Total hip arthroplasty after previous proximal femoral osteotomy.

We compared 74 total hip arthroplasties (THAs) carried out after previous proximal femoral osteotomy with a diagnosis-matched control group of 74 primary procedures performed during the same period. We report the perioperative results and the clinical and radiological outcome at five to ten years. We anticipated a higher rate of complications in the group with previous osteotomy, but found no significant difference in the rate of perioperative complications (11% each) or in the septic (8% v 3%) and aseptic (4% each) revision rates. There was a trend towards improved survival in the group without previous osteotomy (90% v 82%), but this difference was not statistically significant. The only significant differences were a higher rate of trochanteric osteotomy (88% v 14%) and a longer operating time in the osteotomy group. Our study indicates that THA after previous osteotomy is technically more demanding but not necessarily associated with a higher rate of complications. Furthermore, proximal femoral osteotomy does not jeopardize the clinical and radiological outcome of future THA enough to exclude the use of osteotomy as a therapeutic alternative in younger patients.

A quantitative in vitro assessment of fit and screw fixation on the stability of a cementless hemispherical acetabular component.

This investigation quantifies in vitro the effect of component fit, as well as the effect of adjuvant screw fixation, on the initial stability of cementless hemispherical titanium acetabular total hip arthroplasty components and assesses apposition of the acetabular components to bone. Six, fresh human hemipelvi (3 matched pairs) were harvested at autopsy. Titanium alloy acetabular components with a porous surface of commercially pure titanium fiber mesh (Harris Galante Porous acetabular components, Zimmer, Warsaw, IN) were used for implantation. Initially, each acetabulum was underreamed to achieve a 2 mm press-fit with the acetabular component. Pressure-sensitive film had been placed along the dome and medial wall at the bone-implant interface to assess the completeness of seating. After the implant was impacted into the acetabular cavity, relative motion between the implant and bone was measured during simulated single leg stance. Adjuvant fixation of the implant was then obtained with the insertion of four 6.5 mm cancellous screws. High-contrast roentgenograms of the specimens in multiple views were obtained after initial cup insertion and again after screw insertion. The stability of each implant under load was measured with four, three, two, one, and no screws in place. Further reaming of the bone was done to create a 1 mm press-fit. The sequence was then repeated. Further reaming was done to create an exact-fit and the sequence was repeated again. Under these conditions, 1 mm press-fit with or without screws provided the optimum combination of fit stability.(ABSTRACT TRUNCATED AT 250 WORDS)

The contribution of the nonporous distal stem to the stability of proximally porous-coated canine femoral components.

The contribution of the distal nonporous-coated stem to the stability of the uncemented femoral components, which were porous coated only proximally, was investigated under two conditions: (1) immediately after insertion and (2) at 6 months, 1 year, and 2 years after surgery in a canine model. The relative motion of the femoral components at the bone porous-coating interface under loads simulating the canine midstance was measured at these time periods using displacement transducers. The measurements were repeated after severing the connection between the porous-coated proximal body and the nonporous-coated distal stem through a small hole in the anterior cortex. The results showed that while the distal nonporous-coated stem enhanced the immediate stability of the proximally porous-coated uncemented femoral components, it contributed little to the long-term stability of the femoral components after bony ingrowth had occurred in vivo. The mean relative motion between the body of the prosthesis and the cortical bone increased from 12 microns (+/- 7 microns) to 31 microns (+/- 34 microns) in the posterior transverse direction when the stem was immediately severed after the surgery. However, at 6 months, 1 year, and 2 years after surgery, extensive bone ingrowth had occurred into the proximal porous-coated regions of the body and provided excellent stability to the femoral components. With bone ingrowth, the mean relative motion was less than 5 microns at any site. Under these conditions, severing the stem did not increase the relative motion of the prostheses significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Predictors of functional outcomes after arthroscopic partial meniscectomy.

OBJECTIVE: To confirm previous studies that have identified knee osteoarthritis as the principal correlate of poor outcomes after arthroscopic partial meniscectomy (APM), we considered a range of other preoperative characteristics using multivariable analyses to control for confounding variables. METHODS: One hundred five patients who had APM were studied. Selected demographic and clinical features were obtained from charts and operative notes. Preoperative and current functional status were determined by patient interviews. The principal outcomes were functional status at the time of followup, measured by the Physical Activity Scale of the SF-36 Health Status Inventory, and the Lysholm Knee Rating Scale. RESULTS: SF-36 scores improved from a mean of 53.7 to a mean of 18.2. The percentage of patients with satisfactory (> or = 77) Lysholm scores increased from 5% preoperatively to 73%. In multivariable analyses, Worker's Compensation (p = 0.003), worse baseline physical functional status (p = 0.007), and Grade III-IV cartilage damage (p = 0.05) were associated with worse post-operative function. CONCLUSION: The outcome of APM is generally favorable. The extent of cartilage damage was confirmed as a correlate of poor outcome. However, Worker's Compensation and preoperative physical functional status had the greatest prognostic value and should be ascertained routinely in orthopedic outcome studies.

Anatomy and relationships of the suprascapular nerve: anatomical constraints to mobilization of the supraspinatus and infraspinatus muscles in the management of massive rotator-cuff tears.

Thirty-one shoulders in eighteen cadavera were dissected to allow study of the neurovascular anatomy of the rotator cuff and to help determine the limits of mobilization of the cuff for the repair of chronic massive retracted tears. The dissection demonstrated the diameter, length, and relationships of the suprascapular nerve and its branches and made clear the dangers of extensive mobilization and advancement of the supraspinatus and infraspinatus muscles. The suprascapular nerve ran an oblique course across the supraspinatus fossa, was relatively fixed on the floor of the fossa, and was tethered underneath the transverse scapular ligament. In twenty-six (84 per cent) of the thirty-one shoulders, there were no more than two motor branches to the supraspinatus muscle, and the first was always the larger of the two. In twenty-six (84 per cent) of the thirty-one shoulders, the first motor branch originated underneath the transverse scapular ligament or just distal to it. In one shoulder (3 per cent), the first motor branch passed over the ligament. The average distance from the origin of the long tendon of the biceps to the motor branches of the supraspinatus was three centimeters. In fifteen (48 per cent) of the thirty-one shoulders, the infraspinatus muscle had three or four motor branches of the same size. The average distance from the posterior rim of the glenoid to the motor branches of the infraspinatus muscle was two centimeters. The motor branches to the supraspinatus muscle were fewer, usually smaller, and significantly shorter than those to the infraspinatus muscle. The standard anterosuperior approach allowed only one centimeter of lateral advancement of either tendon and limited the ability of the surgeon to dissect safely beyond the neurovascular pedicle. The advancement technique of Debeyre et al., or a modification of that technique, permitted lateral advancement of each muscle of as much as three centimeters and was limited by tension in the motor branches of the suprascapular nerve. In some situations, the safe limit of advancement may be even less. We concluded that lateral advancement of the rotator cuff is limited anatomically and may place the neurovascular structures at risk.

Range of motion in contemporary total hip arthroplasty. The impact of modular head-neck components.

The prosthetic range of motion (PROM) of two modular total hip arthroplasty (THA) systems and one older nonmodular comparison system was evaluated. The head-neck geometry of the modular systems resulted in a smaller PROM than the nonmodular system. Longer head-neck components commonly had flanges, which caused the greatest reduction in PROM. This effect became more pronounced as head size decreased. Modular head-neck components offer recognized benefits but can be associated with notably smaller ROM and increased risk of prosthetic impingement. The surgeon should be aware that in modern systems PROM decreases when neck width is increased. Moreover, in cases of prosthetic instability the potential role of the flange of a modular head should be evaluated. Methods are suggested for maximizing PROM clinically through preoperative planning, optimal femoral neck resection, and implant utilization.

The antishock pelvic clamp.

Unstable posterior pelvic ring disruptions are frequently accompanied by severe venous bleeding and hypotension. Mechanical stabilization has been shown to help reduce such blood loss. A new external fixator called an antishock clamp provides direct reduction and compression of such fracture-diastases about the sacroiliac joint. It is used acutely to rapidly stabilize the posterior pelvic ring in hypotensive patients. The simplicity of design allows the device to be applied in less than ten minutes in the emergency room. Most importantly, it does not interfere with the ability to carry out subsequent laparotomy or other required procedures. Although more clinical experience is needed, the clamp has provided hemodynamic stabilization accompanying fracture reduction. The device is not expected to be of benefit in the cases with significant bleeding of arterial origin.

Isolated rupture of the tendon of the subscapularis muscle. Clinical features in 16 cases.

Traumatic rupture of the tendon of the subscapularis muscle was documented as an isolated lesion in the shoulders of 16 men. The injury was caused either by forceful hyperextension or external rotation of the adducted arm. The patients complained of anterior shoulder pain and weakness of the arm when it was used above and below the shoulder level. They did not experience shoulder instability. The injured shoulders exhibited increased external rotation and decreased strength of internal rotation. A simple clinical manoeuvre called the 'lift-off test', reliably diagnosed or excluded clinically relevant rupture of the subscapularis tendon. Confirmation of the clinical diagnosis was best achieved by ultrasonography or MRI, but arthrography or CT arthrography were also useful. Surgical exploration confirmed the diagnosis in every case. Repair of the ruptured tendon was technically demanding and required good exposure to identify and protect the axillary nerve.

Incidence of heterotopic ossification after total hip replacement: effect of the type of fixation of the femoral component.

The incidence and severity of heterotopic ossification after sixty-five consecutive primary uncemented total hip replacements were compared with those after seventy consecutive primary hybrid total hip replacements (consisting of an uncemented acetabular component and a cemented femoral component). All patients had had the arthroplasty because of osteoarthrosis. The sex distribution, prevalence of bilateral disease of the hip, and frequency of previous operations were similar in both groups. All of the operations were performed by one surgeon who used the same operative approach. Preoperative, immediate postoperative, and six-month follow-up radiographs were reviewed for all patients. For 90 per cent of the hips, radiographs that were made after a minimum follow-up of one year were also reviewed. In the group of patients who had an uncemented femoral component, there was a statistically significant increase in the frequency of heterotopic bone and in its severity. Either none or only class-I ectopic bone developed in 74 per cent of the hips in the hybrid group, compared with 40 per cent of the hips in the uncemented group (p less than 0.005). In contrast, class-III or IV heterotopic ossification was evident in 13 per cent of the hips in the uncemented group (p less than 0.005). None of the patients in the hybrid group needed reoperation for excision of ectopic bone, but four (6 per cent) of the patients in the uncemented group needed such a reoperation because of severe limitation of motion.(ABSTRACT TRUNCATED AT 250 WORDS)

Elevated-rim acetabular components. Effect on range of motion and stability in total hip arthroplasty.

The effect of "elevated-rim" (ER) acetabular components on prosthetic range of motion (ROM) and stability was studied in a laboratory simulator using three contemporary total hip arthroplasty (THA) systems. Acetabular components were tested in positions simulating both normal alignment and excess abduction. The geometry of the implants differed between systems--two types were identified, and their effect on ROM in comparison with their corresponding plain liners were quantified. The ability of the liners to improve instability appeared to be dependent on the cause of instability, the orientation of the metal shell and ER liner, and the ER liner geometry. The routine use of ER liners in otherwise satisfactorily positioned acetabular components appeared to offer no demonstrable benefit and raised concern over theoretical disadvantages. The primary indication for these implants appeared to be in cases of instability due to acetabular malposition in which the metal shell is already well fixed by cement or bone ingrowth or cannot be readily changed.

Results of cementless revisions of total hip arthroplasties using the Harris-Galante prosthesis.

Sixty patients were treated with Harris-Galante prosthesis for failed, nonseptic, cemented total hip arthroplasties. The minimum follow-up period was 12 months, although 23 patients were followed for two or more years. Acetabular bone grafting was done in 86% and femoral bone grafting in 57% of the patients. The average postoperative hip score was 84 (range, 48-100). Seventy-one percent of the patients were rated good or excellent. Among those with a minimum two-year follow-up examination, 73% had good or excellent results. Ninety-six percent had no, slight, or only mild pain. None of the components has required revision. No pads have become loose or displaced and no sepsis has occurred. One femoral component has subsided, but the patient is asymptomatic. No socket has migrated. The results are excellent for this group of patients.