Hi Laura

Great question! It would be wonderful to predict these outcomes. Can I suggest you check out this reference which points to some predictors (but gives no firm answers):

 Bawa, Wera, Kraay, Goldberg (2013) "Predictors of Range of Motion in Patients Undergoing Manipulation After TKA" Clin Orthop Relat Res (2013) 471:258–263.

It would make a great retrospective study, though, wouldn't it?

Hope this helps

David

Hi Laura,

Another aspect is the pre-operative patient education. We saw that pre-operative patient education was associated with a decreased risk of a stiff knee after TKA. Livbjerg et al. in J Arthroplasty. 2013 Sep;28(8):1282-5.

Here is the link:

http://www.ncbi.nlm.nih.gov/pubmed/23507064

Postoperative factors potentially leading to knee stiffness include poor patient motivation and/or selection, deep infection, heterotopic ossification, pain management regimen and aggressive anticoagulation therapy which may result in the development of intra-articular hematomas with secondary stiffness.

Some patients who develop post-operative stiffness require manipulation under anesthesia to address this issue. The best candidate for maninpulation is a motivated patient with a restricted ROM detected within 3 months of surgery. A minimum of 90° of flexion is required to negotiate stairs and sit comfortably; therefore, patients who have failed to achieve at least 90° of flexion following surgery are candidates for manipulation. Patients I have seen in physical therapy, manipulation has seemed to work better to correct restricted flexion than to overcome a flexion contracture. During manipulation, increased motion is achieved through mechanical lysis of intra-articular adhesions, thus manipulations that are performed within the first 3 months of surgery tend to be safer and more efficacious than those performed at a later time. In additional, the first manipulation tends to be more successful that subsequent ones. It is paramount that the patient initiates an intensive physical therapy program after manipulation. Post-manipulation, patients typically participate in a physical therapy program with five visits per week for 2 to 3 weeks, followed by three visits per week for an additional 2 to 3 weeks. It is also crucial that patients perform home exercises, use cold packs and have good pain control. Manipulation is successful in controlling pain and increasing range of motion in 75% to 90% of cases. Unfortunately, some patients, even a few without predisposing factors for stiffness will develop arthrofibrosis, a complication that is still poorly understood.

Overall, patients who get between 128 and 132 degrees of knee flexion seem to have good function for everyday activities. 

Joint replacement surgeons track rangeof motion post-op in knee replacement.  If the ROM is not good or decreasing an MUA is considered.  Earlier is better than later.

Apart from the usual causes already mentioned, warfarin usage and also the inability to take NSAIDs are the commonest reasons I see clinically for patients not comfortably obtaining 90degrees bend at 6 week follow-up. These patients are frequently in the 80-90 degrees range and if urgent intensive Physio is implemented they can often get over 90 degrees in the next week or two and avoid MUA. This is a different group from the very stiff knees where infection has to be excluded and where pain control issues and severe pre-op stiffness or technical problems with the surgery  are more likely to be implicated.

Once other peri-operative risk factors (as per above and above all patients pre-op ROM) are covered then as per Michael Skovdal Rathleff; pre-operative education is key. Too many patients are not expecting the reduced range that a TKR often provides and the extremely hard work required to even reach that.

In our experience following an Enhanced Reovery Programme for TKA, only 2 patients from a cohort of 1081 consecutive TKA required MUA at or before 6 weeks post surgery. all patients followed a comprehensive Enhanced Recovery Programme with specific discharge criteria including a minimum 80 degrees flexion and SLR. the most important factors as stated above are pre-operative eduaction clearly defining the expected outcome, multimodal analgesia that allows early ambulation and active mobilisation of the joint and early rehabilitation.