Myung Ku Kim

Factors associated with clinical and structural outcomes after arthroscopic rotator cuff repair with a suture bridge technique in medium, large, and massive tears

BACKGROUND This study was conducted to evaluate clinical outcomes, maintenance of repair integrity, and retear rate after arthroscopic rotator cuff repair by a suture bridge technique among patients with medium, large, and massive rotator cuff tears. METHODS We evaluated 147 patients who had undergone arthroscopic rotator cuff repair. Clinical and functional evaluations were performed with the Constant and University of California-Los Angeles scores. All patients were confirmed to have magnetic resonance imaging evidence of tendon healing at least 12 months postoperatively. RESULTS The average postoperative time to follow-up magnetic resonance imaging was 23.4 months (range, 12-48 months). A total of 25 (17.0%) retears were observed. All clinical outcome scores were improved significantly at follow-up. Larger intraoperative tear sizes were correlated with higher retear rates. The incidence of retear was also higher in cases in which the preoperative fatty degeneration grade was higher. The incidence of retear increased with age and in the heavy worker group (e.g., farmers, carriers, car mechanics) but was not statistically significant. CONCLUSIONS Arthroscopic rotator cuff repair by a suture bridge technique yields improvements in clinical outcome measures and a relatively high degree of patient satisfaction despite the fact that repair integrity is not maintained in many cases.

Novel approaches to fracture healing

The fractures that occur as a result of trauma frequently require multiple stage surgical procedures to achieve adequate union. Bone grafting with autogenous cancellous or cortico cancellous bone grafts is the traditional method used to repair bone defects. Most fractures will heal using this traditional procedure, however a number of fractures, up to 10% of the cases in United States alone, will result in delayed or impaired healing. Novel approaches are currently being investigated for the augmentation and acceleration of fracture healing. Some of these approaches include the use of biodegradable matrices; cell based approaches supplemented with osteogenic factors and genetic therapy. Cell based approaches for fracture healing have roused intense interest because of the great advance in the isolation and expansion of cells from the marrow that have the ability to differentiate into various types of cells including osteoblasts. In addition, the discovery and cloning of several proteins (bone morphogenetic proteins) that have the ability to induce bone formation, have contributed to the investigation of novel approaches to augment fracture healing. Use of genetic therapy for the augmentation of fracture healing has also recently gained strong interest. The attractive feature of gene therapy is that therapeutic proteins can be delivered locally to the fracture site in relatively high concentrations and in a sustained fashion. This review discusses these novel approaches and presents an assessment of their future clinical applicability.

New modified technique of osteotomy for hallux valgus

Purpose. To improve the technique of osteotomy for hallux valgus (bunion). Methods. 38 cases of a new modified osteotomy procedure for hallux valgus were performed for 22 patients (21 women and one man). During a 3-year (range, 2–5 years) follow-up, the patients underwent physical examination; and their American Orthopedic Foot and Ankle Society hallux-metatarso-phalangeal-interphalangeal scale scores and standard foot radiographic measurements were recorded. Results. 20 of the 22 patients (38 cases) had no pain, achieved good cosmesis, and were completely satisfied with the results of the operation. The remaining 2 patients had occasional mild discomfort. The mean hallux-metatarso-phalangeal-interphalangeal scale score was 93 points (range, 78–100 points). The mean preoperative and postoperative metatarsophalangeal angles were 34 degrees and 11 degrees, respectively. The mean postoperative reduction of the inter-metatarsal angle and metatarsophalangeal angle were 6 degrees and 23 degrees, respectively. Conclusion. The new technique of osteotomy achieved even greater stability and accurate correction of the deformity in our 38 cases. Furthermore, it was more effective than conventional ‘chevron’ osteotomy in terms of correction of the deformity. Therefore, it should be used more widely.

Clinical and radiological results after modified distal metatarsal osteotomy for hallux valgus.

Background: The chevron osteotomy is an acceptable method for correction of mild and moderate hallux valgus, but can result in instability at the osteotomy site. The purpose of this study was to present clinical and radiological results with our modified technique of osteotomy. Materials and Methods: We performed a modified technique of distal osteotomy of the first metatarsal on 77 feet of 46 patients with symptomatic hallux valgus; followed up for an average of 52 months. Results: All of the patients experienced satisfactory pain relief and acceptable cosmesis. The mean postoperative reduction in the intermetatarsal angle was 6.5 degrees and of the metatarsophalangeal angle was 23.0 degrees. There was no loss of correction and there was no discrepancy in preoperative and postoperative lengths of the first metatarsal during the followup period. Conclusion: We found our modified distal metatarsal osteotomy to be an effective method of correcting hallux valgus.

Comparison of bioabsorbable suture anchor fixation on the tibial side for anterior cruciate ligament reconstruction using free soft tissue graft: experimental laboratory study on porcine bone.

Purpose The use of graft tissue fixation using bioabsorbable interference screws (BISs) in anterior cruciate ligament (ACL) reconstruction offers various advantages, but limited pullout strength. Therefore, additional tibial fixation is essential for aggressive rehabilitation. We hypothesized that additional graft tissue fixation using bioabsorbable suture anchors (BSA) would provide sufficient pull-out strength. Materials and Methods Twenty four fresh frozen porcine distal femur and patellar tendon preparations were used. All specimens were divided into three groups based on additional fixation methods: A, isolated BIS; B, BIS and BSA; and C, BIS and post cortical screw. Tensile testing was carried out under an axial load. Ultimate failure load and ultimate failure load after cyclic loading were recorded. Results The ultimate failure loads after load to failure testing were 166.8 N in group A, 536.4 N in group B, and 438 N in group C; meanwhile, the ultimate failure loads after load to failure testing with cyclic loading were 140 N in group A, 466.5 N in group B, and 400 N in group C. Stiffness after load to failure testing was 16.5 N/mm in group A, 33.5 N/mm in group B, and 40 N/mm in group C. An additional BSA fixation resulted in a significantly higher ultimate failure load and stiffness than isolated BIS fixation, similar to post screw fixation. Conclusion Additional fixation using a BSA provided sufficient pullout strength for ACL reconstruction. The ultimate failure load of the BSA technique was similar to that of post cortical screws.

A New Surgical Technique of Arthroscopic Partial Meniscectomy for Unstable Inferior Leaf of the Anterior Horn in a Horizontal Tear of Lateral Meniscus

We introduce a new arthroscopic partial meniscectomy technique using a three portals and a small skin hook retractor to remove unstable inferior leaf in horizontal meniscal tear that involved the anterior portion of the lateral meniscus. The patient is positioned for a standard knee arthroscopy. After careful estimation of the depth and extent of the cleft and stability of the superior and inferior leaves is done through the standard anteromedial portal, a small skin hook retractor is inserted through the standard anterolateral portal to raise the dominant superior leaf of anterior horn, then the unstable inferior leaf is excised with a 90° rotary punch and a motorized shaver through the extreme far anteromedial portal. This technique is useful method to remove unstable inferior leaf of anterior horn of lateral meniscus which is difficult to remove with a standard technique.

Clinical Characteristics of Methicillin-resistant Staphylococcus aureus Infection for Chronic Periprosthetic Hip and Knee Infection.

Purpose Deep infection after hip and knee arthroplasty is a serious complication and is difficult to treat due to its toxicity. The aims of our study were to find out the differences of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) infection after hip and knee arthroplasty focusing on clinical course and laboratory findings. Materials and Methods We retrospectively reviewed 61 staphylococcal infection cases after hip and knee arthroplasty (MSSA in 25 patients, MRSA in 36 patients). Vital signs, laboratory tests, microbiology and clinical courses were analyzed. The average follow-up period was 3.8 years (range, 2 to 10.1 years). Results At initial visit, MRSA group showed significant higher erythrocyte sedimentation rate, C-reactive protein (CRP) and neutrophil percentage. The average duration for the normalization of CRP was longer in MRSA group (MRSA: 36.7±25.1 days, MSSA: 24.7±13.6 days; P=0.008). The mean interval between staging operation was longer in MRSA group (MRSA: mean 8.7 weeks [range, 6.4 to 21.4 weeks], MSSA: mean 6.8 weeks [range, 6 to 13.1 weeks]; P=0.012). MRSA group (13.9%) revealed higher recurrence rate than MSSA group (4%). Two patients (5.6%) from MRSA group expired by sepsis. One limb amputation (2.7%) was carried out in MRSA group. Conclusion MRSA infection after arthroplasty showed more toxic serologic parameter and poorer prognosis. Aggressive treatment should be considered for MRSA infection following arthroplasty.

Modified Technique of Distal Metatarsal Osteotomy for Hallux Valgus

Osteotomy of the first metatarsal accompanied by medial eminence removal and soft-tissue reconstruction is the procedure generally performed to correct symptomatic hallux valgus, but the choice of operation is difficult and failed hallux valgus correction has been reported.3 Corless1 reported a modification of the technique described by Mitchell et al.4 in which the osteotomy was V-shaped to provide greater stability. However, the conventional chevron osteotomy is not always stable and sometimes requires internal fixation with wires or passage of a heavy suture through offset drill holes.6,7 Malunion also has been reported at the osteotomy site.5 Johnson et al.2 reported excellent relief of pain and cosmetic correction with the modified chevron osteotomy technique in 26 feet (18 patients). The modified chevron osteotomy seems to produce anatomic correction similar to that of our technique and has better stability at the osteotomy site; however, it does not prevent dorsal angulation or medial or lateral tilting or shortening. Trnka et al.5 reported intraoperative instability in four of 46 chevron osteotomies. We have further modified the technique to provide even greater stability at the osteotomy site. Our modified technique prevents dorsal angulation as well as medial and lateral tilting and shortening at the osteotomy site because of the rectangular anatomical end-to-end contact of the dorsal metatarsal cortex of the osteotomy site. For this reason, we believe that our modified technique achieves a more stable result at the osteotomy site, and a more accurate correction is possible.

Autologous Bone Marrow Cell Stimulation and Allogenic Chondrocyte Implantation for the Repair of Full-Thickness Articular Cartilage Defects in a Rabbit Model

Objective: The aim of this study was to evaluate the results of autologous bone marrow cell stimulation and allogenic chondrocyte implantation using 3-dimensional gel-type fibrin matrix in an animal model. Design: Eighteen rabbits were divided into 2 treatment groups. One group was treated with a microfracture and covering of it with gel-type fibrin (AutoBMS; n = 9), and the other group was treated with allogenic chondrocytes mixed gel-type fibrin at the cartilage defect (AlloCI; n = 9). The control group was untreated cartilage defect at the other side knee of each object. Twelve weeks after treatment, the cartilage was evaluated using the International Cartilage Repair Society (ICRS) scoring system, immunohistochemical staining, and modified O’Driscoll grading system. Results: The ICRS scores were similar in the AutoBMS (9.44 ± 2.44) and the AlloCI (9.33 ± 1.67) groups (P < 0.05). Immunohistochemical staining confirmed higher expression of cartilaginous collagen for both groups. The average difference (AutoBMS, 31.89 ± 6.54; AlloCI, 32.89 ± 5.25) in the modified O’Driscoll scores appeared to be nonsignificant (P > 0.05); however, both treatment groups showed significantly higher scores with respect to their control group (18.45 ± 1.65; 18.97 ± 1.58) (P < 0.05). Conclusion: This experimental study suggests autologous bone marrow cells stimulation and implantation of allogenic chondrocytes are both useful methodologies for regenerating hyaline-like cartilage in full-thickness cartilage defects in animal model.