Effect of bone density on the drill-hole diameter made by a cannulated drill bit in cancellous bone.

BACKGROUND: When a pilot hole is made prior to a screw's insertion into bone, the same drill bit is used irrespective of the bone quality. However, osteoporotic bone is fragile and this may affect the hole diameter, which is of particular concern in cancellous bone. In this study, the relationship between bone density and drill-hole diameter was investigated assuming a pre-drilling process in screw-only osteosynthesis in the metaphysis and epiphysis. METHODS: Two types of drill bit (triple-flute [T] and quadruple-flute [Q]) with different shapes and diameters were prepared: type T bits with 3.5 mm and 4.4 mm diameters, and type Q bits with 3.5 mm and 4.2 mm diameters. Drilling was performed manually in simulated bones with four densities: 5, 10, 15, and 20 pounds per cubic foot. We measured the hole diameters with a coordinate measuring machine and analyzed the relationship between the drill-hole diameters and the densities of the simulated bones. We then compared the screw pull-out strength between the two 3.5-diameter drill bits. RESULTS: In all cases, the diameters of the drill holes were larger than those of the drill bits. The relationship between the drill-hole diameters and the bone densities was a negative linear correlation. Enlarging the hole diameter decreased the screw pull-out strength. CONCLUSIONS: For cannulated drill bits of 3.5, 4.2 and 4.4 mm diameter, the diameter of the drill hole in cancellous bone obtained by the manual drilling technique tends to be larger in low-density (e.g., osteoporotic) compared to high-density (e.g., healthy) bone.

The clinical outcomes of scaphoid nonunion treated with a precisely processed autologous bone screw: a case series.

INTRODUCTION: Metal implants and bioabsorbable implants are frequently used in orthopaedic surgery, but they have some disadvantages. The usefulness of autologous bone has been described, and a method to precisely process autologous bone into implants such as screws and apply the implants clinically has been desired. We created a new system for manufacturing autologous bone screws during surgery and report five cases of scaphoid nonunion treated with precise autologous bone screws made from the tibial cortex using the new system. PATIENTS AND METHODS: From 2012 through 2017, seven patients were diagnosed with scaphoid nonunion at our hospital and based on the inclusion/exclusion criteria, five of them were analyzed herein. The surgery was performed according to Zaidemberg's technique. The bone screw in each case was made from autologous tibial cortex using a numerically controlled lathe (model MTS4, Nano Co., Yokohama, Japan) under sterile conditions. The change in each patient's modified Mayo wrist score between the preoperative examination and at the final survey was determined, as were complications. RESULTS: The median modified Mayo wrist score improved significantly from 65 to 95 points. All patients who were followed for > 2 years fused at a median duration of 3.5 months. Bone regeneration was confirmed at the donor sites in all cases. One fracture at the donor site occurred as a severe complication. CONCLUSIONS: Precisely shaped autologous bone screws manufactured by a computer-assisted machine, together with a vascularized bone graft, may be a useful technique for treating scaphoid nonunions; these screws had good stability and bone replacement. Careful observation of the donor site is required. LEVEL OF EVIDENCE: IV.

Relationship between thread depth and fixation strength in cancellous bone screw.

BACKGROUND: Clarifying the effect of each parameter of screw design on its fixation strength is critical in the development of any type of screw. The purpose of this study was to clarify the relationship between the thread depth and fixation strength of metal screws for cancellous bone. METHODS: Nine types of custom-made screws with the only changed variable being the thread depth were manufactured. Other elements were fixed at a major diameter of 4.5 mm, a thread region length of 15 mm, a pitch of 1.6 mm, and a thread width of 0.20 mm. The pull-out strength and insertion torque of each screw were measured for each of two foam-block densities (10 or 20 pcf). The correlation between the thread depth of the screw and the mechanical findings were investigated with single regression analysis. RESULTS: Regardless of the foam-block density, the pull-out strength significantly increased as the thread depth increased from 0.1 mm to 0.4 mm; after that, the increase was more gradual (p < 0.01, respectively). The relationship between the thread depth and insertion torque was similar. In addition, the insertion torque tended to be more strongly affected by screw depth than the pull-out strength (2.6 times at 20 pcf and 1.4 times at 10 pcf). CONCLUSIONS: The pull-out strength of 4.5-mm-diameter metal screws in a cancellous bone model was found to be biphasic, although linearly correlated with the change in screw depth in both phases. The boundary of the correlation was 0.4 mm regardless of the density of the bone model, with the effect of screw depth on pull-out strength beyond that being small in comparison.

Effect of the positional relationship between the interference screw and the tendon graft in the bone tunnel in ligament reconstruction.

PURPOSE: To reveal the effects of the positional and length relationships between the interference screws (ISs) and the tendon graft in the bone tunnel on the fixation strength in ligament reconstruction. METHODS: We compared three IS positions on the anterior (the Anterior group) or posterior (the Posterior group) or side (the Side group) of the tendon graft in relation to the pullout direction. The tendon graft was pulled at 0°, 30°, 60°, and 90° to the bone tunnel, and the maximum pullout load at each angle was compared among the groups. We also investigated the relationship between the length of the tendon graft and the length of the IS in the bone tunnel. The direction of the pullout force was the same as that of the Anterior group, and the maximum load was compared between groups in which the tendon graft was longer or shorter than the IS. RESULTS: The maximum loads of the Anterior group were significantly greater than those of the Posterior and Side groups at the traction angles of 30° and 60°, respectively. An IS shorter than the tendon graft was found to provide significantly superior fixation strength compared to an IS longer than the tendon graft. CONCLUSIONS: Better fixation strength was achieved when the IS was placed on the side of the anchorage tunnel on which the tendon graft was loaded and the IS was shorter than the tendon graft.

Atraumatic Spontaneous Achilles Tendon Rupture in Patients Receiving Oral Corticosteroids Treated With the Modified Side-Locking Loop Suture Technique.

Atraumatic spontaneous Achilles tendon ruptures sometimes occur in patients receiving oral corticosteroids. In general, these cases are treated surgically; however, delayed postoperative management can lead to impaired activities of daily living. The modified side-locking loop suture (SLLS) technique is a useful suture method for safe and early active mobilization. Three cases of spontaneous Achilles tendon ruptures were treated with the modified SLLS technique with good clinical results. The modified SLLS technique is a useful method with a short rehabilitation period for treating atraumatic spontaneous Achilles tendon rupture in patients undergoing corticosteroid therapy.

Osteomyelitis of the accessory and body of the navicular bone: a case report.

A 16-year-old boy developed left foot pain of unknown cause that was unresponsive to conservative treatment, associated with fever and difficulty walking. He was admitted to our hospital with osteomyelitis of the accessory and body of the navicular bone. Surgery could not be performed because the patient had been diagnosed with Wiskott-Aldrich syndrome. After antibiotic therapy, laboratory abnormalities and pain had resolved. One year after treatment, the patient had returned to his original level of sports activity. Both an accessory navicular and the body of the navicular bone may develop osteomyelitis in immunocompromised patients; early diagnosis is important for prescribing effective conservative treatment.

Acute Achilles Tendon Rupture Treated by Double Side-Locking Loop Suture Technique With Early Rehabilitation.

BACKGROUND: Although early accelerated rehabilitation is recommended for the treatment of acute Achilles tendon rupture, most traditional rehabilitation techniques require some type of brace. METHODS: We retrospectively analyzed 44 feet of 44 patients (25 male and 19 female) with a mean age of 31.8 years who had an acute Achilles tendon rupture related to athletic activity. Patients had been treated by a double side-locking loop suture (SLLS) technique using double antislip knots between stumps and had undergone early accelerated rehabilitation, including active and passive range of motion exercises on the day following the operation and full weight-bearing at 4 weeks. No brace was applied postoperatively. The evaluation criteria included the American Orthopaedic Foot & Ankle Society Ankle-Hindfoot Scale (AOFAS) score; active plantar flexion and dorsiflexion angles; and the intervals between surgery and the time when patients could walk normally without any support, perform double-leg heel raises, and perform 20 continuous single-leg heel raises of the operated foot. RESULTS: Despite postoperative early accelerated rehabilitation, the AOFAS score and active dorsiflexion angles improved over time (6, 12, and 24 weeks and 2 years). A mean of 4.3 ± 0.6 weeks was required for patients to be able to walk normally without any support. The mean period to perform double-leg heel raises and 20 continuous single-leg heel raises of the injured foot was 8.0 ± 1.3 weeks and 10.9 ± 2.1 weeks, respectively. All patients, except one who was engaged in classical ballet, could return to their preinjury level of athletic activities, and the interval between operation and return to athletic activities was 17.1 ± 3.7 weeks. CONCLUSION: The double SLLS technique with double antislip knots between stumps adjusted the tension of the sutured Achilles tendon at the ideal ankle position and provided good clinical outcomes following accelerated rehabilitation after surgery without the use of a brace. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Clinical outcomes of revision meniscal repair: a case series.

BACKGROUND: Meniscal preservation results in better clinical outcomes than meniscectomy; however, no studies have evaluated the results of revision meniscal repair. HYPOTHESIS: Revision meniscal repair can achieve good clinical outcomes. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The study participants were 16 patients with symptomatic meniscal retears of a total of 96 patients who underwent primary arthroscopic meniscal repair. Fifteen of these 16 patients underwent revision meniscal repair. The mean age at revision was 27 years, and the mean duration between the primary operation and revision was 27 months. Eight patients had degenerative changes of the meniscus at revision. Clinical outcomes were assessed using the Lysholm score and the Tegner sports activity score, and image assessment was performed using magnetic resonance imaging. RESULTS: Five patients had re-retears of a resutured meniscus, and the mean duration between revision and the re-retear was 25 months (range, 8-68 months). The mean follow-up of patients without re-retears was 41 months (range, 24-74 months), and the mean Lysholm score in those without re-retears significantly improved from 81.4 points (range, 73-89 points) at pre-revision to 97.4 points (range, 90-100 points) at the final survey (P = .0001). Degenerative changes of the meniscus at the revision site were observed in all 5 patients with re-retears but in only 3 of the 10 patients without re-retears. CONCLUSION: Revision meniscal repair should be considered in the setting of a retorn meniscus without degenerative changes.

Modification of side-locking loop suture technique using an antislip knot for repair of Achilles tendon rupture.

The 2-strand side-locking loop suture technique provides high tensile strength and stiffness immediately after surgery, and good clinical results have been reported in the treatment of Achilles tendon rupture. However, it is assumed that major differences exist among surgeons with regard to the optimal tension of the side-locking loop suture. We report a detailed technique to ensure application of a standard tension with the use of the side-locking loop suture in the clinical setting.

A comparison of patient-reported outcomes and arthroscopic findings between drilling and autologous osteochondral grafting for the treatment of articular cartilage defects combined with anterior cruciate ligament injury.

BACKGROUND: To compare the patient-reported outcomes and arthroscopic findings between drilling and autologous osteochondral grafting (AOG) for the treatment of articular cartilage defects combined with anterior cruciate ligament (ACL) injuries. METHODS: The subjects were 40 patients who had articular cartilage defects in the weight-bearing part of the medial and lateral femur condyle combined with ACL injuries that were treated by drilling (20 patients) or AOG (20 patients) at the same time as ACL reconstruction was performed. In the drilling group patients, lesions were penetrated with multiple 1.2-mm Kirschner wires, and in the AOG group patients, grafts were made to cartilage defects from one to three osteochondral pegs harvested from the less-weight-bearing periphery of the articular surface of the femoral condyle. The patient-reported outcomes were assessed using the International Knee Documentation Committee (IKDC) subjective knee examination score. Second-look arthroscopy was performed to evaluate the repaired cartilage macroscopically. RESULTS: The median follow-up duration was 25 (range, 12-42) months. The IKDC scores were significantly improved from 64.4 to 95.4 points in the drilling group and from 52.3 to 94.3 points in the AOG group, with no difference between the two groups, although there was a difference in the repaired cartilage findings of arthroscopy. CONCLUSION: In this study, no differences in IKDC scores were found in patients with a concomitant ACL rupture and an osteochondral lesion treated by drilling or AOG at a minimum follow-up of 1year, regardless of the differences at arthroscopic grading of the ICRS classification. LEVEL OF EVIDENCE: Case-control study (LEVEL III).

Superior fixation of machine-made bone pegs over handmade bone pegs.

BACKGROUND: Bone pegs are one of the best devices to treat an intra-articular lesion with fragments because of the pegs' biological characteristics, but the initial strength of the fragment fixation in these cases is unknown. In addition, the relationship between the geometry of bone pegs and the strength of fragment fixation remains unknown. We hypothesized that a microscopically fine bone peg made by a precision machine can provide a higher level of strength than that of a macroscopically fine bone peg made by hand both initially and postoperatively. METHODS: The machine-made bone pegs were made from cortical bone of cattle by a precision machine, and the handmade bone pegs were made by hand using the same material. An osteochondral lesion model was made, and two pegs of the same type were inserted to fix each test fragment. The shearing and pull-out strength of the fragment were investigated in both types of peg. Next, both types of peg were inserted into a hole made in the distal femur of a rabbit, and 10 days later, mechanical tests were performed. RESULTS: The machine-made bone pegs were initially twice as strong as the handmade bone pegs, and they were 1.4 times as strong as the handmade bone pegs at 10 days after surgery. CONCLUSION: We recommend that bone pegs be made by machining rather than by hand. The machine-made bone pegs have the potential to ensure early postoperative rehabilitation.

Mid-term outcome of talocalcaneal coalition treated with interposition of a pedicle fatty flap after resection.

BACKGROUND: We have previously reported a new technique to treat symptomatic talocalcaneal coalition. The purpose of the present study was to evaluate the mid-term outcome of the interposition of a pedicle fatty flap after the resection of a talocalcaneal coalition. METHODS: Six feet of 5 patients with persistently symptomatic talocalcaneal coalition were treated with this method. We investigated the clinical outcome using the visual analog scale (VAS) for hindfoot pain including around coalition and the American Orthopaedic Foot and Ankle Society (AOFAS) score pre- and postoperatively, and investigated whether or not recurrence was present using computed tomography (CT) at the final followup. RESULTS: The VAS score was significantly improved from 5.5 +/- 1.0 (mean +/- SD) to 9.7 +/- 0.5 points (p = 0.0006). The AOFAS hindfoot score was also improved significantly (from 73.3 +/- 26.7 points to 96.7 +/- 7.1 points). No recurrence was detected by CT at the final followup. CONCLUSION: The interposition of a pedicle fatty flap after resection has been a durable procedure for treating a symptomatic talocalcaneal coalition.

Effectiveness and limitations of autologous osteochondral grafting for the treatment of articular cartilage defects in the knee.

PURPOSE: To evaluate the effectiveness and limitations of autologous osteochondral grafting for the treatment of articular cartilage defects in the knee. METHODS: The subjects were 40 patients who had undergone autologous osteochondral grafting. Fifteen knees had cartilage defects combined with anterior cruciate ligament tears (ACL group), 15 knees had cartilage defects combined with osteoarthritis (OA group), and 10 knees had cartilage defects combined with osteochondral dissecans (OCD group). From one to five osteochondral pegs were harvested from the less-weight-bearing periphery of the articular surface of the femoral condyle and grafted to cartilage defects. The clinical results were assessed based on the Lysholm score and radiographic and magnetic resonance imaging (MRI) image assessment. RESULTS: The median follow-up duration was 24 months (range from 12 to 41 months). The mean Lysholm score following treatment was improved in all groups. The patients who had cartilage defects combined with OA had a significantly poorer prognosis than did those with cartilage defects combined with ACL or OCD. In the OA group, advanced stage and an alignment abnormality were correlated with poor prognosis. Advanced age was correlated with poor prognosis. Other parameters showed no significant difference in prognosis. CONCLUSION: Autologous osteochondral grafting was found to be an effective technique for treating relatively young patients who had cartilage defects combined with ACL injury or OCD, but this technique showed limited results in treating cartilage defects based on advanced patient age and degenerative changes in the cartilage. LEVEL OF EVIDENCE: Diagnostic studies-investigating a diagnostic test, Level III.

Sequential multiple insufficiency fractures around knee over 6 months in a patient with primary osteoporosis.

In this report, we describe a case of multiple insufficiency fractures occurring over 6 months in the bilateral knees of an individual with primary osteoporosis. An 87-year-old woman complained of spontaneous pain in her right knee. A plain X-ray did not show any lesions at the time; however, 2 weeks later, a slightly displaced supracondylar fracture was observed. The fracture was treated with a long leg cast for 6 weeks. The patient was able to walk with a walker 12 weeks after the injury, but her right thigh muscles had atrophied. Four months after the first injury, she suffered left knee pain. Magnetic resonance imaging (MRI) showed an undisplaced supracondylar fracture of the left femur. After undergoing the same treatment as for the previous fracture for 8 weeks, she complained of pain in the proximal tibia, and a fracture in the lateral tibial plateau was observed by MRI. No malignancy or endocrine disorders were found by imaging or laboratory studies. Her bone mineral density was found to be low, and she was diagnosed with multiple insufficiency fractures due to primary osteoporosis. The work overload on the healthy side induced by muscle weakness on the affected side may have caused the subsequent insufficiency fractures on the healthy side. These findings suggest that one should pay attention to and treat lower limb muscle atrophy when managing insufficiency fractures of the lower limbs.

Effectiveness and biocompatibility of a novel biological adhesive application for repair of meniscal tear on the avascular zone.

We have investigated the effectiveness and safety of a newly developed biological adhesive for repair of meniscal tear. The adhesive was composed of disuccinimidyl tartrate (DST) as a crosslinker and human serum albumin (HSA) as a hardener. To determine adequate concentration, bonding strength was measured using a tensiometer 5 min after applying the adhesive on the avascular zone tear of porcine meniscus; it was compared with the strengths of commercially available cyanoacrylate-based and fibrin-based adhesives. In vivo examination was performed using Japanese white rabbits, creating longitudinal tears on the avascular zone of meniscus and applying DST-HSA adhesive. Three months after operation the rabbits were sacrificed and tension test and histological evaluation were performed. Bonding strength was measured in three porcine meniscus groups: (i) only suturing, (ii) suturing after applying the adhesive on surface and (iii) suturing using an adhesive-soaked suture. The optimum concentrations were 0.1 mmol of DST and 42 w/v% of HAS. Bonding strength was greatest with cyanoacrylate-based adhesive, followed by DST-HSA adhesive, and fibrin-based adhesive. No inflammation was observed in the synovium or surrounding tissues 3 months after using the DST-HSA adhesive. Bonding strength was greatest with DST-HSA adhesive-soaked suturing group (77 ± 6 N), followed by suturing only group (61 ± 5 N) and surface adhesive application group (60 ± 8 N). The newly developed DST-HSA adhesive is considered safe and may be effective in enforcement of bonding of avascular zone tear of the meniscus.