Increased lesion depth, higher body mass index and older age are risk factors for osteoarthritis during long-term follow-up in patients with osteochondritis dissecans of the knee

INTRODUCTION

To report on the long-term prognosis of osteochondritis dissecans (OCD) patients regarding radiological and patient-reported outcomes and to analyze possible risk factors.

MATERIALS AND METHODS

All patients diagnosed with knee OCD between 2004 and 2014 with radiographic Kellgren-Lawrence (K-L) grades 0-2 at the time of diagnoses, ability to understand the language of the interview, and willingness to participate in the study were retrospectively reviewed. Current knee radiographs and the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire were prospectively collected between May 2020 and March 2021. The extent of osteoarthritis (OA) and KOOS questionnaire results were evaluated.

RESULTS

90 patients (103 knees) with a mean age of 21 years (range 6-60) were included. The mean follow-up time was 12 years (range 7-20). 24 knees (23%) were treated conservatively, and 79 knees (77%) operatively. At the time of diagnoses, 90% of the patients had K-L grades of 0-1; during the follow-up period, 45% of the patients showed radiological progression of OA. Patient body mass index (BMI) (p = 0.004; 95% CI 0.25-0.29), age (p = 0.003; 95% CI 0.18-0.30), operative treatment (p = 0.0075; 95% CI 0.41-0.65) and lesion depth (p = 0.0007) were statistically significantly connected to K-L grade change. Patients with no progression in joint space narrowing had statistically significantly better overall KOOS scores (p = 0.03; 95% CI 0.77-0.88) than patients whose K-L grades worsened.

CONCLUSIONS

During the long-term follow-up of 12 years, patients with knee OCD had good clinical results. Lac of radiological progression of cartilage degeneration was noted in 55% of the patients, regardless of treatment method. Lesion depth, higher BMI and older age were associated with the progression of OA. The progression of OA was related to a worsening of functional scores.

LEVEL OF EVIDENCE

IV.

Arthroscopic partial meniscectomy for a degenerative meniscus tear: a 5 year follow-up of the placebo-surgery controlled FIDELITY (Finnish Degenerative Meniscus Lesion Study) trial

Objectives

To assess the long-term effects of arthroscopic partial meniscectomy (APM) on the development of radiographic knee osteoarthritis, and on knee symptoms and function, at 5 years follow-up.

Design

Multicentre, randomised, participant- and outcome assessor-blinded, placebo-surgery controlled trial.

Setting

Orthopaedic departments in five public hospitals in Finland.

Participants

146 adults, mean age 52 years (range 35–65 years), with knee symptoms consistent with degenerative medial meniscus tear verified by MRI scan and arthroscopically, and no clinical signs of knee osteoarthritis were randomised.

Interventions

APM or placebo surgery (diagnostic knee arthroscopy).

Main outcome measures

We used two indices of radiographic knee osteoarthritis (increase in Kellgren and Lawrence grade ≥1, and increase in Osteoarthritis Research Society International (OARSI) atlas radiographic joint space narrowing and osteophyte sum score, respectively), and three validated patient-relevant measures of knee symptoms and function (Western Ontario Meniscal Evaluation Tool (WOMET), Lysholm, and knee pain after exercise using a numerical rating scale).

Results

There was a consistent, slightly greater risk for progression of radiographic knee osteoarthritis in the APM group as compared with the placebo surgery group (adjusted absolute risk difference in increase in Kellgren-Lawrence grade ≥1 of 13%, 95% CI −2% to 28%; adjusted absolute mean difference in OARSI sum score 0.7, 95% CI 0.1 to 1.3). There were no relevant between-group differences in the three patient-reported outcomes: adjusted absolute mean differences (APM vs placebo surgery), −1.7 (95% CI −7.7 to 4.3) in WOMET, −2.1 (95% CI −6.8 to 2.6) in Lysholm knee score, and −0.04 (95% CI −0.81 to 0.72) in knee pain after exercise, respectively. The corresponding adjusted absolute risk difference in the presence of mechanical symptoms was 18% (95% CI 5% to 31%); there were more symptoms reported in the APM group. All other secondary outcomes comparisons were similar.

Conclusions

APM was associated with a slightly increased risk of developing radiographic knee osteoarthritis and no concomitant benefit in patient-relevant outcomes, at 5 years after surgery.

Trial registration

ClinicalTrials.gov (NCT01052233 and NCT00549172).

Favourable long-term functional and radiographical outcome after osteoautograft transplantation surgery of the knee: a minimum 10-year follow-up

PURPOSE

The aim of this study was to assess the progression of radiological cartilage changes and to document the functional, long-term results during a follow-up of 10 years after osteoautograft transplantation (OAT) knee surgery.

METHODS

The study was a retrospective analysis of all patients who underwent OAT at Turku University Hospital from 1999 to 2007. Pre- and postoperative cartilage changes were estimated based on standardised radiographs. The extent of osteoarthritis (OA) was graded according to the Kellgren-Lawrence scale. Clinical outcomes were evaluated with the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire.

RESULTS

A total of 60 patients (64 knees) with a median age of 30 years (range 14-62) were included. The median follow-up was 140 months (range 47-205). Of the 64 knees examined, 14 (22%) had a traumatic chondral lesion and 50 (78%) had osteochondritis dissecans (OCD). Preoperatively, 71% of the patients had Kellgren-Lawrence grades of 0-1; during the follow-up period, 50% of the patients showed radiographical progression of OA. OA progressed most significantly in patients with normal preoperative Kellgren-Lawrence grades (p = 0.0003). Patients with no progression in joint space narrowing had statistically significantly better overall KOOS (p = 0.02) than patients whose Kellgren-Lawrence grades worsened. Patients with defect sizes > 3.0 cm² scored statistically significantly better in all subscales than patients with smaller defect sizes (p = 0.02). Patients with OCD had statistically significantly better KOOS than patients with chondral defects (p = 0.008).

CONCLUSIONS

OAT surgery for treating patients with cartilage defects of the knee had good clinical results after a mean follow-up of 11 years. Radiological analyses revealed a progression of cartilage degeneration in 50% of the operated knees. Patients with no progression of the degenerative changes scored statistically significantly better on the KOOS self-assessment test. These results indicate that OAT surgery appears to be a reasonable therapeutic option to restore knee function in patients with cartilage lesions.

LEVEL OF EVIDENCE

IV.

Arthroscopic partial meniscectomy versus placebo surgery for a degenerative meniscus tear: a 2-year follow-up of the randomised controlled trial

OBJECTIVE

To assess if arthroscopic partial meniscectomy (APM) is superior to placebo surgery in the treatment of patients with degenerative tear of the medial meniscus.

METHODS

In this multicentre, randomised, participant-blinded and outcome assessor-blinded, placebo-surgery controlled trial, 146 adults, aged 35-65 years, with knee symptoms consistent with degenerative medial meniscus tear and no knee osteoarthritis were randomised to APM or placebo surgery. The primary outcome was the between-group difference in the change from baseline in the Western Ontario Meniscal Evaluation Tool (WOMET) and Lysholm knee scores and knee pain after exercise at 24 months after surgery. Secondary outcomes included the frequency of unblinding of the treatment-group allocation, participants' satisfaction, impression of change, return to normal activities, the incidence of serious adverse events and the presence of meniscal symptoms in clinical examination. Two subgroup analyses, assessing the outcome on those with mechanical symptoms and those with unstable meniscus tears, were also carried out.

RESULTS

In the intention-to-treat analysis, there were no significant between-group differences in the mean changes from baseline to 24 months in WOMET score: 27.3 in the APM group as compared with 31.6 in the placebo-surgery group (between-group difference, -4.3; 95% CI, -11.3 to 2.6); Lysholm knee score: 23.1 and 26.3, respectively (-3.2; -8.9 to 2.4) or knee pain after exercise, 3.5 and 3.9, respectively (-0.4; -1.3 to 0.5). There were no statistically significant differences between the two groups in any of the secondary outcomes or within the analysed subgroups.

CONCLUSIONS

In this 2-year follow-up of patients without knee osteoarthritis but with symptoms of a degenerative medial meniscus tear, the outcomes after APM were no better than those after placebo surgery. No evidence could be found to support the prevailing ideas that patients with presence of mechanical symptoms or certain meniscus tear characteristics or those who have failed initial conservative treatment are more likely to benefit from APM.

Bioabsorbable Versus Metal Screw in the Fixation of Tibial Tubercle Transfer: A Cadaveric Biomechanical Study

Background:

In tibial tubercle transfer (TTT) procedures, the osteotomized and transferred tibial tubercle is usually fixed into the host bone using metal screws.

Purpose:

To compare the strength of fixation provided by a single bioabsorbable screw versus a metal screw for TTT.

Study Design:

Controlled laboratory study.

Methods:

Twenty-two pairs of human cadaveric tibiae were used to compare the fixation strength of a single 4.5-mm bicortical bioabsorbable or metal screw for TTT. In our 2-phase biomechanical testing protocol, the specimens were first subjected to a cyclic-loading test (1500 loading cycles between 50 and 300 N at 0.5 Hz frequency), after which they were loaded to failure (single-cycle load-to-failure test). To control for possible differences in bone quality, volumetric bone mineral density was determined using peripheral quantitative computed tomography.

Results:

No significant displacement differences were observed between the 2 groups for the cyclic-loading test. In the subsequent single-cycle load-to-failure test, the mean yield load was 566 ± 234 N in the bioabsorbable screw group and 984 ± 630 N in the metal screw group (P = .002). The failure mode of bioabsorbable screws was breakage and/or bending, and that of metal screws was bending and/or pull-out. Bone density was similar in the 2 groups.

Conclusion:

A metal screw seems to provide greater fixation strength than a biodegradable screw in the TTT of a human cadaveric knee. However, considering the maximum quadriceps pull in vivo, the strength of fixation provided by a biodegradable screw seems clinically sufficient.

Clinical Relevance:

Bioabsorbable screws, particularly if used in duplicate, could provide a viable option for metal screws in TTT fixation.

Clinical Profile, Treatment Details and Survival of Trauma Patients Treated at Intensive Care Unit in a Level II Trauma Center

OBJECTIVE

This retrospective study evaluated all trauma patients who were admitted to intensive care unit in Turku University Central Hospital, Finland in 2000-2004.

METHODS

We reviewed details of demographic factors, injury mechanism, treatment details, and the overall recovery of patients after the hospital episode.

RESULTS

A total of 427 trauma patients were identified, 66% of these were severely injured (ISS > 15). 79% of patients were men. The median age of 44 years. The most frequent injury type was road traffic accidents, leisure-time accidents and injury mechanism a high-energy blunt trauma. Head injuries were the most frequently diagnosed severe injury and 59% of the patients were multiple traumatized.

CONCLUSIONS

Current results suggest that the overall survival of these patients is satisfactory, although, the head and cervical spine injuries are still often related to compromised prognosis. Despite the improvements in morbidity and mortality of these patients during last decades, still almost every tenth of trauma patient treated in the ICU dies to the complications of the injury.

Tendon Graft Healing in Multiligament Reconstructed Knee Detected by FDG-PET/CT: A Pilot Study

Background and Aims:

The detection of graft viability is challenging in the multiligament reconstructed knee. Magnetic resonance imaging gives structural information but lacks the capability to assess biological activity of the grafts. 18F-labeled fluorodeoxyglucose positron emission tomography combined with computer tomography is shown to be a sensitive method for imaging tissue metabolism and viability. The aim of the present study was to evaluate the feasibility of fluorodeoxyglucose positron emission tomography combined with computer tomography imaging in the detection of the replacement graft metabolism in multiligament reconstructed knees.

Materials and Methods:

Seven patients (17–44 years) with multiligament reconstructed knee underwent fluorodeoxyglucose positron emission tomography combined with computer tomography to evaluate the biological activity of replacement grafts. The degree of fluorodeoxyglucose uptake reported as standard uptake values from the region of interest was analyzed 3–24 months postoperatively.

Results:

In all patients, the fluorodeoxyglucose positron emission tomography combined with computer tomography showed increased fluorodeoxyglucose uptake in all replacement grafts at different follow-up time points. Furthermore, fluorodeoxyglucose was higher at femoral condyles of operated knees compared to contralateral reference values.

Conclusion:

This pilot study shows a significant increase in tendon graft metabolism during two first years of postoperative healing. The fluorodeoxyglucose positron emission tomography combined with computer tomography imaging seems to be adequate method of assessment of graft metabolism and viability during postoperative healing. The clinical value of fluorodeoxyglucose positron emission tomography combined with computer tomography imaging, however, warrants further evaluation with longitudinal studies with a larger patient population.

Adverse reaction to metal debris after Birmingham hip resurfacing arthroplasty

BACKGROUND AND PURPOSE

Concern has emerged about local soft-tissue reactions after hip resurfacing arthroplasty (HRA). The Birmingham Hip Resurfacing (BHR) was the most commonly used HRA device at our institution. We assessed the prevalence and risk factors for adverse reaction to metal debris (ARMD) with this device.

PATIENTS AND METHODS

From 2003 to 2011, BHR was the most commonly used HRA device at our institution, with 249 implantations. We included 32 patients (24 of them men) who were operated with a BHR HRA during the period April 2004 to March 2007 (42 hips; 31 in men). The mean age of the patients was 59 (26-77) years. These patients underwent magnetic resonance imaging (MRI), serum metal ion measurements, the Oxford hip score questionnaire, and physical examination. The prevalence of ARMD was recorded, and risk factors for ARMD were assessed using logistic regression models. The mean follow-up time was 6.7 (2.4-8.8) years.

RESULTS

6 patients had a definite ARMD (involving 9 of the 42 hips). 8 other patients (8 hips) had a probable ARMD. Thus, there was definite or probable ARMD in 17 of the 42 hips. 4 of 42 hips were revised for ARMD. Gender, bilateral metal-on-metal hip replacement and head size were not factors associated with ARMD.

INTERPRETATION

We found that HRA with the Birmingham Hip Resurfacing may be more dangerous than previously believed. We advise systematic follow-up of these patients using metal ion levels, MRI/ultrasound, and patient-reported outcome measures.

[Treatment of posterior cruciate ligament injury in skeletally immature patients]

Posterior cruciate ligament tear is a rare injury in the pediatric and adolescent population. Primary diagnosis of posterior cruciate ligament injury is based on careful attention to specific physical examination, but MRI is the mainstay for assessing the extent of ligamentous and possible associated injuries. In general, most of the posterior cruciate ligament tears in children and adolescents can be treated non-operatively with good functional outcome. Surgical treatment for these injuries should however be cautiously considered also for skeletally immature patients with a complete, intrasubstance ligament tear or dislocated avulsion fracture.

Arthroscopic partial meniscectomy versus sham surgery for a degenerative meniscal tear

BACKGROUND

Arthroscopic partial meniscectomy is one of the most common orthopedic procedures, yet rigorous evidence of its efficacy is lacking.

METHODS

We conducted a multicenter, randomized, double-blind, sham-controlled trial in 146 patients 35 to 65 years of age who had knee symptoms consistent with a degenerative medial meniscus tear and no knee osteoarthritis. Patients were randomly assigned to arthroscopic partial meniscectomy or sham surgery. The primary outcomes were changes in the Lysholm and Western Ontario Meniscal Evaluation Tool (WOMET) scores (each ranging from 0 to 100, with lower scores indicating more severe symptoms) and in knee pain after exercise (rated on a scale from 0 to 10, with 0 denoting no pain) at 12 months after the procedure.

RESULTS

In the intention-to-treat analysis, there were no significant between-group differences in the change from baseline to 12 months in any primary outcome. The mean changes (improvements) in the primary outcome measures were as follows: Lysholm score, 21.7 points in the partial-meniscectomy group as compared with 23.3 points in the sham-surgery group (between-group difference, -1.6 points; 95% confidence interval [CI], -7.2 to 4.0); WOMET score, 24.6 and 27.1 points, respectively (between-group difference, -2.5 points; 95% CI, -9.2 to 4.1); and score for knee pain after exercise, 3.1 and 3.3 points, respectively (between-group difference, -0.1; 95% CI, -0.9 to 0.7). There were no significant differences between groups in the number of patients who required subsequent knee surgery (two in the partial-meniscectomy group and five in the sham-surgery group) or serious adverse events (one and zero, respectively).

CONCLUSIONS

In this trial involving patients without knee osteoarthritis but with symptoms of a degenerative medial meniscus tear, the outcomes after arthroscopic partial meniscectomy were no better than those after a sham surgical procedure. (Funded by the Sigrid Juselius Foundation and others; ClinicalTrials.gov number, NCT00549172.).

Hip resurfacing arthroplasty versus large-diameter head metal-on-metal total hip arthroplasty: comparison of three Designs from the Finnish Arthroplasty Register

Background and Aims:

Large headed metal-on-metal total hip arthroplasty may produce more metal ions than hip resurfacing arthroplasty. Increased metal-ion levels may be associated with higher revision rates due to adverse reaction to metal debris. The purpose of our study was to compare the survivorship of three hip resurfacing arthroplasty designs with their analogous cementless large-diameter head metal-on-metal total hip arthroplasties.

Material and Methods:

Based on data obtained from the Finnish Arthroplasty Register, the revision risks of three metal-on-metal hip resurfacing arthroplasty/total hip arthroplasty design couples performed during 2001–2011 were analyzed using the Cox regression model.

Results:

In the Cox regression analysis for compared design pairs adjusted for age, gender, operated side, head size, diagnosis, and implant, there was no statistically significant difference in revision risk between ReCap hip resurfacing arthroplasty and Bimetric/ReCap total hip arthroplasty (risk ratio = 1.43, confidence interval = 0.95–2.14, p = 0.09) or between Birmingham hip resurfacing arthroplasty and Synergy/Birmingham hip resurfacing total hip arthroplasty (risk ratio = 1.35, confidence interval = 0.75–2.43, p = 0.31). However, the revision risk of Corail and Summit/articular surface replacement total hip arthroplasty (ASR HRA) was significantly increased compared to ASR HRA. (risk ratio = 0.73, confidence interval = 0.54–0.98, p = 0.04).

Conclusion:

We conclude that the short-term revision risk of large headed metal-on-metal total hip arthroplasties was not increased compared to analogous hip resurfacing arthroplasties in two out of three devices studied at a nationwide level. There may be implant-related factors having an effect on the success of single manufacturer devices. However, more information on the incidence of adverse soft-tissue reactions in these patient cohorts is needed.

Operatively treated traumatic versus non-traumatic rotator cuff ruptures: a registry study

BACKGROUND

Operative treatment of traumatic rotator cuff ruptures, i.e. ruptures with a predisposing traumatic event, is reported to yield superior results compared to operative treatment of non-traumatic, degenerative ruptures.

AIM

The purpose of this study was to evaluate the difference of outcome, peroperative findings, and demographics after operative treatment of traumatic versus non-traumatic rotator cuff rupture.

METHODS

A total of 306 consecutive shoulders with an operated rotator cuff rupture (124 traumatic and 182 non-traumatic) were followed up. Constant and Murley score, size of the rupture, and age of the patients were used as an outcome measure.

RESULTS

A total of 112 traumatic and 167 non-traumatic rotator cuff rupture shoulders were available for 1-year follow-up (91%). Mean Constant and Murley score was preoperatively lower in the traumatic group (46 versus 52, P = 0.01). At 3 months postoperatively, Constant and Murley scores were 61 and 60 (P = 0.72) and at 1 year 73 and 77 (P = 0.03), respectively. Altogether 91% of the patients in the traumatic and 93% in the non-traumatic group were satisfied with the final outcome (P = 0.45). In 94% of traumatic and 95% of a non-traumatic cases the rupture involved the supraspinatus tendon. In the traumatic group the rupture was larger and involved more frequently the whole supraspinatus insertion area (41% versus 17%, P < 0.0001). Mean age of patients was 58 and 57 years, respectively.

CONCLUSION

Operative treatment of both traumatic and non-traumatic rotator cuff ruptures gives essentially good results. In our cohort, patients' recollection of predisposing trauma reflects the size of the rotator cuff rupture, but does not reflect the age of the patients.

Bioceramic inlays do not improve mechanical incorporation of grit-blasted titanium stems in the proximal sheep femur

The aim of the present study was to determine, if bioactive glass (BG) surface inlays improve osseointegration of titanium implants in the proximal femur of adult sheep. In simulation of uncemented primary stems (nine animals), only the proximal part of the implants was grit-blasted and three surface slots of the grit-blasted region were filled with sintered BG microspheres. Primary stems were implanted using press-fit technique. In revision stem simulation (eight animals), grit-blasting was extended over the whole implant and seven perforating holes of the stem were filled by sintered BG granules. Revision stems were implanted with a mixture of autogenous bone graft and BG granules. Comparison with solid partially or fully grit-blasted control stems implanted in the contralateral femurs was performed in the primary and revision stem experiments at 12 and 25 weeks, respectively. Implant incorporation was evaluated by torsional failure testing and histomorphometry. Only one-third of the primary stems anchored mechanically to bone. The revision stems incorporated better and the BG inlays of the revision stems showed ingrowth of new bone. However, there were no significant differences in the torsional failure loads between the stems with BG inlays and the control stems. In conclusion, surface BG inlays gave no measurable advantage in mechanical incorporation of grit-blasted titanium implants. Overall, the proximal sheep femur, characterized by minimal amount of cancellous bone and the presence of adipocytic bone marrow, seemed to present compromised bone healing conditions.

Bioactive glass granules as extender of autogenous bone grafting in cementless intercalary implant of the canine femur

BACKGROUND AND AIMS

Ceramic bone graft substitutes have a potential to be used as replacement of allogeneic bone grafting and, under optimal distribution of particle size, they may even provide mechanical support. The current study examined the efficacy of bioactive glass granules as an extender of autogenous bone grafting in a segmental bone replacement model of the canine femur.

MATERIAL AND METHOD

A 16 mm long segment of the femur shaft was bilaterally replaced with an intercalary titanium implant in eight animals. The implant had cementless grooved proximal and distal stems. In one leg, the peri-implant space was packed with composite graft consisting of a mixture of bioactive glass granules and autogenous bone graft in proportion of 50:50. In the opposite leg, the peri-implant space was treated with autogenous bone graft alone. After surgery, unlimited functional loading was allowed. The outcome was evaluated at three months.

RESULTS

Eight out of sixteen autografted implants and seven out of sixteen composite-grafted implants were radiographically incorporated and clinically stable at three months. In the paired comparison, the proximal components of composite-grafted implants showed lower maximum load under torsional testing (p = 0.068), less new bone in the longitudinal grooves of the stems (p = 0.036) and lower affinity of new bone to implant surface (p = 0.046). The distal components of the two sides showed a similar trend for less new bone in the grooves and lower bone affinity of new bone in the distal composite-grafted components.

CONCLUSIONS

The current study suggests that supplementation of periprosthetic bone graft with bioactive ceramic particles may not help to promote healing of cementless implants under high dynamic loading conditions.

Successful canine patellar tendon reattachment to porous tantalum

The ability to achieve reattachment of soft tissues, such as tendon, directly onto a prosthetic surface would be of great benefit in case of periarticular bone loss or resection. Bone and potential soft tissue ingrowth using porous tantalum has been observed in prior animal studies. We hypothesized porous tantalum washers used to reattach canine patellar tendon to bone would provide sufficient strength to withstand physiologic loading. We reattached the released patellar tendon to the tibia using two porous tantalum washers in 33 skeletally mature dogs. Force plate analysis of gait, tensile testing of the tendon reconstruction, and histologic analysis of tissue ingrowth into the implants were performed after 3, 6, and 12 weeks' survival. Physiologic weightbearing on the operated leg had normalized 6 weeks after tendon reconstruction surgery. The mechanical strength of the tendon reattachment was 76% of the strength of the native tendon insertion by 6 weeks but did not increase further with time. Fibrous tissue occupied approximately 1/2 of the available space in the porous tantalum washers at all times. Our data suggest tendon healing into a prosthetic material can be achieved using porous tantalum washers with sufficient mechanical strength to withstand physiologic loading.

An institutional review of clear cell chondrosarcoma

Clear cell chondrosarcoma is a rare bone neoplasm with a slow progressive clinical course and infrequent metastasis, but with a high local recurrence rate. We sought to ascertain the long-term outcome of patients with this neoplasm and to identify possible factors predicting survival. Sixteen patients with clear cell chondrosarcomas treated at one institution and who had long-term clinical followup were identified. All patients were treated by surgical resection of the tumor, which was classified as clear (> 2 mm) in 10 patients and marginal or intralesional in six patients. Three patients had local recurrence after a median of 1.7 years. Metastatic disease developed in four patients with a median time to diagnosis of 8.1 years. Ten-year overall survival of patients with clear cell chondrosarcomas was 89%, and disease-free survival was 68%. Patients with surgical resections comprising clear margins had longer disease-free survival compared with patients with marginal and intralesional tumors. Inadequate surgical resection of clear cell chondrosarcoma leads to risk of local recurrence and metastatic disease. The malignancy has a tendency to metastasize relatively late, therefore, followup of patients is necessary after the generally accepted 5-year period.

LEVEL OF EVIDENCE

Prognostic study, Level III (case control study). See the Guidelines for Authors for a complete description of levels of evidence.

Biologic significance of surface microroughing in bone incorporation of porous bioactive glass implants

A novel chemical etching method was recently developed to create a controlled microrough surface on porous bioactive glass implants. Our earlier in vitro studies showed enhanced attachment of osteoblast-like MG63 cells on a microrough bioactive glass surface. The purpose of our current study was to confirm the in vivo significance of surface microroughening for bone bonding of bioactive glass. Porous bioactive glass cones made of sintered microspheres were surgically implanted in the anterior cortex of rabbit femurs. Peripheral quantitative computed tomography (pQCT), biomechanical push-out testing, histomorphometry, and electron microscopy (BEI-SEM) were used to analyze bone ingrowth and osseointegration at 7, 10, 14, 28, 56, and 84 days after implantation. The results showed that microroughening of the bioactive glass surface significantly enhanced the bone-bonding response of the biomaterial. The positive response was seen in one of the three bioactive glass compositions studied. The affinity index of new bone on the glass surface was significantly (p = 0.02) increased with a trend (p = 0.10) toward improved mechanical incorporation. New bone formation was dependent on the glass composition, and it was found to occur not only through the mechanism of bone ingrowth but also based on in situ osteogenesis within implant interstices. Based on these results, the procedure of microroughening could enhance the osteopromotive properties of certain bioactive glass compositions.

Molecular biologic comparison of new bone formation and resorption on microrough and smooth bioactive glass microspheres

In a recent in vitro study, chemical microroughening of a bioactive glass surface was shown to enhance attachment of MG-63 osteoblastic cells to glass. The current study was designed to delineate the effects of microroughening on the gene expression patterns of bone markers during osteogenesis and new bone remodeling on bioactive glass surface in vivo. With the use of a rat model of paired comparison, a portion of the medullary canal in the proximal tibia was evacuated through cortical windows and filled with microroughened or smooth bioactive glass microspheres. The primary bone-healing response and subsequent remodeling were analyzed at 1, 2, and 8 weeks, respectively, by radiography, pQCT, histomorphometry, BEI-SEM, and molecular biologic analyses. The expression of various genes for bone matrix components (type I collagen, osteocalcin, osteopontin, osteonectin) and proteolytic enzymes (cathepsin K, MMP-9) were determined by Northern analysis of the respective mRNAs. Paired comparison showed significant differences in the mRNAs levels for specific bone matrix components at 2 weeks: osteopontin was significantly higher (p =.01) and osteonectin significantly lower (p =.05) in bones filled with microroughened microspheres than in those filled with smooth microspheres. Bones filled with microrough microspheres also showed significantly increased ratios of cathepsin K and MMP-9 (both markers of osteoclastic resorption) to type I collagen (p =.02 and p =.02, respectively) at 2 weeks and a significantly increased expression of MMP-9 at 8 weeks (p =.05). The pQCT, histomorphometric, and BEI-SEM analyses revealed no significant differences in the pattern of bone-healing response. Based on these results, microroughening of a bioactive glass surface could trigger temporal changes in the expression of specific genes especially by promoting the resorption part of new bone-remodeling processes. Future studies are needed to evaluate if the observed changes of gene expression are directly related to the microrough surface of any biomaterial or are biomaterial specific.

Characterization of microrough bioactive glass surface: surface reactions and osteoblast responses in vitro

The current study characterized the in vitro surface reactions of microroughened bioactive glasses and compared osteoblast cell responses between smooth and microrough surfaces. Three different bioactive glass compositions were used and surface microroughening was obtained using a novel chemical etching method. Porous bioactive glass specimens made of sintered microspheres were immersed in simulated body fluid (SBF) or Tris solutions for 1, 6, 24, 48, or 72 h, and the formation of reaction layers was studied by means of a scanning electron microscope/energy dispersive X-ray analysis (SEM/EDXA). Cell culture studies were performed on bioactive glass disks to examine the influence of surface microroughness on the attachment and proliferation of human osteoblast-like cells (MG-63). Cell attachment was evaluated by means of microscopic counting of in situ stained cells. Cell proliferation was analyzed with a nonradioactive cell proliferation assay combined with in situ staining and laser confocal microscopy. The microroughening of the bioactive glass surface increased the rate of the silica gel layer formation during the first hours of the immersion. The formation of calcium phosphate layer was equal between control and microroughened glass surfaces. In cell cultures on bioactive glass, the microrough surface enhanced the attachment of osteoblast-like cells but did not have an effect on the proliferation rate or morphology of the cells as compared with smooth glass surface. In conclusion, microroughening significantly accelerated the early formation of surface reactions on three bioactive glasses and had a positive effect on initial cell attachment.

Creation of microrough surface on sintered bioactive glass microspheres

Bioactive glasses are surface-active, generally silica-based, synthetic materials that form a firm chemical bond to bone. The aim of this study was to further enhance the bioactivity of glasses by creating a microroughness on their surface. Microroughness increases potential surface area for cell attachment and biomaterial-cell interactions. Three bioactive glasses of different composition were studied. Each material was flame-sprayed into microspheres, and a selected fraction of the spheres (250-300 microm) was sintered to form porous bioactive glass specimens. To create microrough surfaces, different acid etching techniques were tested. Atomic force microscopy (AFM) and back-scattered electron imaging of scanning electron microscopy (BEI-SEM) were used to characterize surface roughness. The degree of roughness was measured by AFM. A novel chemical-etching method, developed through intensive screening of different options, was found consistently to create the desired microroughness, with an average roughness value (R(a)) of 0.35-0.52 microm and a root mean-square roughness value (R(rms)) of 0.42-0.64 microm. Microroughening of the glass surface was obtained even in the internal parts of the porous glass matrices. Measured by BEI-SEM, the etching of a bioactive glass surface did not interfere with the formation of the characteristic surface reactions of bioactive glasses. This was confirmed by immersing the etched and control glass bodies in a simulated body fluid and tris(hydroxymethyl) aminomethane/HCl. The etching process did not significantly affect the mechanical strength of the sintered bioactive glass structures. Based on these experiments, it seems possible to create a reproducible microroughness of appropriate size on the surface of porous bioactive glass. The biologic benefits of such a surface treatment need to be validated with in vivo experiments.