Y. Iwamoto

COMPARISON OF POSTOPERATIVE EARLY ACTIVE MOBILIZATION AND IMMOBILIZATION IN VIVO UTILISING A FOUR-STRAND FLEXOR TENDON REPAIR

We evaluated a technique of four-strand double-modified locking Kessler flexor tendon repair in healing tendons. Seventy-two canine flexor digitorum profundus tendons in Zone 2 were repaired and evaluated following either active mobilization or immobilization at 0, 7, 14, 28 and 42 days after surgery. Fifty-six tendons were examined for gap and ultimate strength using a tensile testing machine and 16 were evaluated with standard hematoxylin and eosin, and Masson’s trichrome staining. All tendons healed without rupture or gap formation of more than 1 mm, thus demonstrating that this repair technique has enough tensile strength to withstand early active mobilization. The gap and ultimate strength of actively mobilized tendons did not decrease significantly during the first 7 days, and were significantly greater than those of immobilized tendons throughout the 42-day study period. Actively mobilized tendons healed without the extrinsic adhesions and large tendon calluses that were found in immobilized tendons.

The mechanical properties of locking and grasping suture loop configurations in four-strand core suture techniques

We have compared the effect of locking and grasping suture loop configurations in four-strand core suture techniques for tendon repair. Forty canine flexor digitorum profundus tendons were repaired with one of four suture techniques (the grasping cruciate, the double-modified grasping Kessler, the locking cruciate and the double-modified locking Kessler) and tested to failure in a tensile testing machine. The mode of failure in all the locking suture specimens was breakage of the sutures in the locking loops or at suture knots. The sutures did not pull out of the tendon, as was seen in the grasping suture specimens. The greatest tensile strength was found with the double-modified locking Kessler technique which incorporated eight rectangular locking loop configurations.

COMPARISON OF MECHANICAL PROPERTIES OF POLYVINYLIDENE FLUORIDE AND POLYPROPYLENE MONOFILAMENT SUTURES USED FOR FLEXOR TENDON REPAIR

We performed an experimental study to evaluate the mechanical properties of polyvinylidene fluoride sutures and to compare their use with that of standard polypropylene sutures for the circumferential, epitendinous suture of a flexor tendon repair. Polyvinylidene fluoride sutures had a smaller suture diameter, a greater knot pull strength and less delayed extension when under creep testing, than polypropylene sutures. Tendons repaired using polyvinylidene fluoride sutures had significantly greater gap and breaking strengths than those repaired using polypropylene sutures.

Comparison of the mechanical properties of polyglycolide-trimethylene carbonate (Maxon) and polydioxanone sutures (PDS2) used for flexor tendon repair and active mobilization

Thirty-six canine flexor digitorum profundus tendons were repaired using 5-0 polyglycolide-trimethylene carbonate monofilament (Maxon) or polydioxanone monofilament (PDS2). All the tendons healed without rupture or formation of gaps of more than 2 mm. Mechanically, all tendon repairs had sufficient tensile strength to enable active mobilization. Polyglycolide-trimethylene carbonate (Maxon) repairs were initially superior in gap and ultimate strength to polydioxanone (PDS2) repairs. However, the gap and ultimate tensile strength of polyglycolide-trimethylene carbonate (Maxon) repairs had decreased significantly at day 14, whereas polydioxanone (PDS2) repairs maintained their strength throughout the 28-day observation period.

Asymmetric six-strand core sutures enhance tendon fatigue strength and the optimal asymmetry

Under cyclic loading, we recorded the fatigue strength of a six-strand tendon repair with different symmetry in the lengths of suture purchase in two stumps of 120 dental rolls and in 30 porcine tendons. First, the strengths of the repairs with 1, 2, 3, 4 and 5 mm asymmetry were screened using the dental rolls. The asymmetric core suture repairs were then made with a Kessler repair of equal suture purchase (10 mm) in two tendon stumps, and shifting two other Kessler repairs by 1, 3 or 5 mm, respectively, along the longitudinal axis of the tendon in relation to the first (symmetric) Kessler repair. The core repairs with 3 mm or more asymmetry in suture purchases in two tendon ends showed significantly greater fatigue strength and significantly smaller gaps compared with 1 mm asymmetry in core suture repair. Our results support that asymmetric placement of core sutures in two tendon ends favour resisting gapping at the repair site and 3 mm or more asymmetry is needed to produce such beneficial effects.

Lipoma causing posterior interosseous nerve palsy or superficial radial nerve paraesthesia

Dear Sir, A lipoma is a benign slow-growing tumour that is usually subcutaneous. A deep lipoma at the elbow may cause compression of the posterior interosseous nerve, leading to weakness of extension of digits, and/or compression of the superficial division of the radial nerve, leading to paraesthesia (Bieber et al., 1986; Fitzgerald et al., 2002; Lidor et al., 1992). We report eight patients who had a lipoma at the elbow, two male and six female, with a mean age of 54.6 years (range, 26 to 75 years). Three patients had palsy, one of which was accompanied by paraesthesia in the radial half of the dorsum of the hand. Four patients had paraesthesia without palsy. The mean duration of symptoms to surgery was 12.7 (range, 1 to 24) months. One case had no neurological symptoms. All had surgery through an anterior approach. The compression of the posterior interosseous nerve and the superficial division of the radial nerve were recorded. Two of three cases with palsy recovered. Muscle strength was measured as described by the Medical Research Council (MRC) using the numeral grades 0–5 (Medical Research Council, 1976). One showed recovery from grade 3 (fair) to grade 5 (normal), and the other from grade 2 (poor) to 4 (good). The patient with complete paralysis showed no recovery after surgery. In all three patients with paralysis, the posterior interosseous nerve was compressed toward the flexor side (Fig 1). In the other five cases without palsy, the posterior interosseous nerve was compressed toward the flexor side in one and toward the extensor side in four. In the five patients with paraesthesia, the superficial division of the radial nerve was compressed toward the flexor side in four and toward the extensor side in one. In the other three patients without paraesthesia, the superficial division of the radial nerve was compressed toward the flexor side in one but was not compressed in two. The posterior interosseous nerve passes through the supinator muscle under the arcade of Frohse. When a tumour is located on the extensor side of the posterior interosseous nerve, it would compress it against the edge of the arcade. The superficial division of the radial nerve passes above the supinator muscle and the arcade of Frohse and is compressed by the mass itself.

Brodie’s Abscess of the Radius in a Child

We herein report an unusual case of Brodies abscess of the radius in a child. A 13-year-old boy presented with pain on his right distal forearm. A plain radiograph showed an 8 cm translucent lesion in the distal radius. MRI showed a penumbra sign on the T1-weighted image, hyperintensity on T2-weighted images, and ring enhancement on the contrast-enhanced T1 image. 18F-FDG PET/CT images showed an uptake at the margin of the radius. Curettage and iliac cancellous bone grafting were undertaken for Brodies abscess. Bacteriological examinations were found to be negative, however, the pathologic diagnosis showed chronic osteomyelitis. Eight months after surgery, the patient was asymptomatic and there was no sign of recurrence of infection. For Brodies abscess in a child, thorough debridement is mandatory in addition to cancellous bone grafting. Brodies abscess should be considered in the differential diagnosis of a patient who presents with forearm pain and exhibit the radiolucent osteolytic lesion on simple radiography.

Symmetric Peripheral Running Sutures are Superior to Asymmetric Peripheral Running Sutures for Increasing the Tendon Strength in Flexor Tendon Repair

BACKGROUND The fatigue strength of three peripheral suture techniques for flexor tendon repair was compared by cyclic loading of the repairs in the porcine flexor digitorum tendon. METHODS Thirty-six tendons were sutured using only peripheral sutures with 6-0 Nylon. An initial cyclic load of 10 N for 500 cycles was applied and increased by 10 N for an additional 500 cycles at each new load until rupture. RESULTS The fatigue strength of the symmetric running peripheral suture was 85.0% and 144.8% greater than that of the two kinds of the asymmetric running peripheral sutures. CONCLUSIONS Symmetric running sutures can enhance the suture strength and appears to be a useful technique for increasing the strength of the peripheral suture.