Progressive Radiolucent Lines Research Articles

A ten-year radiologic comparison of two-all polyethylene glenoid component designs: a prospective trial

Aseptic glenoid component loosening remains a common problem in total shoulder arthroplasty (TSA). This study presents long-term prospective follow-up of 2 cemented all-polyethylene glenoid components with different backside design geometry and the effect on the presence and progression of radiolucent lines (RLLs). Fifty-six TSAs were performed for primary osteoarthritis. Two surgeons used an identical technique to implant 32 flat-back and 24 convex-back glenoids. In particular, the glenoid components were cemented after a minimal reaming and bone compaction. Standardized postoperative radiologic and clinical follow-up was at 2 and 10 years. Three independent observers evaluated the x-ray images for RLLs around the base plate and keel. The results were analyzed for progression and influencing factors. At 10 years, progression of RLL was seen in both components, but there was no difference between the 2 glenoid designs (P = .16). Younger patient age (P = .03), hand dominance (P = .017), and presence of early RLLs (P = .018) were significant factors for progression of RLLs. Constant scores deteriorated with progression of RLLs (P = .006). The glenoid revision rate at 10 years was 5%. At 10 years there was no difference in the presence or progression of RRLs between a flat-back and a convex-back glenoid all-polyethylene design. Young age, hand dominance, and poor implantation technique influence glenoid RLLs and affect the clinical result of TSA.

Surgical Technique: Porous Tantalum Reconstruction for Destructive Nonprimary Periacetabular Tumors

Large bone loss and frequently irradiated existing bone make reconstructing metastatic and other nonprimary periacetabular tumors challenging. Although existing methods are initially successful, they may fail with time. Given the low failure rates of porous tantalum acetabular implants in other conditions with large bone loss or irradiated bone, we developed a technique to use these implants in these neoplastic cases where others might fail. After local tumor curettage, a large uncemented tantalum shell (sometimes with tantalum augments) was fixed to remaining bone using numerous screws. When substantial medial bone loss was present, an antiprotrusio cage was placed over the top of the cup and secured to remaining ilium and ischium. We retrospectively reviewed 20 patients who underwent THAs for neoplastic bone destruction with the described technique. Their mean age was 60 years (range, 22-80 years). We recorded pain and ambulatory status, pain medication use, and Harris hip scores. We assessed for progressive radiolucent lines and component migration on followup radiographs. Eleven of the 20 patients died at a mean of 17 months after surgery. The minimum followup for surviving patients was 26 months (mean, 56 months; range, 26-85 months). Harris hip scores improved from a mean 32 preoperatively to a mean 74 postoperatively. We observed no cases of progressive radiolucent lines or component migration. Complications included one perioperative death, two superficial infections, one deep vein thrombosis, and one dislocation. Our initial experience has made tantalum reconstruction our preferred method for dealing with major periacetabular neoplastic bone loss. Additional studies comparing this technique with alternatives are required. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

High-Flexion versus Conventional Total Knee Arthroplasty: A 5-Year Study

To compare mid-term outcomes of a high-flexion prosthesis with a conventional prosthesis. Records of 107 consecutive patients who underwent total knee arthroplasty (TKA) for primary osteoarthritis by a single surgeon were reviewed. 21 men and 36 women (mean age, 65 years) used a high-flexion prosthesis (NexGen CR-Flex Mobile, Zimmer), whereas 38 men and 12 women (mean age, 67 years) used a conventional prosthesis (Genesis II, Smith & Nephew) that preserves the posterior cruciate ligament, with mobile-bearing polyethylene inlay. The Knee Society knee and functional scores and the range of motion (especially maximum passive flexion) were assessed. Radiographs were evaluated to identify radiolucent lines at the bone cement interface, patella tracking, tibiofemoral alignment, and implant positioning. The mean follow-up period was 68 (range, 51- 70) months. In terms of the mean Knee Society scores and range of motion, the difference between groups was not significant (p>0.05), but the improvement in both groups after TKA was significant (p<0.005). Respectively in the high-flexion and conventional TKA groups, 2 and one of the patients developed deep vein thrombosis and were treated with anticoagulants for 3 months. One and 5 of the patients had an unsatisfactory range of motion (<60º) in week 1, which was resolved with mobilisation under general anaesthesia in combination with a peridural catheter for analgesia. No patient developed implant-specific complications such as aseptic loosening (osteolysis, progressive radiolucent lines, implant deviation) or dislocation of the polyethylene insert. The high-flexion prosthesis revealed no significant advantages over the conventional prosthesis in terms of the Knee Society scores and range of motion. Long-term studies are needed to determine whether the high-flexion implant is superior to the conventional implant in terms of polyethylene wear and aseptic loosening.

Cemented fixed-bearing PFC total knee arthroplasty: survival and failure analysis at 12–17 years

BackgroundTotal knee arthroplasty (TKA) is the appropriate treatment for degenerative pathology of the knee. Implant surveillance is mandatory to improve clinical results. We present the long-term results of a series of consecutive TKA Press Fit Condylar (J&J), cemented fixed bearing with selective patellar resurfacing in nonselected patients.Materials and methodsIn this prospective case series, 223 TKA were clinically and radiographically evaluated using the Hospital for Special Surgery (HSS) knee score and the Knee Society Roentgenographic Evaluation and Scoring System.ResultsThere were 197 patients, with an average age of 68.4 years [95% confidence interval (CI) 52.7–84.1 years]; 49 arthroplasties were implanted in men (21.1%) and 184 (78.9%) in women. The average follow-up was approximately 13.5 years (162.1 months; 95% CI 132.3–191.9), and it was possible to evaluate 179 implants (76.8% of the implanted prosthesis) in 176 patients. The average HSS score increased from 61.5 (95% CI 60.4–62.7) to 89.4 (95% CI 87.7–.93.5) points. The cumulative average survival rate at 15 years (the endpoint being failure with revision) was 90.6% ± 2% standard deviation. Resurfacing the patella did not make a difference in terms of implant survival. Progressive radiolucent lines were observed around 20 implants (14.3%); all were revised.ConclusionsThe PFC system is an excellent prosthetic solution. Early clinical complications, mechanical axis and patellar resurfacing do not correlate with implant failure, whereas progressive radiolucent lines do.

Cementless Modular Total Hip Arthroplasty with Subtrochanteric Shortening Osteotomy for Hips with Developmental Dysplasia

The purpose of this retrospective study was to analyze the functional and radiographic results of cementless, modular total hip arthroplasty combined with subtrochanteric osteotomy for the treatment of patients who had had Crowe Group-IV developmental dysplasia of the hip as a child. Twenty-five consecutive patients (thirty-three hips) who had previously had Crowe Group-IV developmental dysplasia of the hip were treated with a modular cementless prosthesis at a mean age of sixty years. The mean follow-up period was eight years (range, five to eleven years). The acetabular cup was placed in the position of the anatomical hip center in every patient. Subtrochanteric femoral shortening osteotomy was performed with use of a step-cut design. The mean Merle d'Aubigné and Postel hip score improved from 9 to 16 points (out of a maximum of 18 points). The mean limb-length discrepancy in seventeen patients with unilateral involvement was reduced from 5.1 cm (range, 3.7 to 6.5 cm) to 2.8 cm (range, 1.4 to 4.6 cm). Two patients had a positive Trendelenburg sign, and three had a slight limp at the time of the latest follow-up. No cases of nonunion or nerve palsy were encountered. Postoperative dislocations occurred in two hips. One hip showed progressive radiolucent lines around the proximal femoral sleeve within two years after the surgery, and this was followed by progressive stem subsidence. Only one femoral stem was revised. Cementless, modular total hip arthroplasty combined with subtrochanteric osteotomy for the treatment of patients with prior Crowe Group-IV developmental dysplasia of the hip resulted in satisfactory outcomes. Hips with poor bone quality and a developmentally short femoral neck present technical challenges with regard to achieving sufficient rotatory stability, following osteotomy, for osseointegration of the modular implants. Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

Total Hip Arthroplasty Using S-ROM Prosthesis for Dysplastic Hip

PurposeThe purpose of this study was to evaluate the clinical and radiological results of total hip arthroplasty using a proximal modular femoral stem in patients who had secondary coxarthrosis associated with a dysplastic hip.Materials and MethodsForty-two patients (45 hips) with secondary coxarthrosis were evaluated after undergoing primary total hip arthroplasty using an S-ROM proximal modular femoral stem. The average follow-up was 80 months (range: 60 to 96 months). Clinical and radiological assessments were performed based on the Harris hip score and the radiological changes around the prosthesis.ResultsThe average Harris hip score improved from 52.2 points to 88.5 points. All femoral stems showed stable fixation; there were 37 cases by bony ingrowth and 8 cases by stable fibrous ingrowth. Neither osteolysis nor progressive radiolucent lines around the femoral stem were found at the last follow-up. Forty-one hips (91.9%) revealed excellent or good clinical results at the most recent follow-up.ConclusionFor advanced secondary coxarthrosis, total hip arthroplasty with the use of the proximal modular femoral stem yielded good mid-term results with respect to the clinical and radiological criteria.

Reverse hybrid total hip arthroplasty in select patients

Abstract Purpose To report the result of cemented cups and cementless stems (reverse hybrid) in 17 total hip arthroplasties (THAs). Methods From January 2003 to January 2008, 17 hips (17 patients) received reverse hybrid THAs and were included in this study. The mean patient age was 70 years (range, 52–81 years). The reasons for a reverse hybrid THA were an acetabulum too small to accommodate a metal shell, a severely osteoporotic acetabulum with thin subchondral bone, in which press-fit and screw fixation of the metal shell was deemed unstable, irradiation arthritis, and sequelae of sepsis, while the proximal femoral canal is normally shaped for a press-fit stem. Demographic data, surgical techniques, reasons for surgery, Harris hip score, and complications were reported. Results The average Harris hip score was 84.4 (range, 48–100) points at an average follow-up of 40.1 months (range, 24–73 months). One patient had a Vancouver type 2B fracture and received reoperation with open reduction. The patient had a 3-cm subsidence of the stem and thigh pain at follow-up. Another patient had an asymptomatic 1.5-cm subsidence of the stem. No loosening, migration, or progressive radiolucent lines around the cup were noted in any patient. Conclusion Reverse hybrid THA was associated with good clinical and radiographic results of the cemented cups in patients with the four selection criteria. It is noteworthy that one periprosthetic femoral fracture and one asymptomatic stem subsidence occurred. The lower average hip score with reverse hybrid THA than with ordinary THA is attributable to major comorbidities in the patients.

Three- to six-year follow-up results after high-flexion total knee arthroplasty: can we allow passive deep knee bending?

We evaluated 3- to 6-year clinical and radiological follow-up results after NexGen® LPS-flex total knee arthroplasty (TKA). A retrospective evaluation was undertaken of 218 knees in 166 patients (22 males, 144 females) who were followed up for more than 3 years after TKA. Evaluations included preoperative and postoperative range of motion (ROM) measurement, Knee Society (KS) Score, tibiofemoral angle and assessment of postoperative complications. TKA resulted in a significant ROM increase from a mean flexion contracture of 9° (range 0°-20°) and further flexion of 117° (range 80°-155°) to a mean flexion contracture of 2° (range 0°-10°) and a further flexion of 131° (range 95°-155°). KS knee and function scores significantly improved from 52 and 38 before surgery to 87 and 82 after surgery, respectively. The tibiofemoral angle significantly improved from varus 5.7° to valgus 5.4°. Progressive radiolucent lines around the femoral component on radiographs were observed in 30 knees (13.8%, 27 patients), and more of those knees, could squat than non-radiolucent knees (76.7 vs. 20.2%; P<0.05). Seven knees (3.2%, 6 patients) were revised at a mean 49 months after the index operation. While NexGen® LPS-flex TKA satisfactorily improved ROM, it was associated with a relatively high incidence of early loosening of the femoral components. This might be associated with passive-maximal flexion activity, such as squatting or kneeling. The clinical relevance of this study is that squatting or kneeling, common activity in Asian, may not be allowed after NexGen® LPS-flex TKA.

Failure Patterns After Linked Semiconstrained Total Elbow Arthroplasty for Posttraumatic Arthritis

Total elbow arthroplasty for the treatment of posttraumatic arthritis is associated with a relatively high failure rate. An understanding of these failures can lead to improved implant design and surgical technique. Eighty-four consecutive patients underwent eighty-five semiconstrained total elbow arthroplasties for the treatment of posttraumatic arthritis. Sixty-nine elbows with a retained primary prosthesis were followed for an average of nine years. Clinical results were graded with use of the Mayo Elbow Performance Score. Radiographs were assessed for mechanical failure, and all complications were recorded. Sixteen primary arthroplasties (19%) failed. Causes of failure included isolated bushing wear (seven), infection (four), component fracture (three), and component loosening (two). The most common cause of early failure (failure after less than five years) was infection, whereas intermediate-term failure (failure after five to ten years) typically was due to bushing wear. Late failure (failure after more than ten years) was uncommon and involved component loosening or fracture. Seventy-five percent of the failures were in patients who were less than sixty years old at the time of surgery (p = 0.03). Progressive radiolucent lines were noted around four implants, three of which had clinically important loosening. Total elbow arthroplasty was associated with significant improvements in terms of pain, motion, and the Mayo Elbow Performance Scores (p < or = 0.002). Sixty-eight percent of the patients achieved a good or excellent clinical result, and 74% were subjectively satisfied. Kaplan-Meier analysis demonstrated a fifteen-year survival rate of 70% with revision or resection for any reason as the end point. Semiconstrained total elbow arthroplasty in patients with posttraumatic arthritis places high demands on the implant and is associated with a relatively high failure rate. Seventy-five percent of failures occur in patients less than sixty years of age, and infection continues to represent a frequent mode of early failure. Bushing wear and component loosening or fracture are seen more commonly in the intermediate and late term, whereas aseptic loosening remains relatively uncommon.

Examining the Ethical Implications of an Orthopaedic Joint Registry

R.P., a fifty-seven-year-old man, underwent a total hip replacement with a newly designed, cementless hip system. Within the first several months after surgery, he had persistent thigh pain. Radiographs made at one year indicated progressive radiolucent lines surrounding the femoral component. He required revision surgery for aseptic loosening of the femoral component. Several months following the revision, a single journal article indicating a similar problem at another institution with the same device was published. A year later, two additional articles appeared in the literature. One year later, the femoral device originally implanted in R.P. was removed from the market.

Acetabular revision with impacted morsellised cancellous bone grafting and a cemented acetabular component

We present an update of the clinical and radiological results of 62 consecutive acetabular revisions using impacted morsellised cancellous bone grafts and a cemented acetabular component in 58 patients, at a mean follow-up of 22.2 years (20 to 25). The Kaplan-Meier survivorship for the acetabular component with revision for any reason as the endpoint was 75% at 20 years (95% confidence interval (CI) 62 to 88) when 16 hips were at risk. Excluding two revisions for septic loosening at three and six years, the survivorship at 20 years was 79% (95% CI 67 to 93). With further exclusions of one revision of a well-fixed acetabular component after 12 years during a femoral revision and two after 17 years for wear of the acetabular component, the survivorship for aseptic loosening was 87% at 20 years (95% CI 76 to 97). At the final review 14 of the 16 surviving hips had radiographs available. There was one additional case of radiological loosening and four acetabular reconstructions showed progressive radiolucent lines in one or two zones. Acetabular revision using impacted large morsellised bone chips (0.5 cm to 1 cm in diameter) and a cemented acetabular component remains a reliable technique for reconstruction, even when assessed at more than 20 years after surgery.

Impacted Bone Allografts and a Cemented Stem after Failure of an Uncemented Stem: Preliminary Results

We reviewed the results of impaction bone grafting technique and a cemented stem in 27 consecutive patients with a failed uncemented femoral component. At an average follow-up of 55 months (25 to 94) none of the femoral components were removed or revised because of aseptic loosening or deep infection. In one hip a non progressive radiolucent line was observed in Gruen zone 5 with no clinical evidence of failure. The average postoperative Merle d'Aubigné and Postel Hip Score was 5.8 points for pain, 5.5 points for mobility and 5.4 points for gait. Revision of a failed uncemented stem with impaction grafting technique provided pain relief and improved function. The rate of success and restoration of bone stock were encouraging at mid-term follow-up.

Cementless total hip replacement: a prospective clinical study of the early functional and radiological outcomes of three different hip stems

Optimal fixation of cementless total hip stems is essential for long-term survival rates. The purpose of this prospective study was to evaluate the early clinical and radiological outcomes of two new total hip stems with metaphyseal (Symax®) and predominantly diaphyseal (Hipstar®) anchoring principles in comparison to the well-established straight Zweymueller (SL-Plus®) stem. Clinical and radiological evaluations of 74 patients were undertaken preoperatively as well as at 6 and 12 months postoperatively using the Harris Hip Score (HHS) and Western Ontario and McMaster Universities-Score. During follow-up no stem had to be revised. The mean preoperative HHS of the three study groups amounted to 54.6 ± 15.7 points. At the 12 months follow-up the mean HHS in the SL-Plus group (n = 22) was 88.3 ± 10.5 points, in the Hipstar group (n = 25) 83.3 ± 15.0 and the in Symax group (n = 27) 83.6 ± 15.1. Due to stress shielding the straight Hipstar stem revealed radiolucent lines in the proximal Gruen zones of about 60%, whereas the SL-Plus stem showed significantly more radiolucent lines (87%). However, subsequent long-term studies must be carried out in order to clarify if the progression of radiolucent lines may influence the clinical result and implant longevity.

Clinical and radiological outcomes after revision to the low-contact-stress mobile-bearing total knee arthroplasty

The aim of the present study was to investigate the short-medium-term clinical and radiological outcomes in revision total knee arthroplasty using a mobile-bearing implant. Forty patients (42 knees) who had revisions using the New Jersey low-contact-stress (LCS) mobile-bearing total knee arthroplasty between 1996 and 2000 were reviewed. The average age at revision was 71 years (range, 38-86 years) and the average follow up was 6 years (range, 5-9 years). Of the 34 patients reviewed clinically, six had excellent results, and 20 had good results, to give a total of 76% excellent or good results. There were five (15%) fair results and three (9%) poor results. Seven patients required revision of the components. There was one case of instability within the first year of revision, which required only exchange of the polyethylene bearing to achieve a satisfactory clinical outcome. Of the 31 knees reviewed radiologically, progressive radiolucent lines were seen at the bone-cement interface in five (16%) of the femoral components and in two (6%) of the tibial components. Unconstrained LCS mobile-bearing total knee arthroplasty can be used in revision surgery with satisfactory results after medium-term follow up (level of evidence: therapeutic level III).

Langzeitergebnisse nach zementiert und zementfrei verankerter S.T.A.R.-Prothese beim Rheumapatienten

We report the clinical and radiological results of 65 S.T.A.R. prosthesis that were performed be-tween 1993 and July 2000 in our two institutions. Cementless fixation was used in 38 prosthesis and cement fixation in 27. Rheumatoid arthritis was the main diagnosis, with females dominating. The average follow-up was 9.3 years for cemented S.T.A.R. prostheses and 11.3 years for cementless S.T.A.R. prostheses. The follow-up was based on the Kofoed ankle score, which consists of three tests, one subjective dealing with pain and two objective parts about ankle function and mobility. 23 patients (77.4%) with cementless fix-ation achieved good and excellent results. The Kofoed ankle score improved from preoperatively 44.7 to an average of 80.7 points at final examination. The cemented S.T.A.R. prosthesis gained an average score of 76,3 postoperatively, representing 16 (64%) implants with good and excellent result. The mobility score showed a moderate rise in range of motion for extension and flexion (+8.5°), while a decrease in subtalar joint movement has been noted. This is due to additional subtalar and talonavikular arthrodesis. For cemented S.T.A.R.-prosthesis we had to recognise progressive radiolucent lines of the tibial component in 11 (44%) patients and talar subsidence in eight (32%). We had three tibial exchange arthroplasties and six arthrodesis due to prosthesis loosening. The radiographic analysis showed radiolucent lines of the flat tibial component in seven cases (22.5%) of the cementless prosthesis. Five (16%) times we had to recognise talar subsidence. We had to perform six (19.3%) revisions because of meniscal breakage or insufficient meniscal height. An exchange of the talar component was necessary twice. Three prosthesis had to be revised with arthrodesis due to symp-tomatic loosening. In conclusion, cementless ankle arthroplasty using the cementless S.T.A.R.-prosthesis proved excellent clinical and radiological long-term results, especially for rheumatoid patients. The success of ankle arthroplasty depends on careful indication, cementless fixation of a second generation total ankle arthroplasty and appropriate rehabilitation. Cement fixation in total ankle arthroplasty should be abandoned.

Clinical observation of particulate cancellous bone impaction grafting in combination with total hip arthroplasty for acetabular reconstruction

To investigate the effect of particulate cancellous bone impaction grafting in combination with total hip arthroplasty (THA) for acetabular reconstruction in patients with posttraumatic arthritis and bone loss after acetabular fractures. Totally 15 consecutive cases with unilateral acetabular fracture were treated with bone impaction grafting in combination with THA in our department. There were 10 males and 5 females with mean age of 48.2 years (ranging from 36 to 73 years). Eight cases had the fracture at left hips, 7 at right hips. The average age at injury was 28 years (ranging from 18 to 68 years). The mean follow-up period was 4.3 years (ranging from 2 to 7 years). Compared with mean 42 points (ranging from 10 to 62) of the preoperative Harris score, the survival cases at the final follow-up had mean 84 points (ranging from 58 to 98). One patient had mild pain in the hip. No revision of the acetabular or femoral component was undertaken during the follow-up. Normal rotational centre of most hips was recovered except 2 cases in which it was 0.8 mm higher than that in opposite side. All of them had a stable radiographic appearance. Progressive radiolucent lines were observed in I, III zones in 2 cases. One patient had a nonprogressive radiolucent line in zone III. The cup prosthesis was obviously displaced (6 mm) in one patient, but had not been revised. Particulate cancellous bone impaction grafting in combination with THA as a biological solution is an attractive procedure for acetabular reconstruction in patients with posttraumatic arthritis and bone loss after acetabular fracture, which can not only restore acetabular bone stock but also repair normal hip anatomy and its function.

The early radiological follow-up of a medial rotational design of total knee arthroplasty

The objective of this study was to investigate the hypothesis that the increased constraint of a medial rotational knee promotes earlier loosening of the prosthesis. All patients with a Freeman-Samuelson 1000 knee arthroplasty (medial pivot design), (group 1), or a Freeman-Samuelson Modular knee arthroplasty, (group 2), with a minimum follow-up of 2 years (mean follow-up 4 years) were identified from our unit's arthroplasty database, and matched as closely as possible for age, length of follow-up and pre-operative diagnosis. Standardised anteroposterior and lateral radiographs were analysed for component migration and radiolucent lines as recommended by the Knee Society. There were 48 knees in each group. There were no failures in group 2. There was one failure requiring revision of the tibial component in group 1. There was no significant difference in overall radiolucent line scores between the two groups ( p = 0.66, at 5 years). Progressive radiolucent lines were detected in similar numbers of patients in both groups (FS1000 8/48, FSM 7/48, p = 0.84). Our early radiological survey suggests that the increased constraint of the medial pivot knee prosthesis does not result in an increased incidence of radiographic loosening.

Amphiphilic bonder improves adhesion at the acrylic bone cement–bone interface of cemented acetabular components in total hip arthroplasty: in vivo tests in an ovine model

Even following the introduction of the "third generation" cementing technique, an improvement of the fixation of the acetabular component similar to that of the femoral has not been shown in clinical studies. The goal of the present study was to achieve a better stability with the use of an amphiphilic bonder while preserving the mechanically important subchondral sclerosis. In a total of 20 sheep, a cemented total hip replacement was implanted. In the treatment group (n = 10), the implantation was carried out following surface conditioning of the acetabular bed with an amphiphilic bonder. All the sheep were followed for 9 months. To assess the biocompatibility, the osseous ingrowth at the cement-bone interface was depicted with the help of an in vivo fluorescent marking of the osteoblasts. Additionally, conventional radiographs were obtained over the course of treatment. Finally, the ovine pelvic regions were split following a standardized technique allowing for histological evaluation of the cement-bone interfaces. The acetabular components of the treatment group revealed a stable cement-bone compound. In the control group, the implants were easily dislodged from their beds. This finding was consistent with the radiological and histological results, which had revealed increased, progressive lytic radiolucent lines and the interposition of fibrous tissue at the cement-bone interface in the control group compared to the treatment group. The bonder was biocompatible. Following the application of the bonder, the cemented acetabular components revealed an improved stability without signs of inflammation or neoplasia in a viable acetabular osseous bed. With the help of this technique, the in vivo longevities of cemented acetabular components can be increased in the clinical setting without sacrificing the biomechanical relevant subchondral sclerosis.

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Since its development in the 1970s, total shoulder replacement has been favored by most surgeons for the management of primary osteoarthritis of the shoulder. While some studies have suggested that glenoid loosening is rare, long-term studies suggest that 50% of total shoulders will experience painful glenoid loosening if followed for greater than 10 years. The evidence of progressive radiolucent lines on the glenoid side in virtually all series is worrisome. Mid-term results of a prospective series of 47 shoulders undergoing hemiarthroplasty for primary osteoarthritis of the shoulder were presented in 1998. This study represents the continued long-term prospective study of this cohort. Follow-up averaged 8.7 years. Review both radiographic and clinical was done with careful assessment of the cause of failure. Non-concentric reduction was the most common cause of a fair or poor (9%), leading to asymmetric glenoid erosion. 8% of the failures were unclear, with normal radiographs at follow-up. At longer-term follow-up four additional patients developed pain; no further patients required revision surgery. A subset of four patients with hemiarthroplasty on one side and total shoulder were meticulously studied. At final follow-up the UCLA, ASES, VAS pain scores, and Simple Shoulder Test showed no significant differences in any subcategory for this unique subgroup of patients. Hemiarthroplasty is shown to provide satisfactory long-term results provided concentric reduction can be obtained in a high percentage of patients, consistent with Neer’s revision rate of zero for his own 20-year series of hemiarthroplasties. Long-term follow-up did not show a significant increase in revisions rates over mid-term results. While the failed hemiarthroplasty is often ascribed to the lack of a glenoid component, other factors such as soft tissue problems are equally likely. Careful soft tissue balancing with appropriate alteration of version of the component appears to allow good results permitting centering of the arthroplasty without placement of a glenoid component. Hemiarthroplasty appears to provide reasonably long-term results without the risk of late glenoid loosening, and may be preferable in the population where glenoid loosening is of concern. If noted, the author indicates something of value received. The codes are identified as follows: a, research or institutional support; b, miscellaneous funding; c, royalties; d, stock options; e, consultant or employee. *The Food and Drug Administration has not cleared the drug and/or medical device for the use described in this presentation (ie, the drug or medical device is being discussed for an “off-label” use). If noted, the author indicates something of value received. The codes are identified as follows: a, research or institutional support; b, miscellaneous funding; c, royalties; d, stock options; e, consultant or employee. *The Food and Drug Administration has not cleared the drug and/or medical device for the use described in this presentation (ie, the drug or medical device is being discussed for an “off-label” use). If noted, the author indicates something of value received. The codes are identified as follows: a, research or institutional support; b, miscellaneous funding; c, royalties; d, stock options; e, consultant or employee. *The Food and Drug Administration has not cleared the drug and/or medical device for the use described in this presentation (ie, the drug or medical device is being discussed for an “off-label” use).

A constrained acetabular component for recurrent dislocation

We treated 34 patients with recurrent dislocation of the hip with a constrained acetabular component. Roentgen stereophotogrammetric analysis was performed to assess migration of the prosthesis. The mean clinical follow-up was 3.0 years (2.2 to 4.8) and the radiological follow-up was 2.7 years (2.0 to 4.8). At the latest review six patients had died and none was lost to follow-up. There were four acetabular revisions, three for aseptic loosening and one for deep infection. Another acetabular component was radiologically loose with progressive radiolucent lines in all Gruen zones and was awaiting revision. The overall rate of aseptic loosening was 11.8% (4 of 34). Roentgen stereophotogrammetric analysis in the non-revised components confirmed migration of up to 1.06 mm of translation and 2.32 degrees of rotation at 24 months. There was one case of dislocation and dissociation of the component in the same patient. Of the 34 patients, 33 (97.1%) had no further episodes of dislocation. The constrained acetabular component reported in our study was effective in all but one patient with instability of the hip, but the rate of aseptic loosening was higher than has been reported previously and requires further investigation.