BACKGROUND AND OBJECTIVES

Mouth retractors are essential in ensuring efficient yet safe exposure of the oral cavity and oropharynx. However, when applied improperly or haphazardly, retractors can cause tissue injuries and compromise patient safety. In addition, there are gaps in the usability of existing designs. This study aimed to identify the issues encountered by otorhinolaryngology surgeons in the use of commercially available mouth retractors, design and fabricate an improved retractor, and explore the use of additive manufacturing (popularly known as 3D printing) for retractor prototyping.

The study used the United States Food and Drug Administration (US FDA) Design Control as its framework. End-user requirements from otorhinolaryngologists were collected through key informant interviews. Results were organized into a Design Input template which was used to guide the design and development process. Prototype designs were iteratively created using computer-aided design software and 3D printing. Once design specifications were satisfied, a beta prototype was fabricated and given to another cohort of otorhinolaryngologists. The participants assessed the usability of the beta prototype. System Usability Scale (SUS) was used to quantify participant's feedback.

Five designs were created in the course of the study. The final prototype was fabricated using a Stereolithography (SLA) 3D printer. Several features were developed to address user requirements. The primary modification was to make the retractor modular to facilitate easier and shorter mounting and assembly. Gingival injury was addressed with the replacement of the maxillary alveolus hook with support bars. Five participants evaluated the beta prototype which received a mean SUS score of 75, well above the 50th percentile threshold.

This study demonstrates the applicability of the US FDA Design Control Process in the local setting to improve the mouth retractor design. Clinical and ergonomic issues were identified and design solutions were proposed and some have been implemented in a low-fidelity prototype. Results of the small-scale usability test suggest that the present form factor can be the basis for further iterations. Future studies can implement the proposed features to address other clinical and ergonomic needs.

Prosthesis loosening is the leading cause of postoperative revision in unicompartmental knee arthroplasty (UKA). The deviation of medial and lateral translational installation of the prosthesis during surgery is a common clinical phenomenon and an important factor in increasing the risk of prosthesis loosening. This study established a UKA finite element model and a bone-prosthesis fixation interface micromotion prediction model. The predicted medial contact force and joint motion of the knee joint from a patient-specific lower extremity musculoskeletal multibody dynamics model of UKA were used as boundary conditions. The effects of 9 femoral component medial and lateral translational installation deviations on the Von Mises stress of the proximal tibia, the contact stress, and the micro-motion of the bone prosthesis fixation interface were quantitatively studied. It was found that compared with the neutral position (a/A of 0.492), the lateral translational deviation of the femoral component significantly increased the tibial Von Mises stress and the bone-prosthesis fixation interface contact stress. The maximum Von Mises stress and the maximum contact stress of the fixation interface increased by 14.08% and 143.15%, respectively, when a/A was 0.361. The medial translational deviation of the femoral component significantly increased the bone-prosthesis fixation interface micro-motion. The maximum value of micromotion under the conditions of femoral neutral and medial translation deviation was in the range of 20-50 μm, which is suitable for osseointegration. Therefore, based on considerations such as the micromotion range suitable for osseointegration reported in the literature, the risk of reducing prosthesis loosening, and factors that may induce pain, it is recommended that clinicians control the mounting position of the femoral component during surgery within the safe range of 0-4 mm medial translation deviation.
Humans ; Arthroplasty, Replacement, Knee/methods* ; Finite Element Analysis ; Biomechanical Phenomena ; Knee Prosthesis ; Tibia/surgery* ; Femur/surgery* ; Stress, Mechanical ; Prosthesis Failure ; Knee Joint/surgery* ; Prosthesis Design

Although metal blocks have been widely used for reconstructing uncontained tibial bone defects, the influence of their elastic modulus on the stability of tibial prosthesis fixation remains unclear. Based on this, a finite element model incorporating constrained condylar knee (CCK) prosthesis, tibia, and metal block was established. Considering the influence of the post-restraint structure of the prosthesis, the effects of variations in the elastic modulus of the block on the von Mises stress distribution in the tibia and the block, as well as on the micromotion at the bone-prosthesis fixation interface, were investigated. Results demonstrated that collision between the insert post and femoral prosthesis during tibial internal rotation increased tibial von Mises stress, significantly influencing the prediction of block elastic modulus variation. A decrease in the elastic modulus of the metal block resulted in increased von Mises stress in the proximal tibia, significantly reduced von Mises stress in the distal tibia, decreased von Mises stress of the block, and increased micromotion at the bone-prosthesis fixation interface. When the elastic modulus of the metal block fell below that of bone cement, inadequate block support substantially increased the risk of stress shielding in the distal tibia and fixation interface loosening. Therefore, this study recommends that biomechanical investigations of CCK prostheses must consider the post-constraint effect, and the elastic modulus of metal blocks for bone reconstruction should not be lower than 3 600 MPa.
Knee Prosthesis ; Humans ; Finite Element Analysis ; Tibia/surgery* ; Elastic Modulus ; Arthroplasty, Replacement, Knee/methods* ; Stress, Mechanical ; Metals ; Prosthesis Design ; Knee Joint/surgery* ; Biomechanical Phenomena

OBJECTIVE: To investigate the effectiveness of posterior lateral perforator flap in lower limb combined with free fibula for maxillary tissue defect repair. METHODS: Between December 2018 and December 2023, 16 patients with the maxillary malignant tumors were admitted. There were 10 males and 6 females, with an average age of 64.3 years (range, 54-75 years). There were 7 cases of maxillary gingival cancer, 5 cases of hard palate cancer, and 4 cases of maxillary sinus cancer. According to the 2017 American Joint Committee on Cancer (AJCC) TNM stage, there were 8 cases of stage Ⅲ, 6 cases of stage Ⅳa, and 2 cases of stage Ⅳb. After resection of the lesion, the remaining maxillary defects were classified into class Ⅱa in 3 cases, class Ⅱb in 5 cases, and class Ⅲb in 8 cases according to Brown's classification. The size of soft tissue defects ranged from 4 cm×3 cm to 8 cm×6 cm. The posterior lateral perforator flap in lower limb in size of 5 cm×4 cm-9 cm×7 cm were harvested to repair soft tissue defects, and free fibula in length of 6-11 cm were used to repair bone defects. The donor sites of the lower limb were sutured directly (6 cases) or repaired with free skin grafting (10 cases). Six patients with positive lymph node pathology were treated with radiotherapy after operation. At 6 and 12 months after operation, the self-assessment was performed by the University of Washington Quality of Survival Questionnaire Form (QUW-4) in five dimensions (facial appearance, swallowing function, chewing function, speech function, and mouth opening), and swallowing function was evaluated by using the Kubota water swallowing test. RESULTS: Postoperative pathological examination showed that all patients were squamous cell carcinoma. One patient who was treated with radiotherapy developed osteomyelitis and 1 patient developed venous crisis of skin flap. The rest of the flaps and all skin grafts survived, and the wounds healed by first intention. All patients were followed up 1-5 years (mean, 2.8 years). Two patients died of local recurrence of the tumor at the 4th and 5th years after operation, respectively. Except for the chewing function score and total score at 6 months after operation, which showed significant differences compared to preoperative scores ( P<0.05), there was no significant difference in other QUW-4 scale scores between different time points ( P>0.05). The patients' swallowing function evaluated by Kubota water swallowing test reached normal in 4 cases, suspicious in 9 cases, and abnormal in 3 cases at 6 months after operation, and 10, 6, and 0 cases at 12 months after operation, respectively. The swallowing function at 12 months was significantly better than that at 6 months ( Z=-2.382, P=0.017). CONCLUSION The posterior lateral perforator flap in the lower limb combined with free fibula to repair maxillary tissue defects can repair soft and hard tissue defects at the same time, so that the patient's facial appearance, swallowing function, chewing function, speech function, and mouth opening are satisfactorily restored and the mid-term effectiveness is good.
Humans ; Middle Aged ; Male ; Female ; Fibula/surgery* ; Aged ; Perforator Flap ; Plastic Surgery Procedures/methods* ; Maxilla/surgery* ; Maxillary Neoplasms/surgery* ; Free Tissue Flaps/transplantation* ; Lower Extremity/surgery* ; Bone Transplantation/methods* ; Treatment Outcome

OBJECTIVE: To investigate the effectiveness of digital three-dimensional (3D) printing osteotomy guide plate assisted total knee arthroplasty (TKA) in treatment of knee osteoarthritis (KOA) patients with femoral internal implants. METHODS: The clinical data of 55 KOA patients who met the selection criteria between July 2021 and October 2023 were retrospectively analyzed. Among them, 26 cases combined with femoral implants were treated with digital 3D printing osteotomy guide plate assisted TKA (guide plate group), and 29 cases were treated with conventional TKA (control group). There was no significant difference in gender, age, body mass index, side, Kellgren-Lawrence classification, preoperative visual analogue scale (VAS) score, Hospital for Special Surgery (HSS) knee score, knee range of motion, and other baseline data between the two groups ( P>0.05). The operation time, intraoperative blood loss, incision length, postoperative first ambulation time, surgical complications; VAS score, knee HSS score, knee range of motion before operation, at 1 week and 3 months after operation, and at last follow-up; distal femoral lateral angle, proximal tibial medial angle, hip-knee-ankle angle and other imaging indicators at last follow-up were recorded and compared between the two groups. RESULTS: The operation time, incision length, intraoperative blood loss, and postoperative first ambulation time in the guide plate group were significantly lower than those in the control group ( P<0.05). In the control group, there were 1 case of incision rupture and bleeding and 1 case of lower limb intermuscular venous thrombosis, which was cured after symptomatic treatment. There was no complication such as neurovascular injury, incision infection, or knee prosthesis loosening in both groups. Patients in both groups were followed up 12-26 months, with an average of 16.25 months. The VAS score, HSS score, and knee range of motion improved at each time point after operation in both groups, and further improved with time after operation, the differences were significant ( P<0.05). The above indicators in the guide plate group were significantly better than those in the control group at 1 week and 3 months after operation ( P<0.05), and there was no significant difference between the two groups at last follow-up ( P>0.05). At last follow-up, the distal femoral lateral angle, the proximal tibial medial angle, and the hip-knee-ankle angle in the guide plate group were significantly better than those in the control group ( P<0.05). CONCLUSION The application of digital 3D printing osteotomy guide plate assisted TKA in the treatment of KOA patients with femoral implants can simplify the surgical procedures, overcome limitations of conventional osteotomy guides, reduce surgical trauma, achieve individualized and precise osteotomy, and effectively restore lower limb alignment and knee joint function.
Humans ; Arthroplasty, Replacement, Knee/instrumentation* ; Osteoarthritis, Knee/surgery* ; Osteotomy/instrumentation* ; Male ; Retrospective Studies ; Female ; Printing, Three-Dimensional ; Femur/surgery* ; Middle Aged ; Bone Plates ; Range of Motion, Articular ; Aged ; Treatment Outcome ; Surgery, Computer-Assisted/methods* ; Knee Prosthesis ; Knee Joint/surgery* ; Operative Time

OBJECTIVE: To explore the feasibility of reconstruction of phonatory function by using a tubular free flap from upper-lateral upper arm to repair the laryngotracheal circumferential defect after near-total laryngectomy for laryngeal cancer. METHODS: A retrospective study was conducted on 7 patients who underwent near-total laryngectomy between June 2021 and October 2023, aged from 48 to 70 years (median, 59 years), 6 males and 1 female. The disease duration ranged from 1 to 11 months, with a median of 6 months. Pathological diagnosis of preoperative biopsy was squamous cell carcinoma. Tumor classification: glottic type in 5 cases, supraglottic type in 1 case, transglottic type in 1 case; TNM staging: T ₄N ₀M ₀ in 6 cases, T ₄N ₂M ₀ in 1 case; American Joint Committee on Cancer (AJCC) staging in 2017 was stage Ⅳ. Preoperative MRI angiography of upper arm was performed to investigate the blood supply in the upper and lateral regions of the upper arm. After near-total laryngectomy and bilateral neck lymph node dissection, the area of the laryngotracheal defect was measured. A free flap measuring 7.0 cm×5.0 cm to 8.0 cm×7.0 cm was harvested from the upper-lateral upper arm, rolled into a tube shape, and connected between the stump of the cervical trachea in the neck root and that of the epiglottis at the tongue base. Four patients received adjuvant radiochemotherapy, 1 patient received radiochemotherapy and targeted therapy, 2 patients adopted no further adjuvant treatment. RESULTS: All 7 patients were followed-up 1-2 years (mean, 1 year and 3 months). Four patients had primary wound healing, 2 patients had minor pharyngeal fistulas that healed after dressing change, 1 patient experienced pharyngeal fistula because of flap necrosis and the wound still healed without secondary surgery. All patients took food orally within 1 month after operation, and the tracheal cannula was retained. Six patients with survived flap gradually adapted to their new pronunciation mode and obtained satisfactory phonatory function from 15 days to 2 months after operation. Four patients had slight aspiration after operation. Till the end of the follow-up, all patients survived and no local recurrence or distant metastasis had been observed. The motor function of the upper arm was not affected, only partial sensory loss occurred in the area near the incision. The scar of the incision could be covered by the short sleeve so as to obtain a better aesthetic effect. CONCLUSION Using a tubular free flap from upper-lateral upper arm to repair the laryngotracheal circumferential defect after near-total laryngectomy for laryngeal cancer can achieve satisfactory phonatory restoration while preserve the motor function and aesthetics of the donor site.
Humans ; Laryngectomy/methods* ; Male ; Middle Aged ; Female ; Laryngeal Neoplasms/surgery* ; Aged ; Free Tissue Flaps ; Retrospective Studies ; Plastic Surgery Procedures/methods* ; Carcinoma, Squamous Cell/surgery* ; Phonation ; Arm/surgery* ; Neck Dissection

OBJECTIVE: To review the latest research advancements in surgical techniques for the treatment of limb lymphedema. METHODS: The relevant literature at home and abroad in recent years was extensively reviewed, and the research on the treatment of limb lymphedema by surgical techniques were summarized and analyzed. RESULTS: Lymphovenous anastomosis has demonstrated good effectiveness for early to mid-stage limb lymphedema, however its long-term effectiveness and applicability for late-stage limb lymphedema still require further validation. Autologous lymphatic/venous grafting has shown clinical feasibility in the treatment of secondary limb lymphedema. Research on tissue-engineered lymphatic scaffolds remains insufficient, primarily due to the complexity of lymphatic anatomical structures and the technical challenges involved. Nevertheless, its potential application is promising. Vascularized lymph node flap transplantation has shown significant effectiveness in treating limb lymphedema, particularly yielding good outcomes in upper limb cases. However, it can not guarantee a complete cure for the condition. Charles' operation is the most effective treatment option for patients with late-stage limb lymphedema, but its extensive incision and severe postoperative complications limit its application. Liposuction has the advantages such as minimal invasiveness, high safety, and repeatability. It is suitable for patients with late-stage limb lymphedema who have failed conservative treatment or developed adiposity. However, its effectiveness is limited in patients with significant limb fibrosis. CONCLUSION Current treatments for limb lymphedema require further improvement, and there is considerable debate regarding treatment strategies for different stages of the condition. Future high-quality, multi-system combined treatment approaches are anticipated to guide clinical practice.
Humans ; Lymphedema/surgery* ; Surgical Flaps/blood supply* ; Lymphatic Vessels/surgery* ; Anastomosis, Surgical/methods* ; Lymph Nodes/transplantation* ; Lipectomy/methods* ; Extremities/surgery* ; Treatment Outcome ; Tissue Engineering ; Tissue Scaffolds ; Veins/transplantation*

OBJECTIVE: To investigate the effect of femoral condyle sliding osteotomy (FCSO) on the flexion gap and external rotation of the prosthesis in balancing coronal instability during initial total knee arthroplasty (TKA). METHODS: Between November 2021 and October 2024, FCSO technique was applied to balance the coronal medial and lateral spaces during initial TKA in 3 patients, including medial condyle sliding osteotomy (MCSO) and lateral condyle sliding osteotomy (LCSO). There were 1 male and 2 females with the age of 81, 68, and 68 years old. The affected knee has varus or valgus deformity, with tibia-femoral angles of 169.7°, 203.3°, and 162.2°, respectively. The hip-knee-ankle angle (HKA), range of motion (ROM), knee society scoring system (KSS), and pain visual analogue scale (VAS) score were used to evaluate joint function and pain relief. Based on model bone, the thickness and bone bed area of the medial and lateral femoral condyle osteotomy blocks in FCSO were measured. During TKA in 12 patients, the range of osteotomy block movement was evaluated. By simplifying the upward and forward movement of the osteotomy block into a geometric model, the impact of movement on the flexion gap and external rotation of the prosthesis was calculated. RESULTS: After application of FCSO during TKA, the limb alignment and medial and lateral balance at extension and flexion positions were restored in 3 patients. Three patients were followed up 23, 11, and 3 months, respectively. Postoperative HKA, pain VAS score, KSS score, and ROM all showed significant improvement compared to preoperative levels. The maximum thickness of osteotomy blocks by MCSO and LCSO was 17 and 12 mm, respectively. The simple upward movement of the osteotomy block mainly affected the extension gap, and had little effect on the flexion gap and external rotation of the prosthesis. Moving the osteotomy block forward at the same time had a significant impact on the flexion gap and external rotation of the prosthesis, especially on LCSO. Mild forward movement leaded to a decrease in external rotation of more than 3°, which had a serious impact on the patellar trajectory. CONCLUSION FCSO can effectively solve the problem of imbalance between the medial and lateral spaces during initial TKA, avoiding knee joint instability caused by excessive loosening and limiting the use of constrained condylar prosthesis. The distance for the downward movement of the osteotomy block in MCSO and LCSO was 3-5 mm and 6-8 mm, respectively, with 10-15 mm of space for forward movement and almost no space for backward movement. For MCSO, the upward and forward movement of the osteotomy block will increase the external rotation of the prosthesis, which is beneficial for improving the patellar trajectory and suitable for valgus knee. LCSO is suitable for varus knee, and the osteotomy block only slides vertically up and down without moving forward and backward.
Humans ; Osteotomy/methods* ; Male ; Female ; Arthroplasty, Replacement, Knee/methods* ; Aged ; Range of Motion, Articular ; Femur/surgery* ; Knee Joint/physiopathology* ; Aged, 80 and over ; Knee Prosthesis ; Treatment Outcome ; Osteoarthritis, Knee/surgery*

OBJECTIVE: To investigate the effectiveness of free latissimus dorsi myocutaneous flap transplantation combined with external fixation in the treatment of bone and soft tissue defects around the knee joint. METHODS: A retrospective analysis was conducted on the clinical data of 13 patients with high-energy trauma-induced bone and soft tissue defects around the knee joint admitted between January 2016 and July 2023. Among them, 11 were male and 2 were female, the age ranged from 23 to 61 years, with an average of 35.7 years. The causes of injury included 10 cases of traffic accident, 2 cases of machine entanglement injury, and 1 case of heavy object crush injury. According to the Gustilo-Anderson classification, 11 cases were type Ⅲ B and 2 cases were type Ⅲ C. Post-injury, 2 cases had wound infection and 2 cases had popliteal artery injury. The time from injury to flap repair was 40-49 days, with an average of 27.5 days. The wound size was 18 cm×13 cm to 32 cm×20 cm, all accompanied by distal femoral bone defects and quadriceps muscle defects. After primary debridement, vacuum sealing drainage combined with external fixation was used for treatment. In the second stage, free latissimus dorsi myocutaneous flaps were transplanted to repair soft tissue defects, with the flap size ranging from 20 cm×15 cm to 34 cm×22 cm. The donor sites of 9 flaps were directly sutured, and 4 cases with large tension were repaired with a keystone flap based on the posterior intercostal artery perforator. At 6-15 months postoperatively, with an average of 10.5 months, 11 patients underwent knee arthrodesis surgery; 2 patients with large bone defects at the distal femur and proximal tibia underwent multi-segment bone transport reconstruction of the bone defect. At last follow-up, the recovery of the flap and the donor site was recorded, and the function of the shoulder joint was evaluated by the American Shoulder and Elbow Surgeons (ASES) score, and the function of the affected knee joint was evaluated by the Knee Society Score (KSS). RESULTS: All the flaps survived after operation, the wounds and donor site incisions healed by first intention. All 13 patients were followed up 15-55 months, with an average of 21.6 months. Four patients who underwent the restoration of the donor site with the thoracodorsal keystone perforator flap had obvious scar hyperplasia around the wound, but no contracture or symmetrical breasts on both sides. At last follow-up, the appearance and texture of the flaps were good; the bony fusion of the knee joint was good, and the range of motion and function recovered well; the shoulder joint function on the flap-harvested side was not significantly affected, and the range of motion was satisfactory. The ASES shoulder joint score of the latissimus dorsi muscle-harvested side was 85-95, with an average of 89.5. The knee joint function KSS score was 75-90, with an average of 81.2. CONCLUSION Free latissimus dorsi myocutaneous flap transplantation combined with external fixation for the treatment of bone and soft tissue defects around the knee joint caused by high-energy trauma can repair bone and soft tissue defects and reconstruct the stability of the knee joint, effectively preserve the integrity of the limb and soft tissues, and improve the patient's ability of self-care.
Humans ; Male ; Female ; Adult ; Middle Aged ; Retrospective Studies ; Soft Tissue Injuries/surgery* ; Plastic Surgery Procedures/methods* ; Superficial Back Muscles/transplantation* ; External Fixators ; Myocutaneous Flap/transplantation* ; Knee Joint/surgery* ; Young Adult ; Treatment Outcome ; Knee Injuries/surgery* ; Free Tissue Flaps/transplantation*

OBJECTIVE: To analyze the effectiveness of single three-dimensional (3D)-printed microporous titanium prostheses and flap combined prostheses implantation in the treatment of large segmental infectious bone defects in limbs. METHODS: A retrospective analysis was conducted on the clinical data of 76 patients with large segmental infectious bone defects in limbs who were treated between January 2019 and February 2024 and met the selection criteria. Among them, 51 were male and 25 were female, with an age of (47.7±9.4) years. Of the 76 patients, 51 had no soft tissue defects (single prostheses group), while 25 had associated soft tissue defects (flap combined group). The single prostheses group included 28 cases of tibial bone defects, 11 cases of femoral defects, 5 cases of humeral defects, 4 cases of radial bone defects, and 3 cases of metacarpal, or carpal bone defects, with bone defect length ranging from 3.5 to 28.0 cm. The flap combined group included 3 cases of extensive dorsum of foot soft tissue defects combined with large segmental metatarsal bone defects, 19 cases of lower leg soft tissue defects combined with large segmental tibial bone defects, and 3 cases of hand and forearm soft tissue defects combined with metacarpal, carpal, or radial bone defects, with bone defect length ranging from 3.8 to 32.0 cm and soft tissue defect areas ranging from 8 cm×5 cm to 33 cm×10 cm. In the first stage, vancomycin-loaded bone cement was used to control infection, and flap repair was performed in the flap combined group. In the second stage, 3D-printed microporous titanium prostheses were implanted. Postoperative assessments were performed to evaluate infection control and bone integration, and pain release was evaluated using the visual analogue scale (VAS) score. RESULTS: All patients were followed up postoperatively, with an average follow-up time of (35.2±13.4) months. In the 61 lower limb injury patients, the time of standing, walk with crutches, and fully bear weight were (2.2±0.6), (3.9±1.1), and (5.4±1.1) months, respectively. The VAS score at 1 year postoperatively was significantly lower than preoperative one ( t=-10.678, P<0.001). At 1 year postoperatively, 69 patients (90.8%) showed no complication such as infection, fracture, prosthesis displacement, or breakage, and X-ray films indicated good integration at the prosthesis-bone interface. According to the Paley scoring system for the healing of infectious bone defects, the results were excellent in 37 cases, good in 29 cases, fair in 3 cases, and poor in 7 cases. In the single prostheses group, during the follow-up, there was 1 case each of femoral prostheses fracture, femoral infection, and tibial infection, with a treatment success rate of 94.1% (48/51). In lower limb injury patients, the time of fully bear weight was (5.0±1.0) months. In the flap combined group, during the follow-up, 1 case of tibial fixation prostheses screw fracture occurred, along with 2 cases of recurrent foot infection in diabetic patients and 1 case of tibial infection. The treatment success rate was 84.0% (21/25). The time of fully bear weight in lower limb injury patients was (5.8±1.2) months. The overall infection eradication rate for all patients was 93.4% (71/76). CONCLUSION The use of 3D-printed microporous titanium prostheses, either alone or in combination with flaps, for the treatment of large segmental infectious bone defects in the limbs results in good effectiveness with a low incidence of complications. It is a feasible strategy for the reconstruction of infectious bone defects.
Humans ; Male ; Female ; Middle Aged ; Printing, Three-Dimensional ; Titanium ; Retrospective Studies ; Surgical Flaps ; Adult ; Prosthesis Implantation/methods* ; Plastic Surgery Procedures/methods* ; Treatment Outcome ; Prostheses and Implants ; Bone Diseases, Infectious/surgery* ; Extremities/surgery* ; Prosthesis Design