Accuracy of two-dimensional digital planning in uncemented primary hip arthroplasty: monocentric analysis of eight hundred implants.

PURPOSE: In the last decades, there has been a refinement in total hip arthroplasty, which allowed surgeons to achieve the highest performance and better patient outcomes. Preoperative planning in primary hip arthroplasty is an essential step that guides the surgeon in restoring the anatomy and biomechanics of the joint. This study aims to evaluate the accuracy of the 2D digital planning, considering cup sizing, stem sizing, and limb length discrepancy. Additionally, we conducted a multivariable analysis of demographic data and comorbidities to find factors influencing preoperative planning. METHODS: This retrospective study analyzed the planning accuracy in 800 consecutive uncemented primary total hip arthroplasty. We compared the preoperatively planned total hip arthroplasty with postoperative results regarding the planned component size, the implanted size, and the lower limb length restoration. Therefore, we investigated factors influencing planning accuracy: overweight and obesity, sex, age, past medical history, comorbidities, and implant design. All the surgeries were performed in the posterolateral approach by one expert surgeon who did the preoperative planning. The preoperative planning was determined to be (a) exact if the planned and the implanted components were the same size and (b) accurate if exact ± one size. The restoration of postoperative limb length discrepancy was classified into three groups: ± 3 mm, ± 5 mm, and ± 10 mm. This assessment was performed through a digital method 2D based on a standard hip X-ray. RESULTS: This court of 800 implants showed that planning was exact in 60% of the cups and 44% of the stems and was accurate in 94% of the cups and 80% of the stems. The postoperative limb length discrepancy was ± 3 mm in 91% and ± 5 mm in 97%. CONCLUSIONS: This study showed preoperative 2D digital planning great precision and reliability, and we demonstrated that it was accurate in 94% of the cups and 80% of the stems. Therefore, the preoperative limb length discrepancy analysis was essential to guarantee the recovery of the operated limb's correct length.

A new classification for proximal femur bone defects in conservative hip arthroplasty revisions.

INTRODUCTION: In last three decades, total hip replacement in young patients became an habitual procedure. Principles of bone preservation are pushing many surgeons to implant conservative femoral components in patient younger than 65 years. Despite an overall good survivorship and clinical outcomes of conservative implants, failed cases are reported and the need to revise a conservative femoral component became an occasional procedure (with high prevalence of failed resurfacing implants). METHODS: During conservative femoral component revisions, we analyzed proximal bone stock preservation, considering the type of original component removed, aetiology of failure, timing of revision, and femoral explantation technique. RESULTS: We identified four patterns of proximal femoral changes (types I-IV). We suggest, for each of them, a revision strategy directed toward a "conservative revision procedure" using conservative or primary component. Out of our 21 cases, none underwent further revision due to mechanical failure (follow-up ranging from 6 to 152 months, mean 54 months). We had two cases of re-operation: one for early septic loosening and one for prosthetic modular neck fracture. CONCLUSIONS: If literature offers well-established guidelines to femoral revision of conventional stems, there is, on the other hand, a lack of data about revision strategies in presence of failed conservative implants. Although the mean follow-up of our procedures is still too short (4.5 years) to give final conclusions, we would leave a message: a conservative hip arthroplasty is not a "one time" opportunity for young and active people. A "conservative revision" is a valid option for at least a part of them, when an early failure of primary procedure occurred.

A new classification for proximal femur bone defects in conservative hip arthroplasty revisions.

INTRODUCTION: In the last three decades, total hip replacement in young patient became a habitual procedure. Principles of bone preservation are pushing many surgeons to implant conservative femoral components in patient younger than 65 years. Despite an overall good survivorship and clinical outcomes of conservative implants, failed cases are reported and the need to revise a conservative femoral component became an occasional procedure (with high prevalence of failed resurfacing implants). METHODS: During conservative femoral component revisions, we analyzed proximal bone stock preservation, considering the type of original component removed, etiology of failure, timing of revision, and femoral explantation technique. RESULTS: We identified four patterns of proximal femoral changes (types I-IV). We suggest, for each of them, a revision strategy directed toward a "conservative revision procedure" using conservative or primary component. Out of our 21 cases, none underwent further revision due to mechanical failure (follow-up ranging from 6 to 152 months, mean 54 months). We had two case of re-operation: one for early septic loosening and one for prosthetic modular neck fracture. CONCLUSIONS: If literature offers well-established guidelines to femoral revision of conventional stems, there is, on the other hand, a lack of data about revision strategies in presence of failed conservative implants. Although the mean follow-up of our procedures is still too short (4.5 years) to give final conclusions, we would leave a message: a conservative hip arthroplasty is not a "one-time" opportunity for young and active people. A "conservative revision" is a valid option for at least a part of them, when an early failure of primary procedure occurred.

Humeral head inferior subluxation in proximal humerus fractures.

PURPOSE: The objectives of this study are to propose a reliable radiologic method for detecting static inferior subluxation of humeral head, to calculate the relative intra- and inter-observer reliability, and to evaluate its presence pre- and post-surgery. METHODS: This is a retrospective observational study of patients surgically treated for a fracture of the proximal humerus. Fractures were classified using Codman-Lego criteria (radiographic, CT images), osteoporosis was assessed. To identify inferior subluxation, an original method is proposed. This measurement was done pre-operatively, at three and 12 month post-operatively. Clinical evaluation was recorded at final follow-up using Constant Score. RESULTS: One hundred fifty fractures surgically treated were studied. Intra- and inter-observer reliabilities were excellent and high, respectively. In pre-operative x-rays, a significant inferior subluxation was noted in 17/150 cases (11.3%), with significant correlation with fracture pattern (p=0.045), female sex (p=0.038), age older than 70 (p=0.003), obesity (BMI>30, p=0.03), and local osteoporosis (p=0.002). At three month of follow-up, 22 cases (14.6%) had inferior subluxation, with significant correlation with female sex (p=0.04), age older than 70 (p=0.002), obesity (p=0.02), pin or screw articular surface perforation (p<0.001). At 12 month of follow-up, seven cases showed persistent inferior subluxation, with significant correlation with age older than 70 (p=0.032), obesity (p=0.041), screw joint perforation and lower Constant Score (p<0.001). DISCUSSION: Inferior subluxation was mostly found in osteoporotic fractures of the elderly, obese, and of female sex both pre- and post-operatively. The intra- and inter-observer reliabilities of proposed radiographic measurement were high and excellent, respectively. CONCLUSIONS: In the early postoperative months, we found a high correlation between inferior subluxation and articular surface perforation; when persisting at later follow-ups, we might speculate that it could represent an early phase of avascular necrosis of the humeral head. LEVEL OF EVIDENCE: Level III, observational study.

Total hip arthroplasty instability in Italy.

Hip dislocation is a major and common complication of total hip arthroplasty (THA), which appears with an incidence between 0.3% and 10% in primary total hip arthroplasties and up to 28% in revision THA. The hip dislocations can be classified into three groups: early, intermediate and late. Approximately two-thirds of cases can be treated successfully with a non-operative approach. The rest require further surgical intervention. The prerequisite to developing an appropriate treatment strategy is a thorough evaluation to identify the causes of the dislocation. In addition, many factors that contribute to THA dislocation are related to the surgical technique, mainly including component orientation, femoral head diameter, restoration of femoral offset and leg length, cam impingement and condition of the soft tissues. The diagnosis of a dislocated hip is relatively easy because the clinical situation is very typical. Having identified a dislocated hip, the first step is to perform a closed reduction of the implant. After reduction you must perform a computed tomography scan to evaluate the surgical options for treatment of recurrent dislocation that include: revision arthroplasty, modular components exchange, dual-mobility cups, large femoral heads, constrained cups, elimination of impingement and soft tissue procedures. The objective is to avoid further dislocation, a devastating event which is increasing the number of operations on the hip. To obtain this goal is useful to follow an algorithm of treatment, but the best treatment remains prevention.

Minimally invasive plate osteosynthesis in proximal humeral fractures: one-year results of a prospective multicenter study.

PURPOSE: The aim of this multicentric study was to evaluate results of minimally invasive plate osteosynthesis (MIPO) for proximal humeral fractures in terms of postoperative shoulder function, radiological outcome and number of complications. METHODS: A consecutive series of 76 patients with proximal humeral fractures were treated with locking plate using a minimally invasive antero-lateral approach in two orthopaedic departments. Functional results with Constant score and radiographic evaluation were available for 74 patients at one-year follow up. RESULTS: The patients achieved a mean Constant score of 71 (range 28-100). Each functional result was evaluated also for both centres without significant differences. Significant statistical differences were only found for younger patients with better results (p < 0.05). Twenty patients (27%) developed complications. Subacromial impingement occurred in 16.2% of cases for varus malreduction (6.7%) and for too proximal plate positioning (9.5%). Primary screws perforation (2.7%), secondary perforation due to cut-out (1.4%), avascular necrosis (AVN) of humeral head (1.4%), partial resorption of greater tuberosity (2.7%), secondary dislocation of the greater tuberosity (2.7%) and stiffness (2.7%) were the other complications observed. CONCLUSIONS: The MIPO technique for proximal humeral fractures was safe and reproducible for most common patterns of fracture. Major complication rate was apparently low due to a soft tissue sparing, deltoid muscle and circumflex vessels, with easy access of the bar area to correct positioning of the plate.

Bone loss management in total knee revision surgery.

PURPOSE: Bone stock reconstruction in TKR surgery is one of the biggest challenges for the surgeon. According to some, authors causes of bone stock loosening are multiple, including stress shielding, osteolysis from wear, septic or aseptic loosening, and bone loss caused by a poorly balanced implant. Moreover, bone loss may be iatrogenic at the time of implant removal, indicating that bone preservation during implant removal is critical. METHODS: Defect localization and extension affect the surgeon's decisions about the choice of the surgical technique and the type of plant to be taken. Today there are several options available for bone deficiency treatment. The treatment choice is undoubtedly linked to the cause of revision, experience and personal philosophy, but it is necessary to consider also the patient's age, expectations of life, functional requirements and bone quality. Many authors prefer bone stock reconstruction techniques in patients with high bone quality and a better quality of life with more prospects. In patients with lower lease on life and lower bone quality the best bone replacement techniques are of modular systems, wedges, and augments. In cases with septic bone loss, more or less extended, different authors recommend reducing bone grafts in favor of modular prostheses to reduce the risk of graft contamination. RESULTS: All of these techniques have been shown to be durable in midterm outcomes, but concerns exist for a number of reasons, including disease transmission, resorption, fracture, immune reaction to allograft, the cost of custom prostheses, the inability to modify the construct intraoperatively and the overall technical challenge of applying these techniques. CONCLUSIONS: The choice between different surgical options depends on bone defect dimension and characteristics but are also patient-related. Reestablishment of well-aligned and stable implants is necessary for successful reconstruction, but this can't be accomplished without a sufficient restoration of an eventual bone loss.

Results of hip resurfacing.

BACKGROUND: The renewed popularity of resurfacing hip arthroplasty in the last 10 years has generated a remarkable quantity of scientific contributions based on mid- and short-term follow-up. More than one paper has reported a consistent early revision rate as a consequence of biological or biomechanical failure. Two major complications are commonly described with resurfacing implants: avascular necrosis and femoral-neck fracture. A close relationship between these two events has been suggested, but not firmly demonstrated, whereas cementing technique seems to be better understood as potential cause of failure. METHODS: We performed an in vitro study in which four different resurfacing implants were evaluated with a simulated femoral head, two types of cement, (low and high viscosity) and two cementing techniques: direct (cement apposition directly on the femoral head) and indirect (cement poured into the femoral component). RESULTS: High-viscosity cement showed homogeneous distribution over the entire femoral head. Low-viscosity cement showed a massive polar concentration with insufficient, if not absent, distribution in the equatorial zone. CONCLUSION: Polar cement concentration could be a risk factor for early implant failure due to two effects on the femoral head: biological (excessive local exothermic reaction could cause osteocyte necrosis) and biomechanical (which could lead to uneven load distribution on the femoral head).

Patterns of cement distribution in total hip resurfacing arthroplasty.

In this in vitro study, 4 different resurfacing implants have been evaluated with a simulated femoral head: 2 types of cement have been used (low and high viscosity) and 2 different cementing techniques have been performed: direct (cement apposition directly on the femoral head) and indirect (cement poured into the femoral component). High-viscosity cement shows a homogeneous distribution all over the femoral head. Low-viscosity cement shows a massive polar concentration with insufficient if not absent distribution in the equatorial zone. Polar cement concentration could be held as a risk factor for early implant failure. It could have 2 effects on femoral head: biologic (excessive local exothermic reaction could cause necrosis of the osteocytes) and biomechanical (it could lead to uneven load distribution on the femoral head).

Radiographic patterns of osteoporotic proximal humerus fractures.

OBJECTIVE: The objectives of the study were: a) to identify osteoporotic proximal humerus fractures in a large consecutive series of patients; b) to identify radiographic fracture patterns among osteoporotic and non-osteoporotic proximal humerus fractures; and c) to calculate intra- and inter-observer reliability of assessment of osteoporosis and of radiographic fracture patterns. METHODS: This was a prospective observational study of patients admitted to the emergency department affected by a proximal humerus fracture between June 2014 and June 2016. Three researchers evaluated demographic data and comorbidities, x-rays and CT-scans. A new evaluation method for assessment of osteoporosis was proposed; 7 radiographic fracture patterns were studied. Reliabilities between intra- and inter-tester evaluations, and correlations between the presence of osteoporosis and the 7 radiologic fracture patterns were calculated. RESULTS: Two hundred twenty-five patients with a humeral fracture were recruited. Their mean (26-95, 32) age was 58. Of those, 163 (72.4%) were identified as osteoporotic. Among the three raters, the intra- and inter-observer agreement using the proposed methods were high or excellent. Significant correlations with diagnosis of osteoporosis were found with Codman-Lego type 12(p = 0.041), metaphyseal comminution(p < 0.001), impaction of fragments(p = 0.023), comminution of tuberosities(p = 0.037), inferior subluxation(p = 0.029). Intra- and inter-tester reliability of evaluation of these osteoporotic fracture patterns were high. CONCLUSIONS: Osteoporosis of the proximal humerus was identified in 72% of patients during a two year period; most of these patients were elderly females sustaining low energy trauma. These fractures showed to have specific radiographic patterns, as comminution of metaphysis and tuberosities, impaction of fragments, and inferior subluxation of the humeral head. These patterns can be assessed with the simple observation of a 2-plan view of a radiograph, without the use of specific software.

Current concepts, classification, and results in short stem hip arthroplasty.

Various short hip stems have been introduced with differing implant concepts of femoral fixation and implant length. There is a lack of proper classification for short hip stems, with a clear and accepted definition for implant length and extent of bone preservation in the metaphyseal and diaphyseal femur. This study analyzed the length of short hip stems. Stems were divided into collum, partial collum, and trochanter-sparing implants. An additional category was added, trochanter harming, which was defined as interruption of the circumferential integrity of the femoral neck. For all of the femoral components described, the designs were compared, excluding stems with insufficient clinical data. The 15 finally selected stems were classified as collum (1 stem), partial collum (7 stems), trochanter sparing (4 stems), and trochanter harming (3 stems). Mid-term results (>5 years of follow-up) were available for only 3 designs in the partial collum group. Taking into account the results of short-term studies (<5 years of follow-up), the femoral revision rate per 100 observed component years was <1 for most total hip arthroplasties. However, the studies varied greatly regarding level of significance, and short hip stems without published results are available commercially. Short hip stems cannot be circumscribed by a simple length limit. For some designs, clinical data collected from large patient cohorts showed a survivorship comparable to traditional stems. In cases that must be revised, this often can be performed with a conventional primary stem, fulfilling the promise to preserve bone for potential future revisions in younger patients.