Developments in carbon prosthetics

Pyrocarbon interposition shoulder arthroplasty in young arthritic patients: a prospective observational study

BACKGROUND

We evaluated survival and midterm results of pyrocarbon interposition shoulder arthroplasty (PISA) in arthritic patients younger than 65 years.

METHODS

Fifty-eight PISAs (InSpyre; Tornier-Wright, Bloomington, MN, USA), implanted in 56 patients between 2010 and 2015, were prospectively observed. The mean age at surgery was 52 ± 13 years. The cause was primary osteoarthritis (18), fracture sequelae (16), post-instability arthritis (15), aseptic necrosis (3), inflammatory disease (2), and failed hemiarthroplasty (4); 34 shoulders (61%) had previously undergone surgery. Glenoid erosion was assessed in 4 grades according to the Sperling classification. Humeral erosion was also assessed in 4 grades. Multivariate analysis was used to determine predisposing risk factors for both humeral and glenoid erosion.

RESULTS

At a mean follow-up of 47 ± 15 months, survival rate was 90%. Six patients (10%) required conversion to reverse total shoulder prosthesis for painful glenoid erosion (n = 2) and humeral erosion with greater tuberosity stress fractures (n = 4). The mean Constant score and subjective shoulder value significantly increased from 36 ± 14 points to 70 ± 15 points and 32% ± 14% to 75% ± 19%, respectively (P < .001). Humeral medialization was observed in 78% of the cases with increased pain score. Uncorrected anteroposterior implant subluxation (12 cases) was associated with lower Constant score (50 points vs. 72 points; P = .02) and lower subjective shoulder value (53% vs. 78%; P = .002). On multivariate analysis, no risk factors for glenoid or humeral erosion were found.

CONCLUSION

At midterm follow-up, PISA does not protect from progressive glenoid erosion and can lead to greater tuberosity erosion and stress fractures. Longer follow-up is required to see whether PISA survival will be superior to that of hemiarthroplasty.

Advances in Proximal Interphalangeal Joint Arthroplasty: Biomechanics and Biomaterials

Proximal interphalangeal (PIP) joint arthritis is a debilitating condition. The complexity of the joint makes management particularly challenging. Treatment of PIP arthritis requires an understanding of the biomechanics of the joint. PIP joint arthroplasty is one treatment option that has evolved over time. Advances in biomaterials have improved and expanded arthroplasty design. This article reviews biomechanics and arthroplasty design of the PIP joint.

Pyrolytic carbon hemiarthroplasty in the management of proximal interphalangeal joint arthritis

PURPOSE

To review clinical, subjective, and radiographic results of pyrocarbon hemiarthroplasty for proximal interphalangeal (PIP) joint arthritis.

METHODS

A total of 42 fingers in 38 patients underwent PIP joint hemiarthroplasty between 2005 and 2011. Preoperative diagnoses included 28 with osteoarthritis or posttraumatic arthritis and 10 with inflammatory arthritis. Average age at the time of surgery was 56 years. Digits treated included: index (10), middle (20), ring (9), and little (3). Average follow-up was 4.6 years (minimum, 2 y).

RESULTS

There was considerable improvement in patient satisfaction measures including Canadian Occupational Performance Measure for both performance and satisfaction and Disabilities of the Arm, Shoulder, and Hand and visual analog scale pain scores. There was no significant change in motion or grip and pinch strength after surgery. Four joints were revised for failure: 3 underwent arthrodesis and 1 was converted to a silicone PIP joint arthroplasty. Radiographic outcomes in surviving implants demonstrated a Sweets and Stern grade 0 in 37 implants and grade 3 in 1.

CONCLUSIONS

Pyrocarbon hemiarthroplasty appears to be a viable alternative to total joint arthroplasty in the treatment of PIP joint arthritis. Clinical and patient satisfaction outcomes compared favorably with published outcomes of arthroplasty. Radiographic outcomes of PIP joint hemiarthroplasty were encouraging with respect to implant position and loosening. Compared with total joint arthroplasty, proximal hemiarthroplasty is a simple procedure that preserves more bone stock and would allow for better success of salvage options such as arthrodesis and revision arthroplasty.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

OUTCOME OF PYROCARBON PROXIMAL INTERPHALENGEAL JOINT REPLACEMENT

Pyrocarbon arthroplasty of the proximal interphalangeal joint (PIPJ) has been reported to provide excellent pain relief when treating osteoarthritis of the hand. We retrospectively reviewed 20 PIPJ arthroplasties performed on 14 patients by a single surgeon using Ascension prosthesis. The mean follow up period was 3.5 years (range 1–7 years). Excellent pain relief was noted at the final follows-up. The mean range of motion improved from 40° pre-operatively to 70° post-operatively which was statistically significant. Twelve patients had significant improvement in quality of life and would consider similar procedure for other fingers. Radiological assessment revealed an average of 1 mm subsidence and there was no correlation noted between subsidence, migration and ROM at the final follow-up. Stiffness was the main complication and was comparable with other studies. The results of this series are encouraging and demonstrate excellent to good outcome in 86% of patients at the mid-term follow-up.

Preliminary results of nonconstrained pyrolytic carbon arthroplasty for metacarpophalangeal joint arthritis

PURPOSE

To review early outcomes of arthritic metacarpophalangeal (MCP) joints treated with nonconstrained pyrolytic carbon implants to evaluate efficacy, clinical outcomes, and durability.

METHODS

One hundred forty-two consecutive arthroplasties (61 patients) were retrospectively reviewed. Diagnoses included osteoarthritis (OA), traumatic arthritis, and inflammatory arthritis. One hundred thirty were primary joint replacements, and 12 were prior-silicone revisions. The average patient age was 55 years (range, 21-77 years); 36 patients were women and 25 were men. Average follow-up period was 17 months (range, 3-42 months), and 43 patients were followed up for a minimum of 1 year.

RESULTS

For OA patients, according to the analog pain scale used, pain decreased from 73.0 to 8.5 of 100, functionality increased from 20.1 to 86.6 of 100, and appearance improved from 62.7 to 93.6 of 100. The rheumatoid arthritis (RA) group showed decreased pain from 43.1 to 8.9 of 100, functional improvement from 26.7 to 83.3 of 100, and increased appearance from 25.2 to 77.1 of 100. At 1 year, satisfaction was greater than 90% for both groups. Arc of motion for OA patients improved from 44 degrees to 58 degrees . Oppositional pinch increased 126%, and grip strength improved 40%. Rheumatoid arthritis patients increased their MCP joint motion arc from 32 degrees to 45 degrees . Oppositional pinch increased 89%, but grip strength decreased. Radiographs at 1 year demonstrated stable prostheses in all of the OA joints. The RA group overall demonstrated evidence of axial subsidence (10.5% of joints) and periprosthetic erosions (16.4% of joints). In RA joints with greater than 1-year follow-up period, 55.0% had axial subsidence, 95.0% had an increased radiolucent seam, and 45.0% had periprosthetic erosions. The overall implant survivorship is 141 joints to date. The overall minor complication rate was 6%, and major complication rate was 9%.

CONCLUSIONS

Preliminary results suggest that pyrolytic carbon MCP joint arthroplasty provides good pain relief, patient satisfaction, and functional improvement in managing OA and select cases of RA. Longer follow-up evaluation will help validate these promising early results.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Pyrolytic carbon proximal interphalangeal joint arthroplasty: results with minimum two-year follow-up evaluation

PURPOSE

To retrospectively review the surgical technique, postoperative therapy/splinting protocols, and clinical and radiographic outcomes of patients who had pyrolytic carbon proximal interphalangeal (PIP) joint arthroplasty.

METHODS

A total of 50 PIP joint replacements in 35 patients were performed with a minimum follow-up period of 27 months. Indications for surgery included pain, decreased range of motion, instability, and/or deformity. The preoperative diagnosis was osteoarthritis in 14, rheumatoid arthritis in 11, and posttraumatic arthritis in 10. There were 20 women and 15 men affected. The average age at the time of surgery was 53 years. The fingers replaced included the index (15), middle (18), ring (10), and small (7). The preoperative arc of motion averaged 40 degrees (0 degrees-60 degrees ), and the pinch and grip measurements averaged 3 and 19 kg, respectively. The preoperative pain scores averaged 6 (scale, of 0-10) on a visual analog space scale.

RESULTS

The arc of motion was 47 degrees after surgery, and the average pinch and grip measurements were 4 and 25 kg, respectively. Pain scores improved to 1. At the final follow-up evaluation the overall patient satisfaction was nearly 80%. The results of index finger PIP replacements are compatible with other digits. Fourteen joints (in 14 patients) to date have required additional procedures to improve or maintain joint motion/function or pain; 5 for minor reasons and 9 for major complications. The revision arthroplasty rate was 8%. No infections were noted. Although not medically necessary, 2 patients requested and had an amputation. Radiographic subsidence and subsequent settling (in accordance with Wolff's law) without apparent loosening occurred in 20 joints.

CONCLUSIONS

Our 2-year minimum follow-up evaluation of pyrolytic carbon implant arthroplasty showed improved pain relief and good overall patient satisfaction. Twenty-eight percent of patients required a second procedure and 8% required a revision arthroplasty. Radiographs showed gross changes in implant and eventual settling to a stable position in 40% of the joints. A longer follow-up period will help to better determine the efficacy of this implant.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic, Level IV.

A trial of Biolite ventilation tubes in children: is further use warranted?

A prospective controlled pilot study was undertaken in which Biolite (carbon-coated) ventilation tubes were placed in 44 ears and a conventional silicone tube in the contralateral ear. Long-term follow-up of these patients has revealed little difference in the incidence of tube occlusion or early extrusion. In addition, there were several disadvantages noted with the Biolite tubes: incomplete coating of the tube (especially within the lumen), shedding of the Biolite coating over time, "tattooing" of the tympanic membrane, poor otoscopic visibility, and the higher cost of these tubes. Since the Biolite tube has no documented advantages and, actually, several disadvantages, we believe its use in the treatment of middle ear disorders should be discontinued until significant benefits are demonstrated and present deficiencies are corrected.