• Clinics in Shoulder and Elbow
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• v.26 no.3
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• pp.287-295
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• 2023

Background: Posterolateral rotatory instability (PLRI) is a common mechanism of recurrent elbow instability. While the essential lesion is a deficiency in the lateral ulnar collateral ligament (LUCL), there are often associated concomitant bony lesions, such as an Osborne-Cotterill lesions (posterior capitellar fractures) and marginal radial head fractures, that compromise stability. Currently, there is no standard treatment for posterior capitellar deficiency associated with recurrent PLRI. Methods: We conducted a retrospective review of five patients with recurrent PLRI of the elbow associated with a posterior capitellar impaction fracture engaging with the radial head during normal range of motion. The patients were treated surgically with LUCL reconstruction or repair and off-label reconstruction of the capitellar joint surface using a small metal prosthesis designed for metatarsal head resurfacing (HemiCAP toe classic). Results: Five patients (three adolescent males, two adult females) were treated between 2007 and 2018. At a median follow-up of 5 years, all patients had complete relief of their symptomatic instability. No patients had pain at rest, but two patients had mild pain (visual analog scale 1-3) during physical activity. Three patients rated their elbow as normal, one as almost normal, and one as greatly improved. On short-term radiographic follow-up there were no signs of implant loosening. None of the patients needed reoperation. Conclusions: Recurrent PLRI of the elbow associated with an engaging posterior capitellar lesion can be treated successfully by LUCL reconstruction and repair and filling of the capitellar defect with a metal prosthesis. This treatment option has excellent clinical results in the short-medium term. Level of evidence: IV.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.6
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• pp.664-670
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• 2004

Statement of problem. One of the common problems of dental implant prosthesis is the loosening of the screw that connects each component, and this problem is more common in single implant-supported prostheses with external connection. Purpose. The purpose of this study was to examine the changes of detorque values of abutment screws with external connection in different abutment heights. Materials and methods. After cyclic loading on three different abutment heights, detorque values were measured. Abutments were retained with titanium abutment screws tightened to 30 Ncm (30.5 kgmm) with digital torque gauge as recommended by the manufacturer. Replacing abutments, implants and titanium abutment screws with new ones at every measurement, initial detorque values were measured six times. In measuring de torque values after cyclic loading, Avana Cemented Abutments of 4.0 mm collar, 7.0 mm height (Osstem Co., Ltd., Seoul, Korea) were used with three different lengths of 5.0, 8.0, 11.0 mm. Shorter abutments were made by milling of 11.0 mm abutment to have the same force-exercised area of 4.5 mm diameter. Sine curve force (20N-320N, 14Hz) was applied, and detorque values were measured after cyclic loading of 2 million times by loading machine. Detorque values of initial and after-loading were measured by digital torque gauge. One-way ANOVA was employed to see if there was any influence from different abutment heights. Results. The results were as follows: 1. The initial detorque value was 27.8$\pm$0.93 kgmm, and the ratio of the initial detorque value to the tightening torque was 0.91(27.8/30.5). 2. Measured detorque values after cyclic loading were declined as the height of the abutment increased, that was, 5.0 mm; 22.3$\pm$0.82 kgmm, 8.0 mm; 21.8$\pm$0.93 kgmm, and 11.0 mm; 21.3$\pm$0.94 kgmm. 3. One-way ANOVA showed no statistically significant differences among these (p>0.05). 4. Noticeable mobility at the implant-abutment interface was not observed in any case after cyclic loading at all.

• Advances in Computational Design
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• v.4 no.3
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• pp.295-305
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• 2019

The sealing cement of total hip arthroplasty is the most widely used binder in orthopedic surgery for anchoring implants to their recipient bones. Nevertheless, this latter remains a fragile material with weak mechanical properties. Inside this material cracks initiate from cavities. These cracks propagate under the effect of fatigue and lead to the failure of this binder and consequently the loosening of the prosthesis. In this context, this work consists to predict the position of cracks initiation and their propagations path using the Extended Finite Element Method (XFEM). The results show that cracks can only be initiated from a sharp edges of an ellipsoidal cavity which the ratio of the minor axis over the major axis is equal to 0.1. A maximum crack length of 19 ?m found for a cavity situated in the proximal zone position under a static loading. All cracks propagate in same(almost) way regardless of the cavity(site of initiation) position and its inclination in the proximal zone.

• Biomaterials Research
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• v.22 no.4
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• pp.259-270
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• 2018

Background: Total hip arthroplasty (THA) is probably one of the most successful surgical interventions performed in medicine. Through the revolution of hip arthroplasty by principles of low friction arthroplasty was introduced by Sir John Charnley in 1960s. Thereafter, new bearing materials, fixation methods, and new designs has been improved. The main concern regarding failure of THA has been the biological response to particulate polyethylene debris generated by conventional metal on polyethylene bearing surfaces leading to osteolysis and aseptic loosening of the prosthesis. To resolve these problems, the materials of the modern THA were developed since then. Methods: A literature search strategy was conducted using various search terms in PUBMED. The highest quality articles that met the inclusion criteria and best answered the topics of focus of this review were selected. Key search terms included 'total hip arthroplasty', 'biomaterials', 'stainless steel', 'cobalt-chromium', 'titanium', 'polyethylene', and 'ceramic'. Results: The initial search retrieved 6921 articles. Thirty-two articles were selected and used in the review. Conclusion: This article introduces biomaterials used in THA and discusses various bearing materials in currentclinical use in THA as well as the newer biomaterials which may even further decrease wear and improve THA survivorship.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2002.10a
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• pp.125-134
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• 2002

This is a prospective study in which we evaluate the 5-10 year results of BiPolar shoulder arthroplasty in 64 patients (71 shoulders) with primary glenohumeral osteoarthritis. Fifty two patients (56 shoulders) were followed for greater than 60 months (average 79months)1 and no patients were lost to follow Lip. The average age of the patient at operation was 72.5 years. The UCLA score increased from 10.8 preoperatively to 25,7 postoperatively. The final Constant score in this elderly subset of patients averaged $65\%$ (unadjusted). Eighty seven percent of patients were satisfied with their final result. Excellent pain relief was achieved with a VAS of 2.5 (0=no pain, 15=excruciating pain). Active anterior forward flexion improved from $45^{\circ}$ to $104^{\circ}$. Seventy five percent of patients reveal persisting head-shell motion at an average of 7 years. There were two reoperations because of humeral stem loosening; both stems should have been cemented at the initial arthroplasty. It is demonstrated that BiPolar shoulder arthroplasty is durable over time, with clinical results equivalent to that in the literature when compared with hemiarthroplasty and total shoulder replacement.

• Clinics in Shoulder and Elbow
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• v.14 no.1
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• pp.105-110
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• 2011

Purpose: The purpose of this article is to identify and understand the complications of RTSA and to review the current methods of preventing and treating this malady. Materials and Methods: Previous constrained prostheses (ball-and-socket or reverse ball-and-socket designs) have failed because their center of rotation remained lateral to the scapula, which has limited of the motion of the prostheses and produced excessive torque on the glenoid component, and this leads to early loosening. The Grammont reverse prosthesis imposes a new biomechanical environment for the deltoid muscle to act, thus allowing it to compensate for the deficient rotator cuff muscles. Results: The clinical experience does live up to the lofty biomechanical concept and expectations: the reverse prosthesis restores active elevation above $90^{\circ}$ in patients with a cuff-deficient shoulder. However, external rotation often remains limited and particularly in patients with an absent or fat-infiltrated teres minor. Internal rotation is also rarely restored after a reverse prosthesis. Failure to restore sufficient tension in the deltoid may result in prosthetic instability. Conclusion: Finally, surgeons must be aware that the results are less predictable and the complication/revision rates are higher in revision surgery than that in the first surgery. A standardized monitoring tool that has clear definitions and assessment instructions is surely needed to document and then prevent complications after revision surgery.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.23 no.1
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• pp.34-40
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• 2014

There are several treatment options for rehabilitation of partial edentulism including the use of conventional or implant-retained fixed prostheses. However, such prosthetic options cannot always be possible because of compromised general and oral health (i.e. loss of supporting tissues, medical reasons, extensive surgical protocol and osseointegration failure of dental implant) as well as the affordability of patients. In some cases, removable partial denture provides easier access for oral hygiene procedures and the ability to correct discrepancies in dental arch relationships than implant fixed prosthesis. Recently, Implant Supported Removable Partial Denture (ISRPD) where to place dental implant in strategic position has been suggested to improve the limitation and shortcomings of conventional RPD. ISPRD can overcome mechanical limition of conventional RPD by placing implant in a favorable position and can be cost-effective, prosthetic solution for partially edentulous patients who are not immediate candidates for extensive, fixed implant supported restorations. Incorporation of dental implants to improve the RPD support and retention and to enhance patient acceptance should be considered when treatment planning for RPD. In this case, 59 years old male patient who received dental treatment of implant fixed prosthesis on both side of the upper jaw and implant overdenture on lower jaw showed implant abutment screw fracture on #15i and osseointegration failure on multiple number of implants. After removing failed implants, we planned ISRPD using #15i,24i,25i,26i and #23 natural tooth for RPD abutment. We fabricated #23 surveyed crown,#24i=25i=26i surveyed bridge and #15i gold coping for support,retention and stability for RPD. Periodic follow up check for 2years has been performed since the ISRPD delivery to the patient. No sign of screw loosening, fracture or bone resorption around abutment implants were detected.

• The Journal of the Korean bone and joint tumor society
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• v.11 no.2
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• pp.134-140
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• 2005

Purpose: We evaluated the effectiveness of temporary using the extendible external fixator (EF) for lengthening of soft tissue that contracture caused by tumor prosthesis removal in the treatment of complications after limb salvage surgery like deep infection and loosening. Materials and Methods: Five patients six cases were included who underwent extendible EF (Dyna-extor(r)). EF was applied after insertion of half pin to the proximal and distal bone of defect area. EF lengthening started at third day of post-operation, above 2-3 mm per day in the range of no neurological sign. Results: The treatment area was three in femur and two in tibia. Mean age when the time of EF apply was 22.2 years old (range 15-29), but its primary limb salvage operation had done in 13.4 years old (range 9-19), therefore mean times of interval between initial tumor prosthesis reconstruction and temporary EF apply was 8.8 years (range 3-14). One patient had EF for 150 days with 7.2 cm lengthening. Others 5 cases of 4 patients had EF for mean 37 days (range 25-50) and mean soft tissue lengthening was 5.8 cm. Three patients underwent re-insertion of tumor prosthesis and two patients underwent knee fusion as final operation and showed no evidence of infection through mean 22 months follow up period. Conclusion: Temporary using of extendible EF is an effective method for correction of leg shortening which occurred by soft tissue contracture in the complications of limb salvage operation or their treatment process, and it could be provide easily application of tumor prosthesis and knee fusion as final operation.

• The Journal of the Korean bone and joint tumor society
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• v.20 no.1
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• pp.7-13
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• 2014

Purpose: As well as patient survival, the restoration of postoperative function such as ambulation is important in limb salvage operations for treatment of malignant bone tumors involving the proximal femur. The authors analyzed clinical outcomes of limb salvage operations using tumor prostheses for metastatic or primary malignant bone tumors in the proximal femur. Materials and Methods: From February 2005 to January 2014, 20 cases (19 patients) with malignant bone tumor involving the proximal femur with pain or complicated pathologic fracture were treated with segmental resection and limb salvage operations with tumor prostheses. Mean age was 63.1 years (range 35-86). Fourteen patients were male and six ones were female. The mean follow-up period was 20 months (1-94 months). There were 15 cases of metastatic bone tumor, 4 cases of osteosarcoma, and 1 case of multiple myeloma. The primary tumors of the metastatic bone tumors included 4 lung cancers, 3 hepatocellular carcinomas, and 3 renal cell carcinomas. Other primary tumors were breast cancer, thyroid cancer, colon cancer, prostate cancer, and malignant spindle cell tumor, each in 1 case. Modular tumor prostheses were used in all cases; (Kotz's$^{(R)}$ Modular Tumor prosthesis (Howmedica, Rutherford, New Jersey) in 3 cases, MUTARS$^{(R)}$ proximal femur system (Implantcast, Munster, Germany) in 17 cases). Perioperative pain was assessed with Visual Analogue Scales (VAS). Postoperative functional outcome was assessed with Musculoskeletal Tumor Society (MSTS) grading system. Results: Out of 20 cases (19 patients), 11 cases (10 patients) survived at the last follow-up. Average postoperative survival of the 9 deceased patients was 10.1 months (1-38 months). VAS score improved from pre-operative average of 8.40 (5-10) to 1.35 (0-3) after operation. Average postoperative MSTS function score was 19.65 (65.50%, 7-28). The associated complications were 2 local recurrences, 3 hematomas, 3 infections, 2 scrotal swellings, and 1 dislocation. There was no case of periprosthetic fracture or loosening. Conclusion: Limb salvage operation with tumor prosthesis is an appropriate treatment for early pain reduction and functional restoration in malignant bone tumors in the proximal femur with pain an/or complicated pathologic fractures.

• The Journal of the Korean bone and joint tumor society
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• v.17 no.1
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• pp.36-43
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• 2011

Purpose: This study was designed to verify intermediate-term functional and radiological results of limb salvage operation using endoprosthetic replacement system ($MUTARS^{(R)}$) used in patients with a malignant bone tumor. Materials and Methods: Thirty one cases which used $MUTARS^{(R)}$ tumor prosthesis were reviewed. The mean age of the patients was 49.2 years and the mean follow up was 39.8 months. We retrospectively reviewed complications, and evaluated functionally and radiologically by Enneking functional score, ISOLS radiological implants evaluation system at last follow-up. Results: 3 patients had died of disease, distant metastasis was seen in 4 patients and local recurrence was seen in 1 patients. Complications were developed in 12 patients. (infection 6, leg length discrepancy 2, aseptic loosening 2, periprosthetic femoral fracture 1, screw loosening 1) Mean value of total functional scores were 81.2% in proximal femur, 77.4% in distal femur, 78.1% in proximal tibia, and 80.2% in proximal humerus. The overall radiological result was relatively satisfactory. Conclusion: Our results suggest limb salvage with the $MUTARS^{(R)}$ endoprosthesis is successful with good functional and radiological results. But we should be careful with complications such as infection.