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Total Hip Arthroplasty and Total Knee Arthroplasty: Rehabilitation Functional Outcomes

Adapted from a presentation given at HSS on April 28, 2006

  1. Introduction
  2. Evaluating Existing Tools for Measuring Functional Progress
  3. Developing a Tool Specific to HSS
  4. Functional Milestones
  5. Evolution of the Tool
  6. How Have We Used the Outcomes Data?
  7. Conclusion
  8. Resources


There are many ways in which we measure outcomes at Hospital for Special Surgery (HSS). We have Press Ganey surveys to gauge patient satisfaction, data collection from HSS physicians to track long-term outcomes, and standard indices which are often used for research purposes.

Yet the question was raised by the Rehabilitation staff in 1987, “Is there a tool to monitor functional progression following total hip arthroplasty (THA) in the acute care setting?” The focus of this lecture explains the answer to that question and the development of the Hospital for Special Surgery (HSS) Rehabilitation Functional Milestone Form that followed. We will also discuss trends in length of stay and how the tool helped us to track this information.

Existing Tools

Once the question of whether there was a tool to measure functional progress following THA in the acute care setting was raised, the Rehabilitation Department undertook a review of the current literature. The review found that in fact many tools or indices did exist, including but not limited to:

  • Barthel
  • Katz
  • Sickness Impact Profile (SIP)
  • Arthritis Impact Measurement Scale (AIMS)
  • Health Assessment Questionnaire (HAQ)
  • Functional Status Index (FSI)

However, these tools were found to have certain problems when applied to HSS’s needs, including the fact that they could take 15-30 minutes to complete and were not limited to the acute care setting or THA patients.

Developing a Tool Specific to HSS

It was decided that the HSS Rehabilitation Department needed to develop a tool of its own, one that would be valid, reliable, sensitive to change, and efficient to use.

A group of 20 HSS physical therapists was gathered for the task. The orthopedics experience of the group ranged from 1 to 15 years, with a mean of 5 years.

Selecting of Items

The group’s first step was the selection of items to be listed on the form. These items represent the tasks a patient would need to be able to perform independently prior to discharge. Dozens of tasks were considered, including:

  • The ability to turn to the side while lying down
  • Transferring supine to sit
  • Transferring sit to stand 
  • Transferring on and off the toilet
  • Standing with a walker
  • Ambulation with a walker 
  • Ambulation with crutches
  • Ambulation with a cane
  • Ascending/descending the stairs reciprocally without rails
  • Ascending/descending the stairs non-reciprocally with rails
  • Performing a bedside exercise program

In the end, five essential tasks where chosen which encompassed the broader activities required to be safely discharged home. It was also decided to record the patient’s day of discharge in order to track length of stay. These five tasks became known as the Functional Milestones:

  • Transfer (all transfers, including supine to sit, sit to stand, etc)
  • Ambulation with a walker
  • Ambulation with crutches
  • Ambulation with a cane
  • Stairs

Scaling of Items

Now that the items were selected, the group needed to define a scaling system to measure each patient’s level of progress. Just as many items were initially considered for inclusion, many levels of assistance were also considered, such as:

  • Maximal assistance
  • Moderate assistance
  • Minimal assistance
  • Assistance of 1 or 2 people
  • Close supervision
  • Distant supervision
  • Contact guard
  • Verbal cues

These were categorized down to 2 basic levels of assistance:

  • Assisted – Defined as any physical assistance, including contact guard, supervision, or verbal cues, with the use of an assistive device.
  • Unassisted –Defined as independent, i.e., not requiring the assistance of another person to perform the activity, but with the use of an assistive device.

Functional Milestones

In summary, below are the agreed-upon Five Functional Milestones and their correlating Levels of Assistance:

Transfer Assisted (TA)
Walker Assisted (WA)
Crutches Assisted (CRA)
Cane Assisted (CA)
Stairs Assisted (STA)
Transfer Unassisted (TU)
Walker Unassisted (WU)
Crutches Unassisted (CRU)
Cane Unassisted (CU)
Stairs Unassisted (STU)

Because this would be a tool for research, the reliability, validity, and sensitivity to change were tested. (1)

Once the Total Hip Arthroplasty Form was completed and tested, the Total Knee Arthroplasty (TKA) Functional Milestone Form quickly followed. While the forms were essentially the same, the following information was added on the TKA form:

  • CPM settings for flexion
  • Active Extension Right Leg
  • Active Flexion Right Leg
  • Active Extension Left Leg
  • Active Flexion Left Leg

Evolution of the Tool

The Total Hip Arthroplasty Functional Milestones form has undergone many changes over the last 18 years. The core of the tool remains the same, but the additional information we choose to collect is constantly changing to account for new techniques, anesthesia, demographics, pre-op information, etc.

The only change made to the actual milestones over the 18 years was the addition of “Stand Only” in 2005. With the use of femoral nerve blocks, many TKA patients could not ambulate postoperatively on day one because of quad weakness that resulted in buckling of the lower extremity.

How have we used the Outcomes Data?

Development of Clinical Pathways and Protocols

The information available from the functional milestone database proved to be critical in the development of the clinical pathway, as we could anticipate when patients would be ready to advance to the cane or the stairs. This information was the catalyst for the development of a multidisciplinary clinical pathway based on evidence we had collected.

Once the multidisciplinary clinical pathway was developed, the physical therapy portion was extracted to create our THA protocol.

Development of Documentation Tools

Knowing the anticipated day of achievement of various functional activities, a packet of documentation forms was developed.

The theory behind the tools was that if a patient followed the designated clinical pathway, there would be very little documentation to complete in a long hand version. Activities that should occur on each day were put into that day’s documentation form. If the patient achieved this activity, it would be checked or answered with yes/no or a brief comment.

Conversely, if a patient did not achieve the level expected on a particular day, the therapist would have to document why the expected activity was not initiated or continued, or independence achieved.

This has greatly reduced the amount of time needed for documentation.

Reduced Length of Stay

Taking a look at the last 10 years of data shows a trend toward the earlier achievement of functional milestones and a decreased length of stay.

Ten years ago, patients would reach independence and remain in the hospital for an additional 1.5 days. With education and a hospital-wide, multidisciplinary approach to reducing length of stay, that gap has closed to less than ½ of a day. Length of stay for 2005 was 4.2 days for THA patients and 5.1 for TKA patients.

Orientation Process for New Graduate Hires and New Hires in General

Comparing the rate of progression of experienced therapists with inexperienced therapists, we found that there was a slower rate of progression for the inexperienced therapists. As a result, a clinical ladder was developed creating senior therapist positions.

Orientation and mentoring processes were enhanced, pairing a senior PT with a new PT for an orientation period of 4-6 weeks. Ongoing case review was also implemented.


Finally, there is research, which was one of the original goals in developing this functional milestone form. Below is an example of a recent study that a PT participated in at HSS (2):

This prospective, randomized, blinded study featured 2 groups:

  1. CSE + Epidural PCA (n=39)
  2. CSE + Epidural PCA + FNB (n=41)

PT intervention was the same for each group. The results showed the following:

  • Statistical difference in knee flexion ROM POD#2
  • Improved pain relief with PT for first two days
  • No delay in achievement of functional milestones related to the FNB

Other examples of research using the Functional Milestone form can be found in the additional publications listed at the end of this article.


Since the Total Hip Arthroplasty-Functional Milestones form was introduced in 1987, many changes have taken place in the Rehabilitation Department and at HSS at large. Procedures, protocols, standards of care, patient expectations, and length of stay expectations are just some of the areas where these changes have been observed.

Thanks to the foresight of the therapists who first developed it, the Total Hip Arthroplasty-Functional Milestones form has proved to be a valid, reliable tool, answering many clinical questions and providing a critical component to therapist-driven clinical research. The HSS Rehabilitation Department looks forward to following this model by initiating further studies and projects in the years to come.


  1. A tool for measuring functional outcomes after total hip arthroplasty. Arthritis Care and Research. Vol 7 #2 June 1994:78-84. Kroll MA, Ganz SB, Backus SI, Benick RA, et al
  2. “The Effects of Femoral Nerve Blockade in Conjunction with Epidural Analgesia After Total Knee Arthroplasty” (YaDeau, Cahill, et al. Anesth Anag, Sept 2005)

Additional Resources

The day of discharge after total hip arthroplasty and the achievement of rehabilitation functional milestones: 11-year trends. The Journal of Arthroplasty. Vol 18 #4 2003:453-457. Ganz SB, Wilson Jr PD, Cioppa-Mosca J. Peterson MGE

A historic look at functional outcome following total hip and knee arthroplasty. Topics in Geriatric Rehabilitation. Vol 20, #4 Oct-Dec 2004:236-252. Ganz SB

Randomized trial of epidural versus general anesthesia. Outcomes after primary total knee arthroplasty” CORR. 1996. Russo, Sharrock, Ganz, et al.

Summary by Dana Gallagher


Karen Juliano, PT
Clinical Supervisor of Education
Rehabilitation Department
Hospital for Special Surgery


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