Twenty Months Experience with the "PTS"
Sam E. Hamontree, C.P. *
Howard J. Tyo, C.P. *
Snowdon Smith, C.P. *
Many questions have been asked of prosthetists in our area about the "PTS Prosthesis," since it was first presented by Marschall and Nitschke in the June, 1966 and March, 1967, Orthopedic and Prosthetic Appliance Journal. We note that many people prefer to use other terms for this prosthetic fitting, such as "Modified PTB Prosthesis with Molded Supra-condylar—Supra-patellar Suspension," but for the sake of brevity, and not desiring to argue the point of terminology here, we will use the term of the original authors, "PTS".
The technical aspects of the PTS have been well presented by these two gentlemen in Journal Articles, National Assemblies, and Regional Meetings in the past. Therefore, we will not even touch on technical aspects, but confine ourselves to answering those questions concerning, "how extensively have you used the PTS, what type of patients and stumps can be fitted with it, how successful has it been, how do you, as a prosthetist, like the PTS, etc.?"
The following charts show statistics on each individual patient fitted with a PTS Prosthesis in our two facilities in Syracuse and Rochester, during a twenty-month period from May, 1966, through December, 1967.
Ninety-four patients (28 female and 66 male) are shown in this study, of which three were bilateral below-knee amputees fitted bilaterally with the PTS, making a total of ninety-seven below-knee stumps fitted with the PTS prosthesis. These ninety-seven represent 100% of all PTS attempted, and 35% of the total number of below-knee prostheses fitted during the same period. At the same time, 26% of all BK amputations were fitted with PTB, and 39% had side joints and thigh lacer incorporated into their prostheses.
All ninety-seven were prescribed by, and followed to various extents, by a prosthetic clinic or an individual physician. None of the patients were selected on the basis of being used in a study, but were selected, utilizing normal prescription criteria, and with the intent that the PTS was the best prosthesis for the individual. However, some were prescribed when chronic stump problems persisted with other types of prostheses, and no other alternative was found.
The age shown in the chart is the patient age at the time of the first PTS fitting. The ages range from seven to eighty-nine, and average fifty-two. There was no reluctance to fit someone younger than seven, but there were none presented. Age did not appear to be a significant criterion in the prescription, fitting, or success of the prosthesis.
The amputation date shown in the chart is the last amputation or major surgical revision of the stump, prior to PTS fitting. The length of time between surgery and prosthetic fitting did not appear to be any greater or any less with the PTS. Neither did stump shrinkage, or atrophy appear to cause any greater need for, or less need for, replacement sockets.
Many of the listed causes of amputation are very general, but we think sufficiently self-explanatory for this paper. No evidence was found that would indicate that the PTS should, or should not, be used with any specific cause of amputation. It was noted numerous times, in patients who had previously shown problems of edema or breakdown at the distal end of the stump, that when they were fitted with the PTS, the problem areas cleared up and the problems were eliminated. In our opinion, this indicates less proximal restriction in this prothesis.
Stump lengths were measured from the medial tibial plateau to the end of the stump and these ninety-seven range from a short 2 3/4 inches to a long 12 inches. We found that we could successfully fit many short stumps with the PTS, which we could not fit with the PTB. Long stumps presented no problems in donning and removing the PTS, as some people had anticipated.
Twenty-one preparatory prostheses were fitted, fifteen PTS and six PTB. Some of the preparatory sockets were plaster of Paris and some with soft inserts, but no record was kept on how many of each. The decision to fit or not to fit preparatory prostheses was determined merely by the physician's opinion of "early fittings" and is incidental to this paper.
In forty cases, the PTS was the first type of prosthesis fitted (including preparatory PTS). Fourteen cases changed directly from a prosthesis with side joints and thigh lacer, and forty-three from PTB. A discussion of these results follows in later paragraphs.
Occupational classifications are general and fail to show the activities followed by the individual, which in many cases does not indicate how extensively the prosthesis is being used. While classifications such as Construction and Machinist indicate hard use of a prosthesis, the term Retired would tend to indicate light use, however, in many of these Retired cases it means more extensive use, such as part time jobs, or hunting, fishing, etc.
We have attempted to evaluate the Results Column very realistically and without prejudice. While judgment enters into this considerably, we have in all cases arrived at the result after consultation with the patient and/or the physician.
In only eleven instances out of the ninety-seven, the PTS was not the prosthesis of preference to the patient. However, two of the eleven are still wearing it. These two patients preferred the PTB to the PTS, but rather than altering their present PTS, their wishes were to wait until they could be fitted with a new PTB. We anticipate that by the time that they are ready for a new prosthesis, they will want to stay with the PTS fitting.
It was completely and flatly rejected by only three cases, two of those during the dynamic alignment period. One of the two went back to a conventional below-knee prosthesis and with the other one, the proximal trim lines were cut to those of a PTB and dynamic alignment completed. The other patient could not tolerate total weight bearing on the stump after a few months, and in this case the brim was cut to allow for the addition of side joints and thigh lacer, resulting in a satisfactory prosthesis.
Six of the eleven cases wore the PTS for short periods of time and decided that they preferred the PTB, with which they had been quite happy previously. In four of these six cases, the PTS trim lines were cut to the level of PTB trim lines with no adverse effect to the alignment of the prosthesis, and a satisfactory PTB fit was maintained. In the other two, realignment of the prosthesis was necessary, and with one of the two a new socket was necessary, leaving speculation as to the fit of the socket as a PTS. None of these six people actually rejected the PTS, but their preference was the PTB.
The most consistent reason for PTB preference (six patients) was that the PTS was larger around the knee and with today's tight trousers, it caused more bulk inside the trousers. Two others had trouble kneeling. It should be recognized though, that all of these people had worn the PTB for some considerable length of time and were very happy with it.
One patient was discontinued from any prosthesis by her physician, due to her medical condition.
Five patients were rated as "Questionable" and with most of these we feel that they would probably be rated the same in any type of prosthesis.
Eighty of the ninety-seven are rated as Satisfactory and Very Satisfactory. Naturally, a number of these might well have been rated the same in other types of prostheses also. But we do want to point out that there are a number of these with short stumps, unstable knee joints, etc., that we would not have even attempted to fit with the classic PTB. Acceptance by these patients ran very high in cosmesis, function, and comfort, and many felt that this was by far the finest type of prosthetic fitting they have ever had.
We naturally wish now that comparative statistics had been kept on patients fitted with other types of below-knee prostheses during the same period of time, so that more complete comparisons could be made.
Eight of the definitive PTS Prostheses in this study were hard sockets with foam ends, while the remainder had soft (UCB type) inserts.
We do not intend this paper to take anything away from the PTB or other types of below-knee prostheses, but merely show, statistically, that the PTS has had extensive clinical application and that it is another type of socket modification that the prosthetist has available to fit some of the many below-knee amputation problems he is faced with daily. It has proven to be highly acceptable to most amputees. We have seen some problem stumps fitted successfully with it when we could not do so with other types of prostheses. Physicians who have had experience with the PTS have accepted it highly. We feel that any prosthetist, who is skilled in PTB fitting can, following Nitschke and Marschall instructions and applying his own ability and experience, satisfactorily fit the PTS.
We feel that the PTS Prosthetic Fitting is "here to stay" and should be another consideration when a patient is being evaluated for a prosthetic prescription.