## 4 Discussion
### Prosthetic Supply, Assistive Devices, and Mobility  
All responding amputees were fitted with a prosthesis. Almost all amputees (N = 26) needed one further assistive device in addition to their prosthesis. The additional need for assistive devices could be due to the overall rather low level of mobility. Other studies reported comparable dependency on further assistive devices to achieve independence and safety in everyday life locomotion [23]. Those results affirm the importance of the supply beyond the prosthetic device. The association between prosthetic use and physical activity is an important subject to discuss [24]. Herein, 55% (N = 15) of the amputees used their prosthesis up to eight hours a day and 8% (N = 2) did not use the prosthesis at all. Other investigations report that 40% of patients used their prosthesis between 6 and 16 h a day [23] and less than 20% of the study participants did not use prosthetic provision at all, or only rarely [25]. Even though the overall mobility of both patient groups decreased after the amputation, the regained mobility in trauma patients was higher. Although four out of seven patients had reached a mobility level of K2 after amputation, none dropped below that level. In contrast, four patients (20%) with a nontraumatic cause of amputation were no longer able to walk at all after the amputation (K-level 0), most probably limited by their accompanying comorbidities and age. Therefore, mobility post-amputation is mainly related to, or even determined by, mobility prior to amputation, and this implies accompanying underlying systemic disease [26; 27]. Thus, those determining factors should be identified, and other medical disciplines, such as internal medicine, should be involved in amputation care to address the underlying pathologies limiting mobility. Furthermore, concepts described as prehabilitation might be integrated in an amputee care concept. The term prehabilitation describes all interventions aiming to improve a person's functional capacity, as well as tolerance to possible future physiological stress, such as surgical interventions [28]. Prehabiliation has not yet been a focus of research regarding major lower-limb amputation [19]. The finding that there was no relationship between the final K-level and the time that passed until prosthetic fitting was quite unexpected. We expected a strong correlation between a high K-level and shorter time until prosthetic supply, since reports in the literature have shown that earlier prosthetic fitting can lead to quicker ambulation and walking ability [29; 30]. Again, this study lacks a time-based analysis of the measured parameters, especially mobility outcome parameters, which can change over time during rehabilitation. Relations of Quality of Life, Adaption to the New Life Situation, Mobility, and Satisfaction with the Assistive Devices (QUEST)  
Even though we found that self-rated QoL was mostly reported to be severely limited due to the amputation, the self-rated adaptation to the new situation was mostly satisfactory in the analyzed cohort (largely adapted, 74%, N = 27). The correlation analysis revealed overall high satisfaction for both traumatic and nontraumatic patients with the devices and service, indicating higher adaptation to the new situation if good service and satisfying assistive devices were received. The correlation analysis for QoL correlated negatively with K-level, adaptation to the new life situation, and satisfaction with the device and services. Within this study, for amputees with AKA and knee disarticulations, impact on QoL was not relevant when compared to amputees at more distal amputation levels. This is congruent to other studies showing no correlation between satisfaction measured by the QUEST questionnaire and amputation levels [31]. Due to the limited number of study participants, it was not possible to discern possible reasons.