Multiple factors may lead to stiffness after total knee arthroplasty (TKA), including patient diagnosis, preoperative range of motion (ROM), prosthetic geometry used, surgical technique, intraoperative ROM after capsular closure, postoperative rehabilitation, and wound healing factors. An ipsilateral arthritic hip can also inhibit postoperative recovery and lead to knee stiffness.
Exposure of the ankylosed knee can be difficult. One must take care to avoid excessive stress on the patellar tendon insertion leading to patellar tendon avulsion. The 2 most common methods to facilitate exposure are a proximal release or a tibial tubercle osteotomy.
When patients fail to achieve satisfactory ROM after TKA, manipulation under anesthesia is considered. It is usually performed approximately 6 weeks postoperatively. The best indicator of each patients potential is his or her intraoperative flexion against gravity with the capsule closed at the end of the procedure.
When discussing stiffness associated with total knee arthroplasty (TKA), it is important to know what range of motion (ROM) is required for activities of daily living. One needs 70° of knee flexion to walk normally on level ground, 90° to go up most stairs, 100° to come down those stairs, 105° to get up from most chairs, and 115° to get up from a low sofa.
A number of factors may lead to stiffness after TKA, including patient diagnosis, preoperative ROM, prosthetic geometry, surgical technique, quadriceps excursion achieved at surgery, postoperative rehabilitation, and wound healing problems. Other factors include patient pain threshold, patella infera, ipsilateral hip involvement, the rare development of heterotopic ossification, and overzealous physical therapy.
The diagnoses most frequently associated with stiffness are juvenile rheumatoid arthritis, rheumatoid arthritis in some adults, psoriatic arthritis, and post-traumatic arthritis with multiple prior surgeries.
As far as ipsilateral hip involvement is concerned, one must always remember to evaluate each patient for an arthritic hip preoperatively. A good screening question to ask patients is, Can you easily tie your shoes and cut your toenails? If they can, an arthritic hip is unusual. Obviously, hip pathology is also screened by the physical examination and a radiograph, if appropriate.
Heterotopic bone formation is rare and may be the result of violating the periosteum above the trochlear groove with too aggressive a dissection (Figure 1).
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Figure 1: Heterotopic bone formation on the anterior cortex of the distal femur limiting postoperative flexion. Figure 2: A smooth pin placed in the tibial tubercle can help prevent avulsion of the patellar tendon during exposure of a stiff knee.
When exposing the stiff knee, whether ankylosed in extension or flexion, there is a choice between proximal release and tibial osteotomy. If a standard medial parapatellar arthrotomy is used, a short proximal inverted V incision can be used as a variation of a quadriceps snip.1,2 This has the advantage of facilitating a V-Y quadriceps lengthening, if appropriate.3 Even if a proximal release is performed, it is prudent to insert a smooth tubercle pin to prevent avulsion of the patellar tendon during the procedure (Figure 2).
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Figure 3: A trial femoral component can be used as a template to remove posterior femoral osteophytes and uncapped posterior condylar bone. Figure 4: Flexion against gravity after capsular closure is a good indicator of quadriceps excursion and potential flexion achievable postoperatively.
To expose the ankylosed knee that has poor flexion, the inverted V quadriceps incision or tubercle osteotomy is initiated. As exposure progresses, the knee is gently manipulated into more flexion. A joint line osteotomy is performed if there is bony ankylosis, and the anterior cruciate ligament, if present, is released along with intercondylar scar tissue. Maximum trochlear and patellar resection can be helpful to increase the quadriceps excursion along with a V-Y quadriceps lengthening, if appropriate.3
When exposing the knee that is ankylosed in extension, the inverted V with a tubercle pin or tubercle osteotomy is initiated. Tibia-first resection may be necessary, applying little or no posterior tibial slope since every degree of posterior slope will build in a degree of flexion contracture. The posterior cruciate ligament is resected, the posterior femoral and tibial osteophytes are removed, and the posterior capsule is stripped, if necessary. Removing posterior femoral osteophytes can create clearance for increased flexion, but also allows release of the capsule for more passive extension. The femoral trial can be used as a template to remove the femoral osteophytes (Figure 3).
Increasing the distal femoral resection allows a greater extension space without affecting the flexion space. One study has shown that removing 2 mm more of distal femur can increase passive extension by approximately 10°.4 It is inappropriate to remove much more than a total of 14 mm of distal femur (depending on the size of the patient) to avoid compromise of the medial collateral ligament origin. Excessive distal femoral resection can also create a flexion/extension mismatch that mandates the use of a constrained condylar type of articulation.
Correction of a severe flexion contracture can also result in a significant extensor lag. This can be minimized by modification of the capsular closure. Initial capsular alignment is established at the time of the arthrotomy with a sterile marking pen or tagging sutures. At the time of capsular closure, the medial capsule is advanced distally on the lateral capsule, thereby reestablishing patellar tendon tension.
Knee manipulation is occasionally required for the postoperatively stiff knee. The incidence of its need will vary with the patient population and the threshold of the operating surgeon. It is usually performed between 4 and 6 weeks postoperatively. Before proceeding with a manipulation, it is important to know the patients intraoperative potential, which reflects the knees quadriceps excursion. This is determined by measuring and recording knee flexion against gravity after capsular closure and indicates individual flexion potential (Figure 4).5 If a patient fails to achieve that potential or a functional ROM at 4 weeks, he or she is scheduled for a manipulation under anesthesia 2 weeks later.
The causes of stiffness after TKA are multifactorial. Problems can be anticipated preoperatively. The problem can be minimized by taking certain intra- and postoperative measures in surgical technique, prosthetic design, and rehabilitation.
- Garvin KL, Scuderi G, Insall JN. Evolution of the quadriceps snip. Clin Orthop Relat Res. 1995; (321):131-137.
- Scott RD. Stiffness before and after Total Knee Arthroplasty. In: Scott RD. Total Knee Arthroplasty. Philadelphia, PA: Elsevier; 2006:63-68.
- Scott RD, Siliski JM. The use of a modified V-Y quadricepsplasty during total knee replacement to gain exposure and improve flexion in the ankylosed knee. Orthopedics. 1985; 8(1):45-48.
- Bengs BC, Scott RD. The effect of distal femoral resection on passive knee extension in posterior cruciate ligament-retaining total knee arthroplasty. J Arthroplasty. 2006; 21(2):161-166.
- Lee DC, Kim DH, Scott RD, Suthers K. Intraoperative flexion against gravity as an indication of ultimate range of motion in individual cases after total knee arthroplasty. J Arthroplasty. 1998; 13(5):500-503.
Dr Scott is from Harvard Medical School, Boston, Massachusetts.
Dr Scott has no relevant financial relationships to disclose.
Presented at Current Concepts in Joint Replacement 2008 Winter Meeting; December 10-13, 2008; Orlando, Florida.
Correspondence should be addressed to: Richard D. Scott, MD, Harvard Medical School, 125 Parker Hill, Boston, MA 02120.