Revision knee arthroplasty with a rotating-hinge design in elderly patients with instability following total knee arthroplasty

Background

Revision knee arthroplasty with a rotating-hinge design could be an option for the treatment of instability following total knee arthroplasty (TKA) in elderly patients.

Purpose

To evaluate the clinical and radiographic results of revision arthroplasties in TKAs with instability using a rotating-hinge design in elderly patients.

Methods

We retrospectively reviewed 96 rotating-hinge arthroplasties. The average age of the patients was 79 years (range, 75–86 years); the minimum follow-up was 5 years (mean, 7.3 years; range, 5–10 years). Patients were evaluated clinically (Knee Society score) and radiographically (position of prosthetic components, signs of loosening, bone loss).

Results

At a minimum followup of 5 years (mean, 7.3 years; range, 5–10 years), Knee Society pain scores improved from 37 preoperatively to 79 postoperatively, and function scores improved from 34 to 53. ROM improved on average from −15° of extension and 80° of flexion before surgery to −5° of extension and 120° of flexion at the last followup (p = 0.03). No loosening of implants was observed. Nonprogressive radiolucent lines were identified around the femoral and tibial components in 2 knees. One patient required reoperation because of a periprosthetic infection.

Conclusions

Revision arthroplasty with a rotating-hinge design provided substantial improvement in function and a reduction in pain in elderly patients with instability following TKA.

Level of evidence

Level IV, therapeutic study.     

Bicruciate-retaining Total Knee Replacement Provides Satisfactory Function and Implant Survivorship at 23?Years

Background

One of the goals of a TKA is to approximate the function of a normal knee. Preserving the natural ligaments might provide a method of restoring close to normal function. Sacrifice of the ACL is common and practical during a TKA. However, this ligament is functional in more than 60% of patients undergoing a TKA and kinematic studies support the concept of bicruciate-retaining (that is, ACL-preserving) TKA; however, relatively few studies have evaluated patients treated with bicruciate-retaining TKA implants.

Questions/purposes

I asked: (1) what is the long-term (minimum 20-year) survivorship, (2) what are the functional results, and (3) what are the reasons for revision of bicruciate-retaining knee arthroplasty prostheses?

Methods

From January 1989 to September 1992, I performed 639 total knee replacements in 537 patients. Of these, 489 were performed in 390 patients using a bicruciate-retaining, minimally constrained device. During the period in question, this knee prosthesis was used for all patients observed intraoperatively to have an intact, functional ACL with between 15° varus and 15° valgus joint deformity. There were 234 women and 156 men with a mean age at surgery of 65 years (range, 42–84 years) and a primary diagnosis of osteoarthritis in 89%. The patella was resurfaced in all knees. The mean followup was 23 years (range, 20–24 years). At the time of this review, 199 (51%) patients had died and 31 (8%) patients were lost to followup, leaving 160 (41%) patients (214 knees) available for review. Component survivorship was determined by competing-risks analysis and Kaplan Meier survivorship analysis with revision for any reason as the primary endpoint. Patients were evaluated every 2 years to assess ROM, joint laxity, knee stability, and to determine American Knee Society scores.

Results

The Kaplan-Meier survivorship was 89% (95% CI, 82%–93%) at 23 years with revision for any reason as the endpoint. Competing-risks survivorship was 94% (95% CI, 91%%–96 %) at 23 years. At followup, the mean age of the patients was 84 years (range, 63–101 years), the mean flexion was 117° (range, 90°–130°), the mean American Knee Society score improved from a preoperative mean of 42 (range, 26–49) to 91 (range, 61–100; p < .001). Twenty-two knees in 21 patients (5.6%) were revised, most commonly because of polyethylene wear.

Conclusions

ACL sacrifice may be an unnecessary concession during TKA. This study found satisfactory survivorship and function after more than 20 years of use for patients receiving a bicruciate-retaining TKA implant. A TKA that preserves cruciate ligaments provides a stable, well-functioning knee with a low likelihood of revision at long-term followup. Retaining both cruciate ligaments during knee arthroplasty is an attractive concept that is worth considering.

Level of Evidence

Level IV, therapeutic study.     

The Use of Tantalum Metaphyseal Cones for the Management of Severe Bone Defects in Septic Knee Revision

Background

Femoral and tibial massive bone defects are common findings in septic total knee revision and pose considerable challenges for the orthopedic surgeon. The aim of this study was to report the midterm clinical and radiographic outcomes with the use of tantalum cones for the management of massive bone defects after 2-stage knee revision.

Two-Stage Revision for Infected Total Knee Arthroplasty: Based on Autoclaving the Recycled Femoral Component and Intraoperative Molding Using Antibiotic-Impregnated Cement on the Tibial Side

Background

The purpose of this study was to determine the degree of infection control and postoperative function for new articulating metal-on-cement spacer.

Methods

A retrospective study of 19 patients (20 cases), who underwent a two-stage revision arthroplasty using mobile cement prosthesis, were followed for a minimum of 2 years. This series consisted of 16 women and 3 men, having an overall mean age of 71 years. During the first stage of revision, the femoral implant and all the adherent cement was removed, after which it was autoclaved before replacement. The tibial component was removed and a doughy state, antibiotic-impregnated cement was inserted on the tibial side. To achieve joint congruency, intraoperative molding was performed by flexing and extending the knee joint. Each patient was evaluated clinically and radiologically. The clinical assessments included range of motion, and the patients were scored as per the Hospital for Special Surgery (HSS) and Knee Society (KS) criteria.

Results

The mean range of knee joint motion was 70° prior to the first stage operation and 72° prior to the second stage revision arthroplasty; following revision arthroplasty, it was 113° at the final follow-up. The mean HSS score and KS knee and function scores were 86, 82, and 54, respectively, at the final follow-up. The success rate in terms of infection eradication was 95% (19/20 knees). No patient experienced soft tissue contracture requiring a quadriceps snip.

Conclusions

This novel technique provides excellent radiological and clinical outcomes. It offers a high surface area of antibiotic-impregnated cement, a good range of motion between first and second stage revision surgery for the treatment of chronic infection after total knee arthroplasty, and is of a reasonable cost.     

The impact of joint line restoration on functional results after hinged knee prosthesis

Background:

Hinged knee prosthesis is an effective treatment method as a salvage procedure in marked ligamentous insufficiency and severe bone defects. Joint line determination and restoration are difficult due to large bone defects and distorted anatomy. We evaluated the impact of joint line alteration on the outcome in rotating hinge knee arthroplasty (RHKA).

Materials and Methods:

35 patients who had rotating hinged knee prosthesis applied between 2008 and 2013 were evaluated in this retrospective study. The patients were studied radiologically and clinically. Five patients were lost to followup and two patients died, leaving a total of 28 (7 male, 21 female) patients for final evaluation. The average age of the patients was 66.19 ± 8.35 years (range 52–83 years). The patients were evaluated clinically with Knee Society knee and functional score and patellar score. The joint line positions were evaluated radiographically with femoral epicondylar ratio method. The outcomes were also evaluated according to age, body weight and gender. Student''s t-test, independent t-test, and the Wilcoxon signed rank test were used in the statistical analysis.

Results:

The mean Knee Society knee and functional score significantly improved from preoperative 19.52 ± 11.77 and 12.5 ± 15.66 respectively to 72.46 ± 14.01 and 70.36 ± 9.22 respectively postoperatively (P < 0.001). The mean range of motion of the knee improved from 55.95° ± 25.08° preoperatively to 92.14° ± 13.47° postoperatively (P < 0.001). Joint line position was restored in 20 patients (71.4%). Joint line alteration did not affect Knee Society Scores (KSSs) in contrast to patellar scores. Additionally, KSS was better in the patients with body mass index ≤30 at followup (P = 0.022 and P = 0.045).

Conclusion:

RHKA is an effective salvage procedure for serious instability and large bone defects. Restoration of the joint line improves the patellar score although it had no effect on the clinical outcome.     

Kaplan-Meier Survival Analysis Overestimates the Risk of Revision Arthroplasty: A Meta-analysis

Background

Although Kaplan-Meier survival analysis is commonly used to estimate the cumulative incidence of revision after joint arthroplasty, it theoretically overestimates the risk of revision in the presence of competing risks (such as death). Because the magnitude of overestimation is not well documented, the potential associated impact on clinical and policy decision-making remains unknown.

Questions/purposes

We performed a meta-analysis to answer the following questions: (1) To what extent does the Kaplan-Meier method overestimate the cumulative incidence of revision after joint replacement compared with alternative competing-risks methods? (2) Is the extent of overestimation influenced by followup time or rate of competing risks?

Methods

We searched Ovid MEDLINE, EMBASE, BIOSIS Previews, and Web of Science (1946, 1980, 1980, and 1899, respectively, to October 26, 2013) and included article bibliographies for studies comparing estimated cumulative incidence of revision after hip or knee arthroplasty obtained using both Kaplan-Meier and competing-risks methods. We excluded conference abstracts, unpublished studies, or studies using simulated data sets. Two reviewers independently extracted data and evaluated the quality of reporting of the included studies. Among 1160 abstracts identified, six studies were included in our meta-analysis. The principal reason for the steep attrition (1160 to six) was that the initial search was for studies in any clinical area that compared the cumulative incidence estimated using the Kaplan-Meier versus competing-risks methods for any event (not just the cumulative incidence of hip or knee revision); we did this to minimize the likelihood of missing any relevant studies. We calculated risk ratios (RRs) comparing the cumulative incidence estimated using the Kaplan-Meier method with the competing-risks method for each study and used DerSimonian and Laird random effects models to pool these RRs. Heterogeneity was explored using stratified meta-analyses and metaregression.

Results

The pooled cumulative incidence of revision after hip or knee arthroplasty obtained using the Kaplan-Meier method was 1.55 times higher (95% confidence interval, 1.43–1.68; p < 0.001) than that obtained using the competing-risks method. Longer followup times and higher proportions of competing risks were not associated with increases in the amount of overestimation of revision risk by the Kaplan-Meier method (all p > 0.10). This may be due to the small number of studies that met the inclusion criteria and conservative variance approximation.

Conclusions

The Kaplan-Meier method overestimates risk of revision after hip or knee arthroplasty in populations where competing risks (such as death) might preclude the occurrence of the event of interest (revision). Competing-risks methods should be used to more accurately estimate the cumulative incidence of revision when the goal is to plan healthcare services and resource allocation for revisions.     

Outcome of Total Knee Arthroplasty After High Tibial Osteotomy: Does Malalignment Jeopardize the Results when Using a Posterior-Stabilized Arthroplasty?

Background

The controversy regarding the outcome of total knee arthroplasties after high tibial osteotomy may relate to malalignment secondary to overcorrection after high tibial osteotomy (HTO) [1, 2] and to the type of arthroplasty itself (posterior-stabilized arthroplasty or posterior cruciate ligament-retaining prosthesis).

Questions/Purpose

We asked two questions: (1) Would a posterior-stabilized arthroplasty provide sufficient constrain and improve pain and function in patients with severe malalignment due to a previous HTO? (2) Will malalignment of the previous HTO jeopardize the long-term results of a total knee reconstruction with a posterior-stabilized implant?

Patients and Methods

We retrospectively reviewed 25 posterior-stabilized TKAs in 25 patients with severe valgus deformity after HTO (ranging from 10° to 20° of valgus) and compared the results with a series of matched 25 posterior-stabilized TKAs in 25 patients with normocorrection after HTO ranging from 5° of valgus to 5° of varus. Clinical, operative, and radiographic data were reviewed. Minimum follow-up was 10 years after the arthroplasty (average, 15 years; range, 10–20 years).

Results

All the knees had standard posterior-stabilized total knee arthroplasty implants. Patients with an overcorrected HTO were more likely to require a soft tissue release to balance the knee. However, Average Knee Society and Function Score improved, respectively, from 48 to 85 and from 50 to 90 points in the severely overcorrected group, versus, respectively, 50 to 89 and 52 to 97 in the normocorrected group, but the range of mobility was superior for patients with normal alignment. Fifteen-year survivorship after the arthroplasty comparison showed no significant difference between the two groups (one revision in each group).

Conclusions

Patients with an overcorrected HTO are more likely to require a soft tissue release to balance the knee. However, both groups show improvements in function and pain. With a posterior-stabilized arthroplasty, the degree of deformity has no impact on the longevity of the TKA.

Electronic supplementary material

The online version of this article (doi:10.1007/s11420-013-9344-x) contains supplementary material, which is available to authorized users.     

Results of Revision Surgery and Causes of Unstable Total Knee Arthroplasty

Background

The aim of this study was to evaluate causes of unstable total knee arthroplasty and results of revision surgery.

Methods

We retrospectively reviewed 24 knees that underwent a revision arthroplasty for unstable total knee arthroplasty. The average follow-up period was 33.8 months. We classified the instability and analyzed the treatment results according to its cause. Stress radiographs, postoperative component position, and joint level were measured. Clinical outcomes were assessed using the Hospital for Special Surgery (HSS) score and range of motion.

Results

Causes of instability included coronal instability with posteromedial polyethylene wear and lateral laxity in 13 knees, coronal instability with posteromedial polyethylene wear in 6 knees and coronal and sagittal instability in 3 knees including post breakage in 1 knee, global instability in 1 knee and flexion instability in 1 knee. Mean preoperative/postoperative varus and valgus angles were 5.8°/3.2° (p = 0.713) and 22.5°/5.6° (p = 0.032). Mean postoperative α, β, γ, δ angle were 5.34°, 89.65°, 2.74°, 6.77°. Mean changes of joint levels were from 14.1 mm to 13.6 mm from fibular head (p = 0.82). The mean HSS score improved from 53.4 to 89.2 (p = 0.04). The average range of motion was changed from 123° to 122° (p = 0.82).

Conclusions

Revision total knee arthroplasty with or without a more constrained prosthesis will be a definite solution for an unstable total knee arthroplasty. The solution according to cause is very important and seems to be helpful to avoid unnecessary over-constrained implant selection in revision surgery for total knee instability.     

High Survivorship With Cementless Stems and Cortical Strut Allografts for Large Femoral Bone Defects in Revision THA

Background

Numerous studies have investigated the clinical and radiographic results of revision THAs with use of cementless stems and cortical strut allografts. However, to our knowledge, no long-term followup studies have evaluated patients undergoing revision THA with use of cortical strut allografts where the allografts provided the primary stability for extensively coated femoral stems in the presence of extensive femoral diaphyseal bone defects.

Question/purposes

We performed this study to determine (1) validated outcomes scores; (2) radiographic signs of fixation and allograft healing; (3) frequency of complications; and (4) survivorship of the components after use of cortical strut onlay allografts in Types IIIB and IV femoral diaphyseal bone defects.

Methods

Between 1994 and 2003, we performed 140 revision THAs in 130 patients with Paprosky Types IIIB and IV femoral diaphyseal defects. The patients were treated using extensively coated femoral stems and cortical strut allografts because primary axial or rotational stability could not be achieved without grafting. Ten of the patients (10 hips; 7.7%) were lost to followup or died before 10 years; the remaining 120 patients (130 hips) represent the study group in this retrospective study. There were 66 men and 54 women. Their mean age at the time of index surgery was 59 ± 18 years (range, 36–67 years). The primary diagnosis was predominantly osteonecrosis of the femoral head (53%). The most common reason for revision was aseptic loosening (97%), followed by periprosthetic fracture (3%). The mean time from primary to revision THA was 12 years (range, 8–27 years). The mean duration of followup was 16.1 years (range, 12–20 years).

Results

The mean Harris hip score was 39 ± 10 points before revision and improved to 86 ± 14 points at 16 years followup (p = 0.02). The mean preoperative WOMAC score was 62 ± 29 (41–91) points and improved to 22 ± 19 (11–51) points at 16 years followup (p = 0.003). Of the 130 stems, 113 (87%) had bone ingrowth, five (4%) had stable fibrous ingrowth, and 12 (9%) were unstable. All allografts were incorporated. Four hips (3%) had a displaced femoral shaft fracture at the stem tip; four (3%) had a postoperative dislocation; and six (5%) had early postoperative infection. Kaplan-Meier survivorship analysis, with revision or radiographic failure as the endpoint, revealed that the 16-year rate of survival of the components was 91% (95% CI, 0.88%–0.96%).

Conclusion

Supportive cortical strut onlay allografts provided high survivorship beyond 12 years of followup in revision THAs. Future studies might compare this approach with allograft-prosthesis composites, proximal femoral replacement, or modular fluted, tapered stems.

Level of Evidence

Level IV, therapeutic study.     

Satisfying Outcomes Scores and Survivorship Achieved With Impaction Grafting for Revision THA in Young Patients

Background

The increasing number of total hip arthroplasties (THAs) performed in younger patients will inevitably generate larger numbers of revision procedures for this specific group of patients. Unfortunately, no satisfying revision method with acceptable survivorship 10 years after revision has been described for these patients so far.

Questions/purposes

The purposes of this study were to (1) analyze the clinical outcome; (2) complication rate; (3) survivorship; and (4) radiographic outcome of cemented revision THA performed with impaction bone grafting (IBG) on both the acetabular and femoral sides in one surgery in patients younger than 55 years old.

Methods

During the period 1991 to 2007, 86 complete THA revisions were performed at our institution in patients younger than 55 years. In 34 of these 86 revisions (40%), IBG was used on both the acetabular and femoral sides in 33 patients. Mean patient age at revision surgery was 46.4 years (SD 7.6). No patient was lost to followup, but three patients died during followup. None of the deaths were related to the revision surgery. The mean followup for the surviving hips was 11.7 years (SD 4.6). We also analyzed complication rate.

Results

The mean Harris hip score improved from 55 (SD 18) preoperatively to 80 points (SD 16) at latest followup (p = 0.009). Six hips underwent a rerevision (18%): in four patients, both components were rerevised; and in two hips, only the cup was revised. Patient 10-year survival rate with the endpoint of rerevision for any component for any reason was 87% (95% confidence interval [CI], 67%–95%) and with the endpoint of rerevision for aseptic loosening, the survival rate was 97% (95% CI, 80%–100%). In total six cups were considered radiographically loose, of which four were rerevised. Three stems were radiographically loose, of which none was rerevised.

Conclusions

IBG is a valuable biological revision technique that may restore bone stock in younger patients. Bone stock reconstruction is important, because these patients likely will outlive their revision implants. Bone reconstruction with impaction grafting may facilitate future revisions.

Level of Evidence

Level IV, therapeutic study.     

Do Porous Tantalum Metaphyseal Cones Improve Outcomes in Revision Total Knee Arthroplasty?

Background

Some authors have advocated for use of porous tantalum metaphyseal cones to manage bone defects during revision total knee arthroplasty (TKA). The purpose of this study is to compare results with porous metaphyseal cones to results with traditional hybrid stem fixation in revision TKA.

Bone mineral density changes of the proximal tibia after revision total knee arthroplasty. A randomised study with the use of porous tantalum metaphyseal cones

Purpose

Forty patients were enrolled in a prospective randomised study using conventional method or “Trabecular Metal Cone” (TM Cone) (Zimmer inc., Warsaw, USA) for reconstruction of bone loss of the proximal tibia during revision total knee arthroplasty (rTKA). The aim was to evaluate changes in bone mineral density (BMD) at the proximal tibia.

Material and methods

Thirty-six patients [median 67 years (range: 40–85 years)] received rTKA with NexGen® (Zimmer Warsaw, USA) revision system. Knee Society´s Knee Scoring System and the Anderson Orthopaedic Research Institute (AORI) bone classification was used. Changes in BMD were measured by dual energy X-ray absorptiometry (DEXA).

Results

Knee and function score improved in both groups. No significant changes between the groups were found. Changes in BMD within the two groups were quite similar. Overall decreases in BMD of 0.1 - 5.4 % were found in both groups (ROI 1–6) postoperative to 12 months of follow-up, except that ROI 7 showed an increase in BMD (0.8 - 1.3 %). After 24 months of follow-up, an increase in BMD was found along the stem (ROI 2–5) of 1.9 - 6.3 % , with significant changes in the TM Cone Group (ROI 3, 4, 5) . No significant changes in BMD between the groups were found.

Conclusions

The bone remodelling pattern was almost the same in the two groups after two years.     

Subchondral Calcium Phosphate is Ineffective for Bone Marrow Edema Lesions in Adults With Advanced Osteoarthritis

Background

Injury to subchondral bone is associated with knee pain and osteoarthritis (OA). A percutaneous calcium phosphate injection is a novel approach in which subchondral bone marrow edema lesions are percutaneously injected with calcium phosphate. In theory, calcium phosphate provides structural support while it is gradually replaced by bone. However, little clinical evidence supports the efficacy of percutaneous calcium phosphate injections.

Questions/purposes

We asked: (1) Does percutaneous calcium phosphate injection improve validated patient-reported outcome measures? (2) What proportion of patients experience failure of treatment (defined as a low score on the Tegner Lysholm Knee Scoring Scale)? (3) Is there a relationship between outcome and age, sex, BMI, and preoperative grade of OA?

Methods

Between September 2012 and January 2014, we treated 33 patients with percutaneous calcium phosphate injections. Twenty-five satisfied our study inclusion criteria; of those, three patients were lost to followup and 22 (88%; 13 men, nine women) with a median age of 53.5 years (range, 38–70 years) were available for retrospective chart review and telephone evaluation at a minimum of 6 months (median, 12 months; range, 6–24 months). Our general indications for this procedure were the presence of subchondral bone marrow edema lesions observed on MR images involving weightbearing regions of the knee associated with localized pain on weightbearing and palpation and failure to respond to conservative therapy (> 3 months). Patients with pain secondary to extensive nondegenerative meniscal tears with a flipped displaced component at the level of bone marrow edema lesions, or with mechanical axis deviation greater than 8° were excluded. All patients had Grades III or IV chondral lesions (modified Outerbridge grading system for chondromalacia) overlying MRI-identified subchondral bone marrow edema lesions. Percutaneous calcium phosphate injection was performed on the medial tibial condyle (15 patients), the medial femoral condyle (five patients), and the lateral femoral condyle (two patients). Concomitant partial meniscectomy was performed in 18 patients. Preoperative and postoperative scores from the Knee Injury and Arthritis Outcome Score (KOOS) and the Tegner Lysholm Knee Scoring Scale were analyzed.

Results

For patients available for followup, the outcome scores improved after treatment. The KOOS improved from a mean of 39.5 ± 21.8 to 71.3 ± 23 (95% CI, 18.6–45.2; p < 0.001) and the Tegner and Lysholm score from 48 ± 15.1 to 77.5 ± 20.6 (95% CI, 18.8–40.2; p < 0.001). However, seven of the 22 patients had poor clinical outcomes as assessed by the Tegner Lysholm Knee Scoring Scale, whereas three had fair results, five had good results, and seven had excellent results. The postoperative Tegner Lysholm score was inversely related to the preoperative Kellgren-Lawrence OA grade (R² = 0.292; F (1.20) = 9.645; p = 0.006). We found no relationship between outcome scores and age, sex, or BMI.

Conclusions

In a study that would have been expected to present a best-case analysis (short-term followup, loss to followup of patients with potentially unsatisfactory results, and use of invasive cotreatments including arthroscopic débridements), we found that percutaneous calcium phosphate injection in patients with symptomatic bone marrow edema lesions of the knee and advanced OA yielded poor results in a concerning proportion of our patients. Based on these results, we advise against the use of percutaneous calcium phosphate injections for patients with advanced osteoarthritic changes.

Level of Evidence

Level IV, therapeutic study.     

Are Custom Triflange Acetabular Components Effective for Reconstruction of Catastrophic Bone Loss?

Background

Although the introduction of ultraporous metals in the forms of acetabular components and augments has increased the orthopaedic surgeon’s ability to reconstruct severely compromised acetabuli, there remain some that cannot be managed readily using cups, augments, or cages. In such situations, allograft-prosthetic composites or custom acetabular components may be called for. However, few studies have reported on the results of these components.

Questions/purposes

The purposes of this study were to determine the (1) frequency of repeat revision, (2) complications and radiographic findings, and (3) Harris hip scores in patients who underwent complex acetabular revision surgery with custom acetabular components.

Methods

Between August 2003 and February 2012, 26 patients (28 hips) have undergone acetabular reconstruction with custom triflange components. During this time, the general indications for using these implants included (1) failed prior salvage reconstruction with cage or porous metal construct augments, (2) large contained defects with possible discontinuity, (3) known pelvic discontinuity, and (4) complex multiply surgically treated hips with insufficient bone stock to reconstruct using other means. This approach was used in a cohort of patients with Paprosky Type 3B acetabular defects, which represented 3% (30 of 955) of the acetabular revisions we performed during the study period. Minimum followup was 2 years (mean, 57 months; range, 28–108 months). Seven patients (eight hips) died during the study period, and three (11%) of these patients (four hips; 14%) were lost to followup before 2 years, leaving 23 patients (24 hips) with minimum 2-year followup. Sixteen patients were women. The mean age of the patients was 67 years (range, 47–85 years) and mean BMI was 28 kg/m² (range, 23–39 kg/m²). Revisions and complications were identified by chart review; hip scores were registered in our institution’s longitudinal database. Pre- and postoperative radiographs were analyzed by the patient’s surgeon to determine whether migration, fracture of fixation screws, or continued bone loss had occurred.

Results

There have been four subsequent surgical interventions: two failures secondary to sepsis, and one stem revision and one open reduction internal fixation for periprosthetic femoral fracture. There were two minor complications managed nonoperatively, but all of the components were noted to be well-fixed with no obvious migration or loosening observed on the most recent radiographs. Harris hip scores improved from a mean of 42 (SD, ± 16) before surgery to 65 (SD, ± 18) at latest followup (p < 0.001).

Conclusions

Custom acetabular triflange components represent yet another tool in the reconstructive surgeon’s armamentarium. These devices can be helpful in situations of catastrophic bone loss.

Level of Evidence

Level IV, therapeutic study.     

Conversion of Stemmed Hemi- or Total to Reverse Total Shoulder Arthroplasty: Advantages of a Modular Stem Design

Background

If revision of a failed anatomic hemiarthroplasty or total shoulder arthroplasty is uncertain to preserve or restore satisfactory rotator cuff function, conversion to a reverse total shoulder arthroplasty has become the preferred treatment, at least for elderly patients. However, revision of a well-fixed humeral stem has the potential risk of loss of humeral bone stock, nerve injury, periprosthetic fracture, and malunion or nonunion of a humeral osteotomy with later humeral component loosening.

Questions/purposes

The purposes of this study were to determine whether preservation of a modular stem is associated with (1) less blood loss and operative time; (2) fewer perioperative and postoperative complications, including reoperations and revisions; and/or (3) improved Constant and Murley scores and subjective shoulder values for conversion to a reverse total shoulder arthroplasty compared with stem revision.

Methods

Between 2005 and 2011, 48 hemiarthroplasties and eight total shoulder arthroplasties (total = 56 shoulders; 54 patients) were converted to an Anatomical™ reverse total shoulder arthroplasty system without (n = 13) or with (n = 43) stem exchange. Complications and revisions for all patients were tallied through review of medical and surgical records. The outcomes scores included the Constant and Murley score and the subjective shoulder value. Complete clinical followup was available on 80% of shoulders (43 patients; 45 of 56 procedures, 32 with and 13 without stem exchange) at a minimum of 12 months (mean, 37 months; range, 12–83 months).

Results

Blood loss averaged 485 mL (range, 300–700 mL; SD, 151 mL) and surgical time averaged 118 minutes (range, 90–160 minutes; SD, 21 minutes) without stem exchange and 831 mL (range, 350–2000 mL; SD, 400 mL) and 176 minutes (range, 120–300 minutes; SD, 42 minutes) with stem exchange (p = 0.001). Intraoperative complications (8% versus 30%; odds ratio [OR], 5.2) and reinterventions (8% versus 14%; OR, 1.9) were substantially fewer in patients without stem exchange. The complication rate leading to dropout from the study was substantial in the stem revision group (six patients; 43 shoulders [14%]), but there were no complication-related dropouts in the stem-retaining group. If, however, such complications could be avoided, with the numbers available we detected no difference in the functional outcome between the two groups.

Conclusions

Patients undergoing revision of stemmed hemiarthroplasty or total to reverse total shoulder arthroplasty without stem exchange had less intraoperative blood loss and operative time, fewer intraoperative complications, and fewer revisions than did patients whose index revision procedures included a full stem exchange. Therefore modularity of a shoulder arthroplasty system has substantial advantages if conversion to reverse total shoulder arthroplasty becomes necessary and should be considered as prerequisite for stemmed shoulder arthroplasty systems.

Level of Evidence

Level III, therapeutic study.