The cemented humerus and non-cemented glenoid: The optimal hybrid solution for total shoulder arthroplasty

Hybrid fixation of total joint arthroplasty has been recognized as an accepted form of surgical approach in multiple joints. Principles of implant fixation should focus on durability and on providing secure long-term function. To date, there is no conclusive evidence that pressed-fit humeral stem fixation has an advantage over well-secured cemented humeral fixation. Although revision may require cement removal, a well-fixed bone—ingrowth implant may require slatting and osteotomy of the humerus. On the contrary, need for revision in arthroplasty due to inadequate implant fixation has almost universally revolved around the failure of cement fixation and loosening of the glenoid component. A case will be made based on 30 years of experience of a surgeon performing total shoulder arthroplasty using secure modern cement-fixation techniques of humeral components. More recently, over the past 10 years an extremely high rate of durable secure glenoid implant fixation has been achieved using press-fit tantalum porous anchorage of polyethylene glenoid components. This has resulted in no cases of loosening of glenoid fixation and only one case of glenoid component fracture with greater than 95% survivorship over a 10-year period. A combination of well-cemented humeral stem and trabecular metal anchorage of the glenoid has provided durable and long-lasting function in primary total shoulder arthroplasty.     

Periprosthetic fractures in total shoulder replacement

Periprosthetic fracture is an uncommon complication of shoulder arthroplasty. Over an 18-year period, we identified 38 fractures occurring either during or subsequent to a shoulder arthroplasty. Among intraoperative fractures, the humeral shaft was involved in nine cases, the greater tuberosity in five, the proximal humeral metaphysis in two, the glenoid in four, and the coracoid process in two. Postoperative fractures involved the humeral shaft in 15 cases and the coracoid process in one. Thirty-three fractures occurred in women compared with five in men. Rheumatoid arthritis was the most common diagnosis. Our results suggest that intraoperative shaft fractures occurring at or below the stem tip can be successfully managed by using a long stem implant to bypass the fracture. Supplementary cerclage wires or cables are added if additional stabilization is needed. Eleven of the 15 postoperative shaft fractures were initially treated with a cast or brace. Nonoperative treatment led to union in 6 of the 11 (54.5%), but failed in 5. We recommend a trial of closed treatment if a satisfactory reduction can be obtained and maintained. If acceptable alignment cannot be achieved, or if delayed or nonunion develops, recommended surgical options include internal fixation with a plate if the prosthesis is well fixed, or revision with a long-stem prosthesis. Three of the four intraoperative glenoid fractures precluded glenoid resurfacing. Except for a nonunion in one case, greater tuberosity fractures did not impact the ultimate clinical outcome. Coracoid process fractures were also not clinically significant.     

A review of humeral stem removal during revision shoulder arthroplasty

Despite the overwhelming clinical success of shoulder arthroplasty, several situations may arise that necessitate revision arthroplasty. This often requires removal of the humeral component. Extraction of a humeral prosthesis is a technically demanding procedure, which requires an understanding of the indications for humeral component explantation, careful preoperative planning, knowledge of the humeral component to be removed, a grasp of several different methods of stem removal, and the tools required. Cement extraction often poses substantial technical challenges and requires further specialized instruments. Surgeons should be prepared to manage specific complications that may arise such as canal perforation and humerus fracture.     

Comminuted periprosthetic humeral fracture after reverse shoulder prosthesis

Periprosthetic fractures represent a severe complication after joint replacement. A case of comminuted displaced humeral fracture around the stem of a SMR reverse shoulder prosthesis is reported. The patient was a 81-year-old lady who had had a total shoulder replacement 28 months previously. The surgical solution consisted of a partial revision of the modular implant with conservation not only of the glenoid component but also of the prosthetic humeral body, which was well fixed in the humeral metaphysis. The humeral stem was removed and a long uncemented revision stem was implanted providing fracture stabilisation and allowing early mobilisation.     

Comminuted periprosthetic humeral fracture after reverse shoulder prosthesis

Periprosthetic fractures represent a severe complication after joint replacement. A case of comminuted displaced humeral fracture around the stem of a SMR reverse shoulder prosthesis is reported. The patient was a 81-year-old lady who had had a total shoulder replacement 28 months previously. The surgical solution consisted of a partial revision of the modular implant with conservation not only of the glenoid component but also of the prosthetic humeral body, which was well fixed in the humeral metaphysis. The humeral stem was removed and a long uncemented revision stem was implanted providing fracture stabilisation and allowing early mobilisation.     

Treatment of periprosthetic humerus fractures associated with shoulder arthroplasty

The incidence of periprosthetic humerus fracture associated with shoulder arthroplasty is approximately 0.6% to 3%. Fractures of the humerus occur most often intraoperatively and are more common during total shoulder arthroplasty than hemiarthroplasty because of difficulties in gaining access to the glenoid. Osteopenia, advanced age, female sex, and rheumatoid arthritis are medical comorbid factors that may contribute to humerus fractures and associated delayed healing and poorer function. When the humeral prosthetic component is loose or the fracture line overlaps the majority of the length of the prosthesis, revision with a long-stem implant should be considered. When the fracture overlaps the tip of the prosthesis and extends distally, open reduction and internal fixation is recommended. When the fracture is completely distal to the prosthesis and satisfactory alignment at the fracture site can be maintained with a fracture brace, then a trial of nonsurgical treatment is recommended. The primary goals of treatment are fracture union and pain relief. Loss of glenohumeral motion has limited the successful treatment of this challenging problem.     

Fracture of an Exeter 'cement in cement' revision stem: a case report

The 'cement in cement' technique for revision hip arthroplasty has become popular in recent years, particularly in relation to polished taper stems. Since 2006 a short Exeter stem with 44 mm offset has been available specifically for this purpose. We report a fracture of such a stem in the absence of trauma 5 years after the revision procedure. The patient had a BMI of 27.8 and the proximal cement mantle gave good support to the stem. The fracture initiated and propagated from the introducer hole on the shoulder of the prosthesis. Macroscopically there was no defect in this area. This may be an unusual case of fatigue failure.     

Constrained arthroplasty: its use and misuse

Constrained arthroplasty is occasionally needed to salvage a destroyed glenohumeral joint when the rotator cuff is nonfunctioning and when an unconstrained prosthesis will not suffice. There is a high failure rate because of the severe forces between such a device and the contiguous bone. Accordingly, it is essential to know the limitations of constrained arthroplasty and when it should be avoided. For example, when the bone of the glenoid vault is highly demineralized or deficient or if there is a history of seizure disorder or alcoholism, use of such a device is contraindicated. Postoperatively, excessive force and extremes of motion should also be avoided during the rehabilitation program to avoid bone fracture or dislocation of the prosthesis. Various complications have been observed with constrained arthroplasty, including dislocation, bone fracture, pullout of the glenoid, infection, radial nerve injury after extrusion of bone cement through the humeral cortex when the cement has been pressurized, and screw breakage in a relative small number of cases after metal fatigue and loosening of the glenoid component. When the glenoid component has pulled away from the glenoid vault, it may be necessary to remove this component; the humeral head may be fitted with a bipolar 40- to 44-mm acetabular component, thereby allowing at least preservation, if not the active function of the shoulder contour.     

„Resurfacing“ des Humeruskopfes

Surface replacement arthroplasty of the shoulder offers the ability to restore anatomy and biomechanics of the glenohumeral joint, if sufficient humeral bone stock of at least 60% of the humeral head is preserved and no severe deformity is present. The implantation following the individual anatomy helps to avoid complications such as prosthetic malpositioning and periprosthetic fractures. While the use of a glenoid component is technically demanding, revision to a stem prosthesis is relatively easy because of bone stock preservation.Indications for humeral head resurfacing are osteoarthritis (OA), rheumatoid arthritis (RA), avascular necrosis stages 2-4, and stable forms of cuff tear arthropathy (CTA). Published results for OA and RA are comparable to those obtained with modern modular stem prostheses; the use in CTA appears promising under "limited goals criteria."     

Current status and perspectives of shoulder replacement

Summary Basis of the modern shoulder implants is the Neer II-system, a non constrained total shoulder prosthesis with conforming radii of curvature and improved protection against dislocation. The second generation of shoulder prosthesis is based on the geometric shaft design of the Neer II prosthesis and offers not only a variety of modular head- and shaft-sizes but also through different radii a physiologic rotation-translation-mechanism. The third generation of humeral head prosthesis carries the concept of an anatomic reconstruction one step further and enables the surgeon to adjust the inclination and the eccentric offset of the humeral head to restore the centre of rotation. The latest development in shoulder arthroplasty are humeral head prosthesis with a fully variable 3-dimensional modularity to independently adjust the prosthestic head position regardless of the individual shaft geometry. This achieves a 3-dimensional adaptability of the prosthetic head about the stem axis in the coronary and in the sagittal plane. Besides of the humeral shaft prosthesis an alternative concept of shoulder joint replacement is established – the replacement of the humeral head articular surface. A hemispheric surface prosthesis – cup arthroplasty – is cemented onto the residual humeral head, which eliminates the obligatory humeral head resection and the reaming of the medullary canal. Bipolar shoulder prosthesis are humeral shaft prosthesis with a bi-rotational head system. Their indication is limited to pre-existing lesions of the rotator cuff and/or the glenoid surface. The inverse total shoulder prosthesis reverses the articular surface morphology of the humeral head and the glenoid. The hemispheric glenoid component serves as the centre of rotation for the concave epiphyseal proximal humerus component. This implant is especially used in cases of massive rotator cuff deficiences. The role of shoulder prosthesis in treating acute humeral head fractures needs special consideration. A fracture prosthesis has to restore the exact length of the humerus, the centre of rotation, and the anatomical retroversion. Positioning of the tubercula and their adequate osteosynthesis is most critical and fundamental to ensure a correct healing process. A failed consolidation of the tubercula does not lead to a satisfying result. The shoulder joint replacement can be sufficiently fixated in cemented, cementless or hybrid techniques. Today several component design variations of cemented glenoid implants exist. Their main distinction is the fixation system which can be divided into two main groups – the keel – and the peg-shaped glenoid components. The peg-shaped anchorage system shall guarantee a greater stability against shear-forces. Cementless glenoid components consist of a polyethylen inlay and a surface treated metal-back with an integrated fixation system. These fixation systems are object of intensive biomechanical research and range from conventional screw fixation to specialised cone systems and self-cutting cage-screw-systems. The critical area of cementless glenoid components is the transition zone of the PE-inlay and the metal-back because of high force development. The question of implanting a hemi- or total shoulder prosthesis is answered by the morphologic changes of the glenoid articular surface, which includes the size of the subchondral defect and the underlying etiology of the shoulder joint disease, and the age of the patient. Preoperative planning must consist of an adequate radiologic work-up – X-ray, CT or MRI – to accurately assess the glenoid morphology. G. Walch categorised the different glenoid lesions and developed a very important classification of possible glenoid deformations. To compare and evaluate the operative results one must consider the different shoulder prosthesis and the discrepancies between a hemi- and a total shoulder prosthetic replacement. Looking at the loosening and survival rate of the implant the results are related to the type of prosthesis and the preoperative diagnosis. The Neer total shoulder prosthesis has a 15 year survival rate of 87 %, compared to 74 % of the hemi-prosthesis. The objective for the future has to be to further advance the development of prosthetic components, especially for primary joint replacement in acute humeral head fractures. Another point of interest is how to reduce the still existing high loosening rates of the glenoid components. A fairly new research-field is the computer-assisted surgery, e. g. navigation systems and robotics. The computer-assisted navigation could be of great advantage to accurately find the individual resection plane (inclination and restroversion) of the humeral head. The use of a surgery-robot could be very helpful to reproducibly achieve the desired conformity of the articular surface when preparing the glenoid.      

Current status and perspectives of shoulder replacement

Basis of the modern shoulder implants is the Neer II-system, a non constrained total shoulder prosthesis with conforming radii of curvature and improved protection against dislocation. The second generation of shoulder prosthesis is based on the geometric shaft design of the Neer II prosthesis and offers not only a variety of modular head- and shaft-sizes but also through different radii a physiologic rotation-translation-mechanism. The third generation of humeral head prosthesis carries the concept of an anatomic reconstruction one step further and enables the surgeon to adjust the inclination and the eccentric offset of the humeral head to restore the centre of rotation. The latest development in shoulder arthroplasty are humeral head prosthesis with a fully variable 3-dimensional modularity to independently adjust the prosthestic head position regardless of the individual shaft geometry. This achieves a 3-dimensional adaptability of the prosthetic head about the stem axis in the coronary and in the sagittal plane. Besides of the humeral shaft prosthesis an alternative concept of shoulder joint replacement is established – the replacement of the humeral head articular surface. A hemispheric surface prosthesis – cup arthroplasty – is cemented onto the residual humeral head, which eliminates the obligatory humeral head resection and the reaming of the medullary canal. Bipolar shoulder prosthesis are humeral shaft prosthesis with a bi-rotational head system. Their indication is limited to pre-existing lesions of the rotator cuff and/or the glenoid surface. The inverse total shoulder prosthesis reverses the articular surface morphology of the humeral head and the glenoid. The hemispheric glenoid component serves as the centre of rotation for the concave epiphyseal proximal humerus component. This implant is especially used in cases of massive rotator cuff deficiences. The role of shoulder prosthesis in treating acute humeral head fractures needs special consideration. A fracture prosthesis has to restore the exact length of the humerus, the centre of rotation, and the anatomical retroversion. Positioning of the tubercula and their adequate osteosynthesis is most critical and fundamental to ensure a correct healing process. A failed consolidation of the tubercula does not lead to a satisfying result. The shoulder joint replacement can be sufficiently fixated in cemented, cementless or hybrid techniques. Today several component design variations of cemented glenoid implants exist. Their main distinction is the fixation system which can be divided into two main groups – the keel – and the peg-shaped glenoid components. The peg-shaped anchorage system shall guarantee a greater stability against shear-forces. Cementless glenoid components consist of a polyethylen inlay and a surface treated metal-back with an integrated fixation system. These fixation systems are object of intensive biomechanical research and range from conventional screw fixation to specialised cone systems and self-cutting cage-screw-systems. The critical area of cementless glenoid components is the transition zone of the PE-inlay and the metal-back because of high force development. The question of implanting a hemi- or total shoulder prosthesis is answered by the morphologic changes of the glenoid articular surface, which includes the size of the subchondral defect and the underlying etiology of the shoulder joint disease, and the age of the patient. Preoperative planning must consist of an adequate radiologic work-up – X-ray, CT or MRI – to accurately assess the glenoid morphology. G. Walch categorised the different glenoid lesions and developed a very important classification of possible glenoid deformations. To compare and evaluate the operative results one must consider the different shoulder prosthesis and the discrepancies between a hemi- and a total shoulder prosthetic replacement. Looking at the loosening and survival rate of the implant the results are related to the type of prosthesis and the preoperative diagnosis. The Neer total shoulder prosthesis has a 15 year survival rate of 87 %, compared to 74 % of the hemi-prosthesis. The objective for the future has to be to further advance the development of prosthetic components, especially for primary joint replacement in acute humeral head fractures. Another point of interest is how to reduce the still existing high loosening rates of the glenoid components. A fairly new research-field is the computer-assisted surgery, e. g. navigation systems and robotics. The computer-assisted navigation could be of great advantage to accurately find the individual resection plane (inclination and restroversion) of the humeral head. The use of a surgery-robot could be very helpful to reproducibly achieve the desired conformity of the articular surface when preparing the glenoid.     

Chromium, cobalt and titanium metallosis involving a Nottingham shoulder replacement

Metallosis after shoulder replacement has not previously been described in the literature. We report a patient who developed extensive metallosis after implantation of an uncemented Nottingham shoulder replacement. He underwent a revision procedure. Examination of the retrieved prosthesis showed that the titanium porous coating was separating from the humeral stem and becoming embedded in the ultra-high-molecular-weight polyethylene glenoid component, resulting in abrasive wear of the humeral component. There was metallosis despite exchange of the modular humeral head. Both components had to be exchanged to resolve the problem.     

Periprothetische Frakturen bei Schulterendoprothese

Periprosthetic humeral fractures are a rare occurrence, but the incidence will continue to increase in the future because of increasing numbers of shoulder arthroplasty. Intraoperative fractures can be differentiated from postoperative fractures with specific risk factors. Regarding the appropriate treatment there is little evidence in the literature with mostly only small retrospective case series. The key question for therapy is the stability of the stem and the course of the fracture area. According to the Worland classification, A- and C-type fractures with a stable stem can be treated conservatively in most cases, while B?fractures with the fracture around the tip of the prosthesis require operative therapy. With a stable stem, an angular stable osteosynthesis should be performed with long plates; in case of an unstable stem, revision to a long revision stem is preferred. In the future, prospective studies with larger numbers of patient are needed to be able to develop and evaluate a valuable therapy concept for this difficult to treat fracture entity.     

Revision to reverse total shoulder arthroplasty: do short stem and stemless implants reduce the operative burden compared to convertible stems?

BackgroundRevision of prior hemiarthroplasty (HA) or total shoulder arthroplasty (TSA) to reverse shoulder arthroplasty (RSA) is a technically challenging procedure with high complication rates. The purpose of this study was to compare intraoperative complications between convertible humeral stems and nonconvertible humeral stems stratified by stem length for conversion of TSA or HA to RSA.Materials and methodsA multicenter retrospective analysis of patients undergoing revision of a primary TSA or HA to RSA was conducted. Patients were divided into 2 groups based on convertible or nonconvertible humeral stem design from the index surgery. The primary outcome measures were the following intraoperative variables and complications: total operative time, blood loss, intraoperative fracture, overall complication rate, and blood transfusions. Rates were compared between groups and analyzed according to primary stem length for the nonconvertible group.ResultsA total of 279 patients were included in the study, 70 with convertible stems and 209 with nonconvertible stems. About 70% of convertible stems were successfully retained. Operative time was similar between the 2 groups overall. Patients with nonconvertible stems had higher intraoperative blood loss (P = .0001), higher overall complication rate (P = .009), and greater risk of intraoperative fracture (P = .002). Revising stemless and short stems to RSA had significantly reduced operative time compared to standard length stems (97 and 116 minutes vs. 141 minutes, P < .0001 and P = .035, respectively). When revising stemless implants, there was a significantly lower rate of intraoperative fracture (3.6%) compared to short stems (24%, P = .004) and standard stems (23.4%, P = .001). When revising stemless implants to RSA, there was shorter operative time (P= .0001) and similarly low rate of intraoperative fracture (P= .820) compared to convertible stems.ConclusionIn revision of anatomic TSA to RSA, convertible stems lead to lower blood loss and intraoperative fracture rate compared to nonconvertible stems when broadly including all stem types. However, differences appear to be based on stem type. Among nonconvertible stems, revision of short stem and stemless implants are associated with reduced operative time compared to standard length stems. Revision of stemless implants to RSA is associated with the shortest operative time of all implant types as well as a similar rate of intraoperative fracture compared to convertible stems.Level of EvidenceLevel III; Retrospective Cohort Comparative Study     

Femoral prosthesis neck fracture following total hip arthroplasty: a case report

Fracture of the femoral prosthesis neck following total hip arthroplasty is not common. We report a case of femoral prosthesis neck fracture in an adult male patient following modular, uncemented total hip arthroplasty. This case report further emphasizes the importance of the potentially high loading situation in the prosthetic femoral neck. On the other hand, the occurrence of a femoral prosthesis neck fracture in a cementless system denotes a well fixed distal stem and calls for a difficult revision procedure usually requiring an extended trochanteric osteotomy for stem retrieval.     

Bone Grafting Severe Glenoid Defects in Revision Shoulder Arthroplasty

During revision total shoulder arthroplasty, bone grafting severe glenoid defects without concomitant reinsertion of a glenoid prosthesis may be the only viable reconstructive option. However, the fate of these grafts is unknown. We questioned the durability and subsidence of the graft and the associated clinical outcomes in patients who have this procedure. We retrospectively reviewed 11 patients with severe glenoid deficiencies from aseptic loosening of a glenoid component who underwent conversion of a total shoulder arthroplasty to a humeral head replacement and glenoid bone grafting. Large cavitary defects were grafted with either allograft cancellous chips or bulk structural allograft, depending on the presence or absence of glenoid vault wall defects, without prosthetic glenoid resurfacing. Clinical outcomes (Penn Shoulder Score, maximum 100 points) improved from 23 to 57 at a minimum 2-year followup (mean, 38 months; range, 24-73 months). However, we observed substantial graft subsidence in all patients, with eight of 11 patients having subsidence greater than 5 mm; the magnitude of graft resorption did not correlate with clinical outcome scores. Greater subsidence was seen with structural than cancellous chip allografts. Bone grafting large glenoid defects during revision shoulder arthroplasty can improve clinical outcome scores, but the substantial resorption of the graft material remains a concern. LEVEL OF EVIDENCE: Level III Prognostic study.     

Numeral component revision of totalelbow arthroplasty with numeral bone deficiency

Elbow arthroplasty is often effective in decreasing pain and restoring elbow function for individuals with a painfulelbow from rheumatoid arthritis, severe osteoarthritis, tumors, and comminuted intra-articular fractures. Because the surgical procedure has now been performed on many patients, revision of the prosthesis is sometimes required. If there is loss of distal humeral bone, revision surgery becomes more of a challenge because fixation of the prosthesis may be compromised, arm length may not be restored, and risk of neurologic injury is greater. In this article, we address these issues and report our technique of humeral component revision of total elbow arthroplasty with massive allograft bone and a long-stem prosthesis.     

非骨水泥长柄假体在髋关节翻修术中的应用

目的回顾性分析非骨水泥全涂层长柄假体在全髋关节翻修术中应用的临床疗效。方法对2006年1月至2011年1月四川大学华西医院收治的采用全涂层长柄假体全髋关节翻修术的53例患者（53髋）进行随访、分析。其中男26例,女27例;年龄49—78岁,平均62岁。股骨假体采用强生（Depuy）公司全涂层长度为165mm的直柄AML假体10例、全涂层165mm的Solution假体19例和203mm带弧度分左右侧的Solution假体24例。比较髋关节术前术后的Harris评分,x线片评价假体柄有无松动下沉及应力遮挡情况。结果53例患者均获随访,随访时间1．8～6．8年,平均4．7年。术前平均Harris评分为37分,最后随访时增加至86分。所有患者均在术后3个月后完全负重,原有髋关节疼痛缓解。在最后随访时,有45例股骨柄假体获得骨长人固定。并发症：术后脱位1例,手法复位后未再发生脱位,术后感染1例,假体柄明显下沉1例,后两例患者行再次翻修术,末次随访假体柄稳定。随访X线片显示多数患者骨质改建,密度增加,未发现假体周围有连续亮带及假体柄下沉的患者。结论复杂的股骨侧翻修手术,应尽可能选择非骨水泥长柄假体。特别是股骨干骺端骨质条件差,中段有骨缺损,近端不能获得牢固固定的病例。术中结合同种异体颗粒骨打压植骨处理股骨中上段中重度骨缺损,中期临床疗效良好,远期效果有待随访。