Pyrocarbon hemiarthroplasty and the shoulder: biomechanical and clinical results of an emerging treatment option

While shoulder hemiarthroplasty is still used to treat young patients with shoulder pathology, the use of this procedure has substantially declined in recent years due to its significant complication profile. Glenoid wear with arthrosis is one of the major postoperative complications following shoulder hemiarthroplasty, and efforts to prevent this complication led many scientists to explore alternative weight-bearing surfaces on arthroplasty implants to decrease joint wear and improve patient outcomes. Pyrolytic carbon, or pyrocarbon, is a material that has better biocompatibility, survivorship, strength, and wear resistance compared to the materials used in traditional shoulder hemiarthroplasty. Pyrocarbon implants have been used in orthopedics for over 50 years; recently, their utility in shoulder hemiarthroplasty has garnered much interest. The purpose behind the use of pyrocarbon in shoulder hemiarthroplasty is to decrease the risk of progressive glenoid wear, especially in young active patients in whom joint preservation is important. Promising survivorship and outcomes have been demonstrated by recent studies, including limited glenoid wear following pyrocarbon hemiarthroplasty. Nevertheless, these clinical studies have been limited to relatively small case series with limited long-term follow-up. Accordingly, additional research and comparative studies need to be conducted in order to properly assess the therapeutic efficacy and value of pyrocarbon hemiarthroplasty.

Thumb Carpometacarpal Implant Arthroplasty

Thumb carpometacarpal implant arthroplasty aims to preserve thumb length and motion and to provide pain relief and functional recovery after a short postoperative time. For several decades, implant arthroplasty has been performed with total trapeziometacarpal joint prosthesis using the concept of "ball-and-socket" joint. More recently, pyrocarbon implants used as hemiarthroplasty or interposition arthroplasty have been proposed. Whatever the type of arthroplasty used, the surgical technique must be precise and may require a learning curve. Implant arthroplasty has proven that in the medium and long-term, it may be considered as a valid and reliable alternative to trapeziectomy.

Poor results after pyrocarbon interpositional shoulder arthroplasty

BACKGROUND

This study aimed to describe the clinical outcomes and complications of 10 cases of pyrocarbon interposition shoulder arthroplasty (PISA).

METHODS

The clinical and radiographic records of 10 patients who underwent PISA using the InSpyre shoulder prosthesis (Tornier-Wright) between July 2012 and March 2017 were reviewed. The mean age at surgery was 55 years. Surgical indications included patients aged <60 years with Walch type B glenoid glenohumeral osteoarthritis (n = 7), avascular necrosis (AVN) of the humeral head (n = 1), or secondary severe glenohumeral osteoarthritis with axillary nerve dysfunction (n = 2). Outcomes of interest were postoperative complications and need for revision surgery, preoperative and postoperative patient-reported outcomes (Constant score [CS] and Subjective Shoulder Value [SSV]), and range of motion. The radiographic characteristics of the implants were evaluated.

RESULTS

Among the 10 patients, 5 underwent revision to reverse shoulder arthroplasty during the study period owing to poor clinical outcomes based on the CS and SSV. All 5 revised patients had Walch type B glenoid morphology at the time of the index procedure. The mean time to revision surgery in this subset of patients was 60 months. The remaining 5 patients who did not undergo any revision procedure had significant improvement in mean CS and SSV from 30-65 points and 32%-87%, respectively, but at a shorter duration of follow-up of 35 months.

CONCLUSION

High clinical failure rate and poor results at mean 5-year follow-up were found in younger PISA patients with baseline Walch B glenohumeral osteoarthritis. We would caution against use of PISA in this challenging patient population. PISA yielded more favorable short-term outcomes in patients with humeral-sided deformity or severe secondary glenohumeral osteoarthritis with axillary nerve dysfunction; however, longevity of the implant in this population remains unclear.

Partial arthroscopic trapeziectomy and stabilisation by ligamentoplasty: Outcomes in patients younger than 60years

BACKGROUND

Thumb carpometacarpal joint (TCMJ) osteoarthritis is the fourth leading cause of referral to elective hand surgery. None of the available techniques has proved superior over the others. Some techniques carry unacceptable risks for younger patients, such as loss of strength and shortening of the thumb column after total trapeziectomy, or wear and loosening after total arthroplasty. Our objective was to assess outcomes after partial arthroscopic trapeziectomy (PAT) combined with suspensionplasty using the abductor pollicis longus (APL) tendon in patients younger than 60years of age.

HYPOTHESIS

PAT combined with suspensionplasty using the APL tendon in patients younger than 60years would restore strength in the medium-term without further surgery.

MATERIAL AND METHODS

We retrospectively included consecutive patients operated between 2007 and 2017, in a single centre, and aged less than 60years. All patients had isolated TCMJ osteoarthritis stage 1 to 3 according to Eaton and Glickel classification that remained symptomatic despite optimal conservative treatment. We collected pain intensity, range of motion, strength, the Nelson Hospital Score (NHS), and the Patient-Rated Wrist Evaluation (PRWE) score. Radiographs were reviewed.

RESULTS

We included 27 patients, of whom 6 had surgery on both thumbs, yielding 33 thumbs for the analysis. Mean follow-up was 64.7months (range: 10.6-136.5months). Pain intensity, grip strength, and key-pinch strength were significantly improved (p<0.001), with no difference between men and women. No differences were found for the Kapandji score (p=0.2) or TCMJ hyperextension (p=0.06). At last follow-up, the mean NHS was 83.2±19.4 and the mean PRWE was 15.4±17.9. Mean sick leave duration was 5.4weeks (range: 1-24weeks). Only 2 patients, both in manual jobs, were unable to return to work. The radiographs at last follow-up showed the development of moderate TCMJ narrowing in 14 patients and evidence of scapho-trapezio-trapezoid (STT) osteoarthritis in 10 patients. No patient experienced complex regional pain syndrome or injury to the sensory branch of the radial nerve. A single patient required further surgery for persistent pain.

DISCUSSION

Patients younger than 60years who are treated with this minimally invasive technique are likely to experience sustained improvements in both strength and pain intensity. Total trapeziectomy and pyrocarbon implant has also been evaluated in younger patients, who experienced pain relief and strength gains but had lower levels of satisfaction and developed complications inherent in the implants. The short time off work and low morbidity make our technique a procedure of choice in younger patients. To build on this study, a comparison of PAT and arthroplasty would be of interest.

LEVEL OF EVIDENCE

IV.

Pyrocarbon implants for the basal thumb arthritis

Silicone implants for the treatment of basal thumb arthritis were first proposed in the 1970's by Swanson. They became extremely popular and despite good functional results, the high rate of complications such as instability, material breakage and foreign body reactions led to them being progressively abandoned by most surgeons. Pyrocarbon implants were introduced at the beginning of the 2000's. A large range of different implant models that can be used for either hemiarthroplasty or interposition arthroplasty. For some implants, a supplemental ligamentoplasty procedure is required to avoid instability. Miniaturization of some implants provides new options for minimally invasive surgery, which is relevant in low and medium grades of osteoarthritis, especially for young, active patients. Medium- and long-term follow-up have now been reached by some pyrocarbon interpositions. Their results confirm that these implants are a reliable alternative to other techniques. This paper focuses on the surgical techniques and outcomes of pyrocarbon implants for the treatment of basal thumb arthritis. It is based on published data and the author's experience.