Minimal Osteolysis Research Articles

The correlation between acromial osteolysis and acromion types in the treatment of acromioclavicular joint dislocation with hook plate.

This study aimed to radiologically evaluate the effect of hook plates used in the treatment of acromioclavicular joint (ACJ) dislocations on the development of subacromial osteolysis (SAO) according to acromion types. A total of 43 patients with mean age of 38.5 (19-77) years who were diagnosed with AC dislocation and applied neutral clavicular hook plate between 2013 and 2020 were retrospectively evaluated. Acromion types were determined by measuring acromion slope angle on lateral shoulder radiography and 3-dimensional (D)-CT of the patients. Presence of SAO was classified according to the severity of erosion in the subacromial region (grade I: minimal osteolysis, grade II: subacromial erosion <2 mm, grade III: subacromial erosion >2 mm, grade IV: cut-through of the acromion) on postoperative 3D - CT and correlation with acromion types was analyzed. Incidence of SAO was significantly higher among type 1 acromion compared to type 2 and type 3 acromion (P = .003). While osteolysis was observed in 21 patients, no osteolysis was observed in 22 patients. Osteolysis occurred in all patients with type 1 acromion, 7 patients with type 2 acromion, and 5 patients with type 3 acromion. Since the hook tip in the sagittal plane passes posterior to the center of the acromion and the concavity of the subacromial surface is inadequate in the type 1 acromion, we believe that the increased pressure applied by the hook tip on the subacromial cartilage increases the risk of SAO. We predict that the use of hook plates with an angle of 15-20 degrees, similar to the patient's AC angle, rather than neutral hook plate, will reduce the risk of osteolysis in patients with type 1 acromion.

A novel hip joint prosthesis with uni-directional articulations for reduced wear

A novel polymer-on-metal hip joint prosthesis design that makes use of uni-directional articulations was developed and tested in this work. The new implant was tested using two polymer variants, virgin ultra-high molecular weight polyethylene (UHMWPE), and Vitamin E-infused highly crosslinked polyethylene (VEHXPE). The degrees of freedom of the ball-and-socket are reproduced by three cylindrical orthogonally-aligned articulations. This unconventional design leverages on the molecular orientation hardening mechanisms of the polyethylene and increased contact area to minimize wear. An experimental hip joint simulator was used to compare the gravimetric wear of the conventional ball-on-socket and the new implant. The new prosthesis including UHMWPE components produced a 78% reduction in wear, whereas the new prosthesis with VEHXPE components produced a 100% reduction in wear, as no measurable wear was detected. Machining marks on the acetabular cups of the new prosthesis were retained for both polyethylene variants, further demonstrating the low levels of wear exhibited by the new implants. Both polyethylene materials produced particles in the range of 0.1–1.0 μm, which are the most biologically active. Nonetheless, the extremely low wear rates are likely to induce minimal osteolysis effects. Furthermore, the novel design also offers an increase of more than 24% in the range of motion in flexion/extension when compared to a dual-mobility hip implant. A prototype of the prosthesis was implanted into a Thiel-embalmed human cadaver during a mock-surgery, which demonstrated high resistance to dislocation and the possibility of performing a figure of four position.

Percutaneous, Transtrapezial Fixation without Bone Graft Leads to Consolidation in Selected Cases of Delayed Union of the Scaphoid Waist.

Purpose We evaluated clinical and radiographic outcome of percutaneous transtrapezial fixation of the scaphoid delayed union or nonunion using a headless bone screw without bone grafting. Methods Sixteen patients with delayed union or nonunion of the scaphoid were included in this retrospective study between 2006 and 2011. All patients had a delayed presentation of scaphoid fracture, and none of them was treated conservatively elsewhere. Patients with bone graft, sclerotic bone debridement, or displacement of the fragment at the nonunion site were excluded. A percutaneous transtrapezial fixation technique was used in all cases. Patients were reviewed until clinical and radiographic union was observed. At the final follow-up, DASH (Disabilities of the Arm, Shoulder and Hand) and PRWHE (Patient-Rated Wrist and Hand Evaluation) outcome scores were completed. Results Radiographic union was obtained in 15 out of 16 patients (94%) at an average follow-up of 36 months (range: 12-98 months). No complications from the percutaneous technique were noted. The average DASH score was 6 (range: 0-39) and the average PRWHE score was 10 (range: 0-56). No statistical significant difference in range of motion and grip strength was found between the operated side and the contralateral side. Conclusion Percutaneous transtrapezial screw fixation for delayed or nonunion of selected scaphoid fractures without bone grafting is promising. At a mean of 4 months, 94% union was obtained with good functional results when there was no sclerosis, minimal osteolysis, and no displacement at the scaphoid nonunion site. Type of Study Therapeutic study. Level of Evidence IV.

Sea urchin spine arthritis in the foot

We present a case of sea urchin spine arthritis (SUSA) in a 33-year-old woman who sustained penetrating trauma to the interphalangeal (IP) joint of the hallux while snorkeling in Japan. Serial radiographs and MRI were obtained over a period from 7 weeks to 10 months following injury. At 7 weeks radiographs revealed periarticular osteopenia and subtle marginal erosion, similar to the appearance of tuberculous arthritis. Over the ensuing months, radiographs and MRI documented progressive marginal and periarticular erosions with synovitis, despite preservation of cartilage space and restoration of bone mineral density. Delayed radiographs and imaging features mimic gouty arthropathy. Only the history points to the proper diagnosis, which was confirmed by histopathology, demonstrating necrobiotic granuloma with central fibrinoid necrosis following synovectomy and arthrodesis. The majority of previous case reports affected the hand, with few cases in the feet. In all, radiographic illustrations were limited and demonstrated only minimal osteolysis and periosteal reaction. No other report included MRI or serial radiographs over a long period to illustrate the natural progression of the disease.

COMPUTED TOMOGRAPHIC FEATURES OF FELINE NASOPHARYNGEAL POLYPS

The computed tomographic (CT) findings of histopathologically confirmed nasopharyngeal polyps are described in 13 cats. Most polyps were mildly hypoattenuating to adjacent muscles and isoattenuating to soft-tissue (n= 13), homogeneous (n = 12) and with ill-defined borders (n = 10) on precontrast images. After contrast medium administration, the polyps were homogeneous (n = 11), with well-defined borders (n = 13), oval (n = 13), and had rim enhancement (n = 13). Nasopharyngeal polyps were pedunculated in 11 cats with a stalk-like structure connecting the polyp through the auditory tube to an affected tympanic bulla. All cats had at least one tympanic bulla severely affected, with CT images identifying: (1) complete (n = 12) or partial (n = 1) obliteration of either the dorsal or ventral compartments with soft-tissue attenuating material; (2) pathologic expansion (n = 13) with wall thickening (n = 10) that was asymmetric in nine cats; and (3) identification of a polyp-associated stalk-like structure (n = 11). Nine cats had unilateral tympanic bulla disease ipsilateral to the polyp, and four cats had bilateral tympanic bulla disease, most severe ipsilateral to the polyp with milder contralateral pathologic changes. Two cats had minimal osteolysis of the tympanic bulla. Enlargement of the medial retropharyngeal lymph node was seen commonly (n = 8), and in all cats it was ipsilateral to the most affected tympanic bulla. One cat had bilateral lymphadenopathy. CT is an excellent imaging tool for the supportive diagnosis of nasopharyngeal polyps in cats. CT findings of a well-defined mass with strong rim enhancement, mass-associated stalk-like structure, and asymmetric tympanic bulla wall thickening with pathologic expansion of the tympanic bullae are highly indicative of an inflammatory polyp.

Abstract 5236: Development of chronic disease model of metastatic estrogen receptor positive (ER+) breast cancer (BC)

Abstract Expression of estrogen and progesterone receptors (ER, PR) in metastatic BC (MBC) strongly predicts for estrogen-dependence and, hence, for response to estrogen withdrawal (EWD) and to pharmacological anti-estrogens (AE). However, the choice of agents and their sequence is empiric and lacks a solid scientific foundation, largely because we lack in vivo models that accurately replicate chronic human ER+ MBC. In order to generate bone(marrow) metastasis models, highly bone tropic MCF7 or T47D cells (HER2-) or BT474 (HER2+) ER+, PR+ BC cells were selected in vivo by repeated rounds of intratibia injection, harvest and reinjection in nude mice. Histologically, MCF-7- and T47D-derived tumors fill the marrow sinusoids, with minimal osteolysis. In contrast, ER+, HER2+ BT474 cells give rise to expansile osteolytic metastases associated with osteoclast activation, reminiscent of the phenotype seen in basal-like MBC models. In order to test the estrogen-dependence of bone metastases in vivo, bone tropic MCF7 cells were injected into the tibiae of oophorectomized mice. One group received estradiol (E2) supplementation, while the control group did not. Serial in vivo imaging confirmed the appearance of mixed osteolytic and -blastic bone lesions in the E2-treated group but not in the control group. In addition, we were able to detect regional metastases to the adjacent femur and fibula. At 12 weeks, E2 pellets were removed from the treatment group. E2 deprivation induced rapid resolution of lytic lesions and pathological fractures associated with dramatic callus formation. The experiment was terminated 18 weeks later. Histologically, the residual tibial tumors were epithelioid, and still expressed cytokeratin, E-cadherin, ER and PR. Primary cell lines were established from 5 of the 5 animals. Of these, 2 were still E2-dependent in vitro and ER+, PR+. Of the 3 remaining E2-independent lines, one was ER-, PR-, and one was ER+, PR-. To determine whether or not the MCF7 cells inoculated into the control mice had retained viability and tumorigenic potential even in the absence of exogenous estrogen, E2 pellets were introduced at 12 weeks after intra-tibia injection. Ten weeks later, histological analysis failed to detect any tumor growth. However, we were able to isolate a new tertiary MCF7 subclone from 1 of 5 of these mice. This cell line is E2-dependent in vitro and ER+, PR+. In conclusion, bone-tropic MCF7-derived BC clones retain E2-dependence in a bone marrow microenvironment in vivo. Skeletal metastases respond rapidly to EWD, followed by the emergence of E2-independent subclones. In addition, in the absence of E2, bone tropic MCF7 cells are able to remain dormant but viable in a bone marrow microenvironment in vivo for prolonged periods of time. Thus, this in vivo mouse model faithfully reproduces chronic ER+, PR+ MBC and will allow us, for the first time, to develop rational treatment strategies for this disease. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5236. doi:10.1158/1538-7445.AM2011-5236

Letter to the Editor: THA with the ABG I Prosthesis at 15 Years: Excellent Survival with Minimal Osteolysis

To the Editor: I read the paper by Baker et al. [1] with great interest. The authors reported high survival with minimal osteolysis using the ABG-1 prosthesis in total hip arthroplasties (THA). Their 15-year survival rates of the acetabular and femoral components were 86.9% and 98.6%, respectively, and they concluded that the ABG-1 prosthesis continues to show excellent long-term results. Unfortunately, I cannot confirm these positive findings for the ABG-1 prosthesis, especially regarding the cup. Poor survival of ABG-1 prostheses implanted from 1994 to 1995 was observed, with periprosthetic osteolysis and aseptic cup loosening being leading reasons for revision [7]. The overall 12-year cumulative survival was 0.55 (95% CI, 0.443–0.659), which is much poorer than the survival reported by Baker et al. This also disagrees with reports from other centers [2, 4, 5, 10]. The Swedish hip arthroplasty register’s annual 2007 report [13] found an increased risk of revision with ABG-1 cups (1.28 [95% CI, 1.06–1.54], Cox regression). Similarly, the 10-year survivorship was 80.5% ± 4.5%. In contrast, several studies [3, 9, 12] report data consistent with that provided by Baker et al.; therefore, I think the issue deserves careful comment. Baker et al. reported the experience of one center and a single-surgeon patient group, which could point toward patient selection and surgical factors that could favor these patients over those receiving surgery performed by several surgeons at several different centers. However, the findings of Herrera et al., in a multicenter study of the ABG-1 prosthesis [9], are consistent with those of Baker et al., suggesting that this variable may not play an important role. Baker et al. did not report on variables that could influence implant survivorship such as primary diagnosis or cup size. The latter is closely associated with a risk of premature failure, especially in cementless THA, as it determines the thickness of the polyethylene (PE) liner. In earlier studies [6, 7], a thin PE liner increased the risk of premature failure, and patients with a cup < 50 mm (ie, with 5.9 mm maximal PE thickness) had an odds ratio and relative risk for revision of 4.278 and 2.135, respectively. Given these findings one wonders whether the patients in the study by Baker et al. could have received larger cups and thus achieved better survivorship because of this. Presuming selected patients, their conclusions may not be generalizable to a broader ABG-1-patient group and the readers should take selection into consideration. Baker et al. stated they observed no “high volumes of osteolysis” in their patients, regardless of revision. The reason might lie in a possible role of resistance to osteolysis development in their patients compared with those of Gallo et al. [8] and of others [11, 14]. Readers and authors of any study of the ABG-1 prosthesis should consider the contradictory data regarding survivorship, increased risk of revision, PE wear rate, and osteolysis until the reasons for these discrepancies can be explained. The article by Baker et al. should be read with caution and patients with ABG-1 prostheses should be closely monitored.

Reply to Letter to Editor: THA with the ABG I Prosthesis at 15 Years: Excellent Survival with Minimal Osteolysis

We agree with the comments made by Dr. Gallo. The literature relating to this prosthesis is contradictory, with significant variation in the rates of implant survival, periacetabular osteolysis, and polyethylene wear. Numerous reports mirror Dr. Gallo’s experience of poor outcomes with this implant. Unfortunately we cannot offer additional insight regarding reasons why our results are better than those previously published. There is increasing evidence in relation to hard bearing surfaces that surgical technique and correct cup placement are more important than previously thought [1, 3]. It seems likely that these factors plus cup diameter/polyethylene thickness and polyethylene quality also will influence outcomes in other prostheses using conventional bearings. Recently Gallo et al. [2] suggested the position of the cup relative to Kohler’s line, increasing abduction angle of the cup, traumatic and inflammatory arthritis as a primary diagnosis, and patient weight all influence the rate of wear of the ABG I cup. Unlike that study, we did not see any relationship between cup abduction angle and polyethylene wear and unfortunately were unable to record these other determinants for our patient population. We also were unable to determine either the polyethylene thicknesses or the self lives and manufacturing batches of the polyethylene used in our series that may have been a marker of polyethylene quality. There is wide variation in reported details for surgical technique, surgeon numbers, bearing materials, and cup position for the ABG I. Missing information and the heterogeneity for the reports make it difficult to draw any direct comparison between series. What remains clear, however, is that the patients in whom an ABG I prosthesis has been implanted should continue to be closely monitored.

THA with the ABG I Prosthesis at 15 Years: Excellent Survival with Minimal Osteolysis

Following recent reports of poor results with the hydroxyapatite-coated ABG I prosthesis, we report the survival of a series of 63 patients (69 hips) at a mean of 15 years (range, 13-17 years). In total, eight patients had revision procedures. The reason for revision was acetabular loosening in all cases. In only one case was there associated clinical and radiographic loosening of the femoral stem. The 15-year survival of the acetabular component was 86.9% (95% confidence interval, 71.7%-96.0%) and the 15-year survival of the femoral component was 98.6% (95% confidence interval, 88.8%-100.0%). Periacetabular osteolysis was seen in 10 of 59 (17%) surviving hips. In these hips the components remained well fixed owing to the remaining bone-component contact. There was no difference in the Oxford hip score between patients with well-fixed hips and evidence of osteolysis and patients with hips without evidence of osteolysis. Multivariate analysis failed to reveal any factors associated with the presence of osteolysis (gender, age at primary surgery, Oxford hip score, cup abduction, and acetabular polyethylene wear rates). The ABG I prosthesis continues to show excellent long-term results. Ongoing radiographic review is recommended to detect progressive osteolysis that otherwise remains clinically silent until failure. Level IV, Case series. See Guidelines for Authors for a complete description of levels of evidence.

Third-Generation Alumina-on-Alumina Ceramic Bearings in Cementless Total Hip Arthroplasty

Wear debris has been implicated in the pathogenesis of osteolysis. Alumina-on-alumina ceramic bearings have a low wear rate, which may reduce the prevalence of osteolysis. The purpose of this study was to determine the rates of wear and osteolysis associated with modern cementless hip arthroplasty with alumina-on-alumina bearings at five years. We analyzed a series of 301 third-generation alumina-on-alumina cementless primary total hip replacements in 283 patients. The average age of the patients at the time of the arthroplasty was fifty-eight years. All procedures were performed with use of the same surgical technique and the same implant at a single center. At a minimum of five years postoperatively, ten patients had died and twenty-two patients were lost to follow-up. We assessed patients clinically and radiographically, and all retrieved bearings were analyzed for wear. At the time of the latest follow-up, the mean Harris hip score was 95 points. All surviving implants had radiographic evidence of stable bone ingrowth. There were nine revisions of one or both components. Four stems were revised following periprosthetic fracture, one stem was revised because of aseptic loosening at two months, and one stem was revised to facilitate a femoral shortening osteotomy. Two cups were revised because of psoas tendinitis, and both components of one arthroplasty were revised because of impingement and osteolysis. The rate of survival of both components, with revision because of aseptic loosening or osteolysis as the end point, was 99% at seven years. The retrieved femoral heads showed an early median wear rate of 0.2 mm(3) per year. Cementless primary total hip prostheses with a third-generation alumina-on-alumina bearing showed very low wear and were associated with minimal osteolysis at the time of follow-up, at a minimum of five years.

Good Stability and Minimal Osteolysis with a Biconical Threaded Cup at 10 Years

In the literature there is no consensus on the value of threaded cementless cups. We primarily asked whether the newly constructed threaded double-cone cup without additional screw fixation would provide high survival at intermediate followup. We retrospectively reviewed 365 patients (376 hips) who underwent primary total hip arthroplasty using this cup made of pure titanium with ceramic-on-polyethylene articulating surfaces. At a minimum followup of 10.0 years (mean, 10.3 years; range, 10.0-13.1 years), 232 cups (61.7%) were available for analysis. We performed two revisions for early infection and cup breakage. No polyethylene liner was exchanged because of wear or instability. Three of the cup shells were radiographically loose at followup; one had periacetabular osteolysis. The mean liner wear rate was 0.13 mm per year. The Kaplan-Meier 10-year survivorship with revision of the cup shell for any reason was 99.3% (95% confidence interval, 96.9-99.8%) and with revision and radiographic loosening of the cup shell 98.6% (95% confidence interval, 96.0-99.5%). These intermediate results compare favorably with survivorship and periacetabular bone reaction data observed with the best cementless acetabular implant designs.

Sterile Pretibial Abscess After Anterior Cruciate Reconstruction From Bioabsorbable Interference Screws: A Report of 2 Cases

We report 2 cases of extra-articular pretibial sterile abscesses with minimal osteolysis after anterior cruciate ligament reconstruction with poly-L-lactic acid bioabsorbable interference screw fixation. No joint involvement was evident in either case. Both patients underwent surgical exploration for incision, drainage, and excision with debridement of the biodegradable screw debris from the tibial bone tunnel. The cystic area in case 1 contained 8 mL of chalky white fluid with fragments of particulate matter. Microscopic evaluation revealed birefringent foreign material in a benign histiocyte-lined cyst. We encountered 20 mL of chalky white material during surgical debridement in case 2. Intraoperative cultures and Gram’s stain were negative. Both patients had an uneventful recovery after surgical debridement and were able to return to their athletic activities. To our knowledge, this is the first case report of a local reaction to poly-L-lactic acid bioabsorbable interference screws after anterior cruciate ligament reconstruction.

Metal on Metal Bearings in Hip Arthroplasty

Periprosthetic osteolysis caused by wear debris released from the bearing surface of polyethylene components is the major problem in contemporary hip arthroplasty. Several types of metal on metal prostheses were developed in the 1960s, but by the mid 1970s they were completely displaced by polyethylene bearings. There have been several generations of all metal components with significant variation in design, tolerances, and bearing surface quality. A number of these hips have survived for more than 25 years because of low wear rates and minimal osteolysis. Identification of the characteristics that contributed to long term function is important. The historical development and clinical results of metal on metal hip arthroplasties are presented. Factors that led to the abandonment of the metal on metal bearings are related to: (1) the early success of the Charnley prosthesis; (2) the frictional torque issue; (3) carcinogenesis concerns; (4) metal sensitivity concerns; (5) high infection rates; and (6) increased strain rates in periprosthetic bone and fatigue fractures of the acetabular floor. The accumulated experience to date enables one to evaluate all the factors with a different perspective and makes the use of newer metal on metal bearings a viable option in younger patients.