Comparison of three definitions of the mid-stance and mid-swing events of the gait cycle in children.

PURPOSE: Different criteria are used to define the terms mid-stance (MST) and mid-swing (MSW) when describing the gait cycle. None of these definitions is universally accepted. This causes difficulties with the interpretation of gait analysis data and hinders the comparison between the different studies. The aim of the present study was to compare three definitions of MST and MSW by examining the gait of a group of healthy children. METHOD: A prospective comparison of three commonly used definitions of the MST and MSW events of the gait cycle. OUTCOME MEASURES: The timing of the temporal, kinematic and kinetic MST and MSW of the gait cycle. RESULTS: Thirty healthy 8 - 10-year-old children were studied. There was no consistent correlation between the timing of the chosen definitions of MST and MSW. However, there was a tendency for the timing of the temporal and kinetic MST and MSW to occur, respectively, at approximately 30 and 80% of the gait cycle. CONCLUSIONS: The temporal definition of MST and MSW as the midpoints in time of the respective phases of the gait cycle appears to be more appropriate than other definitions. The use of this definition may prevent misunderstanding and permit comparison of the results of the different gait analysis studies.

Wedged tibial components for total knee arthroplasty.

Severe coronal deformity of the knee is frequently associated with erosion of one tibial condyle. This can cause problems with fixation and alignment during total knee arthroplasty. If the tibia is cut to the level of the more worn side, valuable bone is sacrificed; if the less worn side is chosen, the deficiency must be filled with bone--graft, cement, or a prosthesis. Tibial components with an integral polyethylene wedge on the undersurface were introduced in 1980 for use in patients with a bony deficit on one tibial condyle. The authors believe that the Denham prosthesis (Biomet, Wales, U.K.) was the first knee arthroplasty to offer such spacers. Twenty-six patients with preoperative varus deformity in whom a wedged component was used were compared with 29 historic control subjects. None of the wedged components loosened after a median follow-up period of 8 years compared with loosening in five of the control subjects (P = .01). In three of the control subjects a fractured triangle of cement was present on the radiographs. Use of the wedges was not accompanied by an improvement in postoperative alignment. The authors conclude that the wedges resulted in improved fixation that was independent of postoperative alignment.

Waterbike injuries.

Jet skiing is a rapidly growing sport. The craft incorporate safety features and the manufacturers issue detailed safety instructions. Racing is conducted with adequate attention to clothing, safety and insurance. However, casual use is widespread and is sometimes irresponsible. Serious injuries to riders are uncommon: dental and knee injuries are described. A case of renal contusion and a head injury were caused by other riders and two potentially fatal injuries illustrate the risk for other water users. The number of injuries associated with the use of personal watercraft is likely to increase and may be influenced by appropriate organization or regulation.

Coronal alignment after total knee replacement.

Maquet's line passes from the centre of the femoral head to the centre of the body of the talus. The distance of this line from the centre of the knee on a long-leg radiograph provides the most accurate measure of coronal alignment. Malalignment causes abnormal forces which may lead to loosening after knee replacement. We report a series of 115 Denham knee replacements performed between 1976 and 1981 using the earliest design of components, inserted with intramedullary guide rods. Patients were assessed clinically and long-leg standing radiographs were taken before operation, soon after surgery and up to 12 years later. In two-thirds of the knees (68%) Maquet's line passed through the middle third of the prosthesis on postoperative films and the incidence of subsequent loosening was 3%. When Maquet's line was medial or lateral to this, an error of approximately +/- 3 degrees, the incidence of loosening at a median period of eight years was 24%. This difference is highly significant (p = 0.001). Accurate coronal alignment appears to be an important factor in prevention of loosening. Means of improving the accuracy of alignment and of measuring it on long-leg radiographs are discussed.

Injuries of the lateral humeral condyle in children.

Thirty-seven children were admitted to the Royal Hospital for Sick Children, Edinburgh, between 1972 and 1985 with a fracture of the lateral condyle of the humerus. Twenty-four patients were reviewed between 2 and 15 years after injury. Early restriction of extension improved with time. Four patients had 2-7 degrees cubitus varus and one had exaggerated valgus. Functional results were good, but two patients exhibited crepitus or stiffness. The results of Kirschner wire fixation in this series were no better than those of soft tissue suture or of undisplaced fractures treated conservatively in a collar and cuff.

One-stage repair of hypospadias using split preputial flaps (Harris). The first 100 patients treated.

An analysis is presented of the outcome in the first 100 patients treated by a new technique for the repair of hypospadias and congenital short urethra associated with chordee. Further reconstructive surgery was required in 24 patients. The effect of the position of the meatus, the length of the reconstructed urethra and the method of urinary drainage are analysed. Minor complications are described. A significantly higher complication rate was associated with a perurethral than with a suprapubic catheter; 5 of the 38 patients in whom a suprapubic catheter was used developed complications requiring reconstructive surgery. Possible causes of the complications are discussed and the results compared with those of other methods. It was concluded that this is a satisfactory method of repair for hypospadias associated with chordee.