Dislocation Of Prosthesis Research Articles

A New Malleostapedotomy Prosthesis. Experimental Analysis by Laser Doppler Vibrometer in Fresh Cadaver Temporal Bones

Introduction and objectivesOne of the problems with total ossicular replacement prostheses is their stability. Prosthesis dislocations and extrusions are common in middle ear surgery. This is due to variations in endo-tympanic pressure as well as design defects. The design of this new prosthesis reduces this problem by being joined directly to the malleus handle.The aim of this study is to confirm adequate acoustic-mechanical behaviour in fresh cadaver middle ear of a new total ossicular replacement prosthesis, designed using the finite elements method. MethodsUsing the doppler vibrometer laser, we analysed the acoustic-mechanical behaviour of a new total ossicular replacement prosthesis in the human middle ear using 10 temporal bones from fresh cadavers. ResultsThe transfer function of the ears in which we implanted the new prosthesis was superimposed over the non-manipulated ear. This suggests optimum acoustic-mechanical behaviour. ConclusionsThe titanium prosthesis analysed in this study demonstrated optimum acoustic-mechanical behaviour. Together with its ease of implantation and post-surgical stability, these factors make it a prosthesis to be kept in mind in ossicular reconstruction.

Incidencia de luxación de reemplazo de cadera con copas de doble movilidad (CDM) en pacientes con alto riesgo de inestabilidad

BackgroundThe incidence of dislocation of the total hip replacement (THR) is higher in patients with high risk of instability. The use of dual mobility cups (DMC) has a lower incidence of dislocation than conventional prostheses. Materials and methodsA retrospective cohort study was conducted on patients undergoing THR between 2011 and 2014 with DMC, and operated using the posterolateral approach by the same group of surgeons. The minimum follow-up was 6 months. The incidence of dislocation and the reason for deciding to use DMC was evaluated. Differences between groups were calculated using Fisher's exact test for qualitative variables, and the Wilcoxon test for continuous variables. ResultsThe study included 103 patients, with a mean age of 79.5 years, and with 73.7% women. The main reasons for using DMC were hip fracture (65%) and revision (31%). The incidence of prosthesis dislocation was 7.7%, with 87.5% of them occurring in women (P=.677). In patients with dislocation, 87.5% had fracture, and 63% had some cognitive impairment. DiscussionProsthetic dislocation remains as a problem, even with the use of the DMC in patients at high risk. The incidence of fractures and dislocation in revision surgery in our institution is similar to that reported in the literature. In our study, it was noted that dislocations mainly occurred in patients with fracture or with an alteration in mental state, which showed that this second factor was of great importance. Evidence levelIV. Observational study.

Early experience with lateral lumbar total disc replacement: Utility, complications and revision strategies

Lumbar total disc replacement (TDR) is an alternative to interbody fusion for the treatment of symptomatic degenerative disc disease. Traditionally, lumbar TDR is performed via an anterior retroperitoneal approach with regional risks of vascular and visceral injury. The direct lateral retroperitoneal, transpsoas approach avoids mobilisation of the great vessels and preserves the anterior longitudinal ligament, thereby maintaining physiological limits on motion. This study aimed to (i) report one site’s early experience with lateral lumbar TDR and (ii) provide case examples illustrating the utility, complications and revision strategies of the XL-TDR device. Data were collected prospectively on the first 12 consecutive patients treated with XL-TDR. Patient outcomes included pain (VAS), disability (ODI), and quality of life (SF-36 PCS and MCS). Mean follow-up was 27.5months (range 18–48months). Patients had significant improvements in back (74%) and leg (50%) pain, ODI (69%), PCS (50%) and MCS (39%) (P<0.05). Two patients had early prosthesis dislocation due to prosthesis undersizing. The same skin incision was used to retrieve the XL-TDR and perform salvage lateral lumber interbody fusion, with solid fusion by 12months. Lumbar TDR using the XL-TDR via a lateral transpsoas muscle-splitting approach is a minimally invasive alternative to anterior retroperitoneal exposures for motion preservation. Correct sizing of the XL-TDR and complete contralateral annulectomy with annulus box cutters mitigates the risk of lateral dislocation. Revision surgery for lateral dislocation of the XL-TDR is more straightforward compared to anterior TDR dislocation.

Acute pulmonary hemorrhage after dislocation of transcatheter aortic valve prosthesis.

Acute pulmonary hemorrhage after dislocation of transcatheter aortic valve prosthesis.

Application of jumbo cup in acetabular revisions for patients with massive acetabular bone deficiency

Objective To investigate the effects of the jumbo cup in acetabular revision for patients with massive acetabular bone deficiency. Methods We retrospectively studies 48 patients (49 hips) who underwent jumbo cup revisions between 2006 and 2015 (19 men and 29 women; average age: 62±12 years). The acetabular bone defects were classified according to Paprosky classification (Paprosky II 27 hips, Paprosky IIIA 18 hips, Paprosky IIIB 4 hips). Radiological assessments were conduced to evaluate the acetabular prosthesis loosening, dislocation and infection. The reasons for revisions were mechanical loosening in 41 cases, and infections in another 8 cases with cement spacer putted by last surgery. Results The operation duration and blood loss was 110 min (85-160 min) and 315 ml (270-455 ml) respectively. After an average follow-up of 6.8 years (1-11 years), Harris hip score was increased from 47.6 ± 7.1 preoperatively to 82.4 ± 6.2 postoperatively. Osseointegration occurred in the acetabular components at 6 months postoperatively. Radiograph analysis showed satisfied position of acetabular cup without complications such as damages of vessels or nerves. The successful rate of jumbo cup revisions was 89.8%±4.4%. However, two in Paprosky IIIA failures for periprosthetic infection occurred and two in Paprosky IIIA, one in Paprosky IIIA and the other in Paprosky IIIB for acetabular component loosening. One patient in Paprosky IIIB had weight-bearing pain and relieve slightly after conservative treatment. The radiologic study showed that there was no relationship between failure rate and acetabular abduction angle (r=0.06, P= 0.53), rotation center migration in vertical direction (r=0.11, P=0.14) and horizontal direction (r=0.04, P=0.89). Conclusion The mid-term results show that using jumbo cup in revising acetabular failure with massive bone deficiency are optimal, which can be achieved by simplified operation procedures, reduction in the need of bone graft and promotion in acetabulum osseointegration. However, higher failure rate may occur in Paprosky IIIB patients. Key words: Arthroplasty, replacement, hip; Reoperation; Acetabulum; Osteolysis; Prosthesis failure

Clinical results of arthroscopic suture for meniscal tear in middle aged adults

To study the characteristics and clinical effect of total hip arthroplasty(THA) for osteoarthritis and (or) avascular necrosis of femoral head after failure of internal fixation of acetabular fracture. From February 2009 to October 2014, 31 patients (31 hips) with hip traumatic osteoarthritis and (or) femoral head avascular necrosis after failure of internal fixation of acetabular fracture were treated with THA including 26 males and 5 females, who injured when the average age of(41±12) years. THA were performed, and the duration ranged from 3 to 132 months with a mean of(20.6±26.9) months secondary to traumatic osteoarthritis and(or) femoral head avascular necrosis. All THA were performed with posterior-lateral approach. The postoperative complications were observed. VAS and Harris hip scores were compared pre-operation and post-operation. Twenty-seven cases were followed up, and the duration ranged from 12 to 80 months with a mean of (43.2±11.7) months. One patient had infection around prosthesis. Aseptic loosening occurred in 1 patient, dislocation of prosthesis in 1 patient. No sciatic nerve injury occurred. Hip function and gaits were obviously improved. To the last follow-up, VAS score was decreased from 7.6±1.2 pre-operatively to 1.2±0.9 post-operatively, while the Harris score was improved from 45.5±13.6 pre-operatively to 88.5±7.8 post-operatively, both differences were statistically significant(P<0.01). The post-operative ROM of hip was significantly improved compared to pre-operative ROM(P<0.05), in addition to extension motion. X-ray showed all the acetabular cups were stable, one femur stem subsided 3 mm. Heterotopic ossification occurred in 2 cases. Correct dealing with of internal fixation implants, looking out potential infection and reasonable reconstruction of acetabular bone deficiency were the key to the success of THA for osteoarthritis and(or) avascular necrosis of femoral head after failure of internal fixation of acetabular fracture.

Les complications et échecs de la prothèse trapézo-métacarpienne Maiay : à propos de 156 prothèses

When implanting the Maiay trapeziometacarpal prosthesis, surgeons will be faced with a variety of complications they must be able to recognise and anticipate. Their ability to deal with these complications and possibly even failures are governed by their knowledge of the right steps to take. The aim of this retrospective study was to assess the incidence of complications reported during implantation of the Maiay prothesis, describe their nature and potential predisposing factors, and to study failures and their outcomes. Between January 2008 and December 2012, 156 Maiay prosthetic joints were implanted in 139 patients at one centre per surgeon. Clinical and radiological parameters were analysed before, during and after surgery. The characteristics of the implant were studied and the surgical technique used analysed. The overall postoperative complications rate was 35.9%. The most common complication (16%) was tendinopathy. Prosthesis dislocation (4.5%) and trapezoid loosening (2.6%) were the primary causes of failure. Eighteen patients required secondary surgical revision (11.5%) and the implant was removed in 12 cases (failure rate of 7.7%). Two factors were significantly correlated with the onset of complications, whatever their nature and irrespective of whether secondary surgical revision was required, a deformed thumb prior to surgery and the position of the trapezium cup. Mediocre trapezium bone quality was a statistically significant factor for secondary surgical revision. These factors influence the onset of complications and must be taken into account in the pre-surgical workup in order to identify the best candidates for successful Maiay joint replacement. For the main part, the failure rate in our series was due to inappropriate surgical technique rather than an inherent defect in the prosthesis. A meticulous and precise surgical technique is therefore essential.

Implant Migration in Cervical Disk Arthroplasty

The purpose of this study is to discuss the causes of implant migration after cervical arthroplasty with clinical cases. The patients who underwent cervical arthroplasty operations in our department between 2006 and 2015 because of cervical disk disease were retrospectively analyzed. The patients who were determined to be symptomatic of implant migration were evaluated. Symptomatic implant migration was detected in 5 of 163 (0.3%) patients who underwent cervical disk arthroplasty, and these patients also underwent reoperation. In 4 patients who underwent reoperation, the prosthesis was removed, and an anterior fusion was made. The prosthesis was only removed in 1 patient. The following situations should be considered in the prevention of dislocation and migration of the implant in cervical arthroplasty: protection of the structure of the end plate, selection of the appropriate implant size, and proper surgical construction. In the preoperative period, computed tomography scan may be useful for determining the implant size and details of the bone structure. Foreign body reactions or postoperative trauma may be a rare and unpreventable reason for prosthesis dislocation despite all of the preoperative and perioperative measures and well-made prosthesis designs.

P17 Dislocation of knee prosthesis and treatment with Osteobridge (TM) arthrodesis system

P17 Dislocation of knee prosthesis and treatment with Osteobridge (TM) arthrodesis system

Surgical delay as a risk factor for wound infection after a hip fracture

Analysis of significant risk factors for mortality and for medical and orthopaedic complications. Observational study of a prospective consecutive cohort of 697 patients diagnosed of hip fracture from December 2012 to December 2014. Average age was 85±9years and 520 were female (75%). Intracapsular fractures (308, 44%) were treated non-operatively, (19 patients), with cannulated screws (58) or with hip arthroplasty (228 bipolar, 3 total hip atrhoplasty). Extracapsular fractures (389, 56%) were reduced and fixed with 375 trochanteric nails and 14 sliding-hip-screw-plates. Patients were controlled clinically and radiographically in outpatient clinic after 1, 3, 6 and 12months. Bivariate analysis (Pearson, Mann-Whitney, Wilcoxon) was applied to study statistically significant relations, and Odds Ratio were calculated. Surgical delay reached 2.1±2.2days, 1.7±1.9 in medically stable patients. Main reason for delay was anticoagulant/anti-platelet therapy. Immediate weight-bearing was begun for 72% of patients. Average time in-hospital was 12±8days and 63% returned to previous environment. Lost-to-follow-up reached 4% after 1month and 8% after 6months. After 1year, 6% of previously-walking patients were unable to walk. Mortality reached 4% while in-hospital and 14% after 1year, with older age as only significant risk factor (p=0.004), OR=1.9. Wound infection developed in 2.3% of the series, and surgical delay longer than 24hours was a significant risk factor (p=0.023), with an OR=3.48 (1.1-10.8). Fixation failed in 7.9% of cannulated screws and 1.9% of trochanteric nails (1.1% cut-out, 0.8% nail fracture), while 2.7% of arthroplasty patients suffered a prosthesis dislocation and 1.3% a periprosthetic fracture. Pyelonephritis appeared in 6.7%, pneumonia in 6.3% and cardiac failure in 2.2% of patients; significant risk factors were previous comorbidity for pneumonia (p=0.007) (OR=2.7) and cardiac failure (p=0.007) (OR=9.7), as well as older age (p=0.006) (OR=2.2) for pneumonia. Surgical delay longer than 24hours has been an important risk factor for wound infection, a finding not previously described in literature. Older age is a significant risk factor for mortality and pneumonia, and previous comorbidity for cardiac failure and pneumonia.

Primary shoulder arthroplasty using a custom-made hip-inspired implant for the treatment of advanced glenohumeral arthritis in the presence of severe glenoid bone loss

Total shoulder arthroplasty for end-stage glenohumeral arthritis with severe glenoid bone loss poses a unique challenge for shoulder surgeons. Current surgical solutions are limited and associated with high complication rates. We hypothesized that a custom-made computer-aided design-computer-aided manufacturing (CAD-CAM) total shoulder replacement (TSR; Stanmore Implants Worldwide, Elstree, UK) resembling a total hip prosthesis could offer a reliable alternative for this challenging subset of patients. Thirty-seven patients with rotator cuff-deficient end-stage glenohumeral arthritis and severe glenoid bone loss (assessed as not amenable to treatment with standard anatomic or reverse total shoulder implants) were treated with the CAD-CAM TSR between 2006 and 2013. Clinical data were collected prospectively and analyzed at a mean follow-up of 5 years. Postoperatively, the pain level with activity decreased from 9.2 ± 1.7 to 2.4 ± 2.9 (P < .001). The Oxford Shoulder Score improved from 11 ± 8 points to 27 ± 11 points (P < .001), and the Subjective Shoulder Value (on a 0%-100% scale) improved from 23% ± 14% to 60% ± 24% (P < .001). Active forward elevation improved from 39° ± 23° to 63° ± 38° (P < .001), and external rotation improved from 6° ± 16° to 15° ± 17° (P = .001). Component revision was required in 6 of 37 patients (16%) (glenoid loosening in 1, humeral stem loosening in 3, periprosthetic fracture in 1, and prosthesis dislocation in 1). The CAD-CAM TSR offers a reliable alternative for the treatment of end-stage glenohumeral arthritis with severe glenoid deficiency not amenable to standard anatomic or reverse total shoulder implants, with maintenance of significant pain relief and clinical-functional improvement at 5-year postoperative follow-up.

Collagen-conjugated tracheal prosthesis tested in dogs without omental wrapping and silicone stenting.

Artificial tracheas fabricated from collagen-conjugated mesh appear to overcome fatal postoperative complications, namely anastomotic dehiscence and prosthesis dislocation. Such prostheses are incorporated by host tissue, provided they are wrapped in omentum (necessitating an additional abdominal procedure) and a silicone tube is used as a stent (to be extracted several weeks postoperatively). To mitigate related host impact (i.e. injury, pain and distress), we investigated the feasibility of implanting this type of tracheal prosthesis (∼5 cm in length) alone, without omental wrapping and use of a silicone stent. Porous-type tracheal prostheses that were reinforced with a continuous polypropylene spiral and sealed by collagen sponge from porcine skin replaced segments of cervical trachea (∼5 cm long) in 10 dogs through the method of telescopic anastomosis. Omental wrapping and silicone stent placement were omitted. Postoperatively, bronchoscopic examination was performed periodically. When dogs died or were sacrificed, tracheal prostheses were harvested for haematoxylin and eosin staining and electron microscopic scanning of luminal surface conditions. With the exception of one death from an anaesthesia-related incident during fibre-optic bronchoscopy (postsurgical week 1), nine dogs survived uneventfully (until sacrifice), without prosthesis dislocation or anastomotic dehiscence. The longest observation period was 2 years and 8 months. Bronchoscopic examination revealed that no stenosis or local infection was evident in the prostheses of five dogs. Moderate (n = 2) and slight (n = 2) stenoses were observed in the other four animals. All four animals survived for a long time, without dyspnoea or stridor. Histological examination showed that partial inner surface of the artificial trachea was covered with the pseudostratified ciliated epithelium. Regeneration of ciliated epithelium was also confirmed by scanning electron microscopy. This pilot study revealed that implantation of a collagen-conjugated tracheal prosthesis (∼5 cm in length) is feasible without the need for omental wrapping and silicone stenting as ancillary measures. This approach considerably simplified the surgical procedures to minimize host intrusion, which indicated a possible clinical application.

Assistive devices, hip precautions, environmental modifications and training to prevent dislocation and improve function after hip arthroplasty.

Assistive devices, hip precautions, environmental modifications and training to prevent dislocation and improve function after hip arthroplasty.

Measurement of quality of life among patient undergoing arthroplasty of the thumb to treat CMC arthritis

ObjectiveTo present the clinical and functional results, including measurement of quality of life, of patients undergoing trapeziometacarpal arthroplasty. MethodThis was a prospective evaluation on 45 patients (53 thumbs) with a diagnosis of idiopathic rhizarthrosis who underwent resection arthroplasty and interposition of an uncemented Ascension® implant, made of pyrocarbon. The clinical and functional results were analyzed through radiography, range of motion (ROM) in degrees (°), visual analog scale (VAS) for pain and the disability of arm, shoulder and hand (DASH) questionnaire for quality of life. In the group analyzed, 38 were women and seven were men, and their mean age was 63.17 years (range: 50–78). Eight patients were treated bilaterally. ResultsAfter 42.08 months of follow-up (range: 8–73), the subjective pain evaluation (VAS) score was 1.37 (range: 1–4). The complete ROM of the thumb increased to 95.75% (range: 75–100%) in relation to the contralateral side. The mean DASH questionnaire score was 9.98 (range: 1–18). The complication rate (negative events) was 11.32%. Five patients presented dislocation of the thumb prosthesis. All of them were reoperated by means of dorsal capsuloplasty using a portion of the retinaculum of the extensors as a graft, and good clinical evolution was achieved in these cases. One patient presented fracturing of the metacarpal and was treated by means of osteosynthesis using Kirschner wires. ConclusionThis method is effective for treating rhizarthrosis, according to the measurements made on the clinical and functional results, even after taking the complication rate into consideration. Moreover, it provides an improvement of quality of life for these patients.

Complications and failures of the trapeziometacarpal Maia® prosthesis: A series of 156 cases

When implanting the Maia® trapeziometacarpal prosthesis, surgeons will be faced with a variety of complications they must be able to recognize and anticipate. Their ability to deal with these complications and possibly even failures is governed by their knowledge of the right steps to take. The aim of this retrospective study was to assess the incidence of complications reported during implantation of the Maia® prosthesis, to describe their nature and potential predisposing factors, and to study failures and their outcomes. Between January 2008 and December 2012, 156 Maia® prosthetic joints were implanted in 139 patients at one center by one surgeon. Clinical and radiological parameters were analyzed before, during and after surgery. The implant characteristics were documented and the surgical technique used was analyzed. The overall postoperative complication rate was 35.9%. The most common complication (16%) was tendinopathy. Prosthesis dislocation (4.5%) and trapezoid loosening (2.6%) were the primary causes of failure. Eighteen patients required secondary surgical revision (11.5%) and the implant was removed in 12 cases (failure rate of 7.7%). Two factors were significantly correlated with the onset of complications, independent of their nature and irrespective of whether secondary surgical revision was required: a deformed thumb prior to surgery and the position of the trapezial cup. Mediocre trapezium bone quality was a statistically significant factor for secondary surgical revision. The survival rate of the Maia® prosthesis was 90.8% at 62months. These factors influence the onset of complications and must be taken into account in the pre-surgical workup in order to identify the best candidates for successful Maia® joint replacement. For the most part, the failure rate in our series was due to inappropriate surgical technique rather than an inherent defect in the prosthesis. A meticulous, precise surgical technique is therefore essential.

Análisis experimental mediante vibrometría láser doppler en huesos temporales de cadáver fresco de una nueva prótesis de maleovestibulopexia

Introduction and objectivesOne of the problems with total ossicular replacement prostheses is their stability. Prosthesis dislocations and extrusions are common in middle ear surgery. This is due to variations in endo-tympanic pressure as well as design defects. The design of this new prosthesis reduces this problem by being joined directly to the malleus handle.The aim of this study is to confirm adequate acoustic-mechanical behaviour in fresh cadaver middle ear of a new total ossicular replacement prosthesis, designed using the finite elements method. MethodsUsing the doppler vibrometer laser, we analysed the acoustic-mechanical behaviour of a new total ossicular replacement prosthesis in the human middle ear using 10 temporal bones from fresh cadavers. ResultsThe transfer function of the ears in which we implanted the new prosthesis was superimposed over the non-manipulated ear. This suggests optimum acoustic-mechanical behaviour. ConclusionsThe titanium prosthesis analysed in this study demonstrated optimum acoustic-mechanical behaviour. Together with its ease of implantation and post-surgical stability, these factors make it a prosthesis to be kept in mind in ossicular reconstruction.

Application of extended nursing in rehabilitation of elderly patients after hip arthroplasty

Objective To investigate the effect of extended nursing care in the rehabilitation of elderly patients with hip arthroplasty. Methods From January 2014 to June 2014, 250 patients who underwent hip arthroplasty in our hospital were selected and divided into observation group and control group by random digits table. There were 125 cases in each group. Patients in control group received conventional nursing and observation group received additional extended nursing, which contained rehabilitation manuals, health records, rehabilitation guiding out of hospital by the extended care team, and established patients communication group. The hip joint function(Harris Hip score), life quality(Barthel index) and postoperative complications were compared between two groups. Results The average score of Harris hip function in 6 months and 1 year post-operative in observation group were (92.3±2.4) and (95.8±2.8), respectively, which were significantly higher than (85.3±2.9) and (92.1±3.5) in the control group(P<0.05). The average score of Barthel index in 6 months and 1 year post-operative in observation group were (90.6±2.5) and (94.5±3.2), respectively, which were significantly higher than (83.5±3.6) and (91.2±3.8) in the control group(P<0.05). The incidence of prosthesis dislocation, deep venous thrombosis of lower limb and pressure ulcer in observation group was significantly lower than that in the control group(P<0.05). Conclusions Extended care can improve the rehabilitation effect of elderly patients with hip arthroplasty, it can improve the hip function and the activities of daily living, and reduce complications. Key words: Elderly; Hip arthroplasty; Rehabilitation; Extended nursing

Mensuração da qualidade de vida dos pacientes submetidos a artroplastia do polegar no tratamento da rizartrose

ObjectiveTo present the clinical and functional results, including measurement of quality of life, of patients undergoing trapeziometacarpal arthroplasty. MethodThis was a prospective evaluation on 45 patients (53 thumbs) with a diagnosis of idiopathic rhizarthrosis who underwent resection arthroplasty and interposition of an uncemented Ascension® implant, made of pyrocarbon. The clinical and functional results were analyzed through radiography, range of motion (ROM) in degrees (°), visual analogue scale (VAS) for pain and the disability of arm, shoulder and hand (DASH) questionnaire for quality of life. In the group analyzed, 38 were women and seven were men, and their mean age was 63.17 years (range: 50‐78). Eight patients were treated bilaterally. ResultsAfter 42.08 months of follow‐up (range: 8‐73), the subjective pain evaluation (VAS) score was 1.37 (range: 1‐4). The complete ROM of the thumb increased to 95.75% (range: 75‐100%) in relation to the contralateral side. The mean DASH questionnaire score was 9.98 (range: 1‐18). The complication rate (negative events) was 11.32%. Five patients presented dislocation of the thumb prosthesis. All of them were reoperated by means of dorsal capsuloplasty using a portion of the retinaculum of the extensors as a graft, and good clinical evolution was achieved in these cases. One patient presented fracturing of the metacarpal and was treated by means of osteosynthesis using Kirschner wires. ConclusionThis method is effective for treating rhizarthrosis, according to the measurements made on the clinical and functional results, even after taking the complication rate into consideration. Moreover, it provides an improvement of quality of life for these patients.

Short-term outcomes analysis of anatomical resurfacing artificial joint replacement in the treatment of joint diseases in the hand

Objective To investigate the clinical outcomes of applying the anatomical resurfacing implant in treating joint diseases and improving hand function. Methods A total of 15 cases with proximal interphalangeal (PIP) joint or metacarpophalangeal (MP) joint diseases were treated with arthroplasty and resurfacing artificial joint replacement from April 2013 to March 2014. There were 2 patients with primary osteoarthritis, 2 patients with rheumatoid arthritis and 11 patients with post-traumatic arthritis. Pre and postoperative pain was evaluated by the visual analogue scale (VAS). Grip strength, active range of motion of the joints and DASH scores were measured as well to assess the treatment outcomes. Results Primary wound healing was achieved in all the patients. Postoperative follow-up period ranged from 12 to 20 months, with an average of 14.5 months. Pain was significantly alleviated from a 6.3 VAS score preoperatively to a 1.5 score at the latest follow-up (P 0.05). PIP joint active range of motion increased from (30.0±11.2)° preoperatively to (45.2±14.8)° at last follow-up, the difference being statistically significant (P 0.05). The mean DASH score decreased from 46.3±9.6 to 30.9±11.6. The improvement was statistically significant (P< 0.05). Implant dislocation was seen in one PIP joint in the middle finger and one MP joint in the thumb. No other complications such as implant rupture, peri-implant fracture or infections were noted. Conclusion The anatomical resurfacing artificial joint replacement is effective in treating joint stiffness, joint deformity and joint pain. The short-term results are satisfactory. Surgical approach and management of surrounding scarring tissues are subject to further investigation. Key words: Joint prosthesis; Treatment outcome; Surface replacement; Prosthesis dislocation

Surgical results of cranioplasty with a polymethylmethacrylate customized cranial implant in pediatric patients: a single-center experience.

OBJECTIVE Cranioplasty is a reconstructive procedure used to restore skull anatomy and repair skull defects. Optimal skull reconstruction is a challenge for neurosurgeons, and the strategy used to achieve the best result remains a topic of debate, especially in pediatric patients for whom the continuing skull growth makes the choice of material more difficult. When the native bone flap, which is universally accepted as the preferred option in pediatric patients, is unavailable, the authors' choice of prosthetic material is a polymethylmethacrylate (PMMA) implant designed using a custom-made technique. In this paper the authors present the results of their clinical series of 12 custom-made PMMA implants in pediatric patients. METHODS A retrospective study of the patients who had undergone cranioplasty at Gaslini Children's Hospital between 2006 and 2013 was conducted. A total of 12 consecutive cranioplasties in 12 patients was reviewed, in which a patient-specific PMMA implant was manufactured using a virtual 3D model and then transformed into a physical model using selective laser sintering or 3D printing. All patients or parents were administered a questionnaire to assess how the patient/parent judged the aesthetic result. RESULTS Patient age at craniectomy ranged from 5 months to 12.5 years, with a mean age of 84.33 months at cranioplasty. The mean extension of the custom-made plastic was 56.83 cm(2). The mean time between craniectomy and cranioplasty was 9.25 months. The mean follow-up duration was 55.7 months. No major complications were recorded; 3 patients experienced minor/moderate complications (prosthesis dislocation, granuloma formation, and fluid collection). CONCLUSIONS In this patient series, PMMA resulted in an extremely low complication rate and the custom-made technique was associated with an excellent grade of patient or parent satisfaction on long-term follow up.