Surgical options - Total knee replacement

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Rate: in 2016 was 242 per 100,000 of population, with 70% in private sector (Jt replacement registry)

Estimated to rise 276% by 2030, and cost to healthcare system of $5.32 billion (Ackerman et al., 2019)

Outcomes:
-up to 24% of patients experience serious adverse event (Skou et al., 2015)
-approx 20% of patients experience ongoing pain and dissatisfaction (Beswick et al., 2015; Gunaratne et al., 2017)

More severe radiographic changes are most likely to have substantial gains in pain relief and improved function as a result of TKR (Dowsey et al., 2012)

How long do hip and knee replacements last?

-Hip: 10 year implant survival rate 95.6%, 20 year survival rate 85% (Bayliss et al, 2017), 25 years survival rate 58% (Evans, Evans, et al., 2019)

-Knee: 10 year implant survival rate 96.1%, 20 year survival rate 89.7% (Bayliss et al 2017), 25 years survival rate 82%, UKR 25 year survival rate 70% (Evans, Walker, et al., 2019)

-if aged btn 50-55 years and male, higher revision rate (1 in 3) but also shorter time to revision

-if older than 60 at primary replacement, risk of revision decreases, and by age 70 is less than 1 in 20

Summary:

According to Adie et al (2019), the minimum requirement for a TKR are:

• Intractable pain affecting quality of life
• Severity of pain suggests potential benefits of surgery outweigh the risks
• Radiographically evident knee osteoarthritis (KL Grade 3 or 4)
• Other signs including stiffness, instability and deformity to which symptoms can be attributed

The NICE guidelines (National Institute for Health and Care Excellence, 2014) also suggested that symptoms should be prolonged and established to avoid operating on people with transient symptoms or acute flare ups. The current consensus is to trial non-operative treatment for 3-6 months prior to considering a TKR.

Also recommended to consider impact of symptoms on social factors e.g. income generation, carer responsibilities

Victorian MOC suggests:

A poor response to an adequate period of appropriate non-surgical therapy.
2. Radiographic evidence of advanced disease that correlates with symptoms.
3. Objective measures of pain and function that indicate significant impact.
4. The patient is willing to consider major orthopaedic surgery and undergo an
extensive period of rehabilitation.

German study of expert and patient representatives’ consensus on indication for surgery:(Schmitt et al., 2017)

-Knee pain taking into account severity, duration of at least 3-6 months, there at least several times per week
-Proof of structural damage on x-ray
-failure of conservative treatment at least 3-6 months -insufficient response to combination of drug and non-drug conservative therapy
-Impairment of QOL at least 3-6 months
-Knee joint related subjective suffering.

Consider-restrictions in walking distance, long standing or climbing stairs; malalignment of leg axes, instability of knee jt, impairment of ROM, impairment of leg strength, difficulties in sitting down, kneeling down or personal hygiene, necessary support from another person, difficulties in managing household, difficulties in using transport, restrictions in social life, work or sporting activities, avoiding secondary diseases

Relative CI to TKR :(Schmitt et al., 2017)
-significantly shortened life expectancy due to comorbidities
-BMI>40

Absolute CI  (also (Adie et al., 2019)
-infection of knee joint
-systemic infection
-acute CV event

Possible predictors of potential poor outcome

Systematic review (Lewis et al., 2014) found: catastrophising, mental health issues (depression and anxiety), high preoperative knee pain, poorer levels of pre-operative function and pain at other sites are strongest predictors of persistent pain after TKA

-increased risk of complications with chronic diseases such as diabetes, hepatitis C, congestive heart failure, COPD, chronic kidney disease, coagulopathies and cirrhosis (McGrory et al., 2016; Edwards et al., 2018)

-modifiable risk factors-CVD, morbid obesity, malnutrition, poorly controlled diabetes, opioid use, smoking, poor dentition, pre-operative anemia, staphylococcus aureus colonization, physical deconditioning, and neurocognitive, psychological and behavioural problems: implicated in longer length of stay, increased complications, higher rates of early revisions and increased readmissions (Edwards et al., 2018)

Also: -Obese patients have less improvement in outcomes with TKA (strong evidence)(McGrory et al., 2016)

-Patients with select chronic pain conditions have less improvement in patient-reported outcomes (PROs) (moderate evidence)(McGrory et al., 2016)

-patients with depression/anxiety have less improvement in PROs (limited evidence)(McGrory et al., 2016)

-age-younger patients’ higher likelihood of requiring revision, and some evidence clinical results may also be inferior

Click on each of the info button below to learn more about the different co-morbidities and how it relates to TKR:

Obesity

The majority of obese patients don’t lose weight after surgery, and some put on weight; (Dowsey et al., 2010; Heisel et al., 2005)

Smaller improvements and increased rate of adverse events, higher re-admission rate and higher prosthetic infection and revision rate, higher DVT rate with TKR (Dowsey et al., 2010; Kerkhoffs et al., 2012)

American association of hip and knee surgeons workgroup-recommends discussing with all patients with BMI >30kg/m2 are at increased risk of perioperative complications; and recommends consider delaying surgery in patients with BMI >40kg/m2, especially when associated with other comorbidities

Method of weight loss?
Remains uncertain-rapid review with 2 large cohort studies found high rate of all-cause readmission for TKA patients who underwent diet-based pre-operative wt loss, however other studies have found no difference in complications (Liljensøe et al., 2019). Do need to consider dosage of medication if have relatively rapid weight loss-do in conjunction with GP, and Very Low Calorie Diets (e.g. Healthy Weight for Life)  not recommended in patients with acute cerebrovascular or cardiovascular disease (including unstable angina), kidney disease, liver disease, type 1 diabetes or severe psychological disturbances.

Pre operative bariatric surgery?
Systematic review and meta-analysis of bariatric surgery and complications post TJA found no significant differences in peri-operative and post-operative complications. Insufficient data to analyse clinical and functional outcomes, and lack of data as to cost effectiveness and timing of bariatric surgery. (Smith et al., 2016)

How much to try and lose?
Losing at least 9kg prior to surgery if morbidly obese was associated with shorter length of stay and lower odds of facility discharge, no difference if lost 2.25kg or 4.5 kg (Keeney et al., 2019)

Respiratory disease
Sleep apnoea associated with higher risk of aspiration pneumonia; and requirement for intubation/mechanical ventilation post TKA

COPD risk factor for respiratory complications in any surgical patient

Diabetes

Higher risk of deep infection (reduced immune defence mechanisms), impaired wound healing, DVT, aseptic loosening and moderate/severe functional limitations 2 years post TKA

PVD

Higher risk of 90 day mortality and deep infection

Also wound healing problems and risk of ‘catastrophic arterial injury’ after TKA

Smoking

Higher risk of any post operative complication and peri-operative mortality. Previous smokers have similar risk profile to non-smokers, with at least 4 weeks of cessation required to reduce surgical complications

Cardiac disease

Previous MI and heart failure most strongly associated with mortality post TKA

Heart failure and valvular heart disease, particularly aortic stenosis, represent highest risk of peri-operative cardiac mortality-should be referred for specialist assessment

Renal impairment

Have more co-morbidities and a higher risk of superficial wound infection, 90 day readmission and any-time mortality than patients without chronic renal disease  (Miric et al., 2014)