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#011- Total Hip Arthroplasty and Dynamic Knee Valgus

Covered Topics:

1. Accelerated Rehabilitation Program for Total Hip Arthroplasty.

2. How to Reduce Dynamic Knee Valgus.

Estimated reading time: 5 minutes, 48 seconds.

Articles

Accelerated Rehabilitation Program for Total Hip Arthroplasty

This RCT (PEDro score 7/10) compared an accelerated rehabilitation program to a standard program post total hip arthroplasty.

Protocols

  • Standard Group Protocol
    • Day 1: Started 4 hours after discharge from anesthesia recovery unit, Participant received verbal orientation and demonstration of strengthening exercise for gluteus and thighs, 3 repetitions of 12 complete movements for each exercise from supine or sitting.
    • Day 2: similar to day 1, added gait training if patient felt safe and pain was controlled, if not, gait training was postponed to the next day.
    • Day 3 until discharge, similar exercise and gait training.
  • Accelerated Group Protocol consisted of 3 approaches
    • Similar exercise was to the standard group protocol for but done 3 times/day

Results:

23 participants in the Accelerated Rehabilitation Program (ARP) and 25 participants in the Standard Program. (SP)

  • ARP group in-hospital stay was less than SP group.
  • 3 patients from SP group and 1 patient from ARP group had deep venous thrombosis post-op.
  • No difference between groups in pain post-op.
  • No difference between groups for ROM.
  • ARP had better muscle strength than SP groups, in 3 muscle groups: abduction, external rotation and internal rotation.

Learned from this article:

An accelerated program might improve hip muscle strength, earlier gait training and decrease the length of stay in hospital.

Note:

This program was after posterior incisions approach for total hip arthroplasty.

How to Reduce Dynamic Knee Valgus

Dynamic knee valgus (DKV) is a movement pattern of the lower limb, potentially comprised of a combination of adduction and internal rotation of the femur, abduction of the knee, anterior tibial translation, external tibial rotation and ankle eversion. During this pattern, medial knee displacement is observed, beyond the foot-thigh line, which indicates knee valgus movement.

DKV can be a risk factor for acute and chronic injuries such as non-contact ACL injury and patellofemoral pain.

Knee Valgus can result from increased tension in tensor fascia latae causing tibial abduction.

Dynamic valgus can cause patella maltracking, moreover, with overload, dynamic knee valgus increases stress on the patellofemoral joint and retinaculum causing Patellofemoral pain.

  • Impact of the Neuromuscular Trunk Control on Knee Kinetics
    • A lack of adequate neuromuscular trunk control and excessive lateral flexion of the trunk in the frontal plane predisposes to a shift in the center of gravity of the body away from the knee during squatting or landing. Shifting the center of gravity laterally to the knee joint is also associated with shifting ground reaction forces (GRF) in the same direction, which in result causes knee valgus movement.
  • Hip Strength and Muscle Activation as Causes of the Incorrect Movement Pattern of the Knee
    • Movement of the hip joint depends mainly on gluteus muscles, gluteus muscles function to contradict dynamic knee valgus movement by hip abduction and external rotation.
    • Weakened hip abductors may affect the compensatory movement of pelvic drop and lateral torso displacement, this still controversial in the literature, where some studies found a link between the occurrence of dynamic valgus in single-leg tasks and weak hip strength, while others were unable to find that link definitively, later on, results from other studies indicate that the link depends on movement task tested, a systematic review and meta analysis found a link between hip muscle strength and knee valgus in ballistic single-leg landing tasks, and to minor size single-leg squat and not in ballistic double-leg tasks, also in healthy women groups, decreased strength of hip abductors, extensors and external rotators was associated with dynamic knee valgus during single-leg drop landings.
  • Regarding the of Quadriceps and Hamstring in stabilizing the Knee, in summery, the evidence is conflicting, where some studies support the hypothesis that muscular imbalance in medial-to-lateral quadriceps-hamstring co-contraction may contribute to increased knee valgus among recreationally active women, and other did not find the same results.
  • Ankle ROM impact: 2 studies found that dorsiflexion ROM restriction is associated with dynamic knee valgus.

Exercise to Reduce Dynamic Knee Valgus

  • Visual-Biofeedback by performed single-leg squat, double-leg squat, single-leg, and lateral step down while observing the correct movement pattern on a screen (3-D analysis system), decreased knee abduction angle by 6.16 degrees in landing phase.
  • Functional knee exercise (double leg squatting to single leg squatting) can reduce dynamic knee valgus by 10 degrees, while isolated hip abductor strengthening reduced dynamic knee valgus by 5 degrees in single leg stand test.
  • Gluteus medius and maximus training that includes side-lying hip abduction, quadruped leg extension, clam exercise and front step-up, for 3 times/week for six weeks can reduce the valgus angle from approximately 12.76 degrees to 7.28 degrees, also doing the same exercises but in front of a mirror (visual biofeedback) can reduce the valgus angle from approximately 13.34 degrees to 8.81 degrees.
  • Core muscle training consisting of Nordic exercise, side plank and front plank for 4 times/week for 8 weeks, can reduce valgus angle from 5 degrees to 2.2 degrees as measured using the single leg squat test, but that reduction was not shown in the double-legged DVJ test (study sample =17 female basketball players).
  • A combination of different types of exercises such as muscle strengthening, balance, proprioception and plyometric training with the addition of positioning feedback that emphasize avoiding knee valgus can be beneficial in reducing the risk of lower limb injuries.

Final Note

  • The first article gave a simple accelerated rehabilitation program for total hip arthroplasty patients, by simply repeating the exercise 3 times a day and initiating gait training as early as possible, you can decrease the patients in hospital stay and improve hip muscle strength.
  • The second article proved the importance of knee valgus assessment and its role in lower limb injuries, while providing some evidence on how to reduce dynamic knee valgus to prevent injuries such as ACL and patellofemoral pain.

Trends

  • The term “Total Hip Replacement” is far more popular (searched) than “Total Hip Arthroplasty”. (Maybe I should have used Total Hip Replacement instead of Total Hip Arthroplasty to get more hits).
  • Knee valgus was most searched in Australia, with the most related inquiry being valgus knee deformity.

Recommended reads:

References

  1. Accelerated rehabilitation versus conventional rehabilitation in total hip arthroplasty (ARTHA): a randomized double blinded clinical trial. (Open Access)
  2. Dynamic Knee Valgus in Single-Leg Movement Tasks. Potentially Modifiable Factors and Exercise Training Options. A Literature Review. (Open Access)

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