Short-term outcomes for total knee arthroplasty patients with active extension lag.

BACKGROUND: Despite the success of total knee arthroplasty (TKA), quadriceps strength can fail to recover. Active extension lag [quadriceps lag (Q-lag)] is a function of quadriceps weakness. Q-lag presents itself in patients who maintain a full passive range of motion (ROM), but are limited in active extension ROM. Few studies have evaluated the outcomes of post-TKA patients in the presence of post-operative Q-lag. Thus, this study aims to compare: (I) pain scores; and (II) rates of readmission to physical therapy (PT) in TKA patients with Q-lag of ≥15 degrees to patients without Q-lag. METHODS: A retrospective review of primary TKA patients between 2013 and 2015 was performed. A total of 150 patients (mean age 63.0 years) with a mean follow-up of 30.7 months were analyzed. All patients received an evidence-based protocol for PT at our institution. Patient readmission to PT was recorded if the orthopedic surgeon wrote an additional prescription for PT intervention following the standard of care following TKA. An independent samples t-test and chi-square analysis was conducted to assess the continuous and categorical variables, respectively. RESULTS: Fifty-one patients had Q-lag ≥15 degrees and 97 patients had Q-lag <15 degrees. Analysis of mean pain scores between the groups demonstrated a significant difference in mean pain scores (1.9 vs. 3.9; P=0.043). Chi-square analysis demonstrated no significant difference in rates of PT readmission between patients who presented with Q-lag, and patients without Q-lag (23.5% vs. 13.4%; P=0.118). CONCLUSIONS: There was no significant difference in readmission rates; however, patients with Q-lag experienced a clinically significant higher pain level. Since this is the first study of its kind, we suggest further investigations on the effect of Q-lag on patient outcomes following primary TKA.

Nonpharmacologic Pain Management and Muscle Strengthening following Total Knee Arthroplasty.

Despite technological advances in total knee arthroplasty (TKA), management of postoperative muscle weakness and pain continue to pose challenges for both patients and health care providers. Nonpharmacologic therapies, such as neuromodulation in the form of neuromuscular electrical stimulation (NMES) and transcutaneous electrical nerve stimulation (TENS), and other modalities, such as cryotherapy and prehabilitation, have been highlighted as possible adjuncts to standard-of-care pharmacologic management to treat postoperative pain and muscle weakness. The aim of this review was to discuss existing evidence for neuromodulation in the treatment of pain and muscular weakness following TKA, and to shed light on other noninvasive and potential future modalities. Our review of the literature demonstrated that NMES, prehabilitation, and some specialized exercises are beneficial for postoperative muscle weakness, and TENS, cooling therapies, and compression may help to alleviate post-TKA pain. However, there are no clear guidelines for the use of these modalities. Further studies should be aimed at developing guidelines or delineating indications for neuromodulation and other nonpharmacologic therapies in the management of post-TKA pain and muscle weakness.