How reliable is the high-volume definition in prostate cancer patients: the potential game-changing role of PSMA.

PURPOSE: To evaluate whether metabolic and volumetric data from 68 Ga-PSMA PET/CT performed during staging of de-novo high-volume mCSPC patients who received docetaxel could be used to predict survival. METHODS: Forty-two de-novo high-volume mCSPC patients, who received ADT + Docetaxel and underwent 68 Ga-PSMA PET/CT for staging, were included in the study. The association between patients' pathological data, all PSA measurements, treatments they received, the data obtained from 68 Ga-PSMA PET/CT and progression-free and overall survival were examined. RESULTS: In the multivariate analysis, PSMA-TV (primary) and PSMA-TV (WB) variables were shown to be independent negative predictors of overall survival. For the threshold value of 19.91 cm 3 obtained for PSMA-TV (primary), HR was calculated as 6.31, the 95% confidence interval (CI): 1.01-39.18, P = 0.048. For the threshold value of 1226.5 cm 3 obtained for PSMA-TV (WB) variable, HR was calculated as 58.62, the 95% CI: 2.55-1344.43, P = 0.011. In our study, SUVmax (WB) variable was found to be an independent and negative predictor of progression-free survival. For the determined threshold value of 17.74, HR was calculated as 16.24, 95% CI: 1.18-22.76, P = 0.037. CONCLUSION: Metabolic and volumetric data obtained from 68 Ga-PSMA PET/CT can be used to predict survival in de-novo high-volume mCSPC. Our results show that in ADT + Docetaxel receiving patients, a subgroup with higher PSMA-TV (WB) values have a significantly worse prognosis. This situation suggests that the high-volume disease definition in the literature may be insufficient for this group, and that 68 Ga-PSMA PET/CT can play an essential role in demonstrating the heterogeneity within the group.

Comparison of Radioactive Iodine Activities in Terms of Short- and Long-term Results in Ablation Therapy in Patients with Low-risk Differentiated Thyroid Cancer.

Objectives: The aim of this study was to compare the treatment responses after ablation with 30-50 mCi radioactive iodine (RAI) and 100 mCi RAI in patients with differentiated thyroid cancer (DTC) who were in the low-risk group according to 2015 American Thyroid Associations Classification (ATA 2015) criteria. Methods: Between February 2016 and August 2018, 100 patients who received RAI treatment in our clinic after total thyroidectomy and who were in the low-risk group DTC were included in this retrospective study. These patients were divided into 2 groups: low-activity (30-50 mCi) (group 1) and high-activity (100 mCi) (group 2). While 54 patients were treated with low activity, 46 patients received high activity RAI. The 2 groups were compared according to the 1st- and 3rd-year treatment response status. Results: According to the first-year follow-up, 15 patients were accepted as indeterminate response and 85 patients as excellent response. Three (5.5%) of the patients who were accepted as indeterminate response were in group 1 and 12 (26%) were in group 2. According to the third year follow-up, 1 patient in group 1 and 3 patients in group 2 were accepted as indeterminate response. No biochemical incomplete response or recurrent disease was detected. In the chi-square analysis performed to investigate the relationship between the first-year treatment response and RAI activities, a significant relationship was found (p=0.004). In the Mann-Whitney U test performed to investigate the parameters that may be effective in the treatment response, only the preablative serum thyroglobulin value was shown to have a significant difference between the two groups (p=0.01). In the long-term follow-up of the patients, based on the third year treatment response data, chi-square analysis was performed to evaluate the two groups in terms of treatment responses, and no statistically significant relationship was found (p=0.73). Conclusion: Ablation with 30-50 mCi can be safely applied in DTC patients who are in the ATA 2015 low-risk group and are planned for RAI ablation treatment.

Can 68Ga-PSMA PET/CT-derived prostate-specific membrane antigen expression parameters predict prostate-specific antigen response to enzalutamide treatment?

OBJECTIVE: In patients with metastatic castration-resistant prostate cancer (mCRPCa), enzalutamide is administered when docetaxel treatment fails. The purpose of the study was to evaluate the relationship between prostate-specific antigen (PSA) response and metabolic parameters obtained from 68Ga-PSMA PET/CT before treatment in this patient group. METHODS: From February 2018 to May 2020, 34 patients with mCRPCa were enrolled in this study. The association between PSA response (at least 50% decrease compared to the pretreatment value) and quantitative prostate-specific membrane antigen (PSMA) expression parameters such as SUVmax, SUVmean, PSMA-TV (PSMA receptor-expressing tumor volume) and TL-PSMA (total lesion PSMA receptor expression) were evaluated. RESULTS: Mean SUVmax, SUVmean, PSMA receptor-expressing tumor volume (PSMA-TV) and total lesion PSMA receptor expression (TL-PSMA) values were 33.66 ± 20.42; 8.82 ± 5.03; 319.85 ± 615.12 cm3; and 2894.76 ± 5195.13, respectively. In the posttreatment 12th week, 22 patients (64.7%) had PSA response, while 12 patients (35.3%) were nonresponders. In patients with PSA response, PSMA-TV values were significantly lower than nonresponders (78.37 ± 80.99 cm3 vs. 451.58 ± 734.61 cm3; P = 0.028). But there was no significant difference between responders and nonresponders in terms of age, ISUP grade, SUVmax, SUVmean, TL-PSMA, pretreatment PSA values, presence of local recurrence or metastases at any site. CONCLUSION: PSMA-TV values on 68Ga-PSMA PET/CT imaging before starting enzalutamide treatment following docetaxel failure can predict PSA response in patients with mCRPCa.

Correlations of the 68Ga-PSMA PET/CT derived primary prostate tumor PSMA expression parameters and metastatic patterns in patients with Gleason Score >7 prostate cancer.

OBJECTIVE: We aimed to investigate the correlations between the prostate specific membrane antigen (PSMA) expression parameters of the primary prostate tumor on gallium-68 (68Ga)-PSMA positron emission tomography/computed tomography (PET/CT) with metastatic patterns in patients with Gleason Score (GS) >7 prostate cancer (PCa). MATERIALS AND METHODS: This study included 55 PCa patients who had 68Ga-PSMA PET/CT performed for staging. According to metastatic pattern, patients were divided into 3 groups as non-metastatic (N0M0), those with isolated pelvic lymph node metastasis (N1M0) and with distant metastasis (M1). The correlations between the primary tumor PSMA expression parameters such as maximum standardize uptake value (SUVmax), SUVmean, PSMA-TV (PSMA receptor expressing tumour volume), and TL-PSMA (total lesion PSMA receptor expression) on 68Ga-PSMA PET/CT imaging and metastatic patterns were investigated. RESULTS: There were 21, 9 and 25 patients in the N0M0, N1M0 and M1 groups, respectively. The PSMA-TV and TL-PSMA values were significantly higher in the N1M0 and the M1 patient groups compared to the N0M0 group, but there was no significant difference between the N1M0 and M1 groups. The primary tumor SUVmax and SUVmean values were not significantly different between the three groups. The optimal PSMA-TV cut-off value for metastasis was >8.07cm3 (AUC 0.86) with sensitivity of 76.5% and specificity 85.7%. The optimal TL-PSMA cut-off value for metastasis was >93 (AUC 0.74) with sensitivity of 64%, and specificity 100%. CONCLUSION: The PSMA-TV and TL-PSMA values are strong markers for metastasis prediction in patients with GS >7 PCa but no other PSMA expression parameters can distinguish between N1M0 and M1 groups.

The Predictive Value of Proportional Evaluation Based on the Metabolic Activity of Cervical Lymph Nodes on PET/CT Imaging in Patients with Larynx Cancer.

OBJECTIVES: We aimed to evaluate the proportional values of maximum standardized uptake value (SUVmax) for cervical lymph nodes on 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for prediction of the presence of metastasis in patients with larynx squamous cell cancer (LSCC). METHODS: This retrospective study involved 43 patients with LSCC. All patients underwent resection of the primary tumor and neck dissection within 4 weeks after undergoing 18F-FDG PET/CT examinations. Receiver operating characteristic (ROC) analysis was performed to evaluate the lymph node SUVmax/primary tumor SUVmax (SUVmaxLN/SUVmaxPT), lymph node SUVmax/aortic SUVmax (SUVmaxLN/SUVmaxA), and lymph node SUVmax/ liver SUVmax (SUVmaxLN/SUVmaxL) ratios for diagnosis of lymph node metastasis. RESULTS: SUVmaxLN/SUVmaxA, SUVmaxLN/SUVmaxL, and SUVmaxLN/SUVmaxPT rates were significantly higher in metastatic lymph nodes compared to non-metastatic nodes. ROC analysis for metastasis showed that the cut-off thresholds were 3.87 for SUVmaxLN; 1.78 for SUVmaxLN /SUVmaxA; 1.08 for SUVmaxLN/SUVmaxL; and 0.36 for SUVmaxLN/SUVmaxPT. The diagnostic sensitivity, specificity and AUC were 83.7%, 77%, 0.856 for SUVmaxLN; 79.7%, 84%, 1.78 for SUVmaxLN/SUVmaxA; 84.1%, 76%, 0.833 for SUVmaxLN/SUVmaxL; and 53.6%, 76%, 0.666 for SUVmaxLN/SUVmaxPT, respectively. CONCLUSION: SUVmaxLN/SUVmaxA, SUVmaxLN/SUVmaxL, and SUVmaxLN/SUVmaxPT ratios can be safely used for diagnosis of cervical lymph node metastasis in patients with LSCC.

Ileal Neuroendocrin Tumor Metastasis to Breast Diagnosed with Ga-68 DOTATATE PET/CT

Breast metastasis of the well differentiated neuroendocrin tumor (WDNET) of the ileum is very rare. A case of a 62-year-old woman with ileal WDNET, who underwent restaging with Ga-68 DOTATATE PET/CT due to progression of metastatic lesions under the treatment with somatostatin analog and mammalian target of rapamycin inhibitors. Ga-68 DOTATATE PET/CT demonstrated intense increased uptake in the subsantimetric nodular lesion in the upper outer quadrant of the left breast. The histopathologic findings obtained by tru-cut biopsy revealed WDNET metastasis (Ki-67 proliferation index 1%).

The comparison of arthroscopic acromioplasty with and without acromioclavicular coplaning.

BACKGROUND: Coplaning means the removal of medial acromial spurs and inferior aspect of the distal clavicle. The aim of the study was to evaluate the outcomes of arthroscopic acromioplasty with and without coplaning in patients without acromioclavicular (AC) joint arthritis. METHODS: Because of impingement syndrome, arthroscopic subacromial decompression and acromioplasty was performed in Group 1 (9 males/31 female). In addition, coplaning was performed in Group 2 (8 males/21 females) by two different surgeons. The mean age was 48 in Group 1, 46 in Group 2. The mean follow-up was 50 months and 44 months, respectively. RESULTS: Constant score, cross-body adduction test and AC joint tenderness was used for follow-up. The mean preoperative Constant scores were 45 points (range: 34-76 points) in Group 1, 39 points (range: 32-69 points) in Group 2. The mean Constant scores at the latest follow-up was 78 points (range: 68-100 points) for Group 1, 84 points (range: 72-100 points) for Group 2. There was no statistically difference between two groups at the latest follow-up (p<0.05). In two patients in Group 2, cross-body adduction test was positive but asymptomatic. CONCLUSION: Excision of the inferior side of the lateral clavicle to the level of the acromion with minimal disruption of the joint capsule does not develop AC joint symptoms in long-term follow-up.

Foreseeing the danger in the beach chair position: Are standard measurement methods reliable?

PURPOSE: The aim of this study is to show whether peripheral perfusion monitoring methods reflect central perfusion during shoulder arthroscopy at beach chair position. We hypothesized that mean arterial pressure (MAP), central heart rate (CHR) and peripheral oxygenation (SaO2) measurements individually will not parallel cerebral oximetry measurements by near-infrared spectroscopy (NIRS). METHODS: Between 2011 and 2012, 53 patients who had arthroscopic rotator cuff repair surgery in the beach chair position were enrolled prospectively. Median ages of the patients were 58 (range 42-68) years. The regional cerebral oxygen saturation value of each hemisphere was continuously monitored by the use of NIRS. MAP, CHR, SaO2 and both hemispheric cerebral oxygen saturation values were recorded at six time periods peri-operatively. Correlation and differences between parameters were evaluated. RESULTS: Cerebral oxygen saturation of right hemisphere was dropped >20 % in 28.3 and 45.3 % of the patients. At left hemisphere, cerebral oxygen saturation was dropped >20 % in 20.8 and 43.4 % of the patients. Peripheral saturation values were statistically different from cerebral saturation values (p < 0.001). On the other hand, there was a correlation between cerebral saturation and MAP values (p < 0.05). CONCLUSION: Cerebral oximetry by NIRS may prove useful as a monitor for cerebral ischaemia. In the absence of NIRS, CHR can partially detect abnormalities but not trustable, and MAP is the most reliable method for monitoring.

Technique of Kirschner wire reduction and fixation of displaced two-part valgus angulated proximal humerus fractures at the surgical neck.

This article describes the technique of closed reduction with percutaneous fixation using Kirschner wires in helping the reduction of two-part valgus angulated and displaced proximal humerus fractures at the surgical neck. Traditional open reduction may lead to more accurate anatomic reduction; however, extensive tissue dissection increases the risk of avascular necrosis. Thus, closed reduction of unstable fracture mostly required forceful reduction maneuvers, which can harm the vascular supply and increase hematoma formation. Reduction of the fractured sides can easily be performed by engaging Kirschner -wires with a joystick method and fixation can be secured by using threaded pins. Thirty-six consecutive patients with displaced, two-part, valgus-angulated proximal humerus fractures at the surgical neck were treated by this method. The patients were followed for an average of 38 months. All fractures healed. According to the Constant scoring system, 21 patients (58%) had excellent, 9 patients (25%) had good, and 6 patients (17%) had fair results. The technique of closed reduction with a joystick method and percutaneous fixation is regarded as a reasonable treatment alternative in displaced two-part valgus angulated proximal humerus fracture.

Single-row versus double-row arthroscopic rotator cuff repair in small- to medium-sized tears.

HYPOTHESIS: Double-row rotator cuff repair leads to superior cuff integrity and clinical results compared with single-row repair. MATERIALS AND METHODS: The study enrolled 68 patients with a full-thickness rotator cuff tear who were divided into 2 groups of 34 patients according to repair technique. The patients were followed-up for at least 2 years. The results were evaluated by Constant score. DISCUSSION: Despite the biomechanical studies and cadaver studies that proved the superiority of double-row fixation over single-row fixation, our clinical results show no difference in functional outcome between the two methods. It is evident that double-row repair is more technically demanding, expensive, and time-consuming than single-row repair, without providing a significant improvement in clinical results. RESULTS: Comparison between groups did not show significant differences. At the final follow-up, the Constant score was 82.2 in the single-row group and 78.8 in the double-row group. Functional outcome was improved in both groups after surgery, but the difference between the 2 groups was not significant. CONCLUSIONS: At long-term follow-up, arthroscopic rotator cuff repair with the double-row technique showed no significant difference in clinical outcome compared with single-row repair in small to medium tears.

The use of screw at the fracture level in the treatment of thoracolumbar burst fractures.

STUDY DESIGN: In this prospective randomized study, the results of treating unstable thoracolumbar burst fractures by pedicle instrumentation with and without fracture level screw combination were given. OBJECTIVE: Our aim was to evaluate the efficacy of fracture level screw combination in achieving and maintaining correction in the treatment of unstable thoracolumbar burst fractures. SUMMARY OF BACKGROUND DATA: Most authors reported that intraoperative correction of sagittal deformity is important for the maintenance of fracture reduction and is one of the most consistent predictor of satisfactory functional outcome. METHODS: Seventy-two patients with unstable thoracolumbar burst fractures were randomized into 4 groups with equal number of patients. In group 1, patients were treated by segmental posterior instrumentation with 2 levels above and 2 levels below the fracture level fixation, in group 2 they were treated as in group 1 with fracture level screw incorporation. In group 3, patients were treated by short-segment posterior instrumentation with 1 level above and 1 level below, in group 4 they were treated by short-segment posterior instrumentation with fracture level screw incorporation. Clinical and radiologic parameters were evaluated before surgery, after surgery, and at follow-up. RESULTS: The average follow-up was 50 months. Fracture level screw combination provided better intraoperative correction and maintenance in the treatment of unstable thoracolumbar burst fractures, which was more prevalent in short-segment fixation group. CONCLUSIONS: Reinforcement with fracture level screw combination can help to provide better kyphosis correction and offers immediate spinal stability in patients with thoracolumbar burst fracture.

[Unusual migration of K-wire following fixation of clavicle fracture: a case report]. / Klavikula kirigi internal fiksasyonu sonrasinda K-telinin atipik migrasyonu: Olgu sunumu.

The migration of various internal fixation devices, especially Kirshner (K) wires, is well established. The wires usually follow a retrograde path, protruding near the entry point. When they migrate in the other direction, serious problems may occur. Migration of K-wires to the lung, heart, spleen, subclavian artery, pulmonary artery and aorta have been reported in a few cases. A 26-year-old male with chest pain was seen in our clinic. The patient had been operated for left distal clavicle fracture two years before. No abnormality was noted on the physical examination. Radiographs showed migration of the wire outside the clavicle across the sternum to the opposite hemithorax. The pin was removed through the incision over the sternum under direct vision with thoracoscope. The pin was extrapleurally located. There was no additional morbidity attributed to thoracoscopy or chest tube. In conclusion, K-wires can easily migrate, resulting in serious complications. Close follow-up should be done after internal fixation.

No difference between knotless sutures and suture anchors in arthroscopic repair of Bankart lesions in collision athletes.

The purpose of this study was to compare the clinical results of knotless and knot-tying suture anchors in arthroscopic Bankart repair of collision athletes. Thirty-eight athletes underwent arthroscopic Bankart repairs. The mean age of the patients at the time of surgery was 23 years. Bio-Knot-tying anchors were used in 18 patients, and Bio-Knotless suture anchors were used in 20 patients. Preoperative and postoperative evaluations were performed by Rowe scores. At the end of 40 months follow-up, both the knot-tying and the knotless suture anchor groups had similar postoperative results. There were no differences between Knot-Tying and Knotless repair about late disengagement and re-dislocation in this patient group. Knotless repair provided secure and low-profile repair without introducing complexities to the procedure of arthroscopic knot tying one.

Quantification of acromioclavicular reduction parameters after the Weaver-Dunn procedure.

BACKGROUND: The combination of the reconstruction of the coracoclavicular ligaments with the resection arthroplasty of the distal end of the clavicle is a commonly used technique in acromioclavicular separations. HYPOTHESIS: The purpose of the current study was to quantify the reduction parameters using 3-D CT and to analyze their effects on clinical outcomes. STUDY DESIGN: Case series. METHODS: The patients with chronic symptoms after acromioclavicular dislocation (type III) were treated with reconstruction of the coracoclavicular ligaments. The average follow-up was 69.5 months. The patient group consisted of 21 men and 8 women. The initial treatment at the time of injury was nonoperative in 26 of 29 patients. CT was used to document anteroposterior (APD), craniocaudal (CCD) and mediolateral (MLD) acromioclavicular reduction parameters. Constant Shoulder scoring system was used. RESULTS: The mean preoperative Constant score was 56.62 +/- 18.63 points while the postoperative score was 89.93 +/- 10.79 points. The mean APD was 9.2 mm, the mean CCD was 1.1 mm and the mean MLD was 8.4 mm. There was no correlation between the APD, MLD and the Constant Scores. However, an inverse correlation between the CCD and the postoperative Constant Scores was found. CONCLUSIONS: CCD plays an important role on the postoperative function. If the CCD is larger, the Constant score is lower. CLINICAL RELEVANCE: The reduction loss is a distinctive parameter of the functional outcome, even when the reconstructed coracoclavicular ligament is intact. Secure fixation may be achieved with techniques preserving CCD.

Arthroscopic inspection after the surgical treatment of patella fractures.

After the treatment of patella fractures the only way to evaluate healing at the articular surface before implant removal is through arthroscopy. The purpose of this study was to examine the healing potential of the cartilage. Arthroscopy was performed in 18 patients at the time of implant removal. The mean age of the patients was 42.1 years. The time elapsed from the index surgery to the arthroscopy and implant removal surgery was 12.9 months. During the arthroscopy, we inspected articular step-off, cartilage loss, and joint surface irregularities. Cartilage irregularities were observed in 13 of the 18 patients. Five patients had well-healed cartilage at the patellar surface. Although none of the patients had displacement at final follow-up X-rays, step-off was detected in two patients during arthroscopy. Our observation showed that cartilage lesions did not correlate with clinical and radiological evaluation. Despite good knee scores, we observed surface irregularities, chondral lesions, and fibrillation in most of the cases implicating subsequent patellofemoral arthritis.

Arthroscopic repair of radial lateral meniscus [corrected] tear by double horizontal sutures with inside-outside technique.

The purpose of this prospective study is to report the outcome of arthroscopic repair of radial lateral meniscus tears at the junction of the anterior horn and body. Five patients with an average age of 27 years were treated. The repair was performed with double horizontal sutures by inside-out technique, using zone-specific, curved cannulae with no enhancement technique. A mean of 2.4 superior and 2.8 inferior stitches were performed. Reduction was obtained in all cases. Patients were evaluated using Lysholm functional knee scores. All patients were clinically and radiologically examined using MRI to assess meniscus integrity at the repair site, over an average follow-up period of 31 months. All patients were able to return to their former level of activity. In all cases, MRI showed a fully healed meniscus at the repair sites, with no further disruption of the debrided area. The mean Lysholm scores improved from 62 preoperatively to 94 postoperatively. The difference between preoperative and postoperative values was found to be statistically significant (p=0.029). No cases of postoperative extra or intra-articular complications were encountered. We found that repairing rather than resecting radial lateral meniscus tears that extend into capsular zone, improves activity level.

A positioning technique for closed intramedullar nailing of tibia fractures.

BACKGROUND: We described a method of positioning the patient on the standard operation table that enables manual traction and equipment that is available in almost all operating theaters and compared it with regular positioning technique. METHODS: Eighty two patients with unstable unilateral tibia fractures were evaluated and treated in the author's clinic between July 2002 and June 2006. The average age of the patients was 40.6 (29-65) years. The surgical indications included uncomplicated closed fractures, fractures in patients with multiple injuries, and inability to maintain a satisfactory closed reduction. Forty-two fractures that were operated with the new technique and meet these criteria's were included in the study. All operations were performed on normal operation tables. RESULTS: There was not any case of failure related with the nailing and the presented positioning technique. Intraoperative reduction was achieved with closed method in all patients. In 10 patients, satisfactory reduction was achieved with the help of polar screws in 2 patients and cable system in 8 patients. Anatomic reduction was obtained in the rest of 32 patients. There were no cases of compartment syndrome diagnosed postoperatively in both injured and uninjured side. There were also no neurologic complications and postoperative infection formation related to surgery. CONCLUSION: The advantages of this technique is that, it allows precise reduction, control of rotation, and easy imaging access, without increasing operating or screening time and complication.

Incidence of chondral lesions of talar dome in ankle fracture types.

BACKGROUND: Although the surgical treatment of ankle fractures is well known, a paucity of literature exists correlating chondral lesions with ankle fracture types. MATERIALS AND METHODS: This study is a retrospective review of patients with absence or presence of chondral lesions that underwent arthroscopically assisted open reduction and internal fixation between June 2002 and April 2005. There were 38 female and 48 male patients (mean age, 41.4 years; mean followup, 33.9 months), and all had an Ankle-Hindfoot Scale score. The relationship between fracture types and presence of lesions was evaluated. RESULTS: Four of 27 fractures with chondral lesions consisted of the bimalleolar type, 6 of 15 fractures with chondral lesions consisted of the trimalleolar type, and 14 of 20 distal fibula fractures had chondral lesions. There was significant greater incidence of chondral lesions associated with distal fibula fractures. The mean AOFAS score was 95.6 among all fractures. CONCLUSION: There is clear evidence that despite anatomic reduction, postoperative results of ankle fracture repair are not free of complications. We believe inspection of the talar dome should be routinely considered in the surgical repair ankle fractures.

The effect of overlapping on the primary stability of osteochondral grafts in mosaicplasty.

Our goal was to determine the primary stability of overlapping osteochondral grafts used in mosaicplasty by studying the effect of overlapping in an ex vivo model. Osteochondral grafts, 10 mm in diameter, were transplanted from the trochlea of cow femurs to the weight-bearing area of the lateral femoral condyle with 0, 15, or 30% overlap. The grafts were pushed in with a probe at a rate of 2 mm/min, and load (N)-displacement (mm) curves were recorded. In Group I (control, 0% overlap), insertion 1 and 2 mm below the cartilage level could be reached at 572.3 +/- 273.6 and 999.3 +/- 427.6 N, respectively. In Group II (15% overlap), insertion 1 and 2 mm below the cartilage level could be reached at 263.6 +/- 91.7 and 746.6 +/- 88.0 N, respectively. In Group III (30% overlap), insertion 1 and 2 mm below the cartilage level could be reached at 179.4 +/- 31.2 and 657.0 +/- 106.5 N, respectively. The loads that were necessary to produce a 1-mm dent in the grafts were significantly different between Groups I and II and Groups I and III (p < 0.05). These results suggest that stability may be reduced by graft overlapping in mosaicplasty surgery. The results of this ex vivo animal study contribute to a more complete understanding of the primary stability of osteochondral grafts in an overlapping position as well as postoperative protocols.