Long-stemmed Implants Research Articles

Comparison of Short Uncemented Metaphyseal Stem and Long-Stem Reverse Shoulder Arthroplasty in Proximal Humerus Fractures: Preliminary Study at 2-Year Follow-Up.

Introduction: In the last few years, short metaphyseal-socket prosthetic humeral stems have been introduced for reverse shoulder arthroplasty (RSA). A short stem may have advantages in humeral force distribution, reducing shear stress and preserving bone stock, keeping in mind the need for possible future revision surgery. The main objective of our study was to validate the use of a short stem prosthesis in the surgical treatment of humeral fractures by comparing clinical and radiological outcomes of our studied implant with those obtained with the use of traditional long-stem implants. Methods: In this multicentric, controlled prospective study, 125 patients with proximal three- or four-fragment humerus fractures were selected and treated with RSA. A short stem was used in group A (n = 53, mean age: 75.6 ± 5.6 years old), and a long stem was used in group B (n = 72, mean age: 71.76 ± 3). Active range of motion (ROM), Constant score (CS), Quick DASH, American Shoulder and Elbow Surgeons Shoulder (ASES) score, and Visual Analog Scale (VAS) scores were collected and analyzed at 2 years mean follow-up, as well as humeral and glenoid bone resorption (sum Inoue scores and Sirveaux scores were used). Results: No statistically significant differences were observed between group A and B in ROM, Constant score (51.69 ± 15.8 vs. 53.46 ± 15.96, p > 0.05), Quick DASH (31.5 ± 21.81 vs. 28.79 ± 13.72, p = 0.85), ASES (82.53 ± 17.79 vs. 84.34 ± 15.24, p = 0.57), or the VAS (0.53 ± 1 vs. 0.56 ± 1.07, p = 0.14) at the final follow-up. No statistically significant differences were found in the radiographic parameters between the two groups. No statistically significant differences were found for the average degree of humeral and glenoid bone resorption either. Conclusions: The use of a short metaphyseal-socket stem can be considered a safe, effective, and feasible option in reverse shoulder arthroplasty for treating proximal humerus fractures. Our results are encouraging, with no statistically significant differences identified between the proposed treatment and traditional long stems.

Survival Rates and Patient-Reported Outcomes Support the Use of Custom Cement-Over Megaprosthesis (CCOM) in Complex Revision Lower Limb Arthroplasty

BackgroundPatients presenting with periprosthetic osteolysis or fracture between ipsilateral hip and knee arthroplasties are challenging to treat successfully. Long-stem implants, osteopenic bones, and patient comorbidities all represent considerable surgical challenges. Poor results of fracture fixation in this group, coupled with the desire to retain well-performing implants and minimize soft-tissue trauma led to the developmentof the custom cement-over megaprostheses (CCOM). The aims of the study were to evaluate implant survivals, complications, and patient outcomes in those undergoing CCOM within our institution. MethodsA retrospective analysis of patients undergoing CCOM between 2002 and 2022 was performed. We studied 34 cases, 33 patients, one patient underwent staged bilateral surgery with 26 women and 8 men. Indications: trauma (16), failure of implants /aseptic loosening (9), or joint pathology. The mean Charlson comorbidity index was 3.5 (range, 0 to 8). All patients were followed up (mean 75 months [range, 9 to 170]) at 6 weeks, 6 months, 1 year, and annually thereafter. The VAS, EuroQol-5D-3L and MSTS scores were collected at 1 year. ResultsImplant survival defined by the primary outcome (all-cause revision of the implant at any time point) at 12 months of 97% (32 of 33). In surviving patients, implant survival was 90% (18 of 20) and all 7 survived at 5 and 10 years, respectively. Implant survival including those in the primary outcome group and those free of infection at 12 months was 84.8% (28 of 33) and in surviving patients, implant survival was 70% (14 of 20) and 7 out of 7 at 5 and 10 years, respectively. ConclusionsThe CCOM technique demonstrates good implant survivorships and satisfactory patient-reported outcomes in complex, often frail patients who have compromised bone stock. This series confirms the technique as an established alternative to total femoral replacement in these cases.

The effect of shoulder prosthesis stem length on failure due to torsional loading. A biomechanical study in composite humeri

Shoulder arthroplasty is becoming increasingly common. With evolving implant designs, multiple humeral stem options exist for the surgeon to choose from. New stemless and short-stem systems are modular, remove less native bone stock, and better adapt to patient anatomy. It has been suggested that shorter stem implants may be protective against periprosthetic fracture; however, this has not been mechanistically evaluated. Therefore, this study aimed to biomechanically test synthetic humeri with long-stem, short-stem, and stemless arthroplasty components in a torsional manner to evaluate their response to loading and characterize failure. Twenty-four synthetic humeri were implanted with long stem, short stem, or stemless uncemented prosthesis, 8 in each group. Humeri were mounted in a custom testing jig with a morse taper interfacing with a mechanical testing system. After a 20N axial force, specimens were torsionally loaded to failure at 15 degrees/sec, with 50 Hz collection. Torque vs. rotation curves were generated for each specimen, and stiffness, yield, ultimate strength, and failure load were measured. ANOVA and post hoc pairwise comparisons were used to assess effect of stem type on mechanical test variable. The association of the stem type with fracture type was analyzed by a Fisher's Exact test. Statistical significance was set at P<.05. During torsional loading, long-stem implants were significantly stiffer than short or stemless implants. The angle of implant yielding was similar across stem designs; however, stemless implants had a lower yield torque. This correlated with a decreased yield energy in stemless compared to short stems as well. Maximum torque and failure torque was also significantly higher in short-stem and long-stem implants compared to stemless. Periprosthetic fractures in shoulder arthroplasty are a concern in low-energy trauma, and stem design likely plays a significant role in early implant-bone failure. Our results suggest stemless implants under torsional load fail at lower stress and are less stiff than stemmed implants. The failure mechanism of stemless implants through metaphyseal cancellous bone emphasizes the effect bone quality has on implant fixation. There is likely a balance of torsional stability to survive physiologic loads while minimizing diaphyseal stress and risk of diaphyseal periprosthetic fracture. This combined with revision and fixation options represent decisions the surgeon is faced with when performing shoulder arthroplasty.

Shaft Fractures in Patients Requiring Primary or Revision Total Knee Arthroplasty Can Be Successfully Treated with Long-Stemmed Implants without Additional Fixation.

The aim of this study was to evaluate the bone union, complication rate, clinical and functional outcomes of long-stemmed total knee arthroplasty (TKA) in patients with periprosthetic femoral or tibial shaft fractures and in patients with femoral or tibial shaft fractures with coexisting advanced knee osteoarthritis (OA). This retrospective study comprised 25 patients who underwent surgery due to tibial or femoral shaft fractures: (1) with coexisting severe knee OA or (2) with a periprosthetic fracture requiring implant exchange. In all cases, fracture stabilization was performed intramedullary with the use of long-stemmed implants without the use of additional fixation material (plates, screws, or cerclage). Bone union was achieved in 22/25 patients (88%). One patient required revision with additional plate stabilization due to non-union, and asymptomatic partial bone union was observed in two cases. The group with periprosthetic fractures demonstrated good clinical (mean 73.1 ± 13.3) and moderate functional (mean 59.2 ± 18.8) outcomes in the Knee Society Scoring system (KSS). In the group with shaft fracture and coexisting OA significantly higher clinical (excellent results, mean 84.1 ± 11; p = 0.03) and functional (good results, mean 76.2 ± 20.6; p = 0.04) results were noted. There were no statistically significant differences in terms of range of motion (ROM) or complication rate between these two groups. One-stage TKA with a long-stemmed implant without the use of additional fixation material is an effective method for the treatment of femoral or tibial shaft fractures in patients who require joint replacement. Despite being technically demanding, the approach yields bone union and moderate to excellent clinical and functional outcomes with a relatively low complication rate.

Optimum stem length for mitigation of periprosthetic fracture risk following primary total knee arthroplasty: a finite element study

PurposeDue to age-related changes to the material properties and thinning of the cortical bone structure, older patients with osteoporosis may be at greater risk of femoral fracture following total knee arthroplasty. This study investigates whether there is a potential role for stemmed prostheses in such scenarios to help mitigate peri-implant fracture risk, and if so what should the optimum stem length be to balance surgical bone loss with reduced fracture risk.MethodsFinite element models of the distal femur implanted with four different implant types: a posterior stabilising implant, a total stabilising implant with short stem (12 mm × 50 mm), a TS implant with medium stem (12 mm × 75 mm), and a TS implant with long stem (12 mm × 100 mm), were developed and analysed in this study. Osteoporotic properties were applied to the implanted femurs and the periprosthetic stresses and strains of each were recorded.ResultsAll stem lengths examined were found to lead to a reduction in periprosthetic stress in comparison with a primary stemless implant, with short-, medium-, and long-stemmed implants leading to an 11, 26, and 29% reduction in stress, respectively.ConclusionThe results of this study show that periprosthetic stress and therefore fracture risk in old osteoporotic patients may be reduced through the use of stemmed femoral components. Of the three stems investigated, a medium-length stem is found to represent the best balance between bone preservation at the time of surgery and reduction in periprosthetic stress following implantation.

Salvage procedures and implant selection for periprosthetic femoral fractures

Periprosthetic femoral fractures with severe bone loss are challenging to treat. There are various treatment options, depending on the severity of the bone loss, age and activity of the patient and experience of the surgeon. This review focuses on the treatment of these Vancouver type B3 fractures with long-stem implants, proximal femoral replacements, allograft-prosthesis composites and cortical strut grafting.

Periprothetische Frakturen nach Knietotalendoprothetik

The increasing implantation rates of knee arthroplasties are associated with a growing prevalence of complications like periprosthetic fractures. Underlying patient, implant and/or operation technique-related risk factors contribute to these fractures which often occur after minor trauma. In the diagnostic process, fracture dislocation, implant stability, and integrity of the extensor mechanism have to be assessed. Valid classification systems are available to guide treatment decisions. Treatment goals are precise reposition, stable fixation, restoration of function, and early mobilization. In the case of an operative revision, the surgeon has to know the implanted device and has to be prepared for extended procedures and revision arthroplasty. Less invasive fixation devices like retrograde nailing or LISS are often sufficient to stabilize femoral supracondylar fractures, while loosening of the implant often requires extended exchange arthroplasty. Tibial fractures are often associated with osteolysis and bone loss which has to be addressed with bone grafts or augmented revision implants. Long-stemmed implants allow bypassing of the reconstructed defect and provide a stable solution for early mobilization. Patella fractures with stable or asymptomatic implants and continuity of the extensor mechanism should be treated conservatively. If reconstruction becomes necessary, results are often associated with significant functional limitations.

Hip arthroplasty for salvage of failed treatment of intertrochanteric hip fractures.

Failed treatment of an intertrochanteric fracture typically leads to profound functional disability and pain. Treatment with repeated attempts to gain union and to preserve the host femoral head usually is preferred for young patients, but salvage treatment with hip arthroplasty may be considered for selected older patients with poor bone quality, bone loss, or articular cartilage damage. The purpose of the present study was to evaluate the results and complications of hip arthroplasty performed as a salvage procedure after the failed treatment of an intertrochanteric hip fracture. Between 1985 and 1997, sixty patients (forty-nine women and eleven men) with a mean age of seventy-eight years were treated at our institution with hip arthroplasty after the failed treatment of an intertrochanteric fracture. Thirty-two patients had a total hip arthroplasty with a cemented cup (twenty-four patients) or an uncemented cup (eight patients), twenty-seven had a bipolar hemiarthroplasty, and one had a unipolar hemiarthroplasty. A calcar-replacement design, extended-neck stem, or long-stem implant was used in fifty-one of the sixty hips. Ten patients died within two years (all with the implant intact), and six were lost to follow-up. The remaining forty-four patients were followed for a mean of five years (range, two to fifteen years). At the time of the last follow-up, thirty-nine patients had no or mild pain and five had moderate or severe pain; in all of these patients, the pain was in the region of the greater trochanter. Forty patients were able to walk, twenty-six with one-arm support or less. Twelve patients had a total of thirteen medical complications postoperatively. A total of five reoperations were performed: two patients had a revision, one had a rewiring procedure because of trochanteric avulsion, one had late removal of trochanteric hardware, and one had débridement of fat necrosis. One patient had two dislocations, both of which were treated with closed reduction. Kaplan-Meier survivorship analysis with revision of the implant for any reason as the end point revealed a survival rate of 100% at seven years and 87.5% (95% confidence interval, 67.3% to 100%) at ten years. Hip arthroplasty is an effective salvage procedure after the failed treatment of an intertrochanteric fracture in an older patient. Most patients have good pain relief and functional improvement. Calcar-replacement and long-stem implants often are required. Despite the operative challenges, surprisingly few serious orthopaedic complications were associated with this procedure in the present study.

Femoral revision: Distal fixation with fluted, tapered grit-blasted stems

Fluted, tapered grit-blasted titanium stems for revision total hip arthroplasty have been used extensively in Europe and have been reported to provide mostly favorable results. These stems are tapered to gain axial stability and fluted to gain rotational stability in the femoral diaphysis. Grit-blasted titanium provides a surface for bone ongrowth. Such implants can solve certain problems not addressed easily by other standard revision techniques. The clinical durability of modular implants, introduced to make these implants more user-friendly and more versatile, remains to be proved. These implants require special techniques for implantation, particularly when long-stemmed implants are used. Copyright 2002, Elsevier Science (USA). All rights reserved.

The use of the cystoscope in revision hip arthroplasty

Good distal visualization is an important factor to the success of any revision operation, particularly in the presence of infection, osteolytic defects, and long-stemmed implants. There are 2 main problems: i) the need for a powerful light source that does not itself impair the view and ii) actual vision while operating down the canal. In the past, surgeons tried headlights, hand-held microlights, and windowing the distal femur in an effort to improve the view. None of these techniques solved the problem.

Periprosthetic Fractures of the Humerus

Periprosthetic fractures of the humerus complicate 2-4% of total shoulder arthroplasties. Intraoperative fractures are more common than those that occur after surgery and are usually the result of faulty surgical technique. Patients with osteoporosis are at increased risk for periprosthetic fracture of the humerus, and these injuries are most common in patients with rheumatoid arthritis. Common mechanisms of intraoperative fracture include excessive external rotation forces because of poor operative exposure, improper starting hole location, and too forceful impaction. Intraoperative fractures should be stabilized with cerclage wires, and long-stem implants should be used if the fracture involves the shaft of the humerus. Postoperative fractures frequently compromise the functional abilities of the patient; operative treatment seems to give the best results. Treatment is based on a classification of the fracture, accounting for the location of the fracture and whether the prosthesis is stable or loose. Postoperative fractures of the distal humerus that are extra-articular may be safely treated nonoperatively.

The use of bulk allografts in revision knee arthroplasty

During the revision of a failed total knee implant, when large osseous defects are encountered, the surgeon has the following three options for managing severe bone loss: revision with a custom implant, revision with a rotating-hinge component, or reconstruction with an allograft and a long-stemmed revision component. An allograft reconstruction replaces the damaged bone, albeit with dead bone; whereas the other two options require additional bone to be removed. By using a bone defect classification system preoperatively, the surgeon estimates the extent of bone damage and orders the proper revision system and allograft material. A durable revision arthroplasty is achieved by using long-stemmed implants that provide axial stability, cementless stems that permit compressive loads, and step cuts that achieve rotational stability.

Bone remodelling after total hip arthroplasty

Bone remodelling of the proximal femur following total hip arthroplasty (THA) is related to stress deviation with respect to physiological condition. The clinical relevance of this process is much debated with respect to its role in THA failure. In the present study a group of 475 An.C.A. anatomic cementless stems implanted in our institution were assumed as clinical reference. Of them, 294 had a short stem and 181 had a long stem. Stress shielding was X-ray evaluated in each patient. The survivorship analysis of this study group (negative events = stress shielding) showed significantly (p<0.05) lower survival rates at 25 months follow-up for patients with long-stem implants. A 3-D FEM model of the proximal femur was used to analyse the load transfer mechanism for the two types of stems in fully or proximally only bonding conditions. Little difference was predicted in the proximal stress magnitudes for the different stem lengths. On the contrary, stem-bone bonding leads to a notable increase in the stress shielding.