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.

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.

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.

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.

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.

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.

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.

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.

Nonunion in proximal phalanx of great toe treated by grafting with precisely processed autologous bone PEG.

We report a rare case of nonunion in the proximal phalanx of the great toe treated by grafting with a precisely processed autologous bone peg. The concept of this surgical method was to fix the nonunion of the proximal phalanx of the great toe using press-fit fixation and a bone peg precisely formed to fit the medullary cavity similar to an intramedullary nail. We believe that our new technique is a viable alternative for the treatment of phalanx fractures or nonunions requiring bone grafts.

Leg anterior compartment syndrome following ankle arthroscopy after Maisonneuve fracture.

We report a case of leg anterior compartment syndrome following ankle arthroscopy after Maisonneuve fracture. A 21-year-old football player sprained his left ankle. Plain radiography of his left ankle showed a lateral dislocation of the talus without obvious fractures. Plain radiography of his left lower extremity showed a spiral fracture of the proximal fibula approximately one third distal to the fibular head. According to these findings, we diagnosed this fracture as a Maisonneuve fracture and treated it by ankle arthroscopy and drilling of the talar osteochondral injury followed by arthroscopic ankle visualization during syndesmosis screw fixation. Six hours after surgery, the patient complained of pain in the lower extremity. We diagnosed acute compartment syndrome and performed emergent fasciotomy. One year after surgery, he was able to fully participate in athletic activities. We consider ankle arthroscopy to be available for the treatment of ankle fracture with the suspected complication of an intra-articular disorder such as a Maisonneuve fracture. However, with this type of ankle fracture, there is a higher potential risk of acute compartment syndrome developing than with other types of ankle fractures. Therefore we suggest that surgeons guard against this complication.

Effect of implant surface roughness on bone fixation: the differences between bone and metal pegs.

BACKGROUND: Pegs made from cortical bone are used to fix osteochondral fractures and osteochondral dissecans. This technique has many advantages, but it requires long-term immobilization. This study examined the effect of surface roughness on fixation with bone and metal pegs. METHODS: Pegs with either rough or smooth surfaces were made of cortical bone from Japanese black cattle or from stainless steel (SUS316L). The mean roughness of the rough surface was 15.0 microm, whereas that of the smooth surface was less than 0.6 microm. Pegs were inserted into holes made in the distal femurs of 34 rabbits. At the time of surgery and 14 days later, mechanical tests and micro-computed tomography were performed. RESULTS: At the time of surgery, although the push-out forces were less than 0.3 N, the rough surface had a higher value than the smooth surface (P = 0.0002). No difference was observed according to the material (P = 0.54). Fourteen days after surgery, no significant difference was detected in the push-out forces between bone pegs with rough and smooth surfaces (489.0 +/- 149.6 vs 478.3 +/- 134.4 N (mean +/- SD), respectively), but a marked difference was seen with the metal pegs (235.7 +/- 115.7 vs 2.2 +/- 1.6 N). The bone pegs with rough surfaces made contact with the recipient bone at the high points on the abraded surfaces. After the mechanical tests, the fusion was broken within the new bone for bone pegs with rough or smooth surfaces, but no breakage occurred at the junction of bone peg and new bone. CONCLUSION: The surface roughness of bone pegs has little effect on bone-to-bone fusion 2 weeks postoperatively, unlike the effect with metal pegs.

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.

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.