Evidence-based review article grounded in the APTA clinical practice guideline, revised in 2026 (Bove et al.), which replaces the 2020 edition (Jette et al.), retained here for the assessment tests it selected; in the Cochrane Library (cryotherapy, 2025); in the Lancet Rheumatology / Sports Medicine meta-analyses; and in prospective data from 2023-2026 (Steinmetz, Aggarwal, DeFrance, Churchill, Høvik, Rauzi, Adebero).

Total knee arthroplasty (TKA, or TKR in British usage) is a joint replacement procedure that aims to replace the damaged articular surfaces of the knee with prosthetic implants. Its main and almost exclusive indication remains severe knee osteoarthritis (ICD-11 : FA01.0), at the end stage, when conservative treatments (exercise, NSAIDs, weight loss, injections) have failed.² 🦵

How is this procedure defined, who is affected and what are the risk factors?

The global burden of osteoarthritis has been updated by the Global Burden of Disease Study 2021 (Steinmetz et al., Lancet Rheumatology 2023). The figures previously cited (“528 million in 2019”) are replaced by the consolidated estimates: 595 million people were living with osteoarthritis worldwide in 2020, of whom about 365 million had knee involvement. The projection to 2050 anticipates nearly a billion cases globally and an increase of +75 % specific to knee osteoarthritis.¹

The main risk factors, modifiable or not, are:

• Age : prevalence peaks after the age of 60.¹⁴
• Female sex : markedly higher risk after the menopause.¹⁴
• Obesity : a major mechanical and inflammatory risk factor. Relative risk of knee osteoarthritis of 2.45 for overweight and 4.55 for obesity (Zheng & Chen 2015 meta-analysis).³
• History of trauma : the Poulsen 2019 meta-analysis establishes a risk of knee osteoarthritis multiplied by 4 to 6 after ligament injury (ACL) or articular fracture.⁴
• Preoperative psychological factors : the Lewis 2015 meta-analysis (BJA) identifies depression, anxiety, catastrophising and low self-efficacy as independent predictors of persistent pain after TKA.⁵

What happens in the body, and how does recovery progress naturally?

TKA is a major tissue insult that triggers a local inflammatory response, with oedema and acute pain.⁶ The most universal consequence is marked, persistent weakness of the ipsilateral quadriceps.

This weakness is not only due to atrophy. It is made worse by arthrogenic muscle inhibition (AMI), a neurological reflex mechanism: nociceptive and joint-distension signals actively inhibit recruitment of the quadriceps motor neurones.⁷ The narrative review by Churchill et al. 2023 (Osteoarthritis Cartilage Open) updates the data: the loss of quadriceps strength reaches up to −62 % in the first month after surgery, and the activation deficit outweighs pure atrophy.⁸ This figure corrects the historically cited “−80 %”.

The most significant improvement occurs during the first 3 to 6 months, with progress possible up to 12 to 24 months. High pain intensity in the first week is strongly correlated with poorer outcomes at 6 and 12 months.¹¹ The use of early mobilisation within 24 h reduces the mean length of stay by 1.8 days (95 % CI 1.1-2.6) according to the meta-analysis by Guerra et al. (2015, Clinical Rehabilitation, 5 RCTs, n=622) and prevents thromboembolic complications.¹⁵

How do you assess and diagnose the post-TKA patient with certainty?

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Assessment after TKA is biopsychosocial. It goes beyond measuring range of motion and strength to take in expectations, psychological profile and the expected functional trajectory. A structured, evidence-based approach is essential to identify the factors of success, anticipate complications and personalise management. 🧐

Which questions should you ask to understand the patient and their history?

History-taking is the cornerstone of assessment. It explores four key areas:

• Preoperative expectations and satisfaction : unrealistic expectations are strongly correlated with postoperative dissatisfaction, even when objective results are good.¹ A structured discussion of how well expectations match current results is essential.
• Psychological and social profile : depression, anxiety, catastrophising and kinesiophobia predict persistent pain and functional limitation.³ The 10-year follow-up by Goh et al. (2020, Bone Joint J) confirms the lasting impact of preoperative psychological distress.¹⁴
• Characterising the pain : location, type, intensity (VAS), aggravating factors. Night pain, fever or persistent discharge should raise suspicion of periprosthetic infection.⁵
• Comorbidities and referred pain : diabetes, cardiovascular disease, obesity, but also hip pathology or lumbar spine conditions that can refer pain to the knee (Dibra 2018).⁶

Which clinical tests should you perform, and which conditions must be ruled out?

The clinical examination combines objective measures, standardised functional tests and a process of differential diagnosis. 🩺

Physical examination and recommended functional tests

Beyond range of motion (full extension, flexion gain ≥ 110-120°) and quadriceps strength, the clinician should use standardised functional tests; the APTA 2020 Clinical Practice Guideline (Jette et al., Physical Therapy) selects, by working group consensus, the TUG and the 30STS, together with the KOOS JR:⁷

These objective tests are complemented by validated patient-reported outcome questionnaires (PROMs), namely KOOS (Knee injury and Osteoarthritis Outcome Score) or OKS (Oxford Knee Score), which quantify the patient's perception of pain, function and quality of life.⁸

Differential diagnosis: red flags in the post-TKA consultation

The systematic review by DeFrance & Scuderi 2023 challenges the historical figure of 20 % dissatisfaction: the real value is closer to 10 % on average (7.3 % excluding complications).¹ Faced with a plateau or atypical pain, however, the physiotherapist must set a rigorous differential diagnostic process in motion:

Should patients with pain after TKA be classified, and what are the benefits?

The “one size fits all” approach is outdated. Recent literature promotes stratified rehabilitation based on homogeneous subgroups. The prospective study by Golinelli 2023 (BMC Musculoskelet Disord) identified several distinct PROM recovery trajectories (three per questionnaire) after elective TKA.¹²

The randomised controlled trial by Bade & Stevens-Lapsley 2017 (Arthritis Care Res) remains the most robust study on stratification by intensity: 162 patients compared according to psychological profile (kinesiophobia) and quadriceps strength deficit. Progressive high intensity demonstrated its safety, with no excess of adverse events versus standard intensity.¹³

The benefits of such a classification:

1. Personalisation : tailoring interventions to specific barriers (kinesiophobia → education and graded exposure).
2. Optimised allocation : intensifying management for slow trajectories.
3. Better outcomes : targeting individual obstacles improves satisfaction.

The APTA clinical practice guideline, revised in 2026 (Bove et al., Physical Therapy, literature search closed on 2 January 2025), replaces the 2020 edition (Jette et al.).¹⁴ It sets out a hierarchy of interventions dominated by early, structured, progressive therapeutic exercise. On cryotherapy, it does not say the same thing as the 2025 Cochrane review (box below). 💪

Where do you start? What is the recommended hierarchy of interventions?

What the APTA guideline (2026 revision) recommends first, with its quality of evidence and strength:

1. Early physiotherapy and mobilisation (within 24 h) : moderate evidence, moderate strength; the Guerra 2015 meta-analysis (5 RCTs) finds a hospital stay about 1.8 days shorter, with no increase in complications.^2,14
2. Prehabilitation (exercise + education 6-8 weeks before surgery): the guideline calls for designing a preoperative exercise programme (high quality of evidence according to the APTA, moderate strength, small to moderate effects, mainly in the first six weeks after the operation); the meta-analysis by Adebero 2024 reports a benefit on function, pain and strength after TKA, with a high risk of bias in 24 of the 28 trials, which limits its scope.^7,14
3. Progressive strengthening from the early post-acute phase: high evidence, strong recommendation in 2026 (the 2020 edition rated high-intensity strengthening as a moderate-strength recommendation).^1,14
4. Structured therapeutic education (managing expectations, pain neuroscience, self-management): no recommendation of its own in the 2026 revision, which mentions it within the preoperative programme.^12,14
5. Motor training (dynamic balance, gait retraining, movement work with feedback): high evidence, strong recommendation, in 2020 as in 2026.^1,14

What is the place of exercise, and is there a superior approach?

Progressive strength training is, together with motor training, one of the strong recommendations of the APTA guideline, based on high-quality evidence (2026 revision).¹⁴ A central question concerns the optimal intensity. The landmark randomised controlled trial by Bade & Stevens-Lapsley 2017 compares high vs low intensity in 162 patients over 11 weeks: at 12 months, both groups significantly improve on functional tests (6MWT, TUG, quadriceps strength), with no clear superiority of high intensity and with no excess of adverse events.⁴ High intensity is therefore safe but should not be applied dogmatically.

Motor training (dynamic balance, gait retraining, movement work with feedback) is not a mere add-on to strengthening: the APTA guideline has made it a strong recommendation since 2020, renewed in 2026.^1,14 A synergistic combination of strength + neuromuscular + functional work gives the best results.⁵

Manual therapies and technologies: how effective are they really?

The use of manual therapy (patellar and tibiofemoral mobilisation) provides short-term benefits on range of motion and pain, especially in the early phase, to make it easier to take part in exercise.¹⁰ The Yang 2025 meta-analysis (Appl Sci) confirms its value as a complement to exercise, never as an alternative.

The neuromuscular electrical stimulation (NMES) of the quadriceps has been recommended by the APTA guideline since 2020. The 2026 revision (moderate evidence, moderate strength) specifies the dose: at least once a day, from the early postoperative phase, at the highest tolerated intensity, for at least three weeks, for quadriceps strength, walking and performance tests. It mainly benefits patients whose quadriceps activates poorly (active extension lag), is decided with the patient, and is not used in the presence of a demand pacemaker, active cancer or deep vein thrombosis.¹⁴ The meta-analysis by Peng et al. 2021 (Frontiers in Medicine, 9 RCTs, 691 patients) confirms its effectiveness on strength, pain and function in the short and medium term after TKA.⁸

The telerehabilitation approach has become a credible alternative: the meta-analysis by Tsang 2024 (J Telemed Telecare) of 11 studies (n=1825) shows functional outcomes that are non-inferior to on-site rehabilitation for selected patients.⁹

The use of Blood Flow Restriction Training (BFR) is emerging as a promising strategy: the systematic review by Tiss 2025 (Medicina) includes 4 RCTs and 148 TKA patients: a probable benefit on postoperative muscle loss, but methodological heterogeneity still limits definitive conclusions.¹¹ Our review of BFR in physiotherapy details the settings, the indications and the screening.

Beyond the physical: how do you educate the patient and address psychological factors?

Rehabilitation rarely fails because of a poor exercise protocol. Psychosocial factors dominate the long-term predictors. 🧠 The systematic review by Burns 2015 (J Pain Res) identifies pain catastrophising as one of the most powerful predictors of chronic pain after TKA.¹³

Therapeutic education must go beyond simply explaining the exercises and include:

• The management of expectations (realistic outcomes, non-linear pace of recovery).
• Strategies for self-management (pain, inflammation, pacing, sleep).
• An approach of collaborative goal-setting aligned with the patient's values and meaningful activities.
• An approach based on Pain Neuroscience Education (Louw 2019) in cases of marked catastrophising or kinesiophobia.¹²

The success of a TKA is judged over the long term: independence, return to meaningful activities, lasting quality of life. Two pillars structure this phase: self-management and the planning of a safe return to physical activity. 🧘

How do you make the patient an active participant in their recovery through self-management?

Self-management is a key determinant of long-term outcomes. Three concrete levers validated by the 2023-2026 literature:

• Structured therapeutic education (pre-op + post-op): improves self-efficacy and reduces anxiety. The direct impact on physical function in the very long term is still debated.¹
• Telerehabilitation and digital tools : the meta-analysis by Tsang 2024 confirms non-inferiority versus on-site care for pain and function. Mobile apps and wearable sensors improve treatment adherence.²
• Patient-initiated follow-up : a safe and effective approach that lets the patient request a consultation when needed.⁹

When and how should a safe return to sport and activities be planned?

Current data are encouraging, but the figures vary. The meta-analysis by Pasqualini et al. 2023 (JBJS Reviews, 44 studies) puts the rate of return to a sporting activity after TKA at 82 % (95 % CI 72 to 89 %), ranging from 36 to 100 % depending on the study, with a mean time to return of 20 weeks.¹⁰ The prospective cohort by Soares et al. 2026 (1,464 sports participants followed for one year) finds 53.4 % returning at one year, with a median time of 12 weeks.¹¹ The earlier meta-analysis by Witjes 2016 (18 studies) gave a return rate of 36 to 89 % after TKA.⁵ It is better to give a range than a single figure.

Planning the return rests on the distinction between low / high intensity :

• Low intensity (cycling, swimming, golf, for example): 76 % return rate (95 % CI 59 to 87 %), ranging from 43 to 98 % depending on the study.¹⁰
• High intensity (running, tennis, basketball, contact sports): 35 % return rate (95 % CI 20 to 52 %), ranging from 0 to 55 % depending on the study.¹⁰ Most surgical recommendations advise caution for fear of premature polyethylene wear, aseptic loosening or periprosthetic fracture.⁸

The predictive factors for a successful return to sport are: younger age, male sex and, above all, a high preoperative activity level (Bonnin 2010).⁶ The final decision must come from a shared decision between patient, physiotherapist and surgeon.

Case 1: fast-track recovery after primary TKA (Bade & Stevens-Lapsley 2017)

The landmark RCT by Bade and Stevens-Lapsley (2017, Arthritis Care Res) compared a protocol of progressive high intensity (resistance exercise, rapid weight-bearing) with standard intensity in 162 TKA patients (89 women, mean age 63 ± 7 years).¹ Both protocols were delivered 2-3 times a week for 11 weeks (26 sessions).

Results at 12 months : both groups significantly improved on the functional tests (6MWT, TUG, quadriceps strength, WOMAC, SF-12), with no clear superiority of the high-intensity group and with no excess of adverse events.

Clinical take-away : high intensity is safe and feasible from the early phase, but the marginal benefit over a well-conducted moderate intensity must be weighed against the subjective burden and the availability of sessions. Individualisation remains the key.

Case 2: arthrofibrosis after TKA, a multimodal programme vs manipulation under anaesthesia (Rauzi 2022)

Arthrofibrosis is a feared complication (severe restriction of ROM, functional stiffness) that occurs in around 1-4 % of patients after primary TKA.³ The feasibility study by Rauzi et al. (2022, Pilot Feasibility Stud) compared a conservative multimodal programme, delivered prospectively, (manual therapy + therapeutic exercise + static progressive splinting for 4 weeks) with a retrospective cohort treated by manipulation under anaesthesia (MUA); the multimodal group comprised 10 patients with early arthrofibrosis at 6 weeks after TKA.²

Final ROM results : 110° ± 14 (multimodal) vs 109° ± 11 (MUA). Of the 10 patients in the multimodal group, 7 achieved a functional ROM ≥ 110° and avoided MUA.

Clinical take-away : faced with early arthrofibrosis (6 weeks post-op), an intensive conservative multimodal programme can avoid an intervention under anaesthesia in 70 % of cases. The early therapeutic window (4-6 weeks) is crucial. This programme targets established arthrofibrosis: the 2026 revision of the APTA guideline advises against routine splinting after uncomplicated primary TKA, and refers severe stiffness and arthrofibrosis to individualised management.⁷

Case 3: common fibular nerve palsy after TKA (Høvik 2024)

Common fibular nerve palsy (CPNP) is a rare but disabling complication. The registry cohort study by Høvik et al. (2024, Arthroplasty Today) reports an incidence of 0.32 % in a 2002-2022 cohort, with excessive preoperative valgus multiplying the risk (adjusted OR 9.6, 95 % CI 2.5-48.1).⁴ The risk factors are epidural anaesthesia, excessive valgus and female sex.

Multimodal management combines:

• Ankle-foot orthosis to make walking safe straight away.
• Strengthening of the preserved muscles (tibialis posterior, toe flexors).
• Functional electrical stimulation (FES) to assist dorsiflexion during walking.
• Gait retraining towards safe walking, and balance work.

Clinical take-away : most patients recover partially or completely; partial palsies have a better prognosis than complete ones. The multimodal approach improves independence even without complete neurological recovery.

Applying clinical recommendations is the bridge between science and care. It requires an understanding of the evidence, but also a pragmatic strategy for referring patients, measuring outcomes and removing systemic and individual barriers. 🧭

When, and to which other health professionals, should you refer?

The direct-access physiotherapist must know how to triage and refer effectively using a system of clinical flags.

Urgent medical referral: red flags

The International Framework for Red Flags by Finucane et al. (2020, JOSPT) stresses that the predictive value of an isolated red flag is low.² Cook et al. (2018, BJSM) specify that assessment must take place within the patient's overall context, not through a simple checklist.³ After TKA, the signs that call for immediate referral to the GP or the surgeon are listed in the red flag box in chapter 2.

Mental health referral: yellow flags

Cognitive-behavioural factors (kinesiophobia, mistaken beliefs, catastrophising) may justify working with a psychologist specialising in cognitive behavioural therapy (CBT). Approaches based on Pain Neuroscience Education (Louw 2019) have shown preoperative effectiveness on post-TKA pain.⁴

Interprofessional referral

• Orthopaedic surgeon : prolonged plateau, suspected mechanical problem, indications for revision.
• Rheumatologist : suspected underlying systemic inflammatory disease.
• Neurologist / EMG : postoperative peripheral neurological deficit (fibular, femoral, saphenous).
• Pain medicine physician : uncontrolled chronic pain, suspected CRPS.
• Psychologist or CBT-trained physiotherapist : catastrophising, marked kinesiophobia.

How do you measure outcomes and overcome barriers to implementation?

Measuring what matters to the patient

Systematic use of validated PROMs (KOOS, OKS, Oxford-12, EQ-5D) makes it possible to quantify progress and facilitates shared decision-making by aligning goals with the patient's expectations. The founding reference by Hoffmann, Montori and Del Mar (2014, JAMA) remains the theoretical basis for the link between EBP and shared decision-making.⁵

Pyramid of levels of evidence applied to post-TKA rehabilitation

Summary: modality × level of evidence × optimal timing

Overcoming the barriers to EBP

The classic barriers (lack of time, lack of critical appraisal skills, limited resources, organisational culture) can be overcome with multifaceted strategies :

• Targeted continuing education (critical appraisal, keeping CPGs up to date).
• Clinical leadership and mentoring (“EBP champions”).
• Integration of digital tools (CPG reminders, automated PROMs, telerehabilitation).
• Audit and feedback : according to the Cochrane review (Ivers 2026, 292 randomised studies), a mean absolute increase of 6.2 % in the desired practice (95 % CI 4.1 to 8.2; moderate certainty), with highly variable effects; the effect appears larger with individual data, a comparison with the best-performing peers or with a benchmark, a local lead known to the recipient, and an action plan. The recipients were mostly doctors.⁶