to revision surgery, limb lengthening, anticoagulation postop, vascular insufficiency, women > men. • Prevention-avoid lengthening > 4cm, careful monitoring of anticoagulation, good technique. • Limb Length Inequality-more important to establish stability than to overcome a leg length discrepancy. • Osteolysis-a process of softening, absorption, and destruction of bony tissue demonstrated on x-ray by a progressive radiolucent line or cavity at the bone-cement or bone-implant interface • MUST RULE OUT INFECTION!