GAIT ANALYSIS OF MENINGOCOCCEMIA PATIENTS WITH AN ABOVE-KNEE PROSTHESIS ON ONE LIMB AND A BELOW-KNEE PROSTHESIS ON THE OTHER
WILLIAM R. OSEBOLD, MD; MARK L. McM ULKJN, PhD; CORY M.BARR, MPT; DONALD M. CHRISTENSON, CPO; SHRINERS HOSPITALS FOR CHILDREN, SPOKANE, WASHINGTON
We evaluated the gaits of five patients, all with video studies. Four of these five patients also had three-dimensional computerized gait analysis. Patients were nine months to six years old at the time of infection and amputation. They were five to ten years old at the time of study, weighed 18 to 84 kilograms, with heights of 104 to 150 cm.
On video, patients were seen to have increased anterior pelvic tilt. The above-knee prosthesis side hip extended in stance while the below-knee prosthesis side hip remained flexed. The above-knee side knee extended in stance, but in swing had increased flexion above normal, as a probable mass effect which helped with clearance. The below-knee side knee remained slightly flexed throughout the entire gait cycle.
On video, three patients showed full heel strike bilaterally, one had heel strike on the above-knee side only, and only one patient had no heel strike on either side. Stance width, torso and upper limb positioning, femoral rotation, and the degree of late stance dorsiflexion of the prosthetic feet, were all greatly variable among the five patients.
On video, all five patients tended to keep the above-knee side prosthetic knee extended throughout stance, probably as a stability mechanism. The below-knee side knee was maintained slightly flexed throughout the gait cycle, probably owing to knee stiffness, with contracture of hamstrings and the posterior capsule of the knee joint.
During this study, three patients graduated from crutch or walker ambulation to unsupported walking, and this was very encouraging.
On video, on back view, all five patients showed the plantar surfaces of the heels in late stance phase. On frontal views, three of the five patients showed the plantar surfaces of the metatarsal heads at heel strike. This was much more effective ambulation than the shuffling gaits that we had anticipated.
The patients spent about equal stance phase time on the below-knee limb (64% of the gait cycle), and above-knee limb (61% of the cycle), and these compared favorably to normal stance phase time of about 60% of the cycle. All four patients kept the feet wider than the pelvis in gait, possibly for increased base of support or for balance.
On kinematics, with the exception of the youngest patient, the four patients with computerized analysis showed extension of the above-knee side hip throughout stance, approximating normal. The below-knee side hip, however, remained flexed throughout the gait cycle.
In all four patients on kinematic study, the above-knee side knee remained extended throughout stance. Our two most accomplished ambulators showed increased flexion of the above-knee side knee during swing, again as a probable mass effect, which helped with clearance. The below-knee side knee remained flexed throughout the gait cycle.
All four patients tended to hold the above-knee side hip in greater abduction than normal throughout gait. And with one exception, the below-knee side hip was also held in abduction, probably as a balance mechanism.
Despite several encouraging findings during the study, the oxygen cost data made us worry about the future ambulation potential for our patients. We compared adjusted oxygen costs for bilateral traumatic adult below-knee amputees and bilateral traumatic adult above-knee amputees with oxygen cost data for normal children ages six to twelve years. We found that the adjusted bilateral below-knee amputee data indicated that bilateral below-knee amputees perform somewhat more efficiently than the fifth percentile of normal, while bilateral above-knee traumatic amputees are much more inefficient than normal.
We compared this data to our four patients with computerized analysis; we found that each of them performed more inefficiently than the fifth percentile of normal. Even our two most accomplished ambulators performed more inefficiently than the fifth percentile of normal, and were similar in comparison to the bilateral traumatic above-knee amputees.
Certainly the average oxygen cost for our four patients was very high, and much more inefficient than the fifth percentile of normal. We found that their oxygen cost made it almost too inefficient for our patients to walk. (R.L. Waters had noted in Jacqueline Perry's 1992 text that "bilateral vascular amputees rarely achieve a functional ambulation status if one amputation is at the above-knee level').
Therefore, we are concerned about the future ambulation potential of our four patients, as they become older and larger. In fact, our ten-year-old, who weighs 84 kg, has already decided to stop walking. We wonder if our patients will be similar to many myelomeningocele patients who reach adolescence and convert from ambulation to wheelchair mobilization.