Knee Replacement Complications

(also known as total knee arthroplasty) is generally a highly successful procedure with excellent long-term results. In a recent study, 97% of patients remained “revision-free” at 10 years 1. Despite these favorable outcomes, complications may still occur. Listed below are some of the more common complications of total knee replacement surgery.

Infection

Several steps are taken to prevent infection. For example, antibiotics are often given before, during and after knee replacement surgery. Still, a small percentage of knee replacements become infected. In a recent study of over 3000 replacements, 2.9% experienced “superficial” infections while 0.8% of infections occurred within the joint. An increased rate of infection was observed in patients who experienced complex surgery or who had certain characteristics such as obesity or poor pre-operative health. 2

Loosening

Knee replacement components are affixed to the bone in two ways. In “press-fit” implants, long term fixation relies on the growth of bone into what is typically a porous surface or coating on the underside of the implant. Alternatively, the implants may be “cemented” into place with a strong polymer (PMMA) which is mixed and applied at the time of surgery. Both of these fixation methods can fail over time for a variety of reasons causing the implant to become loose and requiring revision (see Implant Poly Wear)

DVT

Deep Vein Thrombosis (DVT) is a rare but potentially very serious complication. Blood clots (thrombus) can sometimes form in the “deep” veins near the surgical site. This can cause pain, redness and swelling. Sometimes, the clot can become dislodged and travel through the bloodstream and into the lungs where it can become trapped. This is called a pulmonary embolism and can be fatal. Obviously, many, many precautions are taken to prevent this serious complication.

Patellar Clunk Syndrome

This complication involves interaction of the scar tissue at the top of the patella with the femoral component. See our article on Patellar Clunk Syndrome for more information.

Joint stiffness

Obviously, the joint will be soar and relatively stiff immediately after surgery, however, limited flexion after the immediate post-operative period is undesirable. To read more on stiffness following knee replacement surgery, visit our article joint stiffness following knee replacement surgery.

Allergic Reaction

A small number of patients may experience an allergic reaction or hypersensitivity to the metallic elements in the implants. A more detailed explanation of this complication can be found our article on this topic.

1 Barrington JW, SahA, Malchau H, Burke DW. Contemporary cruciate-retaining total knee arthroplasty with a pegged tibial baseplate. Results at a minimum of ten years. JBJS (Am.). 2009;91:874-878.

2. Jämsen E, Varonen M, Huhtala H, Lehto MU, Lumio J, Konttinen YT, Moilanen T. Incidence of Prosthetic Joint Infections After Primary Knee Arthroplasty.  J Arthroplasty.2008 Dec 3.

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Joint Stiffness: Complications Following Knee Replacement Surgery

In a relatively recent article 1 published in the Musculoskeletal Journal of Hospital for Special Surgery, Dr. Alejandro Gonzalez Della Valle et al reviewed the origins of and treatments for early onset stiffness,  a common complication following knee replacement surgery. We’ll present a brief summary of the article here.

How Prevalent is Stiffness after Knee Replacement?

In a review of the literature, the authors state that stiffness occurs in roughly 6% of cases, making it the most common knee replacement surgery complication.

How is Stiffness Defined?

The researchers reveal that what is perceived as “stiffness” following knee replacement has evolved over time. Several years ago, a knee was considered stiff if the patient could not extend their knee beyond 25 degrees of flexion (that is, a flexion contracture of 25 degrees) or if the full arc of motion was less than 45 degrees. More recently, as surgical technique and implant design have improved and as younger, more active patients receive implants, expectations have changed. Today, stiffness has been defined as a equal to or greater than only 10 degrees or an arc of motion less than 95 degrees. The authors note that this degree of motion is what is required for common activities of daily living (walking, sitting, stair climbing). Practically speaking, a joint can be considered “stiff” when it limits the patient’s ability to perform such activities.

What Causes Stiffness after Knee Replacement?

The authors place the causes of stiffness into three broad categories:

Preoperative – These include things like post-traumatic osteoarthritis, patients with prior high tibial osteotomy and patient whose preoperative range of motion (ROM) is limited.

Intraoperative – Included here are what the authors termed “technical errors” during the procedure. Things like, improperly sized implants and poor “balancing” of the joint through improper bone preparation fall into this category. The researchers explain these as well as other technical errors in detail.

Postoperative - Following surgery, stiffness can be caused by additional factors. Some examples are by patient behavior (“poor patient motivation”) deep infection and inadequate pain management.

How is Stiffness Treated

The authors then outline the various ways in which stiffness can be treated following knee replacement. Manipulation of the knee by the surgeon under anesthesia is generally successful when used within the first three months after surgery. After this period, more aggressive surgical options should be considered since manipulation can result in fracture or soft-tissue damage. Some surgical treatments described are arthroscopy, tibial insert (or spacer) exchange and revision surgery (i.e. exchange of the femoral component typically to correct imbalance in the spacing between the thigh and shin bone created at the time of surgery). The authors also stress the importance of proper rehabilitation following knee replacement.

The original article is available online through PubMed Central.

1. Gonzalez Della Valle A, Leali A, Hass S: Etiology and Surgical Interventions for Stiff Total Knee Replacements. HSSJ 2007, 3: 182-189

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