What are common complications to watch for during early rehabilitation after knee replacement?
Executive summary
Early rehabilitation after knee replacement carries several specific risks to monitor: blood clots (DVT) and pulmonary embolism, wound infection (including deep prosthetic infection), stiffness and limited range of motion, prosthesis problems (loosening, malalignment or instability), and complications from immobilization such as pressure ulcers or impaired pulmonary function [1] [2] [3] [4] [5]. Rapid-recovery approaches that emphasize early mobilization can reduce some complications but require protocols and monitoring to be safe [5].
1. Watch for blood clots: the most common early medical risk
Venous thromboembolism — deep vein thrombosis (DVT) with the risk of embolism to the lungs — is repeatedly named as one of the most common early complications after knee arthroplasty and a leading target of preventive measures during rehab; major patient information sources advise vigilance, prophylaxis and early mobilization because clots remain a prominent early threat [1] [6] [4].
2. Wound problems and infection: from superficial redness to deep prosthetic infection
Infection of the surgical wound is a key early concern. Most superficial infections are treated with antibiotics, but deep infection of the joint can require repeat surgery and even replacement of the prosthesis; patients and rehab teams are routinely warned to watch for increasing redness, drainage, fever or worsening pain [7] [2] [1].
3. Stiffness and limited range of motion: a functional complication rehab must prevent
Scar tissue and inadequate motion early on can produce stiffness that impairs long-term outcomes; physiotherapy and prescribed exercises (including walking and knee‑motion work) are central to preventing loss of range, and programs emphasize both supervised and self-directed activity to avoid future functional limitations [8] [5] [3].
4. Prosthesis problems: loosening, malalignment, dislocation and instability
Mechanical issues with the implant — loosening, dislodgement, malalignment or instability — are listed among possible complications that can present during recovery and may demand additional assessment or revision surgery; surveillance during rehab includes clinical checks and, when indicated, imaging to confirm implant position and function [2] [3].
5. Complications from immobilization: pressure sores, lung effects and deconditioning
Beyond knee-specific problems, immobilization raises risks such as pressure ulcers, impaired pulmonary function and loss of general mobility. That is why many centers now adopt rapid‑recovery protocols and same‑day or early mobilization to reduce these secondary harms [4] [5].
6. Pain control and medication-related issues: balancing recovery and risks
Effective pain management is needed so patients can participate in therapy; however, analgesics and other perioperative medications carry side effects and risks (not exhaustively detailed in the supplied sources). Sources stress that pain should be controlled sufficiently to enable exercises like walking 20–30 minutes several times daily, which supports recovery [8] [5]. Available sources do not mention detailed drug-specific complication rates beyond general statements.
7. How modern protocols and technology change the complication picture
Rapid recovery pathways — including same‑day mobilization, blood‑preservation strategies, and self‑directed pedalling exercises — have been shown to reduce length of stay, postoperative pain and some complications without compromising safety, but these require structured protocols and monitoring [5]. Advances such as partial‑knee implants and newer implant designs are reported to have lower blood loss and lower rates of some complications (for example, some reports claim reduced DVT and infection with Oxford PKR versus total replacement), though those device‑specific claims are presented by institutional or promotional sources and should be weighed against independent data [6] [9].
8. Practical signs for patients and therapists to act on immediately
Patients and therapists should escalate care for signs of leg swelling or calf pain (possible DVT), increasing wound redness, discharge, fever (possible infection), sudden shortness of breath (possible pulmonary embolism), inability to achieve expected motion despite therapy (risk of lasting stiffness), or new instability around the joint (possible prosthesis problem) — all complications explicitly cited in patient-facing and clinical resources [1] [7] [2] [4].
9. What the sources disagree on or omit
Guidance is consistent that early mobilization reduces complications, but sources differ on the magnitude of device‑level benefit (e.g., promotional claims for Oxford PKR lower DVT/infection rates) and on long‑term comparative outcomes; those device claims come from an institution reporting early experience and should be contrasted with independent registry or peer‑reviewed evidence [6] [10]. Detailed incidence rates for each complication in specific modern rehab pathways are not provided in these sources — available sources do not mention precise, up‑to‑date complication percentages across different protocols.
10. Bottom line for clinicians and patients
Rehab teams must prioritize early, supervised mobilization, wound surveillance, DVT prophylaxis and graduated exercise to reduce common early complications; when new implants or rapid‑recovery protocols are used, teams should track outcomes carefully because promotional claims [6] and clinical reviews [5] [10] both influence expectations but are not interchangeable. Follow established institutional protocols and escalate immediately for the red‑flag signs listed above [1] [7] [2].