Severity and location of lumbar spine stenosis affects the outcome of total knee arthroplasty

• Published in: Journal of orthopaedic surgery and research Vol. 16; no. 1; p. 720
• Main Authors: Sheppard, William L, McKay, Kevin M, Upfill-Brown, Alexander, Blumstein, Gideon, Park, Howard Y, Shah, Akash, Sassoon, Adam A, Park, Don Y
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 20.12.2021; BioMed Central; BMC
• Subjects: Age; Aged; Aged, 80 and over; Anesthesia; Arthritis; Arthroplasty (knee); Arthroplasty, Replacement, Knee - adverse effects; Asymptomatic; Back pain; Back surgery; Body mass index; Bone surgery; Constriction, Pathologic; Demographics; Diabetes; Female; Humans; Hypertension; Joint replacement surgery; Joint surgery; Knee Joint; Lumbar Vertebrae - diagnostic imaging; Lumbar Vertebrae - surgery; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Medical research; Medicine, Experimental; Morphology; Narcotics; Orthopedics; Osteoarthritis; Osteoarthritis, Knee - diagnostic imaging; Osteoarthritis, Knee - surgery; Osteoporosis; Outcomes; Patient satisfaction; Patients; Retrospective Studies; Spinal stenosis; Spinal Stenosis - diagnostic imaging; Spinal Stenosis - surgery; Spine (lumbar); Stenosis; Surgeons; Total knee arthroplasty; Treatment Outcome; Total knee arthroplasty; Outcomes; Spinal stenosis
• ISSN: 1749-799X; 1749-799X
• DOI: 10.1186/s13018-021-02864-x

Recent studies have noted that patients with pre-existing lumbar spinal stenosis (LSS) have lower functional outcomes after total knee arthroplasty (TKA). Given that LSS manifests heterogeneously in location and severity, its influence on knee replacement merits a radiographically targeted analysis. We hypothesize that patients with more severe LSS will have diminished knee mobility before and after TKA. This retrospective case series assessed all TKAs performed at our institution for primary osteoarthritis from 2017-2020. Preoperative lumbar magnetic resonance image (MRI) with no prior lumbar spine surgery was necessary for inclusion. Stenosis severity was demonstrated by (1) anterior-posterior (AP) diameter of the thecal sac and (2) morphological grade. TKA outcomes in 103 cases (94 patients) were assessed by measuring preoperative and postoperative arc of motion (AOM), postoperative flexion contracture, and need for manipulation under anesthesia. Patients with mild stenosis did significantly better in terms of postoperative knee AOM. As AP diameter decreased at levels L1-2, L2-3, L3-4, and L4-5, there was a significant reduction in preoperative-AOM (p < 0.001 for each), with a 16 degree decrease when using patients' most stenotic level (p < 0.001). The same was noted with respect to increased morphological grade (p < 0.001), with a 5 degree decrease for patients' most stenotic level (p < 0.001). Severe LSS, which is readily demonstrated by a reduction in the AP diameter of the thecal sac or increased morphological grade on MRI, correlated with a significant reduction in preoperative AOM that was not improved after TKA. Persistent postoperative reductions in AOM may contribute to reduced patient satisfaction and recovery. Level 4.