Total hip arthroplasty (THA) is one of the most successful orthopedic procedures to effectively relieve pain and restore function in patients with end stage osteoarthritis. In an attempt to accelerate recovery many orthopedic surgeons have opted to utilize a direct anterior approach (DAA) as opposed to the more traditional posterolateral approach (PLA). The literature supports that DAA is superior to PLA with regard to lower blood loss, less pain, shorter hospital stay, and faster rehabilitation. Traditionally the study team has performed Lumbar Plexus blocks (LPB) to provide post-operative analgesia for total hip arthroplasty. The quadratus lumborum block (QLB) is a newer regional analgesic technique that may be as effective as LPB at providing pain control following DAA hip arthroplasty. This study is designed to compare the efficacy, with regards to post-operative pain management, between LPB and QLB following a DAA total hip arthroplasty.

In an attempt to accelerate recovery many orthopedic surgeons have opted to utilize a direct anterior approach (DAA) as opposed to the more traditional posterolateral approach (PLA) in regards to total hip arthroplasty (THA). The DAA technique involves dissection of muscular planes for insertion of components resulting in less tissue damage as compared to PLA. Traditionally the study team has performed Lumbar Plexus blocks (LPB) to provide post-operative analgesia for total hip arthroplasty. This technique works well for the traditionally performed PLA in that the hip joint and incision site are within the analgesic distribution of the LPB. Conversely, the DAA utilizes an anterior incision that overlies the L1 and L2 dermatomes as opposed to the lower lumbar dermatomes of the PLA incision. When performing LPB it has been the study team's clinical experience that it is rare to achieve analgesia in the proximal distribution of the lumbar plexus resulting in apparent sparing of the L1 and L2 nerve root distributions. The quadratus lumborum block (QLB) is a newer regional analgesic technique that may be as effective as LPB at providing pain control following DAA hip arthroplasty. The QLB is thought to provide analgesia by blocking both the lateral and anterior cutaneous branches of T7 through L4. This degree of dermatomal coverage suggests that QLB could be an efficacious alternative to LPB for DAA hip arthroplasty. It is hypothesized that the QLB will provide equivalent analgesia when compared to the LPB as determined by a comparison of verbal reported pain scores.

Inclusion Criteria:

• Any patient between the ages of 18 and 95 years undergoing a primary elective, unilateral DAA total hip arthroplasty.

Exclusion Criteria:

• If the patient uses more than 40mg of Oxycodone equivalents per 24 hours or is on extended release opioid formulations.
• Indication for surgery is secondary to trauma and/or hip fracture
• If there is a contraindication to the performance of a regional block
• Concomitant anticoagulation use or documented coagulopathy
• Infectious or dermatologic conditions in the area of block placement that would otherwise increase the risk of peripheral nerve blockade
• Presence of progressive neurologic deficit effecting peripheral nerves
• Allergy or adverse reaction to study drugs to include: fentanyl, epinephrine, and amide local anesthetics
• American Society of Anesthesia Physical Classification score > or = to 4
• Allergies to study drugs other than local anesthetic
• BMI > 40
• Patient refusal
• Pregnancy
• Institutionalized individuals
• Extremes of age: Age > 95 or < 18
• Non English speaking or inability to reliably participate in the study